An adaptive reaching law of chattering‐free discrete‐time sliding mode control for systems with external disturbance

Abstract

An adaptive reaching law of chattering‐free discrete‐time sliding mode control is proposed for the systems with external disturbance. An adaptive function is proposed in the reaching law which can increase reaching speed as sliding variable is far away from zero and avoid undesired chattering when sliding variable is close to origin. Moreover, a third‐order backward difference of disturbance is added to obtain a narrower quasi‐sliding mode band (QSMB). Both the closed‐loop system performance and finite reaching steps to achieve the desired QSMB are theoretically analyzed. The simulation results verify the effectiveness of the proposed control strategy.

Adaptive non‐singular fast terminal sliding mode based on prescribed performance for robot manipulators

“…It has higher convergence accuracy and robustness to disturbances [19]. However, SMC and TSMC have more room to improve control performance, such as the singularity problem [20][21][22][23] and the chattering phenomenon [24][25][26][27], which are caused by the higher control gain coefficient and switching on the sliding surface that make robot manipulators unstable. Feng et al formulated a non-singular terminal sliding mode controller (NTSMC) to eliminate the singularity caused by TSMC [20].…”

A control strategy for variable‐speed variable‐pitch wind turbines within the regions of partial‐ and full‐load operation without wind speed feedback

“…However, advanced control techniques have being exploited to design high performance WT controllers, and a comprehensive overview of variable-speed WECSs is reported in Njiri and Soffker [1]. For instance, nonlinear, optimal, fuzzy logic, neural network-based, adaptive, decentralized multivariable, and sliding mode control strategies have been recently reported in the literature [13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Most of the proposals are confined to either partial- [20,21,23,[27][28][29] or full-load [30][31][32][33][34] operation, while only a few cover a wide operating range [9,17,18,22,[35][36][37][38].…”