A Feed-forward Featured Cascade PI Control Strategy for Tram Active Steering

Active steering is a technique that allows a railway vehicle to steer itself by adjusting the angle of a wheelset in order to avoid contact between flange and rail. This can improve wear, ride comfort, safety, and energy efficiency. This article examines the control requirements for a tram vehicle navigating curves with radii as small as 20 meters. An analysis of the angle that an actively steered axle has to maintain reveals that entering and leaving a curve represent a quadratic disturbance to the angle. To deal with this disturbance, a cascade PI controller is proposed. The controller consists of two loops: an inner loop that controls the wheel angle and an outer loop that controls the lateral deviation of the tram. The controller parameters are designed using a linearized model of the tram and are validated by simulations. The results show that the cascade PI controller can effectively reduce the quadratic disturbance and improve the lateral performance of the tram in curves. Copyright (C) 2024 The Authors. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)