JP2022188627A - Control method, control device, information processing method, information processing device, robot device, article manufacturing method, program, and recording medium - Google Patents

Abstract

To provide a control method in which a control value, at which stoppage of a robot can be executed so that dangerousness of breakage of hardware can be reduced as much as possible, can be obtained, even if all restrictions on shafts cannot be satisfied.SOLUTION: In the control method which stops a robot having at least a first joint and a second joint, when a control value at which a first physical restriction on the first joint and a second physical restriction on the second joint are satisfied, cannot be obtained, in obtaining a control value at which stoppage of the robot is executed, the control value is obtained so that either of the first physical restriction and the second physical restriction is satisfied preferentially, on the basis of a predetermined condition.SELECTED DRAWING: Figure 6

Description

The present invention relates to a robot control method and a robot information processing method.

2. Description of the Related Art In recent years, at production sites such as factories, automation of work such as assembly and transport has been promoted by a robot system having a robot arm having a plurality of joints and an end effector such as a hand or a tool on the robot arm. When operating the robot arm, the controller generates a target value (target angle) for each joint based on the target position, target velocity, interpolation method, etc. input by the user, and executes the desired motion. In such a robot system, it is necessary to immediately stop the robot arm and the end effector in order to ensure the safety of the user and the robot system when an operation unexpected for the user or some kind of abnormality occurs.

In the non-patent literature shown below, by introducing a parameter of the same dimension as the time axis of the normal operation, the movement path of the hand (end effector) of the robot system matches the normal operation and the stop operation. A method for calculating the target value is described. Calculate parameters based on various physical constraints such as acceleration, jerk, and torque on any axis, calculate the target values of other axes based on the parameters, and apply the calculated target values of each axis to the physical If the constraint is satisfied, the target value for each axis is adopted. Since the target value of each axis is calculated using the same parameter, it is guaranteed that the positional relationship of each axis is the same as the normal trajectory, and the path of the hand in normal operation and the path of the hand in stop operation are the same. becomes.

As a result, the end effector can be stopped on the same path as it should have traveled before stopping, and the risk of the end effector colliding with a surrounding object during stopping can be reduced. In addition, by observing physical restrictions in calculating the target value when stopping, it is possible to prevent a sudden deceleration command that places excessive demands on hardware such as arm links and reduction gears. The risk of hardware corruption can be reduced.

Friedrich Lange and Michael Suppa. "Trajectory Generation for Immediate Path-Accurate Jerk-Limited Stopping of Industrial Robots" Proc. Int. Conf. on Robotics and Automation (ICRA), May 2015

However, in the method described in Non-Patent Document 1, in obtaining the axis target values (control values) for stopping, if axis target values that satisfy the constraints of all axes cannot be calculated, A predetermined target value taught in advance in the operation of 1 is used as it is. Therefore, when the target value for each axis that satisfies the constraints of all axes cannot be calculated, sufficient consideration is not given to reducing the risk of hardware damage.

In view of the above problems, the present invention provides a control method capable of acquiring a control value that can execute a stop while reducing the risk of hardware damage as much as possible even when the constraints of all axes cannot be satisfied. I will provide a.

In order to solve the above problems, the present invention provides a control method for stopping a robot having at least a first joint and a second joint, wherein when acquiring a control value for executing the stop, If the control value that satisfies the first physical constraint and the second physical constraint at the second joint cannot be acquired, one of the first physical constraint and the second physical constraint is determined based on a predetermined condition. A control method characterized in that the control value is obtained so as to preferentially satisfy

According to the present invention, it is possible to acquire a control value that can execute a stop with the risk of hardware damage reduced as much as possible, even if constraints on all axes cannot be satisfied.

1 is a schematic diagram of a robot system 1000 in an embodiment; FIG. 1 is a control block diagram of a robot system 1000 in an embodiment; FIG. It is a control flow chart in the embodiment. 4 is a graph of trajectories in normal operation of the robot arm body 200 in the embodiment. FIG. 5 is a state trajectory graph showing parameters in an embodiment; FIG. FIG. 5 is a state trajectory graph showing parameters in an embodiment; FIG. 1 is a schematic diagram of a robot system 1000 in an embodiment; FIG. It is a control flow chart in the embodiment. 1 is a schematic diagram of an information processing device 800 according to an embodiment; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. It should be noted that the embodiment shown below is merely an example, and, for example, details of the configuration can be appropriately modified by those skilled in the art without departing from the scope of the present invention. Further, the numerical values taken up in the present embodiment are reference numerical values and do not limit the present invention. In the drawings below, arrows X, Y, and Z indicate the coordinate system of the entire robot system. In general, the XYZ three-dimensional coordinate system represents the world coordinate system of the entire installation environment. In addition, there are cases where the local coordinate system is appropriately used for robot hands, fingers, joints, etc., depending on convenience of control. In this embodiment, the world coordinate system, which is the overall coordinate system, is represented by XYZ, and the local coordinate system by xyz.

