Robot System

Abstract

To provide a robot system capable of preventing tipping over while suppressing a decrease in the operating rate. [Solution] The robot system 1 includes a robot 2 having a base 21, an arm 22 connected to the base 21, and a hand 23 attached to the arm 22, a main body 3 on which the base 21 is installed, and a control device 4 that controls the operation of the robot 2. When the robot 2 performs an operation of pulling the hand 21 diagonally upward toward the main body 3, the control device 4 controls the operation of the robot 2 to prioritize horizontal movement over vertical movement, or when the robot 2 performs an operation of pushing the hand 21 diagonally downward away from the main body 3, the control device 4 controls the operation of the robot 2 to prioritize vertical movement over horizontal movement, thereby preventing the main body 3 from tipping over.

Description

[Technical Field]

[0001] The present invention relates to a robot system that performs at least one of loading and unloading of workpieces. [Background technology]

[0002] At production sites, logistics sites, etc., robot systems are used to load and unload workpieces, such as stacking workpieces onto pallets (also called palletizing) and unloading workpieces from pallets (also called depalletizing). Patent Document 1 discloses a transport mobile robot system having a robot arm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-97064 Summary of the Invention [Problem to be solved by the invention]

[0004] Because a mobile transport robot system like the one in Patent Document 1 is not fixed to the floor, there is a risk of the robot arm tipping over if it is moved at high speed while holding a heavy workpiece. Therefore, it is necessary to operate the robot arm in a way that prevents it from tipping over, but simply moving the robot arm at a slow speed would significantly reduce the operating rate.

[0005] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a robot system that can prevent tipping over while suppressing a decrease in the operating rate. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention is a robot system that performs at least one of loading and unloading of workpieces, comprising a robot having a base, an arm connected to the base, and a hand attached to the arm, a main body on which the base is mounted, and a control device that controls the operation of the robot, wherein the control device controls the operation of the robot to prioritize horizontal movement over vertical movement when the robot performs an operation of pulling the hand diagonally upward toward the main body, or controls the operation of the robot to prioritize vertical movement over horizontal movement when the robot performs an operation of pushing the hand diagonally downward away from the main body, thereby preventing the main body from tipping over.

[0007] The control device may pre-store a non-tip condition equation including a first rotational moment acting on the main body's tipping fulcrum due to gravity acting on a first center of gravity of the main body and the base, a second rotational moment acting on the main body's tipping fulcrum due to gravity acting on a second center of gravity of the workpiece, the arm, and the hand, a third rotational moment acting on the main body's tipping fulcrum due to vertical acceleration movement of the second center of gravity, and a fourth rotational moment acting on the main body's tipping fulcrum due to horizontal acceleration movement of the second center of gravity, and may generate provisional motion data of the second center of gravity from the current position to the target position without considering tipping of the main body, define the horizontal acceleration of the second center of gravity related to the provisional motion data as provisional horizontal acceleration, and define the vertical acceleration of the second center of gravity related to the provisional motion data as provisional vertical acceleration, and if the provisional horizontal acceleration and the provisional vertical acceleration do not satisfy the non-tip condition equation, correct at least the provisional vertical acceleration to generate final motion data.

[0008] Furthermore, if the non-overturning condition equation is satisfied when the horizontal acceleration of the second center of gravity is the provisional horizontal acceleration and the vertical acceleration of the second center of gravity is 0, the control device may not correct the provisional horizontal acceleration and correct the provisional vertical acceleration to a maximum value that satisfies the non-overturning condition equation, and if the non-overturning condition equation is not satisfied when the horizontal acceleration of the second center of gravity is the provisional horizontal acceleration and the vertical acceleration of the second center of gravity is 0, the control device may correct the provisional horizontal acceleration to a maximum value that satisfies the non-overturning condition equation and correct the provisional vertical acceleration to 0. [Effects of the Invention]

