Adaptive robust controller is proposed for read/write head systems for hard disk drives (HDD). This structure can be applied to both track seeking and track following modes, and it makes the mode switching control algorithms found in conventional HDD servo system unnecessary. A discontinuous projection based on adaptive robust controller (ARC) is considered first. This controller theoretically guarantees a prescribed transient performance and tracking in presence of parametric uncertainties. An improved desired compensation ARC scheme is then presented, in which the regressor is calculated using reference trajectory information. This has been done by structural vibration minimized acceleration trajectory control method (SMART). The resulting controller has several implementation advantages such as less online computation time, less vibration, reduction of noise measurement effect, separation of robust control design from parameter adaptation, and a faster adaptation rate. The simulation and comparison results are presented to illustrate the effectiveness and the achievable control performance of the proposed controller algorithm.