JP7804178B2 - Autonomous delivery robot - Google Patents

Description

The present invention relates to an autonomous mobile robot (AMR), and in particular to an autonomous delivery robot device that can deliver packages stored in a cargo compartment inside the robot to a destination.

The number of parcels has surged in recent years, driven by the spread and expansion of electronic commerce (EC) and the special demand for EC due to the COVID-19 pandemic, and the parcel delivery market is booming. According to the Ministry of Land, Infrastructure, Transport and Tourism, since the state of emergency was declared in April 2020, the number of parcels delivered has remained approximately 10% higher than the previous year. Meanwhile, the increase in parcels has increased the workload of delivery drivers, and labor shortages have become an issue in the logistics industry. Furthermore, the COVID-19 pandemic has led to an increase in demand for non-face-to-face and non-contact delivery, and it is expected that demand for non-contact delivery will increase even further during and after the COVID-19 pandemic.

As one way to address the increase in parcels delivered, the increased workload on delivery drivers, and labor shortages, domestic trials are underway to reduce the workload of delivery drivers by having some of their work delegated to autonomous mobile robots (AMRs) for automated delivery, and practical application is also underway overseas (see Non-Patent Document 1 below).

In addition, as a response to the increasing workload of delivery drivers, labor shortages, and the demand for contactless delivery, a demonstration experiment is underway in which the task of drop-off delivery (a delivery method in which the delivery person leaves the package at a designated location rather than handing it directly to the recipient) is entrusted to an autonomous robot, which then automatically leaves the package at the destination (see Non-Patent Document 2 below). Drop-off delivery allows the delivery person to leave the package at a designated location without handing it over, regardless of whether the recipient is at home or not. This effectively reduces the effort and time required for redelivery, thereby significantly contributing to improved work efficiency (delivery efficiency). It has also been reported that delivery efficiency has improved as the redelivery rate has dropped significantly amid the self-restraint on going out due to the COVID-19 pandemic.

"Delivery Robot DeliRo," [online], [Retrieved May 20, 2021], Internet, <URL: https://www.zmp.co.jp/products/lrb/deliro> "Amoeba Energy and Japan Post Succeed in Continuous Delivery Using Robots," [online], [Retrieved May 20, 2021], Internet, <URL: https://www.lnews.jp/2020/01/m0130401.html>

When using the delivery robot described in Non-Patent Document 1, the recipient of a package can collect it by removing it from the delivery robot's box. However, if the recipient is not at the delivery destination, the robot must either wait at the delivery destination for a certain period of time or return to the base and then redeliver the package.

Furthermore, the delivery robot described in Non-Patent Document 2 can automatically place and deliver packages by itself, which avoids situations where the robot has to wait at the delivery destination for a certain period of time even if the recipient is not at home, or has to return to the base and then redeliver the package. However, it does have the following drawbacks. First, with the delivery robot described in Non-Patent Document 2, the loading space for packages is set near the floor to make it suitable for placing packages on the floor, so even during normal deliveries, the recipient is forced to crouch down to receive the package. This is also true when loading and unloading packages to be delivered at delivery bases, etc., and is a factor that reduces the efficiency of the worker's loading work. Furthermore, because the delivery robot described in Non-Patent Document 2 uses a pair of dedicated crawlers on the left and right as a means of travel, it is impossible or extremely difficult to adapt or replace it with a delivery robot equipped with more practical wheels, etc., and in this respect, it can be said that the degree of flexibility is low.

It is believed that demand for delivery robots that can make up for labor shortages and also support contactless delivery is not limited to the home delivery industry, but also in retail, hospitals, hotels, and other industries. Therefore, the question of how to realize last-mile logistics services (logistics services from the final base to the end user) is becoming an important issue for industries that require package delivery.

In consideration of this current situation, the applicant has developed an autonomous delivery robot R' as shown in Figure 19 and is currently conducting tests toward practical application (Patent Application No. 2021-101787). The autonomous delivery robot R' comprises an autonomously movable driving means T' and a delivery device 2' mounted on a robot main body 1' having a cargo compartment. The robot is configured to be able to select between a delivery process in which the delivery device 2' uses a lift-down mechanism 4' to lift down the bottom plate 31' of the movable basket 3' to a delivery position where it contacts the floor of the delivery destination, and a normal delivery process without operating the lift-down mechanism 4'.

This type of delivery robot R' is configured to discharge the package N' by tilting the bottom plate portion 31' of the movable basket portion 3' via a mechanical link member that is linked to the movement of the lift-down mechanism 4' accompanying the lift-down operation of the package N'.

However, with this configuration, when the robot arrives at a delivery point based on a self-location estimation algorithm (e.g., adaptive Monte Carlo localization (AMCL)), simply performing the delivery process immediately at the arrival point may result in the package being left in the wrong position or orientation at the delivery target point.

Furthermore, in a delivery device equipped with a lift-down mechanism, when the bottom plate of the movable basket is tilted to discharge the package onto the package delivery surface (floor, table, etc.), and the autonomous mobile robot then travels backward to completely place the package on the floor, the bottom surface (rolling surface) of the package is not necessarily smooth, and if the center of gravity of the package is eccentric, the position and posture of the package may shift when it is rolled out.

In addition, since packages come in a variety of sizes, if the robot were to guide the packages in advance according to size to prevent changes in posture within the robot's cargo compartment, it would be necessary to install a movable guide mechanism and posture sensing means within the compartment, which would complicate the structure and require additional work at the delivery point when loading the packages into the compartment.

Furthermore, if the load is light, it is likely that the load will not be completely ejected from the movable basket after the lift-down process is complete, and the load will be dragged backward to a certain extent when the robot moves backward, which can cause the load to deviate from its target posture and position.

Placing packages at the target location, facing perpendicular to the wall at the delivery destination, is an important service quality that influences customer impressions, and the same quality of delivery service is required as when a delivery person delivers. For example, there have been recent cases where delivery people were caught on surveillance cameras leaving packages in a messy manner, leading to complaints. Therefore, careful package placement is likely to be required even for autonomous delivery robots, which are being considered in industries such as logistics, retail, hospitals, and hotels.

The present invention was made in response to these issues, and its primary objective is to provide an autonomous delivery robot that can drop off and deliver packages, adjust the posture of the package and the gap distance between the package and the wall to an appropriate posture and distance (position), and perform delivery with the same quality as if the package were delivered by a delivery person.

In other words, the autonomous delivery robot of the present invention comprises a driving means capable of autonomous driving, a robot main body with a part of its internal space set as a luggage compartment, a delivery device mounted on the robot main body, and a control unit that executes at least the delivery process. The delivery device comprises a movable basket that can store packages, a lift-down mechanism that lifts down the movable basket from a storage position where the entire movable basket is stored in the luggage compartment to a delivery position where at least a part of the bottom plate of the movable basket is in contact with or close to the package delivery surface of the delivery destination, and two sensors that detect the distance between the robot main body and a surface (opposing surface) that faces the direction in which the robot main body carries out the package when the robot arrives at the delivery destination from different positions. The robot is characterized by the above-mentioned opposing surface distance detection unit, a robot body angle calculation unit that calculates the angle of the robot body relative to the opposing surface based on the detection value of the opposing surface distance detection unit, a pre-delivery correction process that corrects the position and attitude of the robot to a preset target position and target attitude based on the detection value of the opposing surface distance detection unit and the calculation value of the robot body angle calculation unit before the control unit operates the lift-down mechanism to perform the drop-off process, and a finishing push process that pushes the packages that have been moved from the movable basket unit to the package delivery surface toward the opposing surface after the lift-down mechanism is operated to lift down the movable basket unit from the storage position to the drop-off position. Here, the "surface that the robot body faces in the direction of package removal when it arrives at the delivery destination (opposing surface)" in this invention can be a "wall" such as an exterior wall or interior wall of a house. It should be noted that the "opposing surface" in the present invention does not have to be an entirely flat surface like a wall, as long as it is a surface that has a partially flat surface. Examples other than walls such as the exterior and interior walls of a house include outdoor structures (exteriors) such as walls, fences, walls, and gates, as well as pillars (pillars and beams of a house), poles (pole poles in a parking lot, etc.), legs of desks and tables, box-shaped items (trash cans, shelves, pallets, chests of drawers, etc.), stairs (stairs in front of a door, stairs inside a house, etc.), delivery boxes, elevators, garages, etc.

In this way, when performing a drop-off process to move a package stored in the luggage compartment to the delivery surface (floor, ground, etc.) at the delivery destination, the autonomous delivery robot of the present invention is configured to perform a pre-drop-off correction process, which corrects the robot body's distance from the opposing surface to a predetermined target position based on detection values from two or more opposing surface distance detection units before activating the lift-down mechanism to move the movable basket to the drop-off location (lift-down movement), and corrects the robot body's attitude relative to the opposing surface to a predetermined target attitude based on a calculation value from the robot body angle calculation unit. Here, because the autonomous delivery robot of the present invention is equipped with two or more opposing surface distance detection units that detect the distance between the opposing surface and the robot body from mutually different positions, the robot body's distance from the opposing surface can be corrected to the target position by moving the robot body using the traveling means so that, for example, the detection values from the opposing surface distance detection units are equal to each other and the absolute value of the distance approaches the target distance appropriate for drop-off. Furthermore, the autonomous delivery robot according to the present invention is equipped with a robot body angle calculation unit that calculates the angle of the robot body relative to the opposing surface based on the detection value of the opposing surface distance detection unit. By changing the orientation of the robot body using the travel means so that the value calculated by the robot body angle calculation unit approaches a preset value, the angle of the robot body relative to the opposing surface can be corrected to a target angle.

