JP2023135808A - Route generation method for robot system and control method of robot system - Google Patents

Abstract

To avoid operation stopping of a robot because the number of operation commands is insufficient.SOLUTION: A route generation method includes: a step of storing in a storing part operation commands to designate target positions of a robot received from an external instrument; a step in which when the number of operation commands stored in the storing part is a first threshold Th1 or more, a first interpolation process using Th1-operation commands is executed to interpolate a route including a space between a target position designated at least by the first operation command and a target position designated by the next operation command, of the Th1-operation commands; and a step in which when the number of operation commands stored in the storing part is a second threshold Th2 or more that is smaller than the first threshold Th1 and is less than the first threshold Th1, a second interpolation process using Th2-operation commands is executed to interpolate a route between the target position designated by the first operation command and the target position designated by the next operation command, of the Th2-operation commands.SELECTED DRAWING: Figure 3

Description

The present disclosure relates to a route generation method for a robot system and a method for controlling the robot system.

Patent Document 1 discloses that in order to remotely control a robot system, an external computer generates a motion command, and transmits the motion command including information indicating the target position of a predetermined part of the robot to the robot system via communication. It is stated that the files should be output sequentially.

As in the technology described in Patent Document 1, when a remote computer sends an operation command indicating the target position of a determined part of the robot, the robot controller of the robot system A trajectory is generated by interpolating paths between multiple target positions based on information indicating the target position, and the robot is operated along the generated trajectory.

For highly accurate interpolation processing, it is necessary to use multiple motion commands. For this reason, the robot system generally buffers motion commands received from an external computer and performs interpolation processing using the buffered motion commands. For example, each time a robot system reaches a specified target position, it reads out a predetermined number of target position data from a buffer and performs interpolation processing on data for target positions beyond the current position.

Japanese Patent Application Publication No. 2021-154444

If the robot system is unable to receive movement commands due to communication failure, the number of buffered movement commands may be insufficient for the number required for interpolation processing at the timing when interpolation processing is executed. There are things to do. In such a case, the robot system could not perform interpolation processing, so the robot could not continue operating.

According to one aspect of the present disclosure, a route generation method for a robot system is provided. This route generation method for a robot system includes a receiving step of receiving a motion command specifying a target position of the robot from an external device and storing the motion command in a storage section; When the number of the plurality of operation commands specifying the target position further ahead and in which the order of execution of the operation commands is consecutive is greater than or equal to the first threshold Th1, By executing the first interpolation process using the movement commands, the target position specified by at least the first movement command among the Th1 movement commands and the target position specified by the next movement command are determined. a first interpolation step of interpolating a route including a route between the target position and the target position; and a first interpolation step that specifies the target position beyond the current position stored in the storage unit, the operation command being executed. If the number of the plurality of operation commands whose order of execution is consecutive is greater than or equal to a second threshold Th2 smaller than the first threshold Th1, and less than the first threshold Th1, Th2 of the operation commands are By executing the used second interpolation process, the difference between the target position specified by the first movement command and the target position specified by the next movement command among the Th2 movement commands is determined. a second interpolation step of interpolating a path between the two.

According to another aspect of the present disclosure, a method of controlling a robot system is provided. This robot system control method includes a receiving step of receiving a motion command specifying a target position of the robot from an external device and storing the motion command in a storage section; When the number of the plurality of motion commands specifying the previous target position and in which the order of execution of the motion commands is consecutive is greater than or equal to the first threshold Th1, By executing the first interpolation process using the movement commands, the target position specified by at least the first movement command and the target position specified by the next movement command among the Th1 movement commands are determined. a first interpolation step for interpolating a route including a path to and from a target position; and the operation command, which is stored in the storage unit and specifies the target position beyond the current position, and the operation command is executed. If the number of the plurality of operation commands whose order is consecutive is equal to or greater than a second threshold Th2 smaller than the first threshold Th1, and less than the first threshold Th1, Th2 of the operation commands are used. By executing the second interpolation process, the distance between the target position specified by the first movement command and the target position specified by the next movement command among the Th2 movement commands is determined. a second interpolation step of interpolating the path of the robot; and an operation step of operating the robot along the interpolated path.

1 is a schematic diagram showing the overall configuration of a robot system. FIG. 2 is a block diagram showing the functional configuration of a robot controller. FIG. 3 is a diagram for explaining a method of interpolating a route between target points. FIG. 7 is a diagram for explaining another method of interpolating a route between target points. 7 is a flowchart of interpolation route generation processing. FIG. 7 is a diagram for explaining an interpolation method in another embodiment 1. FIG.

A1. Embodiment:
FIG. 1 is a schematic diagram showing the overall configuration of a robot system 10 according to this embodiment. The robot system 10 includes a robot 100 and a robot controller 200.

The robot 100 includes six joints J1 to J6. The robot 100 places the end effector 80 attached to the tip of the arm 50 at a specified position in a three-dimensional space in a specified posture by rotating or moving straight joints J1 to J6 using servo motors. can do. The robot 100 includes an arm 50, a servo motor 60, an angle sensor 65, a reduction gear 70, an end effector 80, a force sensor 85, and a base 90.

Arm 50 includes six joints J1 to J6. Joints J1 to J6 are rotational joints. Arm 50 also includes arm elements 54, 55, 56, 57, 58, 59. Each of the joints J1 to J5 is equipped with a servo motor 60, an angle sensor 65, and a speed reducer 70. In FIG. 1, the servo motor 60, the angle sensor 65, and the speed reducer 70 are illustrated only at the joint J1 to facilitate understanding of the technology.

