Abstract: An electric power steering device wherein mechanical friction is electrically provided. A steering torque value is detected by a steering torque sensor according to the operation of a steering wheel. An assist current value is calculated by an assist control section on the basis of the steering torque value. A target current value based on the assist current value is determined. For providing friction to the operation of the steering wheel, a friction control section and a friction torque value/current value conversion section generate a corrected steering torque value. A second corrected target current value is created by correcting a first corrected target current value by a friction current value. The corrected steering torque value is obtained by correcting the steering torque value by a friction torque value. The target current value is generated, resulting in a motor being subjected to driving control.

Abstract: The present invention discloses a controller of an electric power-assist steering system including a torque detector for detecting a torque applied with a steering wheel that steers a steering system; a steering status determining section for determining a steering status of either “turn” or “return” of a steering wheel; and a motor controlling unit for driving a motor in accordance with a target current value calculated based on at least a torque value from the torque detector and the steering status of either “turn” or “return” of the steering wheel from the steering status determining section, wherein the motor controlling unit sets a target current value right after a time when the steering status is switched between “turn” and “return” to be substantially equal to an actual current value right before a time when the steering status is switched between “turn” and “return”.

Abstract: An electric power steering device wherein mechanical friction is electrically provided. A steering torque value is detected by a steering torque sensor according to the operation of a steering wheel. An assist current value is calculated by an assist control section on the basis of the steering torque value. A target current value based on the assist current value is determined. For providing friction to the operation of the steering wheel, a friction control section and a friction torque value/current value conversion section generate a corrected steering torque value. A second corrected target current value is created by correcting a first corrected target current value by a friction current value. The corrected steering torque value is obtained by correcting the steering torque value by a friction torque value. The target current value is generated, resulting in a motor being subjected to driving control.

Abstract: An electric steering system includes a steering torque measuring device for measuring a steering torque input into a steering system, a steering speed measuring device for measuring a steering speed of the steering system; a target current computing section for computing a target current based on the steering torque measured by the steering torque measuring device, and a control section for applying a steering power to the steering system by driving a motor according to the target current.

Abstract: An electric steering system includes a steering torque measuring device for measuring a steering torque input into a steering system, a steering speed measuring device for measuring a steering speed of the steering system; a target current computing section for computing a target current based on the steering torque measured by the steering torque measuring device, and a control section for applying a steering power to the steering system by driving a motor according to the target current.

Abstract: An electric steering system includes a device for measuring a steering input into a steering system; a device for measuring a steering speed; a section for computing a target current based on the steering input; and a control section for applying a steering power to the steering system by driving a motor according to the target current, and applying damping to the steering system based on the steering speed. A rate of increase in a damper gain defined when the steering speed is equal to or greater than a predetermined value is higher than that defined when the steering speed is less than the predetermined value, or the damper gain defined when the steering speed is equal to or greater than a predetermined value has a constant value increased in a step form from values of the damper gain defined when the steering speed is less than the predetermined value.

Abstract: The present invention discloses a controller of an electric power-assist steering system including a torque detector for detecting a torque applied with a steering wheel that steers a steering system; a steering status determining section for determining a steering status of either “turn” or “return” of a steering wheel; and a motor controlling unit for driving a motor n accordance with a target current value calculated based on at least a torque value from the torque detector and the steering status of either “turn” or “return” of the steering wheel from the steering status determining section, wherein the motor controlling unit sets a target current value right after a time when the steering status is switched between “turn” and “return” to be substantially equal to an actual current value right before a time when the steering status is switched between “turn” and “return”.

Abstract: An electric steering system includes a device for measuring a steering input into a steering system; a device for measuring a steering speed; a section for computing a target current based on the steering input; and a control section for applying a steering power to the steering system by driving a motor according to the target current, and applying damping to the steering system based on the steering speed. A rate of increase in a damper gain defined when the steering speed is equal to or greater than a predetermined value is higher than that defined when the steering speed is less than the predetermined value, or the damper gain defined when the steering speed is equal to or greater than a predetermined value has a constant value increased in a step form from values of the damper gain defined when the steering speed is less than the predetermined value.

Abstract: In a steering control system for controlling torque steer in a vehicle equipped with an electric power steering device and a torque split arrangement for individually controlling traction and/or braking force of right and left wheels, a difference in traction and/or braking force between the right and left wheels which may be produced by the torque split arrangement may give rise to torque steer depending on the geometry of the wheel suspension system of the vehicle. The control unit for the electric power steering device additionally receives an additional signal for providing an additional steering torque which is required for canceling the torque steer. Thus, the torque steer can be eliminated both economically and reliably without requiring to modify the wheel suspension system.

Abstract: In a steering system which produces a reactive steering assist torque which tends to cancel any unintended or undesired behavior of the vehicle, the control unit for the steering system is prevented from producing any reactive steering assist torque when the vehicle speed is zero so that no reactive steering assist torque may be produced to the discomfort of the vehicle even when the vehicle is being moved by external causes such as when being turned by a turntable or being transported by a car lift or a car carrier.

Abstract: In a steering system which produces a reactive steering assist torque which tends to cancel any unintended or undesired behavior of the vehicle, the relationship between the steering angle and the vehicle behavior such as the yaw rate and the lateral acceleration reverses in sense depending on the traveling direction of the vehicle. To prevent the control unit for the steering system from producing any reactive steering assist torque which could worsen the behavior of the vehicle when the vehicle is traveling rearward, the control unit either eliminates or reverses the sense of the reactive steering assist torque when the vehicle is traveling rearward.