Mobile robot

Abstract

To inhibit the arm part of a mobile robot from touching an object in a periphery thereof while inhibiting the mobile robot from falling down during turning travel.SOLUTION: A mobile robot comprises: a carriage part; a movement mechanism for allowing the carriage part to carry out turning travel; an arm part including a first joint connected to the carriage part, a carriage-side arm adjustment part connected to the first joint, an intermediate arm adjustment part connected to the carriage-side arm adjustment part, and a tip-side arm region connected to the intermediate arm adjustment part; and a control unit. The carriage-side arm adjustment part includes one joint including one orthogonal rotation axis orthogonal to a first rotation axis, or a plurality of joints including a plurality of orthogonal rotation axes orthogonal to the first rotation axis and parallel to each other. During turning travel of the carriage part, the control unit controls the first joint such that a center-of-gravity position of the arm part moves in a direction of being closer to a turning center than the center-of-gravity position before a start of turning, and controls the intermediate arm adjustment part such that the tip-side arm region moves in a direction having a component in a direction opposite to a direction of movement of the tip-side arm region resulting from rotation of the first joint.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to mobile robots. [Background technology]

[0002] Non-Patent Document 1 describes the stability of a vehicle-mounted manipulator, in which the manipulator is mounted on a vehicle, to prevent the manipulator from tipping over during operation. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] "Stabilization Control of a Vehicle-Mounted Manipulator" Transactions of the Society of Instrument and Control Engineers, Vol. 31, No. 7, 861 / 870 (1995) Summary of the Invention [Problem to be solved by the invention]

[0004] A mobile robot including a cart and an arm mounted on the cart can be used to grasp and manipulate an object and transport the object. One of the preferred basic structures of the arm includes a first joint connected to the cart and having a first rotation axis in a vertical direction, a cart-side arm adjustment unit having a lower end connected to the first joint, and an upper limb extending from an upper end of the cart-side arm adjustment unit to an end effector. The cart-side arm adjustment unit includes one joint having an orthogonal rotation axis perpendicular to the first rotation axis, or multiple joints each having multiple orthogonal rotation axes perpendicular to the first rotation axis and parallel to each other. When manipulating an object, the mobile robot takes a posture in which the upper limb is extended in a horizontal direction perpendicular to the orthogonal rotation axis of the cart-side arm adjustment unit. The direction in the horizontal plane in which the upper limb is extended can be changed by rotating the first rotation axis. When running, the mobile robot takes a posture in which the upper limb is extended in a direction generally parallel to the traveling direction. At this time, the orthogonal rotation axis of the carriage-side arm adjustment unit is in a horizontal direction that is approximately perpendicular to the traveling direction.

[0005] It is necessary to prevent a mobile robot from tipping over due to the inertial force generated when accelerating, decelerating, or turning. Tipping over due to the inertial force generated when accelerating or decelerating can be prevented by rotating a joint having an orthogonal rotation axis in the cart-side arm adjustment unit to tilt the arm forward or backward. In order to prevent tipping over due to the inertial force generated when turning, it is necessary to move the center of gravity of the arm toward the center of rotation, which is to the right or left of the traveling direction. If the arm has a rotation axis parallel to the traveling direction at a position close to the cart, the necessary center of gravity can be moved by tilting the arm above the rotation axis to the right or left of the traveling direction. However, the arm having the basic structure assumed here does not have a rotation axis parallel to the traveling direction in the cart-side arm adjustment unit, so that almost the entire arm cannot be tilted to the right or left of the traveling direction.

[0006] The present disclosure aims to prevent a mobile robot from tipping over during turning, the mobile robot having a structure including a cart section and an arm section mounted on the cart section, the arm section including a first joint connected to the cart section and having a first rotation axis in a vertical direction, a cart-side arm adjustment section having a lower end connected to the first joint, and an upper limb section extending from an upper end of the cart-side arm adjustment section to an end effector, the cart-side arm adjustment section including one joint having an orthogonal rotation axis perpendicular to the first rotation axis, or multiple joints each having multiple orthogonal rotation axes perpendicular to the first rotation axis and parallel to each other, and further aims to prevent movement of the tip of the arm section when the arm section operates to prevent tipping over during turning. [Means for solving the problem]

[0007] One aspect of the present disclosure provides an arm unit including: a carriage unit; a moving mechanism for rotating the carriage unit; a first joint connected to the carriage unit and having a first rotation axis in a vertical direction; a carriage-side arm adjustment unit having a first end and a second end, the first end being connected to the first joint; an intermediate arm adjustment unit having a third end and a fourth end, the third end being connected to the second end; and a tip-side arm region connected to the fourth end; and a control unit for controlling the moving mechanism and the arm unit, wherein the carriage-side arm adjustment unit is configured to rotate in an orthogonal direction perpendicular to the first rotation axis. the control unit controls the first joint so that, when the cart unit turns, the center of gravity position of the arm unit moves in a direction closer to a center of rotation than the center of gravity position before the turn starts, and controls the intermediate arm adjustment unit so that the tip-side arm region moves in a direction that has a component in the opposite direction to the direction of movement of the tip-side arm region due to rotation of the first joint, compared to when the intermediate arm adjustment unit is not operated. Effect of the Invention