Therefore, even if the robot arrives at the delivery destination based on a self-location estimation algorithm (e.g., adaptive Monte Carlo localization (AMCL)), which is an estimation based on probability theory, by executing the pre-delivery correction process, it is possible to avoid leaving the package at the delivery destination in an incorrect position or orientation. This benefit can also be expected to eliminate cumulative deviations caused by ground characteristics or slopes when using odometry based on wheel contact for autonomous driving.

Furthermore, with the autonomous delivery robot of the present invention, after the lift-down mechanism is activated to lift down the movable basket from the storage position to the drop-off position, a finishing push process is performed to push the parcel that has been moved from the movable basket to the parcel delivery surface toward the opposing surface.By pushing the parcel toward the opposing surface while maintaining the angle of the robot body at the time of the pre-drop-off correction process, even if a deviation occurs in the parcel's delivery position or delivery posture due to the smoothness of the parcel's bottom surface (rolling surface) or an eccentricity in the parcel's center of gravity when the parcel is completely discharged, the parcel can be moved to the vicinity of the opposing surface with the specified delivery posture corrected.

With this type of autonomous delivery robot according to the present invention, there is no need to install a mechanism or posture sensing means inside the cargo compartment to guide the package in advance according to its size so that the loading posture does not change in the cargo compartment inside the robot body. This avoids a complex structure and also prevents the delivery source from having to perform unnecessary work when loading the package into the cargo compartment.

The specific means (pushing means) for pushing packages toward the opposing surface during the finishing push process in this invention is not particularly limited, and the present invention also includes aspects such as having part of the movable basket section or part of the lift-down mechanism function as the pushing means, or having the pushing means comprise a dedicated item mounted in an appropriate location on the autonomous delivery robot. Any part or dedicated item that functions as the pushing means can be considered a package priority contact part that has priority contact with the package during the finishing push process.

In particular, if the autonomous delivery robot of the present invention is equipped with a luggage priority contact section that makes priority contact with the luggage during the finishing push process, and a force measurement section that measures the force (applied force) acting on the luggage priority contact section that has made contact with the luggage, and is configured to stop the finishing push process when the measurement value of the force measurement section exceeds a predetermined threshold during the finishing push process, it becomes possible to detect that the luggage has reached the opposing surface based on changes in the measurement value of the force measurement section, and by ending the finishing push process when the luggage has been moved to a position where it will have reached the opposing surface, the luggage can be moved to an appropriate position close to the opposing surface.

The finishing push process in this invention may be a process in which, immediately after the movable basket section is lifted down from the storage position to the delivery position, the robot body at that time is moved by the traveling means in a direction toward the facing surface, thereby pushing the package toward the facing surface. However, if priority is given to completely moving the package from the movable basket section to the delivery floor, a retraction process is preferably performed in which the traveling means moves the robot body away from the facing surface immediately after the movable basket section is lifted down from the storage position to the delivery position, and the finishing push process is performed following the retraction process. In the latter case, i.e., if the finishing push process is a process performed following the retraction process in which the traveling means moves the robot body away from the facing surface, it is best to start monitoring the measurement value of the force measurement unit during the finishing push process after the robot body has been moved toward the facing surface a distance equal to the retraction movement distance during the retraction process (the distance the traveling means moved the robot body away from the facing surface). The reasons for this are as follows. In other words, if the package is heavy, the measurement value of the force measuring unit changes significantly relatively quickly when the package starts to move (move forward) from the retreating state (retreat state) toward the opposing surface again. This is a change that occurs at the point when the heavy package comes into contact with the package, even before the package reaches the opposing surface. If the finishing push process is stopped based on this change, the delivery will be completed before the package can be brought closer to the opposing surface, which can be a factor in lowering the quality of delivery compared to drop-off services performed by delivery personnel.

Therefore, in this invention, if the device is configured to start monitoring the force measurement unit's measurement value after the device has moved (moved forward) toward the opposing surface a distance equal to the retraction movement distance during the retraction process, monitoring of the force measurement unit's measurement value will not have started at the time of contact with the heavy package, which is before the package reaches the opposing surface. Therefore, changes in the measurement value at that time are ignored, and it is possible to reliably detect that the package has reached the opposing surface based on the first change in the measurement value after monitoring of the force measurement unit's measurement value begins. If the finishing push process is stopped based on this change, delivery can be completed with the package close to the opposing surface.

In the present invention, if the luggage is lightweight and the evacuation process is performed when the luggage has not been completely discharged from the movable basket onto the luggage delivery surface at the time the lift-down process is completed, the luggage may be dragged backward to a certain extent (in the direction of evacuation of the robot body) by the evacuation movement, causing a deviation from the originally intended position and posture of the luggage. However, with the autonomous delivery robot of the present invention, by performing the above-mentioned finishing push process, the luggage can be moved to the appropriate delivery target position near the opposing surface after the deviation has been corrected and the luggage has been brought to the appropriate delivery target posture.

According to the present invention, the position and posture (orientation) of the robot body relative to the opposing surface (a wall as a typical example) are corrected to the appropriate target position and posture before performing the drop-off/delivery process, the drop-off/delivery process is performed in that corrected state, and a finishing push process is then performed.This allows the package placed on the delivery surface for drop-off delivery to be delivered in the appropriate posture, in contact with or close to the opposing surface, and the delivery is completed.This makes it possible to provide an autonomous delivery robot that can perform drop-off/delivery processes with the same quality as if it were delivered by a delivery person.The autonomous delivery robot of the present invention is not limited to the home delivery field, but can also be used in fields such as retail, hospitals, and hotels.Therefore, the autonomous delivery robot of the present invention is highly versatile and can be used in many industries and fields as an autonomous delivery robot with the function of delivering, transporting, or transporting items.

1 is a schematic diagram of an overall view of an autonomous delivery robot according to one embodiment of the present invention. FIG. 10 is an overall perspective view of the autonomous delivery robot at the time of completion of delivery in the same embodiment. FIG. 10 is a diagram showing an autonomous delivery robot executing a normal delivery process in the same embodiment. FIG. 2 is a side view showing the mechanism of the delivery device in the embodiment immediately after the initial operation, with some parts omitted. FIG. 10 is a rear view showing the mechanism of the delivery device in the embodiment immediately after the initial operation, with some parts omitted. 5 is a diagram illustrating the time point at which the lift-down process is completed in the embodiment, corresponding to FIG. 4; FIG. 6 is a diagram illustrating the time point at which the lift-down process is completed in the embodiment, corresponding to FIG. 5; FIG. 5 is a diagram illustrating a state during a lift-down process in the same embodiment, corresponding to FIG. 4; FIG. 5 is a diagram corresponding to FIG. 4 and illustrating a state at the time when the auxiliary wheels start to contact the ground during the lift-down process in the same embodiment; FIG. 5 is a view corresponding to FIG. 4 showing a state in which the bottom plate portion is tilted by the ground reaction force of the auxiliary wheels during the lift-down process in the same embodiment; FIG. 5A and 5B are diagrams illustrating processing contents of pre-placement correction processing in the embodiment. 10 is a flowchart showing delivery processing (drop-off) in the embodiment. FIG. 10 is a schematic side view of the autonomous delivery robot immediately after initial operation in the same embodiment. 14 is a diagram corresponding to FIG. 13 and showing the time point at which the door opening process is completed in the embodiment; 14 is a diagram corresponding to FIG. 13 and showing the time point at which the outrigger grounding process is completed in the embodiment; FIG. 14 is a diagram showing the time point at which the lift-down process is completed in the embodiment, corresponding to FIG. 13; FIG. FIG. 10 is a diagram showing a change in the measurement value of the force measuring unit during the finish pressing process in the same embodiment. 5A and 5B are diagrams illustrating target position setting conditions in the pre-placement correction process according to the embodiment; An overall view of an autonomous delivery robot for which the applicant has previously applied for a patent.

One embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, the autonomous delivery robot R of this embodiment comprises an autonomously traveling vehicle T, a robot main body 1 with a portion of its interior space designated as a cargo compartment 1S, a delivery device 2 mounted on the robot main body 1, and a control unit C that controls the operation of the autonomous delivery robot R to perform delivery or standard delivery depending on the selected delivery type (delivery method). Note that FIG. 1 shows an overall external view of the autonomous delivery robot R in a state (normal state) in which it is not performing a delivery process upon arrival at the delivery destination, and FIG. 2 shows an overall external view of the autonomous delivery robot R performing a delivery process. Note that while no packages are shown in either drawing, the autonomous delivery robot R of this embodiment is suitable for delivering packages with a box-like external shape (a box containing the package), such as package N' shown in FIG. 19. Of course, packages with external shapes other than a box can also be delivered by the autonomous delivery robot R of this embodiment.

In this embodiment, the travelling means T is equipped with two front wheels T1 and two rear wheels T2, and is capable of moving forward and backward in the fore-and-aft direction X where the front wheels T1 and rear wheels T2 are aligned, and can move sideways in the Y direction by steering while stopped (a process in which the front wheels T1 and rear wheels T2 are each turned 90 degrees to change the direction of forward and backward movement). It is also possible to turn left or right by changing the direction (swinging) the front wheels T1 and rear wheels T2. The part of the autonomous delivery robot R that is equipped with such travelling means T and supports the robot body 1 can be considered a cart B.

