The problem of designing sliding-mode observers for systems with unknown inputs is considered when the so-called observer matching condition is not satisfied. This condition severely restricts the applicability of sliding-mode observers. To circumvent the observer matching condition, thereby broadening the class of systems for which sliding-mode observers can be constructed, a possible method i...

An improved sliding mode observer is presented to estimate the rotor position of the permanent magnet synchronous motors (PMSMs). In this observer, the discontinuous control is replaced by using the sigmoid function in order to reduce the chattering problem commonly found in the conventional sliding mode observer. When the chattering is reduced, the back emf can be obtained directly from the sw...

Abstract: Presented is a method of continuous sliding mode control design to provide for the second-order sliding mode on the selected sliding surfaces in a three-loop control system, where two outer-loop virtual control signals must be smooth enough to be tracked in the inner loops. The control law in the vicinity of the sliding surface is a nonlinear dynamic feedback that in absence of unknow...

This article develops a new output feedback tracking control scheme for uncertain robot manipulators with only position measurements. Unlike the conventional sliding mode controller, a quasi-continuous second-order sliding mode controller (QC2C) is first designed. Although the QC2C produces continuous control and less chattering than conventional sliding mode and other high-order sliding mode c...

This paper presents a new observer based fuzzy terminal sliding mode controller design for a class of fractional order nonlinear systems. Robustness against uncertainty and disturbance, the stability of the close loop system and the convergence of both the tracking and observer errors to zero are the merits of the proposed the observer and the controller. The high gain observer is applied to es...

This paper presents a discrete sliding mode observer (DSMO) for state estimation of a class of a second order underactuated system. The estimated states are used to implement the discrete sliding mode control (DSMC). Modified Bartoszewicz’s reaching law is used to synthesize a DSMC. A partially filled liquid container motion coupled with liquid slosh constitutes a class of second order underact...