Clamping control method, device and computer readable storage medium of electric clamping jaw

Abstract

This application discloses a clamping control method, device, and computer-readable storage medium for an electric gripper, relating to the field of electric gripper technology. The method includes: dynamically acquiring the value of a continuous characterization variable representing the contact state between the electric gripper and the workpiece, wherein the continuous characterization variable changes continuously with the degree of contact between the electric gripper and the workpiece; generating a target stiffness coefficient corresponding to the electric gripper at the current moment based on the value of the continuous characterization variable, wherein the target stiffness coefficient is positively correlated with the value of the continuous characterization variable; inputting the target stiffness coefficient into the impedance control model of the electric gripper to obtain a first force control command for the electric gripper; and driving the electric gripper to perform a clamping action based on the first force control command. This application can reasonably set the clamping force of the electric gripper to avoid damaging the workpiece and ensure clamping stability.

Description

Technical Field

[0001] This application relates to the field of electric gripper technology, and in particular to a gripping control method, device and computer-readable storage medium for an electric gripper. Background Technology

[0002] Electric grippers, as core end effectors in robots and automation equipment, are widely used in tasks such as workpiece gripping, handling, and assembly. In gripping control, the precision of the contact force between the electric gripper and the workpiece directly affects workpiece quality and operation success rate. For fragile or soft workpieces, excessive gripping force can cause damage; for smooth or heavy workpieces, insufficient gripping force can easily lead to slippage and detachment.

[0003] Currently, the clamping control of electric grippers is usually achieved by detecting whether the electric gripper is in contact with the workpiece using a contact sensor. This divides the clamping control process into multiple discrete states (such as contact and clamping) and sets fixed clamping control parameters for different states to achieve clamping control of the electric gripper. Alternatively, a fixed clamping control parameter can be set directly to achieve clamping control of the electric gripper.

[0004] However, these methods cause the clamping force to rise too quickly during the initial contact stage, which can easily damage the workpiece; and during the steady-state clamping stage, they are difficult to adapt to changes in different workpiece materials and surface properties, resulting in large fluctuations in clamping force and poor clamping stability. Summary of the Invention

[0005] The main objective of this application is to provide a clamping control method, device, and computer-readable storage medium for an electric gripper, which aims to reasonably set the clamping force of the electric gripper to avoid damaging the workpiece and ensure clamping stability.

[0006] This application provides a gripping control method for an electric gripper, the method comprising: The variable values ​​of a continuous characterization variable of the contact state between the electric gripper and the workpiece are dynamically acquired, wherein the continuous characterization variable of the contact state changes continuously with the degree of contact between the electric gripper and the workpiece; Based on the variable values ​​of the continuous characterization variables of the contact state, a target stiffness coefficient corresponding to the current moment of the electric gripper is generated, wherein the target stiffness coefficient is positively correlated with the variable values ​​of the continuous characterization variables of the contact state; The target stiffness coefficient is input into the impedance control model of the electric gripper to obtain the first force control command of the electric gripper. Based on the first force control command, the electric gripper is driven to perform a gripping action.

[0007] In one embodiment, the step of generating the target stiffness coefficient corresponding to the current moment of the electric gripper based on the variable values ​​of the continuous characterization variables of the contact state includes: A preset monotonic continuous mapping function is used to map the variable values ​​of the continuous characterization variables of the contact state to stiffness adjustment coefficients. The monotonic continuous mapping function includes a slope parameter, which is used to adjust the steepness of the transition of the stiffness adjustment coefficients as the variable values ​​of the continuous characterization variables of the contact state change. Based on the stiffness adjustment coefficient, the preset maximum stiffness coefficient and minimum stiffness coefficient of the electric gripper, the candidate stiffness coefficient corresponding to the electric gripper at the current moment is calculated. Based on the candidate stiffness coefficients, the target stiffness coefficient corresponding to the electric gripper at the current moment is determined.

[0008] In one embodiment, the step of determining the target stiffness coefficient corresponding to the electric gripper at the current moment based on the candidate stiffness coefficients includes: Calculate the absolute difference between the candidate stiffness coefficient and the target stiffness coefficient determined at the previous moment to obtain the change in stiffness coefficient; If the change in stiffness coefficient is greater than a preset stiffness change threshold, then the candidate stiffness coefficient is adjusted according to the preset stiffness change threshold to obtain the target stiffness coefficient corresponding to the electric gripper at the current moment. If the change in stiffness coefficient is less than or equal to the preset stiffness change threshold, then the candidate stiffness coefficient is used as the target stiffness coefficient corresponding to the electric gripper at the current moment.

[0009] In one embodiment, the step of determining the target stiffness coefficient corresponding to the electric gripper at the current moment based on the candidate stiffness coefficients includes: The candidate stiffness coefficients are filtered using a first-order low-pass filter model to obtain the target stiffness coefficients corresponding to the electric gripper at the current moment. The first-order low-pass filter model satisfies the following: the difference between the target stiffness coefficient determined at the current moment and the target stiffness coefficient determined at the previous moment is equal to the difference between the candidate stiffness coefficient and the target stiffness coefficient determined at the previous moment multiplied by a preset filter coefficient.

[0010] In one embodiment, after the step of generating the target stiffness coefficient corresponding to the current moment of the electric gripper based on the variable values ​​of the continuous characterization variables of the contact state, the method further includes: The rate of change of a continuous characterization variable representing the contact state between the electric gripper and the workpiece is dynamically acquired. Based on the rate of change of the continuous characteristic variable of the contact state, a target damping coefficient corresponding to the current moment of the electric gripper is generated, wherein the target damping coefficient is positively correlated with the absolute value of the rate of change of the continuous characteristic variable of the contact state; The target damping coefficient and the target stiffness coefficient are input into the impedance control model of the electric gripper to obtain the second force control command of the electric gripper. Based on the second force control command, the electric gripper is driven to perform a gripping action.

[0011] In one embodiment, the step of generating the target damping coefficient corresponding to the current moment of the electric gripper based on the rate of change of the continuous characterization variable of the contact state includes: The damping gain is obtained by multiplying the absolute value of the rate of change of the continuous characteristic variable of the contact state with a preset gain coefficient. Calculate the sum between the damping gain and the basic damping coefficient of the electric gripper to obtain the candidate damping coefficient corresponding to the electric gripper at the current moment; Based on the candidate damping coefficients, the target damping coefficient corresponding to the current moment of the electric gripper is determined.

