JP7623568B2 - Mobile robot with robotic arm - Google Patents

Description

The present invention relates to a mobile robot with a robot arm.

In order to automate the movement of goods within facilities such as factories, warehouses, and hospitals, the introduction of automated guided vehicles is progressing. As for the method of automatic driving for automated guided vehicles, autonomous mobile automated guided vehicles are becoming mainstream as opposed to the conventional route-guided type due to recent improvements in information processing capabilities and surrounding information gathering technology. Furthermore, automated guided vehicles are also being equipped with robotic arms to automate loading and unloading.

For mobile robots with robotic arms (i.e., mobile robots that run autonomously with a robotic arm mounted on a mobile platform that realizes the robot's mobility), it is necessary to ensure safety in terms of both the movement of the vehicle body and the movement of the robotic arm.

In this regard, it has been proposed to provide non-contact type obstacle detection sensors for the carriage, such as ultrasonic sensors and optical sensors, at the front and rear of a moving platform called a transport carriage, with detection areas set horizontally, and to provide non-contact type obstacle detection sensors for the arm around the moving platform, pointing diagonally upward, and to set the obstacle detection distance of the obstacle detection sensor for the carriage longer than the obstacle detection distance of the obstacle detection sensor for the arm (Patent Document 1). According to this mobile robot, when an obstacle such as a person, surrounding objects, or another mobile robot is present ahead in the direction of travel, the obstacle detection sensor for the carriage detects the obstacle before the obstacle detection sensor for the arm detects it, so that the moving platform can be stopped before the obstacle detection sensor for the arm detects the obstacle. Furthermore, if the obstacle detection sensor for the carriage detects an obstacle but the obstacle detection sensor for the arm does not detect an obstacle, no safety operation is performed for the robot arm, so that the robot arm can continue to work even after the moving platform has stopped until the obstacle detection sensor for the arm detects an obstacle. Therefore, it is said that work can be carried out efficiently using the robot arm.

It has also been proposed to use the robot's operating program to restrict the amount of the robot that extends beyond the planar projection range of a movable platform known as a mobile trolley, and to restrict the robot's operating range using hardware such as partitions surrounding the workbench (Patent Document 2).

Japanese Patent Application Publication No. 9-300252 JP 2018-111180 A

However, as described in Patent Document 1, if the detection ranges and directions of the cart obstacle detection sensor and the arm obstacle detection sensor are made different, and the robot arm is allowed to continue working in a state where the cart obstacle detection sensor detects an obstacle but the arm obstacle detection sensor does not, there is a risk that the robot arm will collide with the obstacle if the obstacle approaches the robot arm quickly, and for example, a person working around the robot arm may be injured.

In addition, as described in Patent Document 2, even if the operating range of the robot arm is restricted by the amount that it protrudes from the planar projection range of the moving platform, it is not possible to prevent people from entering the operating range, and there is a risk of injury to people who enter the operating range.

In order to ensure safety, it is conceivable to set up the non-contact sensor on the mobile platform at a safe distance away from the restricted space in which the robot arm is permitted to operate, thereby forming a safe protected space. In this case, if the detection area of the non-contact sensor that detects the intrusion of obstacles forms a horizontal plane, a safety distance of 1 to 3 m is normally required to prevent contact between a person and the robot arm, but if the detection area forms a vertical plane extending perpendicular to the floor surface, the safety distance can be shortened to around 0.5 to 1 m.

However, even if a non-contact sensor is installed on the mobile platform so that the detection area forms a vertical plane, if the non-contact sensor is installed a safe distance away from the restricted space of the robot arm, there is a risk that the non-contact sensor will impede the movement of the mobile platform, making it impossible to pass through a passage of the previous width. In addition, when the mobile platform turns a corner, the contact sensor may come into contact with surrounding structures, causing damage to the non-contact sensor and surrounding structures.

The objective of this invention is to provide a technology for a mobile robot in which a robot arm is mounted on a mobile platform, in which a non-contact sensor is used to form a safeguard space, thereby ensuring safety for the surroundings when the mobile platform is moving or the robot is working, and preventing the non-contact sensor from becoming an obstacle to the movement of the mobile platform.

The inventors have come up with the idea that in order to ensure the safety of the surroundings while allowing the mobile robot with a robot arm to move smoothly, it is effective to make the horizontal position of the non-contact sensor movable when installing a non-contact sensor on a mobile robot with a robot arm, the robot arm being mounted on a vehicle body that serves as a moving platform, so that the detection area for detecting the intrusion of obstacles forms a vertical plane, and to form a safe protected space in the detection area. This led to the completion of the present invention.

That is, the present invention provides a mobile robot with a robot arm, the robot arm being mounted on a vehicle body and having a non-contact sensor,
The non-contact sensor has a detection area that forms a vertical plane, the detection area forms a safe protection space for the robot arm, and the horizontal position of the non-contact sensor is movable, thereby providing a mobile robot with a robot arm.

The present invention also provides a method for forming a safeguard space for a mobile robot with a robot arm, the robot arm being mounted on a vehicle body, by using a non-contact sensor provided on the mobile robot with the robot arm, the method comprising the steps of:
The detection area of the non-contact sensor is a vertical plane, and the horizontal position of the non-contact sensor is made movable, thereby providing a method for forming a safeguard space in which the size of the safeguard space can be varied.

In this specification, the term "detection area" does not necessarily mean the entire range in which the non-contact sensor itself is capable of detecting the presence of an object, but may also mean a portion of that entire range that is determined by the user or designer using software or the like.

