Patent ID: 6122579
Filing Date: 2000-09-19
Classification: B62D

Abstract:
An electric power steering control for a motor vehicle, comprising:a steerable wheel;an operator handwheel;a steering gear linking the steerable wheel to the operator handwheel;an electric motor coupled to the steering gear;means for deriving an output command torque signal in response to an operator input torque applied to the handwheel;for controlling current in the electric motor in response to the output command torque signal to provide steering assist torque;means for deriving a signal indicating electric motor speed;means for differentiating the signal indicating electric motor speed;means for scheduling a gain as an increasing function of electric motor torque; andmeans for modifying the differentiated signal indicating electric motor speed in response to the gain to provide a damping correction value, the means for deriving an output command signal being additionally responsive to the damping correction value to reduce torque ripple effects in the handwheel generated by the electric motor and road generated torque disturbances introduced to the handwheel through the steerable wheel.