A robot compliance control method and system

Abstract

The application discloses a kind of robot compliance control method and system, the determination method of effective external torque in the control method includes: obtaining joint desired acceleration, joint actual equivalent moment of inertia, original observation external torque, joint actual speed;Based on the preset safety gain coefficient, joint actual equivalent moment of inertia, inertia error compensation coefficient is calculated;Based on the preset static dead zone threshold, joint desired acceleration, inertia error compensation coefficient, dynamic dead zone threshold is calculated;According to joint actual speed, preset speed threshold, original observation external torque, preset friction noise tolerance band, determine effective reference torque;Based on effective reference torque, dynamic dead zone threshold, effective external torque is calculated.Using the present application can solve the industry common technical problems that trajectory rigid tracking and safe compliance interaction cannot be effectively compatible in robot impedance control technology.

Description

Technical Field

[0001] This invention belongs to the field of robot joint torque control and servo drive technology, specifically relating to a robot compliant control method and system. Background Technology

[0002] In recent years, robots with human-robot collaboration capabilities (such as collaborative robotic arms and humanoid robots) have been widely used. To ensure the safety and compliance of human-robot interaction, the industry typically employs sensorless external force estimation techniques based on momentum observers (MOBs) to enable robots to obediently retreat when subjected to external collisions or human dragging. In practical engineering applications, the original observed external torque estimated by the observer is highly susceptible to the influence of Gaussian white noise from current sensors, dynamic modeling errors, and internal friction. Therefore, to prevent malfunctions caused by internal noise, a dead zone (or deadband) must be introduced at the observer's output in the control system. A dead zone refers to a threshold range artificially set in the control logic; when the input external force observation signal falls within this range, the system forcibly outputs zero, thereby shielding against underlying noise interference.

[0003] However, existing robot compliance control methods have the following problems:

[0004] (1) False disturbance torque and unexpected yielding caused by mismatch in rotational inertia: The existing dead zone threshold is a fixed constant. During the rapid acceleration and deceleration phase of the robot joint, the equivalent nominal rotational inertia preset by the system and the actual equivalent rotational inertia of the joint under the current posture of the robot arm inevitably deviate. Since the fixed dead zone cannot cope with the significant false disturbance torque generated during the acceleration phase (i.e., the non-real external torque observation value caused by rotational inertia error), the observed torque easily breaks through the dead zone threshold when the robot is not subjected to any external interaction force, causing non-command pose jitter or unexpected erroneous yielding, which seriously reduces the trajectory tracking accuracy.

[0005] (2) High-frequency oscillation under load caused by low-speed nonlinear friction (limit cycle): The fixed dead zone is based on the absolute zero point, which is effective when the robot is running unloaded; however, when the robot is stationary under load (stopping over external weights or resistance) or in a state of extremely low-speed motion, the Coulomb friction of its internal reducer (such as a harmonic reducer) will undergo a violent nonlinear change near the zero point of the speed (i.e., the Stribeck effect). This change in friction will cause the momentum observer to frequently output external torque fluctuation errors, causing the control system to fall into a state of high-frequency micro-oscillation, which is manifested at the physical level as high-frequency electromagnetic noise and mechanical micro-vibration generated by the joint motor.

[0006] (3) Torque jump and mechanical shock caused by hard dead zone: Currently, the fixed dead zone control logic is: when the absolute value of the input signal is less than the dead zone threshold, the output is zero; once the absolute value of the input signal crosses the dead zone threshold, the original input signal is directly output. This logic will cause a step jump at the output equal to the size of the dead zone threshold at the instant the signal crosses the dead zone threshold (for example, the dead zone threshold is 10 ... When the external force reaches At that time, the output command instantly changed from Mutation to When such discontinuous torque commands are sent to the underlying joint servo driver, they can cause transient mechanical shocks (i.e., jerking sensations) in the joint mechanism, which can easily lead to fatigue damage to the reducer gears and seriously affect the smoothness of human-machine dragging interaction. Summary of the Invention

[0007] The purpose of this invention is to provide a robot compliant control method and system to solve the problem of false disturbances that trigger compliant control due to rotational inertia errors during the rapid acceleration and deceleration phase of a robot.

[0008] In a first aspect, the present invention provides a robot compliant control method, comprising: acquiring desired joint position, desired joint velocity, desired joint acceleration, and effective external torque; calculating and generating position / torque correction commands for compliant robot interaction actions based on the desired joint position, desired joint velocity, desired joint acceleration, effective external torque, and preset target impedance parameters; and executing underlying joint servo control and torque output according to the position / torque correction commands. The method for determining the effective external torque includes:

[0009] Obtain the expected acceleration of the joint, the actual equivalent moment of inertia of the joint, the original observed external torque, and the actual velocity of the joint.

[0010] The inertia error compensation coefficient is calculated based on the preset safety gain coefficient and the actual equivalent rotational inertia of the joint.

[0011] The dynamic dead zone threshold is calculated based on the preset static dead zone threshold, joint expected acceleration, and inertia error compensation coefficient.

[0012] The effective reference torque is determined based on the actual joint speed, the preset speed threshold, the original observed external torque, and the preset friction noise tolerance band.

[0013] The effective external torque is calculated based on the effective reference torque and the dynamic dead zone threshold.

[0014] By setting a static dead zone threshold and calculating a dynamic dead zone threshold in conjunction with the joint's desired acceleration and inertia error compensation coefficient, and adaptively adjusting the filtering threshold according to the real-time motion state, measurement noise and vibration interference caused by inertial coupling during high-speed or variable-speed motion are effectively filtered out. This solves the problem of false disturbances and erroneous triggering of compliant control caused by rotational inertia errors during the robot's rapid acceleration and deceleration phases. An inertia error compensation coefficient is introduced to correct model deviations caused by the actual equivalent rotational inertia, compensating for inertia mismatch caused by load changes or errors in dynamic parameter identification, and preventing false external force deviations due to inaccurate inertia estimation during acceleration and deceleration. The original observed external torque is screened and benchmarked using the joint's actual speed, a preset speed threshold, and a friction noise tolerance band. This removes nonlinear disturbances such as Coulomb friction during joint reversal and the Stribeck effect at low speeds from the external force signal, making the extracted effective benchmark torque more realistically reflect the external contact force, and achieving dynamic decoupling of the torque signal from friction disturbances. The effective external torque, after being processed by dynamic dead zone threshold denoising and friction tolerance screening, is input into the admittance / impedance controller to generate correction commands, so that the joint servo control output exhibits smoother damping characteristics. During collision response, it can maintain sensitivity without generating chatter, thereby achieving high-precision and high-stability smooth dragging or assembly operations.

[0015] Optionally, the method for determining the effective reference torque includes:

[0016] When the joint is at extremely low speed or stationary under load, the latching external torque for the current cycle is determined based on the original observed external torque of the current cycle, the latching external torque of the previous cycle, and the preset friction noise tolerance band.

[0017] When the joint is in a normal high-speed motion state, the original observed external torque of the current cycle is used as the latched external torque of the current cycle.

[0018] The latching external torque of the current cycle is used as the effective reference torque of the current cycle.

[0019] When the joint is at extremely low speed or stationary under load, the original observed external torque of the current cycle is compared and updated by introducing the latched external torque of the previous cycle and the preset friction noise tolerance band. This effectively utilizes historical cycle values ​​to buffer the inertial changes in friction force in the current cycle, avoiding physical oscillations caused by frequent controller adjustments. When the joint is in normal high-speed motion, the original observed external torque of the current cycle is directly used as the latched external torque of the current cycle. In the high-speed range where friction force tends to be stable and the signal-to-noise ratio is high, the filtering lag constraint under low-speed conditions is released (i.e., latching is released), ensuring that the phase of the external torque signal is not delayed and the amplitude is not attenuated, thereby maintaining the force response sensitivity and dynamic bandwidth of compliant control during rapid following.

[0020] Optional, if This indicates that the joint is at extremely low speed or in a loaded, stationary state; if This indicates that the joint is in a normal, high-speed movement state; among which, This indicates the actual speed of the joint in the current cycle. This represents the preset speed threshold. The system can quickly identify the friction-dominated and inertia-dominated zones based solely on the actual joint speed. The judgment logic is simple and meets the high real-time requirements within the servo cycle. Absolute value comparison eliminates directional interference. This judgment result provides precise state triggering conditions for the differentiated processing of effective reference torque under different working conditions.

