JP7630978B2 - Floor Cleaning Robot - Google Patents

Description

The present invention relates to an autonomously traveling cart equipped with drive wheels and capable of self-propulsion, and a floor cleaning robot that uses the autonomously traveling cart.

Known examples of devices that are equipped with drive wheels and thus can travel autonomously include a three-wheeled vacuum cleaner with driven wheels and drive wheels (see Patent Document 1) and an automated guided vehicle with four wheels (see Patent Document 2).

However, for example, in the case of a three-wheel configuration consisting of one driven wheel and two drive wheels as in the above Patent Document 1, due to restrictions on the mounting position of the wheels, when a rotating pad for cleaning is provided in an autonomous floor cleaning robot, for example, a space-saving layout may be difficult in relation to the arrangement of the wheels, depending on the configuration of the rotating pad. Furthermore, in order to avoid the above situation, it is possible to consider, for example, a four-wheel structure as in the above Patent Document 2, in which the wheels are arranged at the four corners to ensure space for the rotating pad, but with a four-wheel structure, one of the wheels is likely to lift up due to unevenness in the running surface such as the floor, which may cause the drive wheels to slip and make it difficult to stabilize the running.

JP 2017-144055 A JP 2019-067315 A

The present invention has been made in consideration of the above points, and aims to provide an autonomous cart and a floor cleaning robot using the autonomous cart that can ensure stable ground contact performance with a simple configuration even on uneven surfaces such as floors.

The autonomous vehicle to achieve the above objective comprises two drive wheels, a drive wheel frame to which the drive wheels are fixed, two driven wheels, a driven wheel frame to which the driven wheels are fixed, and a mounting part to rotatably mount the driven wheel frame to the drive wheel frame.

Even though the autonomous vehicle has a four-wheel configuration with two drive wheels and two driven wheels, the driven wheel frame that secures the driven wheels is rotatably attached to the drive wheel frame that secures the drive wheels, so that stable ground contact performance can be ensured with a simple configuration even when the running surface is uneven, such as a floor.

In a specific aspect of the present invention, the drive wheel frame is a main frame that supports the drive source of the drive wheels together with the load, and the driven wheel frame fixes each wheel of the driven wheels at both ends of a rod-shaped member, and at least one wheel of the driven wheels touches the ground depending on the degree of unevenness of the road surface. In this case, even if the road surface is uneven, the driven wheel frame rotates relative to the main frame, making it possible for the wheels that make up the driven wheels to maintain a state of contact with the road surface.

In another aspect of the present invention, a rotation limiting mechanism is provided that limits the range of rotation of the driven wheel frame by the mounting portion. In this case, by providing an appropriate rotation limit, stable rotational operation can be maintained.

In yet another aspect of the present invention, the rotation limiting mechanism includes an elastic member that connects the driving wheel side pin provided on the driving wheel frame and the driven wheel side pin provided on the driven wheel frame while allowing them to be displaced relative to each other. In this case, a simple configuration can be used to appropriately limit rotation while allowing displacement due to rotation.

In yet another aspect of the invention, the driven wheel is rotatable relative to a horizontal plane.

The floor cleaning robot for achieving the above object is a floor cleaning robot equipped with any of the autonomously traveling carts described above, and equipped with a pad portion for cleaning floor surfaces that is attached to the bottom surface of the drive wheel frame.

The floor cleaning robot described above is equipped with an autonomous cart, which allows for a simple configuration to ensure stable ground contact performance even with uneven surfaces such as floors.

1A to 1E are conceptual diagrams for explaining the autonomous traveling vehicle according to the first embodiment. FIG. 1A is a conceptual diagram showing an example of how an autonomous traveling vehicle travels, and FIG. 1B is a diagram of a comparative example to FIG. 1A and 1B are conceptual diagrams for explaining one configuration example of a floor cleaning robot equipped with an autonomously traveling cart. FIG. 2 is a block diagram for explaining a configuration example of a floor cleaning robot. 1A to 1C are conceptual diagrams showing an autonomously traveling cart of a floor cleaning robot and its surrounding parts. FIG. 13 is a conceptual diagram showing a comparative example of a floor cleaning robot. 13A to 13D are conceptual diagrams for explaining the structure of a driven wheel frame according to a second embodiment. 4A to 4C are conceptual diagrams for explaining a rotation limiting mechanism. 11A to 11C are conceptual diagrams for explaining a rotation limiting mechanism provided in a floor cleaning robot including an autonomously traveling cart according to one modified example.

