JP7251814B2 - ROBOT CONTROL SYSTEM, ROBOT CONTROL METHOD, AND PROGRAM - Google Patents

Description

The present invention relates to a robot control system, a robot control method, and a program.

For example, in Patent Document 1, a device for detecting a contact position where a robot contacts an object includes a probe attached to the robot and elastically displaceable in the direction of contact with the object, and a probe attached to the robot during operation. A probe position calculation unit that calculates the position of the probe, a contact detection unit that detects a state in which the probe is in contact with an object, and when the contact state of the probe is detected, the calculated position of the probe and a touch position calculator for deriving the touch position based on.

JP 2011-230234 A

An object of the present invention is to provide a robot control system that controls a robot more safely and efficiently.

A robot control system according to the present invention includes a trajectory storage unit that stores a trajectory of a robot's motion, a forwarding unit that moves the robot, and a detection unit that detects that the robot, which is operated by the forwarding unit, has come into contact with an obstacle. and a reversing unit that reverses the robot from the position of contact with the obstacle based on the trajectory stored by the trajectory storage unit when the detection unit detects contact with the obstacle. , and a stop section for stopping the movement of the robot reversed by the reversing section.

Preferably, a coordinate management unit that holds coordinates of the robot when the detection unit detects contact with an obstacle, and a program management unit that holds an interruption position of a program interrupted by the detection unit due to contact with an obstacle. and a program resuming unit for resuming the program interrupted by the stopping unit. A program resumer resumes the program from the interrupted position maintained by the program manager.

Preferably, the forward movement unit returns the locus reversed by the reverse movement unit, and the program restart unit causes coordinates of the robot returning the locus by the forward movement unit to match the coordinates held by the coordinate management unit. If so, restart the program.

Preferably, the robot has a total thrust value of 40 N or less of the thrust generated by the servomotor, the increased thrust by the speed reduction mechanism, and the maximum moment length of the robot housing.

A robot control method according to the present invention comprises the steps of: storing a motion trajectory of a robot; operating the robot; detecting that the operating robot has come into contact with an obstacle; when contact with an obstacle is detected in the detecting step, the robot moves backward from the contact position with the obstacle based on the trajectory stored in the storing step; and stopping the movement of the robot that has reversed by the step of performing.

A program according to the present invention comprises steps of storing a locus of motion of a robot; operating the robot; detecting that the robot operating by the step of operating contacts an obstacle; when contact with an obstacle is detected in the step of moving, the robot moves backward from the contact position with the obstacle based on the trajectory stored in the storing step; and the step of moving backward. and stopping the movement of the robot that has moved in reverse.

ADVANTAGE OF THE INVENTION According to this invention, a robot can be controlled more safely and efficiently.

1 is a diagram illustrating the overall configuration of a robot control system 1; FIG. FIG. 3 is a diagram showing interactions between the SCARA robot 3 and the robot controller 7; 3 is a diagram illustrating a functional configuration of a robot controller 7; FIG. 4 is a sequence diagram of robot control in the robot control system 1 at the time of contact with a human body; FIG. 4 is a flowchart for explaining restart processing (S10) of the SCARA robot 3 in the robot control system 1. FIG.

The safe operation of SCARA collaborative robots has been achieved by limiting the maximum thrust generated by the actuator system, which includes servo motors and reduction gears, within the prescribed values of safety standards. In other words, the safe operation up to now only satisfies the minimum requirement that the robot can stop moving without causing damage to the human body when the worker and the robot come into contact with each other during work. There was no established method for restarting.

A series of procedures (movements) related to the safe operation of conventional collaborative robots consisted of the robot executing a stopping operation upon contact with the human body, the operator of the robot confirming the stopping operation, confirming the safety of the human body, and performing the work. A time-consuming work procedure was required in which the robot's program in the middle was discarded, the robot returned to the robot origin, which is the work start point of the robot, and the next robot operation restart command was waited for. Due to this interruption of work, "home return operation" and "workpiece disposal" are required as a recovery process, which takes time and increases takt time, making it difficult to synchronize operations with other robots in the production line. There was also the possibility that overall takt adjustment would be required.

Specifically, SCARA-type collaborative robots are often installed close to workers because it is essential that workers and robots can work together smoothly. Therefore, in cases where workers may accidentally touch the housing of the robot during collaborative work, the most important specification item is to prevent damage to the human body. The next requirement is how to restart the robot in a short period of time and restore the work interrupted by the contact once contact occurs. The specification of short-time recovery is determined by the handling of the takt during execution in which contact with the robot occurs. That is, conventionally, the takt where contact occurred is discarded, the robot is once returned to the origin position, the workpiece is discarded, the robot is returned to the initial conditions, and then the next new takt is started. When a general robot stops during work, it is assumed that some kind of abnormal situation has occurred, and the robot manager immediately turns off the main power supply and begins investigation work to confirm safety. This work will take some time.