(First embodiment)
FIG. 1 is a schematic diagram showing a robot system 1000 in this embodiment. As shown in FIG. 1, a robot system 1000 includes a multi-joint robot arm body 200, an end effector 300 provided at the tip of the robot arm body 200, and a controller 400 that controls the robot arm body 200 and the end effector 300. It has Also provided are a workpiece 600 operated using the robot arm main body 200 and the end effector main body 300, a mounting table 500 on which the workpiece 600 is placed, and a signal input device 700 for transmitting the presence or absence of the workpiece to the control device 400. Further, an external input device 800 for inputting command values to the robot arm main body 200 and the end effector main body 300 is provided.

The robot arm body 200 includes a base 210 that contacts the ground, and five links 201, 202, 203, 204, and 205. It also has five joints J1, J2, J3, J4, and J5 that connect these links 201 to 205 so as to be rotatable in the directions of the arrows shown in FIG. Also, the joints J1-J5 have arm motors 211-215 for swinging or rotating the links 201-205 (FIG. 2). Each of the arm motors 211 to 215 is equipped with a speed reducer (shown in the attached drawing) that reduces the rotation of the motor and generates torque for rotating each of the links 201 to 205 . Furthermore, encoders 221 to 225 (FIG. 2) are provided at the joints J1 to J5, and the angle of each joint is detected from each encoder and fed back to the control device 400. FIG. By positioning each link at a predetermined position, the end effector body 300 can be positioned at a predetermined position in the XYZ space.

The end effector body 300 is a robot hand, and includes fingers 301 and 302, a hand motor 312 (FIG. 2) for opening and closing the fingers 301 and 302 toward or away from each other, and a speed reducer shown in the accompanying drawings. there is The robot system 1000 grips a workpiece 600 with the end effector body 300 and performs processing such as bringing it into contact with another workpiece. By doing so, it is possible to use the work 600 and another work as materials, and manufacture an article in which the work 600 and the other work are combined as a product. Further, the hand motor 312 is provided with an encoder 322 ( FIG. 2 ) from which the speed of the hand motor 312 is detected and fed back to the control device 400 . In this embodiment, the robot hand is used as an example of the end effector main body 300, but the end effector body 300 is not limited to this. For example, a tool such as an electric screwdriver or an end mill may be used.

FIG. 2 is a block diagram showing the detailed configuration of the control system of the robot system 1000 of FIG. The control device 400 is configured by a computer and includes a CPU (Central Processing Unit) 401 as a processor. It also has a ROM (Read Only Memory) 402, a RAM (Random Access Memory) 403, a HDD (Hard Disc Drive) 404, and a recording disc drive 405 as storage units. It also has interfaces 406, 407, 408, 409, 410, and 411 for communicating with each device. The CPU 401, ROM 402, RAM 403 and interfaces 406 to 412 are connected via a bus 412 so as to be able to communicate with each other.

Among them, the RAM 403 is used for temporarily storing data such as teaching points and control commands by operating the external input device 800 . The ROM 402 stores a basic program 430 such as BIOS for causing the CPU 401 to execute various kinds of arithmetic processing. The CPU 401 executes various arithmetic processes based on control programs recorded (stored) in the HDD 404 . The HDD 404 is a storage unit that stores various data and the like that are results of arithmetic processing by the CPU 401 . The recording disk drive 405 can read various data, control programs, and the like recorded on the recording disk 431 . Further, the interfaces 407 and 408 are connected to a monitor 811 on which various images are displayed and an external storage device 812 such as a rewritable non-volatile memory or an external HDD.

The external input device 800 can be, for example, an operation device such as a teaching pendant (TP), but may be another computer device (PC or server) capable of editing a robot program. The external input device 800 can be connected to the control device 400 via wired or wireless communication connection means, and has user interface functions such as robot operation and status display. The target joint angles of the joints J1 to J5 input by the external input device 800 are output to the CPU 401 via the interface 406 and the bus 412 .

The CPU 401 receives teaching point data input from the external input device 800 through the interface 406 . Also, based on the teaching point data input from the external input device 800, the trajectory of each axis of the robot arm body 200 is generated and transmitted to the arm motors 211 to 215 via the interface 409 using the arm motor driver 230. be able to. The CPU 401 outputs drive command data indicating the control amount of the rotation angle of each of the arm motors 211 to 215 to the arm motor driver 230 via the bus 412 and the interface 409 at predetermined intervals.

The arm motor driver 230 calculates the amount of current output to each of the arm motors 211 to 215 based on the drive command received from the CPU 401, supplies the current to each of the arm motors 211 to 215, and Joint angle control of joints J1 to J5 is performed. It also outputs pulse signals from the encoders 221 to 225 described above to the CPU 401 via the interface 409 and the bus 412 . That is, the CPU 401 feeds back the arm motors 211 to 215 via the arm motor driver 230 so that the joint angle current values of the joints J1 to J6 detected by the respective encoders 221 to 225 become the target joint angles. Execute control.

The controller 400 is also connected to a hand motor 312 via an interface 410 and a hand motor driver 330 . The hand motor driver 330 calculates the amount of current to be output to the hand motor 312 based on the drive command input from the CPU 401, supplies the current to the hand motor 312, and controls the speed of the hand motor 312. I do. Also, the pulse signal from the encoder 322 described above is output to the CPU 401 via the interface 410 and the bus 412 . That is, the CPU 401 executes feedback control of the hand motor 312 via the hand motor driver 330 so that the current value of the speed of the hand motor 312 detected by the encoder 322 becomes the target speed.

Furthermore, the control device 400 is also connected to the signal input device 700 via an interface 411 and a bus 412 . The mounting table 500 is equipped with a sensor capable of detecting the presence or absence of the workpiece 600, such as a pressure sensor (not shown). Signal input device 700 outputs a signal indicating the presence or absence of work 600 to CPU 401 via interface 411 and bus 412 based on the detection result of the pressure sensor. The CPU 401 can determine whether or not the workpiece 600 is present on the mounting table 500 based on the signal from the signal input device 700, and can control the robot arm body 200 and the end effector body 300 based on the determination.

Here, the robot arm main body 200 is executing an operation of moving the end effector main body 300 to a predetermined position on the mounting table 500 in order to carry the work 600 to another work location based on the command from the control device 400. shall be During this operation, the signal input device 700 detected by the control device 400 that the work 600 had not reached the predetermined position. If this continues, the operation will continue without gripping the workpiece 600, resulting in poor work efficiency. You need to let users perform maintenance. The stopping process of the robot arm body 200 in this embodiment will be described in detail below.

FIG. 3 is a control flow chart showing processing of a method for acquiring an axis target value (control value) for stopping the robot arm body 200 in this embodiment. The flowchart in FIG. 3 consists of steps S1 to S7. The contents of each process in steps S1 to S7 will be described in detail below with reference to the drawings. Also, the following processing is assumed to be executed by the CPU 401 of the control device 400 .

First, in step S1, an axis target value (ordinary axis target value) for each joint (each axis) for executing a normal motion is obtained. The embodiment can be applied to any number of axes as long as it controls a robot device having two or more joints. This time, for the sake of simplification of explanation, the control of two joints will be described in detail as an example.

FIG. 4 is a graph showing axis target values (normal axis target values) in normal operation acquired in step S1. FIG. 4(a) shows the normal axis target value of the first joint, and FIG. 4(b) shows the normal axis target value in the normal motion of the second joint. In FIGS. 4A and 4B, the horizontal axis indicates the time step k, and the vertical axis indicates the axis target value [deg]. i is a value indicating the first joint or the second joint, and FIG. 4(a) indicates the normal axis target value for the first joint, and FIG. 4(b) indicates the normal axis target value for the second joint. The time step is set by the control period of the robot arm main body 200 .

From FIG. 4A, the normal axis target value qd1(k) when the range of the time step k of the first joint is 0≦k≦5 is qd1(k)=[0, 0.550, 0.950, 1 .200, 1.275, 1.350]. From FIG. 4(b), the normal axis target value qd2(k) when the range of the time step k of the second joint is 0≦k≦5 is qd2(k)=[0, 0.100, 0.270, 0 .530, 0.900, 1.200]. This time, in order to receive a stop command at time step k=3 and switch from normal operation to stop operation later in time than k=3, the normal axis target value is set to stop later in time than k=3. change.

Next, in step S2, based on the stop command, the axis target value (restricted axis target value) when decelerating each joint while complying with the limits of the physical constraints is obtained. Specifically, as physical constraints, limit values (upper limits) such as acceleration, jerk (jerk), and torque can be considered. This time, the case of limiting the acceleration will be explained as an example. In the following description, qci(k) [deg] represents the axis target value (stop axis target value) for the stopping operation on axis i at time step k. Let vci(k) [deg] be a value obtained by multiplying the speed by the time step width. Then, when the value obtained by multiplying the acceleration limit value for the axis i by the square of the time step width is ai' [deg], the axis target value (limit axis target value) qai ( k) [deg] can be calculated by equation (1).

In this embodiment, the limit value of acceleration of each joint is the value of equation (2).

At this time, the limit axis target value of the first joint at time step k=4 is the value of equation (3).

Similarly, the limit axis target value of the second joint is the value of equation (4).

Although the acceleration constraint is considered in this embodiment, it is also possible to consider the torque constraint and the jerk constraint at the same time. In that case, among the limit axis target values calculated based on each physical constraint, the limit axis target value that is the farthest (farthest) from the current joint value (angle) may be adopted in step S2.

Next, in step S3, a parameter Sai(k) obtained by projecting the limit axis target value calculated in step S2 onto the time axis is obtained. FIG. 5 is a diagram showing a limit axis target value and parameters obtained by projecting it onto the time axis. FIG. 5(a) shows the axis target value for the first joint, and FIG. 5(b) shows the axis target value for the second joint.

As shown in FIGS. 5 and 6, the parameter Sai(k) can be obtained by linearly interpolating the normal axis target value in normal operation. 6).

Here, the reason why the time steps for acquiring the parameters are different between the equations (5) and (6) is based on the following reason. The limit axis target value qa1(4) of the first joint exceeds the normal axis target value qd1(4) of the normal trajectory, while the limit axis target value qa2(4) of the second joint exceeds the normal axis target value of the normal trajectory. below qd2(4). Therefore, since the parameter Sa2(4) cannot be obtained by linear interpolation between time steps 4 and 5, time steps 3 and 4 are used.

Next, in step S4, a candidate for the stop axis target value of each joint is obtained from the parameters of each joint obtained in step S3. FIG. 6 is a diagram showing each parameter in a graph of a normal trajectory at the first joint and a graph of a normal trajectory at the second joint. The upper graph in FIG. 6 is the normal trajectory graph for the first joint, and the lower graph in FIG. 6 is the normal trajectory graph for the second joint.

First, the stop axis target value for each joint is obtained from the parameter Sa1(4) obtained from the limit axis target value for the first joint. The stop axis target value at the first joint is equal to the limit target value obtained in step 2, and is the value shown in equation (7).

On the other hand, the stop axis target value at the second joint can be obtained by linear interpolation from the normal axis target value in normal motion, and is the value shown in equation (8).

Subsequently, the stop axis target value for each joint is obtained from the parameter Sa2(4) obtained from the limit axis target value for the second joint. The stop axis target value at the first joint can be obtained by linear interpolation from the normal axis target value in normal motion, and is the value shown in equation (9).

On the other hand, the stop axis target value at the second joint is equal to the limit axis target value obtained in step S2, and is the value shown in Equation (10).

Next, in step S5, it is determined whether or not there is a stop axis target value that satisfies the physical constraints of all axes (all joints) among the candidates for the stop axis target value obtained in step S4.

First, when adopting the stop axis target value obtained from the parameter Sa1(4), it is determined whether the absolute value of the acceleration of each axis exceeds the physical constraint. The stop axis target value at the first joint is the value shown in formula (7), and the value obtained from the acceleration constraint values of the first and second joints from formula (2), so the acceleration at the first joint exceeds the constraint. do not.

On the other hand, the value of the acceleration at the second joint when the stop axis target value obtained from the parameter Sa1(4) is adopted is the value shown in Equation (11).

From equations (2) and (11), the acceleration value at the second joint when the stop axis target value obtained from the parameter Sa1(4) is adopted is the acceleration constraint value a2′ at the second joint=0. Over 150. Therefore, the stop axis target value calculated from the parameter sa1(4) is not a stop axis target value that satisfies the physical constraints of all axes.

Subsequently, when the stop axis target value obtained from the parameter Sa2(4) is adopted, it is determined whether the absolute value of the acceleration of each axis exceeds the physical constraint. The stop axis target value at the second joint has the value shown by the formula (8), and is the value obtained from the acceleration constraint value of the second joint from the formula (4), so the acceleration at the second joint does not exceed the constraint.

