Industrial robot collision protection method

Abstract

The invention provides an industrial robot collision protection method, and belongs to the technical field of robot safety control. The problem that in the prior art, objects or human bodies are continuously squeezed is solved. The industrial robot collision protection method comprises the steps that torque collision threshold values of all joints of a robot are calibrated in advance; acquiring position data, speed data and moment data of each joint of the robot; the real-time external torque of each joint is obtained based on a momentum observer model, the position data of each joint, the speed data and the torque data, the real-time external torque is compared with the torque collision threshold value of the corresponding joint, and when collision occurs, control is performed based on a corresponding collision strategy obtained based on the collision type. The collision strategy comprises an emergency stop control strategy for controlling each joint shaft motor to perform emergency stop operation and then generating reverse motion during collision and a flexible motion strategy for controlling the corresponding joint shaft motor to change from position control to torque control during collision. According to the invention, the damage to collision objects and personnel is effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of robot safety control and relates to a collision protection method for industrial robots. Background Art

[0002] Industrial robots, with their high precision, high stability, and strong environmental adaptability, have been widely used in various production and manufacturing fields. They can efficiently complete repetitive and single tasks and can replace manual operations in dangerous environments such as high temperature, toxic, and radiation. However, when robots cooperate with personnel or share the working space, there are potential mechanical collision risks, which may lead to equipment damage or personnel injury accidents.

[0003] At present, the contact collision detection methods for industrial robots and external objects are divided into two types: with sensors and without sensors. The collision detection scheme with sensors relies on six-axis force sensors, tactile skins, or lidar to directly measure the contact force or distance to determine whether a collision occurs; the collision detection scheme without sensors monitors internal parameters such as motor current / torque, joint angles, and end-effector forces in real time, determines the collision threshold based on the dynamic model and the expected motion trajectory, and triggers a collision judgment when the actual torque exceeds the threshold. After a collision occurs, the current processing strategy is usually to stop immediately. When the collision object is removed, the movement is resumed. However, this strategy will cause continuous extrusion of the object or the human body, resulting in damage or safety accidents. Summary of the Invention

[0004] The object of the present invention is to address the above problems existing in the prior art and propose a collision protection method for industrial robots. The technical problem to be solved is: how to reduce the damage to the collided objects and personnel.

[0005] The object of the present invention can be achieved by the following technical solutions: A collision protection method for industrial robots, including the following steps:

[0006] S1. Calibrate the torque collision thresholds of each joint of the robot in advance;

[0007] S2. The robot control system monitors the movement process of the robot and obtains the position data, speed data, and torque data of each joint of the robot;

[0008] S3. Based on the momentum observer model, the position data, speed data, and torque data of each joint, obtain the real-time external torque of each joint. Compare the real-time external torque with the torque collision threshold of the corresponding joint based on the collision judgment formula, and determine whether a collision occurs according to the comparison result;

[0009] S4. Control according to the corresponding collision strategy obtained based on the collision type during a collision. The collision strategy includes an emergency stop control strategy that controls each joint axis motor to perform an emergency stop operation and then generate reverse movement during a collision, and a flexible movement strategy that controls the corresponding joint axis motor to change from position control to torque control during a collision. The collision type includes flexible collision and rigid collision. When a flexible collision occurs, the emergency stop control strategy is used for control. When a rigid collision occurs, the flexible movement strategy is used for control.

[0010] When this industrial robot collision protection method is in use, the torque collision thresholds of each joint are pre-calibrated in advance; when the robot performs a certain task, the robot control system monitors the movement process of the robot in real time, and based on the motor data of the servo system, obtains the position data, speed data, and torque data of each joint of the robot; obtains the real-time external torque of each joint based on the momentum observer model, compares the obtained real-time external torque with the torque collision threshold to determine whether a collision occurs at which joint of the robot. This method does not use an external torque sensor, calculates the external torque through a momentum observer, first performs threshold measurement, and then performs collision detection, and can determine which joint axis has a collision, effectively improving the sensitivity of collision detection. During a collision, according to different collision types, select the corresponding collision strategy. If it collides with a flexible object, it is a flexible collision, and the emergency stop control strategy is used. If it collides with a rigid object, that is, a rigid collision, the flexible movement strategy is used, and the robot actively softens to adapt to the colliding object. Selecting the corresponding collision strategy according to different collision types can more effectively protect the safety of the colliding object or personnel and minimize the damage.

