Optimal nonlinear gain tuning of composite nonlinear feedback controller and its application to a hard disk drive servo system

This paper addresses the optimal nonlinear gain tuning methods for the composite nonlinear feedback (CNF) control law. The parameter tuning problem is formulated as an optimization problem, which can be solved efficiently via numerical methods. The parameters of the nonlinear function are tuned by solving the optimization problem. Moreover, a hard disk drive (HDD) servo system is designed by using the composite nonlinear feedback control with the proposed optimal nonlinear gain tuning method. The simulation and experiment results show that the control law designed using the new approach yields excellent performance for both track seeking and track following in the hard disk drive servo system.