Fractional-order sliding mode based extremum seeking control of a class of nonlinear systems

• Published in: Automatica (Oxford) Vol. 50; no. 12; pp. 3173 - 3181
• Main Authors: Yin, Chun, Chen, YangQuan, Zhong, Shou-ming
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.12.2014; Elsevier
• Subjects: Applied sciences; Computer science; control theory; systems; Control systems; Control theory. Systems; Convergence; Convergence speed; Derivatives; Dynamical systems; Energy; Exact sciences and technology; Fractional-order sign function; Modelling and identification; Natural energy; Nonlinear dynamics; Optimization; Photovoltaic conversion; Photovoltaic power plants; Photovoltaic system; Simulation; Sliding mode; Sliding mode based extremum seeking control; Solar energy; Tracking; Fractional-order sign function; Tracking; Sliding mode based extremum seeking control; Photovoltaic system; Convergence speed; Extreme search; Variable structure control; Mode control; Sliding mode; Non linear control; Tracking task; Non linear programming; Experimental study; Non linear system; Fractional derivative; Extremum problem; Photovoltaic power plant; Source localization; Tracking(movable target); Function derivative
• ISSN: 0005-1098; 1873-2836
• DOI: 10.1016/j.automatica.2014.10.027

This paper develops a fractional-order sliding mode based extremum seeking controller (FO SM-ESC) for the optimization of nonlinear systems. The proposed FO SM-ESC, involving an FO derivative function 0Dtqsgn(e),0≤q<1 is shown to achieve faster tracking and higher control accuracy than the integer-order (IO) SM-ESC. The tradeoff between control performance and parameters selection is analyzed and visualized. The comparison between the FO/IO SM-ESC is given to reveal the potential advantages of the FO controller over the IO controller. Simulation and experimental results show that the FO SM-ESC can have a faster convergence speed and a smaller neighborhood around the optimal operational point.