Design Concept and Advantages of Steer-by-Wire System 2008-01-0493

Because of recent advances in steering control technology, steer-by-wire systems have continued to become more realistic. The principal issue for these steer-by-wire systems is considered to be promoting reliability through the construction of a design concept that can be utilized appropriately by drivers. This paper first describes the flow between the concept and system structure, and proposes a steer-by-wire system with a mechanical backup mechanism as one possibility. This paper also describes an investigation into its potential advantages using an experimental vehicle installed with the proposed system structure. The potential advantages of steer-by-wire are improved vehicle driving performance, vehicle maneuverability, and the feasibility of innovative packaging and design. In order to make improved maneuverability and design innovations compatible, it is critical to achieve steering characteristics that require little maneuvering angle. Here, a steer-by wire system has been developed with small steering angle characteristic (quick gear ratio steering characteristic) that is easy to maneuver. Based on the frequency of steering wheel corrections required by the driver, evaluations of the developed characteristics show that the maneuverability of the proposed system is improved over a system that has simple small steering angle characteristics. Simple characteristics refer to a gear ratio that is linear and does not include any integrated logic.