Summary
In experimental nonlinear modal analysis, phase-locked loops with usually heuristically determined controller parameters are used. In this work, approaches to systematically design the control parameters are presented. Three variations of the method with different levels of complexity were developed. While the most simple one relies on severe simplifications, e. g. linear behavior of the structure under test, the most advanced one accounts for the nonlinearity of the system and makes it possible to select amplitudedependent controller parameters. While all methods lead to a stable and robust control loop, the more advanced variants promise significantly shorter settling times of the controller and thus shorter test times.
