Dynamic compensator-based second-order sliding mode controller design for mechanical systems

For mechanical systems using displacement measurements only, this study presents a dynamic compensator-based second-order sliding mode control algorithm without using any observer structure to estimate the velocity. Introducing the compensator into the sliding variable, a modified asymptotically stable second-order sliding mode control is developed. The proposed low-order dynamic controller inherently has low-pass filter property in which the effect of differentiators can be obtained. Using singular perturbation theory, the authors show that the system state is finally constrained in a small bound region when the gain is high enough. Finally, a numerical example is explained for demonstrating the applicability of the proposed scheme.