Integrated Position and Speed Control for Rail Transit Doors Based on Speed-Current Loop

Different from typical servo systems that take position control as the first priority, rail transit door needs to reach the specified position with the established speed curve, so as to meet the safety requirements. Hence, both speed control and position control are simultaneously required, which cannot be achieved by the conventional cascaded position-speed-current loop structure. In this paper, an integrated position and speed control method for rail transit door based on speed-current loop structure is proposed. The movement of the door is divided into four stages, in which the speed mode or position mode are applied according to the instantaneous position of the door. In the last stage of position servo, in order to improve the accuracy of position control at low speed and meet the safety requirements, a method based on chopper regulator is proposed to realize servo accuracy and accident protection by adjusting the chopper current limit. Simulation and experimental results show that the proposed method is effective and easy to implement in engineering practice.