The arm element 54 is supported at one end by a speed reducer 70. The connecting portion between the arm element 54 and the reducer 70 constitutes a joint J1. Joint J1 is a torsion joint. Arm element 55 is connected to arm element 54 at one end. A connecting portion between arm element 55 and arm element 54 constitutes a joint J2. Joint J2 is a bending joint. Arm element 56 is connected to arm element 55 at one end. The connecting portion between arm element 56 and arm element 55 constitutes joint J3. Joint J3 is a bending joint.

Arm element 57 is connected to arm element 56 at one end. The connecting portion between arm element 57 and arm element 56 constitutes joint J4. Joint J4 is a torsion joint. Arm element 58 is connected to arm element 57 at one end. The connecting portion between arm element 58 and arm element 57 constitutes joint J5. Joint J5 is a bending joint. Arm element 59 is connected to arm element 58 at one end. The connecting portion between arm element 59 and arm element 58 constitutes joint J6. Joint J6 is a torsion joint. An end effector 80 is attached to the other end of the arm element 59 via a force sensor 85.

The servo motor 60 is supplied with current from the robot controller 200 to rotate the output shaft 60o in order to drive the joint J1. An output shaft 60o of the servo motor 60 is connected to an input shaft 70i of the reducer 70. The servo motors 60 provided in each of the joints J2 to J6 similarly drive the corresponding joints.

The angle sensor 65 detects the angular position of the output shaft 60o of the servo motor 60 as the rotation angle of the joint J1, and outputs the detected value to the robot controller 200. Angle sensor 65 is a rotary encoder. The angle sensors 65 provided in each of the joints J2 to J6 similarly detect the rotation angle of the corresponding joint.

The speed reducer 70 converts the rotational input to the input shaft 70i into a rotational output having a lower rotational speed than the rotational input, and outputs the rotational output from the output shaft. An arm element 54 is fixed to the output shaft of the speed reducer 70. Note that in FIG. 1, illustration of the output shaft of the reduction gear 70 is omitted. Rotation of the output shaft 60o of the servo motor 60 is transmitted to the arm element 54 constituting the joint J1 via the reduction gear 70. As a result, joint J1 is rotated. The arm element 54 is moved by rotation of the joint J1. The reducers 70 provided in each of the joints J2 to J6 also function to transmit the rotational output of the corresponding servo motor 60 to the connected arm element.

In the robot 100, each of the joints J1 to J6 is rotatable. Rotation of each joint changes the relative angle of the two arm elements connected via the joint. Therefore, the end effector 80 attached to the arm element 59 can be placed at any position and in any orientation.

The end effector 80 is attached to the arm element 59 via a force sensor 85. The end effector 80 is, for example, a device for gripping a workpiece (not shown). To facilitate understanding of the technology, the end effector 80 is shown as a cylindrical member in FIG. 1 . The control point of the robot 100 is set, for example, at a position on the rotation axis of the arm element 59 and at a predetermined distance from the arm element 59. The control point is a point representing the position of the end effector 80 in three-dimensional space. A control point is sometimes called a TCP (Tool Center Point). In the embodiment, the robot controller 200 controls the position of a control point in the robot coordinate system RC by driving the robot 100.

Force sensor 85 is attached to arm element 59. The force sensor 85 detects the magnitude of force acting on the end effector 80 parallel to the detection axes of the X, Y, and Z axes and the magnitude of torque around each detection axis in a sensor coordinate system different from the robot coordinate system. and outputs the detected value to the robot controller 200. The sensor coordinate system is a three-dimensional orthogonal coordinate system with the point on the force sensor 85 as the origin. Note that the robot controller 200 has correspondence data that associates the sensor coordinate system with the robot coordinate system, and can convert the coordinate values of the sensor coordinate system into the coordinate values of the robot coordinate system.

The base 90 supports members that make up the robot 100. By fixing the base 90 to the floor, the robot 100 is installed on the floor.

Robot controller 200 controls robot 100 and end effector 80 according to operation commands received from control device 500. The robot controller 200 is communicably connected to the robot 100. Further, the robot controller 200 is communicably connected to the control device 500. The control device 500 is also referred to as an external device.

In the embodiment, a coordinate system that defines a space in which the robot 100 is installed with reference to the position of the base 90 is referred to as a robot coordinate system RC. The robot coordinate system RC is a three-dimensional orthogonal coordinate system defined on a horizontal plane by an X-axis and a Y-axis that are orthogonal to each other, and a Z-axis whose positive direction is vertically upward. Hereinafter, the X axis in the robot coordinate system RC will be simply referred to as the X axis. The Y-axis in the robot coordinate system RC is simply referred to as the Y-axis. The Z axis in the robot coordinate system RC is simply referred to as the Z axis. The position in the robot coordinate system RC can be specified by the position in the X-axis direction, the position in the Y-axis direction, and the position in the Z-axis direction. Further, an arbitrary posture in the robot coordinate system RC can be expressed by the angular position RX of rotation around the X axis, the angular position RY of rotation around the Y axis, and the angular position RZ of rotation around the Z axis. Hereinafter, when the term "position" is used, it means not only position in a narrow sense but also posture.

Further, the robot controller 200 can perform PTP control (Point To Point control) and CP control (Continuous Path control) regarding control of control points of the robot 100. PTP control is control in which only the target position and orientation are specified, and the movement path to reach the target position is not specified. CP control is control in which the position and orientation are specified along the motion path. In the embodiment, the robot 100 is controlled by CP control.

FIG. 2 is a block diagram showing the functional configuration of the robot controller 200. The robot controller 200 includes a memory 201 and a CPU (Central Processing Unit) 202. The memory 201 stores programs and data used for various processes executed by the robot controller 200. Furthermore, the memory 201 is used as a work memory for the CPU 202. That is, the memory 201 functions as a storage section. The CPU 202 implements various functions by executing programs stored in the memory 201.

