Automotive Systems Laboratory, Inc.

Breed Automotive Technology, Inc.

Daniel N Tabar

Tony Gioutsos

Edward J Gillis

Craig W White

Michael A Piskie

David C Milo

Brian J Zahn

A crash detection system comprises two sensors with complementary performance characteristics, a controller evaluates the signals from both sensors to determine whether an airbag should be activated, when an airbag should be activated and whether multiple stages of the airbag should be activated. The first sensor preferably comprises a ball-in-tube sensor and the second sensor preferably comprises an electronic sensing module comprising an accelerometer and a CPU. The CPU receives signals from the accelerometer and the ball-in-tube sensor. The controller activates the airbag only if both sensors generate fire signals. The controller generates an airbag activation signal based upon crash type and the sum of the times required from the beginning of the crash for both sensors to generate fire signals.

Crash detection system

Motor vehicle safety system deployment is controlled by a biomechanical algorithm that considers a normalized frontal crash velocity and vehicle occupant status in determining safety system deployment strategy. Normalized frontal velocity is determined either by a radar type crash velocity detection system or by adjusting the radar velocity towards a crash velocity determined based on time-to-fire as determined by a single-point algorithm. The radar velocity or the adjusted greater velocity is normalized if necessary for crash type to a frontal velocity equivalent.

Method of determining safety system deployment with crash velocity input

In a system and method for controlling actuation of a vehicle passenger safety device, wherein a first time-varying measure m.sub.1 (t), itself a function of received vehicle acceleration information, is accumulated to obtain a second time-varying measure m.sub.2 (t) for subsequent comparison with a threshold value therefor, the first measure m.sub.1 (t) is 'damped' prior to accumulation by subtracting therefrom a correction value or 'damping factor f.sub.d.' The damping factor f.sub.d may be either a constant or a time-varying function f.sub.d (t) of one or more other time-varying measures, themselves based on received vehicle acceleration information.

Method for damping crash-discrimination measures

A system (10) and method for detecting an envelope of received vehicle acceleration information (a(t)) useful in controlling actuation of a vehicle passenger safety device, wherein consecutive values for received vehicle acceleration information (a(t)) are stored and rank-ordered in a pair of rank-order filters (14, 16) to provide a highest-ranked value (a.sub.H) from among the most-recent half of the stored values, and a highest-ranked value (a.sub.H ') from among the least-recent half of the stored values. The absolute value of the highest-ranked least-current value is taken and subtracted from the highest-ranked most-recent value to obtain a modified jerk measure (j.sub.H *). The absolute value of the thus-generated modified jerk value is taken to obtain a measure (m.sub.1) which tracks the envelope of the received acceleration information and, hence, is useful as an envelope detector when evaluating a crash waveform for purposes of controlling actuation of the safety device.

Envelope detector useful in crash discrimination

A system and method for controlling actuation of a vehicle passenger safety device in response to an event possibly requiring actuation of the safety device, wherein a first measure calculated from received vehicle acceleration information is weighted by a second measure, such as a modified vehicle velocity measure, which is itself evaluative of the relative progress of the event. The weighted first measure is thereafter accumulated and compared to a threshold value, with the safety device being actuated when the resulting accumulated weighted first measure exceeds the threshold value.

System and method for adjusting accumulated crash-discrimination

In a system (10) and method for controlling actuation of a vehicle passenger safety device in response to an event possibly requiring actuation of the safety device, a differential measure (m.sub.1 (t)) is generated based on stored consecutive values for received vehicle acceleration information while a measure (m.sub.2 (t)) correlated with the relative progress of the event is generated by selectively providing as an input to a first accumulator (24) either a weighted transitory value for received acceleration information (a(t)) whenever the transitory value is itself less than or equal to a first predetermined threshold value (x.sub.1), or a weighted alternative value, wherein the alternative value is itself equal to twice the first predetermined threshold value (x.sub.1) minus the transitory value. The differential measure (m.sub.1 (t)) is thereafter combined with the progress measure (m.sub.2 (t)) to effectively 'damp' or weight the former as a function of event progress, whereupon the resulting combination is accumulated in a second accumulator (30) to obtain a measure (m.sub.3 (t)) predictive of event severity, with the safety device being actuated when the predictive measure (m.sub.3 (t)) exceeds a second predetermined threshold value (x.sub.2).

System and method for discriminating short-period crashes

In a system and method for controlling actuation of a vehicle passenger safety device in response to an event possibly requiring actuation of the safety device, stored and rank-ordered values for received vehicle acceleration are used to generate a high-rank jerk measure (j.sub.H), a median-ranked acceleration value (a.sub.M) and a median-rank velocity measure (v.sub.M), while raw acceleration information is further used to generate an 'event-based timer' or event-progress measure (t') . These measures (j.sub.H, a.sub.M, v.sub.M, t') are then used to generate a pair of event-identification measures (m.sub.1, m.sub.2) useful in identifying two specific crash types for which specialized acceleration-based event-severity measures other than the default event-severity measure (m.sub.0) are best suited, specifically, where a series of negative jerks occurring relatively early in an event from a high transitory acceleration identify the occurrence of a sizable vehicle crush, or where a series of small jerks occurring relatively late in an event above a minimum velocity identifies a 'multiple hit' event.

Crash discriminator responsive to early-crush and multiple-hit scenarios

A system and method for controlling actuation of a vehicle passenger safety device in response to an event possibly requiring actuation of the safety device, wherein a modified differentiated measure is generated from received vehicle acceleration information by subtracting the absolute value of a prior-in-time value therefor from its current value, whereby the distortion introduced by negative prior-in-time values is significantly reduced. The resulting modified jerk measure is more useful in discriminating crash events than is a nominal jerk measure, given the latter's predisposition to fail as a useful measure upon encountering negative prior-in-time values.

Growing community of inventors

Troy, MI, United States of America

Daniel N Tabar