Abstract: Based on the vehicle-track coupled dynamics, the vehicle-track coupled model for a road-rail fire fighting vehicle traveling on the track was established and compared with the traditional railway vehicle model. For the validation of the two models, field experiments were made. The comparisons between the experimental test results and numeral simulation results indicate that the vehicle-track coupled model is better in accordance with the reality than the traditional railway vehicle model. Based on the vehicle-track model, the unified objective function method was used for the optimization of suspension parameters. The optimization results indicate that root-mean-square values of car body acceleration and wheel-rail force are reduced by 22.22% and 18.63%, respectively. So the method can improve riding quality and decrease wheel-rail dynamic interaction.

Key words: road-rail fire fighting vehicle, vehicle-track coupled dynamics, parameter optimization；penalty function method