Modeling and Controller Tuning Techniques for Feed Drive Systems

Abstract

In this paper, a new modeling, and controller tuning method for feed drive systems is described. Typical feed drive systems consist of an AC servo motor, a ball screw, linear guides, and a servo controller. In order to design high performance systems, it is effective to make a model and analyze its behavior. In this study, a feed drive system is modeled by a vibration model with two degrees of freedom. Various kinds of motions are measured and simulated. The results of the experiment and simulation show that these motions are well simulated by the model. This means that the proposed model can accurately estimate the transfer function of the actual system. As a result, it is easy to design a controller based on the transfer function. The gains in the velocity control loop are calculated based on the partial model-matching method. Two PI and I-P velocity controllers are applied to the feed drive system. The step responses are then compared to each other. The position loop gain is calculated from the frequency response of the velocity control system. The proposed method is applied to an actual feed drive system, and it is confirmed that the proposed method yields comparable performance to the system designed by the conventional tuning way.