[0008] According to the present disclosure, a mobile robot including a cart and an arm mounted on the cart, the arm including a first joint connected to the cart and having a first rotation axis in a vertical direction, a cart-side arm adjustment unit having a lower end connected to the first joint, and an upper limb extending from an upper end of the cart-side arm adjustment unit to an end effector, the cart-side arm adjustment unit including one joint having an orthogonal rotation axis perpendicular to the first rotation axis, or multiple joints each having multiple orthogonal rotation axes perpendicular to the first rotation axis and parallel to each other, can be prevented from tipping over during a turn. Furthermore, when the arm unit operates to prevent tipping over during a turn, the movement of the tip of the arm unit can be suppressed. This reduces the risk that the tip of the arm unit will come into contact with a surrounding object during a turn. Furthermore, when an object is held at the tip of the arm unit, the acceleration of the held object can be suppressed in association with the operation of the arm unit to prevent tipping over during a turn. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a mobile robot according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing the control unit of the mobile robot according to the embodiment. [Figure 3A] FIG. 3A is an explanatory diagram showing the operation of a joint of the mobile robot according to the embodiment. [Figure 3B] FIG. 3B is an explanatory diagram showing the operation of a joint of the mobile robot according to the embodiment. [Figure 3C] FIG. 3C is an explanatory diagram showing the operation of a joint of the mobile robot according to the embodiment. [Figure 3D] FIG. 3D is an explanatory diagram showing the notation of joints and links according to the JIS standard. [Figure 4] FIG. 4 is a side view showing a representative posture of the mobile robot according to the embodiment. [Diagram 5] FIG. 5 is a plan view showing a representative posture of the mobile robot according to the embodiment. [Figure 6] FIG. 6 is a rear view showing the zero moment point in a representative posture of the mobile robot according to the embodiment. [Figure 7] FIG. 7 is a plan view showing the turning motion of the mobile robot according to the embodiment. [Figure 8A] FIG. 8A is a graph showing a change over time in a rotation angle of a first joint when the mobile robot of the embodiment is turning. [Figure 8B] FIG. 8B is a graph showing a change over time in the rotation angle of the second joint when the mobile robot in the embodiment turns while running. [Figure 8C] FIG. 8C is a graph showing a change over time in the rotation angle of the third joint when the mobile robot in the embodiment turns. [Figure 8D] FIG. 8D is a graph showing a change over time in the rotation angle of the fourth joint when the mobile robot of the embodiment turns. [Figure 8E] FIG. 8E is a graph showing a change over time in the rotation angle of the fifth joint when the mobile robot of the embodiment turns while running. [Figure 8F] FIG. 8F is a graph showing a change over time in the rotation angle of the sixth joint when the mobile robot of the embodiment turns while running. [Figure 8G] FIG. 8G is a graph showing a change over time in the rotation angle of the seventh joint when the mobile robot of the embodiment is turning. [Figure 8H] FIG. 8H is a graph showing a change over time in the rotation angle of the eighth joint when the mobile robot in the embodiment is turning. [Figure 9] FIG. 9 is a plan view showing the operation of the mobile robot according to the embodiment when turning. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an example of an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, the same or substantially equivalent elements, members, and parts are given the same reference numerals. In addition, the dimensions and ratios of the drawings are exaggerated for the convenience of explanation and may differ from the actual ratios.

[0011] 1, a mobile robot 26 according to an embodiment of the present invention includes a cart unit 22 and an arm unit 28. The arm unit 28 is, for example, a robot having eight degrees of freedom.

[0012] In the example shown in Fig. 1, the cart section 22 is substantially rectangular parallelepiped shaped. In the following, an X-axis, a Y-axis, and a Z-axis are set as a coordinate system of the cart section 22. The X-axis direction is the front-rear direction of the cart section 22, the Y-axis is the left-right direction of the cart section 22, and the Z-axis is the height direction of the cart section 22. This left-right direction is also the width direction of the cart section 22. In the following, an example will be described in which the height direction of the cart section 22 coincides with the vertical direction.

[0013] The carriage unit 22 is provided with a moving mechanism 24 and a control unit 70. The control unit 70 controls the operation of the moving mechanism 24 and the arm unit 28. The moving mechanism 24 has two driving wheels 24A, two driven wheels 24B, and two rotational drive sources (motors) (not shown) that independently drive the two driving wheels 24A. The two driving wheels 24A are provided on the carriage unit 22 spaced apart in the left-right direction, and the two driven wheels 24B are also provided on the carriage unit 22 spaced apart in the left-right direction. The driving wheels 24A are provided relatively to the rear of the vehicle, and the driven wheels 24B are provided relatively to the front of the vehicle. The driving wheels 24A and the driven wheels 24B support the mobile robot 26. The driving wheels 24A and the driven wheels 24B may be collectively referred to as wheels.

