Damping force control apparatus for suspension

A damper, comprising:

• a cylinder configured to be attached to a support portion of a vehicle body with a buffer member interposed between the support portion and the cylinder;
• and
• a damping force control apparatus configured to set a damping force of the cylinder based on a damping force control value and to control the damping force control value, wherein
• the damping force control apparatus estimates relative displacement of a vehicle wheel with respect to the vehicle body and a relative speed of the vehicle wheel with respect to the vehicle body as estimated relative displacement and an estimated relative speed;
• the damping force control apparatus determines the damping force control value so as to suppress vibration of the vehicle body based on state variables provided from the vehicle body and the estimated relative speed;
• and
• the damping force control apparatus estimates the estimated relative speed and the estimated relative displacement based on the state variables, the determined damping force control value, and the estimated relative speed and the estimated relative displacement.

A method of controlling a suspension having a damper whose damping force is set based on a damping force, the damper being attached to a support portion with a buffer member interposed between the support portion of a vehicle body and a cylinder of the damper, the method comprising:

• estimating relative displacement of a vehicle wheel with respect to a vehicle body and a relative speed of the vehicle wheel with respect to the vehicle body as estimated relative displacement and an estimated relative speed;
• determining a damping force control value so as to suppress vibration of the vehicle body based on state variables provided from the vehicle body and the estimated relative speed;
• estimating the estimated relative speed and the estimated relative displacement based on the state variables, the determined damping force control value, and the estimated relative speed and the estimated relative displacement;
• and
• controlling the damper of the suspension based on the damping force control value.