Land vehicles – Wheeled – Running gear
Patent
1981-03-17
1983-09-06
Bertsch, Richard A.
Land vehicles
Wheeled
Running gear
B60G 1704, B61F 522, G05D 1900, F16F 1500
Patent
active
044025270
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a vehicle body vibration control apparatus in which springs for supporting the vehicle body are placed in juxtaposition with a fluid operating mechanism which is controlled through a fluid control device from the results detected by a vibration detector, thereby improving the riding quality.
BACKGROUND ART
As a vehicle body vibration control system, a system comprising a spring system provided with a control air spring, for controlling the internal pressure of the control air spring with the vibration acceleration of the vehicle body as a control input, is under development. This system has the advantage that a vehicle supporting spring other than the air spring holds a reference position of a suspension system. In view of the fact that the control input comprises the vibration acceleration of the vehicle body only, however, it is an important problem how to determine a compensator circuit for compensating the vibration acceleration and transferring it to a control device including an amplifier, a servo valve and the like. A compensator circuit presently suggested produces of a first order lead characteristic and a first order lag characteristic given as ##EQU1## or including also a second order lag characteristic, as ##EQU2## Kb: Transfer function of the compensator circuit K: Gain constant natural frequency which is determined by the vehicle body support spring and the vehicle body mass can be kept at a low level, but the problem point is that the response acceleration of the vehicle body increases somewhat is the in upper and lower frequency ranges other than the frequencies about the natural frequency.
DISCLOSURE OF INVENTION
The present invention is such that the responsiveness of the vehicle body to the vibration acceleration has no peak over a wide range of frequency, or especially in low frequency ranges, thus extremely improving the riding quality.
The present invention is characterized in that, in a vehicle body vibration control system including a vehicle body support spring provided with a fluid operating mechanism for controlling the internal pressure of the fluid operating mechanism through a fluid control device from the results detected by a vibration detector and, the detected vibration acceleration of the vehicle body is compensated by feedback by a compensator circuit utilizing a lead-lag circuit and an integrator, the output of which is used as a control signal for the fluid control device, so that the response of the vehicle body on the vibration acceleration has no peak in low frequency ranges and smoothly decreases with the increase of the frequency. Thus, as compared with the conventional vehicles, the riding quality is extremely improved.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a circuit diagram of a vibration control apparatus of a vehicle body showing an embodiment of the present invention,
FIG. 2 is a circuit diagram showing an example of the compensator circuit in FIG. 1,
FIG. 3 is a gain diagram showing a response magnification of the system,
FIG. 4 is a Bode diagram of a loop transfer function of the system for showing the stability,
FIG. 5 is a diagram showing the relation between the time constant of a phase lead element and the control characteristics,
FIG. 6 is a diagram showing the gain characteristics of the system in another compensator circuit,
FIG. 7 is a circuit diagram showing an example in which the present invention is applied to a vibration control apparatus of a vehicle body including a preview control compensation,
FIG. 8 is a gain diagram of the system of FIG. 7, and
FIGS. 9 and 10 are circuit diagrams showing a method of setting a time lag .tau. against speed with respect to the preview control compensation.
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described below in detail with reference to some embodiments. FIG. 1 is a circuit diagram showing an embodiment of a vibration control apparatus of a vehicle body according to the present invention, and FIG. 2 is a circuit
REFERENCES:
patent: 3124368 (1964-03-01), Corley et al.
patent: 3873123 (1975-03-01), Joneleit
patent: 3995883 (1976-12-01), Glaze
patent: 4164664 (1979-08-01), Kasiewicz
Beppu Tadashi
Kakehi Yutaka
Kasai Kenjirou
Terada Katsuyuki
Bertsch Richard A.
Hitachi , Ltd.
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