Adaptive Feedforward Cancellation for Precise Repetitive Motion in Coarse-Fine Control System

Abstract

This paper introduces a novel control scheme to achieve precise repetitive motion within a dual-input-single-output (DISO) system consisting of course-actuator and fine-actuator. Repetitive motion stands as a crucial operation in various applications, particularly in manufacturing processes. Designing a control system capable of accurately tracking reference signals during repetitive motion is imperative for DISO systems. The proposed method focuses on adaptive feed-forward cancellation (AFC) to effectively compensate for position error signals related to the reference signal. A typical control scheme implements AFC for the entire control loop. In the control system, the same characteristic of AFC works for both actuators in the DISO control system. The same AFC output is working to both actuators. On the other hand, the proposed control scheme implements AFC to each actuator. It can generate suitable AFC output for the course-actuator, fine-actuator, respectively. That is, the major contribution of proposed control scheme individually optimizes the AFC in the course-fine control system. This design approach significantly enhances the control performance of DISO systems, considering the distinctive characteristics and stroke limitations of the actuators. Experimental implementation of the proposed control system validated its efficacy, affirming the improvement of control performance in DISO systems.

Keywords

• Dual-input-single-output (DISO) system
• repetitive control
• adaptive feedforward cancellation
• loop shaping