[0014] 4 and 6, the driving wheels 24A and the driven wheels 24B are in contact with the floor surface LF, thereby supporting the mobile robot 26. The square connecting the four points of the driving wheels 24A and the driven wheels 24B is the support area SA.

[0015] The driving wheels 24A are rotationally driven by a rotary drive source (not shown). For example, the two driving wheels 24A can be rotated at a constant rotation speed to cause the cart section 22 to move linearly. Also, the two driving wheels 24A can be rotated at different rotation speeds (differentially) to cause the left and right wheels 24A to turn. In contrast, the driven wheels 24B are not rotationally driven by a drive source and can rotate freely. Furthermore, the rotation axis of the driven wheels 24B can freely change direction within a horizontal plane. In other words, the driven wheels 24B are swivel casters (swivel casters).

[0016] The arm portion 28 has eight joints (a first joint 31, a second joint 32, a third joint 33, a fourth joint 34, a fifth joint 35, a sixth joint 36, a seventh joint 37 and an eighth joint 38), three links (a first link 41, a second link 42 and a third link 43), and a hand 50.

[0017] The first joint 31 has a first rotation axis J1 in a specific direction relative to the cart unit 22. In this embodiment, the specific direction is a normal direction to the top surface 22A of the cart unit 22. In the illustrated example, the top surface 22A of the cart unit 22 is parallel to the floor surface LF of the mobile robot 26. Therefore, the normal direction to the top surface 22A of the cart unit 22 is also the normal direction to the floor surface LF. When the floor surface LF is horizontal, the direction of the first rotation axis J1 is vertical.

[0018] The second joint 32 is connected to the first joint 31 without any other joint therebetween. The second joint 32 has a second rotation axis J2 that is perpendicular to the first rotation axis J1.

[0019] One end 41A of the first link 41 is connected to the second joint 32. The first link 41 has a length from the one end 41A in a direction perpendicular to the second rotation axis J2.

[0020] The third joint 33 is provided at the other end 41B of the first link 41. The third joint 33 has a third rotation axis J3 that is parallel to the second rotation axis J2.

[0021] One end 42A of the second link 42 is connected to the third joint 33. The second link 42 has a length from the one end 42A in a direction perpendicular to the third rotation axis J3.

[0022] The fourth joint 34 is connected to the other end 42B of the second link 42. The fourth joint 34 has a fourth rotation axis J4 that is parallel to the third rotation axis J3.

[0023] As shown in FIG. 4, in the arm section 28, the bogie side arm adjustment section 28A is a section including the second joint 32, the first link 41, the third joint 33, the second link 42, and the fourth joint 34. The second joint 32 is a first end section 28A1 of the bogie side arm adjustment section 28A, and is connected to the first joint 31. The fourth joint 34 is a second end section 28A2 of the bogie side arm adjustment section 28A. The second rotation axis J2, the third rotation axis J3, and the fourth rotation axis J4 are orthogonal to the first rotation axis J1 when viewed in the Z-axis direction, and are examples of orthogonal rotation axes. The number of joints having orthogonal rotation axes orthogonal to the first rotation axis J1 included in the bogie side arm adjustment section 28A is not limited to three, and may be one, two, four or more.

[0024] The fifth joint 35 is connected to the fourth joint 34, i.e., the second end 28A2 of the bogie-side arm adjustment unit 28A. The fifth joint 35 has a fifth rotation axis J5 that is perpendicular to the fourth rotation axis J4.

[0025] The sixth joint 36 is connected to the fifth joint 35. The sixth joint 36 has a sixth rotation axis J6 perpendicular to the fifth rotation axis J5, and is connected to the fifth joint 35. A link having a length may be interposed between the fourth joint 34 and the fifth joint 35. A link having a length may be interposed between the fifth joint 35 and the sixth joint 36. In other words, the fifth joint 35 and the sixth joint 36 are included in the intermediate arm adjustment unit 28B, and the sixth joint 36 is located on the opposite side of the fifth joint 35 to the bogie-side arm adjustment unit 28A.

[0026] 4, in the arm portion 28, the intermediate arm adjustment portion 28B is a portion that includes a fifth joint 35 and a sixth joint 36. The fifth joint 35 is a third end portion 28B3 of the intermediate arm adjustment portion 28B, and is connected to a second end portion 28A2 of the bogie-side arm adjustment portion 28A. The sixth joint 36 is a fourth end portion 28B4 of the intermediate arm adjustment portion 28B.

[0027] One end of the third link 43 is connected to the fourth end 28B4 of the intermediate arm adjustment part 28B, i.e., the sixth joint 36. A seventh joint 37 having a seventh rotation axis J7 is connected to the other end of the third link 43. In the illustrated example, the seventh rotation axis J7 is parallel to the sixth rotation axis J6.

[0028] The eighth joint 38 has an eighth rotation axis J8 perpendicular to the seventh rotation axis J7 and is connected to the seventh joint 37. The seventh joint 37 and the eighth joint 38 are joints equivalent to a wrist. It is not essential to have a joint equivalent to a wrist, but from the viewpoint of object manipulation, it is preferable to have two joints whose rotation axes are oriented perpendicular to each other. The directions of the rotation axes of the two joints may be different from the directions of the seventh rotation axis J7 and the eighth rotation axis J8.

