Performance of linear decentralized H∞ optimal control for industrial robotic manipulators

Industrial manipulators are under various limitations against high quality motion control, for example friction and dynamic uncertainties, and simple control structure. A robust linear PID motion controller, called the reference error feedback, is proposed, which solves the nonlinear L₂-gain attenuation control problem. Making use of the fact that the single parameter L₂-gain γ controls the performance and robustness, we propose a simple and stable method of tuning the controller called the “square law”. The analytical results are verified through experiments of six degrees of freedom industrial manipulator