First Embodiment
An example of an autonomous traveling cart according to the first embodiment will be described below with reference to Fig. 1. Fig. 1(A) is a side view conceptually showing an autonomous traveling cart AC according to this embodiment, and Fig. 1(B) is a plan view. Figs. 1(C) to 1(E) are front views showing how the autonomous traveling cart AC travels. In each figure, directions are shown in a right-handed XYZ coordinate system, with the forward direction of the autonomous traveling cart AC being the +Z direction, the upward direction being the +Y direction, and the left and right directions being the ±X directions.

As shown in FIG. 1(A), the autonomously traveling cart AC according to this embodiment includes a traveling device 10, a traveling control unit 20, a driving wheel frame DF, a driven wheel frame TF, and an attachment unit AT. The traveling device 10 includes a first traveling unit 10A, a second traveling unit 10B, and a driven wheel unit 10C. The autonomously traveling cart AC enables autonomous traveling by driving the first and second traveling units 10A and 10B according to the control of the traveling control unit 20.

Of the traveling device 10, the first traveling unit 10A has a right wheel WR, which is one of the two driving wheels DW, and a right wheel drive unit RD, which is composed of a motor or the like for driving the right wheel WR. Similarly, the second traveling unit 10B has a left wheel WL, which is the other of the two driving wheels DW, and a left wheel drive unit LD, which is composed of a motor or the like for driving the left wheel WL. That is, the first traveling unit 10A is responsible for driving rotation of the right side of the pair of left and right rear wheels, and the second traveling unit 10B is responsible for driving rotation of the left side of the pair of left and right rear wheels. At this time, the wheel drive units RD and LD function as the driving source of the driving wheels DW. Furthermore, the first and second traveling units 10A and 10B are equipped with encoders RE and LE that measure the rotation of the wheels WR and WL. In the traveling device 10, the first traveling unit 10A and the second traveling unit 10B are driven independently, so that the autonomous traveling cart AC can move forward, backward, etc., and can also rotate (turn). In other words, the first traveling unit 10A and the second traveling unit 10B rotate the pair of left and right drive wheels DW in the same direction to enable forward and backward movement, and the pair of left and right drive wheels DW rotate in opposite directions to each other to enable rotation. In addition, by appropriately changing the direction of rotation by the traveling device 10, it may be possible to further move backward, and the direction of rotation (turn) may be rotatable in both directions. In addition, the encoders RE and LE measure the rotation of the right wheel WR and the left wheel WL, respectively, and output the measurement results to the traveling control unit 20. In addition, the right wheel WR and the left wheel WL, which are the two-wheel drive wheels DW, are fixed to the drive wheel frame DF in a rotatable state.

The driven wheel section 10C of the traveling device 10 includes a right wheel FWa and a left wheel FWb that constitute a two-wheel driven wheel TW, and the right wheel FWa and the left wheel FWb are fixed to the driven wheel frame TF in a rotatable state.

As described above, the autonomous traveling cart AC has a four-wheel configuration consisting of two drive wheels DW (WR, WL) and two driven wheels TW (FWa, FWb). In general, in a four-wheel configuration, one of the wheels is more likely to lift up than in a three-wheel configuration. In contrast, in this embodiment, this problem is solved by providing the driven wheel frame TF, etc. This will be described in more detail with reference to FIG. 2.

Returning to FIG. 1(A) and other figures, the traveling control unit 20 of the autonomous traveling cart AC is composed of, for example, various circuit boards, etc., and is connected to each part of the traveling device 10. It outputs various command signals such as drive signals to the wheel drive units RD and LD of the traveling device 10, and also obtains measurement results from the encoders RE and LE, thereby controlling the traveling of the traveling device 10 while grasping the traveling position of the autonomous traveling cart AC, etc.

