Experimental verification using a driving simulator of the effect of simultaneous optimal distribution of tyre forces for active vehicle handling control

Abstract

Both theoretical and experimental studies are carried out in order to prove the effect of the simultaneous optimum distribution of lateral and longitudinal tyre forces on enhancement of vehicle handling and stability assuming that all four wheels can be independently steered and driven/braked. A driving simulator is used as an experimental instrument to investigate the effect of the optimum tyre force distribution control. The inputs to the optimization process are the driver's commands (steering wheel angle and foot brake pressure/accelerator pedal pressure), while the outputs are lateral and longitudinal forces on all four wheels. Lateral and longitudinal tyre forces cannot be chosen arbitrarily, but must satisfy certain specified equality constraints. The equality constraints are related to the required total longitudinal force, total lateral force and total yaw moment to achieve a given vehicle motion. The total lateral force and total moment required are introduced using the model responses of side-slip angle and yaw rate to the driver's steering input, while the total longitudinal force is computed according to the driver's command (traction/braking). The results of either computer simulation or a driving simulator show that the influence of the proposed optimum tyre force distribution control on vehicle performance enhancement is significantly apparent. Furthermore, driving simulator results show very good agreement with the computer simulation results presented.