A suspension device includes: a damping device that damps a force generated between a vehicle body and a wheel of a vehicle; a determination unit that determines whether the vehicle is jumping, using an acceleration of the vehicle in a front-rear direction, an acceleration of the vehicle in a left-right direction, and an acceleration of the vehicle in a vertical direction; and a damping force control unit that increases a damping force of the damping device so as to be greater than the damping force generated when the determination unit does not determine that the vehicle is jumping, when the determination unit determines that the vehicle is jumping.

An electric suspension apparatus includes electric actuators provided for a plurality of wheels, respectively, an acceleration sensor disposed in each of the electric actuators, the acceleration sensor detecting a first acceleration, and an electric suspension control ECU controlling each of the electric actuators based on the first acceleration, and the electric suspension control ECU decreases a control amount to the electric actuator, in a case where a first speed based on the first acceleration in an up-down direction is equal to or less than a predetermined speed.

An active chassis control for a motor vehicle with an adaptive control circuit for reducing body vibrations (A.sub.actual) of the motor vehicle, in which a control unit is integrated, which, depending on a current body vibration (A.sub.actual) or a parameter correlating therewith (a), controls a chassis actuator. The control unit is followed by an adaptive unit which adapts an actuating signal (S) generated by the control unit with a driving speed-dependent scaling factor (f(v)), in particular by generating an adapted actuating signal (S′) with which the chassis actuator can be controlled. Depending on the situation, a factor allowance (Δf) can be added to the driving speed-dependent scaling factor (f(v)) in the event of a significantly greater body vibration (A.sub.o) in order to effectively dampen the significantly greater body vibration (A.sub.o).

An electric suspension apparatus includes electric actuators provided for a plurality of wheels, respectively, an acceleration sensor disposed in each of the electric actuators, the acceleration sensor detecting a first acceleration, and an electric suspension control ECU controlling each of the electric actuators based on the first acceleration, and the electric suspension control ECU decreases a control amount to the electric actuator, in a case where a first speed based on the first acceleration in an up-down direction is equal to or less than a predetermined speed.

An active chassis control for a motor vehicle with an adaptive control circuit for reducing body vibrations (A.sub.actual) of the motor vehicle, in which a control unit is integrated, which, depending on a current body vibration (A.sub.actual) or a parameter correlating therewith (a), controls a chassis actuator. The control unit is followed by an adaptive unit which adapts an actuating signal (S) generated by the control unit with a driving speed-dependent scaling factor (f(v)), in particular by generating an adapted actuating signal (S′) with which the chassis actuator can be controlled. Depending on the situation, a factor allowance (Δf) can be added to the driving speed-dependent scaling factor (f(v)) in the event of a significantly greater body vibration (A.sub.o) in order to effectively dampen the significantly greater body vibration (A.sub.o).

A suspension device includes: a damping device that damps a force generated between a vehicle body and a wheel of a vehicle; a determination unit that determines whether the vehicle is jumping, using an acceleration of the vehicle in a front-rear direction, an acceleration of the vehicle in a left-right direction, and an acceleration of the vehicle in a vertical direction; and a damping force control unit that increases a damping force of the damping device so as to be greater than the damping force generated when the determination unit does not determine that the vehicle is jumping, when the determination unit determines that the vehicle is jumping.

A signal level detection device 1 and a signal level detection method according to a means for solving a problem of the present invention varies a cut-off frequency c, of a variable low-pass filter 3 which filters a signal level r. The cut-off frequency c is varied based on the signal level r or information referred to for estimating the signal level. The signal level detection device 1 and the signal level detection method therefore reduce a delay of a rise of the obtained signal level r from an actual signal level, and sufficiently remove noise superimposed on the signal level r even when the signal level r is extremely low. Accordingly, control performance improves regardless of a degree of the signal level r.

A longitudinal acceleration calculation unit includes an LPF, an HPF, and an addition unit. The LPF acquires a longitudinal acceleration of a vehicle detected by a longitudinal acceleration sensor provided to the vehicle, and removes a high-frequency component of the acquired longitudinal acceleration. The HPF acquires a longitudinal acceleration of the vehicle estimated based on an engine torque and a brake hydraulic pressure of the vehicle, and removes a low-frequency component of the acquired longitudinal acceleration. The addition unit obtains a composed longitudinal acceleration being a longitudinal acceleration of the vehicle based on a post-high-frequency-component-removal longitudinal acceleration obtained by removing the high-frequency component by the LPF and a post-low-frequency-component-removal longitudinal acceleration obtained by removing the low-frequency component by the HPF.