[0029] The hand 50 is connected to the eighth joint 38. The hand 50 is an element that performs a predetermined operation or processing on an object, and is an example of an end effector. The specific structure of the hand 50 is not limited as long as the hand 50 is capable of performing such a predetermined operation or processing on an object. For example, the hand 50 is configured to be able to grasp an object.

[0030] As shown in FIG. 4, in the arm section 28, the distal arm region 28C is a portion including the third link 43, the seventh joint 37, the eighth joint 38, and the hand 50.

[0031] The arm portion 28 is provided with an imaging device 60. The imaging device 60 is provided in the vicinity of the fourth joint 34. The imaging device 60 may be a type that captures still images, or a type that captures moving images.

[0032] FIG. 2 is a block diagram showing the hardware configuration of a control unit 70 that controls the operation of the mobile robot 26.

[0033] The control unit 70 includes a computer 140. The computer 140 includes a processor 142, a memory 144, a storage 146, an input device 148, an output device 150, a storage medium reading device 152, and a communication I / F (Interface) 154. Each of these elements is connected to each other via a bus 156 so as to be able to communicate with each other.

[0034] The storage 146 stores a control program 158 for controlling the mobile robot 26. The processor 142 can execute various programs and control each element. Specifically, the processor 142 reads a program from the storage 146 and executes the program using the memory 144 as a working area. That is, the processor 142 controls each element and performs various calculation processes according to the program stored in the storage 146.

[0035] The memory 144 can temporarily store programs and various data as a working area.

[0036] The storage 146 is, for example, a Read Only Memory (ROM), a Hard Disc Drive (HDD), a Solid State Drive (SSD), etc., and stores various programs and various data. These programs include not only application programs such as the above-mentioned control programs, but also an operating system.

[0037] The input device 148 is a device for performing various inputs to the computer 140. The input device 148 includes operation switches, operation buttons, etc., and may also include pointing devices such as a keyboard and a mouse used in a personal computer, etc.

[0038] The output device 150 is a device for outputting various types of information from the computer 140, and includes, for example, a display, an indicator lamp, a speaker, etc. A touch panel display can also be used as the output device 150, in which case the touch panel display also functions as the input device 148.

[0039] The input device 148 and the output device 150 may be detachable when operating the mobile robot 26. Without the input device 148 and the output device 150, operation commands and other information for the mobile robot 26 may be input and the operation status and other information for the mobile robot 26 may be output by wireless communication via the communication I / F 154.

[0040] The storage medium reader 152 is a device that reads data stored in various storage media and writes data to the storage media. Examples of storage media include a CD (Compact Disc)-ROM, a DVD (Digital Versatile Disc)-ROM, a Blu-ray disc, and a USB (Universal Serial Bus) memory.

[0041] The communication I / F 154 is an interface for communicating with other devices. For communication, standards such as Ethernet (registered trademark) and FDDI (Fiber Distributed Data Interface) are used.

[0042] The above-mentioned joints, hand 50, and drive wheel 24A are controlled by the control unit 70. Specifically, for example, each joint rotates about its own rotation axis as a result of a drive source (not shown) being controlled by the control unit 70. Similarly, the hand 50 also has a drive source (not shown) controlled by the control unit 70 to perform a predetermined operation or processing on an object. The drive wheel 24A rotates as a rotation drive source (not shown) is controlled by the control unit 70.

[0043] In the following, the forward direction, backward direction, left and right directions of the mobile robot 26 as shown in FIG. 5 are defined as follows. Forward direction: a direction along the X-axis determined based on the carriage portion 22 and directed from the driving wheels 24A to the driven wheels 24B Backward: The opposite direction to forward. Left / right direction: The direction that forms 90 degrees with the forward direction and the vertical direction (left direction is the left direction when facing forward)

[0044] In the mobile robot 26 of this embodiment, the distal arm region 28C can be moved left and right by rotating the fifth joint 35 or the sixth joint 36.

[0045] Next, the movement and action of the mobile robot 26 of this embodiment will be described. In the drawings explaining the movement of the mobile robot 26, the symbols shown in Figs. 3A to 3C are used. In the examples shown in Figs. 2A to 2C, a joint 30 and a link 40 are illustrated as representative of various joints and links. Each symbol indicates that the link 40 rotates in the direction of arrow R1 around the joint 30.

[0046] Figure 3D is a representation of the joint 30 and link 40 corresponding to Figure 3C in accordance with the JIS standard. As shown in Figure 3D, in the JIS standard, the line segment of the link 40 extending in a direction perpendicular to the rotation axis of the joint 30 is represented by connecting it to a short line segment indicating the rotation axis via a broken line. To simplify this, in Figure 3C, the line segment of the link 40 is connected to the external shape of the figure of the joint 30.