As described above, the drive wheel frame DF is a support member for fixing the two-wheel drive wheel DW. In the illustrated example, the drive wheel frame DF is formed from a housing-like member and stores various parts such as the driving control unit 20 inside. The structure of the drive wheel frame DF can be various forms other than the above example. For example, it can be formed from a plate-like member with various parts placed on the plate-like member, or various parts can be attached to the lower part of the drive wheel frame DF. As described above, the drive wheel frame DF functions as a main body frame that can form the main body portion MM of the autonomously traveling cart AC, which is integrated by fixing and supporting each part of the device.

As described above, the driven wheel frame TF is a support member for fixing the two-wheel driven wheel TW. In the illustrated example, the driven wheel frame TF has a rod-shaped member as the main body, and the right wheel FWa and the left wheel FWb that constitute the two-wheel driven wheel TW are fixed at both ends of the rod-shaped member. In this case, the driven wheel frame TF functions as a member that integrates the two-wheel driven wheel TW. As a result, as shown in Figures 1(D) and 1(E), for example, the driven wheel frame TF can be tilted according to the degree (degree of height) of an obstacle (unevenness) OB on the road surface GN, which is the traveling road surface, so that at least one of the right wheel FWa and the left wheel FWb that constitute the driven wheel TW can be in contact with the ground.

The attachment part AT is a member for rotatably attaching the driven wheel frame TF to the driving wheel frame DF. In the illustrated example, the driven wheel frame TF and the driving wheel frame DF are connected by a cylindrical member CC extending in the traveling direction, i.e., the Z direction, and as shown in Fig. 1(C) to Fig. 1(E), the driven wheel frame TF is in a state in which it can rotate around the cylindrical member CC. As a result, even if there is an obstacle (unevenness) OB on the road surface GN on which the autonomous traveling cart AC is traveling, the autonomous traveling cart AC can overcome the obstacle OB by rotating the driven wheel frame TF together with the two-wheeled driven wheel TW associated with it. In addition, the driven wheel frame TF and the two-wheeled driven wheel TW that rotate together around the axis of the cylindrical member CC as described above are the movable part MA with respect to the main body part MM. In other words, the attachment part AT is a member that rotatably attaches the movable part MA to the main body part MM. In addition, in the above case, the main body part MM side including the drive wheel frame DF is relatively heavier in weight, and the movable part MA side including the driven wheel frame TF is relatively lighter, making it easier for the movable part MA to rotate relative to the main body part MM.

As described above, the movable part MA rotates relative to the main body part MM, i.e., the movable part MA side is capable of changing its position relative to the main body part MM. Therefore, even if the movable part MA tilts, as shown in FIG. 1(D) and FIG. 1(E), the main body part MM does not necessarily tilt with the movable part MA, and both the right wheel WR and the left wheel WL constituting the drive wheel DW on the main body part MM side can be maintained in a state in which they are placed on the road surface GN. On the other hand, on the movable part MA side, the driven wheel frame TF rotates, so that at least one of the right wheel FWa and the left wheel FWb constituting the driven wheel TW is maintained in a state in which it is in contact with the ground. In other words, the autonomously traveling cart AC can travel stably by maintaining a state in which the two points of the right wheel WR and the left wheel WL and at least one point on the movable part MA side are in contact with the ground.

In order to facilitate the above rotational movement, it is conceivable that the movable part MA, for example, has a certain degree of flexibility in the driven wheel frame TF, that the driven wheels TW have elasticity (contraction and expansion), or that suspensions or the like are provided. The same can be considered for the drive wheel frame DF and drive wheels DW on the main body part MM side.

The operation of the autonomous traveling cart AC during traveling will be described below with reference to FIG. 2. FIG. 2(A) is a conceptual diagram showing an example of how the autonomous traveling cart AC travels, and FIG. 2(B) is a diagram of a comparative example to FIG. 2(A). Note that the autonomous traveling cart ACx of the comparative example shown in FIG. 2(B) differs from the present embodiment illustrated in FIG. 2(A) in that all of the wheels in the total four-wheel configuration consisting of two driving wheels DW (WR, WL) and two driven wheels TW (FWa, FWb) are attached to one large frame FR.

