A robot brake detection method

Abstract

The application relates to the field of failure analysis, in particular to a robot brake detection method, and the specific steps are as follows: S0: calculating a torque adjustment step; S1: calculating an adjustment period; S3: closing a torque feedback; S4: moving a robot; S5: recording T0; S6: closing a brake; S7: increasing a feedforward torque; S8: recording data; S9: reducing the feedforward torque; S10: recording data; S11: calculating; S12: exiting detection; the application does not need to additionally install a torque sensor during detection, can obtain torque information in real time through motor feedback, reduces cost and simplifies structure; the robot keeps a static state during detection, so compared with detection in a motion process, the possibility of damage is reduced; the application detects the performance of the robot brake by controlling the feedforward torque, makes the brake work in the detection process, continuously increases the feedforward torque, but due to the existence of the feedback torque, the brake will not bear an excessively large torque, so the performance of the brake is effectively protected.

Description

Technical Field

[0001] This invention relates to the field of failure analysis, specifically a method for detecting robot brakes. Background Technology

[0002] Prolonged use of a robot or damage to its motor, such as a broken oil seal, can weaken the braking capacity of the motor brakes. This not only affects the stopping distance during emergency stops but can also lead to serious problems, such as the robot arm falling due to insufficient braking capacity to maintain the robot's own weight. Therefore, it is necessary to regularly check the braking capacity of each brake on the robot. When the braking capacity is insufficient to decelerate and stop the robot or maintain its own weight, the user should be promptly reminded to replace the brakes.

[0003] To detect brake malfunctions in advance, CN102150023A discloses a method for detecting robot brakes. This method requires installing a torque sensor inside the robot. The robot is first moved in a predetermined state, then the brake is activated and the motor is turned off, so that the motor no longer generates torque. Data is collected by the torque sensor during this operating state, and the brake's condition is determined by analyzing the collected torque data. However, this torque sensor-based detection scheme requires installing a torque sensor at each joint, increasing costs and necessitating the design of a complex mechanical system, making repair difficult after damage.

[0004] CN107298088B discloses a brake inspection method. This method first measures the load torque applied to the motor while the brake is engaged; then, after the brake is disengaged, the load torque applied to the motor is measured again. Finally, based on the load torques measured in the two methods, the ratio of the load torques is calculated, and the calculated ratio is compared with a set threshold to determine the brake's state. This detection method, which checks the brake during robot movement or continuously increases the drive torque after the brake is engaged until the robot moves, increases brake wear, the likelihood of damage, and reduces its lifespan, posing a safety hazard.

[0005] CN105651499A relates to a brake diagnostic device, brake diagnostic method, and brake diagnostic system for diagnosing the brakes of motors in industrial robots. The device comprises: a brake control unit that activates or deactivates the brake; and a diagnostic unit that diagnoses whether an abnormality exists in the brake during operation. This invention enables the diagnosis of brakes in motors.

[0006] CN107073712B discloses a method and apparatus for evaluating static braking torque in a robot, relating to a method, apparatus, and computer program product for evaluating the static braking torque of a robot joint brake, as well as a robot arrangement including such an apparatus. The braking torque evaluation apparatus includes a torque evaluation unit that first disables any integral control portion of the robot controller, activates the brake, obtains at least one braking test position of the joint, provides a position command to the robot controller after brake activation to command the joint to move to a target position, obtains joint position measurements after providing the position command, and uses the position command and joint position measurements to determine whether the static braking torque of the brake meets or fails to meet the static braking torque requirement. Both of the above methods require calculating a suitable desired position during the detection process, making the process relatively cumbersome. Furthermore, the process may involve situations where the motor moves while the brake is in operation, which could accelerate brake damage.

[0007] Existing testing methods mostly have certain limitations. Their design structures are relatively complex and can damage the brake. Therefore, there is a need to design a simple and non-damaging brake testing method. Summary of the Invention

[0008] To address the aforementioned problems, this invention proposes a method for detecting robot brakes.

[0009] A method for detecting robot brakes, the specific steps of which are as follows:

[0010] S0: Calculate the torque adjustment step size: Set the torque adjustment speed during the brake detection process to P*Tn / s, where Tn is the rated torque of the motor and P is the proportional coefficient, set to 0.5, which means that it takes 1 / 0.5 = 2s to increase the torque value from zero to the rated torque. Then calculate the torque adjustment step size.

