A control method of an electric gripper

Abstract

The application discloses a control method of an electric clamp jaw and relates to the technical field of electric clamp jaws. The control method adopts a rebound suppression algorithm. In a normal state, a collision detection signal is detected. When a current value of the clamp jaw detected in the state is greater than a collision detection current threshold value, a reverse pulling state is entered. In the state, a reverse driving current is used to drive the clamp jaw to move at a positive deceleration and a reverse acceleration. When the clamp jaw reaches a deepest position, a positive pushing state is entered. In the state, a positive driving current is used to drive the electric clamp jaw. When a speed of the clamp jaw is less than a first preset value, the normal state is switched, and a workpiece clamping operation is completed. Through the rebound suppression algorithm, the kinetic energy of the clamp jaw is consumed after the collision is detected, the clamping suppression purpose is achieved, no additional components are introduced, and the clamp jaw does not depend on the size of the clamped workpiece. The problems introduced by the additional mechanical buffer unit and the pre-clamping mode are solved.

Description

Technical Field

[0001] This invention relates to the field of electric gripper technology, specifically a control method for an electric gripper. Background Technology

[0002] With the continuous advancement of industrialization, electric grippers have been widely used in automated production due to their advantages such as precise control, high adaptability, low cost and high efficiency. This has led to increasingly higher requirements for the operating cycle and force control accuracy of grippers in various application scenarios. When grippers quickly clamp onto rigid objects, they generate a large reaction force, which may cause severe rebound or even multiple rebounds and oscillations. It takes a long time for such rebounds to recover to a stable state, which greatly slows down the operating cycle of the grippers and also causes torque oscillations when gripping objects.

[0003] Current technologies often employ methods such as adding a mechanical buffer unit (e.g., compression spring, elastic washer, or hydraulic damper) between the gripper drive mechanism and the gripper fingers, or using a pre-gripping method (decelerating the gripper while it is still some distance from the object to be gripped, thus gripping it slowly) to mitigate the problem. However, while these methods effectively alleviate gripping rebound, they also introduce new problems:

[0004] 1. Add a mechanical buffer unit: When an impact force is generated during clamping, the mechanical buffer unit absorbs kinetic energy through deformation and reduces the rebound amplitude. However, the spring deformation recovery time is much longer than the motor response time, which increases the clamping cycle. The buffer space occupies the transmission stroke, which leads to an increase in the end repetitive positioning error. In addition, the spring stress concentration under high-frequency compression leads to plastic deformation or fracture, introducing a short service life.

[0005] 2. Pre-clamping method: When the size of the clamped object is fixed, the pre-clamping method limits the speed before the collision to ensure that the clamping does not cause a rebound, thus increasing the clamping time. When the size of the clamped object is not fixed, the pre-clamping method will fail and rebound will occur again. It is necessary to recalibrate the speed and switch the position point. The low-speed running stroke will increase as the clamped object changes from large to small, which will further extend the clamping time.

[0006] Based on this, a control method for an electric gripper is provided, which can eliminate the drawbacks of existing technical solutions. Summary of the Invention

[0007] The purpose of this invention is to provide a control method for an electric gripper to solve the problems introduced by adding a mechanical buffer unit and a pre-gripping method in the prior art.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A control method for an electric gripper employs a rebound suppression algorithm. The control system controls the electric gripper to perform workpiece clamping. The state machine of the control system includes a normal state, a collision detection state, a reverse pull state, and a forward push state. The rebound suppression algorithm specifically includes:

[0010] Under normal conditions, the electric gripper closes rapidly in the forward direction to perform workpiece clamping, calculates parameters for collision detection, and determines whether the parameters meet the third preset value and the maximum speed threshold. If they do, the collision detection state is entered after the collision detection current threshold is detected.

[0011] When the collision detection state is activated, the electric gripper enters the reverse pull state when the current value of the electric gripper is detected to be greater than the collision detection current threshold.

[0012] In the reverse pull state, the electric gripper is driven by the reverse drive current to perform forward deceleration and reverse acceleration. When the electric gripper is detected to have reached the deepest position, it enters the forward push state.

[0013] In the forward push state, the electric gripper is driven by a forward drive current. When the speed of the electric gripper is detected to be less than a first preset value, the system switches to the normal state to complete the workpiece clamping operation.