According to the mobile robot with a robot arm of the present invention, the detection area of the non-contact sensor that forms the safeguard space forms a vertical plane, and the horizontal position of the non-contact sensor is movable. Therefore, for example, when the vehicle body is moved while the robot arm is stopped working, if the non-contact sensor is installed near the vehicle body, the non-contact sensor is unlikely to impede the movement of the mobile robot with a robot arm even if the passage width is narrow. Also, when the vehicle body is stopped and the robot arm is made to work, the non-contact sensor is installed away from the outer periphery of the vehicle body, so that the safety required for the robot arm to work can be ensured.

In this way, the present invention makes it possible to ensure a safe protective space using non-contact sensors while preventing the non-contact sensors from interfering with the movement of a mobile robot with a robot arm.

FIG. 1A is a top view of a mobile robot 1A with a robot arm in which the robot arm is at rest and a non-contact sensor is located near the vehicle body. FIG. 1B is a front view of the mobile robot with robot arm 1A in which the robot arm is not in operation and the non-contact sensor is located near the vehicle body. FIG. 1C is a side view of the mobile robot with robot arm 1A in which the robot arm is not in operation and the non-contact sensor is located near the vehicle body. FIG. 2A is a top view of the mobile robot 1A with a robot arm when the robot arm is in operation and the non-contact sensor is away from the vicinity of the vehicle body. FIG. 2B is a front view of the mobile robot with robot arm 1A with the robot arm in operation and the non-contact sensor away from the vicinity of the vehicle body. FIG. 2C is a side view of the mobile robot with a robot arm 1A with the robot arm in operation and the non-contact sensor away from the vicinity of the vehicle body. FIG. 3A is a top view of the mobile robot 1A with a robot arm when the robot arm is in operation and the non-contact sensor is away from the vicinity of the vehicle body. FIG. 3B is a front view of the mobile robot with robot arm 1A with the robot arm in operation and the non-contact sensor away from the vicinity of the vehicle body. FIG. 3C is a side view of the mobile robot with a robot arm 1A with the robot arm in operation and the non-contact sensor away from the vicinity of the vehicle body. FIG. 4 is an explanatory diagram of the passage of the mobile robot with robot arm 1A. FIG. 5 is a front view of the mobile robot with robot arm 1A storing an article in a transport box. FIG. 6A is a top view of a mobile robot with a robot arm 1B in which the robot arm is not performing any work and the non-contact sensor is located near the vehicle body. FIG. 6B is a front view of the mobile robot with robot arm 1B in which the robot arm is not in operation and the non-contact sensor is located near the vehicle body. FIG. 6C is a side view of the mobile robot with robot arm 1B in which the robot arm is not performing any work and the non-contact sensor is located near the vehicle body. FIG. 7A is a top view of a mobile robot 1B with a robot arm when the robot arm is in operation and the non-contact sensor is away from the vicinity of the vehicle body. FIG. 7B is a front view of the mobile robot with robot arm 1B in which the robot arm is in operation and the non-contact sensor is away from the vicinity of the vehicle body. FIG. 7C is a side view of the mobile robot with robot arm 1B in which the robot arm is in operation and the non-contact sensor is away from the vicinity of the vehicle body. FIG. 8A is a front view of a mobile robot with a robot arm 1C. FIG. 8B is a side view of the mobile robot with a robot arm 1C. FIG. 9A is a top view of a mobile robot 1D with a robot arm in which the robot arm is not performing any work and the non-contact sensor is located near the vehicle body. FIG. 9B is a front view of the mobile robot 1D with a robot arm in which the robot arm is not in operation and the non-contact sensor is located near the vehicle body. FIG. 9C is a side view of a mobile robot 1D with a robot arm in which the robot arm is not working and the non-contact sensor is located near the vehicle body. FIG. 10A is a top view of a mobile robot 1D with a robot arm in which the robot arm is in operation and the non-contact sensor is away from the vicinity of the vehicle body. FIG. 10B is a front view of the mobile robot 1D with a robot arm in operation and the non-contact sensor away from the vicinity of the vehicle body. FIG. 10C is a side view of the mobile robot 1D with a robot arm in operation and the non-contact sensor away from the vicinity of the vehicle body.

The present invention will now be described in detail with reference to the drawings. Note that the same reference numerals in each drawing represent the same or equivalent components.

<Overall configuration of mobile robot with robot arm>
Fig. 1A is a top view of a mobile robot 1A with a robot arm according to an embodiment of the present invention, in which the robot arm is at rest and non-contact sensors 80A, 80B, and 80C are located near the vehicle body on the outer periphery of the vehicle body, Fig. 1B is a front view thereof, and Fig. 1C is a side view thereof. Fig. 2A is a top view of the mobile robot 1A with a robot arm in a state where the robot arm is working and the non-contact sensors 80A, 80B, and 80C are located away from the vehicle body, Fig. 2B is a front view thereof, and Fig. 2C is a side view thereof.

This mobile robot with robotic arms 1A moves autonomously (i.e., using an unmanned guided vehicle system) from a waiting point to a work point and performs a specified task at the work point. A dual-arm robot 10 equipped with two vertical articulated robot arms 11 is mounted on the vehicle body 2 of the mobile robot with robotic arms 1A. A warning light 14 is provided on the shoulder of the dual-arm robot 10.

The vehicle body 2 is also provided with horizontal movement devices 70A and 70B having sliders 71 capable of moving horizontally from the left and right sides of the vehicle body 2 toward the outside of the vehicle body and returning to their original position, and a horizontal movement device 70C having a slider 71 capable of moving horizontally from the rear of the vehicle body 2 toward the outside of the vehicle body and returning to its original position. These horizontal movement devices 70A, 70B, and 70C are fitted with laser scanners as non-contact sensors 80A, 80B, and 80C with their detection directions facing upward. As a result, the detection areas Da and Db of the non-contact sensors 80A and 80B located on the left and right sides of the vehicle body 2 are vertical planes parallel to the sides of the vehicle body 2, and the detection area Dc of the non-contact sensor 80C on the rear side of the vehicle body 2 is a vertical plane parallel to the rear of the vehicle body. Since the laser scanner can set the detection area in a vertical plane to a predetermined shape, each laser scanner is set so that each detection area Da, Db, and Dc forms a safe protection space Sa for the mobile robot 1A with a robot arm (Figure 1A).

In the present invention, the vertical plane is not limited to a plane strictly parallel to the direction of gravity, but may be any plane that is substantially vertical.

In addition, in the present invention, the installation position of the non-contact sensor is not limited to the above example, and can be changed as appropriate depending on the arrangement of structures around the passageway along which the mobile robot with a robot arm travels and the work area. For example, the detection area of the non-contact sensor can be positioned so as to surround the vehicle body from all four sides, i.e., front, rear, left and right, by providing the slider 71 of the horizontal movement device so that it can move toward the outside of the vehicle body from all four sides, i.e., front, rear, left and right.

In addition, in the present invention, the method of installing a non-contact sensor so that its horizontal position can be moved is not limited to using a horizontal movement device. For example, the non-contact sensor may be attached to a rotating movement device (Figures 9A to 10C) as described below.

A workbench 50 is provided in front of the dual-arm robot 10 on the vehicle body 2. The vehicle body 2 may also be provided with a loading platform, a transport box 60, etc., used for transporting luggage (Figure 5).

(Autonomous Driving System)
The vehicle body 2 is equipped with an autonomous driving system so that the mobile robot 1A with a robot arm can automatically travel through a predetermined passage to a pick point, a work point, a place point, a waiting point, etc. The method of estimating the self-position in the autonomous moving type and the method of improving the accuracy are not particularly limited, and examples thereof include a laser ranging method, a laser SLAM (Simultaneous Localization And Mapping) method, and an image SLAM method. In addition, a laser range finder (LRF), also known as Lidar (Light Detection and Ranging), is generally used to detect the position distribution of surrounding objects. As an example of improving the accuracy of the autonomous driving, fixed point correction using an RFID, a QR code (registered trademark), a magnet, etc. may be performed.

In the present invention, the method of automatic driving is not limited to the autonomous movement method, and may be, for example, a route guidance method, a following method, etc. Among these, examples of the route guidance method include electromagnetic guidance method, optical guidance method, magnetic guidance method, magnetic material guidance method, etc., and an appropriate method is selected based on the available sensors and floor constraints.

(Non-contact sensor)
As described above, in this embodiment, laser scanners are used as the non-contact sensors 80A, 80B, and 80C, but the type of non-contact sensor is not particularly limited in the present invention. For example, in addition to laser scanners, light curtains, area sensors, ultrasonic sensors, infrared sensors, etc. can be used. From the standpoints of safety and reliability, laser scanners and light curtains are preferable, and further, laser scanners are preferable because they are easy to install since the light emitting position and the light receiving position are roughly the same position, and they can be installed compactly.

In addition, with regard to light curtains and laser scanners, highly reliable devices that are designated PLd, PLe, SIL2, SIL3, etc. in the ISO and SIL standards are called safety light curtains and safety laser scanners, respectively. In the present invention, it is preferable to use a safety laser scanner as the laser scanner.

Safety laser scanners generally use a radial laser beam for scanning, and are capable of 270° horizontal scanning, including 45° to the left and right and 45° to the front and sides, as well as the rear. In addition, the detection distance can be set as desired, and the shape of the detection area can be determined as desired.

It is also possible to set multiple detection zones on a single safety laser scanner. Several detection zones can be set in advance, and the detection zones can be switched depending on the task of the robot arm. Detection signals for each set detection zone can be output from multiple independent terminals, making it possible to achieve high reliability in detecting obstacles in each detection zone.

In the present invention, the non-contact sensor is attached to the vehicle body so that the detection area of the non-contact sensor forms a vertical plane. That is, the non-contact sensor is attached so that the detection element such as the laser light of a laser scanner or the ultrasonic wave of an ultrasonic sensor scans a vertical plane, or the arrangement surface of the laser light of a laser curtain or the like forms a vertical plane. This is for the following reason. If the detection area forms a horizontal plane, when a person enters the detection area, only the torso of the person is often detected. Therefore, in calculating the safety distance (JIS B 9715), it is necessary to take into account the length of the person's arm extending in the direction of the robot arm, which is the source of danger, and a safety distance of 1 to 3 m is usually required. It is customary to take the length of a person's arm as 0.85 m, and the safety distance is calculated by adding the distance obtained by multiplying the total of the sensor's detection time and the stop time of the device such as a robot by the approach speed of the person. In contrast, if the non-contact sensor is installed so that the detection area forms a vertical plane, it becomes unnecessary to take the length of the person's arm into account in the calculation of the safety distance, and the safety distance can usually be shortened to about 0.5 to 1 m.

In this way, by making the detection area a vertical plane, the safety distance can be narrowed compared to if it were a horizontal plane, and the movement of the robot arm is less likely to be slowed down or stopped even if a person is close to the robot arm. Therefore, by making the detection area a vertical plane, the work efficiency of the robot arm can be improved.

Here, the safety distance generally refers to the appropriate distance between a protective structure and a danger zone to prevent the upper and lower limbs of machinery from reaching the danger zone (JIS B 9718), and in the case of a mobile robot with a robot arm, it is the distance that makes it possible to make these hazards non-hazardous before a person comes into contact with the robot arm, end effector, or workpiece held by the end effector.

As shown in Figures 2A to 2C, the position obtained by adding the safety distance L to the restricted space Sr is the safe protection space Sa. If an obstacle such as a person enters the safe protection space formed by the non-contact sensor, the robot arm is controlled by the program of the robot arm's control device to slow down or stop its movement. Therefore, the safety of people around the robot arm is guaranteed by being outside the safe protection device.

The safeguard space is defined as the surrounding safeguard (JIS B 8433-1). More specifically, in addition to safeguard devices such as non-contact sensors around the robot arm, the safeguard space is also formed by mechanical guards such as fences and surrounding structures in the work environment.

The restricted space Sr is a space that is restricted so that the movement of the hazardous robot arm, end effector, and workpiece held by the end effector cannot be exceeded. JIS B 8433-1 defines the restricted space as "a part of the maximum space, and a space restricted by a restricting device that sets a limit that must not be exceeded." Here, "maximum space" is defined in JIS B 8433-1 as "the space that the robot's moving parts can reach, as determined by the manufacturer, plus the space that the end effector and workpiece can reach."

The restricted space Sr is formed by restrictions on the robot arm's movement imposed by the robot arm's control device program and mechanical restrictions. The restrictions on the robot arm's movement imposed by the control device program are created before the start of work, taking into consideration the shape and size of the robot arm, the size of the workpiece, various work movements, and the work environment, so that the robot arm does not come into contact with obstacles such as people, surrounding objects, other autonomous mobile robots, etc.

To prevent the robot arm from exceeding the restricted space Sr, the position, speed, stopping state, etc. of the robot arm are monitored in real time, and if the robot arm is about to exceed the restricted space, the movement of the robot arm is forcibly stopped.

In this way, if the robot arm control device program that monitors the robot arm by providing a safeguard space Sa and restricted space Sr is independent of the programs that the robot arm performs various tasks, it is preferable because it is not affected by the programs for each task, making it more reliable.

There are no particular limitations on the control device program that monitors the robot arm. Examples of commercially available products that can be added to a robot controller include the Dual Check Safety (DCS) manufactured by FANUC Corporation, the Functional Safety Board DX200 manufactured by Yaskawa Electric Corporation, and the Safety Expansion Unit manufactured by Mitsubishi Electric Corporation. Examples of products that are pre-built into the robot controller include the RC8A controller and UNIVERSAL ROBOTS e-Series manufactured by DENSO WAVE Inc., and the robots CR-7iA, CR-4iA, CR-15iA, CR-7iA, and CR-35iA manufactured by FANUC Corporation. Among these, the CR-7iA, CR-4iA, CR-15iA, CR-7iA, CR-35iA, and CRX series robots manufactured by FANUC LTD., which are collaborative robots that comply with ISO 10218-1 (JIS B 8433-1), are particularly suitable for use.

In this embodiment, the non-contact sensors 80A, 80B, and 80C are installed as laser scanners with an upward detection direction, but additional laser scanners with a downward detection direction may be installed. This allows the downward safety protection space to be expanded.

(Warning Light)
In order to ensure the safety of workers around the robot arm, it is preferable to alert them to the existence of a work space or to intrusion into the safeguarded space by using a warning light 14 or sound. By changing the color of the light emitted by the warning light 14 according to the surrounding conditions, such as the narrowness of the gap with the surroundings or the distance of the worker to the safeguarded space, the surrounding workers can determine the condition of the robot arm 11, and it is possible to prevent the robot arm 11 from slowing down or stopping due to mistakenly approaching the dual-arm robot 10, thereby hindering productivity.

(Horizontal movement device)
The horizontal movement devices 70A, 70B, 70C are electrically or pneumatically driven to move the slider 71 to which the non-contact sensors 80A, 80B, 80C are attached, thereby changing the positions of the non-contact sensors 80A, 80B, 80C in the horizontal direction. The horizontal movement devices 70A, 70B, 70C are preferably electrically driven, which allows easy change of the stop positions of the non-contact sensors 80A, 80B, 80C, so that the stop positions can be adjusted arbitrarily depending on the working state of the robot arm 11. The horizontal movement devices 70A, 70B, 70C are preferably equipped with a control device that moves the slider 71 as follows depending on the working state of the robot arm 11.

That is, while the robot arm 11 is working at high speed, even when the vehicle body 2 is stopped or moving, it takes time to stop the work, so the safety distance becomes long. Therefore, it is preferable to move the sliders 71 of the horizontal movement devices 70A, 70B, 70C in the outward direction of the outer periphery of the vehicle body and position the non-contact type sensors 80A, 80B, 80C away from the outer periphery of the vehicle body in the outward direction. This makes it possible to obtain a sufficiently large safety distance. On the other hand, while the robot arm 11 is working at a low speed, it does not take time to stop the work, so the safety distance becomes short. Therefore, the sliders 71 of the horizontal movement devices 70A, 70B, 70C can be moved inward of the vehicle body 2 to bring the non-contact type sensors 80A, 80B, 80C closer to the vehicle body, and while the robot arm 11 is stopped, it can be brought even closer to the vehicle body and positioned near the vehicle body.

The non-contact sensors 80A, 80B, and 80C may be moved by the robot arm 11, but it is preferable to move them by the slider 71 as described above in order to eliminate the risk that the robot arm 11 or part of the end effector 20 may go outside the detection area while the non-contact sensors 80A, 80B, and 80C are moving. The moving device to which the non-contact sensors are attached may be one in which the support 76 of the moving device is rotatable, as in the mobile robot 1D with a robot arm (FIGS. 9A to 10C) of the embodiment described later.

(Robot arm)
In this embodiment, as the robot arms 11, vertical multi-joint type robot arms are provided as the left and right arms of the dual-arm robot 10. In the present invention, the robot arms are not limited to this and may be of a horizontal multi-joint type, parallel link type, etc., but by using a vertical multi-joint type, the operating range of the arm can be widened.

In addition, as shown in FIG. 1B, in the mobile robot with robot arms 1A of this embodiment, the left and right robot arms 11 are attached to bases 12, which are attached to the vehicle body 2, but the robot arms may be attached directly to the vehicle body 2 as in the mobile robot with robot arms 1B of the embodiment described below (FIGS. 6A to 7C). When attaching the robot arms 11 to the bases 12, it is preferable that the bases 12 be horizontally rotatable on the vehicle body 2. This allows various tasks to be performed in front of the robot, regardless of the orientation of the vehicle body 2 of the mobile robot with robot arms 1A, thereby optimizing tasks. It is also preferable in that the operating range of the robot arms 11 can be expanded.

The left and right robot arms 11 are mutually monitored, and it is preferable that each part of the arms, such as the arm tips, is controlled so as not to interfere with each other. Normally, the robot arms of a dual-arm robot are monitored by its robot controller. If the left and right robot arms each have an independent controller, they are monitored by a special controller that controls and monitors both controllers. This makes it possible to prevent the left and right robot arms 11 from coming into contact with each other and being damaged when an error occurs in the operation program of the robot arm 11 and the robot arm 11 is made to perform autonomous operations based on the recognition of images taken by the camera equipped in the dual-arm robot 10.

In the present invention, the robot arm is not limited to a dual-arm type. Three or more robot arms may be provided on the mobile robot with robot arms 1A, which enables a wide variety of tasks.

(End effector)
End effectors 20 are provided at the tips of the left and right robot arms 11. The end effectors 20 can be provided with a gripping section capable of gripping an object depending on the material, shape, and work to be performed on the object handled by the mobile robot with a robot arm 1A, a suction section capable of adsorbing an object, a blade for cutting strings binding cargo, and the like.

Specific examples of tasks include loading and unloading items, aligning items, assembling, tightening screws, welding, soldering, painting, etc.

Specific examples of items that the end effector can handle include boxes, sheets such as stacked cardboard, stacks of sheets bound together with string, wood, metal materials, resin materials, bottles, caps, or rolls of film, paper, or nonwoven fabric.

(Work table)
Work is carried out on the workbench 50. The workbench 50 can also be used as a platform on which to place a transport box 60 when storing the object in the transport box (FIG. 5) or removing the object from the transport box. The workbench 50 can stably hold the object. There are no particular limitations on the structure of the workbench 50 itself. Examples include a flat plate-shaped one, one with bars or walls on the left and right, front and back of the plate material to prevent the object from falling, a cage-shaped one, one made of a plate with holes, one with a convex or concave structure on the part where the object is placed to prevent the object from rattling, etc.

Depending on the work being performed, the workbench 50 may be provided with a mechanism for gripping objects, such as an electrically or pneumatically driven chuck.

(Transport box)
As described in the example of using the mobile robot with a robot arm, the mobile robot with a robot arm 1A can store an item in a transport box 60 by the robot arm 11, and can supply the item in the transport box 60 to a specific location by the robot arm 11 (FIG. 5). The transport box 60 is one that can stably hold the item. One transport box 60 may be used, or multiple transport boxes 60 may be used. The transport box 60 itself is not particularly limited. For example, the shape of the transport box 60 may be a cube, a rectangular parallelepiped, a polygonal columnar box, a cylindrical box, or the like. A transport box with or without a lid may be used. The structure of the transport box 60 is also not particularly limited, and the transport box 60 may be foldable or non-foldable. Specific examples of the transport box 60 include a cardboard box, a resin box, and a foldable container case. To prevent the item from rattling, a method may be used in which the part where the item is placed has a convex or concave structure, or a partition plate is provided.

The items being transported are not particularly limited, and examples include filled and empty containers such as bottles, jars, bags, tubes, and boxes, as well as books, food products, and machine parts, and even assortments of these items.

(Image Recognition)
In the mobile robot with a robot arm 1A of this embodiment, a camera 30 used for image recognition is provided above the base 12 of the dual-arm robot 10, that is, at a position equivalent to the head 13 if the dual-arm robot 10 were considered to be humanoid, and an image recognition system is built into the dual-arm robot 10. Image information captured by the camera 30 is sent to the control program for the robot arm via wired or wireless communication, making it possible to perform advanced operational control of the robot arm 11.

In other words, a mobile robot with a robot arm cannot generally stop precisely at a target stopping position, regardless of whether the automatic driving method is a route guidance type, an autonomous guidance type, or a tracking type. Normally, a position error of about ±50 mm occurs. Even when a correction device is used, a position error of about ±10 mm occurs. Examples of such correction devices include a sensor that reads a magnetic tape attached to the floor at the target position, and a sensor that detects targets of a particular shape installed around the target position. However, when loading or unloading cargo, if high precision is required for the positional relationship between the robot arm and the surroundings, the correction device may interfere with the transfer of cargo.

In contrast, an image recognition system uses images to recognize markers and distinctive objects around work points such as loading and unloading, and when the mobile robot with a robot arm 1A reaches the target stopping position, that information is sent to the automatic driving system. Alternatively, the image recognition system estimates the amount of deviation or angle of the actual stopping position of the mobile robot with a robot arm 1A from the target stopping position, and corrects the operation of the robot arm. This ensures that the intended operation can be performed.

In addition to using an image recognition system to correct the stopping position of the mobile robot 1A with a robot arm, the operation of the robot arm 11, such as loading and unloading, may be performed by using the image recognition system to recognize objects such as luggage, loading platforms, transport boxes, and work tables. The image recognition system may also be used to inspect the barcodes and colors of items. The image recognition system may also be used to improve safety during travel. Meanwhile, a dedicated barcode reader may be used to inspect the barcodes of items.

There are no particular limitations on the camera 30 or image recognition system used for image recognition. A known image recognition system that processes information on two-dimensional images or three-dimensional images obtained by a stereo camera or the like can be used. In addition, a system that obtains information on the size, orientation, and degree of deformation of a marker from a captured image using augmented reality (AR) and estimates the amount of deviation in the position of the robot arm based on the information may be used. The system is appropriately selected depending on the object to be recognized, the processing time, the cost, etc. In addition to conventional two-dimensional or three-dimensional image recognition systems, AI image recognition may be used. There are no particular limitations on the method of AI image recognition. Examples include a machine learning method made by OSARO Co., Ltd. and a method that enables recognition by performing a simulation of stacking items in advance for the product Alliom made by AI Cube Co., Ltd.

The installation position of the camera is not particularly limited. For example, as in the mobile robot with a robot arm 1B (FIGS. 6A to 7C) of the embodiment described later, a tall pole-shaped installation tool 31 may be erected on the mobile robot with a robot arm 1B separately from the base 12 of the robot arm 11, and the camera 30 may be installed on the installation tool 31. By setting the installation position of the camera 30 high, it is possible to check the item from a distance. Therefore, it is possible to reduce image distortion caused by the camera lens, and to prevent misidentification of the position of the item. Furthermore, since an image can be captured as long as the robot arm 11 does not block the field of view for image recognition, the image recognition calculation can be performed with plenty of time before the robot arm starts to operate. On the other hand, when an image recognition system is used for the operation of the robot arm such as loading and unloading, the camera may be installed at the tip of the robot arm. In this case, the camera can approach the luggage, making it easier to inspect the luggage, and the installation tool supporting the camera does not restrict the movement of the robot arm.

(Example of using a mobile robot with a robotic arm)
As an example of use of the mobile robot with a robot arm 1A, an example in which the mobile robot with a robot arm 1A travels through the passage A shown in Figure 4 from a waiting point P1 to an item pick point P2, works on the picked item at a work point P3 and places the item for which work has been completed, and then returns to the waiting point P1 will be described with reference to Figures 1A to 1C, Figures 2A to 2C, and Figures 3A to 3C.

As shown in Fig. 4, the mobile robot 1A with a robot arm stopped at the waiting point P1, and the mobile robot 1A with a robot arm moving from the waiting point P1 to the pick point P2, have laser scanners 80A, 80B, and 80C positioned near the vehicle body 2 on the outer periphery of the vehicle body as non-contact sensors, as shown in Figs. 1A to 1C. Each laser scanner 80A, 80B, and 80C forms vertical detection areas Da, Db, and Dc by radially scanning a vertical plane with laser light irradiated upward. These detection areas Da, Db, and Dc form a safety protection space Sa on the left and right side and back sides of the mobile robot 1A with a robot arm in a reduced state near the vehicle body. Therefore, the mobile robot 1A with a robot arm can move through narrow passages and make small turns. In particular, it can change direction without colliding with surrounding structures around corners in narrow passages.

In addition, in this embodiment, the robot arm 11 extends the end effector 20 to work on a work target in front of which there is no person, so there is no need to form a safeguard space using a non-contact sensor, and therefore no detection area is set by a non-contact sensor in front of the mobile robot with robot arm 1A. Also, since there is no practical need to consider the intrusion of obstacles into the safeguard space in the directions toward the floor and ceiling, the setting of detection areas by a non-contact sensor is omitted in these directions either.

Normally, a mobile robot checks the path while moving using a camera (image SLAM) or laser sensor (laser SLAM) equipped on the autonomous mobile robot. In the mobile robot with robot arm 1A of this embodiment, the camera 30 also faces forward so that it can check markers and distinctive objects placed around the path while moving.

