Identification of transient characteristics of leveling valve utilizing pneumatically controllable leveling rod (Proposal of a test method and an optimization algorithm using hybrid PSO/gradient method involving narrowing-down of definition area)

Abstract

This paper proposes an identification method for transient characteristic parameters of the leveling valve, especially focusing on the leveling valve which has a dead zone of flow rate and the time delay on starting supply/exhaust operation.The transient characteristics of the leveling valve is crucial to discuss the quasi-static decrement in wheel load when a railway vehicle passes a transition curve. However, it is difficult to identify the transient characteristics through the conventional shaking test because of the time delay of operation. To identify the transient characteristics, this paper proposes a stationary test method which utilizes the "pneumatically controllable leveling rod" to acquire the step response of the leveling valve. This paper also proposes a parameter optimization method using the hybrid PSO/gradient method involving narrowing-down of the parameter definition area to solve the optimization problem for the transient characteristic parameters of the leveling valve, of which objective function contains highly nonlinear dynamics. The proposed identification method is verified through numerical experiments and real vehicle experiments.