College of Information Engineering, Zhejiang University of Technology
The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan); The Natural Science Foundation of Zhejiang Province
本文针对带有摩擦力矩、负载力矩以及扰动力矩等不确定性的机电伺服系统, 提出一种基于变速趋近律的自适应滑模控制方法. 首先, 构造双曲正切型辅助函数并设计新的变速趋近律, 用以调节滑模变量的收敛速度, 使其在到达减速点之前具有较快的收敛速度, 而在到达减速点以后则能有效削弱抖振. 在此基础上, 构造自适应滑模控制器, 保证系统位置输出能够快速稳定地跟踪期望轨迹. 同时, 设计参数更新律估计不确定项平方的上界, 确保控制信号的连续性和减小控制信号抖振. 基于李雅普诺夫稳定性定理给出误差收敛性分析, 并给出仿真对比验证本文所提方法的有效性.
In this paper, a variable rate reaching law-based adaptive sliding mode control scheme is proposed for electromechanical servo systems with lumped uncertainties including friction torque, load torque and disturbance torque, etc. Firstly, a hyperbolic tangent auxiliary function is presented to construct a novel variable rate reaching law, which can adjust the convergence rate of the sliding mode variable. With the proposed reaching law, a faster convergence rate is achieved before reaching the deceleration point, and the chattering issue can be reduced after the deceleration point. Then, an adaptive sliding mode controller is designed to guarantee that the system position output can track the desired trajectory quickly and stably. Meanwhile, parameter updating laws are developed to estimate the upper bound of the square of the uncertainties, and thus the continuity of the control signal and the reduction of the chattering are both guaranteed. The error convergence performance of the proposed scheme is analyzed through the Lyapunov stability synthesis, and comparative simulation results are given to validate the effectiveness of the proposed scheme.