When is it reasonable to implement the discontinuous sliding‐mode controllers instead of the continuous ones? Frequency domain criteria

Professor Utkin proposed an example showing that the amplitude of chattering caused by the presence of parasitic dynamics (stable actuators) in some systems governed by the First‐Order Sliding‐Mode Controller is lower than that produced by the Super‐Twisting Algorithm. This example served to motivate this paper reconsidering the problem of comparison of chattering in systems with stable actuators, and driven by Discontinuous Sliding‐Mode Controllers (DSMCs) and Continuous Sliding‐Mode Controllers (CSMCs). Comparison of chattering produced by DSMC and CSMC taking into account their amplitudes, frequencies, and average power (AP) needed to maintain the system into real‐sliding modes, allowing to conclude the following: (i) for systems with slow actuators, the amplitude of oscillations and AP produced by DSMC be smaller than those caused by CSMC; (ii) for bounded disturbances with fixed Lipschitz constant, there exist sufficiently fast actuators for which the amplitude of oscillations and AP produced by CSMC be smaller than those caused by DSMC.     

Robust Adaptive Control of Pulse-width Modulated Rectifiers Based on Adaptive Super-twisting Sliding-mode and State Feedback Controllers

Abstract—This article proposes a new robust adaptive hybrid controller for three-phase pulse-width modulated rectifiers to improve control performance. This hybridization is implemented by combining the second-order sliding mode with the adaptive gain super-twisting control law in the DC bus voltage control loop and state feedback adaptive control in the d-q-axis current control loops. The control objectives are fourfold: (1) driving the DC bus voltage to a reference signal without using a priori knowledge of the plant parameters, (2) forcing the d-q-axis current errors to zero, (3) assuring a satisfactory power factor correction in relation to the AC source, and (4) eliminating the chattering effect. In the closed-loop control system, three-phase source currents and the DC bus voltage are supposed to be available for feedback. As a result, no a priori knowledge of the plant parameters is necessary in the design of the proposed controller. In addition, the proposed controller does not have the disadvantages of singularity, over-parameterization, and chattering phenomenon. Results of experimental studies prove that the proposed control system guarantees the tracking of reference signals with high performance despite all the parameter and external disturbance uncertainties.     

一种基于施密特触发器原理的直流电机位置控制及消抖算法

有刷直流电机的位置控制是一种常用的工作场景，对系统的响应速度、调节速度和控制精度等都有一定要求。经典的有刷直流电机位置控制算法一般都较理论，算法编写和调试较为复杂。基于现实应用需求，提出了一种新型的控制算法。该算法基于电子电路中施密特触发器的工作原理，实测具有响应速度快、控制精度较高、无抖动、适用范围广和编程简易等特点，可供相关技术人员参考借鉴。     

永磁直线同步电机插入式积分滑模控制

永磁直线同步电机(PMLSM)因具有高速、高动态响应等优点而备受关注。参数变化、端部效应和摩擦力等不确定因素将会降低直线电机控制系统应有的性能。为了提高系统的鲁棒性,提出了一种插入式积分滑模控制。该滑模控制将原有控制器的输出量加入到所设计的滑模面中,使得控制系统在不改变原有控制器结构和性能的情况下,获得较强的鲁棒性。同时,以连续的超螺旋控制替换积分滑模控制中原有的不连续部分,削弱了滑模固有的抖振。MATLAB/Simulink仿真结果证实了所提方法的有效性。     

基于扰动观测和补偿的PMSM伺服系统位置跟踪控制

针对存在参数摄动和外部扰动力矩的PMSM伺服系统位置跟踪控制问题,提出一种基于扰动观测和补偿的滑模控制方法。采用扰动观测器估计系统参数摄动以及负载力矩,并在此基础上对等效扰动进行补偿,减小了模型不确定性对系统控制性能影响,系统的位置跟踪误差由0.85 rad减小到0.35 rad;在保证系统稳定性的前提下,去除了常规滑模控制中的不连续控制项,有效地减小了抖振。实验结果表明,与工程上常用的PID算法相比,基于扰动观测和补偿的滑模控制算法不仅能够显著提高PMSM伺服系统的位置跟踪精度,而且能有效地削弱抖振。     

Chattering‐free adaptive sliding mode control for continuous‐time systems with time‐varying delay and process disturbance

This paper concerns the controller design for continuous‐time linear systems with time‐varying delay and process disturbance. A novel adaptive sliding mode control law is mainly proposed to attract the sliding mode to first‐order sliding surface within a finite time; afterwards, the uniformly ultimately bounded stability of the closed‐loop system on the sliding surface is simultaneously guaranteed. In addition, the chattering phenomena can be conveniently excluded if the disturbance is a low‐intensity process. Once the high‐intensity disturbance is involved, the state variation can be significantly reduced as well. Furthermore, by the technique of a novel exponential free‐matrix technique, the convergence rate of the closed‐loop system can be conveniently preregulated. Numerical example is provided to demonstrate the effectiveness of the proposed method.     

积分滑模控制及抖振抑制研究用于仿人机器人头部控制

介绍了HIT三自由度仿人机器人头部的机械和电气结构,将积分滑模控制算法应用于头部追踪控制,实现了对闭环系统极点的任意配置,克服了建模不准确、外部干扰等因素的影响,使滑动模态发生在运动初始时刻,并贯穿于整个响应过程。同时提出了一种简单易行的方法切换函数比例法来抑制积分滑模控制的抖振。经与传统的PID加摩擦力补偿控制和基于计算力矩法的滑模变结构控制对比,实验证明了提出的控制方法具有较高的跟踪精度并且抖振较小、抗干扰性较强。     

终端滑模控制方法研究进展

总结了终端滑模、快速终端滑模、非奇异终端滑模及指数型终端滑模等不同形式的终端滑模的研究状况,指出了各种终端滑模的优缺点及改进方法,分析了抖振消减方法,研究了各种终端滑模控制的应用,分析了终端滑模控制的发晨方向.     

基于变结构控制的导弹倾斜转弯技术研究

针对导弹倾斜转弯过程中存在的大参数不确定性，强气动耦合的情况，利用变结构控制方法在一定范围内具有鲁棒性的特点，设计了满足参数不确定性限制及耦合抑制的一种基于变结构控制方法的自动驾驶仪，并对变结构方法本身存在的抖振问题进行了研究。将本文研究的方法应用于某导弹的自动驾驶仪设计中，仿真结果表明，驾驶仪能迅速准确跟踪指令，耦合得到有效消除，抖振得到有效抑制。