Therefore, in order to solve these problems, the present invention, when a worker comes into contact with a SCARA collaborative robot, causes the robot to stop after performing an evacuation operation, and after restarting, continue the program before stopping. to ensure the safety of the human body, and to provide a robot control system that continues processing without discarding the program of the robot in the middle of work.

FIG. 1 is a diagram illustrating the overall configuration of a robot control system 1. As shown in FIG.
As illustrated in FIG. 1 , the robot control system 1 has a SCARA robot 3 and a robot controller 7 .
The SCARA robot 3 is a multi-joint robot, and the joints are moved by the power of the servomotor 9, the end effector attached to the tip of the arm is moved to the target position, and the object is grasped and moved, welded, etc. I do painting. Each joint has a servo actuator 11 that controls the position and speed of the servo motor 9 . The SCARA robot 3 in this example has four axes: a turning axis, a first horizontal axis, a second horizontal axis, and a vertical vertical axis. The SCARA robot 3 in this example regards a 1.8 degree step hybrid stepping motor as a multi-pole synchronous motor, and a motor with a 200 pulses/revolution encoder arranged on the motor rotation shaft as a brushless servo actuator. Electric motors using a control system that controls each axis were used as actuators for all the constituent axes. The SCARA robot 3 is an example of a robot according to the present invention.

In a normal four-axis SCARA robot, the robot housing is complicatedly deformed because the vertical axis is provided at a location different from the pivot axis, and the deformation reduces the robot work space.
On the other hand, the 4-axis servo actuators 11 of this example are all built in the housing of the SCARA robot 3, and the structure is simple because the up-down vertical axis is provided directly above the turning axis. is.

The robot controller 7 is a control device housing a servo amplifier for controlling the servo motor 9, a substrate, and the like, and comprehensively controls the movement of the SCARA robot 3. FIG. Specifically, the robot controller 7 performs coordinate management, thrust management, etc. of the SCARA robot 3 . Although the robot controller 7 is independent from the SCARA robot 3 in FIG. 1, it may be incorporated in the housing of the SCARA robot 3 directly above the turning axis for miniaturization. The miniaturization enables effective utilization of the working space of the SCARA robot 3 . In addition, the robot controller 7 adopts a visual program based on Japanese Patent No. 4332879, which does not use a conventional program language (including a robot program language), thereby significantly reducing the burden on programming beginners.

FIG. 2 is a diagram showing interaction between the SCARA robot 3 and the robot controller 7. As shown in FIG.
As illustrated in FIG. 2 , the robot controller 7 transmits and receives signals to and from the servo controller 5 and controls the servo motor 9 via the servo controller 5 .
The contact detection unit of the SCARA robot 3 notifies the servo controller 5 and the robot controller 7 of the contact when detecting contact with the obstacle. The servo controller 5 stops each servo motor 9, and the robot controller 7 manages stop coordinates of the stopped robot. When the restart signal is sent by the restart switch, the robot controller 7 notifies the servo controller 5 of the restart, and restarts the interrupted program when the SCARA robot 3 reaches the stop coordinates for the first time after restarting. resume.

FIG. 3 is a diagram illustrating the functional configuration of the robot controller 7. As shown in FIG.
As illustrated in FIG. 3, a robot control program 70 is installed in the robot controller 7 . The robot control program 70 includes a trajectory storage section 700, a forward movement section 702, a stop detection section 704, a reverse movement section 706, a stop section 708, a coordinate management section 710, a program management section 712, a program restart section 714, and a thrust management section 708. have.
The trajectory storage unit 700 stores the trajectory of the operation of the SCARA robot 3 .
The advance unit 702 moves the SCARA robot 3 . Further, when the SCARA robot 3 is restarted, the advance unit 702 sets a movement amount equal to the reversed movement amount in the servo controller 5 based on the trajectory reversed by the reverse movement unit 706 (described later). return to 3.
The stop detection unit 704 detects that the SCARA robot 3 operated by the advancing unit 702 has come into contact with an obstacle. Specifically, when the SCARA robot 3 comes into contact with an obstacle, the contact detection unit of the SCARA robot 3 detects the contact and notifies the stop detection unit 704 of the contact. Also, the stop detection unit 704 interrupts the program that the SCARA robot 3 was executing. Stop detection unit 704 is an example of a detection unit according to the present invention.

