Servo control of VCM driven pointing mirror based on command filtered adaptive backstepping

In this paper, we present an adaptive servo controller for the voice coil motor (VCM) driven pointing mirror with parameters uncertainties. Based on the mathematical model of the VCM, the design procedure is divided into three parts, namely the position loop, angular velocity loop and the current loop, an adaptive backstepping method is applied for the controller design against the parameter uncertainties, the design procedure utilizes the filters to generate the command control variables and their derivatives which can avoid the complexity caused by the needs for computing the derivatives of virtual control variables at each iterative step, especially when the order of the system goes high, the computing burden will increase explosively. So as to reduce the filtered error, a compensation loop is constructed based on the tracking error dynamic. The parameter adaption laws and robust terms are designed through Lyapunov stability analysis to guarantee asymptotic stability for the close-loop. Finally, the simulation results are presented to illustrate the effectiveness of the proposed control scheme.