Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/013—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting collisions, impending collisions or roll-over
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/013—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting collisions, impending collisions or roll-over
  • B60R21/0132—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting collisions, impending collisions or roll-over responsive to vehicle motion parameters, e.g. to vehicle longitudinal or transversal deceleration or speed value
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
  • B60R21/013—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting collisions, impending collisions or roll-over
  • B60R21/0134—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting collisions, impending collisions or roll-over responsive to imminent contact with an obstacle, e.g. using radar systems

Definitions

• THE PRESENT INVENTION relates to an arrangement for triggering a vehicle safety device such as, for example, an airbag or a pretensioner.
• the arming unit may comprise a simple acceleration sensor which generates the arming signal if the acceleration exceeds a predetermined level.
• the arming unit may include one or more sensors and a processing unit which performs a predetermined algorithm, the arming algorithm, on the signal or signals received from the or each sensor to provide the appropriate output.
• the crash unit may again comprise a simple acceleration sensor which generates a signal if the acceleration exceeds a predetermined level, but again the crash unit may comprise one or more sensors associated with a processor which is configured to perform an algorithm, the crash algorithm, on the signal or signals received from the or each sensor to provide the appropriate output.
• the crash unit typically includes a sensor which is directionally sensitive, the sensitive direction of the accelerometer being aligned with the crash direction which is to be sensed by the sensor.
• the crash algorithm may be determined by whether or not the acceleration sensed by the accelerometer, acceleration "a" or its integrated value, ⁇ v exceed a predetermined threshold.
• a proximity sensor configured to provide an output related to the distance to an object and/or the relative speed between the object and the sensor, such as a doppler radar, to improve the ability to discriminate between different potential crashes, so as, for example, to discriminate between a potentially dangerous crash and a potentially not dangerous crash. If a doppler radar is utilised, the output represents the relative speed v re i between the sensor and a nearby obstacle.
• the present invention seeks to provide an improved arrangement for triggering a vehicle safely device.
• an arrangement for triggering a vehicle safety device the arrangement incorporating a proximity sensor configured to provide an output related to the distance to an object and/or the relative speed between the object and the sensor, and an accelerometer, the arrangement further comprising a first processing arrangement to perform a crash algorithm on signals received from the proximity sensor and the accelerometer, and a second processing arrangement to perform an arming algorithm, on signals received from the proximity sensor and the accelerometer, the arrangement incorporating a signal generator to generate a signal in response to simultaneous output of a signal from the first processing arrangement and a signal from the second processing arrangement.
• the first processing arrangement and the second processing arrangement are constituted by separate hardware units.
• first processing arrangement and the second processing arrangement are constituted by discrete hardware components.
• first processing arrangement and the second processing arrangement are constituted by integrated circuits.
• first processing arrangement and the second processing arrangement are each mounted on a respective printed circuit board.
• first processing arrangement and the second processing arrangement are constituted by separate software controlled processors.
• the proximity sensor is a radar.
• the radar is a doppler radar.
• the accelerometer is sensitive to acceleration in a predetermined direction.
• the processing sensor is oriented to determine the distance in the said predetermined direction to an object.
• the arrangement is mounted in a vehicle, with the said predetermined direction of the accelerometer being aligned with the longitudinal axis of the vehicle.
• the arrangement may be mounted in a vehicle, with the said predetermined direction of the accelerometer being parallel with the lateral axis of the vehicle.
• the signal from the proximity sensor represents the relative velocity (v re i) between the sensor and an object.
• the signal from the accelerometer is a and the first processing unit produces an output when a exceeds a predetermined threshold and when the relative velocity v re i exceeds a separate predetermined threshold.
• the first processing unit which performs the arming algorithm produces an output when the sensed acceleration a exceeds a first predetermined threshold and is lower than a second predetermined threshold and when the sensed relative velocity v rel is greater than a first predetermined threshold and lower than a second predetermined threshold.
• the second processing arrangement which performs the crash algorithm compares a function of a and v re i (f(a,v re i) with a constant.
• the function of a and v re i is a function of a multiplied by a function of v re i so that
• acceleration and relative velocity is acceleration multiplied by the relative velocity raised to a power and divided by a time period over which acceleration and relative velocity are measured, so
• FIGURE 1 is a block diagram illustrating one embodiment of the invention.
• FIGURE 2 is a block diagram of a more detailed embodiment of the invention.
• an arrangement for triggering a vehicle safety device comprises a proximity sensor 1, which is configured to provide an output related to the distance to an object and/or the relative speed between the object and the sensor.
• the sensor may be an optical sensor or an ultrasonic sensor but in the preferred embodiment of the invention the proximity sensor is a radar sensor.
• a radar can provide an output related to the distance to an object sensed by the radar by measuring the time delay of the reflected pulse.
• a doppler radar is used to provide an output indicative of the relative speed between the object and the sensor, by using the doppler effect. The relative speed could also be provided by differentiating the distance.
• the arrangement of the invention also includes an accelerometer 2.