[0047] In Fig. 4 and Fig. 5, the mobile robot 26 is represented using the joints and links shown in Fig. 3A to Fig. 3C. In Fig. 4 and Fig. 5, the connection order of each joint and each link, the direction of the rotation axis of each joint, and the direction of each link are correctly represented. However, the three-dimensional position of each joint and each link is not necessarily correctly represented. For example, referring to Fig. 1, it can be seen that the link 41 and the link 42 are separated from each other in the Y direction and are not on the same plane, but in Fig. 5, the link 41 and the link 42 are represented as if they are on the same plane. In addition, when two joints are connected without a line segment representing a link, the three-dimensional relative positional relationship of the two joints is not specified. For example, in the three-dimensional positional relationship between the fourth joint 34 and the fifth joint 35 in Fig. 4, the fifth joint 35 may be in the X direction, the Y direction, or the Z direction with respect to the fourth joint 34. Regardless of the positional relationship, the direction of the rotation axis J5 of the fifth joint 35 rotates within the XZ plane in conjunction with the rotation of the fourth joint 34.

[0048] In the embodiment of the mobile robot 26, the postures shown in Figures 4 and 5 are set as the representative postures. These representative postures have the following characteristics. (1) The second rotation axis J2, the third rotation axis J3, and the fourth rotation axis J4 are parallel to the Y axis. (2) The third rotation axis J3 is located behind the second rotation axis J2 in the X-axis direction, and the distal arm region 28C is located forward of the second rotation axis J2. The center of gravity GP1 of the mobile robot 26 is located forward of the center of the cart unit 22 (on the first rotation axis J1) in a plan view.

[0049] As shown in Fig. 6, gravity F1 and inertial force F2 act on the center of gravity GP1 of the entire mobile robot 26. The inertial force F2 is the resultant force of the inertial force caused by the acceleration of the mobile robot 26 in the forward and backward directions, the centrifugal force caused by the turning motion, and the inertial force caused by the movement of the arm unit 28 due to the drive of each of the first joint 31 to the eighth joint 38. The point where the direction of the resultant force F3 of gravity F1 and inertial force F2 intersects with the floor surface LF is called the zero moment point ZMP. When the inertial force F2 becomes large and the zero moment point ZMP reaches the edge of the support area SA, one of the wheels of the mobile robot 26 leaves the floor surface LF and starts to fall over.

[0050] FIG. 7 shows the movement trajectory TL of the center of the carriage unit 22 when the mobile robot 26 turns. In this example, the position of the first rotation axis J1 coincides with the position of the center of the carriage unit 22, but the position of the first rotation axis J1 may be offset from the center of the carriage unit 22. FIGS. 8A to 8H show the change in the rotational position (actual measurement value) of each of the first rotation axis J1 to the eighth rotation axis J8 as a function of time when each joint is controlled so that (1) the position of the zero moment point ZMP does not reach the edge of the support area SA, (2) the error of the posture of the arm unit 28 from the representative posture is reduced, and (3) the error of the position of the hand 50 in the robot coordinate system from the position of the hand 50 in the representative posture is reduced. Here, the weights that the targets (2) and (3) contribute to the determination of the rotational position of each rotation axis are appropriately set. The time ranges in FIGS. 8A to 8H are divided as follows: - Until time T1: Straight driving From time T1 to T2: Turning while gradually reducing the turning radius From time T2 to T3: Turning with a constant turning radius From time T3 to T4: Turning while gradually increasing the turning radius -From time T4: Straight driving In any time range, the forward velocity component is constant.

[0051] As shown in FIG. 4, in the representative posture, the center of gravity GP1 of the arm unit 28 is located away from the first rotation axis J1, specifically, in front of the carriage unit 22 in the traveling direction. In this case, in the mobile robot 26 of this embodiment, as shown in FIG. 9, at the start of turning, the control unit 70 rotates the first joint 31 so that the center of gravity GP1 moves leftward toward the turning center RC. Specifically, as shown in FIG. 8A, from time T1 at the start of turning to time T2, the rotation angle of the first joint 31 gradually increases, and from time T2 to time T3, the rotation angle of the first joint 31 becomes an extreme value, changing from an increase to a decrease. Then, from time T3 to time T4, that is, with the end of turning, the rotation angle of the first joint 31 gradually returns to the rotation angle before the start of turning. The rotation angle of 0 degrees in FIG. 8A is the angle at which the second rotation axis J2, the third rotation axis J3, and the fourth rotation axis J4 are in the Y direction. The control unit 70 controls the first joint 31 in this manner while the mobile robot 26 is turning.

[0052] The control unit 70 further rotates at least one of the fifth joint 35 and the sixth joint 36. As an example, as shown in FIG. 8E and FIG. 8F, from time T1 at the start of turning to time T2, the rotation angles of the fifth joint 35 and the sixth joint 36 gradually increase based on the rotation angle in the representative posture before the start of turning, and from time T2 to time T3, the rotation angle of the fifth joint 35 is approximately constant. Then, from time T3 to time T4, that is, with the end of turning, the rotation angle of the fifth joint 35 gradually returns to the rotation angle before the start of turning. The direction of rotation of the fifth joint 35 and the sixth joint 36 is a direction in which the tip side arm region 28C is moved so as to have a component in the opposite direction to the movement direction of the tip side arm region 28C due to the rotation of the first joint 31. Specifically, during turning, the fifth joint 35 rotates in a direction that moves the tip side arm region 28C away from the turning center RC in the representative posture of FIG. 4. During the pivoting, the sixth joint 36 rotates so that the position of the hand 50 becomes lower in the representative posture of Fig. 4. Such rotation of the sixth joint 36 moves the hand 50 farther from the fifth rotation axis J5, and therefore has the effect of increasing the amount of movement of the hand 50 in the left-right direction (the direction approaching the center of the cart 22 in the Y direction) due to the rotation of the fifth joint 35.

