Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
1998-11-12
2001-02-13
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C701S046000, C280S735000
Reexamination Certificate
active
06188940
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method and apparatus for optimizing firing time of an occupant restraint system, and more particularly to an advanced restraint system algorithm using occupant sensor inputs to modify firing time of an air bag.
BACKGROUND OF THE INVENTION
The objective of an advanced restraint system is to provide an optimal protection system for an occupant involved in a vehicle impact. Until now, the systems involved in the task of restraining an occupant have all worked independently without any feedback between systems. A popular design uses a seat belt system that is designed to do the majority of the work of restraining an occupant. An air bag is deployed based on a vehicle crash pulse generated during a crash, which is sensed by a crash sensor. Deployment occurs at 30 ms prior to the point at which a properly seated, properly positioned occupant is expected to have moved five inches (or 500 mm). The air bag provides a restraining force that supplements the seat belt restraint.
The ideal system would have the seat belt start restraining the occupant until a certain load limit is reached. At that point, the air bag would have been deployed by the crash sensor and be ready to provide a supplemental restraining force.
To accomplish this system objective, occupant sensors have been proposed that provide feedback to a control system independently of the crash sensor and prevent or augment deployment of the air bag restraint if the occupant is out of position. However, this does not incorporate the crash sensor into a control loop, but rather the control algorithms still fire the air bag based upon the vehicle-specific 5-30 rule for time to fire (TTF), as explained above, is the crash sensor and occupant sensor work independently.
The crash sensor accelerometer does not always provide an accurate estimate of the occupant's “free body motion”. Also, it is well known that crash algorithms use various integral methods to estimate occupant movement, but these estimates do not incorporate real time feedback of occupant position.
It is desirable to provide a system which more accurately determines the “free body motion” of the vehicle occupant so that the optimal firing time of the air bag can be more accurately determined.
DISCLOSURE OF THE INVENTION
The present invention overcomes the above-referenced shortcomings of prior systems by using the occupant position sensors to augment the crash sensor accelerometer firing decision. In order to make the system truly adaptive, and closed loop, the firing decision is based upon the sensed occupant position as a supplement to the crash sensor accelerometer signal. In this manner, the air bag will be provided at the exact time when the specific occupant requires it.
More specifically, the present invention provides a method for sensing the occurrence of a vehicle crash in a vehicle having an occupant restraint system operatively connected with a crash sensor having an accelerometer which produces an accelerometer signal (or crash signal), and with an occupant position sensor which produces a position signal. The crash sensor includes an adjustable filter. The method comprises the steps of:
A. Calculating an estimated occupant displacement by integrating the accelerometer signal twice;
B. Comparing the estimated occupant displacement to the position signal; and
C. Adjusting the adjustable filter based upon the comparing step so that the estimated occupant displacement closely correlates with the position signal, thereby optimizing control of the occupant restraint system.
An apparatus is also provided for controlling an occupant restraint system having an air bag, the apparatus including a crash sensor accelerometer for measuring vehicle deceleration and producing an accelerometer signal (or crash signal); an occupant position sensing system for measuring occupant position and producing a position signal; and a controller operatively connected to the crash sensor accelerometer and occupant position sensing system, wherein the controller incorporates an algorithm for determining an appropriate time to fire the air bag based upon the accelerometer and position signals.
Preferably, the step of adjusting the adjustable filter is performed such that lower frequencies of acceleration are twice integrated, which provides optimal firing of the air bag. In other words, the adjustment comprises using lower frequency high pass filter coefficients if the position signal leads the estimated occupant displacement, and using higher frequency high pass filter coefficients if the position signal lags the estimated occupant displacement.
Accordingly, an object of the invention is to use the occupant position sensor in conjunction with the crash sensor accelerometer to augment the occupant restraint firing system.
A further object of the invention is to create an adaptive, closed loop control system which adjusts a crash sensor filter based upon a comparison between the double integral of the crash sensor accelerometer and the occupant position sensor signal.
The above objects and other objects, features and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.
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patent: 6056079 (2000-05-01), Cech et al.
Blackburn Brian
Brown Joseph R.
Gentry Scott B.
Mazur Joseph F.
Cuchlinski Jr. William A.
Ford Global Technologies Inc.
Kelley David B.
Mancho Ronnie
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