摘要 |
An improved deployment method for a vehicular supplemental restraint system, wherein the timing of restraint deployment in response to a detected a rear impact of sufficient severity is based on the attainment of a predefined characteristic by a signal representative of the slope of a filtered acceleration signal. As a result, the deployment of the restraints is accurately timed for any given crash event, and provides consistent performance regardless of the nature of the impact. The deployment is conditioned upon (1) detection of a predefined level of severity, and (2) a subsequent reduction in the slope of a filtered acceleration signal to a predefined level. Preferably, the predefined level of severity-i.e, the occurrence of a deployment event-is detected when (1) the filtered acceleration exceeds a predefined velocity threshold, and (2) the slope, or gradient, of the filtered acceleration exceeds a first predefined gradient threshold; and deployment is initiated when the gradient of the filtered acceleration subsequently falls to a second predefined gradient threshold. Optionally, additional severity criteria, such as the attainment of a predefined threshold by a filtered version of the filtered acceleration signal, may be used to distinguish between deployment events and non-deployment events.
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