Improvement of a novel dual-stage large-span track-seeking and track-following method using anti-windup compensation

A recently developed large-span track-seeking and track-following method for dual-stage actuator systems is improved in terms of settling duration, recovery from saturation in the secondary actuator loop and design flexibility by incorporating an anti-windup (AW)-compensation scheme. The developed large-span track-seeking and track-following controller is based on a well-known method which allows the decoupling of the secondary micro-actuator loop from the primary VCM-loop in terms of stability and design. For the originally suggested method, micro-actuator saturation was addressed using the circle criterion to guide the controller design for this loop. However such an approach does not allow the fine-tuning of seeking and settling speeds and also limits the class of linear controllers for the secondary loop. This paper suggests the use of an anti-windup compensator, based on an L-2-optimization approach and computed using linear matrix inequalities (LMI's), to cope with the saturation issues in the secondary loop, allowing full freedom in the initial linear controller design. The suggested approach is demonstrated using a PZT-actuated suspension and a commercial VCM-actuator.