[0021] Optionally, to address the limiting cycle oscillation caused by sudden changes in low-speed friction, a hysteresis filter and a state latch based on the current force state were designed. Therefore, when the joint is at extremely low speed or in a loaded, stationary state, the following formula is used: The latching external torque for the current cycle is calculated. ;in, This represents the original observed external torque for the current period. This indicates the latching external torque of the previous cycle. This represents the preset friction noise tolerance band. When the torque fluctuation amplitude is less than or equal to the preset friction noise tolerance band, the state latch from the previous cycle is forcibly maintained. This breaks the positive feedback loop of high-frequency interference caused by the sudden change in Stribeck friction force, avoiding physical oscillations caused by frequent controller adjustments. When the torque fluctuation amplitude exceeds the preset friction noise tolerance band, the latch is released. This solves the problem of high-frequency micro-oscillations (limit cycles) caused by nonlinear changes in low-speed friction force when the robot is at extremely low speeds or stationary under load.

[0022] Alternatively, use the formula: The inertia error compensation coefficient for the current cycle is calculated. Where k represents the preset safety gain coefficient, , This indicates the maximum absolute error limit for the current period. This ensures that the dynamically expanded dead zone can completely enclose the maximum spurious disturbance torque caused by inertia deviation.

[0023] Optionally, based on the actual equivalent moment of inertia of the joint in the current cycle, a preset maximum absolute error limit table is consulted to obtain the... The preset maximum absolute error limit table is a table showing the correspondence between the actual equivalent rotational inertia of the joint and the maximum absolute error limit obtained through calibration. Using a lookup table to obtain the maximum absolute error limit for the current cycle significantly reduces the computational load on the embedded controller during high-speed servo cycles, ensuring the real-time executability of the compensation process. The preset maximum absolute error limit table, established in advance through experimental calibration, accurately reflects the extreme values ​​of model mismatch under different load inertia, ensuring that the inertia error compensation coefficient always includes a safety margin under the worst-case deviation scenario.

[0024] Alternatively, use the formula: The dynamic dead zone threshold for the current cycle is calculated. .in, This represents the preset static dead zone threshold. This represents the inertia error compensation coefficient for the current cycle. This represents the expected acceleration of the joint in the current cycle. The underlying Gaussian white noise is used to shield the sensor. This is used when the robot is moving at a constant speed or stationary. The dynamic dead zone threshold falls back to a very small value. It maintains high tactile sensitivity; during the robot's rapid acceleration and deceleration phase, the dynamic dead zone threshold dynamically increases with the increase of the joint's expected acceleration (the dead zone interval widens), forming an adaptive anti-disturbance interval, which envelops and shields the false disturbance torque caused by inertia mismatch from the mathematical model level.

[0025] Optionally, to address the jump problem caused by the existing hard dead zone, a soft dead zone mapping is applied to the effective reference torque. A soft dead zone is a continuous, non-smooth, but step-free, nonlinear output mapping equation. Specifically, it is expressed as:

[0026] Using the formula:

[0027] The effective external torque of the current period is calculated. ;in, This represents the dynamic dead zone threshold for the current period. This represents the effective reference torque for the current cycle. Represents a symbolic function. When... hour, ;when hour, ;when hour, .

[0028] When the effective reference torque does not exceed the dynamic dead zone threshold, the output is strictly 0; when the effective reference torque exceeds the dynamic dead zone threshold, the full effective reference torque (i.e., the full input signal) is not directly output, but the dynamic dead zone threshold is actively subtracted from the input signal. This mechanism ensures that the effective external torque command output to the admittance / impedance controller is always from the dynamic dead zone threshold. Initially, it climbs steadily and continuously at a constant slope, solving the problem of torque step jump and mechanical shock caused by the existing hard dead zone when the signal crosses the dead zone threshold, thus ensuring the complete continuity of the external torque response.

[0029] Optionally, the method for determining the original observed external torque includes:

[0030] Obtain the actual joint position, actual joint velocity, and electromagnetic torque fed back by the motor;

[0031] Using the formula: The original observed external torque for the current period is calculated. ;in, This represents the preset momentum observer gain constant. This represents the preset equivalent nominal moment of inertia. This indicates the actual speed of the joint in the current cycle. This represents the actual velocity of the joint at the initial moment. This represents the electromagnetic feedback torque of the motor in the i-th cycle (i.e., the electromagnetic torque output by the motor). This represents the original observed external torque during the (i-1)th period. This represents the friction torque compensation in the i-th cycle. This represents the gravitational torque compensation in the i-th cycle. Indicates the system control cycle. This represents the actual joint velocity in the i-th cycle. according to Calculations show that This represents the actual position of the joint in the i-th cycle. according to Calculated.