[0012] In one embodiment, the step of determining the target damping coefficient corresponding to the current moment of the electric gripper based on the candidate damping coefficients includes: Calculate the absolute difference between the candidate damping coefficient and the target damping coefficient determined at the previous moment to obtain the change in damping coefficient; If the change in the damping coefficient is greater than a preset damping change threshold, then the candidate damping coefficient is adjusted according to the preset damping change threshold to obtain the target damping coefficient corresponding to the electric gripper at the current moment. If the change in the damping coefficient is less than or equal to the preset damping change threshold, then the candidate damping coefficient is taken as the target damping coefficient corresponding to the current moment of the electric gripper.

[0013] In one embodiment, before the step of inputting the target stiffness coefficient into the impedance control model of the electric gripper to obtain the first force control command of the electric gripper, the method further includes: Dynamically acquire the slip strength index between the electric gripper and the workpiece; If the slip strength index is less than the preset index threshold, then the step of inputting the target stiffness coefficient into the impedance control model of the electric gripper to obtain the first force control command of the electric gripper is executed. If the slip strength index is greater than or equal to the preset index threshold, then the preset flexible stiffness coefficient of the electric gripper is input into the impedance control model of the electric gripper to obtain the third force control command of the electric gripper. Based on the third force control command, the electric gripper is driven to perform a gripping action.

[0014] In addition, to achieve the above objectives, this application also provides a control device, the control device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the clamping control method of the electric gripper as described above.

[0015] In addition, to achieve the above objectives, this application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the clamping control method of the electric gripper as described above.

[0016] This application provides a clamping control method for an electric gripper, comprising: dynamically acquiring the variable values ​​of a continuous characterization variable of the contact state between the electric gripper and the workpiece, wherein the continuous characterization variable of the contact state changes continuously with the degree of contact between the electric gripper and the workpiece; generating a target stiffness coefficient corresponding to the electric gripper at the current moment based on the variable values ​​of the continuous characterization variable of the contact state, wherein the target stiffness coefficient is positively correlated with the variable values ​​of the continuous characterization variable of the contact state; inputting the target stiffness coefficient into the impedance control model of the electric gripper to obtain a first force control command for the electric gripper; and driving the electric gripper to perform a clamping action based on the first force control command.

[0017] Therefore, the technical solution provided in this application dynamically acquires the variable values ​​of the characterizing variables that continuously change with the degree of contact, and generates a target stiffness coefficient that changes positively with it. This allows the stiffness of the electric gripper to adapt smoothly and in real time to the entire process from initial contact to stable clamping. Then, by using the target stiffness coefficient determined in real time through an impedance control model, a corresponding force control command is output, thereby achieving continuous and adaptive adjustment of the clamping force. Thus, the technical solution provided in this application can reasonably set the clamping force of the electric gripper, avoiding damage to the workpiece due to excessively rapid increase in clamping force caused by sudden stiffness changes in the initial contact stage, and ensuring stable and reliable clamping force in the steady-state clamping stage, thereby effectively improving clamping stability. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic flowchart of the clamping control method of the electric gripper provided in the first embodiment of this application; Figure 2 A graph showing how the stiffness coefficient changes as the contact state continuously characterizes the variable values, as provided in the first embodiment of this application. Figure 3 A schematic flowchart illustrating the clamping control method of the electric gripper provided in the second embodiment of this application; Figure 4 A schematic flowchart of the clamping control method of the electric gripper provided in the third embodiment of this application; Figure 5 This is a schematic diagram of the hardware operating environment involved in the embodiments of this application.

[0021] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0022] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0023] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0024] Electric grippers, as core end effectors in robots and automation equipment, are widely used in tasks such as workpiece gripping, handling, and assembly. In gripping control, the precision of the contact force between the electric gripper and the workpiece directly affects workpiece quality and operation success rate. For fragile or soft workpieces, excessive gripping force can cause damage; for smooth or heavy workpieces, insufficient gripping force can easily lead to slippage and detachment.

[0025] Currently, the clamping control of electric grippers is usually achieved by detecting whether the electric gripper is in contact with the workpiece using a contact sensor. This divides the clamping control process into multiple discrete states (such as contact and clamping) and sets fixed clamping control parameters for different states to achieve clamping control of the electric gripper. Alternatively, a fixed clamping control parameter can be set directly to achieve clamping control of the electric gripper.

[0026] However, these methods cause the clamping force to rise too quickly during the initial contact stage, which can easily damage the workpiece; and during the steady-state clamping stage, they are difficult to adapt to changes in different workpiece materials and surface properties, resulting in large fluctuations in clamping force and poor clamping stability.

[0027] Based on this, this application provides a clamping control method for an electric gripper, comprising: dynamically acquiring the variable values ​​of a continuous characterization variable of the contact state between the electric gripper and the workpiece, wherein the continuous characterization variable of the contact state changes continuously with the degree of contact between the electric gripper and the workpiece; generating a target stiffness coefficient corresponding to the electric gripper at the current moment based on the variable values ​​of the continuous characterization variable of the contact state, wherein the target stiffness coefficient is positively correlated with the variable values ​​of the continuous characterization variable of the contact state; inputting the target stiffness coefficient into the impedance control model of the electric gripper to obtain a first force control command for the electric gripper; and driving the electric gripper to perform a clamping action based on the first force control command.

[0028] Therefore, the technical solution provided in this application dynamically acquires the variable values ​​of the characterizing variables that continuously change with the degree of contact, and generates a target stiffness coefficient that changes positively with it. This allows the stiffness of the electric gripper to adapt smoothly and in real time to the entire process from initial contact to stable clamping. Then, by using the target stiffness coefficient determined in real time through an impedance control model, a corresponding force control command is output, thereby achieving continuous and adaptive adjustment of the clamping force. Thus, the technical solution provided in this application can reasonably set the clamping force of the electric gripper, avoiding damage to the workpiece due to excessively rapid increase in clamping force caused by sudden stiffness changes in the initial contact stage, and ensuring stable and reliable clamping force in the steady-state clamping stage, thereby effectively improving clamping stability.

[0029] The execution subject of the clamping control method of the electric gripper in this application can be a control device with data processing, network communication and program operation functions, or it can be an electric gripper control system including the control device. This embodiment does not specifically limit it in this regard.

