Method for calibrating a single point impact sensor
First Claim
1. A method for calibrating an impact sensor that controls the activation of a passenger restraint mechanism in a vehicle, the method comprising the steps of:
- providing, within the sensor, a sense element that is responsive to acceleration, means for generating an electrical signal having a value that is a function of the sense element response, and an activation decision circuit having a counter means for determining if the electrical signal is indicative of a passenger restraint activation worthy event;
applying an acceleration to the sense element between a rate of zero acceleration and a full scale acceleration;
incrementally adjusting the acceleration applied to the sense element;
programming the generating means to adjust the value of the electrical signal within a predetermined range for each incremental acceleration value; and
verifying the calibration of the impact sensor.
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Accused Products
Abstract
A method for calibrating an impact sensor enables calibration to take place after sensor manufacture is completed. During calibration, the sensor undergoes an acceleration while vehicle specific calibration values are programmed into sensor memory for different incremental rates of acceleration. Calibration verification checks to verify that the relationship between acceleration and sensor output is linear. The calibration also includes a hysteresis test by comparing output values when incrementally increasing the acceleration to corresponding acceleration values while incrementally decreasing acceleration. The calibration method may also include calculating a response time for a self-test circuit that can be stored in memory and later used during self-tests of the sensor.
19 Citations
18 Claims
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1. A method for calibrating an impact sensor that controls the activation of a passenger restraint mechanism in a vehicle, the method comprising the steps of:
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providing, within the sensor, a sense element that is responsive to acceleration, means for generating an electrical signal having a value that is a function of the sense element response, and an activation decision circuit having a counter means for determining if the electrical signal is indicative of a passenger restraint activation worthy event; applying an acceleration to the sense element between a rate of zero acceleration and a full scale acceleration; incrementally adjusting the acceleration applied to the sense element; programming the generating means to adjust the value of the electrical signal within a predetermined range for each incremental acceleration value; and verifying the calibration of the impact sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for calibrating an impact sensor that controls the activation of a passenger restraint mechanism in a vehicle, the method comprising the steps of:
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providing, within the sensor, a sense element that is responsive to acceleration, means for generating an electrical signal having a pulse density which is a function of the sense element response, and an activation decision circuit having a counter for determining if the electrical signal is indicative of a passenger restraint activation worthy event; applying an acceleration to the sense element between a rate of zero acceleration and full scale acceleration; incrementally adjusting the acceleration applied to the sense element; programming the generating means to adjust the pulse density of the electrical signal within a predetermined range for each incremental acceleration value; and verifying the calibration of the impact sensor. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification