JP7690405B2 - Robot control device and robot control method - Google Patents

Description

This specification discloses a robot control device and a robot control method.

Conventionally, one robot control device proposed for this type is one that determines whether or not there is interference between the robot's motion path and surrounding objects placed around the robot (see, for example, Patent Document 1). This device approximates the components of the robot, such as the robot arm, and each surrounding object by modeling them as a rectangular parallelepiped or a combination of rectangular parallelepipeds, and determines whether or not there is overlap between the models projected onto a two-dimensional plane to determine whether or not there is interference.

JP 2019-025621 A

Here, it is conceivable to carry out the above-mentioned judgment process for all planned operation paths before the robot starts operating, and then operate the robot. However, the judgment process may take time, delaying the start of robot operation and affecting productivity. On the other hand, it is conceivable to carry out the judgment process while the robot is operating in order to reduce this effect, but appropriate measures are required to prevent the robot from colliding with surrounding objects if interference is determined to occur.

The primary objective of the present disclosure is to determine whether a robot will interfere with surrounding objects while the robot is operating, and to appropriately avoid collisions between the robot and surrounding objects if interference is determined to occur.

This disclosure takes the following measures to achieve the above-mentioned primary objective.

The robot control device according to the present disclosure includes:
A robot control device for controlling a robot,
A storage unit that stores information on surrounding objects arranged around the robot and information on components of the robot;
a determination processing unit that predicts an operating position of the robot from a current time point based on information related to an operation command of the robot while the robot is in operation, and performs interference determination between the constituent element and the peripheral object based on information about the constituent element and information about the peripheral object at the operating position;
a stop processing unit that stops operation of the robot at a deceleration greater than a preset deceleration when it is determined that interference occurs in the interference determination;
The gist of the invention is to provide the following:

The robot control device disclosed herein predicts the robot's operating position from the current time while the robot is operating, and performs an interference determination based on information on the components at that operating position and information on surrounding objects. If the interference determination determines that interference will occur, the robot's operation is stopped at a deceleration rate greater than a preset deceleration rate. This eliminates the need to perform an interference determination for the entire planned operation path before the robot starts operating, and makes it possible to prevent delays in starting the robot's operation. Furthermore, if interference is determined to occur, the robot's operation is stopped at a deceleration rate greater than a preset deceleration rate, making it possible to appropriately avoid collisions between the robot and surrounding objects.

FIG. 1 is a diagram showing an outline of the configuration of a robot system 10. FIG. 2 is a diagram showing an outline of the configuration of a robot 20. FIG. 2 is a block diagram showing electrical connections in the robot system 10. FIG. 4 is an explanatory diagram showing an example of interference determination information; FIG. 4 is an explanatory diagram showing an example of a set shape of an object surrounding the robot 20. FIG. 4 is an explanatory diagram showing an example of a set shape of a component of the robot 20. 11 is a flowchart showing an example of robot arm movement control. FIG. 4 is a diagram illustrating how a speed command value is derived. 11 is a flowchart showing an example of an interference determination process. FIG. 11 is an explanatory diagram showing an example of a vertex determination which is a first determination. FIG. 13 is an explanatory diagram showing an example of a line segment determination which is the second determination. FIG. 13 is an explanatory diagram showing an example of a line segment determination which is the second determination. FIG. 11 is an explanatory diagram showing an example of a projection determination which is a third determination. FIG. 11 is an explanatory diagram showing an example of changing a command value at the time of a forced stop.

Next, the form for implementing the invention of the present disclosure will be explained with reference to the drawings.

Figure 1 is a diagram showing an outline of the configuration of the robot system 10. Figure 2 is a diagram showing an outline of the configuration of the robot 20. Figure 3 is a block diagram showing the electrical connections of the robot system 10. Note that in Figures 1 and 2, the left-right direction is the X-axis direction, the front-back direction is the Y-axis direction, and the up-down direction is the Z-axis direction.

The robot system 10 uses a vertical articulated robot to perform a predetermined task on a workpiece. For example, the robot system 10 picks up a large number of loosely placed workpieces such as bolts B one by one and places them on a tray T in an upright position with the head facing down. As shown in FIG. 1, the robot system 10 includes a base 12, a cover 14, a bolt supply device 16, a tray transport device 18, a case 19, a robot 20, a control device 40 (see FIG. 3), and a management device 50 (see FIG. 3). The positions of the bolt supply device 16, the tray transport device 18, the case 19, and the robot 20 can be expressed in a world coordinate system based on the base 12.