[0011] S1: Calculate the torque adjustment cycle: Calculate the number of adjustment cycles required for the brake torque to increase from zero to the braking torque during the brake detection process, N = ceil(Tb / (P*Tn));

[0012] S3: Turn off torque feedback: Turn off the torque feedforward function before performing brake detection, and set the feedforward torque to 0. In this way, the feedforward torque will not affect the robot's actual torque output.

[0013] S4: Mobile Robot: Move the robot to the position where the brake detection is performed. This position should not affect the operation. Maintain the robot in this position for 2 seconds.

[0014] S5: Record T0: Record the actual torque value T0 at this time, and check whether the current actual torque value exceeds the rated torque;

[0015] S6: Close the brake: At this time, the motor remains stationary, and the current position of the motor Q0 is recorded;

[0016] S7: Increase feedforward torque: Increase the feedforward torque according to the given step size Ts for N cycles. After completion, the feedforward torque value will be equal to or slightly greater than the theoretical braking torque.

[0017] S8: Record position: After maintaining for 1 second, record the actual torque value T1 and the current motor position Q1;

[0018] S9: Reduce feedforward torque: Reduce the feedforward torque by a given step size Ts for 2*N cycles. After completion, the feedforward torque value is equal to or slightly less than the opposite of the theoretical braking torque.

[0019] S10: Record data: After maintaining for 1 second, record the actual torque value T2 and the current motor position Q2. If abs(Q2-Q0)>ε, it indicates that the brake is damaged and brake detection cannot be performed.

[0020] S11: Calculation: The actual braking torque T is calculated as shown in the following formula:

[0021] T = min(T1 - T0, T0 - T2)

[0022] S12: Exit detection: After the calculation is completed, set the feedforward torque to 0, open the brake, and exit the brake detection process.

[0023] Step S0 involves calculating the torque adjustment step size for a single cycle as Ts = S * P * Tn based on the communication cycle S between the controller and the driver.

[0024] In step S1, Tb is the braking torque value, and the ceil() function represents rounding up.

[0025] In step S4, the robot needs to maintain a distance of more than 200mm from the surrounding equipment when it moves to the position to perform brake detection.

[0026] In step S5, if abs(T0) > Tn, where the abs() function represents the absolute value, the detection is stopped, and the user is prompted that the robot is in contact with surrounding equipment at the current position, and the brake detection cannot be performed. Please readjust the position.

[0027] In step S8, if abs(Q1-Q0)>ε, where ε is the allowable change in motor position, which can be set to 0.5 degrees, then it indicates that the brake is damaged and brake detection cannot be performed.

[0028] The beneficial effects of this invention are: This invention eliminates the need for an additional torque sensor during detection, allowing for real-time acquisition of torque information via motor feedback, thus reducing costs and simplifying the structure; This invention keeps the robot stationary during detection, reducing the likelihood of damage compared to detection during movement; This invention detects the robot's brake performance by controlling the feedforward torque, activating the brake during detection and continuously increasing the feedforward torque, but the presence of feedback torque prevents the brake from being subjected to excessive torque, effectively protecting the brake's performance. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0030] Figure 1 This is a block diagram of the brake detection system of the present invention;

[0031] Figure 2 This is a flowchart of the brake testing process of the present invention;

[0032] Reference numerals in the attached diagram: 1. Brake detection module; 2. Position controller; 3. Feedforward torque controller; 4. Brake switch controller; 5. First adder; 6. Drive position controller; 7. Second adder; 8. Drive speed controller; 9. Third adder; 10. Drive torque control loop; 11. Motor; 12. Brake; 13. Torque sensor; 14. Speed ​​sensor; 15. Position sensor. Detailed Implementation

[0033] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below.

[0034] like Figures 1 to 2 As shown, a robot brake detection fixture includes a brake detection module 1 capable of acquiring the actual position and torque of the motor in real time. The brake detection module 1 includes a position controller 2 for controlling the command position, a feedforward torque controller 3 for controlling the feedforward torque before and after brake detection, and a brake switch controller 4 for controlling the closing and opening of the brake 12.