[0014] Preferably, the forward pushing state includes:

[0015] During the constant thrust phase, the driving current is related to the target current and the target velocity, and the constructed function is: ,in, For the target current, For the target speed, For the driving current during the constant force push phase, These are constant coefficients;

[0016] The force reduction push phase: The driving current in the force reduction push phase decreases as the speed of the electric gripper decreases, and the construction function is: ,in, For the driving current during the deceleration and pushing phase, Given the target current, the virtual damping force is proportional to the velocity, satisfying... , These are constant coefficients.

[0017] Preferably, during the constant force pushing phase, when the current speed of the electric gripper is detected to be less than a second preset value, the force reduction pushing phase is initiated.

[0018] Preferably, a compensation current is added during the force reduction push phase to reduce the duration of the force reduction push phase.

[0019] Preferably, the control system uses sudden changes in command current as a collision detection signal, eliminates torque fluctuations caused by reducer installation errors and friction through torque feedforward, and uses the sum of the maximum current value of the electric gripper when it reaches the set maximum speed and runs smoothly with the torque feedforward parameter as the collision detection current threshold to detect the collision detection signal. When the change in command current exceeds the set current difference threshold, and the change occurs in the collision detection state, it is determined that the electric gripper is colliding with the workpiece and enters the reverse pull state.

[0020] Preferably, in the collision detection state, when the current speed of the electric gripper is detected to be less than a third preset value, the system switches to the normal state and uses the target current to drive the workpiece clamping.

[0021] Preferably, the electric gripper is controlled by a control system to perform workpiece clamping. The state machine of the control system includes a normal state, an acceleration state, a transient state, a collision detection state, a reverse pull state, a forward push state, and a return to normal mode state.

[0022] The control method includes:

[0023] Step 1: Start the electric gripper clamping operation. At this time, the state machine is in the normal state.

[0024] Step 2: Determine whether the rebound suppression algorithm of the electric gripper is enabled. If enabled, continue to step 3. If not enabled, directly complete step 9 in the normal state.

[0025] Step 3: When the state machine is in normal state, determine whether the difference between the reference speed and the feedback speed is greater than the third preset value. If it is satisfied, it means that the driving component is accelerating and enters the acceleration state.

[0026] Step 4: When the state machine is in the acceleration state, detect whether the feedback speed has reached the maximum speed threshold. If it does, enter the transient state.

[0027] Step 5: When the state machine is in a transient state, it enters the collision detection state after detecting the collision detection current threshold.

[0028] Step 6: When the state machine is in the collision detection state, if the current reference current value is detected to be greater than the collision detection current threshold, it indicates that a collision has occurred and enters the reverse pull state. If the current speed is detected to drop to the third preset value, it indicates that the electric gripper has operated normally and no collision has occurred. It directly enters the return to normal mode state and continues to execute step 9.

[0029] Step 7: When the state machine is in the reverse pull state, the electric gripper is driven to perform forward deceleration and reverse acceleration with the maximum reverse drive current. If it is detected that the distance between the current position and the initial position of the electric gripper is less than the distance between the position and the initial position of the previous cycle, it means that the electric gripper has reached the deepest collision position and has started to rebound. Calculate the maximum thrust at this time and switch the state machine to the forward push state.

[0030] Step 8: When the state machine is in the forward push state, if the feedback speed is detected to be less than the first preset value, it will enter the return to normal mode state.

[0031] Step 9: When the state machine is in the return to normal mode state, the switching torque is limited to the target torque set by the control system, and the state is switched to the normal state.

[0032] Step 10: The grippers complete the clamping operation.

[0033] Preferably, step 8 specifically includes:

[0034] Step 81: When the state machine is in the forward push state, the electric gripper is driven in the forward direction by a constant high current. If the current reference speed is detected to drop to the second preset value, the state is switched to the reduced push state.

[0035] Step 82: When the state machine is in the force reduction push state, the electric gripper is driven in the positive direction by a linearly decreasing force reduction current. When the feedback speed of the electric gripper is detected to be less than the first preset value, the machine returns to the normal mode state.

[0036] Preferably, the reference speed is the speed command value set by the control system that the electric gripper is expected to reach, the feedback speed is the speed information that the electric gripper feeds back to the control system in real time during actual operation, and the reference current value is the current reference value set by the control system.

[0037] Preferably, the maximum speed threshold is the maximum operating speed set during the operation of the electric gripper, the third preset value is 0.25 times the maximum speed threshold, the second preset value is 0.35 times the maximum rebound speed, and the maximum rebound speed is the maximum speed that the electric gripper can reach during the rebound process after reaching the deepest collision position.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] 1. This invention provides a control method for an electric gripper. By using a rebound suppression algorithm, after a collision is detected, the kinetic energy of the gripper is consumed in the drive coil instead of the object being gripped, thereby suppressing the rebound. It only requires adding a piece of code for the rebound suppression algorithm to the original magnetic field orientation control process. No additional components are introduced, and it does not depend on the size of the object being gripped, thus effectively solving the problems introduced by adding a mechanical buffer unit and pre-gripping method.

[0040] 2. In selecting the collision detection signal, this invention uses a command current mutation signal to improve the speed and sensitivity of detection, reduce the detection threshold, achieve rapid detection, and avoid false triggering. It adopts a fast-then-slow approach and establishes the functional relationship between the target velocity, target current, and pusher current under the constant force push stage and the reduced force push stage, respectively, to ensure that the gripper can quickly stabilize at the target position without secondary collision. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the bounce suppression algorithm of the present invention.

[0042] Figure 2 This is a schematic diagram of the steps of the control method of the present invention.

[0043] Figure 3 This is a schematic diagram of the reference torque, velocity feedback, and position feedback curves for each stage of the present invention.

[0044] Figure 4 This is a comparison chart showing the actual application effects of the rebound suppression algorithm of this invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0046] like Figure 1 - Figure 3 As shown, a control method for an electric gripper involves a control system that controls the electric gripper to clamp the workpiece. A rebound suppression algorithm for the electric gripper is employed. During the rebound suppression process, the state machine of the control system includes a normal state, a collision detection state, a reverse pull state, and a forward push state. The rebound suppression algorithm specifically includes:

[0047] Under normal conditions, the electric gripper closes rapidly in the forward direction to perform workpiece clamping. It calculates parameters for collision detection and determines whether the parameters meet the third preset value and the maximum speed threshold. If they meet the requirements, it enters the collision detection state after detecting the collision detection current threshold. In the collision detection state, when the current reference current value of the electric gripper is detected to be less than the first preset value, it switches to the normal state and completes workpiece clamping by driving the target current.

[0048] When the collision detection state is activated, the electric gripper enters the reverse pull state when the current reference current value is detected to be greater than the collision detection current threshold.

[0049] In the reverse pull state, the electric gripper is driven by the reverse drive current to perform forward deceleration and reverse acceleration. When the electric gripper is detected to have reached the deepest position, it enters the forward push state. At this time, the maximum reverse current of the drive component is 1.2 to 1.5 times the rated current of the drive component. This operation can minimize the compression depth, thereby reducing the rebound force.

[0050] In the forward pushing state, the electric gripper is driven by the forward driving current. When the speed of the electric gripper is detected to be less than the first preset value, it switches to the normal state and completes the workpiece clamping operation. This operation can ensure that the electric gripper is fast and stable without generating secondary rebound.

[0051] Specifically, such as Figure 3 As shown, the curves depicting the reference current, feedback speed, and feedback position during four stages—collision detection, reverse pull, forward push, and normal workpiece clamping operation—are illustrated. The blue curve represents the given reference current, the yellow curve represents the feedback position, and the red curve represents the feedback speed. Stage a represents the constant force push stage, stage b represents the reduced force push stage, and the forward push state includes:

[0052] During the constant thrust phase, the driving current is related to the target current and the target velocity. The smaller the target current or the smaller the target velocity, the smaller the thrust. Therefore, we can assume that the three factors change linearly, and construct the function as follows: ,in, For the target current, For the target speed, For the driving current during the constant force push phase, As a constant coefficient, the target current is selected by setting a specific value. and target speed The required thrust to prevent the clamped object from rebounding was verified, the coefficient was calculated, and the thrust under arbitrary target velocity and target current was determined based on the construction function. Corresponding to the current form, the thrust is controlled by the current. In the electric gripper scenario, the output force is often represented by the current. It is the control quantity acting on the electric gripper at this stage. Under the constant force thrust stage, when the current speed of the electric gripper is detected to be less than the second preset value, the force reduction thrust stage is entered.