The robot body 1 is an autonomous mobile robot (AMR) capable of autonomously moving to a destination by means of a travelling means T and capable of recognizing its surroundings. In this embodiment, the robot body 1 is box-shaped and equipped with a door D that can open and close the interior space. Part of the interior space of the robot body 1 is configured as a luggage compartment 1S capable of accommodating luggage (see FIG. 2). In this embodiment, the robot body 1 is a substantially rectangular parallelepiped with a predetermined height and an elongated planar shape in the fore-and-aft direction X along which the front wheels T1 and rear wheels T2 are aligned. An opening K formed on only one side of the robot body 1 can be opened and closed by the door D (right door D1, left door D2). Specifically, the pair of doors D (right door D1, left door D2) are configured to open and close in a double door style (see FIG. 2). In this embodiment, the pair of doors D are arranged side by side in the fore-and-aft direction X. In the following description, the door D on the front wheel T1 side is referred to as the left door D2, and the door D on the rear wheel T2 side is referred to as the right door D1.

The autonomous delivery robot R according to this embodiment is configured to be able to store packages in a movable basket 3 set in the luggage compartment 1S. As shown in FIG. 3, when at least one of the left and right doors D (right door D1, left door D2) is in the open position (DB), a user (such as a package recipient P or a package sorter) can access the luggage compartment 1S through the opening K. This allows the package recipient P to remove packages set in the luggage compartment 1S, and allows the package sorter to load (store) packages into the luggage compartment 1S or remove (collect) packages from the luggage compartment 1S.

In this embodiment, as shown in FIG. 3, the movable basket 3 set in the luggage compartment 1S is mounted at a height that allows an adult P of average height to access the movable basket 3 without having to crouch. In other words, in the case of normal delivery, the movable basket 3 set in the luggage compartment 1S is mounted at an appropriate height that makes it easy for the parcel recipient P to remove parcels. This also means that the movable basket 3 is mounted at an appropriate height that makes it easy for a parcel sorter at the delivery source (delivery origin) to store and collect parcels from the movable basket 3 set in the luggage compartment 1S.

As shown in Figures 2, 4, and 5, the movable basket section 3 comprises a bottom plate section 31 on which luggage can be placed, and a pair of upright plate sections 32 arranged in an upright position from the edge of the bottom plate section 31 on the front wheel T1 side and the edge on the rear wheel T2 side. Rotatable rollers 34 are arranged in multiple rows in a predetermined area of the bottom plate section 31 of the movable basket section 3 that directly contacts the luggage (see Figure 2). Note that Figures 4 and 5 omit a portion of the bottom plate section 31 including the rollers 34. The upper ends of the upright plate sections 32 are connected to each other by rod-shaped connecting sections 35 (see Figures 4 and 5). The movable basket section 3 constitutes the delivery device 2 and is movable by the lift-down mechanism 4.

The delivery device 2 is equipped with a lift-down mechanism 4 that lifts down the movable basket 3 set in the luggage compartment 1S to a position where it contacts or is close to the floor F, an outrigger mechanism 5 that extends outward from the robot body 1 to prevent it from tipping over, and a door opening/closing mechanism (not shown) that opens and closes the doors D (right door D1, left door D2). In this embodiment, the control unit C is configured to be able to control the travel of the cart B and the operation of each mechanism (lift-down mechanism 4, outrigger mechanism 5, door opening/closing mechanism). The control unit C is mounted in an appropriate position on the autonomous delivery robot R and is only shown schematically in Figure 1.

The autonomous delivery robot R of this embodiment has a delivery device 2, consisting of assemblies with the above-mentioned functions (lift-down mechanism 4, outrigger mechanism 5, door opening/closing mechanism), and its control unit C mounted on top of a trolley B.

As shown in Figures 4 to 7, the lift-down mechanism 4 lifts down the movable basket 3 from a storage position (3A) where the entire movable basket 3 is stored in the luggage compartment 1S to a placement position (3B) where at least a portion of the bottom plate 31 of the movable basket 3 is in contact with or near the floor F (baggage delivery surface) of the delivery destination. Figures 4 and 5 are side and rear views, respectively, partially illustrating the internal mechanism of the placement device 2 when the movable basket 3 is set in the storage position (3A). Figures 6 and 7 are views corresponding to Figures 4 and 5, respectively, showing the movable basket 3 moved to the placement position (3B).

In this embodiment, the lift-down mechanism 4 is configured using a parallel link mechanism 41. The parallel link mechanism 41 includes a first link arm 43 having one end attached to the drive input shaft 42 (first parallel link shaft 42) and a second link arm 45 having one end attached to a second parallel link shaft 44 fixed at a position relatively close to the first parallel link shaft 42. The other end of the first link arm 43 is attached to the upright plate portion 32 of the movable car section 3 via an axis (third parallel link shaft 46), and the other end of the second link arm 45 is attached to the upright plate portion 32 of the movable car section 3 via an axis (fourth parallel link shaft 47). The parallel link mechanism 41 switches between a storage position (4A) (see FIGS. 4 and 5 ) in which the first link arm 43 and the second link arm 45 are stored in the internal space of the robot main body 1 in an upright position (upright position tilted at a predetermined angle) and aligned substantially parallel to each other, and a lift-down position (4B) (see FIGS. 6 and 7 ) in which the first link arm 43 and the second link arm 45 are tilted in a direction that throws the movable basket 3 from the luggage compartment 1S through the opening K of the robot main body 1 and out of the luggage compartment 1S, so that the first link arm 43 and the second link arm 45 are aligned horizontally (horizontal position tilted at a predetermined angle) and overlap in the height direction. By switching the parallel link mechanism 41 from the storage position (4A) to the lift-down position (4B), the movable basket 3 can be lifted down from the storage position (3A) to the placement position (3B), and packages stored in the luggage compartment 1S can be lowered to the vicinity of the floor F of the delivery destination.

The lift-down mechanism 4 is equipped with a lift drive motor (not shown) that drives the parallel link mechanism 41 between a storage position (4A) and a lift-down position (4B). In this embodiment, when the lift drive motor is driven, the rotation of the drive output shaft (gearhead output shaft) rotates the input shaft (first parallel link shaft 42) attached to the lower end of the first link arm 43 of the parallel link mechanism 41 via a reduction gear train associated with each parallel link mechanism 41, causing the parallel link mechanism 41 to change position between the storage position (4A) and the lift-down position (4B).

The lift-down mechanism 4 is equipped with a lift-down angle encoder 4E that detects the absolute angle of at least one of the first link arm 43 or second link arm 45 that make up the parallel link mechanism 41 (see Figures 5 and 7). In this embodiment, the lift-down angle encoder 4E is provided at the lower end of the first link arm 43 of one of the parallel link mechanisms 41. Based on the detected value (detected angle) by the lift-down angle encoder 4E, the parallel link mechanism 41 is set to reciprocate (reciprocate between the stored position (4A) and the lift-down position (4B)) within a preset target angle range (0 degrees to the target angle).

The lift-down mechanism 4 also includes a storage position limiter (e.g., a photosensor, not shown) that detects the physical stroke limit when the movable car section 3 returns to the storage position (3A), and is configured to stop the lift drive motor when the storage position limiter detects that the movable car section 3 has reached the storage position (3A). The lift drive motor may also be configured to stop when it is detected that the movable car section 3 has reached the storage position (3A) based on the angle detected by the lift-down angle encoder 4E.

The lift-down mechanism 4 is equipped with a drop-off position limiter (e.g., a photosensor, not shown) that detects the physical stroke limit when the movable basket 3 is moved to the drop-off position (3B) near the floor F of the delivery destination, and is set to stop the lift drive motor when the drop-off position limiter detects that the movable basket 3 has reached the drop-off position (3B). The lift drive motor may also be set to stop when it detects that the movable basket 3 has reached the drop-off position (3B) based on the angle detected by the lift-down angle encoder 4E.

After initial operation, this type of lift-down mechanism 4 detects that the value (absolute angle) of the lift-down angle encoder 4E is 0 degrees (origin position) or that the storage position limiter detects that the movable car section 3 is in the storage position (3A). When the lift drive motor is driven in this state, the rotation of the drive output shaft (gearhead output shaft) rotates the input shaft (first parallel link shaft 42) attached to the lower end of the first link arm 43 of the parallel link mechanism 41 via the reduction gear train associated with each parallel link mechanism 41, causing the parallel link mechanism 41 to change position from the storage position (4A) to the lift-down position (4B). At this time, the detection value of the lift-down angle encoder 4E increases.

As shown in Figures 8 to 10, the autonomous delivery robot R of this embodiment is equipped with a priority ground contact portion 8 that contacts the parcel delivery surface F (floor) in preference to the bottom plate portion 31 when the bottom plate portion 31, on which parcels are placed, of the movable basket portion 3 approaches a predetermined distance from the parcel delivery surface F (floor) when the lift-down mechanism 4 lifts the movable basket portion 3 down from the storage position (3A) to the drop-off position (3B). The priority ground contact portion 8 is attached to the bottom plate portion 31 and specifically includes a bracket 81 fixed to the bottom plate portion 31 and an auxiliary wheel 82 rotatably supported at the lower end of the bracket 81. In this embodiment, as shown in Figures 5 and 7, the priority ground contact portion 8 is provided at both ends of the bottom plate portion 31 in the width direction w (both sides of the bottom plate portion 31). In this embodiment, the width direction w of the bottom plate portion 31 is the same direction as the X direction in Figure 1. Furthermore, the direction d (depth direction of the bottom plate portion 31) perpendicular to the width direction w of the bottom plate portion 31 in a plane is the same direction as the Y direction in Figure 1. The priority ground contact portion 8 is fixed to the bottom plate portion 31 in an orientation that protrudes downward from the bottom plate portion 31.