In the above case, first, in the autonomous traveling cart AC according to this embodiment, as shown in FIG. 2(A) and as described with reference to FIG. 1(E) etc., if an obstacle OB is present on the right side of the autonomous traveling cart AC in the forward direction (+Z direction) of the autonomous traveling cart AC, when the autonomous traveling cart AC reaches the location of the obstacle OB, first, the right wheel FWa of the two-wheeled driven wheel TW runs over the obstacle OB, and as the autonomous traveling cart further advances, the movable part MA rotates relative to the main body part MM, causing the movable part MA to tilt and enabling the autonomous traveling cart AC to overcome the obstacle OB. At this time, the main body part MM side remains horizontal without tilting, that is, both the right wheel WR and the left wheel WL are maintained on the road surface GN, until the drive wheel DW reaches the obstacle OB.

In contrast, in the case of the autonomous traveling cart ACx shown in FIG. 2(B) as a comparative example, if an obstacle OB is present in a similar position, as shown, the right wheel FWa runs over the obstacle OB and the entire autonomous traveling cart ACx, including the frame FR, tilts at the same time. As a result, the right wheel WR, i.e. the drive wheel DW, which is on the same side as the right wheel FWa, also tilts, and as shown, there is a high possibility that the right wheel WR will lift off the road surface GN. Note that the same thing can also happen to the left side, i.e. the left wheel WL which constitutes the drive wheel DW, if there is an obstacle OB.

As described above, if the wheels WR, WL that make up the drive wheels DW are lifted and spinning freely, for example, the drive wheels DW may slip, making it impossible to stabilize the vehicle's running, or errors may occur in determining the running position of the autonomously running cart AC based on the measurement results from the encoders RE, LE. In contrast, this embodiment uses the above-mentioned configuration to avoid or suppress such situations.

As described above, the autonomously traveling cart AC according to this embodiment includes a two-wheel drive wheel DW, a drive wheel frame DF to which the drive wheel DW is fixed, a two-wheel driven wheel TW, a driven wheel frame TF to which the driven wheel TW is fixed, and a mounting part AT to which the driven wheel frame TF is rotatably mounted to the drive wheel frame DF. Even in the autonomously traveling cart AC having a total of four wheels, with the two-wheel drive wheel DW and the two-wheel driven wheel TW as described above, the driven wheel frame TF to which the driven wheel TW is fixed is rotatably mounted to the drive wheel frame DF to which the drive wheel DW is fixed, thereby ensuring stable ground contact performance against unevenness of the traveling surface such as the floor surface (road surface GN) as an obstacle OB with a simple configuration.

Below, an example of the floor cleaning robot 100 equipped with the autonomously traveling cart AC according to this embodiment will be described with reference to FIG. 3 and other figures. FIG. 3(A) is a conceptual side view for explaining an example of the configuration of the floor cleaning robot 100 equipped with the autonomously traveling cart AC, and FIG. 3(B) is a bottom view. Also, FIG. 4 is a block diagram for explaining an example of the configuration of the floor cleaning robot 100. Furthermore, FIG. 5(A) to FIG. 5(C) are conceptual diagrams showing the autonomously traveling cart AC of the floor cleaning robot 100 and its surrounding parts, with FIG. 5(A) being a side view, FIG. 5(B) being a bottom view, and FIG. 5(C) being a front view.

For example, as shown in FIG. 3(A) and FIG. 3(B), the floor cleaning robot 100 according to this embodiment includes, in addition to the parts constituting the autonomously traveling cart AC, a cleaning pad 50 for cleaning and a cleaning pad drive control unit PD. In addition, although not shown, a distance measuring device for grasping the surrounding situation, a water tank, a water sprinkling device, and even a drainage recovery device may be provided to enable cleaning while sprinkling water. Furthermore, it is possible to have a device for handling map information, store the travel route in advance, and set the cleaning route in advance. Each of these devices can be stored in the housing CS of the floor cleaning robot 100. In the illustrated example, the housing CS is placed on the drive wheel frame DF, which is the main body frame. From another perspective, the drive wheel frame DF supports the wheel drive units RD and LD, which are the drive sources of the drive wheels arranged on the lower side, together with the objects stored in the housing CS, thereby functioning as the main body frame of the autonomously traveling cart AC and the floor cleaning robot 100.