On the other hand, the value of the acceleration at the first joint when the stop axis target value obtained from the parameter Sa2(4) is adopted is the value shown in Equation (12).

From equations (2) and (12), the value of the acceleration at the first joint when the stop axis target value obtained from the parameter Sa2(4) is adopted is the acceleration constraint value a1′ at the first joint=0. Over 150. Therefore, the stop axis target value obtained from the parameter Sa2(4) is not a stop axis target value that satisfies the physical constraints of all axes.

Here, if there is a stop axis target value that satisfies the physical constraints of all axes among the candidates for the stop axis target value acquired in step S4, step S5 returns No, and the process proceeds to step S7. move on. If there is a stop axis target value that satisfies the physical constraints of all axes among the candidates for the stop axis target value acquired in step S4, step S5: Yes, the process proceeds to step S6, and the physical constraint of all axes is determined. The robot arm main body 200 is stopped using the stop axis target value that satisfies the following.

Here, as in this case, if there is no stop axis target value that satisfies the physical constraints of all axes, it will not be possible to execute the stop. Therefore, in order to satisfy the physical constraints as much as possible and stop the motor even in such a case, in step S7, the stop axis target value acquired in step S4 is evaluated based on an evaluation method (predetermined conditions) prepared in advance. do. A significant feature is that a stop axis target value with a high evaluation value is used as the stop axis target value for stopping the robot arm body 200 .

The method of determining the stop axis target value in step S7 in this embodiment is based on the speed of each joint at the time step (k=3 in this embodiment) when the stop command is received, and the physical Priority is given to constraints to determine the stop axis target value. The stop axis target value obtained by the parameter Sai(k) obtained by the constraint of the joint with high speed at the time step when the stop command is received is used as the stop axis target value for stopping the robot arm main body 200. use.

The speed of each joint at the time step when the stop command is received is the value shown in equations (13) and (14).

From equations (13) and (14), the velocity of the second joint is the highest, so the stop axis target value candidate obtained by the parameter Sa2(4) obtained by the physical constraint of the second joint is used. The stop axis target value obtained by the parameter Sa2(4) at the first joint is qc1(4)=1.222 from equation (9), and the stop axis target value at the second joint is qc2 from equation (4). (4)=0.640. At this time, the absolute value of acceleration at the first joint is |ac1(4)|=0.228 from equation (12), and the absolute value of acceleration at the second joint is |ac2(4)| = a2' = 0.1500. As described above, the stop axis target value can be determined while observing the physical restrictions for the axis operating at the highest speed (the second joint in this case). In this embodiment, the physical constraint of the first joint and the physical constraint of the second joint are the same, but they may be different.

By repeating the above operation, the robot arm main body 200 can be stopped while observing the physical restrictions as much as possible with respect to the axis operating at the highest speed. This preferentially adheres to physical constraints at joints with high velocities and high loads on the transmission mechanism. Therefore, even if it is not possible to obtain a stop axis target value that satisfies the constraints of all joints (axes), physical Constraint-satisfying stops can be enforced.

In the above-described embodiment, the physical constraint of the joints to be prioritized is determined based on the speed of each joint in the time step when the stop command is received, but the present invention is not limited to this. For example, prioritization may be given to the physical constraint of the joint that reaches the highest speed in the time step up to the time before receiving the stop command (before the timing of k=3). Alternatively, a predetermined threshold value for velocity may be set in advance, and physical constraints may be given priority to the joint that has reached the threshold value the most times in the time step before the stop command is received.

(Second embodiment)
Next, a second embodiment of the present invention will be described in detail. This embodiment differs from the above-described first embodiment in the method of determining the stop axis target value in step S7. In this embodiment, among the stop axis target values in step S4, the joint with the least amount of excess over the physical constraint at the time step at which the stop is performed (k=4, one time step after k=3 when the stop command is received) Determine the stop axis target value using the physical constraints in . In the following description, hardware and control system configurations that are different from those of the first embodiment will be illustrated and described as necessary. In addition, it is assumed that the same parts as those of the first embodiment can have the same configurations and functions as those described above, and detailed description thereof will be omitted.

