Dynamic Adaptive Robust Backstepping Control Design for an Uncertain Linear System

This paper builds on the existing adaptive robust control (ARC) synthesis method introduced by Yao et al. and presents a new method to synthesize ARCs. Based on dynamic backstepping, the approach explicitly addresses the uncertain dynamics which enters into the system via the higher-order channels of the state-space model. As such, the proposed dynamic ARC (D-ARC) method addresses the inherent weakness of the original approach where uncertainty in the higher-order channels is ignored. The proposed approach is illustrated in simulations for controlling a voice coil motor (VCM) actuator that serves as a read/write head for a single-stage hard disk drive (HDD). The effectiveness of the resulting D-ARC controller is validated by considering the transient performance, tracking errors, and disturbance rejection of the VCM operating in both the track-seeking and track-following modes.