[0009] The present invention provides a robot system that can prevent tipping over while suppressing a decrease in operating rate. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a side view showing an overall configuration of a robot system according to an embodiment of the present invention. [Figure 2] Block diagram showing the hardware configuration of the robot system in Figure 1 [Figure 3] Schematic diagram for explaining the movement and tipping fulcrum of the robot of FIG. 1 during the lifting operation. [Figure 4] Graph showing the path of the second center of gravity of the robot system of FIG. 1 during a lifting operation [Figure 5] 1. A flowchart showing an example of a process flow realized by the control device of FIG. 1 during a lifting operation. [Figure 6] Schematic diagram for explaining the movement and tipping fulcrum of the robot of FIG. 1 during a push-down operation. [Figure 7] 1. A flowchart showing an example of a process flow realized by the control device of FIG. 1 during a pressing operation. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present invention will be described in detail below with reference to the drawings. The embodiment of the present invention relates to a robot system that loads and unloads workpieces. In the following, an automated guided vehicle (AGV) equipped with a robot will be used as an example of the robot system. However, the present invention can also be applied to a robot system that does not move.

[0012] First Embodiment Fig. 1 is a side view showing the overall configuration of a robot system according to an embodiment of the present invention. As shown in Fig. 1, the robot system 1 includes a robot 2, a main body 3 on which the robot 2 is installed, and a control device 4 that controls the operation of the robot 2, and performs at least one of loading and unloading of workpieces W.

[0013] The robot 2 has a base 21 mounted on the main body 3, an arm 22 connected to the base 21, and a hand 23 attached to the arm 22. The arm 22 is composed of a link mechanism having multiple links and has joints that connect the links. Each joint is provided with a drive motor (not shown). An example of the robot 2 is a vertical articulated robot with six joints. However, the present invention is also applicable to robots with five or fewer or seven or more joints, horizontal articulated robots, etc. The hand 23 has a gripping portion that grips a workpiece, such as a transported object.

[0014] The shape of the main body 3 has a front-rear direction, a left-right direction perpendicular to the front-rear direction, and a top-bottom direction perpendicular to the front-rear and left-right directions, and is, for example, a substantially rectangular parallelepiped. The top surface 31 of the main body 3 is a platform on which workpieces can be loaded, and is, for example, a substantially rectangular shape. The main body 3 has four wheels, a left front wheel 32a, a right front wheel 32b, a left rear wheel 32c, and a right rear wheel 32d, at both the front and rear ends, respectively, and is a mobile automated guided vehicle. The drive system for travel is not limited. The wheels may be omniwheels or crawlers, as long as they have a contact point with the floor surface. The number of wheels is not limited to four, and may be three, five, or more.

[0015] The base 21 of the robot 2 is installed at the end of the upper surface 31 of the main body 3, thereby making effective use of the reach length of the arm 22. However, the location where the robot 2 is installed is not limited.

[0016] The control device 4 is mounted inside the main body 3. There may be one or more control devices 4. In the case of more than one control device 4, the control devices 4 are connected to each other so that they can communicate with each other. In the following description, it is assumed that there is one control device 4, and that one control device 4 controls the operation of the robot 2 and the main body 3 as an automatic guided vehicle.

[0017] 2 is a block diagram showing the hardware configuration of the robot system of FIG. 1. The robot 2 has an input / output interface 24, a sensor 25, and an actuator 26. The input / output interface 24 receives signals from the control device 4 and outputs signals to the control device 4. The sensor 25 is, for example, an encoder, which detects the rotation speed and rotation angle of the rotation shaft of each drive motor and outputs sensor data to the control device 4. The actuator 26 is, for example, a drive motor for the joints of the arm 22 or the gripping portion of the hand 23, and drives the joints and gripping portion in accordance with command signals from the control device 4. The sensor 25 and the actuator 26 are not limited to these examples.

[0018] The main body 3 has an input / output interface 33, a sensor 34, and an actuator 35. The input / output interface 33 receives signals from the control device 4 and outputs signals to the control device 4. The sensor 34 is, for example, a magnetic sensor or an optical sensor, and detects guide wires (not shown) formed on the floor surface, and outputs sensor data to the control device 4. The actuator 35 is, for example, a drive motor, and drives the wheels of the main body 3 in accordance with command signals from the control device 4. The sensor 34 and the actuator 35 are not limited to these examples.

