Spherical joint module vibration suppression sliding mode control method based on acceleration feedback

Abstract

The invention provides a spherical joint module vibration suppression sliding mode control method based on acceleration feedback, and the method employs an accelerometer to measure the acceleration information of a spherical joint module during trajectory tracking, and feeds the acceleration information back to a sliding mode controller, thereby constructing a novel sliding mode controller. According to the controller, the trajectory tracking performance of the ball joint module is effectively improved, so that the trajectory of the ball joint module can track an expected trajectory within limited time, and the steady-state error of trajectory tracking of the ball joint module is reduced; meanwhile, the acceleration feedback sliding mode controller can effectively reduce the chattering phenomenon in the trajectory tracking process of the ball joint module, closed-loop acceleration feedback enables the ball joint module to achieve real-time vibration suppression under the condition of sudden external interference, and the robust performance of the control system is improved.

Description

Technical Field

[0001] This invention belongs to the field of ball joint control, specifically relating to a sliding mode control method for vibration suppression of a spherical joint module based on acceleration feedback. Background Technology

[0002] With the deep integration of artificial intelligence and mechanical engineering, humanoid robots are gradually becoming a core force driving the transformation of intelligent manufacturing and smart living. Faced with the increasing complexity of human-robot collaboration scenarios, achieving high-precision tracking performance and dynamic stability of key drive components for robot motion has become a core issue in the current robotics field. In the actuator design of industrial and intelligent robots, solutions for achieving multi-degree-of-freedom motion typically rely on multiple single-degree-of-freedom motors and complex transmission mechanisms, leading to structural redundancy, insufficient flexibility, and difficulties in high-precision motion control. To address these issues, a novel, highly integrated multi-degree-of-freedom ball joint module has been proposed, offering advantages such as simple structure, high integration, and high motion accuracy.

[0003] Multi-degree-of-freedom ball joint modules are a new type of actuator designed to achieve high-precision three-dimensional motion in space. Due to the presence of components such as reducers in the joint assembly, the joint portion has a flexible structure, causing vibrations during movement, especially during start-up and stop phases. In practical use, this affects operational accuracy and positioning time. Currently, three common vibration suppression methods are used for multi-degree-of-freedom ball joint modules: First, by adding damping materials, optimizing the mechanical structure design, and using vibration isolators, the system's inherent structural characteristics or passive components are utilized to suppress vibration. Second, by preprocessing the motion trajectory of the multi-degree-of-freedom ball joint module to avoid abrupt changes in position, velocity, and acceleration, vibration excitation is prevented, thus achieving vibration suppression. Third, by using external energy input and dynamically changing energy values, certain parameters in the system are adjusted to suppress the vibration of the ball joint module. However, the above vibration suppression methods have the following drawbacks: First, they rely on the structural characteristics of the system itself or the addition of passive components to suppress vibration by increasing damping materials, optimizing mechanical structure design, and using vibration isolators. Second, they rely on preprocessing the motion trajectory of the multi-degree-of-freedom ball joint module to avoid abrupt changes in the position, velocity, and acceleration of the ball joint actuator, thereby preventing the excitation of vibration and achieving vibration suppression. Third, they rely on methods such as external energy input and dynamic change of energy values ​​to suppress the vibration of the ball joint module by adjusting certain parameters in the system.

[0004] However, the existing technology has the following disadvantages:

[0005] (1) The method of utilizing the structural characteristics of the system itself or adding passive components has the problems of poor flexibility and insignificant effect on low-frequency vibration suppression;

[0006] (2) The trajectory preprocessing is designed only for the "ideal motion scenario". When the multi-degree-of-freedom ball joint module encounters sudden external interference, there is no real-time feedback mechanism to correct the trajectory deviation. The interference energy may be amplified by the "rigid constraints" of the trajectory planning (such as forced tracking of the original trajectory leading to impact vibration).

[0007] (3) Methods such as external energy input and dynamic change of energy value rely on accurate system model and disturbance prediction. If the actual vibration characteristics deviate greatly from the model, parameter adjustment may not achieve the best effect, or even cause resonance. Summary of the Invention

[0008] This invention provides a sliding mode control method for vibration suppression of a ball joint module based on acceleration feedback. The aim is to reduce the steady-state error of the ball joint module's trajectory tracking within a finite time, thereby achieving good trajectory tracking performance. Simultaneously, by real-time acquisition and feedback of the acceleration information of the output shaft at the end of the ball joint module, vibration suppression of the ball joint module is achieved in real-time and efficiently. The specific technical solution is as follows:

[0009] A sliding mode control method for vibration suppression of a spherical joint module based on acceleration feedback includes the following steps:

[0010] S1: By installing a triaxial accelerometer on the output shaft at the end of the ball joint module, the acceleration in the X, Y, and Z directions during the movement of the ball joint module is obtained. ;

[0011] S2: Design a sliding surface for sliding mode control based on acceleration feedback;

[0012] S3: Design a sliding mode controller based on acceleration feedback.