[0011] In the above industrial robot collision protection method, in the step S1, the operation of pre-calibrating the torque collision thresholds of each joint of the robot includes:

[0012] Control the robot to enter the threshold measurement mode;

[0013] Specify a working path, control the robot to run according to the specified working path, and continuously record the position data, speed data, and torque data of each joint of the robot;

[0014] Input the position data, speed data, and torque data of each joint into the momentum observer model, calculate the external torque of each joint at each moment, obtain the maximum external torque of each joint by comparing the external torques of the same joint at each moment, and calibrate it as the torque collision threshold of the corresponding joint, denoted as , where i represents a certain joint of the robot. The working path refers to the path for the robot to complete an action, such as a part transfer path, a welding path, a spraying path, etc. The robot body consists of movable rotating or translational connecting components, that is, joints, and each joint is driven by a servo motor. Performing threshold measurement along the working path can improve the accuracy of collision judgment.

[0015] In the above industrial robot collision protection method, in the step S1, the operation of pre-calibrating the torque collision threshold of each joint of the robot further includes:

[0016] Segment the specified working path, and then control the robot to run each segment of the working path, continuously record the position data, speed data and torque data of each joint of the robot for each segment of the working path;

[0017] Input the joint position data, speed data and torque data into the momentum observer model, calculate the external torque of each joint at each moment of each segment of the working path, and obtain the maximum external torque of each joint of each segment of the working path by comparing the external torques of the same joint at each moment of the same working path. Calibrate it as the torque collision threshold of a certain joint under a certain segment of the working path, denoted as , where i represents a certain joint of the robot and j represents a certain segment of the working path. Dividing a working path into multiple segments of working paths can improve the detection sensitivity and avoid the problems of too long working path and inaccurate judgment.

[0018] In the above industrial robot collision protection method, in the step S1, it further includes the operation of updating the torque collision threshold of each joint, and this operation includes:

[0019] Set the torque collision threshold update period. The robot runs normally according to the specified working path, and continuously records the joint position data, speed data and torque data of each joint of the robot within each period; input the joint position data, speed data and torque data into the momentum observer model to obtain the maximum external torque of each joint. When the maximum external torque of the joint in the current period is greater than the absolute value of the maximum external torque saved in the previous period, update the current maximum external torque as the torque collision threshold, otherwise, the torque collision threshold remains unchanged. By correcting the torque collision threshold in this way, the collision judgment sensitivity can be higher and more accurate, and the safety can be further improved.

[0020] In the above industrial robot collision protection method, in the step S3, the operation of obtaining the real-time external torque of each joint includes:

[0021] Establish a momentum observer model, and the formula is:

[0022]

[0023] Where: is the real-time external torque of the joint, is the diagonal gain matrix of the observer, p(t) is the generalized momentum of the robot at time t, p(0) is the generalized momentum of the robot at the initial time, , speed, is the joint torque, and define the matrix , represents the gravity matrix, represents the transpose of the centripetal force and Coriolis force matrices, is the observed value of;

[0024] Input the joint position data, velocity data, and torque data into the formula of the momentum observer model to obtain the real-time external torque of the joints. The application of the momentum observer model can process data such as the motor angle, velocity, and current in real time, quickly calculate and provide real-time feedback of the external torque information, enabling the robot to promptly sense changes in external forces, quickly adjust its actions or take protective measures, which helps improve the safety of the robot and personnel.

[0025] In the above industrial robot collision protection method, in the step S3, the operation of comparing the real-time external torque with the torque collision threshold corresponding to the joint based on the collision judgment formula includes:

[0026] Let the real-time external torque of each joint be , i = 1~n, j = 1~m, where n and m are positive integers;

[0027] The collision judgment formula is to compare the real-time external torque with the torque collision threshold where d s ≥ 1, is the sensitivity coefficient. When is greater than , it is determined that a collision has occurred; when is less than or equal to , it means that no collision has occurred. According to the subscript i, it can be determined which joint's external torque exceeds the limit and triggers a collision, and according to the subscript j, it can be determined which section of the path's external torque exceeds the limit and triggers a collision, thereby accurately knowing which joint has a collision in which section of the path, and thus making corresponding collision strategy feedback to ensure the safety of the robot and personnel.

