Remarks on some robust nonlinear observer and state-feedback zero-bias control of AMB

This paper reports on novel nonlinear observer for a flux-controlled active magnetic bearing (AMB). Also a nonlinear state-feedback control law is designed for AMB in zero-bias mode due to voltage saturation. The nonlinear reduced-order observer is designed, to estimate the flux, and incorporated in equivalence implementation of the nonlinear state-feedback controller. The main design tools such as sliding mode control, Control Lyapunov Function (CLF) and passivity are used in this framework. Numerical simulations show the effectiveness of the proposed observer-feedback and state-feedback designs.