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 Lscr₂ -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