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In this paper, a novel sliding mode extremum seeking control (SMESC) scheme is proposed to improve the performance of the classic SMESC. In this scheme, the twisting sliding mode is employed to all...

Aiming to increase the convergence speed of perturbation based extremum seeking control, this paper proposed a novel gradient-based perturbation extremum seeking control (GPESC) scheme by combining sine perturbation signal and input-output gradient. In this scheme, the demodulated output signal in classic extremum seeking control (CESC) is replaced with filtered input-output gradient signal to decrease the fluctuation of convergence, which can speed up the movement toward extremum dramatically. Strict stability analysis of GPESC is presented by using averaging method, and parameter selection principles are discussed. Moreover the effectiveness and superiority of the proposed scheme are verified with simulations.

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.