[0030] The following description uses an electric gripper control system as the main actuator to illustrate the various embodiments.

[0031] This application presents a clamping control method for an electric gripper according to a first embodiment. Please refer to [link / reference]. Figure 1 The clamping control method of the electric gripper may include steps S10 to S40: Step S10: Dynamically acquire the variable values ​​of the continuous characterization variables of the contact state between the electric gripper and the workpiece, wherein the continuous characterization variables of the contact state change continuously with the degree of contact between the electric gripper and the workpiece. It should be noted that an electric gripper refers to an actuator driven by a motor that can perform opening and closing actions to clamp or release a workpiece. The continuous contact state characterization variable is a scalar parameter that continuously changes with the degree of contact between the electric gripper and the workpiece (e.g., from complete separation to slight contact, and then to stable clamping), and its value is usually within a preset range (e.g., 0 to 1). The variable value of the continuous contact state characterization variable refers to the specific value of the continuous contact state characterization variable at a certain sampling moment. Dynamic acquisition refers to acquiring data in real time during the clamping process at a certain control cycle (e.g., less than 1 millisecond).

[0032] In one feasible implementation, when dynamically acquiring the variable values ​​of the continuous characterization variables of the contact state between the electric gripper and the workpiece, the contact index and the sliding strength index between the electric gripper and the workpiece can be dynamically acquired, and then the contact index and the sliding strength index can be fused based on a preset fusion coefficient using Formula 1 as shown below to obtain the variable values ​​of the continuous characterization variables of the contact state.

[0033] The preset fusion coefficient can be a default value or can be flexibly set by the user according to the actual situation; this embodiment does not impose specific limitations on this. The contact index is used to quantify the degree of contact or proximity between the electric gripper and the workpiece. It reflects whether the electric gripper has contacted the workpiece, and the magnitude of the applied force or the proportion of the contact area after contact. It can be directly measured by force sensors, tactile sensors, or pressure sensors. The slippage strength index is used to quantify the degree of relative slippage or the risk of slippage between the electric gripper and the workpiece. It reflects whether the workpiece has a tendency to slide relative to the electric gripper or has already slipped during the clamping process. It can be determined by analyzing the vibration amplitude on the electric gripper or by detecting the fluctuation amplitude of the contact force between the electric gripper and the workpiece.

[0034] Formula 1; in, The value of the variable representing the continuous contact state at time t is given. Let be the contact index at time t. The slip strength index at time t. This is the preset fusion coefficient.

[0035] This embodiment does not specifically limit the implementation of step S10. For example, in other feasible embodiments, the variable value of the continuous characterizing variable of the contact state between the electric gripper and the workpiece can also be determined using the current signal of the electric gripper drive motor and the speed or position signal fed back by the encoder. Specifically, when the electric gripper contacts the workpiece, the motor load increases and the current rises; at the same time, the encoder detects a speed change or position stagnation. By comparing the current increment with a preset threshold and combining it with the encoder speed change rate, a continuously changing contact state characterizing variable can be fitted. For example, the ratio of the current increment to the maximum stall current can be mapped to a value between 0 and 1. This embodiment does not require additional sensor installation, has low cost, and fast response speed.

[0036] Step S20: Based on the variable values ​​of the continuous characterization variables of the contact state, generate the target stiffness coefficient corresponding to the electric gripper at the current moment, wherein the target stiffness coefficient is positively correlated with the variable values ​​of the continuous characterization variables of the contact state. It should be noted that the current moment refers to the current sampling moment within the control cycle, corresponding to the same moment in step S10 when the variable values ​​of the continuous characterization variables of the contact state are obtained. The target stiffness coefficient corresponding to the current moment of the electric gripper refers to the expected stiffness value that the electric gripper should possess at the current moment to achieve stable and rapid clamping without damaging the workpiece. The stiffness coefficient determines the electric gripper's ability to resist elastic deformation; a larger value indicates greater "rigidity," and a smaller value indicates greater "compliance." The target stiffness coefficient is positively correlated with the variable values ​​of the continuous characterization variables of the contact state; that is, the larger the variable values ​​of the continuous characterization variables of the contact state, the larger the target stiffness coefficient; and the smaller the variable values ​​of the continuous characterization variables of the contact state, the smaller the target stiffness coefficient.

[0037] In one feasible implementation, step S20 may include steps S21 to S23: Step S21: Using a preset monotonic continuous mapping function, the variable values ​​of the continuous characterization variables of the contact state are mapped to stiffness adjustment coefficients. The monotonic continuous mapping function includes a slope parameter, which is used to adjust the steepness of the transition of the stiffness adjustment coefficient as the variable values ​​of the continuous characterization variables of the contact state change. It should be noted that the monotonic continuous mapping function can be an S-shaped (Sigmoid) function or an exponential function as shown in Formula 2, etc., and this embodiment does not specifically limit it. The function of the monotonic continuous mapping function is to establish the mapping relationship between the variable values ​​of the continuous characterization variables of the contact state and the stiffness adjustment coefficient. The value range of the stiffness adjustment coefficient is usually [0, 1], which is used to represent the stiffness ratio to be selected in the current contact state (0 corresponds to minimum stiffness, 1 corresponds to maximum stiffness). The slope parameter is an adjustable parameter in the monotonic continuous mapping function, used to control the steepness of the function curve. The larger the slope parameter, the more drastic the change of the dependent variable with the independent variable near the middle value; the smaller the slope parameter, the smoother the change. In practical use, the slope parameter can be determined according to the fragility of the workpiece, the mechanical response speed of the electric gripper, and the rigidity requirements of the clamping task. For example, for fragile workpieces, a smaller slope parameter can be selected to make the stiffness coefficient transition smoothly; for robust workpieces, a larger slope parameter can be selected to make the stiffness coefficient establish quickly. In addition, the slope parameter can also be obtained through offline experimental calibration or online adaptive adjustment, and this embodiment does not specifically limit this.

[0038] Formula 2; in, This is the stiffness adjustment factor. Let S0 be the value of the variable representing the continuous contact state at time t, k be the slope parameter, and S0 be the tuned transition midpoint. The transition midpoint is usually set to 0.5, but in actual use, it can be flexibly adjusted according to the workpiece conditions. For example, for extremely soft workpieces, it can be set to 0.2; for brittle workpieces, it can be set to 0.8.

