Research on ATO Control Algorithm for Urban Rail Trains Considering Conversion Characteristics of Train Operating Conditions

Precise control of the train along the target speed curve is one of the goals of the development of urban rail transit automatic operation system. Overshoot caused by the train's working condition conversion characteristics during the actual operation of the train is an urgent need to be solved by the current train automatic operation controller as excessive overshoot will trigger emergency braking of the train. In this paper, a rigid multi-mass point model was established and the kinematic equation was constructed to describe the changing basic resistance and the additional resistance of the ramp and curve. Secondly, the characteristics of the train when changing among train operating conditions were analyzed, and the cruising operating condition of the train was decomposed into the combination of traction, coasting and braking conditions. The transmission response model of the train command acceleration and the motion model of the train in the coasting condition were given, and the conversion process between traction and braking conditions is modeled by combining these two models. Then, an early switching algorithm combined with the conventional PID controller and the sliding mode PID controller is proposed and the specific steps of the early switching algorithm for both controllers are elaborated. Finally, by simulating a specific subway line in China, it is concluded that the early switching algorithm can suppress the overshoot of the original controller without affecting arrival punctuality and stopping accuracy when the train condition is switched.