[0019] The CPU (Central Processing Unit) 41, memory 42, auxiliary storage device 43, and input / output interface 44 of the control device 4 are connected via a bus 45. The CPU 41 reads a control program stored in advance in the auxiliary storage device 43 or the like into the memory 42 and sequentially executes a plurality of commands. The auxiliary storage device 43 is a hard disk drive, a solid state drive, or the like, and stores data used in the processing described below. The input / output interface 44 inputs signals from the robot 2, the main body 3, other devices, and the like, and outputs signals to them. Note that all or part of the functions of the control device 4 may be configured using logic circuits or analog circuits, and the processing of various programs may be configured using electronic circuits such as an FPGA (Field Programmable Gate Array).

[0020] 3 is a schematic diagram for explaining the operation and tipping fulcrum of the robot of FIG. 1 during a lifting operation. In the example shown in FIG. 3, a workpiece W is placed on the floor. The robot 2 performs an operation (hereinafter referred to as "lifting operation B") in which the hand 23 grips the workpiece W from a starting point s to a target point e (hereinafter referred to as "gripping state A"), and then lifts the hand 23 obliquely upward toward the main body 3.

[0021] In the grasping state A, the center of gravity of the entire robot system 1 shifts to the front of the main body 3 (= right side in the figure), reducing the stability of the main body 3. Furthermore, when the robot 2 performs the lifting operation B in the grasping state A, the stability of the main body 3 further decreases, increasing the possibility that it will tilt forward and tip over in the tipping direction (= clockwise direction) shown in Figure 3.

[0022] In the example shown in Figure 3, the tipping fulcrum O for the main body 3 forward is the contact point between the left front wheel 32a and the right front wheel 32b and the floor surface. Consider an XY coordinate space with this tipping fulcrum O as the origin, the front-to-back direction of the robot system 1 (= left-to-right direction in the figure) as the X axis, and the up-down direction of the robot system 1 (= up-to-down direction in the figure) as the Y axis. The X axis is the horizontal direction, and the Y axis is the vertical direction. The coordinates of the start point s are (Xs, Ys), and the coordinates of the target point e are (Xe, Ye).

[0023] The weight of the main body 3 and the base 21 is Wb, and the coordinates of the center of gravity of the main body 3 and the base 21 (hereinafter referred to as the "first center of gravity") are (Xb, Yb). Furthermore, the weight of the workpiece W, the arm 22, and the hand 23 is Wm, and the coordinates of the center of gravity of the workpiece W, the arm 22, and the hand 23 at time t (hereinafter referred to as the "second center of gravity") are (X(t), Y(t)). While the robot 2 is performing the lifting operation B, the coordinates (Xb, Yb) of the first center of gravity do not change, but the coordinates (X(t), Y(t)) of the second center of gravity do change. Furthermore, while the robot 2 is performing the lifting operation B, Xb is negative, and Yb, X(t), and Y(t) are positive.

[0024] Figure 4 is a graph showing the path of the second center of gravity of the robot system in Figure 1 during a lifting operation. The horizontal acceleration of the second center of gravity at time t is ax(t), and the vertical acceleration is ay(t). Here, ax(t) is positive in the horizontal forward direction (= direction away from the main body 3, direction moving from left to right in the figure), and ay(t) is positive in the vertical upward direction (= direction moving from bottom to top in the figure). The magnitude of the gravitational acceleration is 9.8 [m / s^2] (s^2 represents s squared).

[0025] In the examples of Figures 3 and 4, there are four rotational moments acting on the tipping fulcrum O of the main body 3. The first rotational moment acts on the tipping fulcrum O of the main body 3 due to the force of gravity acting on the first center of gravity shown in Figure 3. The formula for the first rotational moment is 9.8·Wb·|Xb| (Wb>0, |Xb| represents the absolute value of Xb). The first rotational moment acts on the tipping fulcrum O in the direction opposite to the tipping direction of the main body 3 during the lifting motion B.

