Electronic controlled fluid suspension system for controlling roll and pitch of a vehicle body
First Claim
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1. An electronic controlled fluid suspension system for a vehicle comprising:
- a fluid suspension provided for each of a plurality of wheels of the vehicle;
a height detection means provided for each of the plurality of wheels for detecting a height of a body of the vehicle at said each wheel and for generating a height signal;
a roll detection means responsive to the height signals for generating a roll signal representing a roll of the body;
a low-pass filtering means for passing only a component of the roll signal having a frequency lower than a threshold frequency;
a driving state detection means for detecting driving parameters that affect a lateral acceleration of the body;
a threshold changing means responsive to the detected driving parameters for changing the threshold frequency of the low-pass filtering means to a higher value when the body is expected to develop a roll;
a target determination means for determining a target roll signal;
an attitude control means for generating a control amount in order to feedback-control the roll signal filtered by the low-pass filtering means to approach the target roll signal; and
a fluid flow control means responsive to the control amount for controlling fluid flow to and from each of the fluid suspensions.
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Abstract
In controlling roll and pitch of a vehicle body responsive to a displacement signal produced at each wheel of the vehicle, each signal is low-pass-filtered with a certain threshold frequency to prevent hunting of the control due to an excessively high frequency component (such as noise or a component corresponding to road irregularities) of the signal. According to this invention, the threshold frequency is changed to a higher value in order to get quick attitude control when the roll or pitch of the body is expected, while it is set at a lower value when no such attitude change is expected in order to prevent hunting of the control.
28 Citations
6 Claims
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1. An electronic controlled fluid suspension system for a vehicle comprising:
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a fluid suspension provided for each of a plurality of wheels of the vehicle; a height detection means provided for each of the plurality of wheels for detecting a height of a body of the vehicle at said each wheel and for generating a height signal; a roll detection means responsive to the height signals for generating a roll signal representing a roll of the body; a low-pass filtering means for passing only a component of the roll signal having a frequency lower than a threshold frequency; a driving state detection means for detecting driving parameters that affect a lateral acceleration of the body; a threshold changing means responsive to the detected driving parameters for changing the threshold frequency of the low-pass filtering means to a higher value when the body is expected to develop a roll; a target determination means for determining a target roll signal; an attitude control means for generating a control amount in order to feedback-control the roll signal filtered by the low-pass filtering means to approach the target roll signal; and a fluid flow control means responsive to the control amount for controlling fluid flow to and from each of the fluid suspensions. - View Dependent Claims (2, 3)
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4. An electronic controlled fluid suspension system for a vehicle comprising:
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a fluid suspension provided for each of a plurality of wheels of the vehicle; a height detection means provided for each of the plurality of wheels for detecting a height of a body of the vehicle at said each wheel and for generating a height signal; a pitch detection means responsive to the height signals for generating a pitch signal representing a pitch of the body; a low-pass filtering means for passing only a component of the pitch signal having a frequency lower than a threshold frequency; a driving state detection means for detecting driving parameters that affect a longitudinal acceleration of the body; a threshold changing means responsive to the detected driving parameters for changing the threshold frequency of the low-pass filtering means to a higher value when the body is expected to develop a pitch; a target determination means for determining a target pitch signal; an attitude control means for generating a control amount in order to feedback-control the pitch signal filtered by the low-pass filtering means to approach the target pitch signal; and a fluid flow control means responsive to the control amount for controlling fluid flow to and from each of the fluid suspensions. - View Dependent Claims (5, 6)
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Specification