Functionally, the robot controller 200 includes a position calculation section 210, a command output section 220, and an operation control section 230. The functions of the position calculation section 210, command output section 220, and operation control section 230 are realized by the CPU 202.

The position calculation unit 210 calculates the position of the control point and outputs a value indicating the determined position of the control point to the command output unit 220. The memory 201 of the robot controller 200 stores in advance position correspondence data that associates the combinations of rotation angles of the servo motors 60 that drive the joints J1 to J6 with the positions of control points in the robot coordinate system. . The position calculation unit 210 calculates the robot coordinates of the control point at predetermined time intervals based on the position correspondence data and the detected values of the angle sensors 65 corresponding to the servo motors 60 that drive the joints J1 to J6. Calculate the coordinates indicating the position of the control point in the system RC. The position calculation unit 210 outputs the coordinate values indicating the determined position of the control point to the command output unit 220.

The command output unit 220 receives an operation command including a coordinate value indicating a target point of a control point and a cycle from the control device 500. The period is a value that specifies the time for transitioning the control point to the target point.

In the operation command, a target point indicating a target position to which a control point is to be moved is specified in one cycle, but a route to the target point is not specified. Therefore, the command output unit 220 interpolates a route between target points specified by two or more consecutive operation commands.

For example, the command output unit 220 obtains a route between two target points by interpolation. The command output unit 220 divides the determined route into N parts and determines coordinate values at the divided positions as interpolation points. Details of the interpolation process will be described later.

Furthermore, the command output unit 220 generates a motor angle command based on the coordinate values of the interpolation points. The motor angle command is a command that specifies the rotation direction and amount of rotation of the servo motor 60 that drives each of the joints J1 to J6. The memory 201 of the robot controller 200 stores in advance joint angle correspondence data that associates the positions of control points in the robot coordinate system with the combinations of rotation angles of the servo motors 60 that drive each of the joints J1 to J6. ing. The command output unit 220 sequentially outputs motor angle commands generated from the coordinate values of each interpolation point and the joint angle correspondence data to the motion control unit 230.

The operation control section 230 operates the servo motor 60 of each axis based on the motor angle command output from the command output section 220.

Control device 500 transmits operation commands to robot controller 200. Control device 500 is a computer located at a remote location. A remote location is a location where the worker operating the control device 500 cannot directly view the robot system 10. The control device 500 includes a memory 501 and a CPU 502. Memory 501 stores programs and data used for various processes executed by control device 500. A control program for controlling the robot system 10 is stored in the memory 501. When the CPU 502 executes the control program, an operation command is transmitted to the robot controller 200. The operation commands are transmitted to the robot controller 200 in the order in which they are executed.

Here, when receiving operation commands from the control device 500 in a remote location via the network, the robot controller 200 continues to be unable to receive operation commands from the control device 500 due to a communication error that occurs in the network. It is assumed that Even if the robot controller 200 cannot receive movement commands, if the number of movement commands stored in the memory 201 is greater than or equal to the number required for normally used interpolation processing, the robot controller 200 executes the interpolation process. Then, the robot 100 can be operated. However, if the number of motion commands stored in the memory 201 is less than the number required to execute the interpolation process, the robot controller 200 cannot execute the interpolation process.

Therefore, in the embodiment, the robot controller 200 selects different interpolation processes depending on the number of motion commands stored in the memory 201.

First, interpolation processing that is executed when the number of operation commands stored in the memory 201 is equal to or greater than a predetermined threshold will be described. A state in which the number of operation commands stored in the memory 201 is equal to or greater than a predetermined threshold is referred to as a normal state. In such a case, the robot controller 200 uses quintic spline interpolation as normal interpolation processing. The quintic spline interpolation used as normal interpolation processing is also referred to as first interpolation processing. Since the robot 100 moves along the interpolated path, it is desirable to avoid the movement of the robot 100 becoming steep and increasing the load on each joint of the robot 100. For this reason, in normal interpolation processing, curves are interpolated so that the routes between the plurality of target points become smooth.

FIG. 3 is a diagram for explaining a method of interpolating a route between a plurality of target points. It is assumed that the coordinate values of the target points specified in the operation commands received from the control device 500 are P0, P1, . . . , P11, and P12 in the order of reception. It is assumed that the target point P0 is the initial position of the control point. In FIG. 3, the coordinate values of the target point on the X-axis and the coordinate values of the target point on the Z-axis are shown. To facilitate understanding of the technology, the coordinate values of the target point on the Y-axis are not shown in FIG. However, it is assumed that the coordinate values indicating the target point included in the operation command received from the control device 500 include positions in each of the X-axis direction, Y-axis direction, and Z-axis direction. It is assumed that the command output unit 220 interpolates the route between the target points using the coordinate values of the three axes.

The command output unit 220 interpolates the route between the six target points using a spline curve using quintic spline interpolation using six motion commands. For example, the command output unit 220 uses the coordinate values of the target points P0, P1, . . . , P4, P5 and performs fifth-order spline interpolation to Interpolates a route between points specified by coordinate values. During the first correction, the command output unit 220 generates an interpolated path between at least the first target point P0 and P1, which is the first target point to be moved, among the target points specified by each of the six operation commands. Find the interpolation point that indicates . For example, the command output unit 220 divides the route between the target point P0, which is the initial position, and the first target point P1 into ten parts, and obtains coordinate values at the divided positions as interpolation points. After the interpolation process, the command output section 220 also outputs the first motion command among the six motion commands used, that is, the motion command that reached the command output section 220 first among the six motion commands. is deleted from the memory 201. The command output unit 220 outputs a motor angle command based on the coordinate values of the interpolation point to the operation control unit 230.

