TWI684502B - Method for releasing the brake of a robot arm - Google Patents

Abstract

A method for releasing the brake of a robot arm is disclosed. The robot arm rotates a motor with a predetermined rotation direction and rotation angle when releasing the brake to withdraw the pin of an electromagnetic valve. If releasing the brake is fail, the motor is rotated with an opposite rotation direction and the rotation angle to ensure the success of releasing the brake.

Description

How to release the brake on the robot arm (1)

The invention relates to a robot arm, in particular to a method for releasing the brake and allowing the robot arm to move when the robot arm stops rotating from the brake.

Factory automation uses robotic arms to automatically grab workpieces and continuously move back and forth for assembly and manufacturing to improve production efficiency. In addition to the drive module to provide power, the robot arm that moves back and forth still needs to rely on stable and reliable brakes to stop the robot arm at a predetermined position for precise operation.

Please refer to FIG. 1, which is the driving module 10 of the robot arm of the prior art US Patent US8410732. The drive module 10 of the prior art uses the motor 11 to drive the rotating shaft 12 to rotate, and is decelerated by the deceleration device 13 to output power to move the robot arm. The driving module 10 is provided with a braking device. The braking device fixes the ratchet 14 on the rotating shaft 12 and a solenoid valve 15 is provided around the ratchet 14. The solenoid valve 15 is engaged with the ratchet 14 by a telescopic stop pin 16 to block or release the rotation of the ratchet 14. . The driving module 10 further fixes an encoder 17 at one end of the rotating shaft 12 to detect the rotation angle of the motor 11 as a feedback signal for monitoring and controlling the rotation of the motor 11.

When the robot arm needs to move, the solenoid valve 15 is controlled to retract the stop pin 16 to release the ratchet wheel 14, and then the motor 11 is driven by the signal to drive the rotating shaft 12 to rotate, and the encoder 17 monitors whether the motor 11 rotates according to the angle required by the signal. When the robot arm needs to stop, the drive module 10 brakes In operation, the solenoid valve 15 is activated to extend the stop pin 16 to block the rotation of the ratchet wheel 14 and generate a braking torque to resist the inertial force of the load formed by the robot arm itself and the loaded workpiece to stop the rotation of the rotating shaft 12 fixed by the ratchet wheel 14 to prevent the robot arm from moving. Then, the encoder 17 monitors whether the motor 11 stops at a required angle according to the signal.

However, when the stop pin 16 of the solenoid valve 15 stops the rotation of the robot arm, the load of the robot arm will act on the stop pin 16 of the solenoid valve 15 via the ratchet 14. If the workpiece is too large, the load will cause the ratchet 14 and the stop A large frictional force is formed between the pins 16. When the robot arm needs to move again, the force of the control solenoid valve 15 to retract the stop pin 16 is not enough to overcome the friction between the ratchet wheel 14 and the stop pin 16, the stop pin 16 is blocked by the ratchet wheel 14 and the solenoid valve 15 will not be able to run smoothly Retracting the stop pin 16 releases the ratchet 14, thus causing the drive module 10 to fail to release the brake. If the brake module cannot be released, once the driving module 10 uses a greater force or rotation angle to drive the motor 11 to rotate, it will cause the stop pin 16 or the ratchet 14 to bend and deform, which not only affects the accuracy of the positioning of the robot arm, but also damages the robot arm. . Therefore, there are still problems that need to be solved urgently for the robot arm to release the brake.

The purpose of the present invention is to provide a method for the robot arm to release the brake. By presetting a smaller rotation angle of the motor, the motor is controlled to rotate in different rotation directions, so that the load-transmitting ratchet wheel leaves the stop pin to retract the stop pin to release the brake.

In order to achieve the purpose of the foregoing invention, the method for releasing the brake of the robot arm according to the first embodiment of the present invention, when releasing the brake, presets the rotation angle for controlling the rotation of the motor, rotates the motor with the preset first rotation direction and rotation angle, and releases the brake Retract the stop pin of the solenoid valve. If the brake is successfully released, the brake release operation ends. If the brake fails to be released, rotate the motor with the preset second rotation direction and rotation angle, and release the brake to retract the stop pin of the solenoid valve, such as Successfully released the brake, End the brake release operation.

The release brake of the robot arm of the present invention retracts the stop pin of the solenoid valve, so that the stop pin is separated from the rotation path of the ratchet wheel. The first rotation direction and the second rotation direction are opposite rotation directions. The preset rotation angle is a small angle, so that the stop pin and the ratchet are in a safe elastic deformation. In addition, the encoder monitors the feedback signal of the rotation of the motor shaft, checking that the brake has not been released when it has not been turned to the preset rotation angle, and that the brake has been successfully released when the rotation has been checked to the preset rotation angle.

In the method for releasing a brake of a robot arm in a second embodiment of the present invention, when starting to release a brake, the first rotation direction, the second rotation direction and the rotation angle of the motor rotation are set, and the motor is rotated at the first rotation direction and the rotation angle continuously The motor rotates the motor in the reversed second rotation direction and rotation angle to release the brake for a preset period of time, and finally ends the operation of releasing the brake.

