Gain tuning method of closed-loop-injection low-order feedforward controller considering axis dynamics

Low-order feedforward controllers have attracted much attention in engineering applications due to their simple structure and easy implementation. This paper focuses on low-order feedforward controllers with closed-loop-injection architectures. Currently, the gain of this type of feedforward controller is tuned with the goal of accurately fitting the following error. However, due to the limited control bandwidth, the compensation signal generated by the feedforward controller cannot be fully responded to by the feed axis. This paper proposes a new gain-tuning method. It enhances the feedforward controller’s performance by considering the axis dynamics. The effectiveness of the proposed method is verified by experiments implemented on a two-axis bench. The results show that, compared with the method that does not consider the axis dynamics, the proposed method further reduces the following error and the trajectory error during trajectory tracking.