Further, the command output unit 220 executes the following interpolation process when the control point moves to the target point P1. In this case, the command output unit 220 uses the coordinate values of the target points P1, P2, ..., P5, P6 to perform fifth-order spline interpolation to Interpolates a route between points specified by coordinate values. The command output unit 220 obtains an interpolation point indicating an interpolation path between at least the target point P1, which is the current position of the control point, and the next target point P2, from among the target points specified by each of the six operation commands. . The command output unit 220 outputs a motor angle command based on the coordinate values of the interpolation point to the operation control unit 230. From now on, every time the control point reaches a certain target point, the command output unit 220 performs a process of interpolating the route between that point and the previous target point.

Next, an explanation will be given of an interpolation process that is executed when the number of operation commands stored in the memory 201 is less than a predetermined threshold. A state in which the number of operation commands stored in the memory 201 is less than a predetermined threshold is called an abnormal state. In such a case, the robot controller 200 uses linear interpolation between two points as temporary interpolation processing. Linear interpolation between two points used as temporary interpolation processing is also referred to as second interpolation processing.

FIG. 4 is a diagram for explaining another method of interpolating a route between a plurality of target points. It is assumed that the coordinate values of the target points specified in the operation commands received from the control device 500 are P0, P1, . . . , P9, and P10 in the order of reception. It is assumed that the target point P0 is the initial position of the control point. In FIG. 4, the coordinate values of the target point on the X-axis and the coordinate values of the target point on the Z-axis are shown. To facilitate understanding of the technology, the coordinate values of the target point on the Y-axis are not shown in FIG. However, it is assumed that the coordinate values indicating the target point included in the operation command received from the control device 500 include positions in each of the X-axis direction, Y-axis direction, and Z-axis direction. It is assumed that the command output unit 220 interpolates the route between the target points using the coordinate values of the three axes.

The command output unit 220 interpolates a route between the target points specified by the two operation commands by linear interpolation. Here, it is assumed that the threshold value for determining whether or not quintic spline interpolation can be executed is 6.

For example, assume that the number of operation commands stored in the memory 201 is five when the control point of the robot 100 moves to the target point P5. Note that the route to the target point P5 is interpolated by normal 5th-order spline interpolation. In this case, the command output unit 220 obtains a path connecting the target point P5, where the control point of the robot 100 is currently located, and the target point P6 with a straight line as an interpolated path. For example, the command output unit 220 divides the route between the target point P5 and the target point P6 into 10 parts, and obtains coordinate values at the divided positions as interpolation points. Further, after the interpolation process, the command output unit 220 outputs the first operation command of the two used operation commands, that is, the operation command that reached the command output unit 220 first among the two operation commands. is deleted from the memory 201. The command output unit 220 outputs a motor angle command based on the coordinate values of the interpolation point to the operation control unit 230.

Further, when the control point moves to the target point P6, the command output unit 220 performs quintic spline interpolation or linear interpolation between two points depending on the number of operation commands stored in the memory 201. Execute.

FIG. 5 is a flowchart of interpolation path generation processing executed by the robot controller 200. When the robot controller 200 receives a start command indicating the start of an operation from the control device 500, it starts an interpolation path generation process. The start command includes, for example, coordinate values specifying the target point P0, which is the initial position of the robot 100. Note that, in parallel with the interpolation path generation process, when the robot controller 200 receives operation commands from the control device 500, it is assumed that the robot controller 200 sequentially stores the received operation commands in the memory 201.

In step S101, if the execution conditions for the interpolation process are satisfied (step S101; YES), the robot controller 200 executes the process in step S102. The condition for executing the first interpolation process is that a predetermined number of operation commands are stored in the memory 201 after receiving the start command. On the other hand, if the execution conditions for the interpolation process are not satisfied (step S101; NO), the robot controller 200 waits. For example, the robot controller 200 may monitor the number of operation commands stored in the memory 201 at predetermined time intervals.

In step 102, the robot controller 200 executes the process in step 103 if the number of motion commands stored in the memory 201 is greater than or equal to the first threshold Th1 (step S102; YES). In the fifth-order spline interpolation, which is the first interpolation process, six motion commands are used, so the first threshold Th1 is 6. On the other hand, in step S102, if the number of motion commands stored in the memory 201 is less than the first threshold Th1 (step S102; NO), the robot controller 200 executes the process of step 106.

In step 103, the robot controller 200 executes quintic spline interpolation as a first interpolation process. The robot controller 200 reads from the memory 201 the six operation commands that arrived earliest from the control device 500. As described above, the operation commands are transmitted from the control device 500 to the robot controller 200 in the order in which they are executed. Therefore, the six action commands that are read out are action commands that are executed in consecutive order. The robot controller 200 calculates a path between at least the first motion command and the second motion command among the six motion commands by spline interpolation using six target points included in the six motion commands. Interpolate. Through the interpolation process, interpolation points indicating an interpolation path between the first motion command and the next motion command are determined. After the interpolation process is executed, the first motion command among the six motion commands used, that is, the motion command that reached the robot controller 200 first among the six motion commands used, is It is deleted from memory 201. After that, the robot controller 200 executes the process of step S104.

In step S104, the robot controller 200 causes the robot 100 to operate along the generated interpolated path. Therefore, the control point of the robot 100 sequentially moves through the positions indicated by the interpolation points between the first and second movement commands among the movement commands used for interpolation. After that, the robot controller 200 executes the process of step S105.

In step S105, if the end condition is not satisfied (step S105; NO), the process in step S101 is executed again. The termination condition is, for example, that the robot controller 200 has received a termination command from the control device 500. On the other hand, in step S105, if the termination condition is satisfied (step S105; YES), the interpolation path generation process is terminated.