The bottom plate 31, which is integrally provided with the priority contact portion 8 and protruding downward, is configured to rotate about the bottom plate rotation axis 31A located at the end of the bottom plate 31 facing the luggage unloading direction 31x (see Figure 2). Therefore, when the priority contact portion 8 touches the luggage delivery surface F (floor) while the movable basket 3 is being lifted down from the storage position (3A) to the drop-off position (3B) (see Figure 9), and the movable basket 3 is then further lowered toward the drop-off position (3B), the bottom plate 31 rotates about the bottom plate rotation axis 31A toward the luggage unloading direction 31x due to the ground reaction force received by the priority contact portion 8, gradually tilting overall (see Figure 10). In this embodiment, the tilt angle of the bottom plate 31 is set to a predetermined maximum tilt angle suitable for luggage unloading when the movable basket 3 reaches the drop-off position (3B) (see Figures 6 and 7). As a result, by lifting the movable basket section 3 down from the storage position (3A) toward the placement position (3B), the luggage can be slid by its own weight in the inclined direction of the bottom plate section 31 (the same direction as the luggage carrying-out direction 31x, see Figure 2) and discharged onto the luggage delivery surface F (floor).

In this embodiment, as shown in Figure 4, a partially arcuate guide groove 36 that guides the tilting movement of the bottom plate 31 is formed in the upright plate 32 of the movable car section 3, and a guide pin 37 provided on the bottom plate 31 moves along the guide groove 36, thereby ensuring that the movement trajectory of the bottom plate 31 during tilting and when returning from the tilted position to the normal position (a position in which the bottom plate 31 is substantially flat) is constant. A notch 38 is formed in the upright plate 32 of the movable car section 3 to avoid interference with the tilting priority ground contact portion 8 (see Figure 4, etc.).

As shown in Figures 2 and 6, the autonomous delivery robot R according to this embodiment is also equipped with a luggage priority contact portion 48 on the bottom plate portion 31 that has priority contact with the luggage during the finishing pushing process S5, which will be described later. Specifically, the luggage priority contact portion 48 is disposed at the tip (the end portion on the luggage discharge direction 31x side) of the bottom plate portion 31, protruding in the luggage discharge direction 31x. The luggage priority contact portion 48 has a flat pressing surface at its tip that presses the luggage, and is configured so that the entire pressing surface comes into contact with the luggage. A delivery roller 39 for discharging luggage is disposed at the tip of the bottom plate portion 31, and the luggage priority contact portion 48 is disposed in a form that protrudes further in the luggage discharge direction 31x than the delivery roller 39. In this embodiment, the luggage priority contact portions 48 are disposed at a predetermined pitch at three locations on the tip of the bottom plate portion 31: both ends in the width direction w and the center in the width direction w.

The autonomous delivery robot R according to this embodiment is equipped with a force measuring unit 49 that measures the force acting on (applied force to) the parcel priority contact portion 48. The force measuring unit 49 is mounted on each parcel priority contact portion 48. The force measuring unit 49 can be configured using a pressure sensor or strain gauge, but the force measuring unit 49 can also be configured using other appropriate sensors, etc.

As shown in Figures 2, 4 to 10, the outrigger mechanism 5 is a mechanism for supporting the autonomous delivery robot R to prevent it from tipping over when the lift-down mechanism 4 raises or lowers packages. The outrigger mechanism 5 is equipped with a ground arm 51 whose tip contacts the floor F while extending in the direction of lifting down the movable basket 3 from the storage position (3A) toward the placement position (3B). In this embodiment, the ground arm 51 is configured so that a caster 52 provided at the tip of the ground arm 51 contacts the floor F. Specifically, the left and right casters 52 are configured to contact the floor F near both ends of the width direction w of the bottom plate 31 of the movable basket 3 that will contact the floor later, and at positions facing each other across the width direction w of the bottom plate 31 (see Figure 7). The ground arms 51 switch between a storage position (5A) on the outside (outward facing side) of the upright plate sections 32 of the movable car section 3 and not exposed to the outside, and a ground position (5B) inclined from the storage position (5A) to an angle at which the casters 52 at the tips thereof touch the floor F through the opening K of the robot main body 1. The base ends of the ground arms 51 provided on the outside of each upright plate section 32 of the movable car section 3 are connected to a rotation shaft 53, and the pair of ground arms 51 rotate around the rotation shaft 53 between the storage position (5A) and the ground position (5B). The outrigger mechanism 5 is equipped with an outrigger angle encoder 5E that detects the rotation angle of the ground arms 51 from the storage position (5A) to the ground position (5B) (see FIGS. 5 and 7). The detection value (ground contact detection angle) by the outrigger angle encoder 5E when the ground contact arm 51 is rotated from the storage position (5A) to the ground contact position (5B) can be used to set the target angle of the lift-down mechanism 4 (the angle of the drop-off position (3B)). That is, the autonomous delivery robot R according to this embodiment includes a ground contact angle detection unit that detects the ground contact angle at the time when the outrigger mechanism 5 is operated by the control unit C to bring the tip end (castor wheel 52) of the ground contact arm 51, which is the outrigger ground contact portion, into contact with the package delivery surface F (floor), and a lift-down target angle calculation unit C1 that calculates the lift-down target angle of the lift-down mechanism 4 based on the detection value (ground contact detection angle) by the ground contact angle detection unit. In this embodiment, the ground contact angle detection unit is configured using the outrigger angle encoder 5E, and in particular, an absolute encoder that outputs the absolute value of the rotation angle is used as the outrigger angle encoder 5E. The lift-down target angle calculation unit C1 calculates the lift-down target angle of the lift-down mechanism 4 based on the output value of this absolute encoder 5E, and in this embodiment is set to calculate the detection value of the outrigger angle encoder 5E at the time when the tip (castor wheel 52) of the ground contact arm 51, which is the outrigger ground contact portion, touches the load delivery surface F (floor) as the lift-down target angle of the lift-down mechanism 4. The lift-down target angle calculation unit C1 is shown only schematically in Figure 7. Note that in this embodiment, the absolute angle of the outrigger angle encoder 5E is set to the origin position (0 degrees) when the ground contact arm 51 is positioned in the stowed posture (5A) after the initial operation.

The outrigger mechanism 5 is equipped with an outrigger drive motor (not shown). When the outrigger drive motor is driven (FW) with the grounding arm 51 in the stowed position (5A), the rotating shaft 53 (e.g., reduction ratio 1/200) rotates via a gear train. When the outrigger drive motor detects a current equivalent to grounding detection, the outrigger drive motor is stopped and the detection value of the outrigger angle encoder 5E at this point is recorded. After the outrigger drive motor is stopped, the grounding arm 51 is held in the grounding position (5B) by a non-excitation-activated electromagnetic brake contained within the outrigger drive motor.

This type of outrigger mechanism 5 prevents the robot R from tipping over in the roll direction due to a shift in the center of gravity caused by operation of the lift-down mechanism 4 by having the casters 52 touch down on the floor F before the lift-down mechanism 4 operates. When returning the ground contact arm 51 from the ground contact position (5B) to the storage position (5A), the lift-down mechanism 4 moves the movable basket 3 to the storage position (3A), and then the outrigger drive motor is driven (BW). The outrigger drive motor is stopped when the detection value of the outrigger angle encoder 5E reaches 0 degrees (when the outrigger drive motor reaches the origin position corresponding to the storage position (5A)). At this time, the value of the outrigger angle encoder 5E recorded during the previous outrigger operation (the detection value of the outrigger angle encoder 5E when a current equivalent to ground contact detection was detected for the outrigger drive motor and the outrigger drive motor was stopped) is cleared, allowing a new value to be recorded for the outrigger angle encoder 5E when the ground contact arm 51 is rotated from the storage position (5A) to the ground contact position (5B) during the next outrigger ground contact process.

The outrigger mechanism 5 may also be equipped with a first sub-sensor (not shown) that detects the position of the castor 52 attached to the tip of the ground arm 51 (the position of the castor 52 when the ground arm 51 is in the retracted position (5A) or the position of the castor 52 when the ground arm 51 is in the ground position (5B)) to account for errors in the detection value from the outrigger angle encoder 5E when the ground arm 51 is in the retracted position (5A). The first sub-sensor can also detect when the castor 52 has reached a position slightly higher than the designed position of the castor 52 in the ground position (5B), and use this information to determine whether to switch to current detection mode. The outrigger mechanism 5 may also be equipped with a second sub-sensor (not shown) that detects the moment when the castor 52 touches the ground and a large torque is required, and stops the outrigger drive motor. The second sub-sensor can be configured to detect the moment when the castor 52 touches the ground and a large torque is required, and stop the outrigger drive motor at that detection point. An example of the second sub-sensor is an inertial measurement unit (IMU) that provides current detection functionality. Furthermore, when the autonomous delivery robot R is tilted, the outrigger mechanism 5 and lift-down mechanism 4 are also tilted, so if correction of the target angle by the IMU is not required, the second sub-sensor can be omitted.

In the autonomous delivery robot R according to this embodiment, the operation of each of these mechanisms (lift-down mechanism 4, outrigger mechanism 5) is controlled by a control unit C. The operation of the traveling means T is also controlled by a common control unit C.

