Vehicle steering control device

1. A vehicle steering control device, comprising:

first turn response varying means for changing a gain of a yaw rate of a vehicle with respect to a steering operation;

second turn response varying means for changing a gain of a lateral acceleration of the vehicle with respect to the steering operation; and

control means for controlling the first turn response varying means and the second turn response varying means,

the control means being configured to control, under a state in which a magnitude of a curvature of a travel path is equal to or less than a reference value, at least one of the first turn response varying means and the second turn response varying means so that a ratio of the gain of the lateral acceleration to the gain of the yaw rate increases when a width of the travel path is small compared with when the width of the travel path is large.

2. The vehicle steering control device according to claim 1 , wherein the control means controls, under a state in which the width of the travel path changes to decrease, at least one of the first turn response varying means and the second turn response varying means based on a width of a travel path for control, which is corrected so that the width changes earlier and more slowly than the width of the actual travel path.

3. The vehicle steering control device according to claim 1 , wherein the control means controls, under a state in which the curvature of the travel path changes to increase, at least one of the first turn response varying means and the second turn response varying means based on a curvature of a travel path for control, which is corrected so that the curvature changes earlier and more slowly than the curvature of the actual travel path.

4. The vehicle steering control device according to claim 1 , wherein the control means acquires information on a yaw angle of the vehicle, and controls at least one of the first turn response varying means and the second turn response varying means so that a change in at least one of the gain of the yaw rate and the gain of the lateral acceleration caused by a change in the width of the travel path becomes slower when a magnitude of the yaw angle of the vehicle is large compared with when the magnitude of the yaw angle of the vehicle is small.

5. The vehicle steering control device according to claim 1 , wherein the first turn response varying means changes a relationship of a steered angle of a front wheel with respect to a steering operation amount.

6. The vehicle steering control device according to claim 1 , wherein the first turn response varying means changes a steering characteristic of the vehicle.

7. The vehicle steering control device according to claim 1 , wherein the second turn response varying means changes a relationship of a steered angle of a rear wheel with respect to a steered angle of a front wheel.

8. A vehicle steering control device, comprising:

first turn response varying means for changing a derivative gain of a yaw rate of a vehicle with respect to a steering operation speed;

second turn response varying means for changing a derivative gain of a lateral acceleration of the vehicle with respect to the steering operation speed; and

control means for controlling the first turn response varying means and the second turn response varying means,

the control means being configured to control, under a state in which a magnitude of a curvature of a travel path is equal to or more than a reference value, at least one of the first turn response varying means and the second turn response varying means so that a ratio of the derivative gain of the lateral acceleration to the derivative gain of the yaw rate increases when a width of the travel path is small compared with when the width of the travel path is large.

9. The vehicle steering control device according to claim 8 , wherein the control means controls, under a state in which the width of the travel path changes to decrease, at least one of the first turn response varying means and the second turn response varying means based on a width of a travel path for control, which is corrected so that the width changes earlier and more slowly than the width of the actual travel path.

10. The vehicle steering control device according to claim 8 , wherein the control means controls, under a state in which the curvature of the travel path changes to increase, at least one of the first turn response varying means and the second turn response varying means based on a curvature of a travel path for control, which is corrected so that the curvature changes earlier and more slowly than the curvature of the actual travel path.

11. The vehicle steering control device according to claim 8 , wherein the control means acquires information on a yaw angle of the vehicle, and controls at least one of the first turn response varying means and the second turn response varying means so that a change in at least one of the derivative gain of the yaw rate and the derivative gain of the lateral acceleration caused by a change in the width of the travel path becomes slower when a magnitude of the yaw angle of the vehicle is large compared with when the magnitude of the yaw angle of the vehicle is small.

12. The vehicle steering control device according to claim 8 , wherein the first turn response varying means changes a relationship of a steered angle of a front wheel with respect to a steering operation amount.

13. The vehicle steering control device according to claim 8 , wherein the first turn response varying means changes a steering characteristic of the vehicle.

14. The vehicle steering control device according to claim 8 , wherein the second turn response varying means changes a relationship of a steered angle of a rear wheel with respect to a steered angle of a front wheel.