Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
1998-05-18
2001-02-20
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C180S271000, C180S282000, C280S735000
Reexamination Certificate
active
06192305
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to rollover sensors and, more particularly, to low-cost vehicle rollover sensors for sensing a rollover or pitchover condition of a vehicle.
Future generation automotive vehicles may increasingly employ safety-related devices that deploy in the event that the vehicle rolls over to provide added protection to the occupants of the vehicle. For example, upon detecting a vehicle rollover condition, a pop-up roll bar can be deployed such that, when activated, the roll bar further extends vertically outward to increase the height of support provided by the roll bar. Other controllable features may include actuating deployment of one or more air bags, such as front or side deployment air bags, or actuating a pretensioner to pretension a restraining device, such as a seat belt or safety harness, to prevent occupants of the vehicle from ejecting from the vehicle or colliding with the roof of the vehicle.
In the past, basic rollover sensors have been employed in automotive vehicles to measure the angular position of the vehicle from which a rollover condition can be determined. The basic rollover sensors have included the use of a pendulum normally hanging vertically downward due to the earth's gravitational force. Many basic automotive sensing devices are employed simply to monitor the angular position of the vehicle relative to a level ground horizontal position. As a consequence, the basic automotive vehicle rollover sensors have generally been susceptible to error when the vehicle travels around a turn or becomes airborne, in which case the earth's gravitational force, which the sensor relies on, may be overcome by other forces.
More recently, sophisticated rollover sensing approaches have been considered. One such approach considered requires the use of six sensors including three accelerometers and three angular rate sensors, also referred to as gyros, all of which are employed together for use in an inertial navigation system which tracks position and attitude of the vehicle. The three accelerometers generally provide lateral, longitudinal, and vertical acceleration measurements of the vehicle, while the three gyros measure pitch rate, roll rate, and yaw rate. However, the more sophisticated rollover sensing approaches generally require a large number of high-precision and expensive sensors. In addition, known sophisticated systems are susceptible to cumulative drift errors, and therefore must be reset occasionally.
It is, therefore, one object of the present invention to provide for vehicle rollover and pitchover sensing that requires minimal sensed measurement parameters and is relatively immune to errors generally found in conventional automotive-grade sensors. It is another object of the present invention to provide for vehicle rollover sensing for an automotive vehicle that may predict a future rollover condition in advance to allow time to deploy occupant protection measures. It is a further object of the present invention to provide for reliable vehicle rollover sensing in a low-cost sensing module. Yet, it is also another object of the present invention to achieve vehicle rollover sensing that corrects signal measurements to correct for errors caused by the vehicle experiencing yaw rate.
SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention, a vehicle rollover sensing apparatus and method are provided for predicting an overturn condition of a vehicle. The apparatus includes an angular roll rate sensor for sensing roll rate of the vehicle and an angular pitch rate sensor for sensing pitch rate of the vehicle. The apparatus also includes a longitudinal accelerometer for measuring longitudinal acceleration of the vehicle, a lateral accelerometer for measuring lateral acceleration of the vehicle, and a vertical accelerometer for measuring vertical acceleration of the vehicle. The apparatus further receives a vehicle speed signal indicative of speed of the vehicle. A processor receives the signals and estimates a roll angle and a pitch angle as a function of the received signals. The processor estimates a yaw rate of the vehicle as a function of lateral acceleration and vehicle speed and determines a pitch rate correction value as a function of the estimated yaw rate and the estimated roll angle and further corrects the measured pitch rate signal based on the pitch correction value. The processor also predicts a future pitch angle as a function of the estimated pitch angle and the corrected pitch rate and compares the predicted pitch angle to a threshold value. An output is provided for deploying a vehicle overturn condition based on the comparison.
In addition or alternately, the processor determines a roll rate correction value as a function of the estimated yaw rate and the estimated pitch angle and corrects the measured roll rate signal based on the roll correction value. The processor further predicts a future roll angle as a function of the estimated roll angle and the corrected roll rate and compares the predicted roll angle to a threshold value to predict a rollover condition of the vehicle. An output is provided for deploying a vehicle overturn condition based on the comparison.
A method is also provided for predicting an overturn condition of a vehicle. The method includes sensing angular roll rate and angular pitch rate of a vehicle. The method further senses longitudinal acceleration, lateral acceleration, and vertical acceleration of the vehicle. The method further receives a vehicle speed signal indicative of speed of the vehicle. A roll angle and pitch angle are estimated as a function of the received signals, and a yaw rate of the vehicle is estimated as a function of lateral acceleration and the vehicle speed signal. The method further determines a pitch rate correction value as a function of the estimated yaw rate and the estimated roll angle and corrects the measured pitch rate signal based on the pitch corrected value. A future pitch angle is predicted as a function of the estimated pitch angle and corrected pitch rate and compared to a threshold value. The method deploys a vehicle overturn condition output based on the comparison step.
In addition or alternately, the method determines a roll correction value as a function of the estimated yaw rate and the estimated pitch angle and corrects the measured roll rate signal based on the roll correction value. The method further includes the steps of predicting a future roll angle as a function of the estimated roll angle and the corrected roll rate and comparing the predicted roll angle to a roll threshold value and deploying an output based on the roll comparison.
These and other features, objects, and benefits of the invention will be recognized by those who practice the invention and by those skilled in the art, from reading the following specification and claims, together with reference to the accompanying drawings.
REFERENCES:
patent: 5610575 (1997-03-01), Gioutsos
patent: 5825284 (1998-10-01), Dunwoody et al.
patent: 5890084 (1999-03-01), Halasz et al.
Cuchlinski Jr. William A.
Delco Electronics Corporation
Funke Jimmy L.
Pipala Edward
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