As shown in FIG. 11 , the autonomous delivery robot R according to this embodiment is equipped with an opposing surface distance detection unit 9 that detects the distance between the robot main body 1 and the surface (opposing surface) W that the robot main body 1 faces in the package removal direction 31x when the robot main body 1 arrives at the delivery destination. The opposing surface W can be a building wall. In this embodiment, distance sensors that serve as opposing surface distance detection units 9 are mounted on the left and right frame portions of the door frame surrounding the opening K of the robot main body 1. In other words, the autonomous delivery robot R according to this embodiment is equipped with two opposing surface distance detection units 9 that detect the distances d1 and d2 between the opposing surface W and the robot main body 1 from different positions. The two opposing surface distance detection units 9 can also be mounted at positions other than the door frame on the robot main body 1 or at appropriate locations on the cart B supporting the robot main body 1. The two opposing surface distance detection units 9 are preferably positioned at the same height and in the same position in the luggage discharge direction 31x, in other words, at positions symmetrical left and right across the center of the width direction w of the bottom plate 31. The distance sensors that make up the opposing surface distance detection units 9 may be selected appropriately from proximity, ultrasonic, infrared, laser, and other types. The opposing surface distance detection units 9 may also be configured to use GPS or image-based ranging technology to detect the distance between the opposing surface W and the robot main body 1.

Furthermore, the autonomous delivery robot R according to this embodiment is equipped with a robot body angle calculation unit C2 that calculates the angle of the robot body 1 with respect to the opposing surface W based on the detection value of the opposing surface separation distance detection unit 9. The robot body angle calculation unit C2 calculates the angle θ of the robot body 1 with respect to the opposing surface W using the following equation 1, where the detection value of one opposing surface separation distance detection unit 9 is "d1," the detection value of the other opposing surface separation distance detection unit 9 is "d2," and the separation distance between the opposing surface separation distance detection units 9 is "Q."
tanθ=(|d2-d1|)/Q...Formula 1
The robot body angle calculation unit C2 is only shown schematically in FIG.

Next, the delivery process (drop-off service) performed by the autonomous delivery robot R according to this embodiment will be explained with reference to the flowchart shown in Figure 12. Below, we will explain the case where one package is placed in the movable basket 3 set in the luggage compartment 1S and then dropped off at the delivery destination.

After the package is loaded into the movable basket 3 of the cargo compartment 1S by an operator such as a delivery worker at the delivery source, and when the package arrives at the delivery destination (destination) (see Figure 1), the autonomous delivery robot R according to this embodiment performs pre-delivery correction processing S01 as pre-processing before executing the delivery process based on a signal that activates the delivery device 2 (including information specifying the package to be delivered).

The pre-delivery correction process S01 corrects the position and posture of the robot R to a preset target position and posture based on the detection values d1 and d2 of the opposing surface distance detection unit 9 and the calculation values of the robot body angle calculation unit C2. Specifically, to correct the distance to the surface (opposing surface, typically a wall) W facing the robot R at the delivery destination (destination) to an appropriate distance (target position) based on the detection values of the opposing surface distance detection unit 9 (distance sensors), the robot R detects the distances d1 and d2 from the opposing surface W using two opposing surface distance detection units 9 (distance sensors) mounted at a predetermined interval Q. The detected values (d1, d2) are sampled while the travel unit T is appropriately driven to move the robot R so that the detected values d1 and d2 are equal and the absolute values of the distances d1 and d2 are the target distance (target position) appropriate for delivery. The target distance (target position) appropriate for delivery can be set appropriately depending on the size of the package, etc. Furthermore, in the pre-delivery correction process S01, while correcting to the target position, the posture of the robot R is corrected to the target posture by sampling the calculated value of the robot body angle calculation unit C2 and appropriately driving the traveling means T to move the robot R or change the orientation of the robot R so that the calculated value becomes the target angle (target posture) suitable for delivery. It is preferable to set the target angle suitable for delivery (the angle θ between the robot R and a reference line WL parallel to the facing surface W shown in FIG. 11) to approximately 0 degrees (0 degrees ± a few degrees).

In this way, during the pre-delivery correction process S01, the control unit C monitors the detection values d1 and d2 of the two opposing surface separation distance detection units 9 (distance measurement sensors) while also monitoring the calculated values of the robot body angle calculation unit C2. The control unit C continues to detect the separation distances d1 and d2 between the robot R and the opposing surface W and calculate the angle θ between the robot R and the opposing surface W for a predetermined period of time. The robot R is then corrected so that these values reach the target values (target distance, target angle), ensuring that the distance between the robot R and the opposing surface W and the robot R's posture relative to the opposing surface W are within the target value range. Examples of the movement mode performed by the travel unit T during this pre-delivery correction process S01 include moving the cart B in the Y direction (crab walking) shown in Figure 1, spin turns, and pivot turns. Figure 13 shows an overall view (side view) of the autonomous delivery robot R upon completion of the pre-delivery correction process S01. Note that in this figure, the mechanisms and parts stored inside the robot body 1 are indicated by hidden lines. Also, the opposing surface W is omitted from the figure.

In the autonomous delivery robot R according to this embodiment, following the pre-delivery correction process S01, the control unit C activates the door opening/closing mechanism of the delivery device 2 to switch the right door D1 and left door D2, which are in the closed state (DA), to the open state (DB) (door opening process S1, see Figure 14). Next, the control unit C activates the outrigger mechanism 5 to place the tip end (castor wheel 52) of the outrigger mechanism 5 on the floor F, which is the package delivery surface (outrigger ground contact process S2, see Figure 15). Figures 14 and 15 are diagrams corresponding to Figure 13 and show the autonomous delivery robot R at the completion of the door opening process S1 and the outrigger ground contact process S2, respectively.

Outrigger ground contact processing S2 is a process for switching the ground contact arm 51 from the storage position (5A) to the ground contact position (5B) by driving the outrigger drive motor of the outrigger mechanism 5 (activating the outrigger mechanism 5). In this embodiment, the detection value (encoder information related to the ground contact angle) from the outrigger angle encoder 5E at the time the ground contact arm 51 is rotated from the storage position (5A) to the ground contact position (5B) is obtained, and the lift-down target angle calculation unit C1 calculates the lift-down target angle of the lift-down mechanism 4 based on this detection value.

Next, in the autonomous delivery robot R according to this embodiment, the control unit C activates the lift-down mechanism 4 to move the movable basket 3 from the storage position (3A) to the delivery position (3B) (lift-down process S3). Figure 16 shows the autonomous delivery robot R at the completion of the lift-down process S3. Note that the movable basket 3 is maintained in the storage position (3A) set on the base frame 20 of the delivery device 2 fixed to the cargo compartment 1S until the lift-down process S3 begins (see Figures 4, 13 to 15).

The lift-down process S3 drives the lift drive motor to change the parallel link mechanism 41 of the lift-down mechanism 4 from the storage position (4A) to the lift-down position (4B), lowering the movable basket 3 to the floor F of the delivery destination. During this process, the control unit C monitors the detection value of the lift-down angle encoder 4E (absolute encoder) and lowers the lift-down mechanism 4 until the detection value of the lift-down angle encoder 4E matches the lift-down target angle of the lift-down mechanism 4 calculated by the lift-down target angle calculation unit C1. Figure 8 shows the lift-down mechanism 4 and outrigger mechanism 5 immediately after the start of the lift-down process S3, when the movable basket 3 has moved a predetermined distance from the storage position (3A) in the baggage unloading direction 31x (when the bottom plate 31 has moved to a position lower than the base frame 20 of the delivery device 2 fixed to the luggage compartment 1S).

As shown in Figure 9, in the autonomous delivery robot R of this embodiment, when the lift-down mechanism 4 lifts down the movable basket section 3 from the storage position (3A) toward the drop-off position (3B), the priority ground contact section 8 attached to the bottom plate section 31 touches the parcel delivery surface F (floor) in preference to the bottom plate section 31 when the bottom plate section 31 of the movable basket section 3 approaches a predetermined distance (in this embodiment, approximately 10 cm from the parcel delivery surface F (floor)) from the parcel delivery surface F (floor). At this point, the detection value of the lift-down angle encoder 4E has not reached the lift-down target angle of the lift-down mechanism 4 calculated by the lift-down target angle calculation section C1. In other words, the movable basket section 3 has not reached the drop-off position (3B). After this point, when the movable basket section 3 is further lifted down toward the drop-off position (3B) (approaching the lift-down target angle), the ground reaction force applied to the lower end of the priority ground contact section 8 (the contact angle received by the priority ground contact section 8) increases as shown in Figure 10. The direction of the ground reaction force is shown schematically by a relatively thick arrow in the figure), and the bottom plate portion 31 rotates around the bottom plate portion rotation axis 31A and gradually tilts in the luggage carrying-out direction 31x. The value detected by the lift-down angle encoder 4E coincides with the lift-down target angle, which is the target value calculated by the lift-down target angle calculation unit C1 (the target value set with reference to the detection value by the outrigger angle encoder 5E at the time when the ground contact arm 51 is rotated from the storage position (5A) to the ground contact position (5B)). When the movable basket 3 is lifted down until it meets the floor, it reaches the drop-off position (3B), at which point the inclination angle of the bottom plate 31 reaches its maximum angle during the drop-off process (see Figures 2, 5, and 6). As a result, the luggage slides under its own weight in the inclination direction of the bottom plate 31 (the same direction as the luggage carrying-out direction 31x), and moves smoothly along rollers 34 provided on the part of the bottom plate 31 that comes into contact with the luggage until part of the bottom (one side of the bottom) comes into contact with the floor F.