When the stop detection unit 704 detects contact with an obstacle, the reverse unit 706 causes the SCARA robot 3 to move backward from the position of contact with the obstacle based on the trajectory stored in the trajectory storage unit 700. Let Specifically, when the stop detection unit 704 detects contact with an obstacle, the reverse unit 706 outputs a movement-use reverse pulse to the servo controller 5, and causes the SCARA robot 3 to move in the direction of contact detection. reverse at a constant distance from As a result, the distance between the obstacle and the SCARA robot 3 is maintained, ensuring safety.
A stop unit 708 stops the operation of the SCARA robot 3 that has been reversed by the reverse unit 706 .
The coordinate management unit 710 holds coordinates of the robot when the stop detection unit 704 detects contact with an obstacle. Specifically, when the stop detection unit 704 detects contact, the coordinate management unit 710 stores all the coordinates of the constituent axes of the SCARA robot 3 in the memory.
The program management unit 712 holds the interruption position of the program interrupted by contact with an obstacle by the stop detection unit 704 .

The program resuming unit 714 resumes the program from the program interruption position held by the program management unit 712 . Specifically, when the coordinates held by the coordinate management unit 710 match the coordinates of the re-operated SCARA robot 3, the program restart unit 714 restarts the program from the interrupted position held by the program management unit 712. to resume. More specifically, the program resuming unit 714 resumes the program when the coordinates of the robot returning on the backward trajectory by the advancing unit 702 match the coordinates held by the coordinate managing unit 712 . That is, when the restarted SCARA robot 3 passes the stop coordinates managed by the coordinate management unit 710, the program restarting unit 714 switches to the remaining program after contact stop. This allows the robot to complete one sequence with minimal lost time.
The thrust management unit 716 controls the thrust of the arm of the SCARA robot 3, and the maximum thrust of the servo actuator 11 is 40N or less. Specifically, the thrust management unit 716 controls the total thrust value of the thrust generated by the servomotor 9, the increased thrust by the speed reduction mechanism, and the maximum moment length of the SCARA robot 3 housing to be 40N or less. That is, in this example, the maximum thrust generated by each of the four-axis servo actuators is 40 N or less. As a result, the SCARA robot 3 can be balanced with a force of 40N when it comes into contact with the human body or the external moving object, and can stop without being damaged by the human body or the external moving object.

FIG. 4 is a sequence diagram of robot control at the time of contact with the human body in the robot control system 1. As shown in FIG.
As illustrated in FIG. 4, the SCARA robot 3 decelerates and stops the movement of the SCARA robot 3 when contact with an obstacle is detected. Subsequently, the SCARA robot 3 is reversed by a predetermined movement amount and stopped. After that, the operator of the SCARA robot 3 confirms safety, presses the restart switch of the SCARA robot 3, and the program is resumed from the interrupted position of the interrupted program.

FIG. 5 is a flowchart for explaining the stop processing (S10) of the SCARA robot 3 in the robot control system 1. As shown in FIG.
As illustrated in FIG. 5, in step 100 (S100), the SCARA robot 3 is operated by the advancing section 702 to perform work. The trajectory storage unit 700 stores the trajectory of the operation of the SCARA robot 3 by the advancing unit 702 .
At step 105 (S105), the contact detection unit of the SCARA robot 3 detects contact with an obstacle and notifies the stop detection unit 704 of the robot controller 7 of the contact. The stop detection unit 704 notifies the stop unit 708 of detection of contact.
At step 110 ( S<b>110 ), the contact detection unit of the SCARA robot 3 stops the servo motor 9 via the servo controller 5 . In addition, the stop detection unit 704 interrupts the program being executed, and the program management unit 712 stores the interrupt position of the program. Furthermore, the coordinate management unit 710 holds stop coordinates of the SCARA robot 3 .

At step 115 ( S<b>115 ), the reversing unit 706 causes the SCARA robot 3 to move backward from the position where it stopped based on the trajectory stored by the trajectory storage unit 700 by a minute distance. When the obstacle is a human body, the SCARA robot 3 moves backward from the position of contact with the human body by a predetermined amount of movement, thereby moving away from the human body and ensuring safety.
At step 120 (S120), the stopping unit 708 stops the SCARA robot 3 that has moved in reverse again.
At step 125 (S125), the operator of the SCARA robot 3 confirms that there is no human body or external moving object within the movement trajectory of the SCARA robot 3, and presses the restart switch to restart the SCARA robot 3. Press The robot controller 7 proceeds to S130 when the depression of the restart switch is detected, and waits when the depression is not detected.
At step 130 (S130), the advancing section 702 advances the SCARA robot 3 on the reversed trajectory. The program management unit 712 determines whether or not the stop coordinates of the SCARA robot 3 held by the coordinate management unit 710 match the coordinates of the re-operated SCARA robot 3 . If they match, the process proceeds to S135. If they do not match, wait to restart the program until they match.
At step 135 (S135), the program resuming section 714 resumes the program from the program interruption position managed by the program management section.

