Abstract:

The problem of variable control for discrete-linear systems was discussed. A new discrete reaching law was presented   to deal with the flaw which exits in the conventional variable structure reaching law method. The sliding mode determined by this reaching law could be divided into two areas in the reaching process and the sliding mode trajectory could be converged to zero. The different reaching characteristics of the sliding mode trajectory were considered. The width of two areas might be changed by the adjustment of control parameters so that it enabled the sliding mode trajectory to pass through the switch surface as little as possible, thus the guarantee of control system chattering weakening and robustness was achieved. Good robustness of the discrete variable controller designed by this reaching law was proved. The simulation results  showed the superiority of this discrete reaching law method for nominal systems and good control performance for uncertain systems.

Key words:  discrete variable control, chattering weakening, robustness, discrete reaching law