During the lift-down process S3, the guide pin 37 on the bottom plate 31 moves along the guide groove 36 formed in the upright plate 32 of the movable basket 3, allowing the bottom plate 31 to move smoothly when tilting, and preventing the bottom plate 31 from shifting in the width direction w while tilting (see Figures 4 to 10).

When the value detected by the lift-down angle encoder 4E reaches the lift-down target angle calculated by the lift-down target angle calculation unit C1, the lift drive motor is stopped and the lift-down process S3 by the lift-down mechanism 4 is terminated. It is also possible to stop the lift drive motor and terminate the lift-down process S3 by the lift-down mechanism 4 when the drop-off position limiter detects that the movable car section 3 has reached the drop-off position (3B).

Following the lift-down process S3, the control unit C activates the travel means T (front wheels T1, rear wheels T2) of the cart B of the autonomous delivery robot R, causing the cart B to move (crab-walk) away from the opposing surface W along the direction of arrow Y in FIG. 1 (evacuation process S4). As a result, the package is completely removed from the movable basket unit 3 onto the package delivery surface F (floor) of the destination. By moving the robot body 1 away from the opposing surface (wall) W in this way, the autonomous delivery robot R enters an evacuation state (backward state) at a predetermined distance from the package. In this embodiment, when executing the pre-drop-and-delivery correction process S01, the control unit C may have already performed a process to steer the travel means T (front wheels T1, rear wheels T2) of the cart B of the autonomous delivery robot R. In this case, the evacuation process S4 following the lift-down process S3 can be executed without executing the stationary steering process again. Furthermore, if the direction of travel of the carriage driven by the traveling means T (front wheels T1, rear wheels T2) is in the direction of arrow X in Figure 1 at the time lift-down process S3 is completed, stationary steering process must be performed before executing retraction process S4.

During the execution of the evacuation process S4, the only parts in contact with the luggage delivery surface F (floor) are the running means (front wheels T1, rear wheels T2), the casters 52 attached to the tip of the ground contact arm 51, and the auxiliary wheels 82 of the priority ground contact portion 8. As the running means (front wheels T1, rear wheels T2), which are the drive wheels, travel, the casters 52 and auxiliary wheels 82 roll (follow) on the luggage delivery surface F (floor) as driven wheels.

In this embodiment, at the end of the evacuation process S4, the package can be completely delivered to the package delivery surface F (floor). In particular, because the above-described processes S1 to S4 are performed after the pre-delivery correction process S01 is performed, the package can be discharged onto the package delivery surface F (floor) at the delivery destination in the appropriate direction relative to the opposing surface (wall) W (a direction in which the package faces directly or nearly directly forward relative to the opposing surface W). Furthermore, a moment in the discharge direction 31x is applied to the package due to the momentum of the package when it is discharged and the difference in level with the package delivery surface F (floor). However, because the pre-delivery correction process S01 is performed in advance, the package is discharged to a position within a predetermined distance of the opposing surface (wall) W, and even if it leans against the opposing surface (wall) W, it will not fall over any further.

Then, immediately after performing the retraction process S4, the autonomous delivery robot R according to this embodiment performs a finishing push process S5, which pushes the package closer to the opposing surface (wall) W. In the finishing push process S5, the robot R first moves in a direction closer to the opposing surface (wall) W by the same distance (retraction movement amount) as the distance moved away from the opposing surface (wall) W during the retraction process S4 after the lift-down process S3. The movement amount in this case is a preset fixed-length feed amount, and a suitable value for the fixed-length feed amount is approximately half the length of the package being handled in the package carry-out direction 31x.

As the autonomous delivery robot R moves toward the opposing surface (wall) W by the fixed feed distance, the parcel priority contact unit 48 comes into contact with the parcel. Further moving the autonomous delivery robot R in the same direction (toward the opposing surface W) causes the robot to begin pushing the parcel toward the opposing surface (wall) W. Because the pushing direction of the parcel priority contact unit 48 is perpendicular (or nearly perpendicular) to the surface of the opposing surface (wall) W in a planar view, the orientation of the parcel can be corrected so that the front-to-back direction (depth direction) of the parcel is perpendicular (or nearly perpendicular) to the surface of the opposing surface (wall) W. In this embodiment, once the robot R has moved (moved forward) toward the opposing surface (wall) W a distance equal to the amount of retraction movement during retraction process S4, the control unit C begins monitoring the change in the measurement value (voltage change) of the force measurement unit 49. When the change in the measurement value of the force measurement unit 49 exceeds a threshold value after the start of the monitoring process, the robot R stops moving (moving forward) toward the opposing surface (wall) W.

As shown in FIG. 17, the point at which the change in the measurement value of the force measurement unit 49 exceeds the threshold value after the monitoring process start point Pt5 is point Pt7, immediately after point Pt6 when the luggage contacts the opposing surface (wall) W, making it possible to identify that the luggage has reached the opposing surface (wall) W. If the luggage is relatively heavy, after point Pt2 when the robot R begins moving forward toward the opposing surface (wall) W immediately after completing the evacuation process S4, the luggage priority contact unit 48 comes into contact with the luggage, and the measurement value of the force measurement unit 49 changes significantly (point P3 in the figure) before the robot R has moved the same distance as the evacuation movement (the distance traveled from Pt1 to Pt2). If the forward movement of the robot R is stopped based on the detection of this change, the luggage cannot be pushed (moved) toward the opposing surface (wall) W simply by contacting the luggage, and the luggage's posture and position cannot be actively corrected or corrected. After the luggage priority contact portion 48 comes into contact with the luggage at point Pt3, the luggage does not move until it exceeds the maximum static frictional force between the luggage and the luggage delivery surface F (floor, platform, etc.), and begins to move at point Pt4 when the maximum static frictional force is exceeded. Therefore, in this embodiment, the start point Pt5 of monitoring the change in measurement value (voltage change amount) is set to point Pt5 when the luggage has finished moving (moving forward) toward the opposing surface (wall) W a distance equal to the retraction movement distance.

On the other hand, if the luggage is relatively light, after point Pt2 when the robot R starts moving forward from the retracted state toward the opposing surface (wall) W, the luggage priority contact unit 48 contacts the luggage at point Pt3, which is less than the amount of movement equal to the retraction movement (the distance traveled from Pt1 to Pt2). However, the measurement value of the force measurement unit 49 does not change significantly (the figure illustrates a case where the measurement value does not change). To appropriately and flexibly perform the finishing push process S5 for luggage of different weights, in this embodiment, the start point Pt5 of monitoring the change in the measurement value (voltage change amount) is set to point Pt5 when the robot has finished moving (forward movement) toward the opposing surface (wall) W a distance equal to the retraction movement distance. Note that the threshold value (threshold value related to the change in the measurement value of the force measurement unit 49) when performing the finishing push process S5 for heavy luggage and the threshold value when performing the finishing push process S5 for light luggage may be different or may be the same value. Additionally, it is preferable to use a threshold value that is based on capturing the amount of change (degree of change) in the measurement value, but it is also acceptable to use a value that is based on capturing the change in the actual measurement value itself.

In this way, by performing the finishing pushing process S5, which pushes the luggage once it has been discharged onto the luggage delivery surface F (floor) to improve its orientation and position based on the opposing surface (wall) W, the luggage discharged from the movable basket section 3 onto the luggage delivery surface F (floor) can be placed in a neat position, with the luggage facing directly towards the opposing surface (wall) W, while remaining in contact with the opposing surface (wall) W without any gaps.

In the finishing push process S5, the robot stops moving toward the opposing surface (wall) W (forward movement) at time Pt7 when the change in the measurement value of the force measurement unit 49 exceeds a threshold value after the monitoring process start time Pt5. Then, to release the pressing force from the luggage priority contact unit 48, it again moves a predetermined distance away from the opposing surface (wall) W (backward movement). The finishing push process S5 is completed at the end of this backward movement. Note that, during the finishing push process S5, the only parts of the robot R in contact with the luggage delivery surface F (floor) are the running means (front wheels T1, rear wheels T2), casters 52, and training wheels 82, just as during the above-mentioned retraction process S4. The casters 52 and training wheels 82 roll (follow) in conjunction with the running movement (forward movement, backward movement) of the running means (front wheels T1, rear wheels T2).

After the finishing push process S5 is completed, the control unit C activates the lift-down mechanism 4 to move the movable basket unit 3, which does not have any luggage placed on it, from the placement position (3B) to the storage position (3A) (lift-down return process S6), and then activates the outrigger mechanism 5 to switch the ground arm 51 from the ground position (5B) to the storage position (5A) (outrigger return process S7), storing each of these mechanisms (lift-down mechanism 4, outrigger mechanism 5) in a space inside the robot main body 1 that is not exposed to the cargo compartment 1S. Note that when the process of storing each mechanism (lift-down mechanism 4, outrigger mechanism 5) in the internal space of the robot main body 1 is executed, the robot R has moved (rearward) to a position a predetermined distance away from the opposing surface (wall) W, so interference between each mechanism (lift-down mechanism 4, outrigger mechanism 5) and the luggage can be avoided.

Following the outrigger return process S7, the door opening/closing mechanism is activated to switch the doors D (right door D1, left door D2) from the open state (DB) to the closed state (DA) (door closing process S8), the control unit C outputs a signal indicating that the drop-off and delivery process has been completed (drop-off and delivery completion signal), and the stationary driving means T (front wheels T1, rear wheels T2) is returned to its original position (stationary return process S9), thereby preparing to head to the next delivery destination or designated robot storage base.

