Steering control device, steering control method, and steering support system including same
Disclosed are a steering control device, a steering control method, and a steering support system including same. Particularly, a steering control device according to the disclosure comprises: a command value calculator for calculating, on the basis of steering information corresponding to the rotation of a steering wheel, a rack movement command value that commands the movement of a rack; a difference value calculator for calculating the difference value between the rack movement command value and the rack movement sensing value by receiving a rack movement sensing value corresponding to the movement of the rack when the movement of the rack is sensed; and a reaction torque calculator for calculating reaction torque on the basis of the difference value and one or more preset virtual linkage parameters.
1 . A steering control device included in a steering assistance system comprising an electronic controller unit configured to:
calculate a rack movement command value indicating a movement of a rack based on steering information according to turning of a steering wheel;
receive a rack movement detection value obtained by detecting the movement of the rack when the movement of the rack is detected, and calculate a difference value between the rack movement command value and the rack movement detection value;
calculate a torque based on the difference value and two virtual linkage parameters; and
control 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 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, and
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 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.
2 . The vehicle control device according to claim 1 , wherein the rack movement command value includes the rack position command value indicating a position of the rack, and
wherein the electronic controller unit is configured to receive the rack position detection value obtained by detecting the actual position of the rack, and calculate the first difference value between the rack position command value and the rack position detection value.
3 . The vehicle control device according to claim 1 ,
wherein the electronic controller unit is configured to receive the rack movement speed detection value obtained by detecting the actual movement speed of the rack, and calculate the second difference value between the rack movement speed command value and the rack movement speed detection value.
4 . The vehicle control device according to claim 1 ,
wherein the electronic controller unit is configured to calculate the torque by adding a value obtained by multiplying the first difference value by the elastic parameter and a value obtained by multiplying the second difference value by the damping parameter.
5 . The vehicle control device according to claim 1 , wherein the electronic controller unit is configured to calculate the torque by multiplying each of the first and second difference values by one of the virtual linkage parameters, and
wherein the torque increases as the first or second difference value increases, and when the torque reaches a maximum torque set in advance, the torque remains at a same value as the maximum torque even when the first or second difference value increases.
6 . The vehicle control device according to claim 1 , wherein the electronic controller unit is configured to calculate a first gain based on the steering information, and calculate the counter torque by applying the first gain to a value obtained by applying one of the two virtual linkage parameters to the first or second difference value.
7 . The vehicle control device according to claim 6 , wherein the steering information includes a driver torque generated by the turning of the steering wheel by a driver, and
wherein the first gain increases or decreases as a value of the driver torque increases, or is constant independent of the value of the driver torque.
8 . The vehicle control device according to claim 6 , wherein the steering information includes a driver torque generated by the turning of the steering wheel by a driver, and wherein when a value of the driver torque is smaller than or equal to a preset threshold value, the first gain is constant independent of the value of the driver torque, and when the value of the driver torque is greater than the preset threshold value, the first gain increases or decreases as the value of the driver torque increases.
9 . The vehicle control device according to claim 1 , wherein the electronic controller unit is configured to further receive traveling information of a vehicle, calculate a second gain based on the traveling information, and calculate the torque by applying the second gain to a value obtained by applying one of the two virtual linkage parameters to the first or second difference value.
10 . The vehicle control device according to claim 9 , wherein the traveling information includes a traveling speed of the vehicle, and
wherein the second gain increases as a value of the traveling speed increases, or is constant independent of the value of the traveling speed.
11 . The vehicle control device according to claim 9 , wherein the traveling information includes traveling speed information of the vehicle, and
wherein when a value of the traveling speed is smaller than or equal to a preset threshold value, the second gain is constant independent of the value of the traveling speed, and when the value of the traveling speed is greater than the preset threshold value, the second gain increases as the value of the traveling speed increases.
12 . 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.
13 . 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.
14 . The steering assistance system according to claim 13 , further comprising a driver-supplying-torque sensor for detecting a driver torque generated by the turning of the steering wheel,
wherein the steering control device calculates a first gain based on the driver torque, and calculates the counter torque by applying the first gain to a value obtained by applying at least one of the two virtual linkage parameters to the first or second difference value.
15 . The steering assistance system according to claim 13 , further comprising a vehicle speed sensor for detecting a traveling speed of a vehicle,
wherein the counter torque calculator calculates a second gain based on the traveling speed, and calculates the torque by applying the second gain to a value obtained by applying at least one of the two virtual linkage parameters to the first or second difference value.