Modified linear quadratic optimal control method and application in linear brushless direct current motor

Linear quadratic optimal control (LQ) has great gain margin phase margin and good nonlinear allowance. Time-domain analysis and frequency-domain analysis are the basic approaches in designing control system and they have close relationship to each. However, the linear brushless direct current motor (LBDCM) is greatly affected by the uncertainties of the plant, the performance deviates far from the nominal design. In order to improve the performance of LBDCM, the paper presents a method of modified linear quadratic optimal control. The simulation results verified the validity of the scheme.