High-frequency perturbation in hill-climbing systems

A method for improving the noise performance of parameter-perturbation optimising systems is described. In this method, a periodic perturbation of frequency close to the natural frequency of the system is used, and adjustments to the parameter are made every m perturbation cycles, where m is typically between 10 and 100. Analysis shows that a higher optimising-loop gain and increased reliability in transient response and steady-state accuracy can be obtained using this technique. Limitations of the technique are discussed. The application of the method to multiparameter optimising systems is investigated, and it is shown that the undesirable crosscoupling effects previously observed are greatly reduced. Experimental results are in good agreement with theoretical predictions.