At pick point P2 shown in FIG. 4, the mobile robot 1A with robot arm picks up a specified item, places it on the workbench 50, and performs a specified task. While the robot arm 11 is working, the safety protection space is set to an expanded position so as to reliably prevent people from entering the restricted space. For this reason, as shown in FIG. 2A to FIG. 2C, the slider 71 of the horizontal movement device 70A, 70B, 70C moves to the outside of the vehicle body 2, and the laser scanners 80A, 80B, 80C attached to the ends of the sliders 71 move outward from the vicinity of the vehicle body on the outer periphery of the vehicle body, and move to positions away from the right side, left side, and back of the dual-arm robot 10, and the detection direction of the laser light is scanned so that the detection area at this position forms a vertical plane parallel to the right side, left side, and back of the vehicle body 2, forming the safety protection space Sa.

The boundary of the safeguard space in front of the dual-arm robot 10 is formed by the presence of a wall, and the boundary of the safeguard space on the floor side is formed by the detection area set below the laser scanners 80A, 80B, and 80C. In addition, there is no boundary of the safeguard space above the head of the robot 10, as there is no need to consider the approach of people.

The distance to which the detection areas of the laser scanners 80A, 80B, and 80C on the left, right, and rear of the vehicle body 2 are to be placed from the restricted space Sr is appropriately selected depending on the orientation of the dual-arm robot 10, the work content, the operating speed of the robot arm 11, etc.

Therefore, on the way from pick point P2 to work point P3, the laser scanners 80A, 80B, and 80C are positioned near the vehicle body as shown in Figures 1A to 1C. Also, if at work point P3, the left side of the traveling direction of the vehicle body 2 is work area D where parts are picked, and the front side is work area E where the item picked at point P2 and the part picked at work point P3 are attached and placed, as shown in Figures 3A to 3C, the laser scanner 80A on the right side of the traveling direction of the vehicle body 2 and the laser scanner 80C on the rear side are moved to positions away from the vehicle body 2 by horizontal movement devices 70A and 70C, respectively. This ensures a sufficient safety distance on the left and rear sides of the robot arm 11, allowing the robot arm 11 to work safely.

When transporting the item that has undergone the specified operation at point P2 to point P3, the item B that has undergone the specified operation may be stored in a transport box 60 and transported, as shown in FIG. 5.

On the other hand, if the operating speed of the robot arm 11 at point P3 is slower than that during the pick operation at point P2, the required safety distance will be shorter than the safety distance during the pick operation at point P2, so the amount of movement of the laser scanners 80A, 80C toward the outside of the vehicle body 2 can also be made less than during the pick operation. The mobile robot 1A with a robot arm at point P3 in Figure 4 represents this state.

At point P3, the walls surrounding work area D on the side of the vehicle body 2 form a safeguard space, so the laser scanner 80B on the side of work area D is not used to form the safeguard space. Also, on the side of work area E on the vehicle body 2, a safeguard space is formed by the walls surrounding work area E.

After completing the work at work point P3, the horizontal movement devices 70A and 70C are moved inside the vehicle body 2 to position the laser scanners 80A, 80B, and 80C near the original outer periphery of the vehicle body, and the mobile robot with robot arm 1A is reversed and heads toward the waiting point P1 as shown by the dashed arrow. At this time, the safeguard space has been reduced, so the mobile robot with robot arm 1A can pass through narrow passages and can also make small turns around corners.

<Transformation of the Mobile Robot with Robot Arm>
The mobile robot with a robot arm of the present invention may take various forms. For example, as shown in Figures 6A to 7C, a mobile robot with a robot arm 1B may be mounted by being fixed to a vehicle body 2 as a robot arm, and the end effector 20 may have a clamping member 26 suitable for picking up and picking down bottles. This robot arm 11 may be used for placing bottles one by one on a workbench 50 at a loading point, and then lowering the bottles one by one to a predetermined position at an unloading point after a predetermined operation. Bottle alignment and other operations may also be performed while the bottles are being transported.

In addition, in this mobile robot with a robot arm 1B, the camera 30 used for image recognition is attached to a tall pole-like installation fixture 31 that stands up from the vehicle body 2, and is installed at a high position above the workbench 50. This makes it possible to reduce image distortion caused by the camera lens, and to prevent misidentification of the bottle's position.

As non-contact sensors, laser scanners 80A, 80B are attached to horizontal movement devices 70A, 70B having sliders 71 and positioned near the left and right sides of the vehicle body 2, similar to the mobile robot 1A with a robot arm shown in Figures 1A to 3C. A laser scanner 80C attached to a horizontal movement device 70C having a slider 71 is also located on the rear side of the vehicle body 2. The detection areas of these laser scanners 80A, 80B, 80C form a vertical plane, forming a safe protection space Sa.

When the robot arm 11 is performing work, depending on the work position, work speed, etc., the horizontal movement devices 70A, 70B, 70C can be used to protrude the slider 71 outside the vehicle body, as shown in Figures 7A to 7C, to horizontally move the laser scanners 80A, 80B, 80C from near the outer periphery of the vehicle body 2 to the outside.

In the mobile robot with a robot arm 1B shown in Figures 6A to 7C, an end effector 20 having a flexible gripping member suitable for picking up and down various objects may be used. The flexible gripping member is not limited to a specific one, but for example, the mobile robot with a robot arm 1C shown in Figures 8A and 8B has a multi-fingered gripping hand with a rotatable base as the flexible gripping member 27. Other examples of the flexible gripping member 27 include a gripping hand with fingers that can flexibly deform to fit the object, and a suction hand that has one suction part and a pressure part around it to stably grip the object.