[0053] In this way, the control unit 70 controls the first joint 31 so that the center of gravity position GP1 of the arm unit 28 moves in a direction closer to the rotation center RC than the center of gravity position before the start of rotation when the cart unit 22 rotates, and controls the intermediate arm adjustment unit 28B so that the tip arm region 28C moves in a direction having a component in the opposite direction to the direction of movement of the tip arm region 28C due to the rotation of the first joint 31, compared to when the intermediate arm adjustment unit 28B (fifth joint 35, sixth joint 36) is not operated. This makes it possible to reduce (preferably prevent) the amount of protrusion of the tip arm region 28C (hand 50) from the cart unit 22 in the left-right direction (Y-axis direction) while moving the center of gravity position GP1 of the arm unit 28 toward the rotation center RC. In addition, when the hand 50 runs while holding an object, it is possible to suppress the acceleration applied to the object being held due to the rotation of the first joint 31 to suppress tipping during rotation.

[0054] There are other combinations of rotations of the fifth joint 35 and the sixth joint 36 for moving the tip-side arm region 28C away from the rotation center RC during rotation. In the example shown in FIG. 9, before starting rotation, the fifth joint 35 is rotated 90 degrees from the representative posture to set the sixth rotation axis in the Z direction (vertical direction), and the sixth joint 36 is rotated so that the link 43 faces the X direction (forward direction). When starting rotation, the first joint 31 is rotated counterclockwise in a plan view. This rotation of the first joint 31 acts to move the hand 50 closer to the rotation center RC. At the same time, the sixth joint 36 is rotated in a direction to move the hand 50 so as to cancel the movement of the hand 50 caused by the rotation of the first joint 31 (the link 43 is rotated clockwise in a plan view).

[0055] The expression "the control unit 70 controls the joints so that the mobile robot 26 is in a certain state when turning" (for example, "the first joint 31 is rotated so that the center of gravity GP1 moves to the left where the turning center RC is") does not necessarily mean that rule-based control is being performed, such as controlling the joints to a predetermined angle in response to a condition such as turning. This expression includes calculating the angle that each joint of the arm unit 28 should take at each time in order for the mobile robot 26 to turn along a specified trajectory without falling over, and controlling the joints as a result of the calculation. Figures 8A to 8H show the angle changes of each joint as a result of such calculations, and do not mean that the curves of such angle changes are programmed in advance.

[0056] From the viewpoint of reducing the amount of protrusion of the tip-side arm region 28C, it is not necessary to rotate both the fifth joint 35 and the sixth joint 36, and it may be sufficient to rotate either one of them. In any case, by rotating the joint included in the intermediate arm adjustment part 28B, it is possible to reduce the amount of protrusion of the tip-side arm region 28C.

[0057] In the mobile robot 26 of this embodiment, the control unit 70 further rotates the eighth joint 38 as shown in Fig. 8H. The rotation of the eighth joint 38 adjusts the posture of the hand 50. For example, if the hand 50 is tilted left or right due to the rotation of the fifth joint 35 (and therefore the posture of the object held by the hand 50 is tilted left or right), the rotation of the eighth joint 38 can bring the posture of the hand 50 closer to the posture before the rotation of the fifth joint 35.

[0058] In addition, from the viewpoint of moving the center of gravity GP1 of the arm unit 28 toward the rotation center RC and moving the distal arm region 28C in the opposite direction, the control unit 70 does not need to control each joint other than the first joint 31, the fifth joint 35, and the sixth joint 36 to rotate. In fact, in FIG. 8, the change in the rotation angle of the second joint 32 (FIG. 8B), the third joint 33 (FIG. 8C), the fourth joint 34 (FIG. 8D), and the seventh joint 37 (FIG. 8G) is small. However, other joints may be rotated during the turning movement within a range that does not interfere with the prevention of tipping and the prevention of protrusion of the distal arm region 28C.

[0059] The above example is a case where the center of gravity GP1 of the arm unit 28 is located forward of the first rotation axis J1 in the traveling direction of the cart unit 22. In this case, the control unit 70 controls the first joint 31 so that the center of gravity GP1 of the arm unit 28 moves closer to the center of rotation than the center of gravity position before the start of rotation in a state where the center of gravity GP1 of the arm unit 28 is located forward of the first rotation axis J1 in the traveling direction of the cart unit 22, and controls the intermediate arm adjustment unit 28B so that the tip arm region 28C moves in a direction away from the center of rotation RC compared to a case where the intermediate arm adjustment unit 28B (fifth joint 35, sixth joint 36) is not operated. Such a forward-leaning posture of the arm unit 28 has the effect of preventing the zero moment point ZMP from approaching the rear end of the support area SA during accelerated running in which a backward inertial force is generated.

