A Simple Strategy for Tyre Force Distribution to Improve the Performance of a Four Wheel Independent Steer-by-wire Vehicle

摘要

In a four wheel independent steer-by-wire system, all four wheels of a vehicle are steered independently by separate actuators which respond to computer generated signals. This freedom, if judiciously used, can lead to better vehicle performance. This work proposes a method of deciding the steering angles of each wheel at different speeds in a four wheel independent steer-by-wire vehicle. This is based on obtaining the distribution of lateral forces of inner and outer tyres through a sigmoid function which depends on the ratio of cornering stiffness of outer and inner tyres. Simulations show that such a system allows considerable improvement over four wheel non-independent steering and two wheel steering systems. A 10-20% increase in speed is possible during low speed off-limit cornering and 40% increase during high speed on-limit cornering.