[0028] In the above industrial robot collision protection method, in the step S4, the emergency stop control strategy is divided into control strategy one for reverse movement to the starting point and control strategy two for reverse movement to a specified position according to the reverse movement distance. Further dividing the emergency stop control strategy into control strategy one and control strategy two can better adapt to different working paths of the robot, and can play a more effective protective role and improve safety when a collision occurs.

[0029] In the above industrial robot collision protection method, in the step S4, control strategy one includes:

[0030] When it is determined that a collision has occurred, control the motors of each joint axis to perform an emergency stop operation;

[0031] Set the stop time when the robot comes to a complete stop;

[0032] When the stop time is reached, generate a reverse motion control command to control each joint of the robot to return to the starting point of the motion. The stop time can be set to 0.1s or other values can be set according to the situation. When the robot control system controls the motor to stop working, the motor does not stop immediately. At this time, each joint of the robot will still move forward a small distance before coming to a complete stop. Therefore, setting the stop time can ensure that reverse motion control is performed when the motor is completely stopped, and control each joint of the robot to return to the starting point of the motion according to the original working path, avoiding collision during the retraction and improving safety.

[0033] In the above industrial robot collision protection method, in the step S4, the control strategy two includes:

[0034] When it is judged that a collision occurs, control each joint axis motor to perform an emergency stop operation;

[0035] Set the stop time when the robot comes to a complete stop, a preset retraction distance value and speed;

[0036] When the stop time is reached, generate a reverse motion control command to control each joint of the robot to act at a preset speed and move backward a preset retraction distance value along the straight line path formed by the collision point and the stop point. The retraction distance value generally ranges from 30 to 100mm, and the speed is 30% - 80% of the reference speed. For example, if the reference speed is 300mm / s, then 30% is 90mm / s; moving backward a preset retraction distance value along the straight line path formed by the collision point and the stop point can release the extrusion force between the robot and the object, avoid damage to the flexible object due to continuous extrusion, ensure the safety of the flexible object, and preset a retraction distance value can effectively solve the collision problem and avoid hitting other objects, ensuring the safety of the robot or personnel.

[0037] In the above industrial robot collision protection method, in the step S4, the operations of the flexible motion strategy include:

[0038] When a collision occurs, control the control mode of any one or combination of the robot collision joint axis motor and the relevant joint axis motor to change from position control to torque control; the remaining joint axis motors still act in the position control mode and perform an emergency stop operation;

[0039] The preset mode recovery time controls the control mode of the robot joint axis motor to recover from torque control to position control when the mode recovery time is reached. The mode recovery time can be set from 1 s to 2 s. When setting, the mode recovery time is greater than the stop time. In this collision strategy, by controlling the mode switching of the corresponding joint axis motor, when the robot collides with a rigid object, the robot can actively soften and deform through mode switching to adapt to the rigid object, protecting both the robot and the rigid object from damage and improving the safety of robot operation. Delaying the mode recovery time and then switching the control mode back to position control and closing the loop at the current position ensures the subsequent stability of the robot.

[0040] Compared with the prior art, the industrial robot collision protection method of the present invention has the following advantages:

[0041] 1. The present invention can adopt corresponding collision strategies according to different collision objects, quickly release the extrusion force, reduce the damage caused by collision extrusion, and effectively protect the safety of equipment or personnel.

[0042] 2. The present invention first makes the robot run along the working path normally once, records the torque of each joint and extracts the torque collision threshold. For a longer path, it can also be processed in segments to obtain the most suitable torque collision threshold for each segment. When the robot moves along the same path later, once a collision occurs, it can achieve highly sensitive detection relying on these accurate torque collision thresholds, effectively improving the accuracy of collision detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is the control flowchart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0044] To make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0045] As Figure 1 shown, when the industrial robot collision protection method of the present invention is applied in an industrial robot, first, the torque collision thresholds of each joint of the robot are pre-calibrated. The operations include: controlling the robot to enter the threshold measurement mode; specifying a working path, such as a part transfer path; after the path is selected, controlling the robot to run along the specified working path normally once, and continuously recording the position data, speed data and torque data of each joint of the robot; inputting the position data, speed data and torque data of each joint into the momentum observer model. The formula of the momentum observer model is:

[0046]

[0047] Wherein: is the real-time external torque of the joint, is the diagonal gain matrix of the observer, p(t) is the generalized momentum of the robot at time t, and p(0) is the generalized momentum of the robot at the initial time, and velocity, is the joint torque, and the matrix is defined as represents the gravity matrix, represents the transpose of the centripetal force and Coriolis force matrix, is the observed value. Calculate the external torque of each joint at each moment according to the formula. By comparing the external torques of the same joint at each moment, obtain the maximum external torque of each joint, and calibrate it as the torque collision threshold of the corresponding joint, denoted as , where i represents a certain joint of the robot.

