An adaptive extended fuzzy function state-observer based control with unknown control direction
Selami Beyhan · Pamukkale University Journal of Engineering Sciences · 2017
Inthis paper, a novel adaptive extended fuzzy function state observer-basedcontroller is proposed to control a class of unknown or uncertain nonlinearsystems. The controller uses Nussbaum-gain technique from literature to preventcontroller singularity with unknown control direction and the controller degreeof freedom is increased. A state observer which employs the adaptive extendedfuzzy function system to approximate a nonlinear system dynamics and estimatesthe unmeasurable state. The stability of closed-loop control system are shownusing Lyapunov stability criterion and Nussbaum function property. The proposedand conventional fuzzy system based controllers are designed to control aninverted pendulum in simulation and a flexible-joint manipulator in real-timeexperiment. The integral of absoulte error (IAE) of tracking, integral ofsquared error (ISE) of tracking and integral of required absolute controlsignal (IAU) performances are compared in applications. The aim of the paper isnot only to improve the tracking performances, but also to implement theadaptive extended fuzzy function based controller to a real-time system andconduct the tracking with unknown control direction.