Research On Handling Stability Of Multi-Axle Steering Vehicle Based On Virtual Technology

Heavy vehicle has three axles at least. For its long body and large tonnage, its turning radius is very big when turns at low speed and it is inclined to lose direction control when turns at high speed. To study the multi-axle steering technology can solve this problem effectively and improve vehicle handling stability. The research usually builds the mathematic model firstly, then makes simulation and gives the handling stability evaluation in the way of datas and curves. This method has shortcomings. The mathematic model is simplified too much to reflect the real motion of vehicle which has significant influence on the validity of simulation results.To resolve the above problem, this thesis takes a three axle vehicle with all wheels steering (6WS) for example and researches on the handling stability of multi-axle steering vehicle. The specific studies are listed as follows:(1) To reflect the real dynamic characteristics of vehicle, a virtual prototype model of6WS was established in ADAMS/Car using virtual prototyping technology. The dynamically steering of middle and rear wheels was realized by increasing a rack-and-pinion steering mechanism on middle and rear axle in steering subsystem and adding a steering pivot on corresponding axle in middle and rear suspension subsystem. Steer angle and direction of middle and rear wheels was up to the steering control strategy of vehicle. Using this method to build the vehicle modle makes it easier to realize the multi-axle steering technology.(2) Based on proportional control strategy of zero mass-center side slip angle, handling stability tests for6WS and front wheels steering vehicle (2WS) were carried out and results were analyzed. The simulation result shows that6WS has better transient response characteristic, which improves vehicle mobility at low speed and handling stability at high speed.(3) Evaluation of vehicle handling stability today is mainly obtained by analyzing experiments data and curves, which is abstract and fails to describe test people’s feeling together with the specific vehicle motion. To solve the above problem, this paper developed a vehicle handling stability virtual experiment exhibition system using Delta3D and Visual Studio2008. Change of vehicle motion and surrounding scenes during the experiment can be reproduced visually with this system.(4) The correctness of result of vehicle handling stability virtual experiment must be tested by real road experiment. However, experiment data, curves and report are obtained manually in real road experiment, which is time-consuming and expensive. To solve this problem, this paper developed the vehicle handling stability experiment analysis software using Visual Studio2008and Component Works, which can collect experiment data, plot curves and create report automatically.