Adaptive control design for unknown system with nonlinear perturbed dead-zone

Adaptive control design is studied for a class of unknown systems with a nonlinear perturbed dead-zone input. The nonlinear dead-zone can be represented as a time-varying system with a disturbance-like term. An adaptive controller is first constructed using functions acting as the upper bounds of the nonlinear dynamics, which are independent on the dead-zone parameters. Time-varying delays are also dealt with while the construction of an inverse dead-zone model is not required. Moreover, a neural controller is further proposed using a neural network with only a scalar weight parameter, such that the requirement on the bounds functions can be relaxed. The effectiveness of the developed approaches is illustrated by simulations.