An apparatus of controlling damping force through road frequency classification may include high pass filters configured to perform high-pass filtering of detecting values of wheel vibration input from wheel vibration sensors according to different cutoff frequencies, a main frequency extraction module configured to determine a main frequency of the wheel vibration based on filtered values output from the high pass filters, a maximum amplitude and amplitude ratio extraction module configured to determine a maximum amplitude and an amplitude ratio of the wheel vibration based on the filtered values, a road gripping force control determination module configured to determine whether or not road gripping force is to be controlled based on the determined main frequency and the determined maximum amplitude and amplitude ratio, and a damper control module configured to determine the damping force of dampers of a vehicle based on results of determination and road roughness.

A suspension characteristic is changed depending on a travel state by a simple structure. An ECU uses a vehicle speed-spring constant setting part to calculate a target spring constant depending on a vehicle speed, and uses a spring constant-frequency setting part to calculate a set frequency corresponding to the target spring constant. An oscillation input calculation part generates a signal representing an oscillation input oscillating at the set frequency. A superimposition part sets a value acquired by superimposing the oscillation input on a target driving force to a new target driving force. As a result, the wheel exhibits a minute oscillation in a longitudinal direction, resulting in an input of the minute oscillation to a suspension bush. The suspension bush changes in a spring constant and a damping coefficient depending on the frequency of the input minute oscillation. As a result, the suspension characteristic can be changed.

A method of controlling a suspension system of a vehicle includes identifying an amplitude and a frequency of at least one harmonic event in a topology of a surface to be traversed by the vehicle, and, with a controller, altering at least one response characteristic of at least one adjustable component of the suspension system based on at least one of the amplitude and frequency of the harmonic event. Systems and methods relate to controlling vehicle suspension systems.

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 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 rear axle arrangement for a motor vehicle is disclosed having two independent wheel suspension systems with in each case at least two links and a wheel support. The links producing a connection between the vehicle body and the wheel support and being coupled at their ends in a relatively movable manner via elastic bearings. In the case of static wheel loading, the wheels of the rear axle exhibiting toe-in, which rear axle arrangement is distinguished by at least one elastic bearing of a link having a frequency-dependent bearing stiffness in such a way that, in the case of driving straight ahead and high-frequency dynamic wheel loading, a change into toe-out takes place on account of an increasing bearing stiffness of the bearing and the wheel is pressed into negative camber as a result of the change into toe-out.

A damping control apparatus has a control unit that controls an active actuator that generates a control force for damping a sprung, and the control unit determines a predicted wheel passage position where a wheel is predicted to pass, performs a high-pass filtering on a first road surface displacement-related value, performs a low-pass filtering on a second road surface displacement-related value, calculates a target control force for damping the sprung when the wheel passes through the predicted wheel passage position based on a sum of the first road surface displacement-related value after high-pass filtering and the second road surface displacement-related value after low-pass filtering, and the second road surface displacement-related value has a higher possibility that a position where a control force corresponding to the target control force is generated misaligns with the predicted wheel passage position as compared with the first road surface displacement-related value.

A control unit configured to control a control force generating device configured to generate a control force for damping a sprung portion of a vehicle controls the control force generating device based on a target control force Fcit for damping the sprung portion when a wheel passes through a predicted wheel passing position. The control unit acquires an unsprung displacement z.sub.1i at the predicted wheel passing position, and calculates the target control force as a value proportional to an unsprung displacement z.sub.1ai that is the unsprung displacement z.sub.1i having a phase that has been advanced to advance a phase of a transfer function from the unsprung displacement z.sub.1i to the target control force by a phase advance amount larger than 0 degrees and smaller than 180 degrees.

A damping control device includes a control force generating device and a controller. The controller is configured to acquire road surface displacement related values related to a plurality of road surface displacements in a predetermined sampling zone, acquire an amplitude index indicating a magnitude of an amplitude of the sampled values, determine an operation delay period of the control force generating device based on the magnitude of the amplitude indicated by the amplitude index, calculate target control force for reducing vibration of a vehicle body based on the road surface displacement related values at a predicted passing position where a wheel is predicted to pass after an elapse of the operation delay period from a current time, and transmit, to the control force generating device, a control command for causing the control force generating device to regulate the control force to agree with the target control force.

A vibration attenuation assembly that includes a strut weight configured to attenuate resonant frequency of a vehicle strut assembly. The strut weight has an upper surface and a lower surface. The strut weight has a rod receiving opening that extends from a central area of the upper surface to the lower surface. The upper surface has a conical shape.

A damping control device for a vehicle calculates a weighted sum of a first control force of feedforward control and a second control force of feedback control as a target value of a damping control force. When a degree of a deviation of a path of a rear wheel from a path of a front wheel is larger than a predetermined first degree, the damping control device sets a weight for the second control force to be larger than a weight for the first control force in the weighted sum.