Control system for vehicle safety device

• US 5,262,949 A
• Filed: 03/08/1993
• Issued: 11/16/1993
• Est. Priority Date: 02/20/1990
• Status: Expired due to Term

• Current Assignee: Bosch Automotive Systems Corporation (Robert Bosch GmbH)
• Original Assignee: Zexel Corporation (Robert Bosch GmbH)
• Inventors: Kaneko, Hideyuki, Okano, Masami, Ishizuka, Hideki, Takeuchi, Kunihiro
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): PARK, COLLIN
• Application Number:
  US08/028,608
• Time in Patent Office: 253 Days
• Field of Search: 364/424.05, 280/728, 280/734, 280/735, 280/801, 340/436, 340/438, 180/271, 180/282
• US Class Current: 701/46
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value
• CPC Class Codes: B60R 21/0133 by integrating the amplitude of the input signal

Abstract

A control system for a vehicle safety device includes an acceleration detecting device for detecting the deceleration of the vehicle, an integrating device for integrating the deceleration from the acceleration detecting device, a collision judgment device for comparing the integral value, obtained by the integrating device, with a trigger threshold level so as to judge whether or not a collision has occurred, and for outputting an activation instruction signal when the collision judgment device judges that the collision has occurred, and a drive circuit responsive to the activation instruction signal from the collision judgment device so as to activate the vehicle safety device. The control system further includes a deceleration compensation device for adjusting the trigger threshold level in accordance with the deceleration in such a manner that the trigger threshold level becomes low when the deceleration is large and that the trigger threshold level becomes high when the deceleration is small.

Claims

1. A control system for a vehicle safety device comprising:

(a) acceleration detecting means for detecting deceleration of a vehicle;

(b) integrating means for integrating the deceleration from said acceleration detecting means;

(c) collision judgment means for comparing an integral value, obtained by said integrating means, with a trigger threshold level to judge whether or not a collision has occurred, and for outputting an activation instruction signal when said collision judgment means judges that the collision has occurred;

(d) a drive circuit responsive to said activation instruction signal from said collision judgment means for activating said vehicle safety device; and

(e) deceleration compensation means for adjusting said trigger threshold level in accordance with the deceleration in such a manner that said trigger threshold level becomes lower when the deceleration is large and that said trigger threshold level becomes higher when the deceleration is small.

2. A control system according to claim 1, further comprising:

vehicle speed detecting means for detecting the speed of the vehicle, and

vehicle speed compensation means for varying the relation between said threshold level and the deceleration in accordance with a vehicle speed, detected by said vehicle speed detecting means, in such a manner that said threshold level becomes low when the vehicle speed is high and that said threshold level becomes high when the vehicle speed is low.

3. A control system according to claim 1, further comprising:

time measurement means for starting the measurement of an elapse time when said integral value reaches a predetermined level lower than said threshold level, and

time compensation means for varying the relation between said threshold level and the deceleration in accordance with said elapse time.

4. A control system for a vehicle safety device comprising:

(a) acceleration detecting means for detecting deceleration of a vehicle;

(b) integrating means for integrating the deceleration from said acceleration detecting means;

(c) collision judgment means for comparing an integral value, obtained by said integrating means, with a trigger threshold level to judge whether or not a collision has occurred, and for outputting an activation instruction signal when said collision judgment means judges that the collision has occurred;

(d) a drive circuit responsive to said activation instruction signal from said collision judgment means for activating said vehicle safety device;

(e) deceleration compensation means for adjusting said trigger threshold level in accordance with the deceleration in such a manner that said trigger threshold level becomes lower when the deceleration is large and that said trigger threshold level becomes higher when the deceleration is small; and

wherein

said control system is of the analog type,

said collision judgment means having two input terminals one of which receives an integral voltage, representative of the integral value of the deceleration, from said integrating means,

said deceleration compensation means including

a divider circuit having two resistor means serially connected together, one terminal of said divider circuit being connected to a constant voltage source whereas the other terminal thereof is connected to an output terminal of said acceleration detecting means, and

a voltage at a junction point between said two resistor means of said divider circuit being supplied, as a threshold voltage representative of said trigger threshold level, to the other input terminal of said collision judgment means, and

whereby said threshold voltage is linearly varied with respect to the output of said acceleration detecting means representative of the deceleration.

5. A control system according to claim 4, in which,

said acceleration detecting means outputs a reference voltage of a positive value when the vehicle is stopped or is running at a constant speed,

said acceleration detecting means outputting a voltage lower than said reference voltage when said vehicle is decelerated, said reference voltage being lower than a constant voltage fed from said constant voltage source, and

said integrating means inverting and integrating the output of said acceleration detecting means.

6. A control system according to claim 5, in which,

the output voltage of said acceleration detecting means is substantially zero volts when the deceleration is above a predetermined value, so that said threshold voltage is kept at a positive constant value.

7. A control system for a vehicle safety device comprising:

(a) acceleration detecting means for detecting deceleration of a vehicle;

(b) integrating means for integrating the deceleration from said acceleration detecting means;

(c) collision judgment means for comparing an integral value, obtained by said integrating means, with a trigger threshold level to judge whether or not a collision has occurred, and for outputting an activation instruction signal when said collision judgment means judges that the collision has occurred;

(d) a drive circuit responsive to said activation instruction signal from said collision judgment means for activating said vehicle safety device;

(e) deceleration compensation means for adjusting said trigger threshold level in accordance with the deceleration in such a manner that said trigger threshold level becomes lower when the deceleration is large and that said trigger threshold level becomes higher when the deceleration is small;

(f) vehicle speed detecting means for detecting the speed of the vehicle;

(g) vehicle speed compensation means for varying the relation between said trigger threshold level and the deceleration in accordance with a vehicle speed, detected by said vehicle speed detecting means, in such a manner that said trigger threshold level becomes lower when the vehicle speed is high and that said trigger threshold level becomes higher when the vehicle speed is low; and

(h) a microcomputer, said microcomputer including

said integrating means,

said collision judgment means,

said deceleration compensation means, and

said vehicle speed compensation means,

(g) a plurality of maps representative of the relation between the deceleration and said trigger threshold level being stored in said microcomputer, said plurality of maps including at least

a first map, and

a second map;

in each of said maps, said trigger threshold level being substantially linearly varied with respect to the deceleration in a first deceleration range in which the deceleration is below a specific value, said trigger threshold level being constant and its lower limit in a second deceleration range in which the deceleration is above said specific value, the variation of said trigger threshold level with respect to the deceleration in said first deceleration range being gentler in said first map than in said second map, the lower limit of said trigger threshold level being higher in said first map than in said second map, and said microcomputer selecting said first map when the vehicle speed is low, and selecting said second map when the vehicle speed is high.

8. A control system according to claim 7, in which,

said microcomputer further includes tire lock detecting means;

when a tire lock is detected by said tire lock detecting means, said microcomputer calculating the actual vehicle speed by gradually decreasing the vehicle speed, detected by said vehicle speed detecting means immediately before the detection of the tire lock, in accordance with an elapse time, and said microcomputer selecting one of said maps in accordance with said calculated vehicle speed.

9. A control system according to claim 8, in which said tire lock is detected base on an abrupt decrease of the detected vehicle speed.

10. A control system for a vehicle safety device comprising:

(a) acceleration detecting means for detecting deceleration of a vehicle;

(b) integrating means for integrating the deceleration from said acceleration detecting means;

(c) collision judgment means for comparing an integral value, obtained by said integrating means, with a trigger threshold level to judge whether or not a collision has occurred, and for outputting an activation instruction signal when said collision judgment means judges that the collision has occurred;

(d) a drive circuit responsive to said activation instruction signal from said collision judgment means for activating said vehicle safety device;

(e) deceleration compensation means for adjusting said trigger threshold level in accordance with the deceleration in such a manner that said trigger threshold level becomes lower when the deceleration is large and that said trigger threshold level becomes higher when the deceleration is small;

(f) time measurement means for starting the measurement of an elapse time when said integral value reaches a predetermined level lower than said trigger threshold level;

(g) time compensation means for varying the relation between said trigger threshold level and the deceleration in accordance with said elapse time; and

wherein

the relation between said trigger threshold level and the deceleration is varied in such a manner that said trigger threshold level is high when said elapse time is in a first time period, and that said trigger threshold level is low when said elapse time is in a second time period subsequent to said first time period, and that said trigger threshold level is high when said elapse time is in a third time period subsequent to said second time period.

11. A control system according to claim 10, in which there is provided:

a microcomputer, said microcomputer substantially including

said integrating means,

said collision judgment means,

said deceleration compensation means,

said time measurement means and said time compensation means,

a plurality of maps representative of the relation between the deceleration and said trigger threshold level being stored in said microcomputer, said plurality of maps including

a first map,

a second map and

a third map;

in each of said maps, said trigger threshold level being substantially linearly varied with respect to the deceleration in a first deceleration region in which the deceleration is below a specific value, said trigger threshold level being constant and its lower limit in a second deceleration region in which the deceleration is above said specific value, the variation of said trigger threshold level with respect to the deceleration in said first deceleration region being more abrupt in said second map than in said first and third maps, the lower limit of said trigger threshold level being lower in said second map than in said first and third maps, and said microcomputer selecting said first map when the measured time is in said first time period, and selecting said second map when the measured time is in said second time period, and selecting said third map when the measured time is in said third time period.

12. A control system according to claim 10, in which there is provided

a microcomputer, said microcomputer including

said integrating means,

said collision judgment means,

said deceleration compensation means,

said time measurement means, and

said time compensation means,

a map representative of the relation between the deceleration and said trigger threshold level being stored in said microcomputer, said microcomputer calculating a value by multiplying the deceleration by a gain, and applying this value as the deceleration to said map, thereby determining said trigger threshold level, said gain varying in accordance with the measured time;

and when said measured time is in said first time period, said gain being small, and when said measured time is in said second time period, said gain being large, and when said measured time is in said third time period, said gain is small.