[0053] The force reduction push phase: During the force reduction push phase, the drive current decreases as the speed of the electric gripper decreases until the electric gripper stabilizes at the desired position. The construction function is: ,in, For the driving current during the deceleration and pushing phase, When the target current is small, the settling time is long. Therefore, when the target current is small, a larger force is used to stabilize the system first, and then the system is switched to the target current. At this time, it can be assumed that the virtual damping force is proportional to the velocity, satisfying the following condition. , These are constant coefficients. To adjust the movement speed of the gripper, a compensating current is added during the force reduction and pushing phase. To reduce the duration of the deceleration thrust phase, the function is constructed as follows: And define a linear expression: ,in, This is the current compensation amount. , As constant coefficients, the coefficients are calculated by selecting specific target currents and drive currents at their maximum and minimum values. , .

[0054] Among them, such as Figure 2 As shown, the control system uses the sudden change in command current as the collision detection signal. It eliminates torque fluctuations caused by reducer installation errors and friction through torque feedforward. The maximum current value of the electric gripper when it reaches the set maximum speed and runs smoothly is used as the collision detection current threshold value and the torque feedforward parameter. The collision detection signal is detected. When the change in command current exceeds the set current difference threshold value and the change occurs in the collision detection state, it is determined that the electric gripper is colliding with the workpiece and enters the reverse pull state. The sudden change in command current is used as the collision signal.

[0055] Specifically, while avoiding false detections, this operation can detect collision detection signals as early as possible. The reason for using a sudden change in command current as the collision detection signal is as follows:

[0056] Compared to velocity mutation, the change in command current is more obvious and easier to detect. The change in command current is several times amplified by the change in velocity. In addition, the velocity change at the moment of collision is small and easily overwhelmed by velocity fluctuations, making it difficult to detect accurately and quickly.

[0057] Compared to feedback current mutations, command current mutations occur earlier, and changes in the command current will lead to changes in the feedback current. Command current mutation signals are cleaner, while feedback current contains noise and is prone to false triggering. Some products using hardware current loops cannot obtain feedback current values, while command current mutations are always present and are easy to detect.

[0058] A control method for an electric gripper is disclosed, wherein the electric gripper is controlled by a control system to perform workpiece clamping. The state machine of the control system includes a normal state, an acceleration state, a transient state, a collision detection state, a reverse pull state, a forward push state, and a return to normal mode state. The control system is the core control unit for the operation of the electric gripper, responsible for executing various control logics including a rebound suppression algorithm. The control system pre-sets a target speed (i.e., the speed command value that the electric gripper is expected to reach) as the speed reference for the gripper's operation. In the algorithm flow, the control system can calculate the maximum speed threshold and torque feedforward for collision detection. By comparing the reference speed with the actual feedback speed, it determines whether the drive component is in an acceleration state and switches the operating state of the state machine accordingly, thereby achieving precise control of the electric gripper's movement. The maximum speed threshold is the maximum operating speed set during the operation of the electric gripper, which serves as the benchmark for the high-speed operation of the electric gripper, ensuring that the speed is controllable during clamping. The torque feedforward can compensate in advance for torque fluctuations caused by interference factors such as reducer installation errors and friction, reducing the collision detection threshold and avoiding misjudgment of collisions due to interference signals.

[0059] like Figure 2 As shown, the specific control methods include:

[0060] Step 1: Start the electric gripper clamping operation. At this time, the state machine is in normal state.

[0061] Step 2: Determine whether the rebound suppression algorithm of the electric gripper is enabled. If enabled, continue to step 3. If not enabled, complete step 9 directly in normal mode. When rebound suppression is not required (such as when gripping a flexible object), you can directly enter the normal mode to avoid redundant algorithm operation and save system resources. When enabled, the suppression process is executed according to the preset logic to adapt to different scenario requirements.

[0062] Step 3: When the state machine is in normal state, determine whether the difference between the reference speed and the feedback speed is greater than the third preset value. If it is, it means that the drive component is accelerating and enters the acceleration state. The reference speed is the speed command value set by the control system and expected to be reached by the electric gripper. The feedback speed is the speed information fed back to the control system in real time during the actual operation of the electric gripper. During the actual operation of the gripper, the speed information fed back to the control system in real time through sensors (such as encoders) is used to compare with the reference speed to realize closed-loop control. The third preset value is 0.25 times the maximum speed threshold. The maximum speed threshold is the maximum operating speed set during the operation of the electric gripper.

[0063] Step 4: When the state machine is in the acceleration state, check whether the feedback speed has reached the maximum speed threshold. If it does, enter the transient state.

