Patent ID: 11964713
Assignee: NSK LTD.
Field: Transport (Mechanical engineering)
Classification: CPC B | IPC B

Claim 3:
4. A vehicle steering device comprising:
a reaction force device configured to apply steering reaction force to a wheel;
a drive device configured to turn tires in accordance with steering of the wheel; and
a control unit configured to control the reaction force device and the drive device, wherein
the control unit comprises:
a target steering torque generation unit configured to generate target steering torque as a target value of steering torque; and
an end target steering torque generation unit configured to generate, based on the steering angle of the wheel and an end steering angle corresponding to a maximum turning angle, a first torque signal that is zero in a region in which the absolute value of the steering angle of the wheel is smaller than the end steering angle and that increases from zero at a predetermined change rate in a region in which the absolute value of the steering angle is equal to or larger than the end steering angle, and
the target steering torque generation unit generates a second torque signal based on a predetermined basic map in accordance with at least the vehicle speed of a vehicle and the steering angle and generates the target steering torque by adding the first torque signal to the second torque signal, wherein
the end target steering torque generation unit generates the first torque signal by using Expression (1) below when Tref_e represents the first torque signal, θh represents the steering angle, θh_e represents the end steering angle, and Ke represents a coefficient that determines the gradient of the first torque signal in the region in which the absolute value of the steering angle is equal to or larger than the end steering angle,

Tref_e=Ke×max(0,(|θh|−θh_e))×sign(θh)   (1).