Disclosed herein are an apparatus and method of controlling a motor-driven power steering system. The apparatus may include: a sensor configured to detect at least one of a steering angle, an angular speed, and a column torque in the motor-driven power steering system; and a controller configured to determine whether a reverse steering operation has been performed based on the steering angle or the angular speed, and configured to output, when non-reverse steering, a high-frequency compensation gain (a second gain) based on the column torque, as a final compensation gain, and output, when reverse steering, a value obtained by applying an additional compensation gain (a first gain) optimized corresponding to an angular acceleration to the high-frequency compensation gain (the second gain), as the final compensation gain.

Disclosed herein are an apparatus and method of controlling a motor-driven power steering system. The apparatus may include: a sensor configured to detect at least one of a steering angle, an angular speed, and a column torque in the motor-driven power steering system; and a controller configured to determine whether a reverse steering operation has been performed based on the steering angle or the angular speed, and configured to output, when non-reverse steering, a high-frequency compensation gain (a second gain) based on the column torque, as a final compensation gain, and output, when reverse steering, a value obtained by applying an additional compensation gain (a first gain) optimized corresponding to an angular acceleration to the high-frequency compensation gain (the second gain), as the final compensation gain.

A steering apparatus of a steer-by-wire (SBW) system includes a structure for changing the frictional force of the system and a structure for limiting the rotation range of a steering wheel. The steering apparatus includes: a shaft rotatably interlocked with a steering wheel, a friction member surrounding the shaft and contacting the shaft, a frictional force provision device for narrowing and widening the friction member in the radial direction of the shaft to change the frictional force of the friction member that contacts the shaft, and a steering limitation device for regulating the rotation of the shaft using a stopper provided at the friction member during the rotation of the shaft to limit the steering of the steering wheel.

A steering apparatus of a steer-by-wire (SBW) system includes a structure for changing the frictional force of the system and a structure for limiting the rotation range of a steering wheel. The steering apparatus includes: a shaft rotatably interlocked with a steering wheel, a friction member surrounding the shaft and contacting the shaft, a frictional force provision device for narrowing and widening the friction member in the radial direction of the shaft to change the frictional force of the friction member that contacts the shaft, and a steering limitation device for regulating the rotation of the shaft using a stopper provided at the friction member during the rotation of the shaft to limit the steering of the steering wheel.

An apparatus and method of controlling a motor driven steering system may selectively perform a motor current control of the motor driven steering system for reducing motor noise according to a present motor-applied current applied to a steering motor of the motor driven steering system when it is determined from vehicle speed information or wheel speed information detected by a first sensor that a vehicle is currently in a stopped state and it is determined from steering angle information detected by a second sensor that a steering wheel is currently in a steering wheel holding state.

A control unit functionally comprises a first steering-torque application control part which commands a steering actuator of a vehicle to execute application of a steering torque determined by a first steering characteristic CH1 and a second steering-torque application control part which commands the steering actuator of the vehicle to execute application of a steering torque determined by a second steering characteristic CH2. In a case where the vehicle travels at a curved portion of the lane, the first steering characteristic CH1 is set such that a first steering-force increase part L1 is located further toward an allowed right-end point E.sub.GR as a vehicle speed becomes higher and the second steering characteristic CH2 is set such that a magnitude of a torque maintenance part L4 becomes lower as a radius of curvature of the curved portion of the lane becomes smaller, like CH2H-CH2L.

A control unit functionally comprises a first steering-torque application control part which commands a steering actuator of a vehicle to execute application of a steering torque determined by a first steering characteristic CH1 and a second steering-torque application control part which commands the steering actuator of the vehicle to execute application of a steering torque determined by a second steering characteristic CH2. In a case where the vehicle travels at a curved portion of the lane, the first steering characteristic CH1 is set such that a first steering-force increase part L1 is located further toward an allowed right-end point E.sub.GR as a vehicle speed becomes higher and the second steering characteristic CH2 is set such that a magnitude of a torque maintenance part L4 becomes lower as a radius of curvature of the curved portion of the lane becomes smaller, like CH2H-CH2L.

A computer includes a processor and a memory, the memory storing instructions executable by the processor to detect an actual steering column torque and an actual steering wheel angle, predict a steering wheel torque with a state-estimation algorithm that outputs a plurality of vehicle states including the predicted steering wheel torque, adjust the plurality of vehicle states based on an algorithm noise that is based on a steering wheel angular speed to generate estimated vehicle states, output the estimated vehicle states including an estimated user-applied steering wheel torque, and transition from an autonomous mode to a manual mode when the estimated steering wheel torque exceeds a threshold. The state-estimation algorithm accepts input including the actual steering column torque and the actual steering wheel angle and outputs the plurality of vehicle states.

A computer includes a processor and a memory, the memory storing instructions executable by the processor to detect an actual steering column torque and an actual steering wheel angle, predict a steering wheel torque with a state-estimation algorithm that outputs a plurality of vehicle states including the predicted steering wheel torque, adjust the plurality of vehicle states based on an algorithm noise that is based on a steering wheel angular speed to generate estimated vehicle states, output the estimated vehicle states including an estimated user-applied steering wheel torque, and transition from an autonomous mode to a manual mode when the estimated steering wheel torque exceeds a threshold. The state-estimation algorithm accepts input including the actual steering column torque and the actual steering wheel angle and outputs the plurality of vehicle states.

A control device for a vehicle equipped with a steering system including a steering wheel (13), a rack (12) for steering the wheels (4) of the vehicle, and a redundant arrangement for transmitting a displacement of the steering wheel to the rack, wherein upon detecting a failure in the redundant arrangement, the control device sets an upper limit speed to a first value in a first stage, and changes the upper limit speed from the first value to a second value smaller than the first value in a progressive manner in a second stage that follows the first stage.