[0026] The second rotational moment acts on the tipping fulcrum O of the main body 3 due to gravity acting on the second center of gravity shown in Figure 3. The formula for the second rotational moment is 9.8 Wm X(t) (Wm, X(t)>0). The second rotational moment acts on the tipping fulcrum O in the tipping direction of the main body 3 during the lifting motion B.

[0027] The third rotational moment acts on the tipping fulcrum O of the body 3 due to the vertical acceleration movement of the second center of gravity shown in Figure 4. The formula for the third rotational moment is Wm X(t) ay(t) (Wm, X(t)>0). During the lifting motion B, if ay(t) is positive, the third rotational moment acts on the tipping fulcrum O in the tipping direction of the body 3, and if ay(t) is negative, the third rotational moment acts on the tipping fulcrum O in the opposite direction to the tipping direction of the body 3.

[0028] The fourth rotational moment acts on the tipping fulcrum O of the body 3 due to the horizontal acceleration movement of the second center of gravity shown in Figure 4. The formula for the fourth rotational moment is Wm·Y(t)·ax(t) (Wm, Y(t)>0). During the lifting motion B, if ax(t) is positive, the fourth rotational moment acts on the tipping fulcrum O in the direction opposite to the tipping direction of the body 3, and if ax(t) is negative, the fourth rotational moment acts on the tipping fulcrum O in the tipping direction of the body 3.

[0029] Considering the four rotational moments acting on the tipping fulcrum O of the main body 3, in order for the robot 2 to stably perform the lifting operation B without tipping over, the following non-tipping condition formula must be satisfied.

[0030]

number

[0031] Here, S (S>0) is a safety constant, which is a buffer amount for designing on the safe side. Note that equation (1) can be transformed into the following equation using a safety coefficient K (K>1).

[0032]

number

[0033] The following describes equation (1), but the same applies to equation (2). One possible way to satisfy equation (1) is to increase Wb. For example, increasing the weight of the main body 3 is one way to increase Wb. Another possible solution is to increase the size of the main body 3 in a plan view from above in the vertical direction, thereby increasing the distance from the left front wheel 32a and the right front wheel 32b to the first center of gravity. However, these designs can cause problems, such as increased power consumption and floor wear due to the increased weight of the main body 3, and increased required aisle width and reduced effective floor area due to the increased size of the main body 3. Another possible solution is to control the arm 22 to operate at a slow speed. However, simply operating the arm 22 at a slow speed would significantly reduce the availability of the robot 2. Therefore, in this embodiment, the control device 4 is devised to control the operation of the robot 2, thereby preventing the main body 3 from tipping over while minimizing a decrease in the availability of the robot 2.

[0034] The shortest path of the second center of gravity from the start point s to the target point e is the first path R1. However, moving the arm 22 at high speed on the first path R1 poses a risk of tipping over. Because the value of the left side of equation (1) does not change during the lifting operation B, we consider controlling the value of the right side to satisfy the inequality and prevent tipping over. Specifically, when performing the lifting operation B, the control device 4 controls the operation of the robot 2 to slowly accelerate horizontally near the start point s where there is a risk of tipping over, and to prioritize horizontal movement over vertical movement, thereby preventing tipping over of the main body 3.

[0035] When the control device 4 controls the movement of the robot 2 in this manner, the path of the second center of gravity from the start point s to the target point e becomes the second path R2. Near the start point s, the value of X(t) is large, so the value of the first term on the right-hand side of equation (1) is large. However, the value of ax(t) is large and the value of ay(t) is small, so the right-hand side of equation (1) as a whole is small. Also, near the target point e, the value of X(t) is small, so the values ​​of the first and second terms on the right-hand side of equation (1) are small, and the right-hand side of equation (1) as a whole is also small. This makes it possible to prevent the main body 3 from tipping over while suppressing a decrease in the operating rate of the robot 2 while the robot 2 is performing the lifting operation B.