[0048] When a specified working path is relatively long, the working path is segmented. For example, if the specified working path is for the robot to transfer parts, the speed of one section of the path is relatively fast, reaching 80% of the speed, and then the robot needs to slowly lower the parts with a relatively slow speed of 10%. In this case, the working path is segmented according to the magnitude of the robot's movement speed and can be divided into two sections, and two thresholds are recorded respectively; the specific operation is as follows: after completing the segmentation of the working path, then control the robot to run each section of the working path, and continuously record the joint position data, speed data, and torque data of each section of the working path of the robot; input the joint position data, speed data, and torque data into the momentum observer model, calculate the external torque of each joint at each moment of each section of the working path according to the momentum observer model formula, obtain the maximum external torque of each joint of each section of the working path by comparing the external torques of the same joint at each moment of the same working path, and calibrate it as the torque collision threshold of a certain joint under a certain section of the working path, denoted as , where i represents a certain joint of the robot and j represents a certain section of the working path.

[0049] In order to improve the sensitivity of collision detection, set the update period of the torque collision threshold. The update period can be set to 2 ms or other specified time values. The robot runs normally according to the specified working path, and continuously records the joint position data, speed data, and torque data of each joint of the robot within each period; input the joint position data, speed data, and torque data into the momentum observer model, obtain the maximum external torque of each joint of each section of the working path. When the maximum external torque of the joint in the current period is greater than the absolute value of the maximum external torque saved in the previous period, update the current maximum external torque as the torque collision threshold, otherwise, the torque collision threshold remains unchanged.

[0050] After calibrating the torque collision thresholds of each joint, the robot control system monitors the robot's movement process and obtains the joint position data, speed data, and torque data of the robot. For data acquisition in this step, an external torque sensor may not be used, and only the servo system motor data is required. Specifically, the joint position data can be obtained according to the absolute encoder of the motor; the joint speed data is obtained by differentiating the joint position data; and the joint torque data is obtained by calculating the motor current.

[0051] Enter the real-time external torque calculation step for each joint: Input the joint position data, speed data, and torque data obtained in each segment of the working path into the momentum observer model. According to the formula Obtain the real-time external torque of each joint in each segment of the working path. Based on the collision judgment formula, compare the real-time external torque with the torque collision threshold of the corresponding working path and the corresponding joint. The comparison operations include:

[0052] Let the real-time external torque of each joint be , where i = 1~n, j = 1~m, and n and m are positive integers; the collision judgment formula is to compare the real-time external torque with the torque collision threshold . Among them, d s ≥1 is the sensitivity coefficient. When is greater than , it is judged that a collision has occurred; when is less than or equal to , it means that no collision has occurred. Among them, according to the subscript i, it can be determined which joint's external torque exceeds the limit and triggers a collision. According to the subscript j, it can be determined which segment of the path's external torque exceeds the limit and triggers a collision, thereby accurately knowing which joint has a collision in which segment of the path.

[0053] When a collision occurs, enter the collision protection step. Specifically, based on the collision type, obtain the corresponding collision strategy. The collision strategies include an emergency stop control strategy that controls the motors of each joint axis to perform an emergency stop operation and then generate a reverse movement when a collision occurs, and a flexible movement strategy that controls the corresponding joint axis motor to change from position control to torque control when a collision occurs. Among them, the emergency stop control strategy is divided into control strategy one for reverse movement to the starting point and control strategy two for reverse movement to a specified position according to the reverse movement distance.

