Minimum-time positioning and saturation avoidance via optimal trajectory algorithm for high performance industrial servodrives

This paper presents and evaluates a novel on-line optimal trajectories generator algorithm for high performance industrial servodrives. In order to completely avoid current saturation, the optimal trajectories are calculated considering the maximum speed and current constrains, the inertial torque component and the load torque estimated by a disturbance observer. Using this information, optimum acceleration and deceleration profiles are computed to reach the desired position in minimum time. The proposed algorithm is applied to a standard cascade position control topology generating the optimal position, speed and acceleration commands required for feed-forward controllers The effectiveness of the proposed algorithm is evaluated using an experimental setup, showing a fast and smooth response and a considerable reduction of total time positioning.