Effect of Multi-Objective Control on Ride Quality in High Speed Railway Vehicle

:The railway transportation has a significant impact on both the freight and passenger carriage, therefore it should provide a comfortable, safe, fast and inexpensive riding. In this paper, a six-degree-of-freedom half-car model for a typical high speed passenger vehicle is derived to study the ride motions of the vehicle under the random rail inputs. The random rail excitation is considered as an output of a second-order linear filter to white noise excitation and the temporal correlation between the front and the rear wheels is predicted by a second-order Pade filter. The unified “track-vehicle-human” model is formulated and an active suspension based on a Linear-Quadratic-Gaussian (LQG) control is designed to minimize the performance index which is a weighted sum of vehicle performance measures such as carbody vertical and pitch accelerations, front and rear suspension strokes, rail holding and control forces.