The Direct drive electro-mechanical actuator (EMA), which uses the permanent magnetic synchronous motor (PMSM) as the driver, requires that the motor position control system must be precise, robust, and have outstanding load disturbance rejection ability. To meet these requirements, practical controllers based on active disturbance rejection control (ADRC) techniques were presented. First, to implement the vector control of id = 0 and follow-up control of q-axis current respectively, linear error feedback control strategies were adopted and disturbances, which were introduced by cross coupling of d-axis and q-axis current and perturbation of electrical parameters, were estimated by the Expanded State Observer(ESO) and then compensated. Second, for the position control system, tracking differentiator was employed to arrange the transition process of the position response; And then, states and total disturbance of load and friction torque were estimated by ESO; Eventually, states feedback control strategy and disturbance feed-forward compensation were implemented to complete the angle position control which embraces the inner q-axis current control system. Simulation and experimental results verified that the feasible ADRC-based PMSM servo system was fast, precise, of no overshoot, strongly robust to load disturbance and easy to be implemented.