[0035] This invention eliminates the need for an additional torque sensor during detection, allowing torque information to be obtained in real time via feedback from the motor 11, thus reducing costs and simplifying the structure. Furthermore, this invention keeps the robot stationary during detection, reducing the likelihood of damage compared to detection during movement. By controlling the feedforward torque to detect the robot's brake performance, the invention activates the brake during detection, continuously increasing the feedforward torque. However, the presence of the feedback torque prevents the brake from being subjected to excessive torque, effectively protecting its performance.

[0036] The position control loop includes a position control loop, a speed control loop, and a torque control loop. The position control loop includes a first adder 5 and a drive position controller 6. The speed control loop includes a second adder 7 and a drive speed controller 8. The torque control loop includes a third adder 9 and a drive torque control loop 10.

[0037] The drive torque control loop 10 is connected to a motor 11 via a wiring harness. The motor 11 is equipped with a brake 12, a torque sensor 13, a speed sensor 14, and a position sensor 15. The brake 12 detects when and where to start by controlling the brake detection through a provided brake detection command. The user can add the brake detection command in the program at a suitable location that is a certain distance from surrounding equipment and does not affect normal operation.

[0038] The speed can be obtained by differentially analyzing the data obtained from the position sensor 15, which can replace the speed sensor 14.

[0039] The first adder 5, the second adder 7, and the third adder 9 constitute a driver, which is used to receive the command position sent by the position controller 2 and the actual position fed back by the position sensor 15. The command position and the actual position are superimposed by the first adder 5 and used as the input to drive the position controller 6.

[0040] After the drive position controller 6 calculates the command speed and the actual speed obtained from the speed sensor 14, the command torque is obtained by the second adder 7. The command torque, the feedforward torque output by the controller feedforward torque controller 3 and the actual torque obtained by the torque sensor 13 are calculated by the third adder 9 to obtain the resultant torque, which is input to the drive torque control loop 10. The current is calculated by the drive torque control loop 10 and input to the motor 11.

[0041] A method for detecting robot brakes, the specific steps of which are as follows:

[0042] S0: Calculate the torque adjustment step size: Set the torque adjustment speed during the brake detection process to P*Tn / s, where Tn is the rated torque of the motor and P is the proportional coefficient, set to 0.5, which means that it takes 1 / 0.5 = 2s to increase the torque value from zero to the rated torque. Then calculate the torque adjustment step size.

[0043] S1: Calculate the torque adjustment cycle: Calculate the number of adjustment cycles required for the brake torque to increase from zero to the braking torque during the brake detection process, N = ceil(Tb / (P*Tn));

[0044] S3: Turn off torque feedback: Turn off the torque feedforward function before performing brake detection, and set the feedforward torque to 0. In this way, the feedforward torque will not affect the robot's actual torque output.

[0045] S4: Mobile Robot: Move the robot to the position where the brake detection is performed. This position should not affect the operation. Maintain the robot in this position for 2 seconds.

[0046] S5: Record T0: Record the actual torque value T0 at this time, and check whether the current actual torque value exceeds the rated torque;

[0047] S6: Close the brake: At this time, the motor remains stationary, and the current position of the motor Q0 is recorded;

[0048] S7: Increase feedforward torque: Increase the feedforward torque according to the given step size Ts for N cycles. After completion, the feedforward torque value will be equal to or slightly greater than the theoretical braking torque.

[0049] S8: Record data: After maintaining for 1 second, record the actual torque value T1 and the current motor position Q1;

[0050] S9: Reduce feedforward torque: Reduce the feedforward torque by a given step size Ts for 2*N cycles. After completion, the feedforward torque value is equal to or slightly less than the opposite of the theoretical braking torque.

[0051] S10: Record data: After maintaining for 1 second, record the actual torque value T2 and the current motor position Q2;

[0052] S11: Calculation: The actual braking torque T is calculated as shown in the following formula:

[0053] T = min(T1 - T0, T0 - T2)

[0054] S12: Exit detection: After the calculation is completed, set the feedforward torque to 0, open the brake, and exit the brake detection process.

[0055] Step S0 involves calculating the torque adjustment step size for a single cycle as Ts = S * P * Tn based on the communication cycle S between the controller and the driver.

[0056] In step S1, Tb is the braking torque value, and the ceil() function represents rounding up.