In step S106, if the number of motion commands stored in the memory 201 is equal to or greater than the second threshold Th2 (step S106; YES), the robot controller 200 executes the process of step S107. In linear interpolation between two points, which is the second interpolation process, two motion commands are used, so the second threshold Th2 is 2. On the other hand, in step S106, if the number of motion commands stored in the memory 201 is less than the second threshold Th2 (step S106; NO), the robot controller 200 executes the process of step S108.

In step S107, the robot controller 200 executes linear interpolation between two points as a second interpolation process. The robot controller 200 reads from the memory 201 the two operation commands that arrived earliest from the control device 500. The robot controller 200 interpolates a route between the target points specified by the two movement commands by linear interpolation using the two target points included in the two movement commands. After the interpolation process is executed, the first motion command of the two motion commands used, that is, the motion command that reached the robot controller 200 first among the two motion commands used, is It is deleted from memory 201. Thereafter, in step S104, the robot controller 200 causes the robot 100 to operate along the generated interpolated path.

In step S108, the robot controller 200 outputs an error. For example, the robot controller 200 outputs a screen notifying that interpolation processing cannot be executed to a display device included in the robot controller 200. After that, the interpolation route generation process is finished.

As described above, in the embodiment, when the number of motion commands stored in the memory 201 is greater than or equal to the first threshold Th1, the robot controller 200 performs the fifth-order interpolation process, which is the first interpolation process. Interpolate between target points using spline interpolation. If the number of accumulated motion commands is less than the first threshold Th1 and greater than or equal to the second threshold Th2, the robot controller 200 uses linear interpolation between two points as a second interpolation process. , interpolate between target points.

In this way, when the number of motion commands stored in the memory 201 is less than the first threshold Th1 and the first interpolation process cannot be executed, the number of motion commands to be used is reduced from the first interpolation process. Less second interpolation processing is performed. Depending on the interpolated path, the movement of the robot 100 may become steep, and the load placed on each joint of the robot 100 may become large. It is possible to reduce the possibility that the operation of the robot 100 stops due to a shortage in the number of robots.

Further, when the number of operation commands stored in the memory 201 is less than the first threshold Th1 and greater than or equal to the second threshold, the second interpolation process is executed. Furthermore, the second interpolation process is executed until the number of operation commands stored in the memory 201 becomes less than the second threshold Th2. Compared to the conventional case where only one type of interpolation processing is used, it is possible to avoid stopping the operation of the robot 100 due to an insufficient number of operation commands.

Furthermore, for example, instead of the first interpolation process, a second interpolation process that uses fewer operation commands than the first interpolation process may be constantly executed. However, if the second interpolation process is always executed, it is assumed that the accuracy of the interpolation process will decrease. In the embodiment, since the interpolation process is selected according to the number of motion commands stored in the memory 201, the interpolation process can be performed while avoiding stopping the operation of the robot 100, compared to the case where the second interpolation process is always executed. Decrease in processing accuracy can be suppressed.

Further, as shown in FIG. 5, for example, after the second interpolation process is executed in step S107, when the number of operation commands stored in the memory 201 becomes equal to or greater than the first threshold Th1 in step S102, the step In S103, the first interpolation process is executed again. By performing the second interpolation process instead of the first interpolation process until the number of movement commands stored in the memory 201 reaches or exceeds the first threshold Th1, the robot 100 can continue to operate. Furthermore, when the number of operation commands stored in the memory 201 becomes equal to or greater than the first threshold Th1, the interpolation path can be generated again using highly accurate interpolation processing.

B1. Other embodiment 1
In the embodiment, as shown in FIG. 5, after the second interpolation process is executed, when the number of operation commands stored in the memory 201 becomes equal to or greater than the first threshold Th1, the first interpolation process is executed again. Ru. For example, the path interpolated based on the previously executed movement command is a path generated by linear interpolation between two points, and the path interpolated based on the next movement command is generated by quintic spline interpolation. Assume that the route is In this case, it is expected that the motion of the robot 100 will change rapidly due to switching of the interpolation process. Therefore, after the number of operation commands stored in the memory 201 reaches or exceeds the first threshold Th1, the first interpolation path to be generated is generated by an interpolation process other than the quintic spline interpolation in the first interpolation process. It's okay. After the number of motion commands stored in the memory 201 becomes equal to or greater than the first threshold value Th1 again, the robot controller 200 generates an interpolation path as follows for the first interpolation path to be generated.

FIG. 6 is a diagram for explaining an interpolation method in another embodiment 1. For example, assume that the route is interpolated by linear interpolation between the target points P1 and P4. It is assumed that the number of operation commands stored in the memory 201 is equal to or greater than the first threshold Th1 at the time when the control point of the robot 100 reaches the target point P4. In this case, first, the robot controller 200 generates an interpolated route RS by quintic spline interpolation using the six target points included in the six motion commands. In the example shown in FIG. 6, the interpolated route RS from target points P4 to P9 is represented by a broken line.

Further, among the interpolated routes RS, a route between the target point designated by the first motion command and the target point designated by the next motion command among the used motion commands is defined as an interpolated route R1. The interpolated route R1 is also referred to as a first route. In the example shown in FIG. 6, of the interpolated route RS, the route between target points P4 and P5 is set as the interpolated route R1. The robot controller 200 determines an interpolation point indicating an interpolation path R1 between the target point designated by the first motion command and the target point designated by the second motion command from among the used motion commands. For example, the robot controller 200 divides the interpolation route R1 into 10 parts and determines the coordinate values at the divided positions as interpolation points.

