Improved robustness and performance of discrete time sliding mode control systems.
This paper presents a theoretical analysis along with simulations to show that increased robustness can be achieved for discrete time sliding mode control systems by choosing the sliding variable, or the output, to be of relative degree two instead of relative degree one. In other words it successfully reduces the ultimate bound of the sliding variable compared to the ultimate bound for standard discrete time sliding mode control systems. It is also found out that for such a selection of relative degree two output of the discrete time system, the reduced order system during sliding becomes finite time stable in absence of disturbance. With disturbance, it becomes finite time ultimately bounded.
Department of Electrical Engineering, Indian Institute of Technology Roorkee, India. Electronic address: sohomfee@iitr.ac.in.
Sohom
S
Chakrabarty
Institute of Automatic Control, Technical University of Lodz, Poland. Electronic address: andrzej.bartoszewicz@p.lodz.pl.
Andrzej
A
Bartoszewicz
Discrete time sliding mode control; Finite time convergence; Relative degree; Robustness; Ultimate band