20‧‧‧spindle

21‧‧‧ratchet

22‧‧‧Solenoid valve

23‧‧‧block

FIG. 1 is a side sectional view of the driving module of the prior art robot arm.

FIG. 2 is a schematic diagram of the robot arm of the present invention releasing the brake in the first rotation direction.

FIG. 3 is a schematic diagram of the robot arm of the present invention releasing the brake in the second rotation direction.

4 is a flowchart of a method for releasing a brake by a robot arm according to a first embodiment of the present invention.

FIG. 5 is a schematic diagram of the robot arm of the present invention releasing brakes in two rotation directions.

6 is a flowchart of a method for releasing a brake of a robot arm according to a second embodiment of the invention.

Regarding the technical means adopted by the present invention to achieve the above-mentioned objectives, and their effects, the preferred embodiments are described below with reference to the drawings.

Please refer to FIG. 2 and FIG. 3 at the same time. FIG. 2 is the first rotation side of the robot arm of the present invention 3 is a schematic diagram of the robot arm of the present invention in the second rotation direction to release the brake. The motor of the robot arm of the present invention has a rotating shaft 20, and the brake device sets the ratchet wheel 21 on the circumference of the rotating shaft 20, and the ratchet wheel 21 extends radially from the circumference of the rotating shaft 20. The periphery of the ratchet wheel 21 is provided with a solenoid valve 22. The solenoid valve 22 has a telescopic stop pin 23. The stop pin 23 is subjected to the magnetic force of the solenoid valve 22. When the stop pin 23 is extended, it enters the rotation path of the ratchet wheel 21, and when the stop pin 23 is retracted Disengage the rotation path of the ratchet 21.

When the robot arm brakes, the solenoid valve 22 is controlled to extend the stop pin 23, so that the stop pin 23 enters the rotation path of the ratchet wheel 21 to block the movement of the ratchet wheel 21, generating a braking torque, resisting the inertial force generated by the load L of the robot arm, and stopping the fixed ratchet wheel 21 The rotating shaft 20 rotates, thereby preventing the robot arm from moving. After stopping the rotation of the robot arm, the load L of the robot arm acts on the stop pin 23 of the solenoid valve 22 via the ratchet 21. When the robot arm needs to move again, the brake must be released first. When the brake is released, the solenoid valve 22 is controlled to retract the stop pin 23, so that the stop pin 23 is separated from the rotation path of the ratchet wheel 21, and the rotation of the ratchet wheel 21 is not blocked, so that the motor can freely rotate the rotation shaft 20.

Since the load L of the robot arm changes with the size of the gripping workpiece, and the direction of the load L also changes according to the position where the arm stays, not only can the size and the direction of the load L not be known when the brake is released, but even if the solenoid valve 22 is controlled Retracting the stop pin 23 also cannot ensure whether the friction force can be overcome and the stop pin 23 is successfully retracted. Therefore, in FIG. 2, the present invention first presets the first rotation direction R1 of the motor rotation, the second rotation direction R2, and the rotation angle θ. The preset first rotation direction R1 may be clockwise rotation or counterclockwise rotation. The second rotation direction R2 is opposite to the first rotation direction R1. And the rotation angle θ is small, even if the stop pin 23 blocks the wrong rotation of the ratchet 21, the stop pin 23 and the ratchet 21 are still in a safe elastic deformation.

When the brake is released, the present invention rotates the motor with the preset first rotation direction R1 and the rotation angle θ. In this embodiment, the first rotation direction R1 is taken as an example of counterclockwise rotation, and the control is performed. 制 Solenoid valve 22 retracts the stop pin 23. Because the preset rotation direction is wrong, the first rotation direction R1 drives the rotating shaft 20 to drive the ratchet 21, which is blocked by the stop pin 23. The ratchet 21 presses the stop pin 23 of the fixed solenoid valve 22 and cannot rotate to the preset rotation angle θ And allow the ratchet wheel 21 and the stop pin 23 to elastically deform (as indicated by the dotted line). Under squeezing, the friction between the ratchet wheel 21 and the stop pin 23 is greater, the force of the ratchet wheel 21 blocking the stop pin 23 is stronger, and the solenoid valve 22 cannot be smoothly retracted to the stop pin 23 by the encoder (please refer to FIG. 1) The feedback signal that the rotating shaft 20 is not rotated to the preset rotation angle θ is monitored, and it is checked that the stop pin 23 is not retracted, and it is judged that the brake release fails.

