Handing performances of vehicle with a fractional compliant rear-wheel steering system

The compliant rear-wheel steering (CRS) system can strengthen the characteristic of under-steer to guarantee the vehicle driving safety. One kind of CRS system equipped with the elasticity component of viscoelasticity is studied in this article. The kinematic simulation results show that if the steering stiffness of the CRS system is positive, the direction of compliant rear wheel steering is opposite of the front wheel. A shimmy phenomenon of rear wheel would appear in compliant system. And if the problem is serious, the vehicle even maybe out of control. On the contrary, if the steering stiffness of the CRS system is negative, the direction of rear wheel steering is as same as the front wheel. With the steering stiffness of CRS increasing, the compliant steering angle will reduce. Then the effect of CRS system for improving the vehicle handling stability is unobvious. Conversely, if the stiffness is smaller than a threshold value, the response of the CRS system would be slow. Therefore, the CRS system must be chosen with a appropriate steering stiffness, the vehicle handing performance can be improved effectively. In this case, the fractional viscoelasticity may also have a significant effect on handing performance. Further, when the elastic component is made of the intelligent material, the stability of the vehicle can be controlled by regulation of the compliant steering stiffness.