[0032] Secondly, the present invention provides a robot compliance control system, including a memory and a processor, wherein the memory stores a computer program and the processor is configured to execute the computer program to implement the above-described robot compliance control method.

[0033] Compared with the prior art, the present invention has the following significant advantages and positive effects:

[0034] (1) It balances the rigidity of trajectory tracking with the flexibility of human-computer interaction. Through The algorithm enables the robot to dynamically expand the dead zone when executing high-speed, high-acceleration motion commands, maintain extremely high trajectory tracking rigidity, suppress unexpected retreat, and maintain a high level of human-robot interaction sensitivity under uniform speed or stationary conditions.

[0035] (2) Effectively eliminates high-frequency limit cycle oscillations. The introduction of the discrete state latching mechanism isolates the influence of low-speed nonlinear frictional mutations on the momentum observer from the signal source, eliminates high-frequency electromagnetic noise and mechanical micro-vibrations when the collaborative robotic arm is stationary or hovering with a load, and significantly improves the steady-state performance of the control system.

[0036] (3) Highly smooth interactive torque response. Soft dead zone mapping completely eliminates the step transition of torque commands, making the transition of the robot's underlying torque output continuous and smooth. While improving the operator's drag teaching or physical interaction experience, it effectively reduces the transient stress impact applied to the core mechanical transmission components and extends the service life of the machine. Attached Figure Description

[0037] Figure 1 This is a flowchart of the robot compliant control method in an embodiment of the present invention.

[0038] Figure 2 This is a flowchart illustrating the method for determining the effective external torque in an embodiment of the present invention.

[0039] Figure 3 This is a flowchart of the method for determining the effective reference torque in an embodiment of the present invention. Detailed Implementation

[0040] To gain a more detailed understanding of the features and technical content of the embodiments of the present invention, the implementation of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit the embodiments of the present invention.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing embodiments of the invention only and is not intended to limit the invention.

[0042] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0043] like Figure 1 As shown, the robot compliance control method in this embodiment of the invention includes the following steps:

[0044] S1. Obtain the desired joint position, desired joint velocity, desired joint acceleration, and effective external torque.

[0045] As an example, the expected joint position, expected joint velocity, and expected joint acceleration (which belong to feedforward acceleration) are the kinematic instructions issued by the trajectory planner to the underlying actuator.

[0046] As an example, an intelligent dynamic compliant dead-zone middleware is set up between the momentum observer (MOB) and the admittance / impedance controller. By using the intelligent dynamic compliant dead-zone middleware to determine the effective external torque, the true external contact force can be accurately isolated, and a smooth, high-frequency interference-free filtered effective external torque is output to the admittance / impedance controller, effectively solving the crosstalk problem of observation interference.

[0047] In some embodiments, the method for determining the effective external torque includes the following steps:

[0048] S11. Obtain the expected acceleration of the joint, the actual equivalent moment of inertia of the joint, the original observed external torque, and the actual velocity of the joint.

[0049] As an example, the intelligent dynamic compliant dead zone middleware obtains the expected acceleration of the joint from the trajectory planner, the original observed external torque and the actual velocity of the joint from the momentum observer, and the actual equivalent rotational inertia of the joint from the robot joint physical system.

[0050] The momentum observer uses the collected actual joint position, actual joint velocity, and motor feedback electromagnetic torque to calculate the original observed external torque.

[0051] In some embodiments, the momentum observer utilizes the formula: The original observed external torque for the current period is calculated. .in, This represents the preset momentum observer gain constant. This represents the preset equivalent nominal moment of inertia. This indicates the actual speed of the joint in the current cycle. This represents the actual velocity of the joint at the initial moment. This represents the feedback electromagnetic torque of the motor in the i-th cycle. This represents the original observed external torque during the (i-1)th period. This represents the friction torque compensation in the i-th cycle. This represents the gravitational torque compensation in the i-th cycle. Indicates the system control cycle. This represents the actual joint velocity in the i-th cycle. according to Calculations show that This represents the actual position of the joint in the i-th cycle. according to Calculated. As an example. =0, (That is, the initial observed external torque is equal to 0), according to calculate The method belongs to existing technology, according to calculate The method described is existing technology.