The bolt supply device 16 is a belt conveyor device that transports a large number of loosely placed bolts B. The tray transport device 18 is a belt conveyor device that transports trays T in the X direction. The tray transport device 18 is installed in the center of the base 12 in the Y direction so as to extend in the X direction. The bolt supply device 16 is also installed in front of the tray transport device 18 on the base 12. The case 19 is used to supply workpieces and to discard workpieces with poor shapes. Note that multiple cases 19 may be arranged.

The robot 20 is a vertical articulated robot. The robot 20 is installed on the base 12 on the opposite side of the tray transport device 18 from the bolt supply device 16. The robot 20 includes a plurality of arms (tip arm 21, intermediate arms 22, 23, base arm 24) connected in series, a pedestal 25, an end effector 26, and a camera 28. The position of each arm can be expressed in a base coordinate system based on the bottom surface of the pedestal 25. Each arm includes a plurality of joints 31 to 35, motors 31a to 35a that drive each of the joints 31 to 35, and encoders 31b to 35b that detect the rotation angles of each of the joints 31 to 35. The base arm 24 is attached to the pedestal 25 via a joint 35 so as to be horizontally rotatable. The tip arm 21, the intermediate arms 22, 23, and the base arm 24 are connected to each other so as to be vertically rotatable via the corresponding joints 32 to 34. The distal arm 21 also has a disk-shaped flange 21f (hand) attached coaxially to the distal end in the longitudinal direction via a joint 31 that is rotatable about an axis along the longitudinal direction.

The end effector 26 includes a fixed part 26a that is fixed to the flange 21f of the distal arm 21 by a bolt or the like, and a tool part 26b that is supported on the fixed part 26a so that it can be opened, closed, rotated, etc. The tool part 26b is composed of an electromagnetic chuck, a mechanical chuck, a suction nozzle, etc., and is appropriately selected according to the shape and material of the workpiece (bolt B) to be worked on. The end effector 26 of this embodiment includes a motor, an encoder, etc. (not shown) so that the tool part 26b can be rotated vertically relative to the fixed part 26a. The position of the end effector 26 can be expressed in a tool (mechanical interface) coordinate system based on the end face of the flange 21f.

The camera 28 is attached to the side of the tip arm 21. The camera 28 takes an image of the workpiece (bolt B) supplied by the bolt supply device 16 and the workpiece in the case 19 to recognize its position and posture, and takes an image of the tray T to recognize the position of the tray T transported by the tray transport device 18. As shown in FIG. 2, mounting holes (female threaded holes) 21h are formed on the front and right sides of the tip arm 21, and similar mounting holes 21h are formed on the left and back sides (not shown). The camera 28 is attached to the mounting holes 21h formed on either side of the tip arm 21 using a bracket and bolt (not shown). That is, the camera 28 can be selectively attached to either the front side, left side, right side, or back side of the tip arm 21, and is attached to the right side in this embodiment.

The control device 40 is configured as a microprocessor with a CPU 41 at its core, and in addition to the CPU 41, it also includes a ROM 42, a HDD 43, a RAM 44, an input/output interface (not shown), and controls the operation of each device and the robot 20. The control device 40 receives detection signals from sensors (not shown) of the bolt supply device 16 and the tray transport device 18, detection signals from the encoders 31b to 35b of the robot 20, detection signals from the encoder of the end effector 26, images from the camera 28, and the like. The control device 40 also outputs control signals to the bolt supply device 16 and the tray transport device 18, drive signals to the motors 31a to 35a of the robot 20, drive signals to the tool portion 26b of the end effector 26, and a control signal to the camera 28.

The management device 50 is configured as a microprocessor with a CPU 51 at its core, and in addition to the CPU 51, is equipped with a ROM 52, HDD 53, RAM 54, an input/output interface (not shown), etc., and manages the entire system. The management device 50 receives inputs of the system's operating status, images captured by the camera 28, and input signals from the input device 56 from the control device 40. The input device 56 is an input device such as a keyboard or mouse through which the operator performs input operations. The management device 50 also outputs various instructions and information to the control device 40, and output signals to the output device 58. The output device 58 is a display device such as a liquid crystal display that displays various information.

Here, interference detection information is stored in the HDD 43 of the control device 40. FIG. 4 is an explanatory diagram showing an example of the interference detection information. FIG. 5 is an explanatory diagram showing an example of the set shape of an object in the vicinity of the robot 20. FIG. 6 is an explanatory diagram showing an example of the set shape of a component of the robot 20. In the interference detection information, coordinates (X, Y, Z) are set in either the world coordinate system, the base coordinate system, or the tool coordinate system, but since each coordinate system can be converted into the other, the following description will be made without making any particular distinction between them.

