Adaptive speed/position control of induction motor with unknown load torque

The paper proposes an adaptive speed/position tracking control of an induction motor subject to unknown load torque. The controller is developed based on a dynamic model obtained from the d-q-axis model (w.r.t. the stationary reference frame) of the motor under a special nonlinear coordinate transform so that either the speed or position control objective can be fulfilled. The underlying design concept is to endow the close-loop system with the so-called maximal power transfer property while under lack of knowledge of some key system parameters, such as the rotor resistance, motor inertia and motor damping coefficient. To be rigorous, we present a thorough proof of the proposed control scheme based on Lyapunov stability theory. Experimental results are also given to validate the effectiveness of the scheme.