Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
1998-12-22
2001-09-18
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C340S438000, C280S735000, C180S271000
Reexamination Certificate
active
06292727
ABSTRACT:
FIELD OF THE INVENTION
This invention relates systems for determining if a vehicle seat is occupied by a person and, if so, insuring that the air bag will protect the person during a collision as well as possible.
BACKGROUND OF THE INVENTION
An air bag comprises an inflatable bag and means for inflating the bag. Air bags are highly desired life saving devices that have performed well in many accidents and saved many lives. However, the bag must be inflated in a very brief time such as {fraction (1/30)} of a second which requires rapid movement of the bag from a stored and compacted state to a fully inflated state. The rapid deployment of the bag involves great force. A deploying bag can injure a person during the early phases of deployment if the person is very close to where the airbag is stored. Another hazardous circumstances is when the occupant is a baby in a rear-facing baby seat. It is also desired to inhibit deployment if there is no person in the seat. Much effort has gone into developing systems for characterizing the occupant and ascertaining the occupant position to meet this need. Proposed systems attempt to ascertain the distance from the inflator to the occupant and systems using sonic and optical ranging for that purpose are well known. These systems are deficient in that they cannot reliably distinguish between an occupant and other things such as road maps, beverage cups, packages and voluminous clothing which cause indications that the occupant is near the inflator. Known prior art systems operate to measure the distance from the inflator to the occupant, presumably because that is the physical variable most easily related to the potential for injury.
Many vehicles include an accelerometer located in the passenger compartment for sensing the deceleration of a crash. These accelerometers are incorporated in sensing and diagnostic modules or “SDM” which are decision making centers for the vehicle occupant protection system. The output of the accelerometer may be integrated by an analog circuit or a microprocessor in the SDM to compute a difference between the velocity the vehicle was traveling before a crash and the velocity of the passenger compartment during the crash. The integral of the accelerometer output may be integrated again to obtain the second integral of the deceleration which is the displacement of a free body from its initial position relative to the vehicle. An occupant not wearing a seat belt is, to a good approximation, a free body. Therefore, this calculation provides the distance an unbelted occupant has moved from his or her initial position at any time during the crash. Vehicles typically include seat belt latched sensors for indicating seat belt usage.
Position and angle sensors are in commercial production for sensing the position of a seat on its track and the angle the seat is reclined.
Capacitive proximity sensors have been well known for many years and have many successful applications. In addition to measuring capacitance, the Q of the capacitance may be used to provide additional information about the nature of the material being detected. Some materials including materials containing water tend to reduce the Q of the sensed capacitance.
Circuits for measuring capacitance and the Q of a capacitor are well known and are incorporated in many commercially available measuring instruments.
A general object of this invention is to provide an occupant position sensing means and associated decision making for automotive vehicles which also overcomes certain disadvantages of the prior art.
SUMMARY OF THE INVENTION
The present invention provides capacitor electrodes and means responsive to the capacitance between them to indicate the presence and position of a vehicle occupant that is highly reliable and economical to manufacture.
Further, in accordance with this invention, one capacitor electrode is placed in the back of a vehicle seat and a second capacitor electrode is placed in the seat cushion of a vehicle seat.
Further, in accordance with this invention, it is shown that identifying when air bags may or may not be safely and effectively deployed is in most circumstances equivalent to determining whether or not the seat is occupied by a person in a normal seated position.
Further, in accordance with this invention, it is ascertained that a seat is occupied by a person and a measurement is obtained of the distance from the back of the seat to the back of the person.
Further, in accordance with this invention, the position of a person is determined from the distance from the back of the seat to the back of the person. This is preferable to ascertaining the position of a person by measuring the position of the front of the person because it is unusual for there to be objects likely to affect capacitance between the back of the seat and the back of the person whereas a person is likely to place objects in front of himself or herself which confuse known measuring systems which are based on reflected sound or light.
Further, in accordance with this invention, a highly accurate seat occupant presence and position sensing system is provided because at most times when a vehicle is in motion people in seats are either seated normally or positioned where air bag deployment could be dangerous. Further, by identifying if a seat is occupied by a normally seated person or is vacant other important conditions such as forward or rearward facing child seats are also identified.
Further, in accordance with this invention, occupants that have moved into dangerous positions are detected. An occupant reaching forward to place or retrieve something on the dash may be dangerously close to the inflator for a short time. By determining that the back of the occupant is ten inches or more from the back of the seat this invention allows the air bag to be disabled to eliminate the risk of injury. Note that such events are so infrequent and of such short duration that disabling deployment of the air bag during such events leaves the occupant protected almost all of the time. The capacitive presence and position sensing system of the invention provides information about the distance the occupant is leaning forward that can be used to further refine the decision making prior to disabling or enabling deployment of the air bag.
Further, in accordance with this invention, occupants that remain in dangerous positions are detected. For example, a person might lean forward constantly. One reason a person might lean forward constantly is if the person is very short and needs to lean forward to see the road. Another possible reason is the need to see view the road near the front of the vehicle during snow or fog. A person stretching forward and upward to get a better view is particularly vulnerable to injury by a rearward deploying air bag. The capacitive presence and position sensing system of the invention provides information about the distance the occupant is leaning forward for use to prevent air bag deployment when the seat occupant is far from a normal position. Since no known system accurately determines the occupant presence and position and is not confused by extraneous objects a capacitive occupant presence and position sensing system is an improvement on the known art.
Further, in accordance with this invention, the capacitive presence and position sensing system may also measure the Q of the capacitances being sensed to thereby ascertain additional information about the occupant of the seat.
Further, in accordance with this invention, the capacitive presence and position sensing system may also provide information about the distance of the occupant from the normal position against the back of the seat to further enhance the determination of whether or not deployment is warranted.
The invention is responsive to the distance of the back of a seated occupant from the surface of the seat back. This may, for example, be used to prevent deployment of an airbag when the occupant is located too far forward of the seat back.
Further, in accordance with this invention, ce
Cuchlinski Jr. William A.
Pipala Edward
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