[0064] Step 5: When the state machine is in a transient state, after detecting the collision detection current threshold, it enters the collision detection state. The collision detection current threshold is the sum of the maximum current value of the electric gripper when it reaches its maximum speed and runs smoothly, and the torque feedforward parameter.

[0065] Step 6: When the state machine is in the collision detection state, if the current reference current value is detected to be greater than the collision detection current threshold, it indicates that a collision has occurred and enters the reverse pull state. If the current speed is detected to drop to the first preset value, it indicates that the electric gripper has run normally and no collision has occurred. It directly enters the return to normal mode state and continues to execute step 9. The reference current value is the current reference value set by the control system. During the entire operation of the electric gripper, the reference current value will be adjusted according to different control stages and objectives to provide power support for the action of the electric gripper. Its change directly reflects the change of the output force of the drive component.

[0066] Step 7: When the state machine is in the reverse pull state, the electric gripper is driven by the maximum reverse drive current to perform forward deceleration and reverse acceleration. If it is detected that the distance between the current position and the initial position of the electric gripper is less than the distance between the position and the initial position of the previous cycle, it means that the electric gripper has reached the deepest collision position and has started to rebound. Calculate the maximum thrust at this time and switch the state machine to the forward push state. The maximum thrust is the constant large thrust applied to the electric gripper during the constant force push phase.

[0067] Step 8: When the state machine is in the forward push state, if the detected feedback speed is less than the first preset value, it will enter the return to normal mode state. The first preset value is a value close to 0.

[0068] Step 9: When the state machine is in the return to normal mode state, switch the torque limit to the target torque set by the control system, switch the state to normal state, so that after the electric gripper completes the anti-rebound action, it can work normally with a stable torque that meets the working requirements, ensuring that the electric gripper has a suitable clamping force on the workpiece. It will not cause the workpiece to fall due to too small a torque, nor will it damage the workpiece or the electric gripper itself due to too large a torque, thus ensuring the stability and reliability of the electric gripper's operation.

[0069] Step 10: The grippers complete the gripping operation and wait for the next gripping command.

[0070] Specifically, step 8 includes:

[0071] Step 81: When the state machine is in the forward push state, the electric gripper is driven in the forward direction by a constant high current. If the current reference speed is detected to drop to the second preset value, the state is switched to the reduced push state. The second preset value is 0.35 times the maximum rebound speed. The maximum rebound speed is the maximum speed that the gripper can reach during the rebound process after reaching the deepest collision position. After the collision, it is used to generate a reverse force to quickly suppress the forward movement of the electric gripper.

[0072] Step 82: When the state machine is in the force reduction push state, the electric gripper is driven in the positive direction by a linearly decreasing force reduction current. When the feedback speed of the electric gripper is detected to be less than the first preset value, the machine enters the normal mode state.

[0073] Example 1

[0074] For details, please refer to [link / reference]. Figure 4 The clamping settling time was compared with and without the rebound suppression algorithm under three conditions: speed 255, torque 255, speed 255, torque 30, and speed 255, torque 0 (the numbers 255, etc., are per-unit values; 255 represents the maximum settable speed and maximum force, and 0 represents the minimum settable speed and minimum force). The top row shows the clamping effect without the rebound suppression algorithm, and the bottom row shows the clamping effect with the rebound suppression algorithm (cyan curve: given reference current; red curve: clamping speed feedback; yellow curve: clamping position feedback). It can be seen that the clamping cycle time is significantly shortened after using the rebound suppression algorithm, especially under fast and small force conditions.

[0075] The scenario is as follows: An electric gripper test platform with closed-loop speed and torque control is selected. A per-unit value system is set, with maximum speed and maximum torque corresponding to a per-unit value of 255, and minimum speed and minimum force corresponding to a per-unit value of 0. Three test conditions are configured:

[0076] Operating Condition 1: Speed ​​per unit value 255, Torque per unit value 255 (High speed, high force);

[0077] Operating Condition 2: Speed ​​per unit value 255, Torque per unit value 30 (high speed, low force);

[0078] Operating Condition 3: Speed ​​per unit value 255, Torque per unit value 0 (high speed, minimum force);

[0079] The electric gripper test platform under the above three working conditions was divided into two groups. The two groups were identical except for whether or not the rebound suppression algorithm was used. One group was set as the group without the suppression algorithm and the other group was set as the group with the suppression algorithm.