In the interference determination information 43a in FIG. 4A, information on the cover 14, the bolt supply device 16, the tray transport device 18, the tray T, and the case 19, which are peripheral objects of the robot 20, is stored. In this embodiment, an approximate shape (see FIG. 5) is set in which the shape of the peripheral objects based on 3D CAD data or the like is approximated by a rectangular parallelepiped, and of the eight vertices of each rectangular parallelepiped, the upper left corner is set as vertex P*1, and the lower right corner is set as vertex P*2. For example, in the case of the cover 14, the coordinates of the vertex P11 in the upper left corner and the vertex P12 in the lower right corner are stored as basic information. In addition, in the case of the tray T, the coordinates of the vertex P41 in the upper left corner and the vertex P42 in the lower right corner in a state where the tray T is transported to the work position by the tray transport device 18 are stored as basic information. In the case of the tray T, the coordinates of a rectangular parallelepiped approximated by adjusting the height of the work to its thickness may be stored. In addition, the tray T is transported to the work position or taken out by the tray transport device 18, so its presence or absence changes. For this reason, in the interference determination information 43a, additional information about the tray T is stored to the effect that the tray T can be set as an excluded tray.

In the interference determination information 43b in FIG. 4B, information on the end effector 26, the camera 28, and the intermediate arms 1 and 2 (intermediate arms 22 and 23), which are components of the robot 20, is stored. In this embodiment, an approximate shape is set in which the shapes of the end effector 26 and the camera 28 based on 3D CAD data or the like are approximated by a rectangular parallelepiped. The end effector 26 is approximated by a shape obtained by combining rectangular parallelepipeds, with the fixed part 26a and the tool part 26b being each approximated by a rectangular parallelepiped. As with the surrounding objects, the coordinates of the upper left corner vertex P*1 and the lower right corner vertex P*2 of the eight vertices of each rectangular parallelepiped are stored as basic information for these components. The coordinates of the upper left corner vertex P71 and the lower right corner vertex P72 of the tool part 26b in the initial state (see FIG. 6A) in which the tip faces downward are stored. In addition, the offset amount of the vertically rotated rotation state (see FIG. 6B) is stored as additional information for the tool part 26b. The offset amount is stored as an offset amount ΔP71 for the apex P71 at the upper left corner and an offset amount ΔP72 for the apex P72 at the lower right corner. The coordinates of the apex P81 at the upper left corner and the apex P82 at the lower right corner of the rectangular parallelepiped are stored as basic information for the camera 28 when the camera 28 is attached to the front side of the distal arm 21 (see FIG. 6A). In addition, the offset amount when the camera 28 is attached to the left side, right side, and rear side is stored as additional information for the camera 28. In this embodiment, since the camera 28 is attached to the right side of the distal arm 21 (see FIG. 6B), the offset amount of the right side, i.e., the offset amount ΔP81R of the apex P81 at the upper left corner and the offset amount ΔP82R of the apex P82 at the lower right corner are used.

In the interference determination information 43b, the length L1 of each line segment and the offset amount ΔL11 to ΔL14 from the arm center 22c are stored as basic information for the four line segments A11 to A14 that approximate the four corners along the longitudinal direction of the intermediate arm 1 (intermediate arm 22). In addition, in the interference determination information 43b, the length L2 of each line segment and the offset amount Δ21, Δ22 from the arm center 23c are stored as basic information for the two front line segments A21 and A22 that approximate the four corners along the longitudinal direction of the intermediate arm 2 (intermediate arm 23). The two rear line segments of the intermediate arm 2 (intermediate arm 23) are excluded because there is little need for interference determination. Note that each offset amount can be stored as a value in the XYZ direction, but the offset amount can be omitted for directions without offset.

The following is an explanation of the operation of the robot 20. The control device 40 executes processes to cause the robot 20 to pick up a workpiece and place the workpiece on the tray T, but here we will explain the movement control of the robot arm when executing these processes. Figure 7 is a flowchart showing an example of the robot arm movement control.

