US 12,454,310 B2
Steering device and steering method
Amane Yajima, Kanagawa-ken (JP); Yoshio Kudo, Machida (JP); Koji Anraku, Okazaki (JP); Isao Namikawa, Okazaki (JP); and Kenji Yoshida, Nagoya (JP)
Assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP); and JTEKT CORPORATION, Kariya (JP)
Filed by TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP); and JTEKT CORPORATION, Kariya (JP)
Filed on Mar. 15, 2022, as Appl. No. 17/695,017.
Claims priority of application No. 2021-069213 (JP), filed on Apr. 15, 2021.
Prior Publication US 2022/0332364 A1, Oct. 20, 2022
Int. Cl. B62D 6/00 (2006.01); B62D 5/00 (2006.01)
CPC B62D 6/00 (2013.01) [B62D 5/006 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A steering device of a steer-by-wire type, comprising:
a steering wheel mechanically separated from a turning wheel;
a reaction force actuator configured to apply a steering reaction torque to the steering wheel; and
an electronic control unit configured to control the reaction force actuator and execute a reaction torque calculation process to calculate a target reaction torque which is a target value of the steering reaction torque, wherein in the reaction torque calculation process, the electronic control unit is configured to:
obtain a value of a vehicle speed signal and a previous value of the vehicle speed signal from a vehicle speed sensor;
determine that an abnormality condition is met or not met, the abnormality condition being that an amount of change in the value of the vehicle speed signal from the previous value of the vehicle speed signal exceeds a preset threshold value, or communication between the vehicle speed sensor and the electronic control unit is interrupted;
in response to the abnormality condition being met:
execute at least one of:
a first abnormal-time process to hold a vehicle speed signal value immediately before the abnormality condition starts; or
a second abnormal-time process to hold, for calculation of a normal-time distribution ratio, the vehicle speed signal value immediately before the abnormality condition starts or hold a value of the normal-time distribution ratio immediately before the abnormality condition starts, and then change a final distribution ratio to an abnormal-time distribution ratio; and
calculate, based on the final distribution ratio, a distributed axial force obtained by distributing an angle axial force and an electric current axial force, wherein the final distribution ratio is the abnormal-time distribution ratio where a distribution ratio of the electric current axial force is 100%; and
in response to the abnormality condition not being met: calculate, based on the final distribution ratio, a distributed axial force obtained by distributing the angle axial force and the electric current axial force, wherein the final distribution ratio is the normal-time distribution ratio based on the vehicle speed signal;
calculate the target reaction torque based on the distributed axial force; and
control the reaction force actuator to apply the steering reaction torque based on the target reaction torque.