Preview Control of Dual-Stage Actuator Systems for Superfast Transition Time

Abstract

This paper introduces a preview control design method to reduce the settling time of Dual-Stage Actuators (DSA). A Dual-Stage Actuator system is comprised of two actuators connected in series, a primary (coarse) actuator, and a secondary (fine) actuator. The objective of the proposed design is to account for the redundancy of actuators and use the information of future reference levels in order to compute a pair of inputs to be applied before the output transition time. Experimental results show that the proposed design method significantly reduces the output transition time when compared to a conventional form of DSA control design.

Control Methods in Data-Storage Systems

“…Dual-stage actuators are found in some products, primarily enterprise drives, even though their costs and limitations have so far prevented their widespread use. Sophisticated control design approaches and architectures have been employed for seeks and track following [111] and [112], whereas the simple approach of phase stabilization has greatly improved the performance of servo systems. Newer work on preview control may significantly improve seek performance, particularly for dual-stage systems.…”

Optimal preview control: A review

“…The current decade literature has presented new structure, systems, and generalizations in the design of preview control. The solution to preview control design problem is proposed for nonminimum phase systems, linear descriptor discrete‐time systems, and systems with stochastic parameter uncertainties . The classical solution of H ∞ preview control design is generalized for both previewable and unpreviewable disturbances, also .…”

“…The Preview Control has gained utilization in the field of process control and commercial application in the control design of servomechanism , two cascaded tank system , three‐phase induction motor , electromechanical valve actuator , wide speaker band system , drum‐type coal excavator , and turbine and wind turbine tower control . Preview control is widely used in improving performance and control of vehicles in the form of vehicle rollover protection , active vehicle suspension , driver assistance system , lane keeping assistance , hydraulic active suspension , and dual‐stage actuator design. The ability of the autonomous vehicles to track a programmed route improves substantially with Preview Control.…”

Continuous Preview Control of Dual-Stage Actuator systems for reduced transition time

“…This controller, however, does not always satisfy the constraints (3) - (5). Moreover, at the instants t = 0 and t = t S there will be switchings from the PTOS controller (u 1+ ) to preview controller (u 1− ) and vice verse, which may cause discontinuity in the overall controller (7). Theorem 3.1 shows that with a proper choice of the preview time τ and the final velocity v τ , the controller (10) not only satisfies the constraints but also provides a continuous switching between the preview controller and the PTOS controller.…”

“…As shown in Fig. 1, we take advantage of this extra degree of freedom provided by the secondary actuator and allow the primary actuator to move ahead of time [7]. The main contribution of the paper is the development of this pre-actuation strategy based on the immediate future reference point in order to reduce the settling time of the system.…”