| 摘要 |
<p>A controller of an electric power steering system for imparting assist torque to a steering mechanism by driving a motor through a current control section with a current command value operated at a torque control section, comprising a motor angle sensor for detecting a motor angle, a torque sensor for detecting steering torque applied to a steering shaft, a section for detecting the relative steering angle ?r based on the output from the motor angle sensor, a steering angle speed detecting section for determining the angular speed of the motor, and a section for judging the vehicle speed. The controller of an electric power steering system is further provided with a neutral point operating section for judging straight traveling of the vehicle based on the steering angle speed, steering torque and vehicle speed and performing operation while regarding as the neutral point the relative steering angle ?r when straight traveling sustains for a predetermined time or longer, and a section for operating an absolute steering angle from the difference between the neutral point obtained at the neutral point operating section and the relative steering angle ?r.</p> |
