Robust output tracking of a class of non-affine systems

• Main Authors: Tahereh Binazadeh, Mohammad Ali Rahgoshay
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2017-01-01
• Series: Systems Science & Control Engineering
• Subjects: Non-affine quadratic polynomial systems; robust output tracking; sliding mode; magnetic ball levitation system
• Online Access: http://dx.doi.org/10.1080/21642583.2017.1376296

This paper considers the robust output tracking problem for a class of uncertain non-affine systems. The state-space equations of these systems have a non-affine quadratic polynomial structure. In order to design the output tracking controller, first the error dynamical equations are constructed. Then, a novel sliding mode controller is designed for robust stabilization of the error dynamical equations. For this purpose, a proper sliding manifold which is a function of error vector is suggested. According to upper and lower bounds of uncertainties, two quadratic polynomials are built and with respect to the location of the roots of the given polynomials, the new sliding mode control law is obtained. The proposed controller can conquer the uncertainties and guarantees the asymptotic convergence of the system output toward the wanted time-varying reference signal. Finally, in order to verify the theoretical results, the proposed method is applied to the magnetic ball levitation system. Computer simulations demonstrate the efficiency of the proposed method.