In order to enable traveling in cooperation with each of the above-mentioned parts, the traveling control unit 20 in the floor cleaning robot 100 cooperates with each part of the traveling device 10, as well as with, for example, the cleaning pad drive control unit PD. These will be described later with reference to the block diagram shown in FIG. 4. In addition, in the example shown in FIG. 3(A), the control unit CR is a combination of various circuits including the traveling control unit 20. In other words, the control unit CR is composed of, for example, one or more various circuit boards, and controls various operations in the floor cleaning robot 100.

Below, we will explain the cleaning pad 50 and cleaning pad drive control unit PD, which are the main components of the floor cleaning robot 100 and are used for cleaning floors.

The cleaning pad 50 is a disk-shaped member attached to the underside of the drive wheel frame DF, which is the main frame of the autonomous traveling cart AC, and comes into contact with the floor surface to be cleaned, i.e., the road surface GN. It is a pad portion for cleaning the floor surface that rotates while in contact with the road surface (floor surface) GN during cleaning. In this example, the cleaning pad 50 rotates in one direction around the axis portion XA of the cleaning pad 50, as shown by the arrow A1 in FIG. 3(B), for example, to polish the road surface (floor surface) GN.

The cleaning pad drive controller PD is composed of, for example, various circuit boards, and is connected to the travel controller 20 and also to the cleaning pad 50. The cleaning pad drive controller PD controls the drive of the cleaning pad 50 according to the travel situation in accordance with the command signal from the travel controller 20.

Below, an example of the configuration of the floor cleaning robot 100 described above will be described with reference to the block diagram shown in FIG. 4. In particular, the parts of the floor cleaning robot 100 related to the driving control operation in the control unit CR will be described. In the illustrated example, the main control unit MP, which is the main body part of the control unit CR and is composed of a CPU or the like and is responsible for overall operation control of each part of the floor cleaning robot 100, is provided as the main part of the driving control unit 20. In other words, in this example, the driving control unit 20 is directly or indirectly connected to each part of the floor cleaning robot 100, and performs driving control while also performing various overall operation processing for floor cleaning.

In order to achieve the above aspect, in the illustrated example, the traveling control unit 20 includes a main control unit MP composed of a CPU or the like, as well as a drive adjustment unit DA for adjusting the drive of the traveling device 10.

The main control unit MP is connected to each component of the traveling device 10 and is also connected to the cleaning pad drive control unit PD, and performs driving control of the cleaning pad according to the traveling condition as well as driving control. The main control unit MP also includes a traveling position confirmation unit DC that confirms the measurement results. The traveling position confirmation unit DC confirms the traveling position based on the measurement results of the left and right encoders RE, LE provided corresponding to the left and right wheels WR, WL (drive wheels DW).

The main control unit MP controls the drive of each wheel drive unit RD, LD via the drive adjustment unit DA to control the traveling of the traveling device 10. At this time, the traveling device 10 adjusts the drive state (rotation speed, i.e., traveling speed, etc.) of each wheel WR, WL that constitutes the driving wheel DW based on the result of the position confirmation by the traveling position confirmation unit DC. In addition, in conjunction with this, it also adjusts the drive state of the cleaning pad 50 (pad rotation speed, etc.).

As described above, each part of the floor cleaning robot 100 works together to detect its own position while cleaning the floor.

The following describes the autonomous traveling cart AC and its surrounding structure of the floor cleaning robot 100 with reference to FIG. 5(A) and other figures. In FIG. 5(A) to FIG. 5(C), only the drive wheel frame DF, the driven wheel frame TF, the mounting part AT connecting them, the traveling device 10, and the structure on the underside of the drive wheel frame DF are shown. In the illustrated example, the drive wheel frame DF is a plate-shaped member, and the various parts stored in the housing CS (see FIG. 3, etc.) are placed on the drive wheel frame DF as objects to be placed on it. Meanwhile, the lower part of the drive wheel frame DF is provided with, for example, the various parts constituting the traveling device 10, as well as a cleaning pad 50 for cleaning. In other words, the cleaning pad 50 is a pad part for cleaning the floor surface that is attached to the bottom surface of the drive wheel frame DF.

In the illustrated example, the mounting part AT connects the first connection part CN1 as a convex part provided on the driving wheel frame DF to the second connection part CN2 as a concave part provided in the driven wheel frame TF with a cylindrical pin PN, and the driven wheel frame TF can rotate around the pin PN extending in the Z direction. In the illustrated example, the pair of left and right driven wheels FWa, FWb are attached and fixed to the bottom surface of the driven wheel frame TF and have a caster-like structure, and can rotate on a horizontal plane.

Here, in the case where the cleaning pad 50 is attached to the bottom side of the autonomously traveling cart AC of the floor cleaning robot 100, more specifically, to the underside of the drive wheel frame DF, as in this embodiment, as is particularly clear from FIG. 5B, the positional relationship between the cleaning pad 50 and each wheel WR, WL, FWa, FWb on the underside or bottom surface part is important in determining the size of the entire device and the size of the cleaning pad 50. In this embodiment, since there are a total of four wheels, as shown in the figure, the four wheels WR, WL, FWa, FWb can be arranged at the four corners of the rectangular bottom surface part defined by the underside of the drive wheel frame DF and the driven wheel frame TF, so that the circular cleaning pad 50 can be arranged over as large an area as possible relative to the entire device.

In contrast, for example, as shown in the side view and bottom view of Comparative Example α1 in FIG. 6, a three-wheel configuration with two driving wheels WR and WL and one driven wheel FW has the advantage that the wheels are less likely to float compared to a four-wheel configuration, but the diameter R1 of the cleaning surface is smaller than the body width W1 and body length H1. This is because the driven wheel FW cannot be placed at one of the four corners from the perspective of stabilization. For this reason, if you want to increase the diameter R1 of the cleaning surface, you need to increase the body length H1 from the state shown in Comparative Example α1, for example, as shown in the side view and bottom view of Comparative Example α2 in FIG. 6. In other words, in the case of a three-wheel configuration, it may be difficult to achieve a space-saving layout in relation to the placement of the wheels WR, WL, and FW. In contrast, as shown in the side view and bottom view of Comparative Example α3 in Figure 6, by using a four-wheel configuration with two drive wheels WR, WL and two driven wheels FWa, FWb, it is possible to increase the diameter R1 of the cleaning surface while keeping the main body length H1 compact without increasing it. However, in a configuration in which four wheels WR, WL, FWa, FWb are provided on one frame FR as in Comparative Example α3, there is a possibility that the wheels WR, WL, FWa, FWb, especially the drive wheels WR, WL, may float, as explained with reference to Figure 2 (B), for example.

In contrast, in this embodiment, the floor cleaning robot 100 is configured using an autonomously traveling cart AC. This allows for stable travel while using a large circular cleaning pad 50. From another perspective, this can also be said to make it possible to miniaturize the entire device relative to the cleaning pad 50.

In addition, to the extent that interference with the wheels WR, WL, FWa, and FWb can be avoided, the cleaning pad 50 can be made large enough to fit just to the edge of the rectangular bottom surface or to extend partially beyond it, making it possible to clean every corner of the floor surface.

As described above, the floor cleaning robot 100 according to this embodiment is equipped with an autonomously traveling cart AC, and a cleaning pad 50 which is a pad portion for cleaning floor surfaces that is attached to the bottom surface of the drive wheel frame DF. In this case, by being equipped with an autonomously traveling cart AC, the floor cleaning robot 100 can ensure stable ground contact performance against unevenness of the road surface GN, which is the traveling surface such as a floor surface, with a simple configuration.

Second Embodiment
Hereinafter, an example of an autonomous traveling cart and a floor cleaning robot equipped with the same according to the second embodiment will be described with reference to Fig. 7 and the like. The autonomous traveling cart AC and the floor cleaning robot 100 equipped with the same according to this embodiment are different from those of the first embodiment in that a rotation limiting mechanism RL for limiting the rotation range of the driven wheel frame TF by the mounting part AT is provided. However, other points are the same as those of the first embodiment, so illustrations and descriptions of the autonomous traveling cart AC and the floor cleaning robot 100 will be omitted. In this embodiment, the rotation limiting mechanism RL, which is different from the first embodiment, is related to the autonomous traveling cart AC of the floor cleaning robot 100, so this is not only an embodiment of the floor cleaning robot 100 but also an embodiment of the autonomous traveling cart AC.

