A real-time estimation method of brushless DC servomotor parameters

This paper deals with an estimation method of the load inertia/torque, cogging torque, winding resistance and back-EMF constant of a brushless DC servomotor operating in a system. The method requires no modification of the system hardware, as the quantities needed for estimation are the winding current, applied voltage, motor speed and rotor position, which can all be taken from the connectors of a normal driver or controller. Time required for data acquisition and computation is discussed for applying this technique to construct a controller capable of coping with varying inertia and load torque.