An object of the present invention is to provide a suspension control apparatus allowing a vehicle state to be easily estimated with use of a vehicle height sensor. A controller 11 includes an external force estimation portion 31, which calculates an external force applied to a vehicle body from a displacement calculated from a vehicle height sensor 10, a vertical force calculation portion 32A, which calculates a vertical force of the vehicle body 1 from the calculated external force, a sprung acceleration calculation portion 32B, which calculates an acceleration from the calculated vertical force, a filter portion 32C, which estimates a sprung speed of the vehicle body 1 from the calculated acceleration, and a damping characteristic determination portion 14, which acquires a damping characteristic based on the estimated sprung speed.

A work vehicle includes a vehicle body, a plurality of traveling devices disposed on the right and left sides on the front and rear sides of the vehicle body respectively, a plurality of bending link mechanisms configured to liftably support each one of the traveling devices to the vehicle body and a plurality of drive operating devices capable of changing the posture of each one of the plurality of bending link mechanisms. The vehicle body is split into a front side body section and a rear side body section. The front side body section and the rear side body section are configured to be bendably pivotable relative to each other via a pivot interlocking mechanism.

1. A device for decoupling vibrations between two systems and a working machine

2. A device together with an assigned working machine for decoupling vibrations between two systems (2, 4) in the form of spring-mass oscillators, of which one system (2) is assigned to a motion machine and the other system (4) is assigned to an operator operating the motion machine, which other system (4) at least partially performs motions about a transverse axis (Q) during driving motions of the motion machine and in doing so is subject to vertical motions in the direction of a vertical axis (z) at an absolute vertical speed (.sub.z1,1), which serves as an input variable of control devices and/or regulating devices, which control a damping system (8) of the one (2) and/or the other (4) system to compensate for the vibrations, is characterized in that the respective pitch motion of the other system (4) is detected by at least one rotation rate sensor, the respective measured value (.sub.1) of which, preferably amplified by only a predeterminable factor (L.sub.1), results in the absolute vertical speed (.sub.z1,1) as input variable.

A roll vibration damping control system includes an electronic control unit configured to: compute a sum of a product of a roll moment of inertia and a roll angular acceleration of a vehicle body, a product of a roll damping coefficient and a first-order integral of the roll angular acceleration, and a product of an equivalent roll stiffness of the vehicle and a second-order integral of the roll angular acceleration, as a controlled roll moment to be applied to the vehicle body; compute a roll moment around a center of gravity of a sprung mass as a correction roll moment, the roll moment being generated by lateral force on wheels due to roll motion; and compute a target roll moment based on a value obtained by correcting the controlled roll moment with the correction roll moment.

A vehicle attitude control device includes a controller including a low-pass filter. The controller calculates a manipulated variable of the actuator that allows the roll of the vehicle to be suppressed. The controller processes the roll angle acceleration with the low-pass filter, integrates the roll angle acceleration in which a high-frequency component has been removed by the low-pass filter, and converts a roll angle velocity obtained by the integration, into the manipulated variable. The low-pass filter has a first vehicle speed-cutoff frequency characteristic in which a cutoff frequency becomes higher with increase in the vehicle speed, and the first vehicle speed-cutoff frequency characteristic is designed such that a peak frequency in roll vibration coincides with a local minimum roll frequency in wheelbase filtering, the roll vibration being amplified by a dead time and a phase delay in control by the controller.

A roll vibration damping control system includes an electronic control unit configured to: compute a sum of a product of a roll moment of inertia and a roll angular acceleration of a vehicle body, a product of a roll damping coefficient and a first-order integral of the roll angular acceleration, and a product of an equivalent roll stiffness of the vehicle and a second-order integral of the roll angular acceleration, as a controlled roll moment to be applied to the vehicle body; compute a roll moment around a center of gravity of a sprung mass as a correction roll moment, the roll moment being generated by lateral force on wheels due to roll motion; and compute a target roll moment based on a value obtained by correcting the controlled roll moment with the correction roll moment.

Methods and apparatus to compensate for body roll in vehicle weight calculations are disclosed. An example method includes receiving sensor data from sensors of a vehicle, determining a weight of the vehicle and determining a body roll of the vehicle. The example method further includes comparing the body roll to a threshold and, if the body roll satisfies the threshold, adjusting the determined weight of the vehicle based on the determined body roll and properties of a suspension system of the vehicle.

A roll vibration damping control system includes an electronic control unit configured to: compute a sum of a product of a roll moment of inertia and a roll angular acceleration of a vehicle body, a product of a roll damping coefficient and a first-order integral of the roll angular acceleration, and a product of an equivalent roll stiffness of the vehicle and a second-order integral of the roll angular acceleration, as a controlled roll moment to be applied to the vehicle body; compute a roll moment around a center of gravity of a sprung mass as a correction roll moment, the roll moment being generated by lateral force on wheels due to roll motion; and compute a target roll moment based on a value obtained by correcting the controlled roll moment with the correction roll moment.

A method for controlling a suspension system for a vehicle to obtain optimal parameters for the damping coefficients of the vehicle suspension that minimize acceleration along a heave axis, angular acceleration around a roll axis and angular acceleration around a pitch axis is provided. These parameters may be recorded during the tuning phase or may also be continuously obtained during use of the vehicle by an end user. Also disclosed is a suspension system for a vehicle configured to advantageously operate according to the method.

An object of the present invention is to provide a suspension control apparatus allowing a vehicle state to be easily estimated with use of a vehicle height sensor. A controller 11 includes an external force estimation portion 31, which calculates an external force applied to a vehicle body from a displacement calculated from a vehicle height sensor 10, a vertical force calculation portion 32A, which calculates a vertical force of the vehicle body 1 from the calculated external force, a sprung acceleration calculation portion 32B, which calculates an acceleration from the calculated vertical force, a filter portion 32C, which estimates a sprung speed of the vehicle body 1 from the calculated acceleration, and a damping characteristic determination portion 14, which acquires a damping characteristic based on the estimated sprung speed.