US3838890A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adaptive anti-lock brake control
Assignee: Motors Liquidation Co
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Filing: 1973-03-19
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Granted: 1974-10-01
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Expires: 1993-03-19
Abstract
Abstract An anti-lock brake control especially suited to heavy duty trucks with air brakes senses the wheel speed on a given axle and cyclicly releases and applies the brakes on that axle as required to avoid undesirable wheel slip during braking. The control differentiates the speed signal of the fastest wheel, compares the resulting decelration signal to a reference signal and integrates the difference to arrive at a velocity error signal indicating the amount of wheel slip. A comparator compares the velocity error signal to a threshold signal which varies with wheel speed to produce a brake release signal when the threshold is exceeded so that the system is made less sensitive at high wheel speeds than at low speeds. The reference signal is derived from several sources: a minimum g level circuit which always provides a small reference signal, a delayed g level circuit which initially provides the major portion of the reference signal prior to the first release and subsequently gradually supplies a portion of the reference signal a delayed time after brake reapply, an acceleration amplifier which supplies a signal proprotional to positive wheel acceleration in each cycle and partially sustains that value for the succeeding brake release, and an acceleration switch which provides an increase of the reference signal when the positive acceleration exceeds a predetermined value.
Inventors
- 👤 R Wind
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:45
CPC Classifications
B; B60; B60T; B60T8/00; B60T8/17; B60T8/1701; B60T8/1708; B60T8/32; B60T8/321; B60T8/34; B60T8/36; B60T8/361; B60T8/50; B60T8/5018
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
172 words
A control for an anti-lock brake system for a vehicle with braked wheels comprising: means providing a speed signal which represents wheel speed, differentiator means responsive to the speed signal for producing at least one acceleration signal representing wheel acceleration, means for producing a deceleration reference signal representing a rough estimate of vehicle deceleration, integrator means responsive to the acceleration signal and the deceleration reference signal for producing a velocity error signal representing the difference between wheel speed and an estimated vehicle speed, and means responsive to the velocity error signal for producing an output signal requesting brake release when the velocity error signal exceeds a determined threshold value and requesting a brake reapply when the velocity error signal drops below a second lower threshold value, the means for providing a deceleration reference signal including means connected to the differentiator means responsive to the maximum positive wheel acceleration signal during each cycle for providing a continuously variable vehicle deceleration estimate signal comprising a portion of the reference signal for each succeeding cycle.
Claim 2
Dependent Claim
172 words
A control for an anti-lock brake system for a vehicle with braked wheels comprising: means providing a speed signal which represents wheel speed, differentiator means responsive to the speed signal for producing at least one acceleration signal representing wheel acceleration, means for producing a deceleration reference signal representing a rough estimate of vehicle deceleration, integrator means responsive to the acceleration signal and the deceleration reference signal for producing a velocity error signal representing the difference between wheel speed and an estimated vehicle speed, and means responsive to the velocity error signal for producing an output signal requesting brake release when the velocity error signal exceeds a determined threshold value and requesting a brake reapply when the velocity error signal drops below a second lower threshold value, the means for providing a deceleration reference signal including means connected to the differentiator means responsive to the maximum positive wheel acceleration signal during each cycle for providing a continuously variable vehicle deceleration estimate signal comprising a portion of the reference signal for each succeeding cycle.
Claim 3
Dependent Claim
187 words
A control for an anti-lock brake system for a vehicle with braked wheels comprising: means providing a speed signal which represents wheel speed, differentiator means responsive to the speed signal for producing at least one acceleration signal representing wheel acceleration, means for producing a deceleration reference signal representing a rough estimate of vehicle deceleration, integrator means responsive to the acceleration signal and the deceleration reference signal for producing a velocity error signal representing the difference between wheel speed and an estimated vehicle speed, and means responsive to the velocity error signal for producing an output signal requesting brake release when the velocity error signal exceeds a determined threshold value and requesting a brake reapply when the velocity error signal drops below a second lower threshold value, the means for providing a deceleration reference signal including an electronic circuit connected to the differentiator means responsive to an acceleration signal for providing a further signal proportional, within limits, to positive wheel acceleration, and a peak follower circuit responsive to said further signal for providing a portion of the deceleration reference signal which varies as a function of vehicle deceleration.
Claim 4
Dependent Claim
187 words
A control for an anti-lock brake system for a vehicle with braked wheels comprising: means providing a speed signal which represents wheel speed, differentiator means responsive to the speed signal for producing at least one acceleration signal representing wheel acceleration, means for producing a deceleration reference signal representing a rough estimate of vehicle deceleration, integrator means responsive to the acceleration signal and the deceleration reference signal for producing a velocity error signal representing the difference between wheel speed and an estimated vehicle speed, and means responsive to the velocity error signal for producing an output signal requesting brake release when the velocity error signal exceeds a determined threshold value and requesting a brake reapply when the velocity error signal drops below a second lower threshold value, the means for providing a deceleration reference signal including an electronic circuit connected to the differentiator means responsive to an acceleration signal for providing a further signal proportional, within limits, to positive wheel acceleration, and a peak follower circuit responsive to said further signal for providing a portion of the deceleration reference signal which varies as a function of vehicle deceleration.
