Invariant Manifold Based Output-Feedback Sliding Mode Control for Systems With Mismatched Disturbances

Abstract

This paper proposes an invariant manifold based output-feedback sliding mode control (SMC) strategy for systems with mismatched disturbances to achieve asymptotic tracking and disturbance rejection. Different from the existing outputfeedback SMC methods, the invariant manifold is employed to transform the multiple mismatched disturbances into matched ones, which can provide full system dynamics for controller design to improve accuracy. An observer is developed to estimate unmeasurable states, then an output-feedback sliding mode controller is proposed. Moreover, the switching gain of the controller adaptively changes with the estimation error, which reduces chattering in SMC. Experiments on a converter-driven DC motor system verify the superiority of the proposed method.

Sliding mode output feedback control for continuous systems without rank constraint

“…The straightforward way is to design the conventional state estimators to obtain the state estimates, which are implemented instead of states in the state feedback sliding mode controllers. [10][11][12] Instead of designing state estimators, the high gain observers with constant or time-varying gains can be used to design sliding mode output feedback controllers. 13,14 For systems with arbitrary relative degree, the higher-order sliding mode (HOSM) differentiators can be employed to design the sliding mode output feedback controllers.…”

“…Generally, there are some typical strategies to get around this issue. The straightforward way is to design the conventional state estimators to obtain the state estimates, which are implemented instead of states in the state feedback sliding mode controllers 10‐12 . Instead of designing state estimators, the high gain observers with constant or time‐varying gains can be used to design sliding mode output feedback controllers 13,14 .…”

Disturbance observer-based fixed-time control for nonlinear systems with multiple disturbances

“…Disturbances widely exist in actual engineering systems, which brings unfavorable effects on system performances; thus, antidisturbance problems have become one of research highlights (Hao et al, 2019;Wei et al, 2016Wei et al, , 2020Yao et al, 2021;Zhang et al, 2017Zhang et al, , 2021. Due to the superiorities of higher accuracy, stronger flexibility, and simpler structure, disturbance observer-based control (DOBC) has been extensively applied to deal with disturbances (Han et al, 2017;Javaid and Dong, 2021;Zhou et al, 2023).…”

Output-Feedback Sliding Mode Control for Permanent Magnet Synchronous Motor Servo System Subject to Unmatched Disturbances

“…Actually, the output-feedback SMC for PMSM servo system subject to unknown load torque disturbances is a challenging problem, since it is difficult to estimate both the unmeasured states and the unmatched disturbance at the same time. Reference [35] gives a new idea for outputfeedback SMC design, which combines SMC with the basic idea of output regulation theory [36,37]. Inspired by [35], this paper aims to solve the output-feedback SMC problem for PMSM servo system subject to unmatched disturbances.…”

“…Reference [35] gives a new idea for outputfeedback SMC design, which combines SMC with the basic idea of output regulation theory [36,37]. Inspired by [35], this paper aims to solve the output-feedback SMC problem for PMSM servo system subject to unmatched disturbances. Under the proposed controller, the angular velocity is driven to track the reference signal asymptotically.…”