Railway Optimal Slip Ratio Control Using Extremum Seeking Algorithm With Adaptive Amplitude Tuning

The key technology of anti-slip control system is to identify the optimal slip ratio in individual conditions for railway applications. In this paper, an extended state observer (ESO) is proposed for the immeasurable varying adhesion coefficient. With the estimated modeling error information, the deviation is eliminated by the designed compensation control rate , which results in an accurate adhesion coefficient observation. Then an extremum seeking (ES) algorithm with adaptively tuned amplitude is proposed to calculate the optimal slip ratio under current road conditions. Compared with classical ES-based methods, the proposed method has smaller oscillations and better dynamic performance. In order to get the maximum braking force, the feedback linearization control framework is proposed for a nonlinear controller of wheel optimal slip ratio. To increase the stability and robustness of the control system, a Lyapunov function with integral form is constructed. The simulation result demonstrates the effectiveness of the proposed control method.