In the robot arm movement control, the CPU 41 of the control device 40 first operates each arm of the robot 20 using a speed command value obtained by moving average processing of a rectangular wave speed command (S100). FIG. 8 is an explanatory diagram of how the speed command value is derived. The CPU 41 obtains the movement distance of the tip of the distal arm 21 from the current position and posture to the target position and posture, divides this movement distance by the target speed V1 to calculate time T1, and derives a rectangular wave speed command with a constant speed for each control cycle (FIG. 8A). Next, the CPU 41 derives a trapezoidal speed command having an acceleration section, a constant speed section, and a deceleration section by moving average processing of the rectangular wave speed using a moving average filter (FIG. 8B). In S100, the CPU 41 sets target positions for each of the joints 31 to 35 of each arm so that the tip of the distal arm 21 moves based on the speed command value for each control period in this trapezoidal speed command, and drives and controls each of the motors 31 a to 35 a so that the positions of each of the joints 31 to 35 coincide with the target positions.

Next, the CPU 41 performs interference determination processing while the robot 20 is in operation (S110), and determines whether there is a risk of interference between components of the robot 20 and surrounding objects (S120). If the CPU 41 determines that there is no interference, it determines whether the robot 20 has passed through a deceleration section and come to a normal stop (S130), and if it determines that the robot has not come to a normal stop, it returns to S100 and performs processing. That is, the CPU 41 operates each arm of the robot 20 based on the speed command value for the next control cycle. The control cycle is, for example, several hundred μsec. Furthermore, if the CPU 41 determines that the robot has come to a normal stop in S130, it ends the robot arm movement control.

The interference determination process during operation of S110 is executed based on the flowchart of FIG. 9. In the interference determination process, the CPU 41 determines whether the mounting position of the camera 28 has been set (S200), and if it is determined that it has not been set, determines whether it is the mounting position on the front side (S210). When the worker mounts the camera 28 or changes the mounting position, the worker inputs to the management device 50 whether the mounting position is the front side, left side, right side, or back side using the input device 56. The CPU 41 makes the determination of S210 based on the mounting position information transmitted from the management device 50. If the CPU 41 determines that it is the front side, it sets the coordinates of the vertices P81 and P82, which are basic information of the camera 28 in the interference determination information 43b, as the determination target (S220). Furthermore, if the CPU 41 determines that the camera 28 is not on the front side, it selects the offset amount corresponding to the mounting position from the additional information of the camera 28 in the collision determination information 43b, reflects the offset amount in the coordinates of the vertices P81 and P82, and sets them as the determination target (S230). After performing the settings of S220 and S230, the CPU 41 determines that the setting has been completed in S200 unless the mounting position of the camera 28 has been changed, and skips S210 to S230.

Next, the CPU 41 determines whether or not a tray T is present at the work position on the tray transport device 18 based on a detection signal from a sensor of the tray transport device 18 (S240). If the CPU 41 determines that a tray T is present, it sets the tray T as the subject of this determination (S250), and if it determines that the tray T is not present, it excludes the tray T from the subject of this determination (S260). In this way, the CPU 41 dynamically changes whether or not to set the tray T as the subject of the interference determination depending on the presence or absence of a tray T on the tray transport device 18.

Next, the CPU 41 determines whether the tool part 26b of the end effector 26 is in the initial state (S270). When the CPU 41 determines that the tool part 26b is in the initial state, it sets the coordinates of the vertices P71 and P72, which are the basic information of the tool part 26b in the interference determination information 43b, as the current determination target (S280). When the CPU 41 determines that the tool part 26b is not in the initial state but in a rotating state, it selects the rotation offset amount, which is the additional information of the tool part 26b in the interference determination information 43b, and reflects the offset amount in the coordinates of the vertices P71 and P72 and sets them as the current determination target (S290). In this way, the CPU 41 dynamically changes whether the initial state or the rotating state is to be determined according to the state of the tool part 26b. Note that the CPU 41 may read out the offset amount only when the tool part 26b is in a rotating state and reflect it in the basic information.

After performing various settings for interference determination in this way, the CPU 41 predicts the operating position of the robot 20 (the hand position of the distal arm 21) after the current time point using the rectangular wave speed command before moving average processing (S300). As described above, since the robot 20 operates based on a command value based on a trapezoidal speed command, for example, the command value v01 at time t01 (first control cycle) in FIG. 8B is smaller than the target speed V1 before moving average processing. Therefore, considering the moving distance, which is the product of time and speed, the position predicted using the rectangular wave speed command is a position that is a distance of the area difference (shaded area in FIG. 8B) ahead of the position instructed to move in the current control cycle. That is, the CPU 41 predicts a position that is ahead of the arrival position based on the command value of the current control cycle. The CPU 41 sets the vertex coordinates and line segment coordinates of each component to be determined from the predicted operating position (S310).

