Modelling and simulation of driving dynamics of wheeled launch system under random road surface excitation

Modelling and simulation of driving dynamics is the prerequisite and basis for the dynamics performance and test design of the wheeled launch system (WLS). With the improvement of dynamics performances of the WLS, a fast and efficient dynamics computational method for large-scale multibody systems is urgently needed. This research proposes a dynamics model to investigate the characteristics of the WLS using the transfer matrix method for multibody systems, and the corresponding topology and dynamics equations are established. Based on the inverse fast Fourier transform (IFFT) method, the mathematical model of road roughness for parallel wheels is reconstructed. Combined with the Monte Carlo method, the dynamic characteristics of WLS under random road surface excitation are simulated and discussed. The analysis results indicate that as road roughness grade and driving speed increase, the vibration amplitude of acceleration of the WLS becomes larger. Within the normal speed, the influence of road excitation on the vehicle body is much greater than vehicle speed. Modal test and driving test validate the correctness of dynamics modelling and simulation. This study can be expanded to other multibody systems that contain probabilistic uncertainties for dynamics modelling and analysis.