In the robot control system 1, because the SCARA robot 3 stops due to contact with a human body or an external relic, even if the robot stops safely, an obstacle (a human body or an external relic) within the robot operation trajectory immediately after that. It is possible to confirm whether or not it has been removed safely, and if safety is confirmed, it is possible to re-execute the remaining processes of the current takt where a stop occurred immediately after contact, and the process is interrupted for a short time. Since the reason for the stoppage is clear, there is no problem in continuing the process. Therefore, even if a stop operation occurs, the process is not abandoned, and there is an advantage that handling at the site is simple because the stop only for a very short time does not affect other processes.

As described above, the robot control system 1 causes the SCARA robot 3 to instantly execute a retraction operation in a minute section from the point at which the SCARA robot 3 stops contact, and immediately after the retraction operation, safety is confirmed and the robot is restarted. This minimizes the time required for the safe stop operation without causing further damage to the obstacles it touches. Furthermore, when the restarted SCARA robot 3 first passes through the contact stop point, the rest of the program before the stop is run to enable recovery in a short period of time (in the category of momentary stoppage).

REFERENCE SIGNS LIST 1 robot control system 3 SCARA robot 5 servo controller 7 robot controller 9 servo motor 11 servo actuator

Claims (4)

a trajectory storage unit that stores the trajectory of the motion of the robot;
a forwarding unit that operates the robot;
a detection unit that detects that the robot operated by the advancing unit has come into contact with an obstacle;
a reversing unit that, when the detection unit detects contact with an obstacle, causes the robot to move backward by a minute distance from the position of contact with the obstacle based on the trajectory stored in the trajectory storage unit; ,
a stopping unit that stops the movement of the robot that has traveled in reverse by the reversing unit;
a coordinate management unit that holds coordinates of the robot when contact with an obstacle is detected by the detection unit;
a program management unit that holds an interrupted position of a program interrupted by contact with an obstacle by the detection unit;
a program restart unit for restarting the program interrupted by the detection unit ;
The forward movement unit returns the trajectory traveled backward by the reverse movement unit, and the program restart unit, when the coordinates of the robot returning the trajectory by the forward movement unit match the coordinates held by the coordinate management unit, A robot control system that resumes the program from the interrupted position maintained by the program manager. 2. The robot control system according to claim 1, wherein the robot has a total thrust value of 40 N or less of the thrust generated by the servomotor, the increased thrust by the speed reduction mechanism, and the maximum moment length of the robot housing. a step of storing the trajectory of the motion of the robot;
operating the robot;
detecting that the robot, which is operated by the operating step, has come into contact with an obstacle;
when contact with an obstacle is detected in the detecting step, the robot moves backward by a minute distance from the position of contact with the obstacle based on the trajectory stored in the storing step;
stopping the movement of the robot that has moved backward by the step of moving backward;
a step of holding coordinates of the robot when contact with an obstacle is detected by the detecting step;
a step of holding an interrupted position of a program interrupted by contact with an obstacle in the detecting step;
resuming the program interrupted by the detecting step;
In the operating step, the robot returns to the trajectory reversed by the reversing step, and in the resuming step, the coordinates of the robot returning to the trajectory by the operating step and the coordinates are held by the step of holding the coordinates. and restarting the program from the interrupted position held by the step of holding the interrupted position when the coordinates coincide with the coordinates obtained. a step of storing the trajectory of the motion of the robot;
operating the robot;
detecting that the robot, which is operated by the operating step, has come into contact with an obstacle;
when contact with an obstacle is detected in the detecting step, the robot moves backward by a minute distance from the position of contact with the obstacle based on the trajectory stored in the storing step;
stopping the movement of the robot that has moved backward by the step of moving backward;
a step of holding coordinates of the robot when contact with an obstacle is detected by the detecting step;
a step of holding an interrupted position of a program interrupted by contact with an obstacle in the detecting step;
resuming the program interrupted by the detecting step; and
In the operating step, the robot returns to the trajectory reversed by the reversing step, and in the resuming step, the coordinates of the robot returning to the trajectory by the operating step and the coordinates are held by the step of holding the coordinates. restarting the program from the interrupted position held by the step of holding the interrupted position, if the coordinates match.

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