In this way, the autonomous delivery robot R according to this embodiment can complete the provision of a drop-off and delivery service that includes all of the pre-processing, the pre-drop-off and delivery correction process S01, and the finishing process (post-processing), the finishing and pushing process S5.

In this way, with the autonomous delivery robot R according to this embodiment, by operating the lift-down mechanism 4 in a state that allows the lift-down movement of the movable basket 3 by the lift-down mechanism 4 (with the left and right doors D open) and lifting the movable basket 3 down to the drop-off position (3B), the package to be dropped off and stored in the luggage compartment 1S can be moved to the package delivery surface F (floor) of the delivery destination.

In particular, the autonomous delivery robot R according to this embodiment is configured to perform a pre-delivery correction process S01 before operating the lift-down mechanism 4 to move the movable basket 3 to the delivery location (3B) (lift-down movement). The pre-delivery correction process S01 corrects the distance between the robot body 1 and the opposing surface (wall) W to a preset target position based on the detection values of two or more opposing surface distance detection units 9, and corrects the orientation of the robot body 1 relative to the opposing surface (wall) W to a preset target orientation based on the calculation value of the robot body angle calculation unit C2. Therefore, even if the robot body 1 arrives at the delivery destination based on a self-location estimation algorithm (e.g., adaptive Monte Carlo localization (AMCL)), which is an estimation based on probability theory, by performing the pre-delivery correction process S01, it is possible to avoid placing the package at the delivery destination in an incorrect position or orientation. Similarly, even if cumulative deviations due to the characteristics or slope of the ground occur when using odometry based on wheel contact for autonomous driving, the pre-delivery correction process S01 can be eliminated. As shown in FIG. 18 , the target position (target distance, the distance of the robot main body 1 from the opposing surface W) in the pre-placement correction process S01 can be a distance equal to or greater than the sum (H+I'+J') of the amount of the movable basket 3 to be carried out (the distance the movable basket 3 is extended from the surface 10 of the robot main body 1 that faces the opposing surface (wall) W toward the opposing surface (wall) W) and the length of the baggage in the carrying-out direction 31x ("I'" + "J'" in the figure) taking into account the inclination of the baggage. As explained in the figure, the maximum value of "I'" is I cos θ, and "I'" can also be set to a value smaller than I cos θ. Of course, the target position (target distance) can also be set using an arithmetic expression other than "H+I'+J'". Then, by correcting the distance of the robot main body 1 from the opposing surface W to the target position (target distance) using the pre-delivery correction process S01, even if the momentum or the eccentricity of the center of gravity of the luggage itself causes the luggage to tip over in the luggage carrying-out direction 31x when it is carried out of the movable basket section 3, the luggage can be prevented from hitting or leaning against the opposing surface (wall) W and tipping over.

Furthermore, with the autonomous delivery robot R according to this embodiment, the lift-down mechanism 4 is activated to lift down the movable basket 3 to the placement position (3B), and then the robot enters a retreated state (retracted state) at a predetermined distance from the package (i.e., executes the above-mentioned retreat process S4), thereby allowing the entire package to be placed completely on the package delivery surface F. Furthermore, by executing a finishing push process S5 in which the robot moves (forward) from the retreated state toward the opposing surface (wall) W to push the package toward the opposing surface (wall) W, the robot can place the package completely on the package delivery surface F. The package will be pushed by the tip of the movable basket 3 (the end on the package discharge direction 31x side) in a direction approaching the opposing surface (wall) W while maintaining the angle of the robot main body 1 at the time the pre-delivery correction process S01 is completed. Even if a deviation occurs in the delivery position or delivery posture of the package when it is discharged from the movable basket 3 due to the smoothness of the package's bottom surface (rolling surface) or an eccentric center of gravity of the package, the package can be moved to a predetermined delivery position in contact with or close to the opposing surface (wall) W while correcting its delivery posture to a posture facing directly at the opposing surface (wall) W.

Furthermore, with the autonomous delivery robot R according to this embodiment, even if a lightweight package is not completely ejected from the movable basket 3 and is dragged backward to a certain extent by the robot R's backward movement (evacuation process S4), the finishing push process S5 can be executed to correct the misalignment and place the package in the correct position, tightly against the opposing surface (wall) W.

With the autonomous delivery robot R according to this embodiment, there is no need to install a mechanism or posture sensing means in the luggage compartment 1S within the robot body 1 to guide the package in advance according to its size so that its loading posture does not change. This avoids a complex structure and also prevents the delivery source from having to perform unnecessary work when loading the package into the luggage compartment 1S.

In particular, the autonomous delivery robot R according to this embodiment is equipped with a luggage priority contact unit 48 that makes priority contact with the luggage during the finishing push process S5, and a force measurement unit 49 that measures the force acting on the luggage priority contact unit 48 that has made contact with the luggage. Therefore, it is possible to detect that the luggage has reached the opposing surface (wall) W based on the event in which the measurement value of the force measurement unit 49 exceeds a predetermined threshold during the finishing push process S5. Then, by stopping the process of pushing the luggage toward the opposing surface W when the measurement value of the force measurement unit 49 exceeds the predetermined threshold, the luggage can be moved to an appropriate position close to the opposing surface (wall) W. In this embodiment, the luggage priority contact portion 48 is provided at the front end (end on the luggage unloading direction 31x side) of the bottom plate portion 31 of the movable basket portion 3, protruding further forward (in the luggage unloading direction 31x) than other components and parts. Therefore, immediately after the evacuation process S4 is completed, the movable basket portion 3, which has been lifted down to the placement position (3B), does not need to be returned to the storage position (3A) but instead the robot R can be moved toward the opposing surface (wall) W in the same position (with the movable basket portion 3 remaining in the placement position (3B)) to execute the finishing push process S5. This simplifies the process and shortens the processing time compared to an embodiment that requires the movable basket portion 3 to be returned from the placement position (3B) to the storage position (3A) immediately after the evacuation process S4 is completed.

In the autonomous delivery robot R according to this embodiment, during the finishing pushing process S5, monitoring of the measurement value of the force measurement unit 49 begins when the robot body 1 is moved (forward) toward the opposing surface (wall) W by the same distance as the distance moved by the traveling means T in a direction away from the opposing surface (wall) W (retreat distance; a distance equal to the maximum value of the package's dimensions along the package unloading direction 31x). Therefore, because monitoring of the measurement value of the force measurement unit 49 does not begin at time Pt3, when the package begins to contact the opposing surface (wall) W before it reaches the opposing surface (wall), any change in the measurement value at that time is ignored. Therefore, after time Pt5 when monitoring of the measurement value of the force measurement unit 49 begins, it is possible to reliably detect that the package has reached the opposing surface (wall) W based on the first change in the measurement value. When the finishing pushing process S5 is stopped based on this change, the package can be placed in contact with or close to the opposing surface (wall) W.

As described above, the autonomous delivery robot R according to this embodiment significantly increases the probability of discharging packages in the target position on the package delivery surface F (floor) in the target posture. Furthermore, it can adjust the posture of the package discharged on the package delivery surface F (floor) and the gap distance between the package and the opposing surface (wall) W to the appropriate posture and distance (position), allowing it to perform drop-off and delivery processing with the same quality as if the package were delivered by a delivery person. Furthermore, the autonomous delivery robot R according to this embodiment can also carry multiple packages. In this case, the drop-off and delivery processing can be performed appropriately by placing only the packages to be dropped off on the bottom plate 31 of the movable basket 3 in the luggage compartment 1S of the robot body 1 and then lifting down the movable basket 3. This allows packages to be delivered to multiple destinations in a single delivery round in the appropriate posture, close to the opposing surface (wall) W. Furthermore, the autonomous delivery robot R according to this embodiment can flexibly combine regular delivery and drop-off delivery, and by achieving the various effects described above, it can solve all of the current problems, such as an increase in parcels, an increased workload for delivery drivers, a driver shortage, and a demand for non-contact delivery.

The present invention is not limited to the above-described embodiment. For example, the above-described embodiment illustrates an embodiment in which three luggage priority contact areas are arranged at a predetermined pitch on the tip of the bottom plate. However, the number of luggage priority contact areas may be two or less or four or more, and the locations of the luggage priority contact areas can be selected and changed as appropriate. Therefore, the present invention also includes configurations in which luggage priority contact areas are provided on locations other than the bottom plate of the movable basket, such as on a pair of left and right upright plates; configurations in which luggage priority contact areas are provided on locations other than the movable basket, such as appropriate locations on the link mechanism that constitutes the lift-down mechanism; or configurations in which luggage priority contact areas are provided on appropriate locations on the door or the trolley. The material and shape of the luggage priority contact areas can be selected and changed as appropriate. Furthermore, instead of using a dedicated luggage priority contact area (the above-described luggage priority contact area 48) to form the luggage pushing means (pushing means), it is also possible to employ a configuration in which the tip of the movable basket (the end on the luggage unloading direction side) itself functions as the pushing means (luggage priority contact area).

The timing of the finishing push process, which moves luggage toward the opposing surface after the movable basket section has been lifted down from the storage position to the delivery position, is not limited to immediately after the evacuation process described in the above embodiment. For example, the present invention also includes a mode in which the finishing push process is performed immediately after the lift-down return process, a mode in which the finishing push process is performed immediately after the outrigger return process, or a mode in which the finishing push process is performed immediately after the door closing process. Even in a mode in which the finishing push process is performed immediately after the outrigger return process or immediately after the door closing process, the finishing push process can be performed using a push means by having the part of the door or cart that faces the opposing surface itself function as the push means (luggage priority contact portion), or by adopting an aspect in which the push means (luggage priority contact portion) is configured by a dedicated component mounted on the door or cart.