[0054] The choice of collision strategy is based on the usage scenario of the robot. For example, if the robot is used for massaging people, it means the robot collides with a flexible object, that is, the collision type is flexible collision, and the emergency stop collision strategy is adopted. When choosing between control strategy one and control strategy two, it can be further selected according to the working path to ensure more effective protection of personnel or the robot. When choosing control strategy one for collision protection, control the motors of each joint axis to perform an emergency stop operation, stop the motors of each joint axis from moving, and set the stop time when the robot completely stops, such as 0.1 s; when the stop time is reached, generate a reverse motion control instruction to control each joint of the robot to return to the starting point of motion according to the original working path.

[0055] When choosing control strategy two for collision protection, control the motors of each joint axis to perform an emergency stop operation, stop the motors of each joint axis from moving, set the stop time when the robot completely stops, preset the retraction distance value and speed. The retraction distance value is generally taken as 30 - 100 mm, and the speed is 30% - 80% of the reference speed. For example, if the reference speed is 300 mm / s, then 30% is 90 mm / s; when the stop time is reached, generate a reverse motion control instruction to control each joint of the robot to move at the preset speed and reverse-move the preset retraction distance value along the straight-line path formed by the collision point and the stop point, thereby releasing the extrusion force between the robot and the object and avoiding damage to the flexible object due to continuous extrusion and ensuring the safety of the flexible object.

[0056] For another example, when a robot loads and unloads a machine tool, and the machine tool is a rigid object, the collision type is a rigid collision. The machine tool will not deform. Only the robot actively softens and deforms to adapt to the rigid machine tool, so that neither side will be damaged. For this rigid collision type, the flexible motion strategy in this method is adopted to control the control mode of any one or a combination of the collision joint axis motor and the relevant joint axis motor of the robot to change from position control to torque control; the remaining joint axis motors still operate in the position control mode and perform an emergency stop operation. For example, for a six-axis industrial robot, when a collision occurs, the 6th axis is the end joint axis motor, and the control motor immediately switches the control mode from position control to torque control, and the torque set value is 0. The other 1-5 axis motors are still in the position control mode and perform an emergency stop motion. When the 1-5 axis motors perform an emergency stop, they move forward a small distance, such as 1-2 mm. At this time, the 6th axis is already in the torque mode and will become very soft, able to passively adapt to the extrusion state and passively adjust its own angle to relieve the extrusion between the tooling at the end of the 6th axis and the collided object, achieving the effect of protecting the robot and the collided object. In the control of this strategy, the axis for switching the control mode is not limited to the 6th axis and can be any one or a combination of the 1st, 4th, 5th, and 6th axes. The 2nd and 3rd axes do not perform mode switching. After completing the mode switching and emergency stop actions, a preset mode recovery time is set. When the mode recovery time is reached, the control mode of the robot joint axis motor is restored from torque control to position control, and it is closed-loop at the current position to ensure the subsequent stability of the robot.

[0057] This method sets three collision strategies, which can adapt to different collision objects, quickly release the extrusion force when a collision occurs, reduce the damage caused by the collision extrusion, and effectively protect the safety of equipment or personnel.

[0058] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art of the present invention can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. An industrial robot collision protection method, characterized in that, The industrial robot collision protection method includes the following steps: S1. Calibrate the torque collision thresholds of each joint of the robot in advance; S2. The robot control system monitors the movement process of the robot to obtain the position data, speed data and torque data of each joint of the robot; S3. Based on the momentum observer model, the position data, speed data and torque data of each joint, obtain the real-time external torque of each joint. Compare the real-time external torque with the torque collision threshold of the corresponding joint based on the collision judgment formula, and judge whether a collision occurs according to the comparison result; S4. When a collision occurs, control is performed based on the corresponding collision strategy obtained according to the collision type. The collision strategy includes an emergency stop control strategy for controlling the motors of each joint axis to perform an emergency stop operation and then generating a reverse movement, and a flexible movement strategy for controlling the corresponding joint axis motor to change from position control to torque control when a collision occurs. The collision type includes flexible collision and rigid collision. When a flexible collision occurs, the emergency stop control strategy is used for control. When a rigid collision occurs, the flexible movement strategy is used for control.

2. The industrial robot collision protection method according to claim 1, wherein In the step S1, the operation of calibrating the torque collision thresholds of each joint of the robot in advance includes: Control the robot to enter the threshold measurement mode; Specify a working path, control the robot to run according to the specified working path, and continuously record the position data, speed data and torque data of each joint of the robot; Input the joint position data, velocity data, and torque data into the momentum observer model to calculate the external torque of each joint at each moment. By comparing the external torques of the same joint at each moment, obtain the maximum external torque of each joint, and calibrate it as the torque collision threshold of the corresponding joint, denoted as , where i represents a certain joint of the robot.

