On the dynamic and steady errors in sampled data quasi-sliding modes

The nonideal behavior of sampled data quasi-sliding mode controllers (SDQSM) gives rise to dynamic and steady errors in closed-loop controlled systems. The authors propose analytical methods to describe these errors. Some design corrective procedures are proposed in order to minimize or eliminate these errors. The closed-loop SDQSM system is modeled as an autonomous system driven by state and parameter bounded perturbations, thus taking into account these errors. Simulation results are presented. These errors are shown to depend on three factors: the sampling interval, the unbalancing factor, and the absolute system velocity. Corrective procedures are proposed on the basis of these dependencies