Dsp Based Adaptive Controller for Brushless Dc Motor Used in Robotic Applications

The paper deals with an adaptive speed controller design for a brushless DC motor drive. The controller structure include also a load-torque estimation approach in order to achieve a robust accurate path tracking. The design procedure is based on the fieldoriented control loop so as the controller itself will has two components: a two degree of freedom speed controller and a feed-forward load-torque compensator. The parameters of the first part are adjusted adaptively in terms of estimated model parameters, using a poleplacement technique. Estimating the model parameters entails a second-order least-squares estimator with constant trace to avoid estimator windup. The second component is based on an estimated load-torque model. In order to detect any slow or sudden changes of torque disturbance, a first-order least-squares estimator is used. Simulation and experimental results show that the proposed approach can achieve accurate velocity servo tracking in the presence of load disturbance and plant parameter variations.