3. The industrial robot collision protection method according to claim 2, wherein In the step S1, the operation of calibrating the torque collision thresholds of each joint of the robot in advance further includes: Segment the specified working path, and then control the robot to run each segment of the working path, and continuously record the position data, speed data and torque data of each joint of each segment of the working path of the robot; Input the joint position data, velocity data, and torque data into the momentum observer model to calculate the external torque of each joint at each moment of each working path. By comparing the external torques of the same joint at each moment of the same working path, obtain the maximum external torque of each joint of each working path, and calibrate it as the torque collision threshold of a certain joint under a certain working path, denoted as , where i represents a certain joint of the robot and j represents a certain working path.

4. The industrial robot collision protection method according to claim 2 or 3, characterized in that, In the step S1, it further includes the operation of updating the torque collision threshold of each joint, and this operation includes: Set the torque collision threshold update period; The robot runs normally according to the specified working path, and continuously records the position data, speed data and torque data of each joint of the robot within each period; input the position data, speed data and torque data of each joint into the momentum observer model to obtain the maximum external torque of each joint. When the maximum external torque of the joint in the current period is greater than the absolute value of the maximum external torque saved in the previous period, update the current maximum external torque to the torque collision threshold. Otherwise, the torque collision threshold remains unchanged.

5. The industrial robot collision protection method according to claim 1 or 2 or 3, characterized in that, In the step S3, the operation of obtaining the real-time external torque of each joint includes: Establish a momentum observer model, and the formula is: ； Wherein: is the real-time external torque of the joint, is the diagonal gain matrix of the observer, p(t) is the generalized momentum of the robot at time t, and p(0) is the generalized momentum of the robot at the initial time, and velocity, is the joint torque, and the matrix is defined as represents the gravity matrix, represents the transpose of the centripetal force and Coriolis force matrix, is the observed value of; Input the joint position data, speed data and torque data into the formula of the momentum observer model, so as to obtain the real-time external torque of the joint.

6. The industrial robot collision protection method according to claim 3, characterized in that In the step S3, the operation of comparing the real-time external torque with the torque collision threshold of the corresponding joint based on the collision judgment formula includes: Let the real-time external torque of each joint be , where \(i = 1\sim n\), \(j = 1\sim m\), and \(n\) and \(m\) are positive integers; The collision judgment formula is to compare the real-time external torque with the torque collision threshold . When is greater than , it is judged that a collision has occurred. Among them, d s ≥1 is the sensitivity coefficient; when is less than or equal to , it means that no collision has occurred.

7. The industrial robot collision protection method according to claim 1, characterized in that, In the step S4, the emergency stop control strategy is divided into control strategy one for reverse movement to the starting point and control strategy two for reverse movement to a specified position according to the distance of the reverse movement.

8. The industrial robot collision protection method according to claim 7, characterized in that, In the step S4, the control strategy one includes: When it is judged that a collision occurs, control the motors of each joint axis to perform an emergency stop operation; Set the stop time when the robot completely stops; When the stop time is reached, a reverse motion control instruction is generated to control each joint of the robot to return to the starting point of the motion.

9. The industrial robot collision protection method according to claim 7 or 8, characterized in that, In the step S4, the control strategy 2 includes: When a collision is determined to occur, the motors of each joint axis are controlled to perform an emergency stop operation; Set the stop time when the robot completely stops, and preset the retraction distance value and speed; When the pre-stop time is reached, a reverse motion control instruction is generated to control each joint of the robot to act at a preset speed, and reverse-move along the straight-line path formed by the collision point and the stop point to the preset retraction distance value.

10. The industrial robot collision protection method according to claim 1, characterized in that, In the step S4, the operations of the flexible motion strategy include: When a collision occurs, control the control mode of any one or a combination of the collision joint axis motor and the relevant joint axis motors of the robot to change from position control to torque control; the remaining joint axis motors still act in the position control mode and perform an emergency stop operation; Preset the mode recovery time, and when the mode recovery time is reached, control the control mode of the robot joint axis motor to recover from torque control to position control.

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