QFT based control of a single-link flexible manipulator with hybrid actuation

Abstract

This paper presents the development of a robust control scheme based on the Quantitative Feedback Theory (QFT) methodology for vibration and position tracking control of a slewing single-link flexible manipulator with hybrid actuation. The manipulator employs a DC motor for high-authority discrete actuation at the hub and a piezoelectric actuator for low-authority distributed actuation along the flexible link. The manipulator payload conditions are varied to assess the robustness of the synthesised control system to uncertainty. QFT is used to synthesise robust controllers by converting the multi input multi output (MIMO) problem into two equivalent multiple input single output (MISO) design problems. The QFT MIMO design method is shown to synthesise a control system that satisfies time domain specifications on the system and is robust to system uncertainties with minimal 'cost of feedback'. The effectiveness of the combined hybrid actuator control scheme (HACS) and robust control system is demonstrated via simulation of the tracking performance. The transparency of the QFT synthesis procedure highlights the tradeoff in the control system design between fast angular rotation and low levels of link vibration.