Then, the CPU 41 performs the interference judgment by the following first to third judgments. The first judgment is a judgment based on the information of the vertices of the components and the surrounding objects (vertex judgment). FIG. 10 shows an example of the vertex judgment, which is the first judgment. As shown in FIG. 10, in the first judgment, the presence or absence of interference is judged based on whether or not the vertex of the judgment target, which is the component, is located in the space of a rectangular parallelepiped defined by the upper left vertex P*1 and the lower right vertex P*2 of the surrounding objects. For example, the CPU 41 judges that there is no interference if the vertex of the component is located in the space of the vertices P11 and P12 of the cover 14, and judges that there is interference if the vertex of the component is not located in the space of the vertices P11 and P12. Also, the CPU 41 judges that there is interference if the vertex of the component is located in the space of the vertices P31 and P32 of the tray transport device 18, and judges that there is no interference if the vertex of the component is not located in the space of the vertices P31 and P32.

The second judgment is a judgment (line judgment) based on information on the line segments of the components of the robot 20 and the surfaces of the surrounding objects. An example of the line judgment, which is the second judgment, is shown in Figures 11 and 12. As shown in Figure 11, in the second judgment, the presence or absence of interference is judged based on whether or not the line segments of the components of the robot 20 intersect with each surface of a rectangular parallelepiped defined by the upper left vertex P*1 and the lower right vertex P*2 of the surrounding objects. First, the CPU 41 derives the start point coordinates Ps and the end point coordinates Pe for each of the line segments A11 to A14, A21, and A22 of the arm, which are the components of the robot 20, by kinematic calculation. That is, the CPU 41 determines the start point coordinates and the end point coordinates of the arm centers 22c and 23c according to the hand position of the tip arm 21 by kinematic calculation, and derives the start point coordinates Ps and the end point coordinates Pe of each line segment based on those coordinates and the length and offset amount of the line segment stored in the interference judgment information 43b. Next, the CPU 41 determines the possibility of intersection between any plane PS of the surrounding object and the line segment. That is, the CPU 41 determines a normal vector NV at a point P0 on the plane PS, and vectors Vs and Ve extending from the point P0 to the starting coordinate Ps and the ending coordinate Pe, and compares the positive and negative signs of the inner product of the vectors Vs and Ve with the normal vector NV. For example, one side (upper side in FIG. 12) of the plane PS is positive, and the other side (lower side in FIG. 12) of the plane PS is negative. If the positive and negative signs are the same, the CPU 41 determines that there is no possibility of intersection because the starting coordinate Ps and the ending coordinate Pe are on the same side of the plane PS (see FIG. 12A), and if the positive and negative signs are different, the starting coordinate Ps and the ending coordinate Pe are on different sides of the plane PS, so there is a possibility of intersection (see FIG. 12B). When the CPU 41 determines that there is a possibility of intersection, it calculates the coordinates of the intersection between the line segment and the plane PS, and determines that there will be interference if the calculated coordinates of the intersection are included in the surrounding objects, and determines that there will be no interference if the coordinates of the intersection are not included in the surrounding objects.

The third judgment is a judgment based on a projected image of the components and the surrounding objects projected onto a predetermined projection surface, such as the top surface of the base 12 (projection judgment). FIG. 13 shows an example of the projection judgment, which is the third judgment. FIG. 13 illustrates an example in which the components are projected as a projected image J and the surrounding objects are projected as a projected image K, and the XY direction is determined along the edge of the projected image K. First, the CPU 41 calculates the center-to-center distance Dx in the X direction between the projected images J and K, the distance Jx from the center of the projected image J to the edge in the X direction, and the distance Kx from the center of the projected image K to the edge in the X direction, and compares the sum of the distances Jx and Kx with the center-to-center distance Dx. If the center-to-center distance Dx is greater than the sum of the distances Jx and Kx, the CPU 41 judges that there is no overlap of the projected images J and K in the X direction, and if the center-to-center distance Dx is equal to or less than the sum of the distances Jx and Kx, it judges that there is overlap of the projected images J and K in the X direction. The CPU 41 also calculates the center-to-center distance Dy (not shown) between the projected images J and K in the Y direction, the distance Jy from the center of the projected image J to the edge in the Y direction, and the distance Ky from the center of the projected image K to the edge in the Y direction, and compares the sum of the distances Jy and Ky with the center-to-center distance Dy to determine whether or not the projected images J and K overlap in the Y direction. The CPU 41 performs a similar determination in two directions defined along the side of the projected image J, and determines whether or not there is overlap in a total of four directions. The CPU 41 determines that there is no interference if there is no overlap in even one direction, such as the X direction in FIG. 13, and determines that there is interference if there is overlap in all directions.