[0060] Conversely, the center of gravity GP1 of the arm unit 28 may be located rearward of the first rotation axis J1 in the traveling direction of the cart unit 22. In this case, the control unit 70 controls the first joint 31 so that the center of gravity GP1 of the arm unit 28 moves closer to the rotation center RC than the center of gravity position before the start of rotation in a state where the center of gravity GP1 of the arm unit 28 is located rearward of the first rotation axis J1 in the traveling direction of the cart unit, and controls the intermediate arm adjustment unit 28B so that the tip-side arm region 28C moves closer to the rotation center RC compared to when the intermediate arm adjustment unit 28B (fifth joint 35, sixth joint 36) is not operated. Such a backward tilting posture of the arm unit 28 has the effect of preventing the zero moment point ZMP from approaching the front end of the support area SA during deceleration traveling in which a forward inertial force is generated.

[0061] When the arm unit 28 is in a backward tilting position, specifically, the control unit 70 rotates the first joint 31 in the opposite direction to when the arm unit 28 is in a forward tilting position. This causes the center of gravity GP1 of the arm unit 28 to move toward the rotation center RC from the center of gravity position before the start of rotation. This prevents the zero moment point ZMP from approaching the edge of the support area SA in the opposite direction to the rotation center RC, and prevents the mobile robot 26 from falling over.

[0062] The control unit 70 further rotates the fifth joint 35 and the sixth joint 36. The direction of rotation of the fifth joint 35 and the sixth joint 36 when the arm unit 28 is in the backward tilting posture is also the same as when the arm unit 28 is in the forward tilting posture in that the tip arm region 28C moves in a direction having a component in the opposite direction to the direction of movement of the tip arm region 28C due to the rotation of the first joint 31, compared to when the fifth joint 35 and the sixth joint 36 are not rotated. However, this direction is a direction approaching the rotation center RC, and from this point of view, it is the opposite direction to the direction of movement of the tip arm region 28C when the arm unit 28 is in the forward tilting posture.

[0063] The posture of the arm portion 28 during turning, whether the center of gravity GP1 is in front of or behind the first rotation axis J1, may be selected depending on whether accelerating or decelerating is expected before, during, or after turning.

[0064] The following are additional notes regarding this disclosure. (Appendix 1) A bogie section (22); a moving mechanism (24) for rotating the carriage portion (22); an arm portion (28) including: a first joint (31) connected to the bogie portion (22) and having a first rotation axis (J1) in a vertical direction; a bogie-side arm adjustment portion (28A) having a first end (28A1) and a second end (28A2), with the first end (28A1) connected to the first joint (31); an intermediate arm adjustment portion (28B) having a third end (28B3) and a fourth end (28B4), with the third end (28B3) connected to the second end (28A2); and a tip-side arm region (28C) connected to the fourth end (28B4); a control unit (70) that controls the moving mechanism (24) and the arm unit (28); Equipped with The carriage-side arm adjustment unit (28A) includes one joint including one orthogonal rotation axis perpendicular to the first rotation axis (J1), or multiple joints (32, 33, 34) including multiple orthogonal rotation axes (J2, J3, J4) perpendicular to the first rotation axis and parallel to each other, The control unit (70) The mobile robot (26) controls the first joint (31) so that, during the turning travel of the cart unit (22), the center of gravity position (GP1) of the arm unit (28) moves in a direction closer to a turning center (RC) than the center of gravity position before the start of turning, and controls the intermediate arm adjustment unit (28B) so that the tip-side arm region (28C) moves in a direction having a component in the opposite direction to the direction of movement of the tip-side arm region (28C) due to rotation of the first joint (31) compared to a case in which the intermediate arm adjustment unit (28B) is not operated. (Appendix 2) 2. The mobile robot (26) of claim 1, wherein the control unit (70) controls the first joint (31) so that, when the center of gravity position (GP1) of the arm section (28) is located forward in the direction of travel of the cart section (22) relative to the first rotation axis (J1), the center of gravity position (GP1) of the arm section (28) moves in a direction closer to a rotation center than the center of gravity position before the start of rotation, and controls the intermediate arm adjustment unit (28B) so that the tip arm region (28C) moves in a direction away from the rotation center compared to a case in which the intermediate arm adjustment unit (28B) is not operated. (Appendix 3) 2. The mobile robot (26) of claim 1, wherein the control unit (70) controls the first joint (31) so that, when the center of gravity position (GP1) of the arm unit (28) is located rear of the first rotation axis (J1) in the direction of travel of the cart unit (22), the center of gravity position (GP1) of the arm unit (28) moves in a direction closer to a rotation center (RC) than the center of gravity position before start of rotation, and controls the intermediate arm adjustment unit (28B) so that the tip arm region (28C) moves in a direction closer to the rotation center compared to a case in which the intermediate arm adjustment unit (28B) is not operated. (Appendix 4) The mobile robot (26) according to any one of Appendices 1 to 3, wherein the intermediate arm adjustment unit (28B) includes a fifth joint (35) having a fifth rotation axis (J5) perpendicular to the orthogonal rotation axis (J2, J3, J4), and a sixth joint (36) having a sixth rotation axis (J6) perpendicular to the fifth rotation axis (J5) and located on the opposite side of the cart-side arm adjustment unit (28A) from the fifth joint (35). (Appendix 5) The carriage side arm adjustment unit (28A) is a second joint (32) connected to the first joint (31) without any other joint therebetween and having a second rotation axis (J2) perpendicular to the first rotation axis (J1); a first link (41) having one end connected to the second joint (32) and having a length in a direction perpendicular to the second rotation axis (J2); a third joint (33) provided at the other end of the first link (41) and having a third rotation axis (J3) parallel to the second rotation axis (J2); a second link (42) having one end connected to the third joint (33) and having a length in a direction perpendicular to the third rotation axis (J3); a fourth joint (34) provided at the other end of the second link (42) and having a fourth rotation axis (J4) parallel to the third rotation axis (J3); The mobile robot (26) according to any one of claims 1 to 4, [Explanation of symbols]