[0039] Step S22: Calculate the candidate stiffness coefficient corresponding to the electric gripper at the current moment based on the stiffness adjustment coefficient, the preset maximum stiffness coefficient, and the minimum stiffness coefficient of the electric gripper. It should be noted that the preset maximum stiffness coefficient of the electric gripper is the maximum allowable stiffness value, which usually corresponds to the expected stiffness under stable gripping conditions. The preset minimum stiffness coefficient of the electric gripper is the minimum stiffness value that the electric gripper should have when not in contact or just in contact. It is usually set to a small positive number to ensure compliance and avoid impact.

[0040] When calculating the candidate stiffness coefficient corresponding to the electric gripper at the current moment based on the stiffness adjustment coefficient, the preset maximum stiffness coefficient and minimum stiffness coefficient of the electric gripper, the specific calculation process can be expressed as the following formula 3.

[0041] Formula 3; in, Let be the candidate stiffness coefficient at time t. The maximum stiffness coefficient, This is the minimum stiffness coefficient. This is the stiffness adjustment factor.

[0042] Step S23: Determine the target stiffness coefficient corresponding to the electric gripper at the current moment based on the candidate stiffness coefficients.

[0043] In this embodiment, a preset monotonically continuous mapping function is first used to map the values ​​of the variables representing the continuous contact state to stiffness adjustment coefficients. The slope parameter included in the mapping function is then used to adjust the steepness of the transition of the stiffness adjustment coefficients as the contact depth changes. Next, candidate stiffness coefficients are calculated based on the stiffness adjustment coefficients and preset maximum and minimum stiffness coefficients of the electric gripper. Finally, the target stiffness coefficient for the current moment is determined based on the candidate stiffness coefficients. This achieves a smooth mapping of the target stiffness coefficient of the electric gripper with a continuous and adjustable steepness as the contact depth changes. This ensures that low stiffness is used in the initial contact phase to prevent workpiece damage, while allowing for a smooth or rapid transition to high stiffness as needed after the contact deepens to ensure stable clamping. This provides a stiffness input that precisely corresponds to the contact state for the subsequent impedance control model.

[0044] This embodiment does not specifically limit the implementation of step S20. For example, in other feasible implementations, the stiffness coefficients corresponding to the variable values ​​of continuous characterizing variables under different contact states can be recorded in advance and recorded using a relational table. Thus, the target stiffness coefficient can be quickly determined by looking up the table.

[0045] Furthermore, when determining the target stiffness coefficient corresponding to the electric gripper at the current moment based on the candidate stiffness coefficients, in the first feasible implementation, the candidate stiffness coefficients can be directly used as the target stiffness coefficient corresponding to the electric gripper at the current moment. In the second feasible implementation, step S23 may include steps S231~S233: Step S231: Calculate the absolute difference between the candidate stiffness coefficient and the target stiffness coefficient determined at the previous moment to obtain the change in stiffness coefficient; Step S232: If the change in stiffness coefficient is greater than the preset stiffness change threshold, then adjust the candidate stiffness coefficient according to the preset stiffness change threshold to obtain the target stiffness coefficient corresponding to the electric gripper at the current moment. It should be noted that the preset stiffness change threshold is the pre-set, allowed maximum stiffness change in a single step. It can be a default value or can be flexibly set by the user according to the actual situation. This embodiment does not make specific limitations on it.

[0046] When adjusting the candidate stiffness coefficients according to a preset stiffness change threshold to obtain the target stiffness coefficient corresponding to the electric gripper at the current moment, in one feasible implementation, if the candidate stiffness coefficient is greater than the target stiffness coefficient determined at the previous moment, the candidate stiffness coefficient can be directly adjusted to the sum of the target stiffness coefficient determined at the previous moment and the preset stiffness change threshold; if the candidate stiffness coefficient is less than the target stiffness coefficient determined at the previous moment, the candidate stiffness coefficient can be directly adjusted to the difference between the target stiffness coefficient determined at the previous moment and the preset stiffness change threshold. In another feasible implementation, the difference between the candidate stiffness coefficient and the target stiffness coefficient determined at the previous moment can be calculated first to obtain the stiffness coefficient difference; then, the product of the stiffness coefficient difference and the preset limiting coefficient is added to the target stiffness coefficient determined at the previous moment to obtain the target stiffness coefficient corresponding to the electric gripper at the current moment; wherein, the preset limiting coefficient can be a default value or can be flexibly set by the user according to the actual situation, and this embodiment does not specifically limit it.

[0047] Step S233: If the change in stiffness coefficient is less than or equal to the preset stiffness change threshold, then the candidate stiffness coefficient is used as the target stiffness coefficient corresponding to the electric gripper at the current moment.

[0048] In this embodiment, the absolute difference between the candidate stiffness coefficient and the target stiffness coefficient at the previous moment is first calculated to quantify the change range. Then, the quantified stiffness coefficient change is compared with a preset stiffness change threshold. If the stiffness coefficient change is greater than the preset stiffness change threshold, the candidate stiffness coefficient is adjusted according to the preset stiffness change threshold to limit its change range, thus obtaining the target stiffness coefficient at the current moment. If the stiffness coefficient change is less than or equal to the preset stiffness change threshold, the candidate stiffness coefficient can be directly used as the target stiffness coefficient at the current moment. Therefore, this embodiment realizes active monitoring and constraint of the single-step change of stiffness coefficient, ensuring that the change range of the target stiffness coefficient between adjacent control cycles does not exceed the preset safety upper limit, thereby effectively suppressing the impact of electric clamping force caused by sudden stiffness changes, making the electric gripper movement smoother and more compliant, and reducing the risk of damage to fragile workpieces.

[0049] In a third feasible implementation, step S23 may include: using a first-order low-pass filter model to filter the candidate stiffness coefficients to obtain the target stiffness coefficient corresponding to the electric gripper at the current moment; wherein, the first-order low-pass filter model satisfies: the difference between the target stiffness coefficient determined at the current moment and the target stiffness coefficient determined at the previous moment is equal to the difference between the candidate stiffness coefficient and the target stiffness coefficient determined at the previous moment multiplied by a preset filter coefficient.