The robot arm 11 of the mobile robot with a robot arm 1C shown in Figures 8A and 8B can be used for purposes such as loading various items one by one or multiple items at the same time onto a transport box 60 on a loading platform 50 at a loading point, and unloading the items one by one or multiple items at the same time to a predetermined position at an unloading point. The transport box 60 may be placed on the loading platform 50 on the vehicle body 2, or directly on the vehicle body 2.

The robot arm 11 may simply lower the transport box 60 containing the items to a predetermined location. When placing the transport box 60 on the platform 50 or lowering it to a predetermined location, the end effector 20 that picks up and drops the items may be used as is, or a different end effector suitable for handling the transport box 60 may be used.

When lowering the transport box containing the item to a predetermined position, an unloading device (not shown) separate from the robot arm 11 may be used. The unloading device may be installed on the mobile robot with the robot arm, or it may be installed at the unloading position.

The unloading device is not particularly limited, and one example is a method in which the transport box 60 is dragged down from the mobile robot with robot arm 1C using a vacuum pad or hook attached to the tip of an air cylinder, or lifted up and lowered. In this way, by using the transport box 60 and the flexible gripping member 27, the mobile robot with robot arm 1C can be ideally suited to the task of assembling small quantities of a wide variety of items into transport boxes, known as bulk picking in logistics centers.

To make it possible to move the horizontal positions of the laser scanners 80A, 80B, and 80C, a swivel-type moving device 75 may be used, as in the mobile robot with a robot arm 1D shown in Figures 9A to 10C. In this swivel-type moving device 75, one end of a support 76 serves as the center of rotation, and the laser scanners 80A, 80B, and 80C are attached to the other end. As shown in Figures 9A to 9C, when the support 76 is upright, the laser scanners 80A, 80B, and 80C are in the OFF state, and the laser scanners do not form a safety protection space.

On the other hand, when the robot arm 11 is to perform a task, as shown in Figures 10A, 10B, and 10C, the support 76 of the rotary mobile device 75 is rotated to make the support 76 horizontal, so that the detection areas of the laser scanners 80A, 80B, and 80C form a vertical plane, thereby forming a safety protection space Sa.

From the standpoint of cost, which allows for a cheap drive device, and from the standpoint of the ability to move the non-contact sensor in a short time, it is preferable to move the horizontal position of the non-contact sensor by rotation in this manner, and from the standpoint of setup work, which makes it easy to fine-tune the position of the non-contact sensor, and from the standpoint of safety, which makes it easier for people in the vicinity to predict the direction of sensor movement, it is preferable to move the non-contact sensor horizontally as described above.

In addition, the present invention can take various forms that allow the horizontal position of the non-contact sensor to be moved.

Reference Signs List 1A, 1B, 1C, 1D Mobile robot with robot arm 2 Body 10 Dual-arm robot 11 Robot arm 12 Base 13 Head 14 Warning light 20 End effector 26 Clamping member 27 Flexible gripping member 30 Camera 31 Installation tool 50 Work platform, loading platform 60 Transport box 70A, 70B, 70C Horizontal movement device 71 Slider 75 Swivel movement device 76 Support 80A, 80B, 80C Non-contact sensor, laser scanner A Passage Da, Db, Dc Detection area L Safety distance P1 Waiting point P2 Pick point P3 Working point Sa Safety protection space Sr Restricted space

Claims (4)

A mobile robot with a robot arm, the robot arm being mounted on a vehicle body and having a non-contact sensor,
The non-contact sensor has a detection area that forms a vertical plane, and the detection area forms a safety protection space for the robot arm;
The non-contact type sensor is attached to a slider that can be moved horizontally and returned to its original position on the outer periphery of the vehicle body by an electric horizontal movement device, and the horizontal movement device is equipped with a control device;
The control device for the mobile robot with a robot arm horizontally moves the non-contact sensor to a position away from the outer periphery of the vehicle body in an outward direction while the robot arm is performing high-speed work, and while the robot arm is performing low-speed work , moves the non-contact sensor closer to the vehicle body by horizontal movement on the outer periphery of the vehicle body than when the robot arm is performing high-speed work , and while the robot arm is stopped , moves the non-contact sensor even closer to the vehicle body than when the robot arm is performing low-speed work, so that the non-contact sensor is in the vicinity of the vehicle body on the outer periphery of the vehicle body. The mobile robot with a robot arm according to claim 1, wherein the non-contact sensor is a laser scanner. A method for forming a safeguard space for a mobile robot with a robot arm, the robot arm being mounted on a vehicle body, the method comprising the steps of: forming a safeguard space for the robot arm by using a non-contact sensor provided on the mobile robot with the robot arm, the method comprising the steps of:
The non-contact sensor is attached to a slider that can be moved horizontally and returned to its original position by an electric horizontal movement device, so that the detection area of the non-contact sensor is a vertical plane, and the horizontal position of the non-contact sensor can be moved by the horizontal movement device equipped with a control device, thereby making it possible to change the size of the safeguard space;
The control device positions the non-contact sensor away from the outer periphery of the vehicle body in an outward direction while the robot arm is working at high speed, positions the non-contact sensor closer to the vehicle body than when the robot arm is working at high speed while the robot arm is working at low speed, and positions the non-contact sensor even closer to the vehicle body when the robot arm is stopped than when the robot arm is working at low speed, thereby forming a safety protection space. The method for forming a safeguarded space according to claim 3, in which a laser scanner is used as the non-contact sensor.

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