[0057] In step S4, the robot needs to maintain a distance of more than 200mm from the surrounding equipment when it moves to the position to perform brake detection.

[0058] In step S5, if abs(T0) > Tn, where the abs() function represents the absolute value, the detection is stopped, and the user is prompted that the robot is in contact with surrounding equipment at the current position, and the brake detection cannot be performed. Please readjust the position.

[0059] In step S8, if abs(Q1-Q0)>ε, where ε is the allowable change in motor position, which can be set to 0.5 degrees, it indicates that the brake is damaged and brake detection cannot be performed. This is because the driver is working in position control mode. If the brake 12 has a lower capacity than the theoretical value, the motor 11 will move slightly when the feedforward torque is large, resulting in a position following error. Under the action of the feedback loop, the feedback torque will be automatically adjusted so that the sum of the feedforward torque and the feedforward torque no longer continues to increase.

[0060] In step S10, if abs(Q2-Q0)>ε, it indicates that the brake is damaged, that is, the actual braking torque is less than the theoretical braking torque, which means that the brake 12 has reduced capacity or is damaged and cannot perform brake detection.

[0061] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely prisms of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for detecting robot brakes, characterized in that: The specific steps are as follows: S0: Calculate the torque adjustment step size: Set the torque adjustment speed during the brake detection process to P*Tn / s, where Tn is the rated torque of the motor and P is the proportional coefficient, set to 0.5, which means that it takes 1 / 0.5=2s to increase the torque value from zero to the rated torque. Then calculate the torque adjustment step size. S1: Calculate the adjustment cycle: Calculate the number of adjustment cycles required for the brake torque to increase from zero during the brake detection process, N=ceil(Tb / (P*Tn)), where Tb is the brake torque value, and the ceil() function represents rounding up; S3: Turn off torque feedback: Turn off the torque feedforward function before performing brake detection, and set the feedforward torque to 0. In this way, the feedforward torque will not affect the robot's actual torque output. S4: Mobile Robot: Move the robot to the position where the brake detection is performed. This position should not affect the operation. Maintain a stationary state in this position for 2 seconds. S5: Record T0: Record the actual torque value T0 at this time, and check whether the current actual torque value exceeds the rated torque; S6: Close the brake: At this time, the motor remains stationary, and the current position of the motor Q0 is recorded; S7: Increase feedforward torque: Increase the feedforward torque according to the given step size Ts for N cycles. After completion, the feedforward torque value will be equal to or slightly greater than the theoretical braking torque. S8: Record data: After maintaining for 1 second, record the actual torque value T1 and the current motor position Q1; S9: Reduce feedforward torque: Reduce the feedforward torque by a given step size Ts for 2*N cycles. After completion, the feedforward torque value is equal to or slightly less than the opposite of the theoretical braking torque. S10: Record data: After maintaining for 1 second, record the actual torque value T2 and the current motor position Q2; S11: Calculation: The actual braking torque T is calculated as shown in the following formula: T = min(T1 - T0, T0 - T2) S12: Exit detection: After the calculation is completed, set the feedforward torque to 0, open the brake, and exit the brake detection process.

2. The robot brake detection method according to claim 1, characterized in that: Step S0 involves calculating the torque adjustment step size for a single cycle as Ts = S * P * Tn based on the communication cycle S between the controller and the driver.

3. The robot brake detection method according to claim 1, characterized in that: In step S4, the robot needs to maintain a distance of more than 200mm from the surrounding equipment when it moves to the position to perform brake detection.

4. The robot brake detection method according to claim 1, characterized in that: In step S5, if abs(T0) > Tn, where the abs() function represents the absolute value, the detection is stopped, and the user is prompted that the robot is in contact with the surrounding equipment at the current position, and the brake detection cannot be performed. Please readjust the position.

5. The robot brake detection method according to claim 1, characterized in that: In step S8, if abs(Q1-Q0)>ℇ, where ℇ is the allowable change in motor position and the abs() function represents the absolute value, then the brake is damaged and brake detection cannot be performed.

6. The robot brake detection method according to claim 1, characterized in that: In step S10, if abs(Q2-Q0)>ℇ, where ℇ is the allowable change in motor position and the abs() function represents the absolute value, then the brake is damaged and brake detection cannot be performed.

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