Frequency bandwidth extension for angular vibration table based on extremum seeking control

Aiming to improve the frequency bandwidth of angular vibration table, this paper proposes a novel bandwidth extension scheme based on extremum seeking control (ESC). In this scheme, two perturbation extremum seeking controllers are employed to adjust the phase and amplitude of the sine input signal based on the extracted envelope of tracking error as the cost function of ESC to be minimized, for the purpose of compensating phase lag and amplitude decay of the system output. Furthermore, an adaptive amplitude adjusting method is designed with nonlinear transformation to accelerate the convergence as well as eliminate the unexpected steady-state oscillation existing in system output, which is caused by the perturbation signal of ESC. Consequently, the frequency bandwidth of the closed-loop system is extended greatly with the proposed scheme, which is verified sufficiently with simulations.