[0052] S12. Calculate the inertia error compensation coefficient based on the preset safety gain coefficient and the actual equivalent rotational inertia of the joint.

[0053] In some embodiments, the formula is used: The inertia error compensation coefficient for the current cycle is calculated. Where k represents the preset safety gain coefficient, , This represents the maximum absolute error limit for the current period. It ensures that the dynamically expanding dead zone completely encompasses the maximum spurious disturbance torque caused by inertia deviation. As an example, k=1.2.

[0054] In some embodiments, based on the actual equivalent moment of inertia of the joint in the current cycle, a preset maximum absolute error limit table is consulted to obtain... The preset maximum absolute error limit table is a table showing the correspondence between the actual equivalent moment of inertia of the joint obtained through calibration and the maximum absolute error limit. The maximum absolute error limit refers to the maximum value of the error between the actual equivalent moment of inertia of the joint and the nominal equivalent moment of inertia.

[0055] S13. Calculate the dynamic dead zone threshold based on the preset static dead zone threshold, joint expected acceleration, and inertia error compensation coefficient.

[0056] In some embodiments, the formula is used: The dynamic dead zone threshold for the current cycle is calculated. ;in, This represents the preset static dead zone threshold. This represents the expected acceleration of the joint in the current cycle.

[0057] S14. Determine the effective reference torque based on the actual joint speed, the preset speed threshold, the original observed external torque, and the preset friction noise tolerance band.

[0058] like Figure 3 As shown, in some embodiments, the method for determining the effective reference torque includes the following steps:

[0059] S141: Determine whether the joint is at extremely low speed or stationary under load. If so, execute S142; otherwise, execute S143.

[0060] In some embodiments, if This indicates that the joint is at extremely low speed or in a loaded, stationary state. This indicates the actual speed of the joint in the current cycle. This indicates the preset speed threshold.

[0061] S142. Based on the original observed external torque of the current cycle, the latched external torque of the previous cycle, and the preset friction noise tolerance band, determine the latched external torque of the current cycle, and then execute S145.

[0062] In some embodiments, the formula is used:

[0063] The latching external torque for the current cycle is calculated. .in, This indicates the latching external torque of the previous cycle. This indicates the preset friction noise tolerance band.

[0064] When this occurs, it indicates that a real and significant change has taken place in the external force, at which point... This indicates that the freeze has been lifted and the latch status has been updated. When this occurs, it indicates a small fluctuation in external force, which is a disturbance caused by a sudden change in Stribeck friction force. This indicates that the current latch state will be maintained.

[0065] When the joint is at extremely low speed or in a loaded static state, the system's determination mechanism enters a high-incidence zone of static / dynamic friction nonlinear transition. At this time, a dual-layer state determination is activated: only when... When the signal is valid, the system determines it to be a valid external intervention; otherwise, the system performs state latching to maintain a constant output. This logic effectively cuts off the servo system resonant closed loop induced by low-speed frictional abrupt changes by introducing time-domain hysteresis characteristics.

[0066] S143. Determine if the joint is in a normal high-speed movement state. If yes, execute S144; otherwise, end.

[0067] In some embodiments, if This indicates that the joint is in a normal high-speed movement state.

[0068] S144. Use the original observed external torque of the current cycle as the latched external torque of the current cycle, and then execute S145.

[0069] When the joint is in a normal high-speed movement state, This indicates that the latch is released and the latch status is updated in real time.

[0070] S145. Use the latched external torque of the current cycle as the effective reference torque for the current cycle, and then end. , This represents the effective reference torque for the current cycle.

[0071] S15. Based on the effective reference torque and dynamic dead zone threshold, the effective external torque is calculated.

[0072] In some embodiments, the formula is used:

[0073] The effective external torque of the current period is calculated. ;in, Represents a symbolic function. When... hour, ;when hour, ;when hour, .

[0074] S2. Based on the desired joint position, desired joint velocity, desired joint acceleration, effective external torque, and preset target impedance parameters, calculate and generate position / torque correction commands for the robot's compliant interactive actions.

