Disturbance Observers for a Class of Hysteresis Nonlinearities Available to Purchase

This paper addresses performance enhancement using disturbance observers for a class of hysteresis nonlinearities. The proposed approach makes use of internal model-based estimation of exogenous disturbances. The synthesis is then formulated as an H_∞ weighted-sensitivity optimization for static output feedback (SOF) gain of a Luenberger observer. A sequential linear programming approach is then implemented to solve the bilinear-matrix-inequality (BMI) constrained semi-definite program (SDP) for the (sub)optimal static gain. Simulation results indicate that tracking performance is indeed enhanced using the DOB at different excitation frequencies in the closed loop control system.