Practical equivalent control in 2-sliding controls applied to an anthropomorphic robot arm

Driving an anthropomorphic robot arm driven by pneumatic artificial rubber muscles (PARMs) with a direct transmission is quite delicate. PARMs present complex nonlin-earities and robust control tools are unevitable. Among them, those applied are the twisting and super twisting algorithms, which belong to the 2-higher order sliding mode control set. In this paper it is studied the effect of the equivalent control in sliding mode controller based on variable structure systems (VSS) theory. It will be shown when to use the equivalent control, and the effects of a noisy sensor signal on control performance. Experimental results are presented and discussed.