The stop axis target value calculated from the parameter Sa1(4) by Equation (9) exceeds the acceleration constraint value of the second joint by 0.210/0.150=1.40 times. On the other hand, the stop axis target value calculated from the parameter Sa2(4) by Equation (12) exceeds the acceleration constraint value of the second joint by 0.228/0.150=1.52 times. Therefore, when actually stopping, using the parameter Sa1(4) at the first joint can suppress the excess of the physical constraint.

As described above, even if the stop axis target value that satisfies the constraints of all joints (axes) cannot be obtained, the risk of damage to the hardware (robot arm body 200) can be reduced as much as possible. A stop that satisfies physical constraints can be performed.

(Third embodiment)
Next, the third embodiment of the present invention will be described in detail. This embodiment differs from the above-described first and second embodiments in the method of determining the stop axis target value in step S7. In the following, parts of the hardware and control system configurations that differ from those of the above-described embodiments will be illustrated and explained as necessary. Also, the same parts as those of the first embodiment can have the same configurations and functions as those described above, and detailed descriptions thereof will be omitted.

In this embodiment, the limit axis target value obtained by the formulas (3) and (4) is adopted instead of using the stop shaft target value calculated in step S4. As a result, even if a stop axis target value that satisfies the constraints of all joints (axes) cannot be calculated, a stop can be executed that reduces the risk of hardware (robot arm body 200) damage. Note that the acquisition of the stop axis target value satisfying the physical constraints of all joints and the acquisition of the stop axis target value satisfying the physical constraints of any joint may be switched.

(Fourth embodiment)
Next, the fourth embodiment of the present invention will be described in detail. This embodiment differs from the above-described first and second embodiments in the method of determining the stop axis target value in step S7. In the following, parts of the hardware and control system configurations that differ from those of the above-described embodiments will be illustrated and explained as necessary. Also, the same parts as those of the first embodiment can have the same configurations and functions as those described above, and detailed descriptions thereof will be omitted.

In the present embodiment, a case in which the acquired stop command is related to the worker will be described as an example. In the case of a worker-related stop, it is necessary to stop the robot arm body 200 immediately to ensure the safety of the worker. Therefore, the control device 400 stops the robot arm body 200 so as to stop at the current position regardless of whether the physical constraint is satisfied at the acquired stop axis target value.

FIG. 7 shows a robot system 1000 in this embodiment. The base 210 of the robot arm body 200 in this embodiment is provided with a detection sensor 260 for detecting a worker. The detection sensor 260 is a light irradiation type sensor, and when the irradiated light is reflected by the worker, it acquires the reflected light and detects the presence or absence of the worker. When the worker is detected, a signal is transmitted to the control device 400 as a stop command due to the approach of the worker. In this embodiment, an optical sensor is used, but the present invention is not limited to this, and a sensor that can detect a worker, such as a magnetic sensor or an imaging device, may be used.

FIG. 8 is a diagram showing a control flow chart in this embodiment. Compared to the above-described embodiment, this embodiment differs in that steps S21 and S22 exist. Further, the following processing is assumed to be executed by the CPU 401 of the control device 400, and steps S21, S22, and S23, which are different steps, will be described in detail.

As shown in FIG. 8, in this embodiment, before proceeding to step S1, in step S21, a step of determining whether or not the stop command is due to the worker's approach is provided. Step S21: Yes, that is, if there is a stop command due to the approach of the worker, the process proceeds to step S22. If it is not due to the approach of the operator, step S21: No, the process proceeds to step S1, and the stop processing based on the various embodiments described above is performed.

In step S22, the robot arm body 200 is immediately stopped to ensure the safety of the operator. Switch to the process to stop.

Then, in step S23, the robot arm body 200 is stopped using the current positions of the joints of the robot arm body 200 as stop axis target values in order to stop immediately regardless of physical restrictions.

As described above, the robot arm main body 200 can be stopped immediately by acquiring the stop command, so that the safety of the operator can be reliably ensured. In addition, since the robot arm body 200 is immediately stopped, the hardware of the robot arm body 200 can be prevented from being damaged by, for example, a safety tool worn by the worker due to contact between the robot arm body 200 and the worker. can be reduced as much as possible.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described in detail. The various embodiments described above describe the stopping operation of the robot arm body 200 in the actual machine. However, the present invention can also be implemented in an information processing device (simulation device) that simulates a robot arm. Details are given below.

FIG. 9 is a schematic diagram of an information processing device 900 for simulating the motion of the robot arm body 200 in this embodiment. The information processing apparatus 900 is a desktop personal computer equipped with an OS (Operating System) 901 , a display 902 , a keyboard 903 and a mouse 904 .