[0080] The specific experimental procedure is as follows:

[0081] Without using the suppression algorithm group: Directly enable the electric gripper's normal position or force control mode, send speed and torque commands according to the above three working conditions, collect and record data through sensors, and record data including given reference current (cyan curve), gripping speed feedback (red curve) and gripping position feedback (yellow curve), and count the time from the issuance of the command to the gripper stabilizing (position fluctuation < ±0.1mm, speed fluctuation < ±10rpm);

[0082] Using the suppression algorithm group: Embed the rebound suppression algorithm described in this method into the control system, repeat the above three working condition tests, and collect three curve data and count the stabilization time;

[0083] The settling time and curve fluctuation characteristics of the two sets of experiments under different operating conditions were analyzed, and the two sets of data were compared.

[0084] Condition 1 (High-speed and high-intensity): Compare the number of high-frequency oscillations in the position feedback curve when the algorithm is not used, and record the oscillation amplitude attenuation ratio and the amount of reduction in stabilization time after using the algorithm;

[0085] Operating Condition 2 (High Speed, Low Force): Focus on observing the rebound peak of the speed feedback curve (when the algorithm is not used, speed reverse overshoot may occur) and the change in stabilization time;

[0086] Working condition 3 (high speed and minimal force): Analyze the "drift-stabilization" process of the position feedback curve, compare the secondary position offset caused by the rebound when the algorithm is not used, the offset elimination after using the algorithm, and the stabilization time data;

[0087] Based on three sets of working condition data, it is concluded that regardless of the torque magnitude, the rebound suppression algorithm can shorten the clamping stabilization time and reduce the amplitude of speed and position fluctuations. Especially in high-speed, low-force scenarios, the impact force accounts for a higher proportion when the gripper contacts the object, and the algorithm's rebound suppression effect is more prominent. This provides data support for the algorithm's applicable scenarios, ensuring that the gripper can quickly stabilize at the target position without secondary collisions.

[0088] In summary, the control method of this electric gripper, through the rebound suppression algorithm, can dissipate the kinetic energy of the gripper in the drive coil instead of the object being gripped after a collision is detected, thereby achieving the purpose of suppressing rebound. It does not introduce additional components and is not dependent on the size of the object being gripped, thus effectively solving the problems introduced by adding mechanical buffer units and pre-gripping methods, and has good application prospects.

[0089] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A control method of an electric clamp jaw, employing a bounce suppression algorithm of an electric clamp jaw, characterized by, The control system controls the electric clamping jaw to perform workpiece clamping, a state machine of the control system includes a normal state, a collision detection state, a reverse pulling state and a forward pushing state, and the bounce suppression algorithm specifically includes: In the normal state, the electric clamping jaw is quickly closed in the positive direction to perform workpiece clamping, parameters for collision detection are calculated, it is judged whether the parameters meet the third preset value and the maximum speed threshold, if yes, after the collision detection current threshold is detected, the collision detection state is entered; In the collision detection state, when the current value of the electric clamping jaw is greater than the collision detection current threshold, the reverse pulling state is entered; In the reverse pulling state, the electric clamping jaw is driven by a reverse driving current to move in the positive direction at a deceleration and in the reverse direction at an acceleration, when it is detected that the electric clamping jaw reaches the deepest position, the forward pushing state is entered; In the forward pushing state, the electric clamping jaw is driven by a forward driving current, when it is detected that the speed of the electric clamping jaw is less than the first preset value, the normal state is switched to, and the workpiece clamping operation is completed; Wherein, the constant force stage, the drive current of the constant force stage and the target current, target speed exist relationship, the function is: Wherein, The target current is I, The target speed is V, The drive current of the constant force stage is I, The constant coefficient is K. deceleration stage: the driving current of the deceleration stage is reduced as the speed of the electric clamping jaw decreases, and the construction function is: wherein, is the driving current of the deceleration stage, is a target current, the virtual damping force is proportional to the speed, and satisfies , is a constant coefficient; Wherein, the control system takes the sudden change of the command current as the collision detection signal, the torque fluctuation caused by the installation error of the speed reducer and the friction force is eliminated through torque feedforward, the sum of the maximum current value when the electric clamping jaw runs smoothly after reaching the set maximum speed and the torque feedforward parameter is taken as the collision detection current threshold, the collision detection signal is detected, when the change amount of the command current exceeds the set current difference threshold, and the change occurs in the collision detection state, it is judged that the electric clamping jaw collides with the workpiece, and the reverse pulling state is entered.