• the accelerometer is especially sensitive to acceleration in a predetermined direction, the accelerometer being oriented so that the said predetermined direction is aligned with the direction of a crash which is to be sensed.
• the accelerometer is oriented so that the said predetermined direction of the accelerometer is aligned with the longitudinal axis of the vehicle.
• the accelerometer will be located in position with the said direction aligned with the transverse axis of the vehicle.
• the arrangement of the invention also incorporates a first processing unit 3.
• the processing unit 3 is a unit which is programmed to perform a "crash" algorithm.
• the first processing unit 3 is connected to receive a signal from the proximity sensor 1 and is also connected to receive a signal from the accelerometer 2.
• the processing unit 3 has an output which is connected to an AND gate 4, the AND gate 4 having an output 5 which is the trigger signal to trigger the vehicle safety device.
• an AND gate is described, the AND function may be achieved in many different ways.
• a second processing unit 6 is also provided, the second processing unit 6 again being connected to receive a signal from the proximity sensor 1 and a signal from the accelerometer 2.
• the second processing unit 6 is a programmed unit which is programmed to perform an "arming" algorithm.
• the output from the unit 6 is connected to an input to the AND gate 4.
• the AND gate 4 will only produce the trigger signal 5 when it simultaneously receives signals from the first processing unit 3, which performs the arming algorithm, and the second processing unit 6, which performs the crash algorithm.
• crash algorithm and the arming algorithm and the AND function may be realised by separate hardware units as described, or by a single complex hardware unit. Each unit could comprise several discrete components or a single integrated circuit. Alternatively the functionality could be provided by a software controlled processor.
• the proximity sensor 1 is a doppler radar, the doppler radar producing an output signal v re i, indicative to the relative speed of an external object relative to the sensor in a predetermined direction, for objects within a predetermined distance of the sensor.
• the accelerometer 2 produces an output signal "a" representative of the acceleration of the sensor.
• the second processing unit 6 which performs the arming algorithm receives, consequently, the signals v re i and a.
• the signal v rel is initially compared with at least a first reference value V ⁇
• the comparison is effected by a comparator 7, but the comparison function may be performed in any way.
• the comparator will only provide an output if the input signal v re i is greater than the first predetermined value vl. In the described embodiment of the invention, however, the comparator 7 is more sophisticated and will only produce an output signal if v re i exceeds the first reference value vl but is less than a second reference value v2.
• the signal a from the accelerometer 2 is processed by a comparator 8, and the comparator 8 will only provide an output if the value a is greater than a first reference value a ⁇ .
• the comparison function may be performed in any way.
• the comparator is more sophisticated and will only produce an output if the signal a is greater than a first reference value al but less than a second reference value a 2 .
• the outputs of the two comparators 7,8 present within the first processing unit 3, are passed to an AND gate 9, the output of the AND gate 9 being the output of the first processing unit 3.
• the AND function may be preferred in any way.
• the second processing unit 6 which performs the arming algorithm will only produce an output signal when the relative velocity sensed by the doppler radar 1 is greater than a predetermined threshold and the acceleration sensed by the accelerometer is greater than a predetermined threshold but preferably only produces an output when the sensed relative velocity is greater than a first threshold value and lower than the second threshold value and also when the sensed acceleration is greater than a first threshold value and lower than a second threshold value.
• the first processor unit 3 which performs the crash algorithm, again receives the signals v rel from the doppler radar 1 and a from the accelerometer 2.
• the first processor unit 3 incorporates a comparator 10 which compares a function of relative velocity and acceleration (f(a,v re i) with a constant, only producing an output if the function exceeds the constant. Again, while a comparator is described the comparison function may be performed in any way.
• the function may be a function of acceleration multiplied by a function of relative velocity, thus :
• the function may be a more complicated function in which the signal for acceleration is multiplied by the relative velocity raised to a predetermined power, greater than zero divided by the period of time over which the acceleration and the relative velocity have been measured.
• t is the period of time over which acceleration and relative velocity are measured.
• first processing unit 3 and the second processing unit 6 are preferably formed in totally discrete and separate units, which may be separate software-controlled processors, or which may be separate hardware processing units 3, 6, which may, for example, each be mounted on its own separate printed circuit board. This is to minimise the risk of a single fault within a single processor, a single hardware unit or on a single printed circuit board leading to inadvertent failure.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Radar Systems Or Details Thereof (AREA)
• Air Bags (AREA)
• Portable Nailing Machines And Staplers (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (9)

Cited By (3)

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Citations (2)

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• 2004
  • 2004-06-30 GB GB0414675A patent/GB2415818B/en not_active Expired - Fee Related
• 2005
  • 2005-05-20 JP JP2007519150A patent/JP4794554B2/ja not_active Expired - Fee Related
  • 2005-05-20 CN CNB2005800222646A patent/CN100434311C/zh not_active Expired - Lifetime
  • 2005-05-20 EP EP05742570A patent/EP1761412B1/en not_active Expired - Lifetime
  • 2005-05-20 US US11/630,941 patent/US7912608B2/en active Active
  • 2005-05-20 KR KR1020077002335A patent/KR101187113B1/ko not_active Expired - Fee Related
  • 2005-05-20 WO PCT/SE2005/000742 patent/WO2006004475A1/en not_active Ceased
  • 2005-05-20 AT AT05742570T patent/ATE492436T1/de not_active IP Right Cessation
  • 2005-05-20 DE DE602005025481T patent/DE602005025481D1/de not_active Expired - Lifetime

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