Approach Angle-Based Saturation Function of Modified Complementary Sliding Mode Control for PMLSM

Hongyan Jin,Ximei Zhao

doi:10.1109/access.2019.2939140

Abstract

In this paper, an approach angle-based saturation function of modified complementary sliding mode control (MCMSC) method was proposed to overcome the influence of uncertainties such as parameter variations and external disturbances on permanent magnet linear synchronous motor (PMLSM) servo system. On the foundation of the mathematical model considering uncertainties of PMLSM and the theory of sliding mode control (SMC), complementary sliding mode control (CSMC) method was designed by combining the integral sliding surface with the complementary sliding surface. By using the continuous saturation function, CSMC can efficiently eliminate the system chattering phenomenon caused by the discontinuous function in SMC and further improve the position tracking accuracy. However, the saturation function makes the boundary layer in CSMC constant, so the asymptotic stability of the system cannot be guaranteed. Hence, an approach angle-based saturation function of MCSMC was designed to realize the dynamic change of the boundary layer, which can diminish the boundary layer with the change of state trajectory until it converges to the sliding surface, thereby further improving the robustness of the system. Additionally, the hybrid SMC methods, such as fuzzy-SMC and neural network-SMC (NN-SMC), are avoided. A precise test platform based on digital signal processor (DSP) was implemented, and experimental results are shown to demonstrate the effectiveness and correctness of the proposed method.

Highlights

Permanent magnet linear synchronous motor (PMLSM) is an industry standard in fields such as microscale robotic, electronic assembly, machine tools and manufacturing [1], [2]
The control chip is TMS320 F2812 digital signal processor (DSP) produced by Texas Instruments with fast computation and a completely integrated motor peripheral circuit, which is specially designed for motor control
EXPERIMENTAL RESULTS AND ANALYSIS In order to verify the effectiveness of the proposed method, complementary sliding mode control (CSMC) with traditional saturation function in [23] and the hybrid controller (CSMC based on recurrent wavelet-based Elman neural network (RWENN)) in [25] are applied to the PMLSM servo system for the comparison of the control performance

Summary

Introduction

Permanent magnet linear synchronous motor (PMLSM) is an industry standard in fields such as microscale robotic, electronic assembly, machine tools and manufacturing [1], [2]. INDEX TERMS Permanent magnet linear synchronous motor (PMLSM), uncertainties, complementary sliding mode control (CSMC), saturation function, approach angle. By introducing the complementary generalized error transformation, Su and Wang proposed a complementary sliding mode control (CSMC) to replace the switching function of SMC to improve the tracking precision and reduce the chattering in [22].

Results

Conclusion