Figure 7(A) is a conceptual front view for explaining the structure of the driven wheel frame TF of the autonomous traveling cart AC having a rotation limiting mechanism RL, and Figure 7(B) is a front view showing an example of the driven wheel frame TF in a tilted state when climbing over an obstacle OB. Also, Figures 7(C) and 7(D) are partial enlarged views of Figures 7(A) and 7(B). Furthermore, Figure 8(A) is a conceptual plan view showing the rotation limiting mechanism RL, and Figures 8(B) and 8(C) are further partial enlarged views of the rotation limiting mechanism RL in Figures 7(C) and 7(D). Note that in Figures 8(B) and 8(C), the horizontal reference line HS is shown by a dashed line to show the state of tilt by comparison.

First, as shown in FIG. 7(A) and other figures, in this embodiment, a pair of rotation limiting mechanisms RL are provided on both ends of the rod-shaped driven wheel frame TF, symmetrically on the left and right sides of the pin PN that constitutes the mounting portion AT. For example, as shown in FIG. 7(B), when the driven wheel frame TF is tilted by an obstacle (unevenness) OB, the rotation limiting mechanism RL functions as a stopper to allow the driven wheel frame TF to tilt to a certain extent, but not to tilt beyond that. In other words, as shown in FIG. 7(C) and FIG. 8(B), when the driven wheel frame TF is not tilted, movement is permitted. On the other hand, as shown in FIG. 7(D) and FIG. 8(C), when the driven wheel frame TF is tilted to a certain extent, further tilting is restricted. In addition, in order to maintain the posture shown in FIG. 7(A), FIG. 7(B), or FIG. 8(B) when traveling on a horizontal plane, the mounting part AT may be provided with a neutral position maintaining mechanism, for example, a spring mechanism, to hold the mounting part AT at the top and bottom.

Below, an example of the configuration of the rotation limiting mechanism RL for performing the above-mentioned function will be described mainly with reference to FIG. 8(A). As shown in FIG. 8(A) and other figures, the rotation limiting mechanism RL has a driving wheel side pin DP provided on the driving wheel frame DF, a driven wheel side pin TP provided on the driven wheel frame TF, and a ring-shaped elastic member (rubber band) EP that connects them. In other words, the elastic member EP connects the driving wheel side pin DP and the driven wheel side pin TP while allowing them to be displaced relative to each other. As shown in FIG. 8(B) and FIG. 8(C), the driven wheel frame TF has an insertion hole HL for inserting the driving wheel side pin DP extending from the driving wheel frame DF.

First, when the driven wheel frame TF is not tilted as shown in FIG. 8(B) or FIG. 7(C), the driving wheel side pin DP and the driven wheel side pin TP are close to each other, so the elastic member EP does not apply a large force to them, and the driven wheel frame TF is in a rotatable state. In contrast, when the driven wheel frame TF is tilted to a certain extent as shown in FIG. 8(C) or FIG. 7(D), the driving wheel side pin DP and the driven wheel side pin TP are farther apart, so the elastic member EP exerts a force that tries to bring them closer together. In other words, the rotation of the driven wheel frame TF is restricted. As described above, in the rotation restriction mechanism RL with a simple configuration, by appropriately determining the strength of the elastic member EP and the relative position of the driving wheel side pin DP and the driven wheel side pin TP, it is possible to appropriately restrict rotation while allowing displacement due to the rotation of the driving wheel frame DF.

The rotation limiting mechanism RL is not limited to the above example, and various modified examples can be applied. For example, as shown in one modified example in Figures 9(A) to 9(C) corresponding to Figures 8(A) to 8(C), it is possible to have a configuration in which there is no elastic member EP or driven wheel side pin TP, but instead a driving wheel side pin DP and an insertion hole HL for inserting it are provided, and the driving wheel side pin DP hits the side of the insertion hole HL to limit rotation.