2. The control method according to claim 1, characterized by, In the constant force pushing phase, when it is detected that the current speed of the electric clamping jaw is less than the second preset value, the force reduction pushing phase is entered.

3. The control method according to claim 1, characterized by, In the force reduction pushing phase, a compensation current is added to reduce the duration of the force reduction pushing phase.

4. The control method according to claim 1, characterized by, In the collision detection state, when it is detected that the current speed of the electric clamping jaw is less than the third preset value, the normal state is switched to, and the workpiece clamping is completed by driving the target current.

5. The control method according to claim 2, characterized by, The control system controls the electric clamping jaw to perform workpiece clamping, a state machine of the control system includes a normal state, an acceleration state, a transient state, a collision detection state, a reverse pulling state, a forward pushing state and a return to normal mode state; The control method includes: Step 1, starting the electric clamping jaw clamping operation, at this time the state machine is in the normal state; Step 2, judging whether to enable the bounce suppression algorithm of the electric clamping jaw, if yes, step 3 is continued, if not, step 9 is directly completed in the normal state; Step 3, when the state machine is in the normal state, judging whether the difference between the reference speed and the feedback speed is greater than the third preset value, if yes, it indicates that the driving member is accelerating, and the acceleration state is entered; Step 4, when the state machine is in the acceleration state, detecting whether the feedback speed reaches the maximum speed threshold, if yes, the transient state is entered; Step 5, when the state machine is in the transient state, after the collision detection current threshold is detected, the collision detection state is entered; Step 6, when the state machine is in the collision detection state, detecting whether the current speed of the electric clamping jaw is less than the third preset value, if yes, the normal state is switched to, and the workpiece clamping is completed by driving the target current; Step 7, when the state machine is in the reverse pulling state, detecting whether the current speed of the electric clamping jaw is less than the second preset value, if yes, the forward pushing state is entered; Step 8, when the state machine is in the forward pushing state, detecting whether the current speed of the electric clamping jaw is less than the first preset value, if yes, the normal state is switched to, and the workpiece clamping is completed by driving the target current; Step 9, when the state machine is in the return to normal mode state, the normal state is directly entered. Step 6, when the state machine is in the collision detection state, if the current reference current value is detected to be greater than the collision detection current threshold value, it indicates that a collision occurs, and the state machine enters the reverse pulling state; if the current speed is detected to drop to a third preset value, it indicates that the electric clamp jaw is normally operated to the position and no collision occurs, and the state machine directly enters the back to normal mode state and continues to perform step 9; Step 7, when the state machine is in the reverse pulling state, the electric clamp jaw is driven at a maximum reverse driving current to move forward at a deceleration and reverse at an acceleration; if the distance between the current position of the electric clamp jaw and the initial position is detected to be less than the distance between the previous period position and the initial position, it indicates that the electric clamp jaw has reached the deepest collision position and starts to rebound, the maximum thrust at this time is calculated, and the state machine is switched to the forward pushing state; Step 8, when the state machine is in the forward pushing state, if the feedback speed is detected to be less than a first preset value, the state machine enters the back to normal mode state; Step 9, when the state machine is in the back to normal mode state, the torque limit is switched to the target torque set by the control system, and the state is switched to the normal state; Step 10, the clamp jaw completes the clamping operation.

6. The control method according to claim 5, characterized by The step 8 specifically includes: Step 81, when the state machine is in the forward pushing state, the electric clamp jaw is driven forward by a constant force current; if the current reference speed is detected to drop to a second preset value, the state machine is switched to the reduced force pushing state; Step 82, when the state machine is in the reduced force pushing state, the electric clamp jaw is driven forward by a reduced force current which is linearly reduced; when the feedback speed of the electric clamp jaw is detected to be less than the first preset value, the state machine enters the back to normal mode state.

7. The control method according to claim 5, characterized by, The reference speed is a speed command value set by the control system and expected to be reached by the electric clamp jaw; the feedback speed is speed information fed back to the control system in real time during actual operation of the electric clamp jaw; and the reference current value is a current reference value set by the control system.

8. The control method according to claim 6, characterized by, The maximum speed threshold value is a maximum operating speed set during operation of the electric clamp jaw; the third preset value is 0.25 times the maximum speed threshold value; the second preset value is 0.35 times the maximum rebound speed; and the maximum rebound speed is the maximum speed that can be reached during the rebound process after the electric clamp jaw reaches the deepest collision position.

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