Model based control of a multidimensional positioning system - a comparison of controller designs with experimental validation

The present study investigates the controlled behavior of a multidimensional positional system (MPS), under the application of model based control techniques (lead-lag, LQR, LQG, LQG-LTR, H_∞, μ-synthesis and QFT). The MPS consists of a magnetically levitated system capable of six degree-of-freedom micro and nano positioning using three novel permanent-magnet linear motors. Each motor generates a vertical force for suspension against gravity and a horizontal force for drive. Particular attention is given to the design, analysis and simulation of the control laws that guarantee tracking performance under modeled uncertainties. Closed loop identification is used to derive bounds of the variations in magnitude of the experimental data and mathematical models. Results obtained from numerical simulations are presented and judged with respect to the performance and stability achieved and the work needed to perform the designs. Laboratory experiments indicate partial success in the implementation of the designed control systems. Hence limited experimental results are presented to validate the performance of the control systems.