Strategy for Transfer Elemental Designing, Employing Physical Characteristic Modeling of Steering Maneuver. (Third Report: Evaluation Method for Transfer Characteristics Using Steer by Wire System)

Improvement of Electric Power Steering (EPS) system is carried out based on integrated simulation of maneuverability of steering system and vehicle dynamics. EPS development in the case of a conventional vehicle's construction is thought to be difficult because the EPS system characteristics are not easy to change to a wide extent owing to system architecture restrictions. This paper describes the advantages of steer-by-wire system in improving EPS system characteristics by giving intended maneuverability to the vehicle. Contrary to the conventional method, the intended steering characteristics can be easily set without serious restrictions caused by vehicle construction. Emulation of the characteristics is also not difficult. Test results using an actual steer-by-wire vehicle show that the optimum steering characteristics to improve the steering maneuverability is realized as time-delay constant τ =25 - 50ms of steering transient response.