Ride Comfort Research And Optimization Of Off-road Vehicle Base On Deformation Terrain By Using GA

With the development of technology and improvement of people's living standards,car was no longer a tool to exercise the original function simply. People get higher requirements for riding comfort and security of driving. It requires sevral aspects should be considered more completely in the design of the cars. For the off-road vehicles, people not only have requirements for their driving performance in its general pavement, but also have more consideration to the driving performance on deformation terrain.Based on the off-road vehicle, the paper was discussed several methods of the tires interaction with the deformation road. Then the anti-stress formula of the tires interact with the deformation road was deduced. By using the ADAMS's interface of TIRSUB and REQSUB User Written Subroutine to write the dynamic database into DLL files in FORTRAN languag, a national standard two-dimensional space of random irregularities were built based on the harmonic superposition theory.The necessary parameters of the virtual prototype model of the off-road vehicles in this article were obtained according to three-dimensional drawing software and the provided drawing, and the virtual prototype model of off-road vehicles had built by using ADAMS/View. Combined with the user subroutine, the model of the vehicle interaction with the deformation road was established. The model simulated on the deformation road for the ride comfort study which based on the national criterion of Method of pulse input running test-Automobile ride comfort. The simulation results showed that the body acceleration,suspension dynamic deformation and tire dynamic load of the vehicle all changed and the displacement of body increased obviously as terrain deformation amplified. The suspension adapted to the hard ground was not necessarily adapted to the soft road. Analysis of the test data indicated that the ride comfort of the vehicl should be improved further more.By analyzing the impact of suspension parameters to the response and using numerical fitting method, an approximate non-linear damper model of vibration absorbe was obtained in ADAMS/view. The forward and rear suspension stiffness and damping coefficient of linear and nonlinear were chose as the design variables, and its'range was confirmed by the design of certain experiment method and constanint fuctions. After simulated on the different road like hard road,medium hard road,soft road, very softer road by using Genetic algorithm, the optimal suspension stiffness and damping of the model were obtained. Then the optimized model which simulated on the four kinds of road surface was used to improve the overall performance of suspension. The results indicated that the ride comfort of the optimized off-road vehicle was improved on the all of the road and provided a theoretical reference for the design of the off-road vehicle suspension in the future.