Furthermore, the robot controller 200 uses the first motion command and the second motion command among the six motion commands used in the fifth-order spline interpolation to create the interpolation path R2 by linear interpolation between two points. generate. The interpolated route R2 is also referred to as a second route. In the example shown in FIG. 6, the interpolated route R2 between the target points P4 and P5 is represented by a chain line. The robot controller 200 finds an interpolation point indicating an interpolation route R2 to the target point specified by the used motion command. For example, the interpolation route R2 is divided into 10 parts, and the coordinate values at the divided positions are determined as interpolation points.

The robot controller 200 determines coordinate values indicating a point between the interpolation point of the interpolation route R1 and the interpolation point of the corresponding interpolation route R2, and generates a route connecting the determined points as an interpolation route R3. do. The process of generating the interpolation route R3 is also referred to as third interpolation process.

The robot controller 200 causes the robot 100 to operate along the generated interpolation path R3. Thereafter, when it is time to execute the interpolation process and the memory 201 stores motion commands equal to or more than the first threshold value Th, the robot controller 200 uses the first interpolation process, which is the quintic spline interpolation, to determine the interpolation path. generate.

In another embodiment 1, when the number of motion commands stored in the memory 201 becomes equal to or greater than the first threshold Th1 again while executing the second interpolation process, the spline processing that is the first interpolation process is performed. A third interpolation process is performed using an interpolation route R1 generated by interpolation and an interpolation route R2 generated by linear interpolation, which is a second interpolation process. Thereafter, the first interpolation process is restarted. Therefore, when switching from the second interpolation process to the first interpolation process, sudden changes in the motion of the robot 100 can be suppressed, and the switch from the second interpolation process to the first interpolation process can be performed smoothly.

B2. Other embodiment 2
Furthermore, while executing the first interpolation process, if the number of motion commands stored in the memory 201 is less than the first threshold Th1 and greater than or equal to the second threshold Th2, the robot controller 200 performs the following operations. An interpolated path may be generated as follows. It is assumed that the robot controller 200 generates a route of five sections between target points specified by six motion commands every time it executes spline interpolation. Furthermore, it is assumed that information on the generated interpolation route is stored in the memory 201. For example, assume that at the time when the control point of the robot 100 reaches the target point P4, the number of operation commands stored in the memory 201 is less than the first threshold Th1 and greater than or equal to the second threshold Th2. It is assumed that the route to reach the target point P4 has been interpolated by spline interpolation. In this case, the robot controller 200 uses linear interpolation to interpolate the path between the target point P4, where the control point of the robot 100 is currently located, and the next target point P5. Furthermore, the robot controller 200 acquires, from the memory 201, information on interpolation points between target points P4 and P5 of the route generated by the spline interpolation executed immediately before.

The robot controller 200 determines coordinate values indicating a point between the interpolation point determined by linear interpolation and the interpolation point determined by the spline interpolation executed immediately before, and creates a route connecting the determined points. , generated as an interpolated path. The robot controller 200 operates the robot 100 along the generated interpolated path. Thereafter, when it is time to perform the interpolation process, and the number of motion commands stored in the memory 201 is less than the first threshold Th1 and greater than or equal to the second threshold Th2, the robot controller 200 performs the second interpolation process. An interpolated path is generated by linear interpolation.

In this way, in the second embodiment, when the number of operation commands stored in the memory 201 is less than the first threshold Th1 and greater than or equal to the second threshold Th2, the linear interpolation is performed before performing the linear interpolation. A route between an interpolation point indicating a route interpolated by the spline interpolation and an interpolation point indicating the route interpolated by the spline interpolation is used as the interpolation route. Therefore, compared to the case where the interpolation path generated by quintic spline interpolation is directly switched to the interpolation path generated by linear interpolation, it is possible to suppress a sudden change in the motion of the robot 100. In this way, it is possible to smoothly switch from the first interpolation process to the second interpolation process.

B3. Other embodiment 3
Alternatively, while executing the second interpolation process, after the number of motion commands stored in the memory 201 becomes equal to or greater than the first threshold Th1 again, the robot controller 200 may generate an interpolated path as follows. The robot controller 200 generates an interpolated path by circular interpolation using the two target points included in the two movement commands. The robot controller 200 operates the robot 100 along an interpolated path generated by circular interpolation. Thereafter, when it is time to execute the interpolation process and the memory 201 stores motion commands equal to or more than the first threshold value Th, the robot controller 200 uses the first interpolation process, which is the quintic spline interpolation, to determine the interpolation path. generate.

In this manner, in the third embodiment, when the number of motion commands stored in the memory 201 becomes equal to or greater than the first threshold value Th1 again, the arc The robot 100 is operated along the interpolated path generated by interpolation. Therefore, compared to the case where the interpolation path generated by linear interpolation is directly switched to the interpolation path generated by quintic spline interpolation, it is possible to suppress a sudden change in the motion of the robot 100. In this way, it is possible to smoothly switch from the second interpolation process to the first interpolation process.

B4. Other embodiment 4
Furthermore, while executing the second interpolation process, after the number of motion commands stored in the memory 201 becomes equal to or greater than the first threshold Th1 again, the robot controller 200 may generate an interpolated path as follows. The robot controller 200 generates an interpolated path by cubic spline interpolation using the four target points included in the four movement commands. The robot controller 200 operates the robot 100 along an interpolated path generated by cubic spline interpolation. Thereafter, when it is time to execute the interpolation process and the memory 201 stores motion commands equal to or more than the first threshold value Th, the robot controller 200 uses the first interpolation process, which is the quintic spline interpolation, to determine the interpolation path. generate.

