Controller design and robustness analysis for induction machine-based positioning system

This paper considers the design of a robust controller for the automatic positioning of a mechanical load actuated by an induction motor. Two main difficulties are involved herein: the first concerns the flexibility that appears in the joint between the load and the actuator; and the second focuses on the robustness to uncertainties, such as load and motor parameters. Based on a nominal model, the H_∞ "loop-shaping" method is used to design a controller that allows both insuring effective monitoring properties and rejecting perturbations. In order to prove robustness to parametric variations, a μ-analysis of the control pattern has been conducted. The ad hoc model developed includes uncertainties on both electrical and mechanical parts. Simulation and experimental results have been incorporated to display the control law performance.