Quantized feedback control for nonlinear feedforward systems with unknown output functions

The quantized feedback control is investigated for nonlinear feedforward systems with unknown control coefficients, unknown output functions and input quantization. The unknown output function is Lipschitz continuous but may not be derivable, the unknown control coefficients are assumed to be bounded, and the input quantization is logarithmic. By combining the backstepping method and the sector bound approach, a time-varying quantized feedback controller is designed and a guideline for choosing the parameter of the input quantizer is provided to guarantee the boundedness and convergence of the closed-loop system states. Finally, a simulation example is presented to show the effectiveness of the control scheme.