The OS 901 stores CAD data of the robot arm main body 200 and the robot hand main body 300, and a trajectory generation engine equivalent to the controller 400 of the actual machine. A simulation screen 905 of the robot arm body 200 is displayed on a display 902 serving as a display unit. Also, a normal operation execution button 906, a stop button 907, a stop button 908, a stop button 909, and a stop button 910 are displayed.

Here, the stop button 907 is a button for simulating the stop processing in the above-described first embodiment. A stop button 908 is a button for simulating the stop processing in the above-described second embodiment. A stop button 909 is a button for executing the simulation of the third embodiment described above. A stop button 910 is a button for executing the simulation of the fourth embodiment described above.

The operator uses the keyboard 903 and/or the mouse 904 to input predetermined information (trajectory data of the normal trajectory, etc.), and clicks the normal action execution button 906 to execute the motion simulation of the robot arm body 200. can be done. One of stop button 907, stop button 908, stop button 909, and stop button 910 is clicked during normal operation reproduction. When clicked, it is assumed that a stop command was output at the timing of the click, and then the above-described embodiment is applied to execute stop processing for acquiring the stop axis target value. As a result, it is possible to confirm, through simulation, a plurality of types of stop motions that reduce the risk of hardware damage to the robot arm body 200 under various conditions.

(Other embodiments)
The processing procedures of the above-described embodiments are specifically executed by the control device or the information processing device. Therefore, a recording medium recording a software program capable of executing the functions described above is supplied to a device that integrates the respective control devices, and the CPU that performs integrated processing reads out and executes the program stored in the recording medium. can be configured to achieve In this case, the program itself read from the recording medium implements the functions of the above-described embodiments, and the program itself and the recording medium recording the program constitute the present invention.

In each embodiment, the computer-readable recording medium is each ROM, each RAM, or each flash ROM, and the case where the control program is stored in the ROM, RAM, or flash ROM has been described. However, the present invention is not limited to such a form. A control program for carrying out the present invention may be recorded on any computer-readable recording medium. For example, an HDD, an external storage device, a recording disk, or the like may be used as a recording medium for supplying the control program.

Further, in the various embodiments described above, the robot arm main body 200 uses a multi-joint robot arm having a plurality of joints, but the number of joints is not limited to this. Although a vertical multi-axis configuration is shown as the type of robot arm, a configuration equivalent to the above can also be implemented with a different type of joint such as a parallel link type.

In the above-described embodiment, the physical constraints of the joints to be prioritized are determined based on the velocity and acceleration of each joint in the time step when the stop command is received. , any physical quantity can be used.

Further, in the above-described embodiment, the speed of the joint is directly acquired by the sensor, but the present invention is not limited to this. For example, a sensor may be provided in the robot hand main body 300, and based on the physical quantity occurring in the robot hand main body 300, the physical quantity occurring in each joint may be acquired and implemented.

Further, the various embodiments described above are applicable to machines capable of automatically performing operations such as expansion, contraction, bending and stretching, vertical movement, horizontal movement, turning, or a combination of these operations, based on information stored in a storage device provided in the control device. It is possible.

The present invention is not limited to the above-described embodiments, and many modifications are possible within the technical concept of the present invention. Moreover, the effects described in the embodiments of the present invention are merely enumerations of the most suitable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

200 robot arm main body 201, 202, 203, 204, 205 link 210 base 300 robot hand main body 301, 302 finger 400 control device 500 mounting table 600 work 700 signal input device 800 external input device 900 information processing device 901 OS
902 Display 903 Keyboard 904 Mouse 905 Simulation screen 906 Normal operation execution button 907, 908, 909, 910 Operation stop button 1000 Robot system J1, J2, J3, J4, J5 Joint

Claims (27)

