A new adaptive control scheme for uncertain nonlinear systems with quantized input signal

In this paper,we propose a new simple yet effective adaptive tracking control scheme for uncertain strict-feedback nonlinear systems whose input is quantized by a class of sector-bounded quantizers including the well-known logarithmic quantizer and the extended hysteresis quantizer . To deal with the error caused by quantization, a key technique is to utilize the sector bound property of the quantizers directly instead of decomposing it into a linear part and a nonlinear part. Compared with the existing results in adaptive control, the proposed scheme relaxes the global Lipschitz conditions of nonlinearities and the boundedness of their partial derivatives. It is shown that the designed adaptive controller ensures global boundedness of all the signals in the closed-loop system and enables the tracking error to exponentially converge towards a compact set which is adjustable.