Adaptive fuzzy control of MIMO nonlinear systems with unknown hysteresis and control gain matrix sign

In this paper, a fuzzy adaptive control system is investigated for a class of uncertain multi-input multi-output (MIMO) nonlinear systems with both unknown backlash hysteresis and unknown sign of the control gain matrix. To deal with the unknown sign of the control gain matrix, the Nussbaum-type function is used. In the designing of the fuzzy adaptive control scheme, we will exploit a decomposition property of the control gain matrix. To compensate the effects of the backlash, we require neither the knowledge of backlash parameters nor the construction of its inverse.