The CPU 41 performs an interference determination between each component of the robot 20 and the cover 14 based on the first and second of these first to third determinations (S320). The CPU 41 also performs an interference determination between each component of the robot 20 and each surrounding object other than the cover 14 based on the second and third determinations (S330), and ends the interference determination process. In this embodiment, the processing load of the interference determination is reduced by using an approximate shape, and the time required for the interference determination process is set to several tens of μsec, which fits within the control period, to prevent it from affecting the operation control.

If there is a risk of interference as a result of such interference determination processing, the CPU 41 determines that interference will occur in S120 of the robot arm movement control in FIG. 7, and forcibly stops the arm of the robot 20 by increasing the deceleration rate from normal (S140). FIG. 14 shows a case where interference is determined to occur at time tn as an example of changing the command value at the time of forced stop. In this case, the robot 20 is controlled to stop at a speed (solid line in the figure) with a greater deceleration rate than the normal speed (dotted line in the figure) in the deceleration section set by the moving average processing. In FIG. 14, the position of time tn in the speed command of the rectangular wave corresponds to the end point position in the speed command of the trapezoidal wave, and by increasing the deceleration rate, the arm of the robot 20 is stopped before the end point position. In this way, when interference is determined to occur in the interference determination during the operation of the robot 20, the robot 20 (arm) can be appropriately stopped to prevent collision with surrounding objects. Then, the CPU 41 notifies a forced stop error (S150) and ends the robot arm movement control. The CPU 41 notifies the management device 50 that an error has occurred, and upon receiving the notification, the management device 50 displays the occurrence of an error on the output device 58, outputs an error sound from a speaker (not shown), or turns on a warning light (not shown).

Here, the correspondence between the components of this embodiment and the components of this disclosure will be clarified. The control device 40 of this embodiment corresponds to the robot control device of this disclosure, the HDD 43 corresponds to the storage unit, the CPU 41 that executes S110 of the robot arm movement control in FIG. 7 (interference determination process in FIG. 9) corresponds to the determination processing unit, and the CPU 41 that executes S140 of the robot arm movement control corresponds to the stop processing unit. Note that in this embodiment, an example of the robot control method of the present disclosure is also clarified by explaining the operation of the control device 40.

The control device 40 of the present embodiment described above performs interference determination based on information on components at the predicted position during operation of the robot 20 and information on surrounding objects, and stops operation of the robot 20 with a large deceleration if it determines that interference will occur. This eliminates the need for the control device 40 to perform interference determination for the entire planned operation path before the robot 20 starts operating, and can prevent delays in starting operation of the robot 20. Furthermore, the control device 40 can appropriately avoid collisions between the robot 20 and surrounding objects.

In addition, the control device 40 performs a composite interference determination using two of the first to third determinations, thereby suppressing erroneous determinations and enabling accurate interference determination. In addition, the control device 40 uses approximate shapes that approximate the surrounding objects and components using rectangular parallelepipeds or combinations of rectangular parallelepipeds, thereby suppressing an increase in the processing load for interference determination and preventing it from affecting the operation control of the robot 20.

In addition, the control device 40 stores multiple pieces of information on different positions (initial state, rotation state) for the tool part 26b (the same component) in the HDD 43, so that interference determination can be performed appropriately even if the state of the tool part 26b changes. In addition, the control device 40 excludes the tray T from the determination target depending on the presence or absence of the tray T, for example, so that interference determination can be performed appropriately even if the presence or absence of the tray T changes during the operation of the robot 20.

It goes without saying that the present disclosure is in no way limited to the above-described embodiments, and may be implemented in various forms as long as they fall within the technical scope of the present disclosure.

For example, in the above-described embodiment, information on surrounding objects selected depending on the presence or absence of surrounding objects such as a tray T is used, but this is not limited thereto, and the same information on the surrounding objects may be used regardless of the presence or absence of the surrounding objects. Alternatively, information on each position of surrounding objects whose position can change may be stored in the interference determination information 43a, and information selected depending on the position of the surrounding objects at the time of determination may be used. For example, information selected depending on whether the tray T is in the loading position at one end of the conveyor, the working position in the center, or the unloading position at the other end of the conveyor may be used.