[0050] It should be noted that the first-order low-pass filter model is a signal processing model used to smooth the input signal and suppress high-frequency abrupt changes. Its basic characteristic is that the rate of change of the output signal is proportional to the deviation between the input and output signals. In this embodiment, the first-order low-pass filter model is used to filter the candidate stiffness coefficient, ensuring that the target stiffness coefficient does not abruptly but smoothly approaches the candidate stiffness coefficient. The preset filter coefficient is a constant between 0 and 1, used to control the filtering strength. The larger the filter coefficient, the faster the target stiffness coefficient approaches the candidate stiffness coefficient, and the weaker the smoothing effect; the smaller the filter coefficient, the slower the target stiffness coefficient approaches the candidate stiffness coefficient, and the stronger the smoothing effect. This filter coefficient can be preset according to the response speed of the electric gripper and the fragility of the workpiece; this embodiment does not impose specific limitations on this.

[0051] The first-order low-pass filter model can be exemplarily represented as Equation 4 below.

[0052] Formula 4; in, Let be the candidate stiffness coefficient at time t. Let be the target stiffness coefficient at time t. The target stiffness coefficient at time t-1 These are the filter coefficients.

[0053] This implementation employs a first-order low-pass filter model to filter candidate stiffness coefficients to obtain the target stiffness coefficient at the current moment. The difference between the current target stiffness coefficient and the target stiffness coefficient at the previous moment is equal to the difference between the candidate stiffness coefficient and the target stiffness coefficient determined at the previous moment multiplied by a preset filter coefficient. This allows the target stiffness coefficient to smoothly approach the candidate stiffness coefficient in an exponential decay manner, avoiding stiffness jumps caused by direct assignment of abrupt changes in the candidate stiffness coefficient. Thus, a continuous and smooth transition of the target stiffness coefficient is achieved, effectively suppressing clamping force impacts and reducing the risk of damage to fragile workpieces. Furthermore, the preset filter coefficient can be adjusted to flexibly balance the smoothing effect and response speed, adapting to the needs of different workpiece materials and clamping tasks.

[0054] The above are only three feasible implementation methods of step S23 provided in this embodiment. This embodiment does not specifically limit the implementation method of step S23.

[0055] It is understood that, under the action of this embodiment, the stiffness coefficient used in the impedance control model can continuously change in real time following the variable value of the continuous characterization variable of the contact state. The specific change curve can be exemplarily referred to. Figure 2 The solid line A shown is... Figure 2The dashed line B in the figure represents the discrete variation of the stiffness coefficient. When the stiffness coefficient varies discretely, abrupt changes can easily trigger impacts.

[0056] Step S30: Input the target stiffness coefficient into the impedance control model of the electric gripper to obtain the first force control command of the electric gripper. It should be noted that the impedance control model is a control model used to describe the dynamic relationship between the end position error of the electric gripper and the contact force. In this embodiment, the impedance control model uses at least the target stiffness coefficient at the current moment as an input parameter, and combines it with the current position error of the electric gripper (i.e., the deviation between the reference position and the actual position) to calculate the desired output force value. The impedance control model in this embodiment can be simplified to the relationship shown in Equation 5 below.

[0057] Formula 5; Where F is the estimated contact force. Let X be the target stiffness coefficient at time t, and X be the actual position. ref For reference position.

[0058] Additionally, it should be noted that the first force control command refers to the force control command generated by the impedance control model based on the target stiffness coefficient. The contact force represented by this command is the estimated contact force calculated by the impedance control model based on the target stiffness coefficient.

[0059] Step S40: Based on the first force control command, drive the electric gripper to perform the gripping action.

[0060] As can be seen from the above, the technical solution provided in this embodiment dynamically acquires the variable values ​​of the characterizing variables that continuously change with the degree of contact, and generates a target stiffness coefficient that changes positively with it. This allows the stiffness of the electric gripper to adapt smoothly and in real time to the entire process from initial contact to stable clamping. Then, by using the target stiffness coefficient determined in real time through an impedance control model, a corresponding force control command is output, thereby achieving continuous and adaptive adjustment of the clamping force. Therefore, the technical solution provided in this embodiment can reasonably set the clamping force of the electric gripper, avoiding damage to the workpiece due to excessively rapid increase in clamping force caused by sudden changes in stiffness during the initial contact stage, and ensuring stable and reliable clamping force during the steady-state clamping stage, thus effectively improving clamping stability.

[0061] Based on the first embodiment described above, a second embodiment of the clamping control method for the electric gripper of this application is proposed. For the second embodiment, please refer to... Figure 3 After step S20, the clamping control method of the electric gripper may further include steps S50 to S80: Step S50: Dynamically acquire the rate of change of the continuous characterization variable of the contact state between the electric gripper and the workpiece; It should be noted that the rate of change of the continuous characterization variable of the contact state refers to the rate at which the value of the continuous characterization variable of the contact state changes over time, and is usually expressed as the amount of change of the continuous characterization variable of the contact state per unit time.

[0062] Step S60: Based on the rate of change of the continuous characterization variable of the contact state, generate the target damping coefficient corresponding to the electric gripper at the current moment, wherein the target damping coefficient is positively correlated with the absolute value of the rate of change of the continuous characterization variable of the contact state. It should be noted that the target damping coefficient of the electric gripper at the current moment refers to the expected damping value that the electric gripper should possess to achieve stable gripping at that moment. The damping coefficient determines the electric gripper's ability to resist changes in velocity; a larger value indicates greater motion resistance and faster dissipation of oscillation energy; a smaller value indicates less motion resistance and a more sensitive response. The target damping coefficient is positively correlated with the absolute value of the rate of change of the continuous characteristic variable of the contact state; that is, the larger the absolute value of the rate of change of the continuous characteristic variable of the contact state, the larger the target damping coefficient; the smaller the absolute value of the rate of change of the continuous characteristic variable of the contact state, the smaller the target damping coefficient.

[0063] In one feasible implementation, step S60 may include steps S61 to S63: Step S61: Calculate the product between the absolute value of the rate of change of the continuous characterization variable of the contact state and the preset gain coefficient to obtain the damping gain. It should be noted that the preset gain coefficient is a pre-set coefficient used to adjust the influence of the rate of change on the damping coefficient. It can be a default value or it can be flexibly set by the user according to the actual situation. This embodiment does not make specific limitations on this.

[0064] Step S62: Calculate the sum between the damping gain and the basic damping coefficient of the electric gripper to obtain the candidate damping coefficient corresponding to the electric gripper at the current moment. It should be noted that the basic damping coefficient refers to the reference damping value that the electric gripper should have when the rate of change of the continuously characterizing variable in the contact state is zero (i.e., the contact state is stable). It is usually set to a small positive number to ensure the system's response sensitivity in a steady state.

