Robust controllers design of constant turning force feedback control system

In this paper, several design methods are proposed to deal with the constant turning force feedback control system against the nonlinear time-varying gain perturbation in the cutting process. The proposed methods include minimum weighted sensitivity robust control, robust-linear quadratic sub-optimal PI control and robust linear quadratic optimal control. The simulation results show that these design methods can achieve satisfactory system stability and performance and achieve superior performance responses to the classical PI control