In the above-described embodiment, for example, multiple pieces of information with different positions related to tool part 26b are stored in HDD 43, but this is not limited to this. For example, multiple pieces of information (multiple pieces of information with different forms related to the same type of component) for each detachable tool part such as an electromagnetic chuck, mechanical chuck, or suction nozzle may be stored. Then, information corresponding to the currently attached tool part may be selected to perform interference determination. Alternatively, the same information may be used regardless of changes in the components of robot 20, and for example, information common to multiple tool parts may be stored in HDD 43.

In the above-described embodiment, information on approximate shapes of components and surrounding objects approximated by a rectangular parallelepiped or a combination of rectangular parallelepipeds is stored in HDD 43, but information on approximations by other shapes such as a sphere or a combination of these various shapes may also be stored. Alternatively, the storage is not limited to storing information on approximate shapes, and actual shape information such as 3D CAD data may also be stored. However, in order to reduce the processing load of interference detection, it is preferable to store information on approximate shapes.

In the above-described embodiment, the interference determination is performed by combining any two of the first to third determinations, but this is not limited to this, and the interference determination may be performed by a combination of three determinations. Furthermore, the interference determination may be performed by combining any two or more of a plurality of determinations, including other determinations, without being limited to the first to third determinations.

In the above-described embodiment, the position is predicted based on the speed command of the square wave before moving average processing is performed to perform the interference judgment, but the present invention is not limited to this and it is sufficient that the interference judgment is performed at a position after the current time (future position). Here, the position after the current time may be a position that takes into account the braking distance required to avoid interference when it is determined that interference will occur in the interference judgment. Note that although the command value is set by moving average processing, the command value may be set by other processing.

In the above-described embodiment, the present disclosure has been exemplified as being applied to a vertical articulated robot, but is not limited to this and may be applied to any robot that may interfere with surrounding objects, such as a horizontal articulated robot or a parallel link robot.

Here, the robot control device of the present disclosure may be configured as follows. For example, in the robot control device of the present disclosure, the judgment processing unit may perform the interference judgment using at least two of a first judgment based on information on the vertices of the components and the peripheral object, a second judgment based on information on the contour lines of the components and information on the surfaces of the peripheral object, and a third judgment based on information on projected images of the components and the peripheral object projected onto a predetermined projection surface. In this way, interference judgment during operation of the robot is performed in a composite manner using at least two judgments, thereby suppressing erroneous judgments and making judgments with high accuracy.

In the robot control device of the present disclosure, the storage unit may store information regarding the approximate shapes of the surrounding objects and the components, each of which is approximated to either a rectangular parallelepiped or a combination of rectangular parallelepipeds. This can prevent an increase in the processing load of interference detection, making it possible to perform interference detection during robot operation without affecting operation control.

In the robot control device disclosed herein, the storage unit may store multiple pieces of information on different positions of the same component and multiple pieces of information on different forms of the same type of component, and the determination processing unit may select the information on the component that corresponds to the current configuration of the robot and perform the interference determination based on the selected information. In this way, even if the components of the robot change, the interference determination can be performed appropriately by changing the selected information.

In the robot control device of the present disclosure, the storage unit may store information about the surrounding objects whose presence or absence or position changes during operation of the robot, and the determination processing unit may select information about the surrounding objects depending on the presence or absence or change in the position of the surrounding objects, and perform the interference determination based on the selected information. In this way, even if the presence or absence or position of the surrounding objects changes during operation of the robot, interference determination can be appropriately performed by changing the selected information.

The robot control method disclosed herein is a robot control method for controlling a robot, and includes the steps of: (a) predicting an operating position of the robot from a current time point based on information related to an operation command for the robot while the robot is in operation, and determining whether the component will interfere with the surrounding object based on information about the component and information about the surrounding object at the operating position; and (b) stopping the operation of the robot at a deceleration greater than a preset deceleration if it is determined in step (a) that there will be interference.

As with the robot control device described above, the robot control method disclosed herein does not require interference determination for the entire planned operation path before the robot starts operating, and can prevent delays in starting the robot's operation. Furthermore, if interference is determined to occur, the robot's operation is stopped at a deceleration greater than a pre-set deceleration, thereby appropriately avoiding collisions between the robot and surrounding objects. Note that in this robot control method, various aspects of the robot control device described above may be employed, and steps may be added that realize each function of the robot control device described above.

