Method and system for controlling a vehicle occupant safety system based on crash severity
First Claim
1. A method of controlling a vehicle occupant safety restraint system including an airbag, said method comprising the steps of;
- generating an acceleration signal indicative of vehicle acceleration;
determining a jerk signal from a slope of the acceleration signal;
determining a velocity signal by integrating the acceleration signal;
determining a predicted velocity indicative of a relative velocity between a passenger and the vehicle at a time equal to a present time plus an airbag inflation time in accordance with the velocity signal, the jerk signal, the acceleration signal and a deploy time period required to deploy the safety restraint system;
subtracting the predicted velocity from a velocity threshold to obtain a difference value and applying a weighting factor to the difference value to limit the predicted velocity to values between zero and one; and
generating a deployment signal to activate the occupant safety restraint system when the predicted velocity exceed the velocity threshold.
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Accused Products
Abstract
A method and system for controlling a vehicle occupant safety system based on crash severity. The system uses an acceleration signal indicating the acceleration of the vehicle upon occurrence of a crash to determine whether to trigger a restraint device. A controller implements a crash sensing algorithm to determine whether the severity of the crash warrants deployment of the safety restraint. The algorithm uses a predicted velocity and an acceleration peak time derived from the acceleration signal. The predicted velocity is indicative of the relative velocity between the passenger and the vehicle at a predetermined time following detection of a crash event. The acceleration peak time is the time period between peak acceleration values that correspond to contacting of significant structural elements of the vehicle, such as the bumper and the radiator. The two values are compared to their respective thresholds and if both of them exceed their thresholds then a deployment signal is generated to trigger the safety restraint.
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Citations
17 Claims
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1. A method of controlling a vehicle occupant safety restraint system including an airbag, said method comprising the steps of;
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generating an acceleration signal indicative of vehicle acceleration;
determining a jerk signal from a slope of the acceleration signal;
determining a velocity signal by integrating the acceleration signal;
determining a predicted velocity indicative of a relative velocity between a passenger and the vehicle at a time equal to a present time plus an airbag inflation time in accordance with the velocity signal, the jerk signal, the acceleration signal and a deploy time period required to deploy the safety restraint system;
subtracting the predicted velocity from a velocity threshold to obtain a difference value and applying a weighting factor to the difference value to limit the predicted velocity to values between zero and one; and
generating a deployment signal to activate the occupant safety restraint system when the predicted velocity exceed the velocity threshold. - View Dependent Claims (2, 3)
determining a velocity signal by integrating the acceleration signal;
determining a displacement signal by integrating the velocity signal; and
determining the predicted displacement value based upon the displacement signal, velocity signal, acceleration signal and a deploy time period required to deploy the safety restraint system.
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4. A method of controlling a vehicle occupant safety restraint system including an airbag, said method comprising the steps of;
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generating an acceleration signal indicative of vehicle acceleration;
determining a jerk signal from a slope of the acceleration signal, determining a velocity signal by integrating the acceleration signal;
determining a predicted velocity in accordance with the velocity signal, the jerk signal, the acceleration signal and a deploy time period required to deploy the safety restraint system;
determining an acceleration peak time indicative of a time interval between a first maximum acceleration level and a second maximum acceleration level;
comparing the predicted velocity to a velocity threshold to obtain a difference value;
applying a weighting factor to the difference value to limit the predicted velocity to values with a predetermined range; and
comparing the acceleration peak time to a predetermined acceleration time threshold; and
generating a deployment signal to activate the occupant safety restraint system when the predicted velocity exceeds the velocity threshold and the acceleration peak time is less than the acceleration time threshold. - View Dependent Claims (5, 6, 7, 8, 9)
determining a velocity by integrating the acceleration signal;
determining a displacement by integrating the velocity; and
determining the predicted displacement based upon the displacement, the velocity, the acceleration signal and a deploy time period required to deploy the safety restraint system.
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8. The method as in claim 7, further comprising the steps of:
- detecting a pole crash condition by
determining a minimum acceleration peak value;
determining whether a difference between the first maximum acceleration peak value and the minimum acceleration peak value is less than a predetermined difference; and
determining whether the second acceleration maximum peak value is greater than the first acceleration maximum peak value; and
generating a deployment signal if a pole crash condition is detected.
- detecting a pole crash condition by
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9. The method as in claim 4, wherein said step of comparing is further defined by subtracting the predicted velocity from the velocity threshold to find the difference value;
- and multiplying the difference value by the weighting factor to limit the predicted velocity to values between zero and one.
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10. A system for controlling a vehicle safety restraint system, comprising:
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a sensor for sensing vehicle acceleration and generating an acceleration signal in response;
an occupant safety restraint device; and
a controller operatively connected to said sensor and said occupant safety restraint device, said controller adapted to calculate a predicted velocity indicative of the relative velocity between a passenger and the vehicle at a predetermined time following a crash event from said acceleration signal, and an acceleration peak time value, compare the predicted velocity to a velocity threshold, and the acceleration peak time value with a predetermined acceleration value; and
generate a deployment signal to activate said occupant safety restraint device when said predicted velocity exceeds said velocity threshold and said acceleration peak time value is less than said predetermined acceleration peak time threshold.- View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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Specification