[0036] Figure 5 is a flowchart showing an example of the flow of processing performed by the control device of Figure 1 during the lifting operation. In the following, it is assumed that the robot 2 can output the same amount of force (acceleration) in all directions at all locations without bias, and can achieve the same maximum speed. In situations where there is a high risk of the main body 3 tipping over, the robot 2 is considered to fully meet these conditions.

[0037] To give an overview of FIG. 5, the control device 4 generates provisional motion data at each time point during the lifting motion B by the robot 2, and if the provisional motion data does not satisfy the non-tipping condition formula (1), corrects the provisional motion data and generates final motion data. The provisional motion data is a provisional path from the current position to the target position e, calculated on the assumption that the main body 3 will not tip over, and a provisional acceleration of the second center of gravity (= the center of gravity of the workpiece W, arm 22, and hand 23) for realizing the provisional path. The final motion data is a final path from the current position to the target position e, and a final acceleration of the second center of gravity for realizing the final path. Based on the final motion data, the control device 4 calculates control data for the robot 2 at each time point (such as the drive amount of the drive motor of each joint) and controls the movement of the robot 2.

[0038] Hereinafter, the horizontal acceleration of the second center of gravity related to the provisional motion data will be referred to as provisional horizontal acceleration aPx, the vertical acceleration of the second center of gravity related to the provisional motion data will be referred to as provisional vertical acceleration aPy, the horizontal acceleration of the second center of gravity related to the final motion data will be referred to as final horizontal acceleration aCx, and the vertical acceleration of the second center of gravity related to the final motion data will be referred to as final vertical acceleration aCy.

[0039] 5, the control device 4 generates provisional motion data including a provisional route and provisional acceleration from the current position (X(t), Y(t)) to the target point e (Xe, Ye) without considering the tipping over of the main body 3 (step S1). The provisional route is, for example, the shortest route from the current position to the target point e, but may also satisfy other conditions or a combination of multiple conditions.

[0040] To execute step S1, the control device 4 stores in advance the weight, dimensions, link parameters, etc. of each part of the robot 2 in the memory 42 or the auxiliary storage device 43. Link parameters are known to be expressed using the Denavit-Hartenberg notation (DH method), and are also called DH parameters. The control device 4 executes a forward kinematic calculation using the values ​​of the link parameters to analytically calculate the position of each part of the robot 2. The control device 5 then calculates the position of the second center of gravity on the provisional path, and calculates the provisional horizontal acceleration aPx and provisional vertical acceleration aPy.

[0041] Next, the control device 4 checks whether the provisional horizontal acceleration aPx and provisional vertical acceleration aPy calculated in step S1 satisfy the non-overturn condition formula (1) (step S2). Specifically, the control device 4 substitutes the value of the provisional horizontal acceleration aPx for the horizontal acceleration ax(t) of the second center of gravity and the value of the provisional vertical acceleration aPy for the vertical acceleration ay(t) of the second center of gravity in formula (1), and checks whether the inequality is satisfied. To execute step S2, the control device 4 stores the non-overturn condition formula (1) in advance in the memory 42 or the auxiliary storage device 43.

[0042] If the provisional horizontal acceleration aPx and the provisional vertical acceleration aPy satisfy the non-overturn conditional expression (Yes in step S2), the control device 4 does not correct the provisional motion data, but sets it as the final motion data as is. That is, the control device 4 sets aCx=aPx and aCy=aPy, and generates the final motion data (step S3).

[0043] If the provisional horizontal acceleration aPx and the provisional vertical acceleration aPy do not satisfy the non-overturn conditional expression (No in step S2), the control device 4 corrects at least the provisional vertical acceleration aPy to a smaller value and generates final motion data. In this case, the process of generating final motion data is divided into two steps, steps S5 and S6.

