Analysis And Optimization Of Handling And Stability Of A Roadster

The vehicle handling and stability performance consists of two parts, the ability of following the track under driver's will and the ability of keeping direction against disturbances. It is a critical factor affecting the driving safety of vehicles. Especially in the manufacture of high-speed cars, the vehicle handling and stability is the mainly criterion for vehicle performances evaluation. And how to design a car with good handling and stability performance is a key problem for all the researchers.Simulation technology is being used more and more widely in the field of engineering. With the development of multi-body dynamics, virtual prototype technology is applied to study the vehicle handling and stability performance.In this dissertation, by using virtual prototype technology and the software ADAMS/CAR, a virtual prototype of a full car was built. And suspensions were improved based on analyzing, the four different types of vehicle were built, then according to the requirement of standards, several types of test simulation such as slalom, steady state cornering test,"8"form driving test , center steering and so on, were carried on. And the results of simulations and experiments were compared. The results shows that the car which the front axes adopts double wishbone suspension and the rear axes adopts multi-link suspension is the optimum type for the car.Then the optimum type of car was optimized basing on the comprehensive evaluated function of handling and stability performance. First, the sensitivity of the coordinates of the hard points in suspensions was calculated. Based on the results of the sensitivity analysis, the coordinates of hard points were optimized respectively using ADAMS/Insight and response surface methods. After the optimization of the coordinates of hard points, the other parameters were optimized too, such as the stiffness of coil spring, the damp of damper and the coordinates of sprung-mass and so on. The analyses and comparisons of handling and stability were implemented. And then a conclusion can be draw. The optimization has improved the handling and stability performance of car to some extent. Finally, the natural frequency of the front and rear suspensions is matched.