1. Field of the Invention
The present invention relates to a steering control system for a vehicle for carrying out steering operation using an electric motor.
2. Description of the Prior Art
Electric power-steering systems designed to assist in a driver's steering operation using an electric motor are well-known. Automatic steering systems for a vehicle are also already known from Japanese Patent Application Laid-Open Nos. 3-74256 and 4-55168, which are designed to automatically carry out reverse parking or longitudinal parking by utilizing an electric motor of a well-known power-steering system and by controlling the electric motor on the basis of the relationship between the traveling distance of the vehicle and the steering angle that are previously stored.
The known electric power-steering system has a problem in that the characteristic such as the magnitude of the assisting force of such system and the like is determined at the stage of designing of a control system, and if the characteristic is changed, it is necessary to replace the entire control system, resulting in an increased cost. The power steering system and the automatic steering system have many hardware parts commonly used in both of them. However, if the function of the automatic steering system is to be added to the electric power steering system, a control device for the electric power steering system is not used, and it is necessary to mount a control device for the electric power steering system and the automatic steering system. In this case, there is a problem that a lot of time and an increased cost are required for the development of a new control device.