[0075] As an example, the preset target impedance parameters include target inertia, target damping, and target stiffness parameters. Step S2 is executed by the admittance / impedance controller. The admittance / impedance controller calculates and generates position / torque correction commands for the robot's compliant interaction actions based on the target's second-order impedance dynamic equation; this calculation and generation method is existing technology.

[0076] S3. Execute low-level joint servo control and torque output based on the position / torque correction instructions of the robot's compliant interactive actions.

[0077] As an example, step S3 is performed by the robot's underlying joint servo driver.

[0078] To further illustrate the specific control mechanism of the embodiments of the present invention, a discrete control system (control period is...) is used as an example. Taking a robot as an example, this paper illustrates the algorithm response logic when the robot is in three typical physical conditions:

[0079] Operating Condition 1: Rapid Acceleration and Deceleration Tracking Condition (Corresponds to the solution of spurious disturbance problem caused by inertia matching)

[0080] Scenario Description: The robot is currently performing a high-acceleration trajectory tracking task without external physical intervention. At this moment, the trajectory planner issues the desired acceleration for each joint. The absolute value is in the peak range.

[0081] Execution logic: Real-time reading , and through equation Calculate the dynamic dead zone threshold for the current period. Due to modeling errors between the physical inertia and the nominal inertia of actual mechanical systems, the momentum observer, affected by inertial coupling, will output a spurious external torque observation value caused by inertia mismatch. At this point, the dynamic dead zone threshold... Desired acceleration of joint Synchronous broadening, the broadened range of which constitutes an effective mathematical envelope, ensures It always holds true.

[0082] Effect: Dead zone mapping output The admittance / impedance controller is effectively isolated from false observation signals, ensuring that the robot can stably track the target trajectory in a highly rigid state and completely avoid non-command pose jitter caused by rapid acceleration and deceleration.

[0083] Operating Condition 2: Loaded low-speed or stationary parking conditions (addressing issues related to sudden changes in low-speed friction and limit cycles)

[0084] Scenario Description: The robot is either stationary, hovering, or performing extremely low-speed motion while carrying an external load. This is due to the nonlinear conversion characteristics of static and dynamic friction within the mechanical reducer (which occurs...). (Region), the momentum observer will output a raw signal containing high-frequency micro-amplitude fluctuations even when no external force is applied. .

[0085] Execution logic: The system monitors and confirms the absolute value of the actual joint velocity in the current cycle. speed less than the preset threshold (Right now Immediately trigger the state latch subroutine; calculate the absolute value of the deviation between the original observed external torque of the current cycle and the latched external torque of the previous cycle. Given that this fluctuation originates solely from internal frictional abrupt changes, the absolute value of the deviation... Determined to be less than or equal to the preset frictional noise tolerance band. Force state freeze and update variables. .

[0086] Effect: The effective external torque input to the admittance / impedance controller remains absolutely constant, effectively blocking the high-frequency oscillation adjustment of the system control quantity caused by the slight frictional jitter, and completely eliminating the limit loop phenomenon of the servo system and the high-frequency electromagnetic noise of the motor.

[0087] Working Condition 3: Real-world physical human-machine interaction working condition (corresponding to the solution of torque step and mechanical shock problems)

[0088] Scenario Description: The operator applies a dragging force to the robotic arm, or the robotic arm unexpectedly experiences an external physical collision. The actual external contact force compels the effective reference torque of the current cycle. A significant increase, exceeding the dynamic dead zone threshold of the current cycle. .

[0089] Execution logic: If true, the soft dead zone mapping equation is triggered, the execution of zero-bit output stops, and the operation is converted to continuous mapping algebra operations: .

[0090] Effect: In the transient state where the external torque exceeds the dynamic dead zone threshold, the effective external torque output to the admittance / impedance controller is determined. It avoids amplitude step jumps equal to the dynamic dead zone threshold, and it rigorously... The coordinate point starts and rises steadily and continuously, ensuring a highly smooth yielding behavior. While optimizing the human-computer interaction feel, it significantly reduces the impact damage of instantaneous step torque on core mechanical transmission components.

[0091] In addition, embodiments of the present invention also provide a robot compliance control system, including a memory and a processor. The memory stores a computer program, and the processor is configured to execute the computer program to implement the above-described robot compliance control method.