The present invention also includes embodiments that do not include a force measuring unit that measures the force acting on the luggage priority contact portion. In this case, in the finishing push process, the distance moved toward the facing surface from a state where the luggage has been retracted from the opposing surface and luggage during the retraction process can be set to the same distance (fixed feed amount) as the retraction movement distance during the retraction process. It is preferable to set the fixed feed amount to a value greater than the maximum length in the luggage discharge direction of the luggage size being handled. Even in this finishing push process using fixed feed, if the luggage has a similar length in the luggage discharge direction, the luggage's posture and the distance between the luggage and the opposing surface can be corrected to the appropriate posture and distance by pushing the luggage with the luggage priority contact portion.

On the other hand, if the finishing push process is performed while detecting the force (or pressure) acting on the luggage priority contact portion based on the measurement value of the force measuring unit, as in the above-mentioned embodiment, luggage of different sizes can be flexibly handled, and the luggage's orientation can be corrected to the correct direction (facing directly toward the opposing surface), and the luggage can be placed in close contact with or close to the opposing surface at the delivery destination.

In the above-described embodiment, a wall was used as an example of an opposing surface in the present invention. However, the opposing surface in the present invention, i.e., the "surface (opposing surface) that the robot main body faces in the direction of package removal when it arrives at the delivery destination," does not necessarily have to be an entirely flat surface like a "wall," but also includes surfaces with partially flat surfaces. Specific examples other than "walls," such as the exterior and interior walls of a building, include outdoor structures (exteriors), such as walls, fences, walls, and gates; pillars (pillars and beams of a house); poles (parking lot poles, etc.); legs of desks and tables; box-shaped items (trash cans, shelves, pallets, chests of drawers, etc.); stairs (front door stairs, stairs inside a house, etc.); delivery lockers; elevators; garages; and other suitable sensors. The opposing surface distance detection unit and force measurement unit that detect the distance between the opposing surface and the robot main body are not limited to distance sensors, pressure sensors, and strain gauges, but may also include other suitable sensors.

The specific calculation process content (calculation formula) of the robot body angle calculation unit, which calculates the angle of the robot body relative to the opposing surface based on the detection value of the opposing surface distance detection unit, can be selected or changed to be optimal as appropriate depending on the number of opposing surface distance detection units, their installation locations, etc.

In addition, the above-described embodiment exemplifies a mode in which, in order to completely remove (move) the parcel from the movable basket to the parcel delivery surface, a retraction process is performed following the lift-down process, and the entire robot is then moved (forward) toward the opposing surface from a state where it is retracted from the opposing surface and the parcel, thereby performing a finishing push process. This is not limited to this mode. If the autonomous delivery robot can perform an appropriate complete parcel discharge process instead of a retraction process, it can be configured to perform a finishing push process in which, following the complete parcel discharge process, the parcel that has been moved from the movable basket to the parcel delivery surface is pushed toward the opposing surface. Alternatively, if the parcel can be completely removed (moved) from the movable basket to the parcel delivery surface upon completion of the lift-down process, the finishing push process can be performed at an appropriate timing after completion of the lift-down process. In these cases, the retraction process in which the entire robot is moved away from the opposing surface and the parcel prior to performing the finishing push process can be omitted. Examples of complete luggage ejection processes include a process in which luggage placed on the bottom plate of the movable basket in the placement position is moved toward the opposing surface (in the luggage removal direction) using a forced movement means (such as an electric transport conveyor or roller conveyor attached to the bottom plate of the movable basket, or a pressing part that moves from the rear side of the movable basket toward the front), thereby completely moving the luggage from the movable basket to the luggage delivery surface; and a process in which only the bottom plate of the movable basket in the placement position slides away from the opposing surface (the bottom of the movable basket temporarily comes out), thereby completely moving the luggage from the movable basket to the luggage delivery surface.

By using a non-stationary driving means or a differential two-wheel type that can perform spin turns with the left and right wheels rotating in opposite directions, forward and backward movement, pivot turns, etc., it is possible to realize an autonomous delivery robot that can provide the same drop-off delivery service as described above.

The doors of the autonomous delivery robot of the present invention are not limited to double-door doors, but can also be shutter-type doors, foldable doors, or doors (upper-type doors) that can be switched to an open state by rotating the closed door around an actuation rotation axis installed horizontally at the top end of the door.

For example, in the above-described embodiment, a configuration was given in which the bottom plate of the movable basket section tilts during the lift-down process using a priority ground contact area, with the bottom plate section tilting due to a ground reaction force acting on the priority ground contact area. However, instead, a configuration in which the bottom plate of the movable basket section tilts via a mechanical link member that is linked to the movement of the lift-down mechanism accompanying the lift-down operation of the package can be adopted. In either case, by tilting the bottom plate section during the lift-down process, a delivery robot can be realized that sends packages to be left on the package delivery surface. Furthermore, the bottom plate of the movable basket section, which is in a horizontal or nearly horizontal position when the lift-down process is completed, can be tilted electrically or by an appropriate link mechanism after the lift-down process is completed, so that the packages to be left on the package delivery surface can be sent.

When using a configuration in which an electric transport conveyor or roller conveyor is installed on the bottom plate of the movable basket, connecting a non-excited brake to the transport conveyor, roller conveyor, etc. can prevent or suppress the movement of luggage in the cargo compartment due to tilting of the robot body or acceleration in each direction while traveling.

In the present invention, the lift-down mechanism may be a hydraulic lift that raises and lowers the movable basket between the storage position and the delivery position. When using a hydraulic lift to raise and lower the movable basket between the storage position and the delivery position, an actuator that raises and lowers the movable basket and an actuator that moves the movable basket from the luggage compartment toward the outside through the opening are required.

The robot body in this invention is not limited to being box-shaped, but may be cylindrical or have any other shape with an appropriate internal space. The size of the internal space and cargo compartment can be modified as appropriate depending on specifications, etc. Furthermore, the size of the opening that can be opened and closed by a door can also be modified as appropriate. In particular, in the above-described embodiment, an opening is provided on only one side of the robot body, and this opening is opened and closed by a door. However, depending on the size of the internal space and cargo compartment of the robot body, openings may be provided on both sides of the robot body, and each opening may be opened and closed by a door. In this case, if the movable basket section is configured to be movable from the storage position to the delivery position through each opening by a lift-down mechanism, this increases the options for the direction in which the package can be carried out, which is expected to contribute to the efficiency of delivery work. Furthermore, openings may be provided on either or both of the front and back sides of the robot body, and the openings may be opened and closed by a door.

The autonomous delivery robot of the present invention may be configured with multiple delivery devices mounted on the robot body, or with multiple robot bodies mounted on a common cart, each equipped with a delivery device. With such a configuration, increasing the number of delivery devices can accommodate an increase in the number of delivery destinations (an increase in packages to be delivered).

In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

1...Robot body 1S...Luggage compartment 2...Delivery device 3...Movable basket section 31...Bottom plate section (3A)...Storage position (3B)...Delivery position 4...Lift-down mechanism 48...Luggage priority contact section (push-out means)
49...force measuring unit 9...opposing surface separation distance detection unit C...control unit C2...robot main body angle calculation unit R...autonomous traveling delivery robot T...traveling means

Claims (3)

An autonomous delivery robot comprising: a traveling means capable of autonomous traveling; a robot body having a part of its internal space set as a cargo compartment; a delivery device mounted on the robot body; and a control unit that executes at least a delivery process;
The delivery device includes:
a movable basket portion capable of accommodating luggage;
a lift-down mechanism that lifts down the movable basket from a storage position where the entire movable basket is stored in the luggage compartment to a placement position where at least a portion of a bottom plate of the movable basket is in contact with or close to a luggage delivery surface of a delivery destination;
two or more opposing surface distance detection units that detect the distance between the robot body and an opposing surface, which is a surface that faces the robot body in the direction of carrying out the luggage when the robot body arrives at the delivery destination, from mutually different positions;
a robot body angle calculation unit that calculates an angle of the robot body with respect to the opposing surface based on a detection value of the opposing surface separation distance detection unit,
a pre-delivery correction process for correcting the position and posture of the robot body to a preset target position and posture based on the detection value of the opposing surface separation distance detection unit and the calculation value of the robot body angle calculation unit, before the control unit operates the lift-down mechanism to execute the delivery process;
This autonomous delivery robot is characterized in that, after the lift-down mechanism is activated to lift down the movable basket section from the storage position to the delivery position, it performs a finishing pushing process to push the parcels that have been moved from the movable basket section to the parcel delivery surface toward the opposing surface. a luggage priority contact portion that contacts the luggage preferentially during execution of the finishing pressing process;
a force measuring unit that measures a force acting on the luggage priority contact portion that is in contact with the luggage,
The autonomous delivery robot of claim 1 is configured to stop the finishing press process when the measurement value of the force measuring unit exceeds a predetermined threshold during the finishing press process. the finishing pressing process is a process performed following a retreat process in which the traveling means moves the robot body in a direction away from the opposing surface,
The autonomous delivery robot of claim 2 is configured to start monitoring the measurement value of the force measuring unit after the finishing pushing process has been performed by moving the robot toward the opposing surface a distance equal to the evacuation movement distance during the evacuation process.