Steering system and steering control apparatus

1. A steering system comprising:

a steering member provided in a vehicle and configured to be rotated;

an adjustment apparatus configured to adjust a rotary direction vibration of the steering member; and

a steering control apparatus configured to control the adjustment apparatus, in accordance with at least one operating condition of the vehicle, so as to adjust the rotary direction vibration, wherein

the adjustment apparatus is configured to adjust a degree by which the rotary direction vibration is transmitted to the steering member,

the adjustment apparatus is configured to adjust the rotary direction vibration by outputting an assist steering force for supplementing a steering force input into the steering member by the driver,

the steering control apparatus is configured to switch between a plurality of filter characteristics of a filter used to calculate the assist steering force, in accordance with the operating condition of the vehicle, the plurality of the filter characteristics having different degrees with which a signal corresponding to the rotary direction vibration is likely to be passed through the filter such that a magnitude of the signal passed through the filter at any given frequency is different for each of the plurality of filter characteristics,

the at least one operating condition includes at least one of a speed of the vehicle or an absolute value of an acceleration acting on the vehicle,

the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration when the speed of the vehicle is relatively high, relative to the rotary direction vibration when the speed is relatively low, and

the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration when the absolute value of an acceleration acting on the vehicle is relatively large, relative to the rotary direction vibration when the absolute value of the acceleration is relatively small.

2. The steering system according to claim 1 , wherein

the at least one operating condition further includes a torque acting on the steering member, and

the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration when the torque acting on the steering member is relatively large, relative to the rotary direction vibration when the torque is relatively small.

3. The steering system according to claim 1 , wherein

the at least one operating condition further includes a steering angle of the steering member, and

the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration when the steering angle of the steering member is relatively large, relative to the rotary direction vibration when the steering angle is relatively small.

4. The steering system according to claim 1 , wherein

the at least one operating condition further includes a steering angle velocity of the steering member, and

the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration when the steering angle velocity of the steering member is relatively large, relative to the rotary direction vibration when the steering angle velocity is relatively small.

5. The steering system according to claim 1 , wherein the steering control apparatus controls the adjustment apparatus to vary a magnitude of the rotary direction vibration in accordance with a driving tendency in driving the vehicle.

6. The steering system according to claim 5 , wherein the steering control apparatus determines the driving tendency on the basis of an operating mode selected in another apparatus having a plurality of operating modes.

7. The steering system according to claim 1 , wherein the at least one operating condition of the vehicle further includes at least one of a torque acting on the steering member, a steering angle of the steering member, a steering angle velocity of the steering member, and a driving tendency in driving the vehicle.

8. The steering system according to claim 1 , wherein the steering control apparatus is configured to control the adjustment apparatus in accordance with a selection operation performed by a user.

9. The steering system according to claim 1 , wherein:

the steering control apparatus is configured to obtain a steering angle velocity, to compare the steering angle velocity obtained with a preset predetermined value to determine whether or not the steering angle velocity is larger than the predetermined value, and

when the steering control apparatus determines that the steering angle velocity is larger than the predetermined value, the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration, relative to the rotary direction vibration when the steering angle velocity is equal to or smaller than the predetermined value.

10. The steering system according to claim 1 , wherein the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration when the speed of the vehicle is greater than a predetermined value.

11. A steering system comprising:

a steering member provided in a vehicle and configured to be rotated;

an adjustment apparatus configured to adjust a rotary direction vibration of the steering member, the adjustment apparatus being configured to adjust a degree by which the rotary direction vibration is transmitted to the steering member; and

a control apparatus configured to control the adjustment apparatus, in accordance with a selection operation performed by a user, so as to adjust the rotary direction vibration, wherein

the adjustment apparatus is configured to adjust the rotary direction vibration by outputting an assist steering force for supplementing a steering force input into the steering member by the driver,

the control apparatus is configured to switch between a plurality of filter characteristics of a filter used to calculate the assist steering force, in accordance with at least one operating condition of the vehicle, the plurality of the filter characteristics having different degrees with which a signal corresponding to the rotary direction vibration is likely to be passed through the filter such that a magnitude of the signal passed through the filter at any given frequency is different for each of the plurality of filter characteristics,

the at least one operating condition includes at least one of a speed of the vehicle or an absolute value of an acceleration acting on the vehicle,

the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration when the speed of the vehicle is relatively high, relative to the rotary direction vibration when the speed is relatively low, and

the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration when the absolute value of an acceleration acting on the vehicle is relatively large, relative to the rotary direction vibration when the absolute value of the acceleration is relatively small.

12. A steering control apparatus comprising:

a control unit configured to control an adjustment apparatus, in accordance with at least one operating condition of a vehicle, so as to adjust a rotary direction vibration of a steering member, the adjustment apparatus being configured to adjust a degree by which the rotary direction vibration is transmitted to the steering member, wherein

the adjustment apparatus is configured to adjust the rotary direction vibration by outputting an assist steering force for supplementing a steering force input into the steering member by the driver,

the control unit is configured to switch between a plurality of filter characteristics of a filter used to calculate the assist steering force, in accordance with the at least one operating condition of the vehicle, the plurality of the filter characteristics having different degrees with which a signal corresponding to the rotary direction vibration is likely to be passed through the filter such that a magnitude of the signal passed through the filter at any given frequency is different for each of the plurality of filter characteristics,

the at least one operating condition includes at least one of a speed of the vehicle or an absolute value of an acceleration acting on the vehicle,

the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration when the speed of the vehicle is relatively high, relative to the rotary direction vibration when the speed is relatively low, and

the steering control apparatus controls the adjustment apparatus to increase the rotary direction vibration when the absolute value of an acceleration acting on the vehicle is relatively large, relative to the rotary direction vibration when the absolute value of the acceleration is relatively small.