〔others〕
The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the present invention.

First, of the above, the attachment part AT is not limited to the above, and may be in other forms as long as the necessary rotational movement is obtained. In the above form, it is considered to be an effective form to provide only accurate rotational movement without providing play or the like with respect to the cylindrical shaft.

In the above, the travel position is calculated using the encoders RE and LE, but this is not limiting, and for example, various sensors may be installed and position measurements may be performed in combination with these. For example, in the case of the floor cleaning robot 100, if the action of the rotation of the cleaning pad 50 affects position fluctuations, the position may be grasped taking this into account.

In the above, the autonomously traveling cart AC shown in, for example, FIG. 1 is configured to rotate independently on the left and right sides, but it is also possible to configure it so that they are driven integrally.

Furthermore, various configurations of the floor cleaning robot 100 are possible, and for example, the present application can be applied to a dry floor cleaning robot that does not have a water tank or the like, in order to make it smaller and thinner.

In addition, the above describes the case where the autonomously traveling cart AC is applied to a floor cleaning robot (cleaning robot) 100 that moves while measuring its traveling position, but it is also conceivable that the present application can be applied to various moving bodies (mobile robots, transport robots) that require precise movement similar to the floor cleaning robot 100.

10...running device, 10A...first running part, 10B...second running part, 10C...driven wheel part, 20...running control part, 50...cleaning pad, 100...floor cleaning robot (cleaning robot), A1...arrow, AC...autonomous running cart, ACx...autonomous running cart, AT...mounting part, CC...cylindrical member, CN1...first connection part, CN2...second connection part, CR...control part, CS...housing, DA...drive adjustment part, DC...running position confirmation part, DF...drive wheel frame (main body frame), DP...drive wheel side pin, DW...drive wheel, EP...elastic member (rubber band), FR...frame, FW ...Driven wheel, FWa...Right wheel (Driven wheel), FWb...Left wheel (Driven wheel), GN...Road surface (floor surface), H1...Main body length, HL...Through hole, LD...Left wheel drive unit, MA...Moving part, MM...Main body part, MP...Main control unit, OB...Obstacle (unevenness), PD...Cleaning pad drive control unit, PN...Pin, R1...Diameter, RD...Right wheel drive unit, RE, LE...Encoder, RL...Rotation limiting mechanism, TF...Driven wheel frame, TP...Driven wheel side pin, TW...Driven wheel, W1...Main body width, WL...Left wheel (Driven wheel), WR...Right wheel (Driven wheel), XA...Axle part, α1 to α3...Comparative example

Claims (5)

A two-wheel drive wheel configuration;
A drive wheel frame for fixing the drive wheel;
A two-wheel driven wheel;
A driven wheel frame for fixing the driven wheel;
a mounting portion extending in a traveling direction and configured to rotatably mount the driven wheel frame to the driving wheel frame;
a rotation limiting mechanism that limits a rotation range of the driven wheel frame by the mounting portion;
A floor cleaning robot comprising: a pad portion for cleaning floor surfaces attached to the bottom surface of the driving wheel frame so as to protrude partially toward the bottom surface of the driven wheel frame, and having a width greater than the distance between the two wheels that constitute the driving wheels . The drive wheel frame is a main body frame that supports a drive source of the drive wheel together with a load,
2. The floor cleaning robot according to claim 1, wherein the driven wheel frame fixes the wheels of the driven wheels at both ends of a rod-shaped member, and at least one of the driven wheels comes into contact with the ground depending on the degree of unevenness of a road surface on which the robot is traveling. 3. The floor cleaning robot according to claim 1, wherein the rotation limiting mechanism includes an elastic member that connects a driving wheel side pin provided on the driving wheel frame and a driven wheel side pin provided on the driven wheel frame while allowing them to be displaced relative to each other. The floor cleaning robot according to claim 1 , wherein the driven wheel is rotatable with respect to a horizontal plane. The floor cleaning robot according to claim 1, wherein the pad portion for cleaning the floor surface is a circular member that has a rotation axis at the center of the bottom surface of the drive wheel frame and rotates in a plane along the bottom surface.

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