Experimental and Simulation-based Investigation of a Velocity Controller Extension on a Ball Screw System

The background of this contribution is the enhancement of the achievable accuracy of servo-screw-presses. Therefore, the paper is concerned with the improvement of the dynamic precision for direct driven servo axes which is still restricted by structural vibrations. For this purpose, a ball screw test rig was analyzed for which the standard cascade control structure was extended by an additional velocity feedback. This structural extension has the potential to improve the controller performance significantly due to a better damping of low frequent vibrations. Furthermore, a parametric dynamic model for the control structure was derived to investigate the effects of the controller extension. For this analysis, the influences of the used tuning factors and filters is discussed in the frequency domain based on bode plots. The results of these cognitions are transferred to the time domain and illustrated by step responses. In addition, an evaluation by the criterion of the IAE (integral of absolute error) and the Prony analysis is carried out. Finally, the results are experimentally verified at the ball screw test rig. The paper closes with the conclusions.