Fixed-order data-driven H_∞ controller synthesis for flexible mechanical systems: Two-stage approach

In this paper, a two-stage method is introduced to design fixed-order data-driven (Formula presented.) controller for flexible mechanical systems. In the first stage of the proposed method, unknown parameters of anti-resonance filter that is added to the forward path of the control loop of the system to minimize resonant peaks, are calculated using frequency domain data obtained from open-loop system identification tests. In the second stage, a fixed-order data-driven (Formula presented.) controller is calculated by solving an optimization problem under convex (Formula presented.) constraints obtained based on the Nyquist diagram. With the proposed method, lower order controllers that meets the performance constraints of classical model-based (Formula presented.) problems can be synthesized without need of a parametric plant model. The method developed in this study is tested experimentally on a military stabilized platform and its performance is compared with a model-based (Formula presented.) controller design method.