In this manner, in the fourth embodiment, when the number of operation commands stored in the memory 201 becomes equal to or greater than the first threshold Th1 while executing the second interpolation process, the fifth-order The robot 100 is operated along an interpolated path generated by cubic spline interpolation, which has lower accuracy than spline interpolation. Thereafter, the quintic spline interpolation process, which is the first interpolation process, is restarted. Therefore, compared to the case where the interpolation path generated by linear interpolation is directly switched to the interpolation path generated by quintic spline interpolation, it is possible to suppress a sudden change in the motion of the robot 100. In this way, it is possible to smoothly switch from the second interpolation process to the first interpolation process.

B5. Other embodiment 5
Furthermore, the first interpolation process does not need to be quintic spline interpolation. For example, cubic spline interpolation may be used as the first interpolation process. Furthermore, the second interpolation process does not need to be linear interpolation. For example, circular interpolation between two points may be used as the second interpolation process.

In the embodiment, the robot controller 200 indicates an interpolated path between at least the target point P1, which is the current position of the control point, and the next target point P2, among the target points specified by each of the six movement commands. An example of finding interpolation points has been explained. However, the robot controller 200 may obtain all interpolated paths between the target points specified by each of the six motion commands.

In the embodiment, a method of interpolating a route between target points has been mainly described, but the configuration according to the embodiment can also be adopted for interpolating the speed or acceleration of movement of a control point of the robot 100.

The present disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary column of the invention may be used to solve some or all of the above-mentioned problems, or to achieve one of the above-mentioned effects. In order to achieve some or all of the above, it is possible to perform appropriate substitutions and combinations. Further, unless the technical feature is described as essential in this specification, it can be deleted as appropriate.

C. Other forms:
(1) According to one embodiment of the present disclosure, a route generation method for a robot system is provided. This route generation method for a robot system includes a receiving step of receiving a motion command specifying a target position of the robot from an external device and storing the motion command in a storage section; When the number of the plurality of operation commands specifying the target position further ahead and in which the order of execution of the operation commands is consecutive is greater than or equal to the first threshold Th1, By executing the first interpolation process using the movement commands, the target position specified by at least the first movement command among the Th1 movement commands and the target position specified by the next movement command are determined. a first interpolation step of interpolating a route including a path between the target position and the operation command, which is stored in the storage unit and specifies the target position beyond the current position; When the number of the plurality of operation commands whose execution order is consecutive is greater than or equal to a second threshold Th2 smaller than the first threshold Th1 and less than the first threshold Th1, Th2 of the operation commands are executed. By executing the second interpolation process using and a second interpolation step of interpolating a path between.
According to the above embodiment, when the number of motion commands stored in the storage unit is less than the first threshold Th1 and the first interpolation process cannot be executed, the number of motion commands to be used from the first interpolation process is By executing a small number of second interpolation processes, it is possible to avoid stopping the robot's motion due to an insufficient number of motion commands. Further, compared to a mode in which the second interpolation process, which uses fewer operation commands than the first interpolation process, is always executed, it is possible to suppress a decrease in the accuracy of the interpolation process.

(2) In the route generation method for a robot system according to the above aspect, if the number of the movement commands stored in the storage unit is less than the second threshold Th2, the second interpolation process cannot be executed. The method includes a step of outputting an error to notify the user of the error.
According to the above embodiment, if the number of operation commands stored in the storage unit is less than the second threshold Th2, an error is output to notify that the second interpolation process cannot be executed. If the number of operation commands stored in the ``second'' threshold Th1 is less than the first threshold Th1 and greater than the second threshold Th2, the second interpolation process is executed. According to the above embodiment, it is possible to avoid stopping the robot's motion due to an insufficient number of motion commands, compared to the conventional case where only one type of interpolation processing is used.

(3) In the route generation method for a robot system according to the above aspect, when the number of the motion commands stored in the storage section is less than the first threshold Th1, the motion commands stored in the storage section The execution of the second interpolation process is continued until the number becomes equal to or greater than the first threshold Th1.
According to the above embodiment, the robot's motion is controlled by executing the second interpolation process instead of the first interpolation process until the number of movement commands stored in the storage unit reaches or exceeds the first threshold Th1. It can be continued.

(4) In the route generation method for a robot system according to the above aspect, when the second interpolation process continues to be executed, the number of operation commands stored in the storage unit becomes equal to or greater than the first threshold Th1. If so, the first interpolation process is executed.
According to the above embodiment, if the number of operation commands stored in the storage unit becomes equal to or greater than the first threshold Th1 while the execution of the second interpolation process is continued, the accuracy of the second interpolation process is higher than that of the second interpolation process. Since the first interpolation process with a high value is executed again, it is possible to accurately interpolate routes between a plurality of target positions.

(5) In the route generation method for a robot system according to the above aspect, when the second interpolation process continues to be executed, the number of operation commands stored in the storage unit becomes equal to or greater than the first threshold Th1. In this case, before executing the first interpolation process, the operation commands specifying the target position beyond the current position are stored in the storage unit, and the order in which the operation commands are executed is consecutive. specifying the first route information generated by executing the first interpolation process using the Th1 movement commands and the target position beyond the current one stored in the storage unit; using second path information generated by executing the second interpolation process using Th2 of the operation commands in which the order of execution of the operation commands is consecutive; Then, the third interpolation process is executed.
According to the above embodiment, before switching from the second interpolation process to the first interpolation process, the information on the first route interpolated by the second interpolation process immediately before, and the information about the second route interpolated by the first interpolation process. By executing the third interpolation process using the above, it is possible to smoothly switch from the second interpolation process to the first interpolation process.

