CN-121618903-B - Control method for effectively inhibiting position response overshoot slip mode of series elastic actuator

CN121618903BCN 121618903 BCN121618903 BCN 121618903BCN-121618903-B

Abstract

The invention discloses a control method for effectively inhibiting position response overshoot slip mode of a series elastic actuator. The method comprises the steps of designing a sliding mode controller and a total disturbance decoupling observer based on a dynamic model of a series elastic actuator system in consideration of lumped disturbance, wherein the sliding mode controller comprises a Gaussian dynamic gain sliding mode surface and an anti-integral saturation supercoiled approach law, inputting a state feedback vector of the series elastic actuator system into the lumped disturbance decoupling observer, outputting lumped disturbance torque of a motor side and a load side of the series elastic actuator system after processing, inputting the lumped disturbance torque into the sliding mode controller together with a preset position instruction of the load side, outputting a q-axis current reference value after processing, and further performing closed-loop control on the position of the load side of the series elastic actuator system. In the method, in the point-to-point position control of the load side position of the series elastic actuator, overshoot of the load side position response can be effectively reduced while the high dynamic response capability of the system is maintained.

Inventors

CAO YANFEI
ZHANG CHENDONG
SHI TINGNA
XIA CHANGLIANG

Assignees

浙江大学
浙江大学先进电气装备创新中心

Dates

Publication Date: 20260505
Application Date: 20260202

Claims (9)

1. The method for controlling the position response overshoot slip mode of the series elastic actuator is characterized by comprising the following steps of: Step 1) designing a Gaussian dynamic gain sliding mode position controller and a lumped disturbance decoupling observer based on a dynamic model of a series elastic actuator system in consideration of lumped disturbance, wherein the Gaussian dynamic gain sliding mode position controller comprises a Gaussian dynamic gain sliding mode surface and an anti-integral saturation supercoiled approach law; Step 2) inputting a state feedback vector of the series elastic actuator system into a lumped disturbance decoupling observer, outputting lumped disturbance torques of a motor side and a load side of the series elastic actuator system after processing, then inputting the lumped disturbance torques and a preset position instruction of the load side into a Gaussian dynamic gain sliding mode position controller together, and outputting a q-axis current reference value after processing; Step 3) performing closed-loop control on the load side position of the series elastic actuator system according to the q-axis current reference value to realize sliding mode control for inhibiting position response overshoot; in the step 1), the gaussian dynamic gain sliding mode surface s is specifically as follows: ; ; ; Wherein c 1 、c 2 、c 3 and c 4 represent the first, second, third and fourth sliding mode surface coefficients of the gaussian dynamic gain sliding mode surface s, respectively, h () and g () represent the first and second anti-overshoot dynamic gains, respectively, x 1 、x 2 、x 3 and x 4 represent the position difference, rotation speed difference, acceleration difference and jerk difference of the load side, respectively, and m and n represent the first and second anti-overshoot coefficients, respectively.
2. The method for effectively suppressing the overshoot slip mode of the position response of the series elastic actuator according to claim 1, wherein in the step 1), the series elastic actuator system comprises a motor, a harmonic reducer, an elastic torsion spring and a load, and the Gaussian dynamic gain slip mode position controller is specifically as follows: ; Wherein i q-ref represents a q-axis current reference value, N represents a gear ratio of the harmonic reducer, J M and J L represent rotational inertia of the motor side and the load side, respectively, K t represents a torque coefficient of the motor side, K s represents a nominal value of stiffness of the elastic torsion spring, f d represents a dynamics model-related component, and f s represents a gaussian dynamic gain slip plane design component; representing the anti-integral saturated supercoiled approach law design component.
3. The method for effectively suppressing the position response overshoot slip mode of the tandem elastic actuator according to claim 2, wherein the dynamics model-related component f d is specifically as follows: ; Wherein, the Preset position command representing load side Θ M and θ L represent the positions of the motor side and the load side, respectively, and T M-lump and T L-lump represent the lumped disturbance torques of the motor side and the load side, respectively; Representing the second derivative of the lumped disturbance torque on the load side.
4. The method for effectively suppressing the position response overshoot slip mode of the series elastic actuator according to claim 2, wherein the Gaussian dynamic gain slip mode surface design component f s is specifically as follows: 。
5. The method for effectively suppressing an overshoot slip-mode control of a series elastic actuator position response of claim 4, wherein said anti-integral saturation supercoiled approach law design component The method comprises the following steps: ; ; ; Wherein r ori and r sat respectively represent the opposite number of the approach law and the saturation value thereof; And S represents a Gaussian dynamic gain sliding mode surface; and I sat represents the q-axis saturation current at the motor side.
6. The method for effectively suppressing an overshoot slip-mode control of a series elastic actuator position response of claim 5, wherein in said step 1), an anti-integral saturation supercoiled approach law is provided The method comprises the following steps: 。
7. The method for effectively suppressing the position response overshoot slip mode of the series elastic actuator according to claim 1, wherein in the step 1), the lumped disturbance decoupling observer is as follows: ; Wherein s lump represents the sliding mode surface vector of the lumped disturbance decoupling observer, ω represents the rotation speed measurement value vector, And Representing the rotation speed observation vector and its first derivative, e and e, respectively The method comprises the steps of respectively representing error vectors and first derivatives thereof between a rotation speed measured value vector and a rotation speed observed value vector, wherein J represents a moment of inertia matrix, K represents an input gain matrix; Representing a state feedback vector, u= [ i q , θ M /N-θ L ] T ,i q ] represents a q-axis current measurement value on the motor side, θ M and θ L represent positions on the motor side and the load side, respectively, and N represents a gear ratio of the harmonic reducer; And Representing the lumped disturbance observer vector and the first derivative thereof, =[ , Each of the values " T ,T M-lump " and "T L-lump " represents the lumped disturbance torque on the motor side and the load side, k represents the lumped disturbance switching gain matrix, p represents the switching vector, and g represents the lumped disturbance feedback gain matrix.
8. An electronic device comprising a memory and a processor coupled to each other, wherein the memory stores program data and the processor invokes the program data to perform the method of any of claims 1-7.
9. A computer readable storage medium having stored thereon program data, which when executed by a processor implements the method of any of claims 1-7.

