It is an object of the present invention to suitably estimate a state of a vehicle. A vehicle state estimation section (1200) includes: a main computation section (1210) configured to carry out linear computation with respect to a state amount related to a state of a vehicle; and a tire model computation section (1240) configured to carry out nonlinear computation with direct or indirect reference to at least part of a result of the linear computation carried out by the main computation section (1210).

A damping force control device for controlling damping forces of shock absorbers by a control device, which is configured to extract first vibration components in a first frequency range and second vibration components in a higher frequency range than the first frequency range from vertical accelerations of a sprung mass at the positions of wheels, to calculate correction coefficients which decrease as the degree of the second vibration increases with respect to the degree of the first vibration, and to control damping coefficients of the shock absorbers so as to be the products of target damping forces calculated based on the vertical accelerations of the sprung mass and the correction coefficients.

A state module selectively sets a present state to a first state in a predetermined order of states; a valve control module determines first target open and closed states for valves of a suspension system based on the present state and opens and closes the valves according to the first target open and closed states, respectively; a pump control module configured to, when the valves are in the first target open and closed states, respectively, selectively operate an electric pump of the suspension system in a first direction and pump hydraulic fluid toward the suspension system; and a diagnosis module configured to: record first and second values of pressures within the suspension system measured using pressure sensors, respectively, before and after the operation of the electric pump in the first direction, respectively; and selectively diagnose faults in a first subset of the valves based on whether pressure increases occurred.

A damping control device for a vehicle includes a control force generating device configured to generate vertical control force between a vehicle body of the vehicle and at least one wheel suspended from the vehicle body by a suspension, and an electronic control unit configured to reduce, by controlling the control force generating device to change the control force, vibration of the vehicle body that is caused by vertical vibration occurring in the wheel in response to vertical road surface displacements while the vehicle is traveling, the vertical vibration being transmitted to the vibration of the vehicle body via the suspension.

A suspension control device which controls an operation of a suspension of a vehicle includes an operation-induced state quantity estimation portion which estimates an operation-induced state quantity caused by an operation of a vehicle, a road surface-induced state quantity estimation portion which estimates a road surface-induced state quantity caused by a road surface, an operation-induced state quantity conversion portion which converts the operation-induced state quantity into an operation-induced required damping force, a road surface-induced state quantity conversion portion which converts the road surface-induced state quantity into a road surface-induced required damping force, and a current value calculation portion which determines a current value to be applied to the suspension with reference to the operation-induced required damping force and the road surface-induced required damping force.

This disclosure describes techniques for determining a state of a pressurized chamber of a suspension of a vehicle, wherein the pressurized chamber comprises a hydraulic fluid chamber and a gas chamber separated by a piston. The state is determined by varying a pressure in the hydraulic fluid chamber and determining a knee point in a change of pressure in the hydraulic fluid chamber. The knee point indicates that the separator has been bottomed out. The pressure in the knee point may be used to determine a state of the suspension system.

A method is for regulating the pressure of an air bellows belonging to an air suspension, a determination of a filling pressure generatable inside the bellows by a filling process takes place with a learning algorithm as well as via a pressure and a height measuring sensor. The pressure sensor is arranged in a feed line leading to the bellows. Before opening the valve, in successive cyclic pressure and height measurements and on the basis of a characteristic curve, in which a characteristic number as a variable representative of a bellows volume V is plotted against the bellows height, a flow rate at the bellows inlet is ascertained and an air mass flow in the line between the valve and the bellows is ascertained therefrom, integrated and added to the bellows air mass. A new filling pressure is ascertained via the algorithm.