Adaptive fuzzy logic compensation of actuator deadzones

A deadzone compensator is designed for nonlinear systems using a fuzzy logic (FL) controller. The classification property of FL systems makes them a natural candidate for the rejection of errors induced by the deadzone, which has regions in which it behaves differently. A tuning algorithm is given for the FL parameters so that the deadzone compensation scheme becomes adaptive, guaranteeing small tracking errors and bounded parameter estimates. A rigorous proof of stability and performance is given and a simulation example verifies excellent performance. It is seen that the extra signal produced by the adaptive FL deadzone compensator can be considered as an adaptive dithering term.