[0065] The calculation process of steps S61 to S62 above can be expressed as the following formula 6.

[0066] Formula 6; in, Let be the candidate damping coefficient at time t. Based on the basic damping coefficient, The preset gain coefficient, Let t be the absolute value of the rate of change of the contact state continuous characterizing variable at time t.

[0067] Step S63: Determine the target damping coefficient corresponding to the electric gripper at the current moment based on the candidate damping coefficients.

[0068] In this embodiment, the damping gain is first calculated by multiplying the absolute value of the rate of change of the continuous characteristic variable of the contact state with a preset gain coefficient. Then, the sum of the damping gain and the basic damping coefficient of the electric gripper is calculated to obtain the candidate damping coefficient corresponding to the electric gripper at the current moment. Finally, the final target damping coefficient is determined based on the candidate damping coefficient. This achieves linear adaptive adjustment of the damping coefficient according to the degree of change in the contact state: when the contact state changes slowly, the damping gain is small, the target damping coefficient is close to the basic damping coefficient, and the system maintains a sensitive response; when the contact state changes drastically, the damping gain increases, and the target damping coefficient increases accordingly, thereby enhancing the system's ability to suppress shocks and oscillations, further ensuring the stability of the gripping.

[0069] Furthermore, this implementation method requires no complex calculations; the damping coefficient can be dynamically generated simply through multiplication and summation operations, resulting in high computational efficiency.

[0070] This embodiment does not specifically limit the implementation of step S60. For example, in other feasible implementations, the damping coefficients corresponding to the rates of change of continuous characterizing variables under different contact states can be recorded in advance and recorded using a relational table. Thus, the target damping coefficient can be quickly determined by looking up the table.

[0071] Furthermore, when determining the target damping coefficient corresponding to the electric gripper at the current moment based on the candidate damping coefficients, in one feasible implementation, the candidate damping coefficients can be directly used as the target damping coefficient corresponding to the electric gripper at the current moment. In another feasible implementation, step S63 may include steps S631~S633: Step S631: Calculate the absolute difference between the candidate damping coefficient and the target damping coefficient determined at the previous moment to obtain the change in damping coefficient. Step S632: If the change in damping coefficient is greater than the preset damping change threshold, then adjust the candidate damping coefficient according to the preset damping change threshold to obtain the target damping coefficient corresponding to the electric gripper at the current moment. It should be noted that the preset damping change threshold is the pre-set, allowed maximum single-step damping change. It can be a default value or can be flexibly set by the user according to the actual situation. This embodiment does not impose specific limitations on it.

[0072] When adjusting the candidate damping coefficient according to the preset damping change threshold to obtain the target damping coefficient corresponding to the electric gripper at the current moment, in one feasible implementation, if the candidate damping coefficient is greater than the target damping coefficient determined at the previous moment, the candidate damping coefficient can be directly adjusted to the sum of the target damping coefficient determined at the previous moment and the preset damping change threshold; if the candidate damping coefficient is less than the target damping coefficient determined at the previous moment, the candidate damping coefficient can be directly adjusted to the difference between the target damping coefficient determined at the previous moment and the preset damping change threshold. In another feasible implementation, the difference between the candidate damping coefficient and the target damping coefficient determined at the previous moment can be calculated first to obtain the damping coefficient difference; then, the product of the damping coefficient difference and the preset limiting coefficient is added to the target damping coefficient determined at the previous moment to obtain the target damping coefficient corresponding to the electric gripper at the current moment; wherein, the preset limiting coefficient can be a default value or can be flexibly set by the user according to the actual situation, and this embodiment does not specifically limit it.

[0073] Step S633: If the change in damping coefficient is less than or equal to the preset damping change threshold, then the candidate damping coefficient is used as the target damping coefficient corresponding to the electric gripper at the current moment.

[0074] In this embodiment, the absolute difference between the candidate damping coefficient and the target damping coefficient at the previous moment is first calculated to quantify the change range. Then, the quantified change in damping coefficient is compared with a preset damping change threshold. If the change in damping coefficient is greater than the preset damping change threshold, the candidate damping coefficient is adjusted according to the preset damping change threshold to limit its change range, thus obtaining the target damping coefficient at the current moment. If the change in damping coefficient is less than or equal to the preset damping change threshold, the candidate damping coefficient is directly used as the target damping coefficient at the current moment. Therefore, this embodiment realizes active monitoring and constraint of the single-step change in damping coefficient, ensuring that the change range of the target damping coefficient between adjacent control cycles does not exceed the preset safety upper limit. This effectively suppresses the torque impact of the electric gripper caused by damping abrupt changes, making the electric gripper movement more stable, further reducing the risk of damage to the workpiece, and improving the stability of the clamping process.

[0075] The above are only two feasible implementation methods of step S63 provided in this embodiment. This embodiment does not specifically limit the implementation method of step S63.

[0076] Step S70: Input the target damping coefficient and target stiffness coefficient into the impedance control model of the electric gripper to obtain the second force control command of the electric gripper. It should be noted that the second force control command refers to the force control command generated by the impedance control model based on both the target stiffness coefficient and the target damping coefficient. The contact force represented by this command is the estimated contact force calculated by the impedance control model based on both the target stiffness coefficient and the target damping coefficient. In this embodiment, the impedance control model uses at least the target stiffness coefficient and the target damping coefficient at the current moment as input parameters, and combines them with the current position error of the electric gripper (i.e., the deviation between the reference position and the actual position) to calculate the desired output force value. The impedance control model in this embodiment can be expressed as the relationship shown in Equation 7 below.

[0077] Formula 7; Where F is the estimated contact force. Let X be the target stiffness coefficient at time t, and X be the actual position. ref For reference position, Let be the target damping coefficient at time t.

[0078] In step S80, based on the second force control command, the electric gripper is driven to perform a gripping action.

[0079] In this embodiment, the rate of change of the continuous characterizing variable of the contact state is first dynamically acquired. Then, a target damping coefficient positively correlated with the rate of change is generated. The target damping coefficient, along with the target stiffness coefficient, is then input into the impedance control model to obtain a second force control command. Finally, the gripper is driven to perform the clamping action based on this command. This achieves adaptive adjustment of the damping coefficient according to the degree of change in the contact state: when the contact state changes slowly, the damping coefficient is small, and the system maintains a fast response; when the contact state changes drastically, the damping coefficient automatically increases, effectively suppressing impact and oscillation. Compared to a scheme that only adjusts stiffness, this embodiment introduces dynamic damping adjustment to further enhance the compliance and stability of the electric gripper during the contact transient and slippage warning stages, reducing the probability of workpiece damage and slippage.