[0013] The present invention has the following beneficial effects:

[0014] This invention employs an accelerometer to measure the acceleration information of a ball joint module during trajectory tracking and feeds this acceleration information back to a sliding mode controller, thereby constructing a novel sliding mode controller. This controller not only effectively improves the trajectory tracking performance of the ball joint module, enabling it to track the desired trajectory within a finite time and reducing the steady-state error of the trajectory tracking, but also effectively reduces chattering during the trajectory tracking process. The closed-loop acceleration feedback allows the ball joint module to achieve real-time vibration suppression even under sudden external disturbances, improving the robustness of the control system.

[0015] This invention effectively improves the trajectory tracking performance of ball joint modules, enabling the ball joint module to track the desired trajectory within a finite time, reducing the steady-state error of the ball joint module's trajectory tracking. At the same time, the acceleration feedback sliding mode controller can effectively reduce the chattering phenomenon during the trajectory tracking process of the ball joint module. The closed-loop acceleration feedback enables the ball joint module to achieve real-time vibration suppression even under sudden external interference, improving the robustness of the control system. Attached Figure Description

[0016] Figure 1 This is a control block diagram for sliding mode control based on acceleration feedback;

[0017] Figure 2 A comparison chart of the X-axis position tracking curves for the three control methods;

[0018] Figure 3 A comparison chart of the Y-axis position tracking curves for the three control methods;

[0019] Figure 4 A comparison chart of Z-axis position tracking curves for three control methods;

[0020] Figure 5 The position error curve for PD control;

[0021] Figure 6 The position error curve is a traditional acceleration feedback curve.

[0022] Figure 7 The position curve for sliding mode control based on acceleration feedback;

[0023] Figure 8 A comparison chart of X-axis acceleration for the three control methods;

[0024] Figure 9 A comparison chart of Y-axis acceleration for three control methods;

[0025] Figure 10 This is a comparison chart of Z-axis acceleration for three control methods. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other. To achieve the above objectives, this invention adopts the following technical solution.

[0027] like Figure 1As shown, this invention provides a sliding mode control method for vibration suppression of a spherical joint module based on acceleration feedback, comprising the following steps:

[0028] S1: By installing a triaxial accelerometer on the output shaft at the end of the ball joint module, the acceleration in the X, Y, and Z directions during the movement of the ball joint module is obtained. ;

[0029] S2: The steps for designing a sliding surface based on acceleration feedback sliding mode control are as follows:

[0030] To enable rapid convergence of tracking errors and maintain high tracking accuracy, the sliding surface is designed as follows:

[0031] ;

[0032] In the formula, , , which are the position error vector and velocity error vector of the ball joint module motor side, respectively; These represent the given position vector and the actual position vector on the motor side of the ball joint module, respectively. These represent the given position signals of the motor in the X, Y, and Z axes of the ball joint module, respectively. These represent the actual position signals of the motors in the X, Y, and Z axes of the ball joint module, respectively. These represent the given velocity vector and the actual velocity vector on the motor side of the ball joint module, respectively. These represent the given speed signals of the motor in the X, Y, and Z axes of the ball joint module, respectively. These represent the actual speed signals of the motor in the X, Y, and Z axes of the ball joint module, respectively. It is the sliding surface design parameter matrix.

[0033] S3: Design a sliding mode controller based on acceleration feedback as follows:

[0034] ;

[0035] in, Here is the rotational inertia matrix of the ball joint module. and It is the sliding mode gain parameter matrix. It is the acceleration gain matrix. For sliding mode switching, This represents the angular acceleration vector at the end of the output shaft of a given ball joint module. This represents the actual angular acceleration vector at the end of the output shaft of the ball joint module. These represent the given angular accelerations at the end of the ball joint module's output shaft in the X, Y, and Z axes, respectively. These represent the actual angular accelerations of the ball joint module's output shaft end in the X, Y, and Z axes, respectively. This refers to the control torque on the motor side of the ball joint module.

[0036] This is also the input signal from the ball joint module to the motor side; the output ratio of the ball joint motor is... The motor-side output angle is obtained after receiving the input signal to the motor. This feedback is then fed back to the vibration suppression sliding mode controller based on acceleration feedback. Simultaneously, the input torque vector on the connecting rod side of the ball joint module is calculated. .

[0037] Input torque vector on the link side of the ball joint module The calculation formula is as follows:

[0038] ;

[0039] in, This is the joint stiffness matrix of the ball joint module. This is the gear ratio matrix for the ball joint module's reducer. This represents the actual position vector of the output shaft end of the ball joint module.

[0040] To verify the effectiveness and superiority of the vibration suppression sliding mode control strategy based on acceleration feedback designed in this invention in trajectory tracking and vibration suppression control of ball joint modules, the derived dynamic model of a ball joint module with flexible joints is used as the controlled object, and the desired trajectory of the connecting rod side is given as follows:

[0041] ;

[0042] The initial state of the ball joint is: , .

[0043] Figure 2 , Figure 3 and Figure 4 These represent ordinary proportional-derivative control. Traditional acceleration feedback control is adopted. The vibration suppression sliding mode control strategy based on acceleration feedback of this invention Trajectory tracking path under the desired trajectory on the X, Y, and Z axes. Figure 5 , Figure 6 , Figure 7 The demonstrations showcased three controllers—PD, PDAFC, and SMAFC—in tracking the desired trajectory. , , The tracking error curves are shown in these six figures. From these figures, it can be inferred that the SMAFC proposed in this invention significantly outperforms PD and PDAFC in trajectory tracking performance. Figure 5 , Figure 6 , Figure 7 A comparison of the three graphs clearly shows that the SMAFC has the smallest trajectory tracking error among the three controllers. Figure 8 , Figure 9 , Figure 10 The demonstrations showcased three controllers—PD, PDAFC, and SMAFC—in tracking the desired trajectory. , , The acceleration curves on the X, Y, and Z axes are used to show the vibration of the three controllers when tracking the trajectory. A comparison of these three graphs shows that the SMAFC proposed in this invention effectively reduces the acceleration fluctuation of the ball joint module during trajectory tracking and suppresses the chattering phenomenon of the ball joint actuator.

Claims

1. A sliding mode control method for vibration suppression of a spherical joint module based on acceleration feedback, characterized in that, Includes the following steps: S1: By installing a triaxial accelerometer on the output shaft at the end of the ball joint module, the acceleration in the X, Y, and Z directions during the movement of the ball joint module is obtained. ; S2: Design a sliding mode controller based on acceleration feedback.

2. The sliding mode control method for vibration suppression of a spherical joint module based on acceleration feedback according to claim 1, characterized in that, In step S3, the sliding mode controller based on acceleration feedback is as follows: ； in, Here is the rotational inertia matrix of the ball joint module. and It is the sliding mode gain parameter matrix. It is the acceleration gain matrix. For sliding mode switching, This represents the angular acceleration vector at the end of the output shaft of a given ball joint module. This represents the actual angular acceleration vector at the end of the output shaft of the ball joint module, where These represent the given angular accelerations at the end of the ball joint module's output shaft in the X, Y, and Z axes, respectively. These represent the actual angular accelerations of the ball joint module's output shaft end in the X, Y, and Z axes, respectively. For the control torque on the motor side of the ball joint module; In sliding mode controllers based on acceleration feedback The expression is as follows: ； In the formula, , , which are the position error vector and velocity error vector of the ball joint module motor side, respectively; These represent the given position vector and the actual position vector on the motor side of the ball joint module, respectively. These represent the given position signals of the motor in the X, Y, and Z axes of the ball joint module, respectively. These represent the actual position signals of the motors in the X, Y, and Z axes of the ball joint module, respectively. These represent the given velocity vector and the actual velocity vector on the motor side of the ball joint module, respectively. These represent the given speed signals of the motor in the X, Y, and Z axes of the ball joint module, respectively. These represent the actual speed signals of the motor in the X, Y, and Z axes of the ball joint module, respectively. It is the sliding surface design parameter matrix; Sliding mode switching item The calculation method is as follows: 。 3. The sliding mode control method for vibration suppression of a spherical joint module based on acceleration feedback according to claim 2, characterized in that, This is the input signal from the ball joint module to the motor side; the output ratio of the ball joint motor is... The motor-side output angle is obtained after receiving the input signal to the motor. This feedback is then fed back to the vibration suppression sliding mode controller based on acceleration feedback, and the input torque vector on the connecting rod side of the ball joint module is calculated simultaneously. .

4. The sliding mode control method for vibration suppression of a spherical joint module based on acceleration feedback according to claim 3, characterized in that, Input torque vector on the link side of the ball joint module The calculation formula is as follows: ； in, This is the joint stiffness matrix of the ball joint module. This is the gear ratio matrix for the ball joint module's reducer. This represents the actual position vector of the output shaft end of the ball joint module.

5. The sliding mode control method for vibration suppression of a spherical joint module based on acceleration feedback according to claim 1, characterized in that, In step S1, acceleration is obtained by a triaxial accelerometer installed on the output shaft at the end of the ball joint module.

6. A sliding mode control device for vibration suppression of a spherical joint module based on acceleration feedback, characterized in that, include: The acceleration acquisition module acquires the acceleration in the X, Y, and Z directions during the movement of the ball joint module by installing a triaxial accelerometer on the output shaft at the end of the ball joint module. ; Sliding mode controller: Design of a sliding mode controller based on acceleration feedback.

7. An electronic device, characterized in that, include: One or more processors; A memory for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method of any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, It stores executable instructions that, when executed by a processor, cause the processor to perform the method described in any one of claims 1 to 5.

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