[0065] 22 Bogie section 24 Moving mechanism 26 Mobile Robot 28 Arm section 28A Carriage side arm adjustment part 28A1 First end of the trolley side arm adjustment part 28A2 Second end of the trolley-side arm adjustment part 28B Intermediate arm adjustment part 28B3 Third end of intermediate arm adjustment part 28B4 Fourth end of intermediate arm adjustment part 28C Tip arm area 31 First joint 32 Second joint 33 Third joint 34 Fourth joint 35 Fifth joint 36 Sixth joint 37 Seventh joint 38 Eighth joint 41 First Link 42 Second Link 43 Third Link 50 hands 70 Control section GP1 Center of gravity of arm J1 First rotation axis J2 Second rotation axis J3 Third rotation axis J4 Fourth rotation axis J5 Fifth rotation axis J6 Sixth rotation axis J7 Seventh rotation axis J8 8th rotation axis

Claims

1. A trolley section, A moving mechanism for rotating the carriage unit; an arm section including: a first joint connected to the carriage section and having a first rotation axis in a vertical direction; a carriage-side arm adjustment section having a first end and a second end, the first end being connected to the first joint; an intermediate arm adjustment section having a third end and a fourth end, the third end being connected to the second end; and a tip-side arm region connected to the fourth end; A control unit that controls the moving mechanism and the arm unit; Equipped with The carriage-side arm adjustment unit includes one joint including one orthogonal rotation axis perpendicular to the first rotation axis, or a plurality of joints each including a plurality of orthogonal rotation axes perpendicular to the first rotation axis and parallel to each other, The control unit is a control unit for controlling the first joint so that, during a turning motion of the carriage unit, the center of gravity of the arm unit moves in a direction closer to a center of turning than the center of gravity position before turning begins, and a control unit for controlling the intermediate arm adjustment unit so that the tip-side arm region moves in a direction having a component opposite to the direction of movement of the tip-side arm region due to rotation of the first joint, compared to a case in which the intermediate arm adjustment unit is not operated.

2. 2. The mobile robot of claim 1, wherein the control unit controls the first joint so that, while the center of gravity of the arm unit is located forward of the first rotation axis in the direction of travel of the cart unit, the center of gravity of the arm unit moves in a direction closer to a center of rotation than the center of gravity of the arm unit before start of rotation, and controls the middle arm adjustment unit so that the tip-side arm region moves in a direction away from the center of rotation compared to a case in which the middle arm adjustment unit is not operated.

3. 2. The mobile robot of claim 1, wherein the control unit controls the first joint so that, while the center of gravity of the arm unit is located rearward of the first rotation axis in the direction of travel of the cart unit, the center of gravity of the arm unit moves in a direction closer to a rotation center than the center of gravity position before start of rotation, and controls the middle arm adjustment unit so that the tip-side arm region moves toward the rotation center compared to a case in which the middle arm adjustment unit is not operated.

4. 2. The mobile robot of claim 1, wherein the intermediate arm adjustment unit includes a fifth joint having a fifth rotation axis perpendicular to the orthogonal rotation axis, and a sixth joint having a sixth rotation axis perpendicular to the fifth rotation axis, the sixth joint being on an opposite side of the cart-side arm adjustment unit from the fifth joint.

5. The carriage side arm adjustment unit is A second joint is connected to the first joint without any other joint therebetween and has a second rotation axis perpendicular to the first rotation axis; a first link having one end connected to the second joint and having a length in a direction perpendicular to the second rotation axis; a third joint provided at the other end of the first link and having a third rotation axis parallel to the second rotation axis; a second link having one end connected to the third joint and having a length in a direction perpendicular to the third rotation axis; a fourth joint provided at the other end of the second link and having a fourth rotation axis parallel to the third rotation axis; 10. The mobile robot of claim 1 , comprising:

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