[0080] Based on the first and / or second embodiments described above, a third embodiment of the clamping control method for the electric gripper of this application is proposed. In the third embodiment, please refer to... Figure 4 Before step S30, the clamping control method of the electric gripper may also include steps S301 to S304: Step S301: Dynamically acquire the slip strength index between the electric gripper and the workpiece; Step S302: If the slip strength index is less than the preset index threshold, then the step of inputting the target stiffness coefficient into the impedance control model of the electric gripper is executed to obtain the first force control command of the electric gripper. It should be noted that the preset index threshold is a pre-set critical value of the slip strength index used to distinguish between normal clamping state and slip risk state. It can be a default value or it can be flexibly set by the user according to the actual situation. This embodiment does not make specific limitations on this.

[0081] Step S303: If the slip strength index is greater than or equal to the preset index threshold, the preset flexible stiffness coefficient of the electric gripper is input into the impedance control model of the electric gripper to obtain the third force control command of the electric gripper. It should be noted that the flexibility stiffness coefficient is a pre-set stiffness value that is less than and close to the minimum stiffness coefficient (usually set to 0.5 to 0.8 times the minimum stiffness coefficient). It is used to actively reduce the stiffness of the electric gripper when slippage occurs, thereby increasing the conformity of the grip. The third force control command refers to the force control command generated by the impedance control model based on the flexibility stiffness coefficient. The contact force represented by this command is the estimated contact force calculated by the impedance control model based on the flexibility stiffness coefficient.

[0082] Step S304: Based on the third force control command, drive the electric gripper to perform the gripping action.

[0083] In this embodiment, the slippage strength index between the electric gripper and the workpiece is first dynamically acquired, and then compared with a preset threshold value. If the slippage strength index is less than the preset threshold value, the normal gripping process is executed (a first force control command is generated using a target stiffness coefficient). If the slippage strength index is greater than or equal to the preset threshold value, the system switches to slippage correction mode, generates a third force control command using a preset flexible stiffness coefficient, and drives the gripper based on this command. This achieves real-time monitoring and rapid response to slippage events: maintaining normal adaptive gripping when there is no slippage or slight slippage; and immediately switching the stiffness coefficient to a more compliant value once the slippage strength reaches a dangerous level, causing the electric gripper to actively reduce its stiffness to suppress slippage and prevent workpiece detachment or damage. Therefore, this embodiment provides an additional safety protection mechanism while maintaining normal gripping performance, thereby effectively improving the robustness and safety of the gripping process.

[0084] This application also provides a control device, which may include: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the clamping control method of the electric gripper in the above embodiments.

[0085] The following is for reference. Figure 5 It shows a schematic diagram of the structure of a control device suitable for implementing the embodiments of this application. Figure 5The control device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0086] like Figure 5 As shown, the control device may include a processing unit 101 (e.g., a central processing unit, a graphics processing unit, etc.), which can perform various appropriate actions and processes according to a program stored in read-only memory 102 or a program loaded from storage device 103 into random access memory 104. Random access memory 104 also stores various programs and data required for the operation of the control device. The processing unit 101, read-only memory 102, and random access memory 104 are interconnected via bus 105. Input / output interface 106 is also connected to bus 105. Typically, the following systems can be connected to input / output interface 106: input devices 107 including, for example, touch screens, touchpads, keyboards, mice, image sensors, microphones, accelerometers, gyroscopes, etc.; output devices 108 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; storage devices 103 including, for example, magnetic tapes, hard disks, etc.; and communication devices 109. Communication device 109 allows the control device to communicate wirelessly or wiredly with other devices to exchange data. Although the diagram shows control equipment with various systems, it should be understood that it is not required to implement or have all of the systems shown. More or fewer systems may be implemented alternatively.

[0087] In particular, according to embodiments of this disclosure, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of this disclosure include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication device, or installed from storage device 103, or installed from read-only memory 102. When the computer program is executed by processing device 101, it performs the functions defined in the methods of the embodiments of this application.

[0088] The control device provided in this application embodiment employs the clamping control method of the electric gripper in the above embodiments, which can reasonably set the clamping force of the electric gripper to avoid damaging the workpiece and ensure clamping stability. Compared with the prior art, the beneficial effects of the control device provided in this application embodiment are the same as those of the clamping control method of the electric gripper provided in the above embodiments, and other technical features in this control device are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0089] It should be understood that various parts of the embodiments of this application can be implemented using hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0090] The above description is merely a specific implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of the embodiments of this application. Therefore, the protection scope of the embodiments of this application should be determined by the protection scope of the above claims.

[0091] This application also provides a computer-readable storage medium storing a computer program that can run on a processor. The computer program is used to execute the clamping control method of the electric gripper in the above embodiments.

[0092] The computer-readable storage medium provided in this application embodiment may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0093] The aforementioned computer-readable storage medium may be included in the control device; or it may exist independently and not assembled into the control device.

[0094] The aforementioned computer-readable storage medium carries one or more programs. When the aforementioned one or more programs are executed by the control device, the control device causes the control device to: dynamically acquire the variable values ​​of a continuous characterization variable of the contact state between the electric gripper and the workpiece, wherein the continuous characterization variable of the contact state changes continuously with the degree of contact between the electric gripper and the workpiece; generate a target stiffness coefficient corresponding to the electric gripper at the current moment based on the variable values ​​of the continuous characterization variable of the contact state, wherein the target stiffness coefficient is positively correlated with the variable values ​​of the continuous characterization variable of the contact state; input the target stiffness coefficient into the impedance control model of the electric gripper to obtain a first force control command for the electric gripper; and drive the electric gripper to perform a clamping action based on the first force control command.

[0095] Computer program code for performing the operations of this disclosure can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0096] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0097] The modules described in the embodiments of this application can be implemented in software or hardware. The names of the modules do not necessarily limit the functionality of the unit itself.