[0092] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention 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 the present invention should be included within the scope of protection of the present invention.

Claims

1. A robot compliant control method, comprising: Obtain the desired joint position, desired joint velocity, desired joint acceleration, and effective external torque; Based on the desired joint position, desired joint velocity, desired joint acceleration, effective external torque, and preset target impedance parameters, position / torque correction commands for the robot's compliant interactive actions are calculated and generated. Based on the position / torque correction command, perform underlying joint servo control and torque output; The method for determining the effective external torque is characterized by comprising: Obtain the expected acceleration of the joint, the actual equivalent moment of inertia of the joint, the original observed external torque, and the actual velocity of the joint; Based on the preset safety gain coefficient and the actual equivalent rotational inertia of the joint, the inertia error compensation coefficient is calculated. The dynamic dead zone threshold is calculated based on the preset static dead zone threshold, joint expected acceleration, and inertia error compensation coefficient. The effective reference torque is determined based on the actual joint speed, the preset speed threshold, the original observed external torque, and the preset friction noise tolerance band. The effective external torque is calculated based on the effective reference torque and the dynamic dead zone threshold.

2. The robot compliant control method according to claim 1, characterized in that, The method for determining the effective reference torque includes: When the joint is at extremely low speed or stationary under load, the latching external torque for the current cycle is determined based on the original observed external torque of the current cycle, the latching external torque of the previous cycle, and the preset friction noise tolerance band. When the joint is in a normal high-speed motion state, the original observed external torque of the current cycle is used as the latched external torque of the current cycle; The latching external torque of the current cycle is used as the effective reference torque of the current cycle.

3. The robot compliant control method according to claim 2, characterized in that: like This indicates that the joint is at extremely low speed or in a loaded, stationary state; if This indicates that the joint is in a normal, high-speed movement state; among which, This indicates the actual speed of the joint in the current cycle. This indicates the preset speed threshold.

4. The robot compliant control method according to claim 2, characterized in that, When the joint is at extremely low speed or stationary under load, the following formula is used: The latching external torque for the current cycle is calculated. ;in, This represents the original observed external torque for the current period. This indicates the latching external torque of the previous cycle. This indicates the preset friction noise tolerance band.

5. The robot compliant control method according to claim 1, characterized in that, Using the formula: The inertia error compensation coefficient for the current cycle is calculated. Where k represents the preset safety gain coefficient, , This indicates the maximum absolute error limit for the current period.

6. The robot compliant control method according to claim 5, characterized in that: Based on the actual equivalent moment of inertia of the joint in the current cycle, the preset maximum absolute error limit table is consulted to obtain the... The preset maximum absolute error limit table is a table showing the correspondence between the actual equivalent rotational inertia of the joint and the maximum absolute error limit obtained through calibration.

7. The robot compliant control method according to claim 1, characterized in that, Using the formula: The dynamic dead zone threshold for the current cycle is calculated. ;in, This represents the preset static dead zone threshold. This represents the inertia error compensation coefficient for the current cycle. This represents the expected acceleration of the joint in the current cycle.

8. The robot compliant control method according to claim 1, characterized in that: Using the formula: The effective external torque of the current period is calculated. ;in, This represents the dynamic dead zone threshold for the current period. This represents the effective reference torque for the current cycle. Represents a symbolic function.

9. The robot compliant control method according to any one of claims 1 to 8, characterized in that, The method for determining the original observed external torque includes: Obtain the actual joint position, actual joint velocity, and electromagnetic torque fed back by the motor; Using the formula: The original observed external torque for the current period is calculated. ;in, This represents the preset momentum observer gain constant. This represents the preset equivalent nominal moment of inertia. This indicates the actual speed of the joint in the current cycle. This represents the actual velocity of the joint at the initial moment. This represents the feedback electromagnetic torque of the motor in the i-th cycle. This represents the original observed external torque during the (i-1)th period. This represents the friction torque compensation in the i-th cycle. This represents the gravitational torque compensation in the i-th cycle. Indicates the system control cycle. This represents the actual joint velocity in the i-th cycle. according to Calculations show that This represents the actual position of the joint in the i-th cycle. according to Calculated.

10. A robot compliance control system, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: The processor is configured to execute the computer program to implement the robot compliant control method as described in any one of claims 1 to 9.

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