US5430646A — System and method for controlling damping force c…

Claim 1

Independent Claim 212 words

A damping force coefficient controlling system for a vehicular suspension, comprising: a damper, said damper including means responsive to a control signal for varying a damping force coefficient of said damper in response to the control signal; first detecting means for detecting a vertical acceleration of a sprung mass of a vehicular body; second detecting means for detecting a relative speed between the sprung mass and an unsprung mass; deriving means responsive to said first and second detecting means for deriving a sprung mass vibration frequency using the vertical acceleration and relative speed respectively detected by said first and second detecting means; determining means for determining whether the derived sprung mass vibrating frequency is lower than a predetermined dead frequency (fn), said predetermined dead frequency being a sprung mass vibration frequency which is higher than a sprung mass vibration resonance frequency and a frequency at which a sprung mass vibration transmissibility is uneffected irrespective of the magnitude of the damping coefficient which said damper is conditioned to produce; and controlling means responsive to said determining means for outputting the control signal to the damper to change the damping force coefficient in accordance with the determination of whether the derived sprung mass vibrating frequency is lower than a predetermined dead frequency or not.

Claim 2

Dependent Claim 212 words

A damping force coefficient controlling system for a vehicular suspension, comprising: a damper, said damper including means responsive to a control signal for varying a damping force coefficient of said damper in response to the control signal; first detecting means for detecting a vertical acceleration of a sprung mass of a vehicular body; second detecting means for detecting a relative speed between the sprung mass and an unsprung mass; deriving means responsive to said first and second detecting means for deriving a sprung mass vibration frequency using the vertical acceleration and relative speed respectively detected by said first and second detecting means; determining means for determining whether the derived sprung mass vibrating frequency is lower than a predetermined dead frequency (fn), said predetermined dead frequency being a sprung mass vibration frequency which is higher than a sprung mass vibration resonance frequency and a frequency at which a sprung mass vibration transmissibility is uneffected irrespective of the magnitude of the damping coefficient which said damper is conditioned to produce; and controlling means responsive to said determining means for outputting the control signal to the damper to change the damping force coefficient in accordance with the determination of whether the derived sprung mass vibrating frequency is lower than a predetermined dead frequency or not.

Claim 3

Dependent Claim 90 words

A damping force coefficient controlling system as set forth in claim 1, wherein said controlling means derives a maximum damping coefficient value (MD) from a preset maximum damping coefficient schedule according to the derived sprung mass vibrating frequency (H z ) and wherein the maximum damping coefficient value (MD) is set to a predetermined value when the sprung mass vibrating frequency is less than the predetermined dead frequency (fn), and the maximum damping coefficient (MD) is reduced as the sprung mass vibrating frequency increases above said predetermined dead frequency (fn).

Claim 4

Dependent Claim 97 words

A damping force coefficient controlling system as set forth in claim 2, wherein said controlling means derives a sprung mass speed (V) according to a first output signal of said first detecting means, derives an optimum damping coefficient control point according to values of the derived sprung mass speed (V) and a second output signal of said second detecting means, and outputs said control signal to said damper so that said damper is conditioned to produce an optimum damping force coefficient with the maximum damping force coefficient (MD) as an upper limit of the damping force coefficient.

Claim 5

Dependent Claim 107 words

A damping force coefficient controlling system as set forth in claim 1, wherein said deriving means derives the sprung mass vibrating frequency (Hz) as follows: ##EQU1## wherein G1 denotes a vertical acceleration of the sprung mass when a sprung mass speed derived by integrating an output of said first detecting means is zero, G2 denotes a vertical acceleration when a relative speed between the sprung mass and unsprung mass detected by the second detecting means, is zero, and T o denotes a time interval from a point in time when the sprung mass speed is zero to a point in time when the relative speed is zero.

Claim 6

Dependent Claim 92 words

A damping force coefficient controlling system as set forth in claim 4, wherein said controlling means determines whether the sprung mass speed has a sign which is the same as that of the sprung mass relative speed, and outputs the control signal to the damper so that the damping force coefficient is set to a higher damping force coefficient value (H) until the sprung mass speed has the same sign as that of the relative speed when the vibrating frequency Hz is not lower than the predetermined dead frequency f n .

Claim 7

Dependent Claim 91 words

A damping force coefficient controlling system as set forth in claim 5, wherein said controlling means determines whether the sprung mass speed has the same sign as that of the relative speed and outputs the control signal to the damper so that the damping force coefficient of said damper is set to a higher damping force coefficient (H) when the sprung mass speed has the same sign as that of the relative speed and the sprung mass vibrating frequency Hz is not lower than the predetermined dead frequency f n .

Claim 8

Dependent Claim 91 words

A damping force coefficient controlling system as set forth in claim 6, wherein said controlling means determines whether the sprung mass speed has the same sign as that of the relative speed and outputs the control signal to said damper so that the damping force coefficient of said damper is set to a medium damping force coefficient (M) until the sprung mass speed has the same sign as that of the relative speed when the sprung mass vibrating frequency H z is less than the predetermined dead frequency f n .

Claim 9

Dependent Claim 193 words

A damping force coefficient controlling system comprising: a damper, said damper including means responsive to a control signal for varying a damping force coefficient of said damper in response to the control signal; first detecting means for detecting a vertical acceleration of a sprung mass of a vehicular body; second detecting means for detecting a relative speed between the sprung mass and an unsprung mass; deriving means responsive to said first and second detecting means for deriving a sprung mass vibration frequency; determining means for determining whether the derived sprung mass vibrating frequency is lower than a predetermined dead frequency; and control means responsive to said determining means for outputting the control signal to said damper to change the damping force coefficient in accordance with the determination of whether the derived sprung mass vibrating frequency is lower than a predetermined dead frequency or not; and wherein said predetermined dead frequency (fn) is defined as a sprung mass vibrating frequency at which a sprung mass vibration transmissibility characteristic when the damper damping force coefficient is relatively high coincides with a sprung mass vibration transmissibility characteristic when the damper damping force coefficient is relatively low.

Claim 10

Dependent Claim 193 words

A damping force coefficient controlling system comprising: a damper, said damper including means responsive to a control signal for varying a damping force coefficient of said damper in response to the control signal; first detecting means for detecting a vertical acceleration of a sprung mass of a vehicular body; second detecting means for detecting a relative speed between the sprung mass and an unsprung mass; deriving means responsive to said first and second detecting means for deriving a sprung mass vibration frequency; determining means for determining whether the derived sprung mass vibrating frequency is lower than a predetermined dead frequency; and control means responsive to said determining means for outputting the control signal to said damper to change the damping force coefficient in accordance with the determination of whether the derived sprung mass vibrating frequency is lower than a predetermined dead frequency or not; and wherein said predetermined dead frequency (fn) is defined as a sprung mass vibrating frequency at which a sprung mass vibration transmissibility characteristic when the damper damping force coefficient is relatively high coincides with a sprung mass vibration transmissibility characteristic when the damper damping force coefficient is relatively low.

Claim 11

Dependent Claim 85 words

A damping force coefficient controlling system as set forth in claim 8, wherein said deriving means derives the sprung mass vibrating frequency (H z ) by: deriving the sprung mass speed (V) by integrating an acceleration indicative output of the first detecting means; measuring a time interval (T 0 ) from a time when the sprung mass speed (V) peaks to a time when the sprung mass speed (V) reaches zero; and deriving the sprung mass vibrating frequency, (H z ) as follows: H.sub.z =1/(4×T.sub.0)

Claim 12

Independent Claim 192 words

A method for controlling a vehicular suspension having a damper which includes a damping force changing means which is responsive to an input control signal for changing the damping force coefficient of the damper at a plurality of stages, comprising the steps of: detecting a vertical acceleration of a sprung mass of a vehicular body; detecting a relative speed between an unsprung mass and the sprung mass; deriving a sprung mass vibrating frequency on the basis of said vertical acceleration and said relative speed; determining whether the derived sprung mass vibrating frequency is equal to or higher than a predetermined dead frequency or not; setting said predetermined dead frequency as a sprung mass vibration frequency which is higher than a sprung mass vibration resonance frequency and a frequency at which a sprung mass vibration transmissibility is uneffected irrespective of the magnitude of the damping coefficient which said damper is conditioned to produce; and outputting the control signal to the damper to change the damping force coefficient on the basis of a result of the determination of whether the derived sprung mass vibrating frequency is lower than a predetermined dead frequency or not.

Claim 13

Independent Claim 192 words

A method for controlling a vehicular suspension having a damper which includes a damping force changing means which is responsive to an input control signal for changing the damping force coefficient of the damper at a plurality of stages, comprising the steps of: detecting a vertical acceleration of a sprung mass of a vehicular body; detecting a relative speed between an unsprung mass and the sprung mass; deriving a sprung mass vibrating frequency on the basis of said vertical acceleration and said relative speed; determining whether the derived sprung mass vibrating frequency is equal to or higher than a predetermined dead frequency or not; setting said predetermined dead frequency as a sprung mass vibration frequency which is higher than a sprung mass vibration resonance frequency and a frequency at which a sprung mass vibration transmissibility is uneffected irrespective of the magnitude of the damping coefficient which said damper is conditioned to produce; and outputting the control signal to the damper to change the damping force coefficient on the basis of a result of the determination of whether the derived sprung mass vibrating frequency is lower than a predetermined dead frequency or not.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1998-07-03	1999-01-02	1999-07-04	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2002-07-03	2003-01-02	2003-07-04	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2006-07-03	2007-01-02	2007-07-04	$7700.00	Window Closed / Lapsed

System and method for controlling damping force coefficient of shock absorber applicable to automotive supension

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