Airbag sensor system

• US 6,434,461 B1
• Filed: 07/25/2000
• Issued: 08/13/2002
• Est. Priority Date: 01/28/1998
• Status: Expired due to Term

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Jacob, Lutz, Weiss, Georg
• Primary Examiner(s): Chin, Gary
• Application Number:
  US09/601,009
• Time in Patent Office: 749 Days
• Field of Search: 701/45, 701/46, 701/47, 340/436, 340/438, 340/903, 307/10.1, 280/734, 280/735, 180/274, 180/282, 342/70, 342/72
• US Class Current: 701/45
• CPC Class Codes: B60R 2021/0006 Lateral collision
• CPC Class Codes: B60R 21/013 including means for detecting collisions, impending collisions or roll-over
• CPC Class Codes: B60R 21/0134 responsive to imminent contact with an obstacle , e.g. using radar systems
• CPC Class Codes: G01S 13/348 using square or rectangular modulation, e.g. diplex radar for ranging over short distances
• CPC Class Codes: G01S 13/584 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/93274 on the side of the vehicles

Abstract

The aim of the invention is to generate a timely triggering signal for an effective unfolding of an airbag and, at the same time, to take the relative velocity of the collision opponent into account as a triggering criterion. To this end, the invention provides that two interspaced sensors, which emit millimeter waves, are integrated in each vehicle body door. The measuring signals of said sensors are generated by means of a multi-frequency modulation method. The invention also provides that during a signal processing operation using radar technology, the obtained measuring signals are turned into velocity values (Vn) and distance values (R) according to individual echo centers of the collision object. In addition, the transversal velocity (V_q) with regard to the door surface is detected from said values in a series-connected situation analysis module. A classification of the collision object results from the measured values and a criterion is obtained from a subtraction of both sensor measurement outcomes. The invention can be used for triggering a side airbag in a motor vehicle.

Claims

1. A sensor system for the triggering of a side airbag in a vehicle having at least one door and at least one vehicle side, said sensor system comprised of;

(a) at least first and second millimeter wave emitting sensors (1) and (2) spaced at least two decimeters apart and integrated in said at least one door or said at least one vehicle side for respectively generating measurement signals by a multi-frequency modulation process;

(b) signal processing means (3) for receiving said measurement signals, resolving a collision object (5) into individual echo centers (6) using radar signals, and determining the distance value (Rn) and the transverse velocity (Vq) of said echo centers relative to the at least one door, and

(c) a situation analysis module (4) downstream of said signal processing means, for differentiating the two sensor measurement signals, to

(1) Classify said collision object according to geometric characteristics and

(2) determine whether a parallel passage or an impact situation exists,

wherein from an analytical correlation of the determined transverse velocity (Vq), the classified collision object and the determined impact situation in the situation analysis module (4), an actuation impulse (Ai) for the actuation electronic of the airbag is generated in a threatening situation.

2. A sensor system according to claim 1, wherein the sensors (1 and 2) are 76-GHz-high frequency front end receivers.

3. A sensor system according to claim 1, wherein the multi-frequency modulation process is a “

two-frequency process”

with a separation of 50 MHz between the two frequencies.

4. A sensor system for the triggering of a side airbag in a vehicle having at least one door and at least one vehicle side, said sensor system comprised of:

(a) at least first and second millimeter wave emitting sensors (1) and (2) spaced at least two decimeters apart and integrated in said at least one door or said at least one vehicle side for respectively generating measurement signals by a multi-frequency modulation process;

(b) signal processing means (3) for;

receiving said measurement signals,

resolving a collision object (5) into individual echo centers (6) using radar signals,

tracking said echo centers Rn and Vn with each of the respective sensors (1) and (2) over time,

determining the distance value (Rn) and the transverse velocity (Vq) of said echo centers relative to the at least one door,

selecting from the various velocities (Vn) of the echo centers the line of maximum Doppler frequency (max detected Vr) as the relative speed (Vr) of the collision object (5),

calculating, from the direction and relative speed (Vr) of the collision object, the velocity (Vq) of the collision object perpendicular to said at least one door,

extracting collision object characteristics from FFT-data over multiple evaluation cycles for the task of object recognition, and using a recognition algorithm to carry out object size or shape classification on the basis of the extracted collision object characteristics,

(c) a situation analysis module (4) downstream of said signal processing means, wherein;

the classified object size or shape, the calculated perpendicular velocity (Vq), and the tracks of the Rn and Vn of the echo centers are used by said situation analysis module to determine danger of impact of the collision object on the at least one door or said at least one vehicle side, and

when

(i) an appropriate size or shape of the collision object (5) is classified,

(ii) the differences between the velocity values Vn and the distance values Rn from the respective sensors (1) and (2) are indicative of an impact situation, and

(iii) the perpendicular velocity (Vq) exceeds a threshold value,

an actuation impulse (Ai) is triggered for the actuation electronic of the airbag.