In FIG. 3, under the failure to release the brake in the first rotation direction, the present invention immediately rotates the motor with the preset second rotation direction R2 and the rotation angle θ. This embodiment uses the second rotation direction R2 as a clockwise rotation for illustration. And control the solenoid valve 22 to retract the stop pin 23. Since the rotation shaft 20 drives the ratchet wheel 21 in the second rotation direction R2, and is not blocked by the stop pin 23 of the solenoid valve 22, the rotation shaft 20 smoothly rotates to the rotation angle θ, allowing the ratchet wheel 21 to leave the stop pin 23 (as shown by the broken line). When the stop pin 23 is not under the load L, the ratchet wheel 21 will not catch the stop pin 23, the solenoid valve 22 can smoothly retract the stop pin 23, and the feedback signal of the rotation shaft 20 to the rotation angle θ is monitored by the encoder to check the stop Pin 23 has been retracted and it is judged that the brake was successfully released. Since the direction of rotation is only clockwise and counterclockwise, in the first and second directions of rotation R1 and R2 of the present invention, there must be a direction of rotation that allows the ratchet wheel 21 to leave the stop pin 23, which ensures Successfully lifted the brake.

As shown in FIG. 4, it is a flowchart of a method for releasing a brake of a robot arm according to a first embodiment of the present invention. The detailed steps of the method for releasing the brake of the robot arm of the present invention are described as follows: Step S1 starts to release the brake; at step S2, the present invention sets the first rotation direction, the second rotation direction, and the rotation angle of the motor rotation; step S3, to The first rotation direction is the preset motor rotation direction; step S4, the motor is rotated with the preset rotation direction and rotation angle; step S5, and the brake is released, Control the solenoid valve to retract the stop pin; Step S6, check whether the brake is released successfully? If the brake release fails, that is, the control solenoid valve cannot retract the stop pin, then go to step S7, change the preset second rotation direction to the motor rotation direction, return to step S4, and continue to rotate the motor at the preset rotation direction and rotation angle. Step S6 If the brake release is successful, that is, the control solenoid valve is smoothly retracted to the stop pin, then step S8 is entered to end the brake release operation.

As shown in FIG. 5, it is a schematic diagram of the robot arm of the present invention releasing brakes in two consecutive rotation directions. It can be known from the foregoing embodiment that the ratchet wheel 21 will leave the stop pin 23 or reduce the friction of the stop pin 23 in one of the first rotation direction or the second rotation direction, so that the solenoid valve 22 smoothly retracts to the stop pin 23 to release the brake. Therefore, the present invention can also use the set rotation angle θ and continuous different rotation directions R to control the motor to rotate the rotating shaft 20 back and forth, so that the inertia of the robot arm generates jitters when the robot arm swings back and forth, driving the ratchet wheel 21 away from the stop pin 23 or reducing the gear Friction of pin 23. The present invention also controls the solenoid valve 22 to continue to release the brake during the jitter, so that the solenoid valve 22 smoothly retracts the stop pin 23 during the jitter to successfully release the brake, thereby simplifying the operation of checking whether the stop pin 23 is retracted in the foregoing embodiment time. Similarly, in the present invention, before the motor is controlled to rotate the rotating shaft 20 back and forth, the solenoid valve 22 is controlled to continuously release the brake for a period of time, and the brake is released when the motor rotates the robot arm to and fro while swinging back and forth.

As shown in FIG. 6, it is a flowchart of a method for releasing a brake of a robot arm according to a second embodiment of the present invention. The detailed steps of the method for releasing the brake of the robot arm in the second embodiment of the present invention are described as follows: Step T1 starts to release the brake; at step T2, the present invention sets the first rotation direction, the second rotation direction and the rotation angle of the motor rotation; steps T3, rotate the motor in the first rotation direction and rotation angle; Step T4, continuously rotate the motor in the reverse second rotation direction and rotation angle; Step T5, preset to continue to release the brake for a certain period of time; enter step T6, end the brake release operation .

Therefore, the method for releasing the brake of the robot arm of the present invention can control the motor to rotate the preset rotation angle in different rotation directions sequentially or continuously by setting a smaller rotation angle, and let the ratchet wheel in one of the rotation directions or jitter Leave the stop pin, and control the solenoid valve to retract the stop pin to avoid the ratchet card blocking pin, so that the solenoid valve is smoothly retracted to achieve the purpose of successfully releasing the brake.

The above are only for the convenience of describing the preferred embodiments of the present invention, and the scope of the present invention is not limited to these preferred embodiments. Any changes made according to the present invention without departing from the spirit of the present invention , All belong to the scope of patent application of the present invention.

20‧‧‧spindle

21‧‧‧ratchet

22‧‧‧Solenoid valve

23‧‧‧block

Claims (3)

A method for releasing a brake of a robot arm, the steps include: starting to release the brake; setting the first rotation direction, the second rotation direction and the rotation angle of the motor rotation; rotating the motor with the first rotation direction and the rotation angle; continuously rotating with the second rotation Rotate the motor in the direction and rotation angle; release the brake; end the release operation. The method for releasing a brake of a robot arm as described in item 1 of the patent application scope, wherein the first rotation direction and the second rotation direction are opposite rotation directions. The method for releasing a brake of a robot arm as described in item 1 of the patent application scope, wherein the release of the brake lasts for a preset period of time.

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