Fulwani, Deepak M

The study proposes a method to design a non-linear sliding surface to achieve better transient response for a class of single-input and single-output (SISO) non-linear uncertain system represented in a Brunowsky canonical form. The proposed surface can also be used for linear uncertain systems with matched perturbations. The proposed surface increases the damping ratio of the closed-loop system from its initial low value; as the output approaches the setpoint from its initial value. Initially, the system is lightly damped resulting in a quick response and as the output approaches the setpoint, the system is overdamped to avoid overshoot. The existence of sliding mode is proved and a new control law is proposed to enforce sliding motion. The scheme is able to achieve low overshoot and short settling time simultaneously which is not possible with a linear sliding surface. To ease the synthesis of the non-linear surface, linear matrix inequalities-based algorithm is proposed. Effectiveness of the proposed scheme is illustrated by the simulation results. © 2011 The Institution of Engineering and Technology.

A class of nonlinear uncertain systems with saturated actuator is considered in this paper. Sliding surface matrix is obtained using parameterized Riccatti equation. The proposed surface ensures that control limits are respected in a region of state space. This region can be made sufficiently large by choosing appropriate value of design parameters. © 2012 IEEE.

This chapter discusses two methods of designing a sliding surface in the face of an actuator saturation constraint for a class of nonlinear uncertain systems. The first approach uses an ARE based approach to design the sliding surface and the second approach uses the parametric Lyapunov equation to design the surface. These methods are based on the low gain approach proposed by Lin et al. The design methods give a surface matrix as a function of the designed parameter. This parameter can be modulated to reduce the control amplitude which ensures that the control limits are respected in a region of the state space. This region can be made sufficiently large by choosing appropriate values of the design parameter. © Springer-Verlag Berlin Heidelberg 2013.