This disclosure can be used in the robot manufacturing industry, etc.

10 robot system, 12 base, 14 cover, 16 bolt supply device, 18 tray transport device, 19 case, 20 robot, 21 tip arm, 21f flange, 21h mounting hole, 22, 23 intermediate arm, 24 base arm, 25 base, 26 end effector, 26a fixed portion, 26b tool portion, 28 camera, 31-34 joints, 31a-35a motors, 31b-35b encoders, 40 control device, 41, 51 CPU, 42, 52 ROM, 43, 53 HDD, 43a, 43b interference determination information, 44, 54 RAM, 50 management device, 56 input device, 58 output device, B bolt, T tray.

Claims (8)

A robot control device for controlling a robot,
A storage unit that stores information on surrounding objects arranged around the robot and information on components of the robot;
a determination processing unit that predicts an operating position of each joint of each arm of the robot after the current time based on information regarding an operation command for a hand of the tip arm of the robot from a current position and posture to a target position and posture during operation of the robot, and when the operating position is a position taking into consideration at least a braking distance of the robot, performs interference determination between the component and the peripheral object based on information regarding the component and information regarding the peripheral object at the operating position;
a stop processing unit that stops operation of the robot at a deceleration greater than a preset deceleration when it is determined that interference is predicted in the interference determination;
A robot control device comprising: The robot control device according to claim 1 ,
The robot control device, wherein the judgment processing unit performs the interference judgment using at least two of a first judgment based on information on vertices of the component and the peripheral object, a second judgment based on information on the contour line of the component and information on the surfaces of the peripheral object, and a third judgment based on information on projected images of the component and the peripheral object projected onto a predetermined projection surface. The robot control device according to claim 1 or 2,
The storage unit stores information regarding approximate shapes of the peripheral object and the component that are approximated to either a rectangular parallelepiped or a combination of rectangular parallelepipeds. The robot control device according to any one of claims 1 to 3,
the storage unit is capable of storing a plurality of pieces of information on the same component but with different positions and a plurality of pieces of information on the same type of component but with different forms,
The robot control device, wherein the determination processing unit selects information of the component corresponding to a current configuration of the robot, and performs the interference determination based on the selected information. The robot control device according to any one of claims 1 to 4,
The memory unit is capable of storing information on the surrounding objects whose presence or position changes during operation of the robot,
The determination processing unit selects information about the peripheral object depending on the presence or absence of the peripheral object or a change in a position of the peripheral object, and performs the interference determination based on the selected information. A robot control device for controlling a robot,
A storage unit that stores information on surrounding objects arranged around the robot and information on components of the robot;
a determination processing unit that predicts an operating position of each joint of each arm of the robot after the current time based on information regarding an operation command for a hand of the tip arm of the robot from a current position and posture to a target position and posture during operation of the robot, and when the operating position is a position taking into consideration at least a braking distance of the robot, performs interference determination between the component and the peripheral object based on information regarding the component and information regarding the peripheral object at the operating position;
a stop processing unit that stops operation of the robot at a deceleration greater than a deceleration that is preset for a drive unit that drives the robot when it is determined that interference occurs in the interference determination;
A robot control device comprising: A robot control device for controlling a robot,
a storage unit that stores information on surrounding objects arranged around the robot, information on components of the robot, and additional information on changes in state of the components accompanying the operation of the robot;
a determination processing unit that predicts an operating position of each joint of each arm of the robot after the current time based on information regarding an operation command for the tip of the robot's distal arm from a current position and posture to a target position and posture during operation of the robot, and when the operating position is a position taking into consideration at least the braking distance of the robot, performs interference determination between the component and the peripheral object based on information regarding the component at the operating position, additional information regarding a change in state of the component, and information regarding the peripheral object;
a stop processing unit that stops operation of the robot at a deceleration greater than a preset deceleration when it is determined that interference occurs in the interference determination;
A robot control device comprising: A robot control method for controlling a robot, comprising:
(a) predicting an operating position of each joint of each arm of the robot after the current time based on information regarding an operation command for the tip of the robot's end arm from a current position and posture to a target position and posture during operation of the robot, and when the operating position is a position taking into consideration at least the braking distance of the robot, determining interference between the components of the robot and the peripheral objects based on information regarding the components of the robot at the operating position and information regarding the peripheral objects disposed around the robot;
(b) stopping the operation of the robot at a deceleration greater than a preset deceleration when it is determined in the step (a) that interference is predicted;
A robot control method comprising:

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