[0044] If the main body 3 does not tip over due to the provisional horizontal acceleration aPx alone (Yes in step S4), the control device 4 does not correct the provisional horizontal acceleration aPx, but corrects the provisional vertical acceleration aPy to the maximum value that satisfies the non-tipping condition equation of equation (1) (provided that ax(t) = aPx in equation (1)), and generates final operation data (step S5). "If the main body 3 does not tip over due to the provisional horizontal acceleration aPx alone" refers to the case where the non-tipping condition equation of equation (1) is satisfied when the horizontal acceleration ax(t) of the second center of gravity is the provisional horizontal acceleration aPx and the vertical acceleration ay(t) of the second center of gravity is 0.

[0045] If the main body 3 would tip over due to the provisional horizontal acceleration aPx alone (No in step S4), the control device 4 corrects the provisional horizontal acceleration aPx to the maximum value that satisfies the non-tipping condition equation of equation (1) (provided that ay(t) in equation (1) = 0), corrects the provisional vertical acceleration aPy to 0, and generates final motion data (step S6). "If the main body 3 would tip over due to the provisional horizontal acceleration aPx alone" refers to a case where the non-tipping condition equation of equation (1) is not satisfied when the horizontal acceleration ax(t) of the second center of gravity is the provisional horizontal acceleration aPx and the vertical acceleration ay(t) of the second center of gravity is 0.

[0046] The control device 4 controls the movement of the robot 2 based on the value of the confirmed movement data generated in any of steps S3, S5, or S6 (step S7). Next, the control device 4 checks whether the robot 2 has reached the target point e (Xe, Ye) (step S8). If the robot 2 has reached the target point e (Xe, Ye) (Yes in step S8), the control device 4 ends the process. If the robot 2 has not reached the target point e (No in step S8), the control device 4 proceeds to the next time (step S9) and repeats the process from step S1.

[0047] By executing the process shown in FIG. 5, the control device 4 can control the movement of the robot 2 so that, when there is a risk of the robot 2 falling over, it prioritizes horizontal movement over vertical movement.

[0048] In the above description, the control device 4 controls the movement of the robot 2 in step S7, but the processes other than step S7 may be performed in advance. In this case, the control device 4 stores the confirmed movement data for each time that is generated in advance. Then, the control device 4 controls the movement of the robot 2 based on the stored confirmed movement data for each time.

[0049] Furthermore, in the above explanation, an example was given in which the robot 2 performs the lifting operation B in the gripping state A, but the present invention can also be applied to the reverse operation. That is, the present invention can also be applied to an operation in which the robot 2 pushes the hand 23 diagonally downward in a direction away from the main body 3 when the hand 23 is in a state in which the hand 23 is gripping the workpiece W (= gripping state A) (hereinafter referred to as "pushing-down operation C").

[0050] 6 is a schematic diagram for explaining the motion and tipping fulcrum of the robot of FIG. 1 during a push-down motion. The tip-down fulcrum O for the forward motion of the main body 3 is the contact point between the left front wheel 32a and the right front wheel 32b and the floor surface, as in the example shown in FIG. 3. The start point s2 and the target point e2 are at the opposite coordinates to the start point s and the target point e in FIG. 3. In the processing of FIG. 7, which will be described later, the robot 2 performs a push-down motion C in a gripping state A from the start point s2 to the target point e2.

[0051] Fig. 7 is a flowchart showing an example of the flow of processing in a push-down operation realized by the control device of Fig. 1. In order for the robot 2 to safely and quickly perform the push-down operation C, the control device 4 does not sequentially calculate the operation data while controlling the operation of the robot 2, but rather pre-calculates the operation data for all time points and then controls the operation of the robot 2.

[0052] As shown in Fig. 7, the control device 4 swaps the calculated start point s2 and the target point e2 (step S11). That is, the control device 4 sets the start point s2 to the target point e in Fig. 3, and the target point e2 to the start point s in Fig. 3. Next, the control device 4 performs a pre-calculation process for the motion data using the same process as Fig. 5 (except for step S7), and stores the generated confirmed motion data for each time (step S12). Then, the control device 4 controls the motion of the robot 2 in the reverse order of the stored confirmed motion data for each time (step S13).

