No abstract

The brushless dc motor position tracking system to be controlled includes a friction and a backlash as disturbances. In this paper, we propose a robust linear quadratic sliding-mode controller for precision positioning in a brushless dc motor system. The control algorithm includes a linear quadratic control for an optimal feedback gain and an integral nonlinear sliding-surface based on a new reaching law to remove the reaching phase. It has robust performance against parameter variation which causes an oscillation in case of linear quadratic control. Simulation results show that the proposed controller gives an improved accurate driving tracking result and is robust to plant parameter variation and load torque disturbances.