Control of a 2-Link Flexible Arm. 2nd Report, Evaluation of the Robust Stability against Variations of an Arm's Configulation and a Tip Mass and Related Experiments.

Abstract

An active damping control method has been applied to achieve quick positioning for a 2-link flexible manipulator. The 2-link flexible manipulator is regarded as a distributed parameter model in consideration of the mutual interaction between links. A 6-input, 2-output LQG controller was adopted as the active damping controller to avoid coupled vibration. Then the robustness against variations of the arm's configuration and its tip mass were evaluated in the time and frequency domain. Also evaluated was how a nominal arm model in the LQG controller design should be set to maintain stability against wider variations. These evaluation results have been confirmed by experiments. As a result, (1) it was impossible for the LQG controller to maintain stability beyond the boundaries of the arms configuration, and (2) a LQG controller designed with the arm model of maximum tip mass was able to maintain stability against wider variations of the tip mass.