Method for establishing a release criterion for restraining means
First Claim
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1. A method for forming a deployment criterion for a restrainer in a vehicle, comprising the steps of:
- measuring an acceleration signal of the vehicle in at least one direction;
analyzing the acceleration signal, upon measuring the acceleration signal, in a first time segment;
determining a nondeployment event based upon characteristic features indicating a crash event in which the restrainer should not be deployed;
reducing a cut-off frequency of a low-pass filter for a predetermined time segment if a nondeployment event is determined;
filtering the acceleration signal in the low-pass filter, yielding a filtered acceleration signal;
integrating the acceleration signal, yielding an integrated acceleration; and
comparing the integrated acceleration to a deployment threshold, the deployment threshold having a higher value at low accelerations than at high accelerations, the deployment threshold being formed as a function of the filtered acceleration signal.
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Abstract
A clear distinction between deployment and nondeployment situations is made by subjecting the measured acceleration of a vehicle to low-pass filtration, forming a deployment threshold as a function of the filtered acceleration signal, analyzing an acceleration signal, as soon as it is measured, in a first time segment to determine characteristic features indicating a crash event in which the restraint device should not be deployed and reducing the cut-off frequency of the low-pass filter for a predetermined time segment if a nondeployment situation of this type is detected.
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Citations
6 Claims
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1. A method for forming a deployment criterion for a restrainer in a vehicle, comprising the steps of:
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measuring an acceleration signal of the vehicle in at least one direction;
analyzing the acceleration signal, upon measuring the acceleration signal, in a first time segment;
determining a nondeployment event based upon characteristic features indicating a crash event in which the restrainer should not be deployed;
reducing a cut-off frequency of a low-pass filter for a predetermined time segment if a nondeployment event is determined;
filtering the acceleration signal in the low-pass filter, yielding a filtered acceleration signal;
integrating the acceleration signal, yielding an integrated acceleration; and
comparing the integrated acceleration to a deployment threshold, the deployment threshold having a higher value at low accelerations than at high accelerations, the deployment threshold being formed as a function of the filtered acceleration signal. - View Dependent Claims (2, 3, 4, 5, 6)
integrating the acceleration signal across multiple consecutive, short time windows in the first time segment to detect nondeployment events;
subjecting the integrated signal to a threshold value decision; and
determining a nondeployment event if the integrated signal initially drops below a lower threshold due to a vehicle deceleration and subsequently exceeds an upper threshold due to elastic vibrations in a body of the vehicle.
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6. The method according to claim 5, further comprising the steps of:
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comparing the integrated signal to a further threshold lower than the lower threshold, the signal only dropping below the further threshold in the case of deployment crashes; and
determining a nondeployment event only if the integrated signal does not drop below the further threshold.
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Specification