Claim 5
Dependent Claim
216 words
A control for an anti-lock brake system for a vehicle with braked wheels comprising: means providing a speed signal which represents wheel speed, differentiator means responsive to the speed signal for producing at least one acceleration signal representing wheel acceleration, means for producing a deceleration reference signal representing a rough estimate of vehicle deceleration, integrator means responsive to the acceleration signal and the deceleration reference signal for producing a velocity error signal representing the difference between wheel speed and an estimated vehicle speed, and means responsive to the velocity error signal for producing an output signal requesting brake release when the velocity error signal exceeds a determined threshold value and requesting a brake reapply when the velocity error signal drops below a second lower threshold valve, the means for providing a deceleration reference signal including means connected to the differentiator means and responsive to positive wheel acceleration as indicated by an acceleration signal for providing a continuously variable vehicle deceleration estimate signal that contributes to the deceleration reference signal, the means for producing an output signal including means responsive to the speed signal for changing the determined threshold value substantially proportional to change in the speed signal whereby the control becomes less sensitive to wheel speed changes at high wheel speeds than at low wheel speeds.
Claim 6
Dependent Claim
216 words
A control for an anti-lock brake system for a vehicle with braked wheels comprising: means providing a speed signal which represents wheel speed, differentiator means responsive to the speed signal for producing at least one acceleration signal representing wheel acceleration, means for producing a deceleration reference signal representing a rough estimate of vehicle deceleration, integrator means responsive to the acceleration signal and the deceleration reference signal for producing a velocity error signal representing the difference between wheel speed and an estimated vehicle speed, and means responsive to the velocity error signal for producing an output signal requesting brake release when the velocity error signal exceeds a determined threshold value and requesting a brake reapply when the velocity error signal drops below a second lower threshold valve, the means for providing a deceleration reference signal including means connected to the differentiator means and responsive to positive wheel acceleration as indicated by an acceleration signal for providing a continuously variable vehicle deceleration estimate signal that contributes to the deceleration reference signal, the means for producing an output signal including means responsive to the speed signal for changing the determined threshold value substantially proportional to change in the speed signal whereby the control becomes less sensitive to wheel speed changes at high wheel speeds than at low wheel speeds.
Claim 7
Dependent Claim
212 words
A control for an anti-lock brake system for a vehicle with braked wheels comprising: means providing a speed signal which represents wheel speed, differentiator means responsive to the speed signal for producing at least one acceleration signal representing wheel acceleration, means for producing a deceleration reference signal representing a rough estimate of vehicle deceleration, integrator means responsive to the acceleration signal and the deceleration reference signal for producing a velocity error signal representing the difference between wheel speed and an estimated vehicle speed, and means responsive to the velocity error signal for producing an output signal requesting brake release when the velocity error signal exceeds a determined threshold value and requesting a brake reapply when the velocity error signal drops below a second lower threshold value, the means for providing a deceleration reference signal including means connected to the differentiator means and responsive to positive wheel acceleration as indicated by an acceleration signal for providing a vehicle deceleration estimate signal that contributes to the deceleration reference signal and further including a circuit responsive to the output signal for providing a signal gradually increasing toward a maximum value and contributing to the deceleration reference signal after the output signal requests a brake reapply and terminating when the output signal requests a brake release.
Claim 8
Dependent Claim
212 words
A control for an anti-lock brake system for a vehicle with braked wheels comprising: means providing a speed signal which represents wheel speed, differentiator means responsive to the speed signal for producing at least one acceleration signal representing wheel acceleration, means for producing a deceleration reference signal representing a rough estimate of vehicle deceleration, integrator means responsive to the acceleration signal and the deceleration reference signal for producing a velocity error signal representing the difference between wheel speed and an estimated vehicle speed, and means responsive to the velocity error signal for producing an output signal requesting brake release when the velocity error signal exceeds a determined threshold value and requesting a brake reapply when the velocity error signal drops below a second lower threshold value, the means for providing a deceleration reference signal including means connected to the differentiator means and responsive to positive wheel acceleration as indicated by an acceleration signal for providing a vehicle deceleration estimate signal that contributes to the deceleration reference signal and further including a circuit responsive to the output signal for providing a signal gradually increasing toward a maximum value and contributing to the deceleration reference signal after the output signal requests a brake reapply and terminating when the output signal requests a brake release.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |