Steering control device, steering control method, and steering support system including same

A steering control method, the method comprising:

• calculating a rack movement command value indicating a movement of a rack based on steering information according to turning of a steering wheel;
• by receiving a rack movement detection value obtained by detecting the movement of the rack when the movement of the rack is detected, calculating a difference value between the rack movement command value and the rack movement detection value;
• calculating a torque based on the difference value and two virtual linkage parameters;
• and
• controlling a motor to apply the torque, calculated based on the difference value and the two virtual linkage parameters, to the steering wheel,
• wherein the two virtual linkage parameters correspond to two characteristics of a virtual linkage between the steering wheel and the rack, which are mechanically separated,
• wherein the two virtual linkage parameters include an elastic parameter comprising a torsion parameter of a virtual torsion bar or a spring parameter of a virtual spring, and further include a damping parameter of a virtual damper,
• wherein the rack movement command value includes a rack position command value and a rack movement speed command value,
• wherein the calculating of the difference value between the rack movement command value and the rack movement detection value comprises calculating a first difference value between the rack position command value and a rack position detection value obtained by detecting an actual position of the rack, and calculating a second difference value between the rack movement speed command value and a rack movement speed detection value obtained by detecting an actual movement speed of the rack,
• wherein the calculating of the torque comprises calculating the torque by applying the elastic parameter of the torsion parameter of the virtual torsion bar or the spring parameter of the virtual spring to the first difference value between the rack position command value and the rack position detection value and applying the damping parameter of the virtual damper to the second difference value between the rack movement speed command value and the rack movement speed detection value, and
• wherein at least one of the two virtual linkage parameters is a variable mapped based on at least one of the first and second difference values.

A steering assistance system having a structure in which a steering input device and a steering output device are mechanically separated, the steering assistance system comprising:

• a steering angle sensor for detecting a steering angle according to turning of a steering wheel;
• a force-generating motor for supplying a force to the steering wheel;
• a steering motor for axially moving a rack;
• a rack position sensor for detecting a position of the rack;
• and
• a steering control device comprising an electronic controller unit configured to control the steering motor based on steering information and control the force-generating motor based on the steering information and rack position information received from the rack position sensor,
• wherein the electronic controller unit is configured to calculate a rack movement command value indicating a movement of the rack based on the steering information, calculate a difference value between the rack movement command value and a rack movement detection value received from the rack position sensor, calculate a torque based on the difference value and two virtual linkage parameters set in advance, and supply a driving current corresponding to the calculated torque to the force-generating motor,
• wherein the two virtual linkage parameters corresponds to two characteristics of a virtual linkage between the steering input device and the steering output device,
• wherein the two virtual linkage parameters include an elastic parameter comprising a torsion parameter of a virtual torsion bar or a spring parameter of a virtual spring, and further include a damping parameter of a virtual damper,
• wherein the rack movement command value includes a rack position command value and a rack movement speed command value,
• wherein the electronic controller unit is configured to calculate a first difference value between the rack position command value and a rack position detection value obtained by detecting an actual position of the rack, and calculate a second difference value between the rack movement speed command value and a rack movement speed detection value obtained by detecting an actual movement speed of the rack,
• wherein the electronic controller unit is configured to calculate the torque by applying the elastic parameter of the torsion parameter of the virtual torsion bar or the spring parameter of the virtual spring to the first difference value between the rack position command value and the rack position detection value and applying the damping parameter of the virtual damper to the second difference value between the rack movement speed command value and the rack movement speed detection value, and
• wherein of the at least one two virtual linkage parameters is a variable mapped based on at least one of the first and second difference values.