[0098] The computer-readable storage medium provided in this application embodiment stores computer-readable program instructions for executing the above-described electric gripper clamping control method, which can reasonably set the clamping force of the electric gripper to avoid damaging the workpiece and ensure clamping stability. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided in this application embodiment are the same as the beneficial effects of the electric gripper clamping control method provided in the above embodiments, and will not be repeated here.

[0099] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the clamping control method of the electric gripper as described above.

[0100] The computer program product provided in this application embodiment can reasonably set the clamping force of the electric gripper to avoid damaging the workpiece and ensure clamping stability. Compared with the prior art, the beneficial effects of the computer program product provided in this application embodiment are the same as the beneficial effects of the electric gripper clamping control method provided in the above embodiments, and will not be repeated here.

[0101] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A clamping control method of an electric gripper, characterized by, The method includes: The variable values ​​of a continuous characterization variable of the contact state between the electric gripper and the workpiece are dynamically acquired, wherein the continuous characterization variable of the contact state changes continuously with the degree of contact between the electric gripper and the workpiece; Based on the variable values ​​of the continuous characterization variables of the contact state, a target stiffness coefficient corresponding to the current moment of the electric gripper is generated, wherein the target stiffness coefficient is positively correlated with the variable values ​​of the continuous characterization variables of the contact state; The target stiffness coefficient is input into the impedance control model of the electric gripper to obtain the first force control command of the electric gripper. Based on the first force control command, the electric gripper is driven to perform a gripping action.

2. The method as described in claim 1, characterized in that, The step of generating the target stiffness coefficient corresponding to the current moment of the electric gripper based on the variable values ​​of the continuous characterization variables of the contact state includes: A preset monotonic continuous mapping function is used to map the variable values ​​of the continuous characterization variables of the contact state to stiffness adjustment coefficients. The monotonic continuous mapping function includes a slope parameter, which is used to adjust the steepness of the transition of the stiffness adjustment coefficients as the variable values ​​of the continuous characterization variables of the contact state change. Based on the stiffness adjustment coefficient, the preset maximum stiffness coefficient and minimum stiffness coefficient of the electric gripper, the candidate stiffness coefficient corresponding to the electric gripper at the current moment is calculated. Based on the candidate stiffness coefficients, the target stiffness coefficient corresponding to the electric gripper at the current moment is determined.

3. The method as described in claim 2, characterized in that, The step of determining the target stiffness coefficient corresponding to the electric gripper at the current moment based on the candidate stiffness coefficients includes: Calculate the absolute difference between the candidate stiffness coefficient and the target stiffness coefficient determined at the previous moment to obtain the change in stiffness coefficient; If the change in stiffness coefficient is greater than a preset stiffness change threshold, then the candidate stiffness coefficient is adjusted according to the preset stiffness change threshold to obtain the target stiffness coefficient corresponding to the electric gripper at the current moment. If the change in stiffness coefficient is less than or equal to the preset stiffness change threshold, then the candidate stiffness coefficient is used as the target stiffness coefficient corresponding to the electric gripper at the current moment.

4. The method as described in claim 2, characterized in that, The step of determining the target stiffness coefficient corresponding to the electric gripper at the current moment based on the candidate stiffness coefficients includes: The candidate stiffness coefficients are filtered using a first-order low-pass filter model to obtain the target stiffness coefficients corresponding to the electric gripper at the current moment. The first-order low-pass filter model satisfies the following: the difference between the target stiffness coefficient determined at the current moment and the target stiffness coefficient determined at the previous moment is equal to the difference between the candidate stiffness coefficient and the target stiffness coefficient determined at the previous moment multiplied by a preset filter coefficient.

5. The method according to any one of claims 1 to 4, characterized in that, After the step of generating the target stiffness coefficient corresponding to the current moment of the electric gripper based on the variable values ​​of the continuously characterizing variables of the contact state, the method further includes: The rate of change of a continuous characterization variable representing the contact state between the electric gripper and the workpiece is dynamically acquired. Based on the rate of change of the continuous characteristic variable of the contact state, a target damping coefficient corresponding to the current moment of the electric gripper is generated, wherein the target damping coefficient is positively correlated with the absolute value of the rate of change of the continuous characteristic variable of the contact state; The target damping coefficient and the target stiffness coefficient are input into the impedance control model of the electric gripper to obtain the second force control command of the electric gripper. Based on the second force control command, the electric gripper is driven to perform a gripping action.

6. The method as described in claim 5, characterized in that, The step of generating the target damping coefficient corresponding to the current moment of the electric gripper based on the rate of change of the continuous characterization variable of the contact state includes: The damping gain is obtained by multiplying the absolute value of the rate of change of the continuous characteristic variable of the contact state with a preset gain coefficient. Calculate the sum between the damping gain and the basic damping coefficient of the electric gripper to obtain the candidate damping coefficient corresponding to the electric gripper at the current moment; Based on the candidate damping coefficients, the target damping coefficient corresponding to the current moment of the electric gripper is determined.

7. The method as described in claim 6, characterized in that, The step of determining the target damping coefficient corresponding to the electric gripper at the current moment based on the candidate damping coefficients includes: Calculate the absolute difference between the candidate damping coefficient and the target damping coefficient determined at the previous moment to obtain the change in damping coefficient; If the change in the damping coefficient is greater than a preset damping change threshold, then the candidate damping coefficient is adjusted according to the preset damping change threshold to obtain the target damping coefficient corresponding to the electric gripper at the current moment. If the change in the damping coefficient is less than or equal to the preset damping change threshold, then the candidate damping coefficient is taken as the target damping coefficient corresponding to the current moment of the electric gripper.

8. The method according to any one of claims 1 to 4, characterized in that, Before the step of inputting the target stiffness coefficient into the impedance control model of the electric gripper to obtain the first force control command of the electric gripper, the method further includes: Dynamically acquire the slip strength index between the electric gripper and the workpiece; If the slip strength index is less than the preset index threshold, then the step of inputting the target stiffness coefficient into the impedance control model of the electric gripper to obtain the first force control command of the electric gripper is executed. If the slip strength index is greater than or equal to the preset index threshold, then the preset flexible stiffness coefficient of the electric gripper is input into the impedance control model of the electric gripper to obtain the third force control command of the electric gripper. Based on the third force control command, the electric gripper is driven to perform a gripping action.

9. A control device, characterized in that, The control device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the clamping control method of the electric gripper as described in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the clamping control method of the electric gripper as described in any one of claims 1 to 8.

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