[0053] When the control device 4 executes the flowchart of Fig. 7, the second center of gravity moves along the second route R2 from the start point s2 toward the target point e2 of Fig. 6. That is, when the robot 2 performs the push-down motion C, the control device 4 controls the operation of the robot 2 so that it quickly accelerates in the vertical direction near the start point s2 where there is no risk of tipping over, and prioritizes vertical movement over horizontal movement, and then slowly decelerates in the horizontal direction at the target point e2 where there is a risk of tipping over, thereby preventing the main body 3 from tipping over.

[0054] The lifting operation B is included in the operation of unloading the workpiece W from the pallet, and is an operation that carries a high risk of tipping over of the main body 3. The pushing operation C is included in the operation of loading the workpiece W onto the pallet, and is an operation that carries a high risk of tipping over of the main body 3. According to the robot system 1 of this embodiment, tipping over can be prevented while minimizing a decrease in the operating rate during the operation of loading and unloading the workpiece W.

[0055] The present invention is applicable to the lifting operation B or the pushing operation C by the robot 2 even when the hand 23 is not gripping the workpiece W. In this case, the control device 4 calculates the weight and position of the second center of gravity as if the workpiece W is not present, and executes the processing shown in FIG.

[0056] While the preferred embodiments of the robot system and the like according to the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas disclosed herein, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0057] 1. Robot system 2. Robot 3...Main body 4. Control device 21...Bass 22...Arm 23...Hand O………Fulcrum W...Work aPx……Provisional horizontal acceleration aPy: Provisional vertical acceleration aCx……determined horizontal acceleration aCy: Determined vertical acceleration

Claims

1. A robot system that performs at least one of loading and unloading of workpieces, a robot having a base, an arm connected to the base, and a hand attached to the arm; a main body on which the base is mounted; a control device for controlling the operation of the robot; Equipped with The control device controls the operation of the robot so that when the robot performs an operation of lifting the hand diagonally upward toward the main body, it prioritizes horizontal movement over vertical movement, or when the robot performs an operation of pushing the hand diagonally downward away from the main body, it prioritizes vertical movement over horizontal movement, thereby preventing the main body from tipping over. A robot system characterized by:

2. The control device a non-tipping condition formula is stored in advance, the non-tipping condition formula including a first rotation moment acting on the tipping fulcrum of the main body due to gravity acting on a first center of gravity of the main body and the base, a second rotation moment acting on the tipping fulcrum of the main body due to gravity acting on a second center of gravity of the workpiece, the arm, and the hand, a third rotation moment acting on the tipping fulcrum of the main body due to vertical acceleration movement of the second center of gravity, and a fourth rotation moment acting on the tipping fulcrum of the main body due to horizontal acceleration movement of the second center of gravity; generating provisional motion data of the second center of gravity from the current position to the target position without considering tipping over of the main body, setting the horizontal acceleration of the second center of gravity related to the provisional motion data as provisional horizontal acceleration, setting the vertical acceleration of the second center of gravity related to the provisional motion data as provisional vertical acceleration, and if the provisional horizontal acceleration and the provisional vertical acceleration do not satisfy the non-tipping condition formula, correcting at least the provisional vertical acceleration to generate final motion data; 2. The robot system according to claim 1.

3. The control device if the non-overturning condition formula is satisfied when the horizontal acceleration of the second center of gravity is the provisional horizontal acceleration and the vertical acceleration of the second center of gravity is 0, the provisional horizontal acceleration is not corrected and the provisional vertical acceleration is corrected to a maximum value that satisfies the non-overturning condition formula, If the non-overturning condition formula is not satisfied when the horizontal acceleration of the second center of gravity is the provisional horizontal acceleration and the vertical acceleration of the second center of gravity is 0, the provisional horizontal acceleration is corrected to a maximum value that satisfies the non-overturning condition formula, and the provisional vertical acceleration is corrected to 0.

3. The robot system according to claim 2.

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