Crash detector responsive to a side impact
First Claim
1. A crash detector for activating a safety device in a vehicle in response to a side impact comprising:
- an accelerometer mounted on the door or on part of the monocoque shell of the vehicle adjacent the door, the accelerometer providing an acceleration signal indicative of the magnitude of the lateral acceleration to which the accelerometer is exposed and the direction of sensed acceleration relative to the centre-line of the vehicle where the acceleration signal increases with increasing inward acceleration; and
means for processing the acceleration signal from the accelerometer to generate a control signal, said processing means altering the value of the control signal, where at least a major component of the alteration is an increase in the value of the control signal or an adjustment of the value of the control signal to make the control signal converge to at least an average of the acceleration signal from the accelerometer during periods of time in which the acceleration signal from the accelerometer indicates an inward acceleration in excess of a predetermined level of acceleration, and where at least a major component of the alteration is a reduction of the value of the control signal, by a substantially predetermined amount during successive periods of time when the acceleration signal from the accelerometer is indicative of inward acceleration which is less than said predetermined level, the control signal being passed to threshold means enabling actuation of the safety device only when the threshold has been exceeded.
1 Assignment
0 Petitions
Accused Products
Abstract
A crash detector activates a safety device (3, 4) such as an air-bag in a vehicle. The crash detector incorporates an acceleration sensor (10), the output of which must pass a threshold (11) before the signal is processed by a signal processor (2). The signal is processed optionally in conventional ways (13, 14; 16, 17) to activate the safety device. Activation of the safety device is inhibited by a slam algorithm generator (18). In the slam algorithm generator a control signal is generated which converges towards an average of the acceleration signal during periods of time in which the acceleration signal indicates an inward acceleration in excess of a predetermined level, the control signal being reduced at a substantially constant rate with time during periods in which the acceleration is not in excess of said predetermined level. The control signal is passed to a threshold means (19) which enables (15) actuation of the safety device (3, 4).
31 Citations
21 Claims
-
1. A crash detector for activating a safety device in a vehicle in response to a side impact comprising:
-
an accelerometer mounted on the door or on part of the monocoque shell of the vehicle adjacent the door, the accelerometer providing an acceleration signal indicative of the magnitude of the lateral acceleration to which the accelerometer is exposed and the direction of sensed acceleration relative to the centre-line of the vehicle where the acceleration signal increases with increasing inward acceleration; and means for processing the acceleration signal from the accelerometer to generate a control signal, said processing means altering the value of the control signal, where at least a major component of the alteration is an increase in the value of the control signal or an adjustment of the value of the control signal to make the control signal converge to at least an average of the acceleration signal from the accelerometer during periods of time in which the acceleration signal from the accelerometer indicates an inward acceleration in excess of a predetermined level of acceleration, and where at least a major component of the alteration is a reduction of the value of the control signal, by a substantially predetermined amount during successive periods of time when the acceleration signal from the accelerometer is indicative of inward acceleration which is less than said predetermined level, the control signal being passed to threshold means enabling actuation of the safety device only when the threshold has been exceeded. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. A crash detector for activating a safety device in a vehicle in response to a side impact comprising:
-
an accelerometer mounted on the door or on part of the monocoque shell of the vehicle adjacent the door, the accelerometer providing an acceleration signal indicative of the magnitude of the lateral acceleration to which the accelerometer is exposed, and the direction of sensed acceleration relative to the centre-line of the vehicle where the acceleration signal increases with increasing inward acceleration; and means for processing the acceleration signal from the accelerometer to generate a control signal, said processing means altering the value of the control signal, where at least a major component of the alteration is an increase in the value of the control signal or an adjustment of the value of the control signal to make the control signal converge to at least an average of the acceleration signal from the accelerometer during periods of time in which the acceleration signal from the accelerometer indicates an inward acceleration in excess of a predetermined level of acceleration, and where at least a major component of the alteration is a reduction of the value of the control signal, by a substantially predetermined amount during successive periods of time when the acceleration signal from the accelerometer is indicative of inward acceleration which is less than said predetermined level, the control signal being passed to threshold means enabling actuation of the safety device only when the threshold has been exceeded; wherein during each period of time that the output signal from the accelerometer is indicative of less than the predetermined level acceleration, the control signal is adjusted, to a reduced value.
-
-
21. A crash detector for activating a safety device in a vehicle in response to a side impact comprising:
-
an accelerometer mounted on the door or on part of the monocoque shell of the vehicle adjacent the door, the accelerometer providing an acceleration signal indicative of the magnitude of the lateral acceleration to which the accelerometer is exposed, and the direction of sensed acceleration relative to the centre-line of the vehicle where the acceleration signal increases with increasing inward acceleration; and means for processing the acceleration signal from the accelerometer to generate a control signal, said processing means altering the value of the control signal, where at least a major component of the alteration is an increase in the value of the control signal or an adjustment of the value of the control signal to make the control signal converge to at least an average of the acceleration signal from the accelerometer during periods of time in which the acceleration signal from the accelerometer indicates an inward acceleration in excess of a predetermined level of acceleration, and where at least a major component of the alteration is a reduction of the value of the control signal, by a substantially predetermined amount during successive periods of time when the acceleration signal from the accelerometer is indicative of inward acceleration which is less than said predetermined level, the control signal being passed to threshold means enabling actuation of the safety device only when the threshold has been exceeded; wherein during each period of time that the output signal from the accelerometer is indicative of less than the predetermined level acceleration, the control signal is adjusted, to a reduced value by subtracting a constant value from the value of the control signal during the preceding period of time.
-
Specification