Description

Control method for effectively inhibiting position response overshoot slip mode of series elastic actuator Technical Field The invention relates to an actuator sliding mode control method, relates to the technical field of robot joint motor control, and in particular relates to a method for effectively inhibiting the position response overshoot sliding mode of a series elastic actuator. Background The series elastic actuator consists of a motor, a high-transmission-ratio speed reducer and an elastic torsion spring, has the advantages of high-precision transmission, high safety and the like, is a key execution unit in the robot, and is a hot spot for the research of the robot industry for accurate and effective control. Because of the existence of the elastic torsion spring, the series elastic actuator is more sensitive to external interference than the rigid actuator, and the difficulty in controlling the position of the series elastic actuator is increased. The sliding mode variable structure control is used as a high-robustness algorithm with low model dependence and strong anti-interference capability, and more students use the sliding mode variable structure control in the position control of the series elastic actuator. The sliding mode position controller proposed by a scholars combines the integral approach law and the quasi-continuous sliding mode control signal into a new approach law, and compared with the constant-speed approach law, the sliding mode position controller realizes higher position control bandwidth and smaller buffeting. The learner adopts the thought of 0-order sliding mode, designs a terminal sliding mode surface containing control quantity, avoids the problem of terminal sliding mode singularity, optimizes the selection of state variables, and enables the controller to realize the position control without steady-state errors under the condition of loading. At present, research on sliding mode position control of a series elastic actuator is focused on steady-state precision and buffeting reduction, and research on overshoot reduction in transient process is lacking. In some scenarios in point-to-point control conditions, overshoot of the position response is not allowable, so it is interesting to study how to suppress the position response overshoot in the sliding mode position control of a series elastic actuator. It has been found that due to the existence of the elastic torsion spring, the dynamic order of the system increases, and in order to design the sliding mode position controller, a high-order differential term, namely an acceleration error term and a jerk error term, needs to be added in the sliding mode surface, and acceleration current provided by the terms in the deceleration stage can cause overshoot of the position response. The constant sliding mode surface applied in the current research cannot effectively weaken or inhibit the accelerating current, so that the problem of overshoot of the position response cannot be well solved. In addition, integration links in the approach law (e.g., supercoiled approach law) exacerbate this overshoot phenomenon. Disclosure of Invention In order to solve the problems in the background art, the invention provides a control method for effectively inhibiting the position response overshoot slip mode of a series elastic actuator. Aiming at the problem that the sliding mode position controller of the series elastic actuator cannot effectively inhibit overshoot, the invention introduces a Gaussian function into the design of a sliding mode surface, and designs a variable parameter sliding mode surface, namely a Gaussian dynamic gain sliding mode surface. The acceleration current provided by the acceleration error term and the jerk error term in the deceleration stage of the load positioning process is counteracted, and the overshoot of the position response is reduced. In addition, an integral link in the approach law is optimized, and an anti-integral saturated supercoiled approach law is designed to further inhibit overshoot of the position response. The technical scheme adopted by the invention is as follows: The invention relates to a method for effectively restraining the position response overshoot slip mode of a series elastic actuator, which comprises the following steps: Step 1) designing a Gaussian dynamic gain sliding mode position controller and a lumped disturbance decoupling observer based on a dynamic model considering lumped disturbance of a series elastic actuator system, wherein the dynamic model considers a reduction ratio, and the Gaussian dynamic gain sliding mode position controller comprises a Gaussian dynamic gain sliding mode surface and an anti-integral saturated supercoiled approach law. And 2) inputting the state feedback vector of the series elastic actuator system into a lumped disturbance decoupling observer, outputting lumped disturbance torques of a motor side and a load side of the series elastic ac