Abstract: Aiming at the problem of identifying the physical parameters of railway vehicle, the state matrix of the vehicle system is obtained through state space theory and modal space theory, and then two methods of identifying the physical parameters of railway vehicles are proposed, namely, additional mass method and proportional relationship method. The additional mass method can identify all the physical parameters of the vehicle, but a specific mass needs to be added to the vehicle system. The proportional relationship method does not require additional mass, and the remaining physical parameters of the vehicle are identified on the premise that the frame quality parameter is known. The directional excitation conditions of the vehicle for physical parameter identification are designed, and the two physical parameter identification methods are verified and compared through simulation tests. The results show that adopting the additional mass method, the identification accuracy is highest when the additional mass is selected as 3% of the vehicle system. The additional mass method and the proportional relationship method have their own advantages and disadvantages in terms of identification accuracy and test implementation difficulty. Therefore, in the actual vehicle physical parameter identification, the identification method needs to be selected according to the site conditions.

Key words: railway vehicle, parameter identification, state space, modal space, physical parameter