(6) According to another aspect of the present disclosure, a method of controlling a robot system is provided. This robot system control method includes a receiving step of receiving a motion command specifying a target position of the robot from an external device and storing the motion command in a storage section; When the number of the plurality of motion commands specifying the previous target position and in which the order of execution of the motion commands is consecutive is greater than or equal to the first threshold Th1, By executing the first interpolation process using the movement commands, the target position specified by at least the first movement command and the target position specified by the next movement command among the Th1 movement commands are determined. a first interpolation step for interpolating a route including a path to and from a target position; and the operation command, which is stored in the storage unit and specifies the target position beyond the current position, and the operation command is executed. If the number of the plurality of operation commands whose order is consecutive is equal to or greater than a second threshold Th2 smaller than the first threshold Th1, and less than the first threshold Th1, Th2 of the operation commands are used. By executing the second interpolation process, the distance between the target position specified by the first movement command and the target position specified by the next movement command among the Th2 movement commands is determined. a second interpolation step of interpolating the path of the robot; and an operation step of operating the robot along the interpolated path.
According to the above embodiment, the number of motion commands stored in the storage unit is less than the first threshold Th1, and the second interpolation process, which uses fewer motion commands than the first interpolation process, is performed to perform interpolation. Since the robot is operated along the route, it is possible to avoid stopping the robot's operation due to an insufficient number of operation commands. Furthermore, if the second interpolation process, which uses fewer operation commands than the first interpolation process, is constantly executed, it is assumed that the accuracy of the interpolation process will decrease. However, since the interpolation process is selected according to the number of movement commands stored in the storage unit, the accuracy of the interpolation process can be improved while avoiding stopping the robot's movement compared to when the second interpolation process is constantly executed. It is possible to suppress the decrease in

The present disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary column of the invention may be used to solve some or all of the above-mentioned problems, or to achieve one of the above-mentioned effects. In order to achieve some or all of the above, it is possible to perform appropriate substitutions and combinations. Further, unless the technical feature is described as essential in this specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10... Robot system, 50... Arm, 54... Arm element, 55... Arm element, 56... Arm element, 57... Arm element, 58... Arm element, 59... Arm element, 60... Servo motor, 60o... Output shaft, 65 ...Angle sensor, 70...Reducer, 70i...Input shaft, 80...End effector, 85...Force sensor, 90...Base, 100...Robot, 200...Robot controller, 201...Memory, 202...CPU, 210...Position Arithmetic unit, 220...Command output unit, 230...Movement control unit, 500...Control device, 501...Memory, 502...CPU, J1...Joint, J2...Joint, J3...Joint, J4...Joint, J5...Joint, J6... Joint, P1...program, Th1...first threshold, Th2...second threshold

Claims (6)

A path generation method for a robot system, the method comprising:
a receiving step of receiving a motion command specifying a target position of the robot from an external device and storing the motion command in a storage unit;
A first threshold value is the number of the plurality of operation commands that are stored in the storage unit and specify the target position beyond the current position, and the order in which the operation commands are executed is consecutive. If it is equal to or greater than Th1, by executing a first interpolation process using the Th1 movement commands, the target position specified by at least the first movement command among the Th1 movement commands is determined. a first interpolation step of interpolating a path including the target position specified by the next operation command;
The number of the plurality of operation commands, which are stored in the storage unit and which designate the target position beyond the current position, are consecutive in the order in which the operation commands are executed. When the second threshold Th2 is smaller than the threshold Th1 and is less than the first threshold Th1, by executing a second interpolation process using the Th2 operation commands, the number of Th2 operation commands is a second interpolation step of interpolating a path between the target position specified by the first movement command and the target position specified by the next movement command;
including,
Path generation method for robot system. A path generation method for a robot system according to claim 1, comprising:
If the number of the operation commands stored in the storage unit is less than the second threshold Th2, outputting an error notifying that the second interpolation process cannot be executed;
including,
Path generation method for robot system. A route generation method for a robot system according to claim 1 or 2, comprising:
When the number of the operation commands stored in the storage section becomes less than the first threshold Th1, until the number of the operation commands stored in the storage section becomes equal to or more than the first threshold Th1. , execution of the second interpolation process is continued;
Path generation method for robot system. A route generation method for a robot system according to claim 3, comprising:
performing the first interpolation process when the number of the operation commands stored in the storage unit becomes equal to or greater than the first threshold Th1 while the execution of the second interpolation process is continued;
Path generation method for robot system. A route generation method for a robot system according to claim 4,
When the number of the operation commands stored in the storage unit becomes equal to or greater than the first threshold Th1 while the execution of the second interpolation process is continued;
Before executing the first interpolation process, the operation commands specifying the target position beyond the current position are stored in the storage unit, and the order in which the operation commands are executed is consecutive. Information on the first route generated by executing the first interpolation process using Th1 movement commands, and the movement command that specifies the target position beyond the current position, which is stored in the storage unit. and a third path using the second path information generated by executing the second interpolation process using Th2 operation commands in which the order of execution of the operation commands is consecutive. perform interpolation processing,
Path generation method for robot system. A method for controlling a robot system, the method comprising:
a receiving step of receiving a motion command specifying a target position of the robot from an external device and storing the motion command in a storage unit;
A first threshold value is the number of the plurality of operation commands that are stored in the storage unit and specify the target position beyond the current position, and the order in which the operation commands are executed is consecutive. If it is equal to or greater than Th1, by executing a first interpolation process using the Th1 movement commands, the target position specified by at least the first movement command among the Th1 movement commands is determined. a first interpolation step of interpolating a route including the target position specified by the next operation command;
The number of the plurality of operation commands, which are stored in the storage unit and which designate the target position beyond the current position, are consecutive in the order in which the operation commands are executed. When the second threshold Th2 is smaller than the threshold Th1 and is less than the first threshold Th1, by executing a second interpolation process using the Th2 operation commands, the number of Th2 operation commands is a second interpolation step of interpolating a path between the target position specified by the first movement command and the target position specified by the next movement command;
an operation step of operating the robot along the complemented path;
including,
How to control a robot system.

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