scholarly journals Time-Varying Integral Adaptive Sliding Mode Control for the Large Erecting System

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Xie Zheng ◽  
Xie Jian ◽  
Du Wenzheng ◽  
Li Liang ◽  
Guo Yang
Keyword(s):  
Sliding Mode Control ◽  
Control Strategy ◽  
Sliding Mode ◽  
Adaptive Sliding Mode Control ◽  
Time Varying ◽  
Tracking Accuracy ◽  
Mode Control ◽  
Global Robustness ◽  
System Uncertainties ◽  
Integral Sliding Surface

Considering the nonlinearities, uncertainties of large erecting system, and the circumstance disturbances in erecting process, a novel sliding mode control strategy is proposed in this research. The proposed control strategy establishes the sliding mode without reaching phase using an integral sliding surface. Thus, robustness against uncertainties increases from the very beginning of the process. Furthermore, adaptive laws are used for the controller to estimate the unknown but bounded system uncertainties. Therefore, the upper bounds of the system uncertainties are not required to be known in advance. Then, the time-varying term is applied to ensure the global robustness. Moreover, the boundary layer method is used to attenuate the high frequency chattering. The experiment results demonstrated that the proposed strategy could effectively restrain parametric uncertainties and external disturbances and improve the tracking accuracy in the erecting process. In addition, the control performance of the proposed control strategy is better than that of the PID control and the conventional sliding mode control.

PMLSM Nonlinear Integral Sliding Mode Control Based on Gain Time- Varying Reaching Law

2020 ◽  
Vol 13 (5) ◽  
pp. 743-750
Author(s):  
Chao Zhang ◽  
Liwei Zhang ◽  
Bo Peng ◽  
He Zhao
Keyword(s):  
Sliding Mode Control ◽  
Permanent Magnet ◽  
Sliding Mode ◽  
Dynamic Performance ◽  
Linear Motor ◽  
Time Varying ◽  
Sliding Surface ◽  
Reaching Law ◽  
Mode Control ◽  
Global Robustness

Background: The permanent magnet synchronous linear motor is a strongly coupled, nonlinear system. It has been applied in many fields, especially in the field of machining lathes and rail transportation. In order to ensure the permanent magnet synchronous linear motor has good dynamic performance and robustness, sliding mode control is gradually applied to the control system of permanent magnet synchronous linear motor. However, in the traditional sliding mode control, the convergence speed is slow, and the robust performance is poor when the sliding surface is not reached. Objective: The main purpose of this paper is to improve the dynamic performance and robustness of the permanent magnet synchronous linear motor during the process of approaching the sliding surface. Methods: Firstly, the type of nonlinear curve with "small error reduction, large error saturation" is introduced to design a nonlinear integral speed controller with global robustness. Secondly, the gain rate time-varying reaching law is introduced to reduce "chattering". Finally, using a symbolic tangent function instead of a sign function in designing a sliding mode observer reduces fluctuations in load observations. Results: Finally, the correctness and effectiveness of the control method are proved by simulation. Conclusion: The results of the simulation show that the nonlinear integral sliding mode controller based on gain time-varying reaching law is shown to have good global robustness and dynamic performance.

scholarly journals Fractional-order sliding mode control for a class of uncertain nonlinear systems based on LQR

2017 ◽  
Vol 14 (2) ◽  
pp. 172988141769429 ◽  
Author(s):  
Dong Zhang ◽  
Lin Cao ◽  
Shuo Tang
Keyword(s):  
Sliding Mode Control ◽  
Fractional Order ◽  
Control Strategy ◽  
Sliding Mode ◽  
Tracking Error ◽  
Uncertain Nonlinear Systems ◽  
Mode Control ◽  
Output System ◽  
System Uncertainties ◽  
Error Dynamics

This article presents a new fractional-order sliding mode control (FOSMC) strategy based on a linear-quadratic regulator (LQR) for a class of uncertain nonlinear systems. First, input/output feedback linearization is used to linearize the nonlinear system and decouple tracking error dynamics. Second, LQR is designed to ensure that the tracking error dynamics converges to the equilibrium point as soon as possible. Based on LQR, a novel fractional-order sliding surface is introduced. Subsequently, the FOSMC is designed to reject system uncertainties and reduce the magnitude of control chattering. Then, the global stability of the closed-loop control system is analytically proved using Lyapunov stability theory. Finally, a typical single-input single-output system and a typical multi-input multi-output system are simulated to illustrate the effectiveness and advantages of the proposed control strategy. The results of the simulation indicate that the proposed control strategy exhibits excellent performance and robustness with system uncertainties. Compared to conventional integer-order sliding mode control, the high-frequency chattering of the control input is drastically depressed.

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