A control method for stopping a robot having at least a first joint and a second joint,
When acquiring the control value for executing the stop, if the control value that satisfies the first physical constraint at the first joint and the second physical constraint at the second joint cannot be acquired, based on a predetermined condition , obtaining the control value so as to preferentially satisfy either the first physical constraint or the second physical constraint;
A control method characterized by: In the control method according to claim 1,
The predetermined condition includes a first physical quantity occurring at the first joint at the first timing when the instruction to execute the stop is obtained, and a second physical quantity occurring at the second joint at the second timing. A condition that prioritizes either the first physical constraint or the second physical constraint based on
A control method characterized by: In the control method according to claim 2,
Based on the first physical quantity and the second physical quantity, prioritizing the physical constraint at the joint where the physical quantity having the larger value occurs;
A control method characterized by: In the control method according to claim 2,
The predetermined condition is based on the first physical quantity and the second physical quantity before the first timing, and gives priority to the physical constraint at the joint where the physical quantity having the largest value occurs.
A control method characterized by: In the control method according to claim 2,
The predetermined condition is based on the first physical quantity and the second physical quantity before the first timing, and gives priority to the physical constraint in the joint with the largest number of times that a predetermined threshold has been reached.
A control method characterized by: In the control method according to claim 2,
The predetermined condition includes the first physical quantity that will occur at the first joint at a second timing after the first timing and the second physical quantity that will occur at the second joint at the third timing. and a condition that prioritizes either the first physical constraint or the second physical constraint based on
A control method characterized by: In the control method according to claim 6,
Based on the first physical quantity and the third physical quantity at the second timing, prioritizing the physical constraint at the joint where the physical quantity having the smaller excess amount with respect to the predetermined threshold will occur,
A control method characterized by: In the control method according to claim 6 or 7,
The second timing is a timing one time step after the first timing,
A control method characterized by: In the control method according to claim 8,
the time step is set by a control cycle of the robot;
A control method characterized by: In the control method according to any one of claims 1 to 9,
The control value is
a first target value that satisfies the first physical constraint and the second physical constraint and can perform the stop;
a parameter obtained based on the first target value;
a second target value obtained based on the parameter, and
A control method characterized by: In the control method according to claim 10,
the parameter is obtained based on the first target value and trajectory data for operating the robot;
A control method characterized by: In the control method according to claim 11,
The parameter is obtained by linearly interpolating the first target value and the trajectory data,
A control method characterized by: In the control method according to any one of claims 10 to 12,
using the first target value as the control value to perform the shutdown;
A control method characterized by: In the control method according to any one of claims 1 to 13,
The first physical quantity and the second physical quantity are velocity, acceleration, jerk, torque, or load,
A control method characterized by: In the control method according to any one of claims 1 to 14,
Acquiring the first physical quantity and the second physical quantity based on a third physical quantity applied to the hand of the robot;
A control method characterized by: In the control method according to claim 1,
When obtaining the control value, when either the first physical constraint or the second physical constraint is preferentially satisfied, or when the first physical constraint and the second physical constraint are satisfied. to switch between
A control method characterized by: In the control method according to claim 1,
Switching when executing the stop by acquiring the control value that does not satisfy the first physical constraint and the second physical constraint based on the stop;
A control method characterized by: 18. The control method of claim 17,
the stop being associated with a worker;
A control method characterized by: A method for manufacturing an article, comprising: controlling the robot using the control method according to any one of claims 1 to 18 to manufacture an article. A control device for stopping a robot having at least a first joint and a second joint,
When acquiring the control value for executing the stop, if the control value that satisfies the first physical constraint at the first joint and the second physical constraint at the second joint cannot be acquired, based on a predetermined condition , obtaining the control value so as to preferentially satisfy either the first physical constraint or the second physical constraint;
A control device characterized by: A robot device comprising the control device according to claim 20 and the robot. An information processing method for executing a simulation regarding a stop of a robot having at least a first joint and a second joint,
When acquiring the control value for executing the stop, if the control value that satisfies the first physical constraint at the first joint and the second physical constraint at the second joint cannot be acquired, based on a predetermined condition , obtaining the control value so as to preferentially satisfy either the first physical constraint or the second physical constraint;
performing the simulation of the robot based on the control value;
An information processing method characterized by: In the information processing method according to claim 22,
There are a plurality of types of simulation,
Displaying buttons for executing a plurality of types of simulations on the display unit;
An information processing method characterized by: An information processing device for executing a simulation regarding a stop of a robot having at least a first joint and a second joint,
When acquiring the control value for executing the stop, if the control value that satisfies the first physical constraint at the first joint and the second physical constraint at the second joint cannot be acquired, based on a predetermined condition , obtaining the control value so as to preferentially satisfy either the first physical constraint or the second physical constraint;
performing the simulation of the robot based on the control value;
An information processing device characterized by: In the information processing device according to claim 24,
There are a plurality of types of simulation,
Displaying buttons for executing a plurality of types of simulations on the display unit;
An information processing device characterized by: A program capable of executing the control method according to any one of claims 1 to 18 or the information processing method according to claim 22 or 23. A computer-readable recording medium storing the program according to claim 26.

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