Development of an electrorheological active buffer for railway vehicles—estimation of thecapacity from prototype performance

Abstract

This paper is a study on the development of an active buffer for railway vehicles usingelectrorheological (ER) fluid as a functional material. The coupler force is controlled byadjusting the electric field applied to the ER fluid. A prototype buffer, which consists of ahydraulic cylinder, an ER bypass slit valve and a PID feedback controller, is fabricated.The damping force is developed in the ER valve both through the bypass slit and atthe piston–cylinder gap. In the theoretical analysis, it is assumed that the flowof the ER fluid through the bypass slit is the Bingham plastic flow-mode flowwhile it is in the Newtonian mixed-mode flow in the piston–cylinder gap. Theforce opposed by the buffer is obtained as a function of the shaft velocity and theelectric field applied to the ER fluid. The theoretical results are compared withthe experimental results. Further, an active control test using the PID feedbackcontroller is carried out for the problem where the shaft reaction force is retainedat a constant prescribed strength while the shaft is translating at a constantvelocity. Both results show that the coupler force of the railway vehicle can becontrolled effectively by using the proposed electrorheological bypass damper.