Patent Application
20100179731
1. Technical Field
One or more embodiments of the present invention described herein generally relate to a system and method for performing vehicle side impact sensing with unit area impulse.
2. Background Art
The use of pressure sensors for detecting vehicle side impacts have been known for several years. In general, the pressure sensors are positioned within door cavities (i.e., between A and B pillars) of a vehicle. The vehicle is generally equipped with a controller that includes a pressure threshold stored therein. The controller monitors pressure signals transmitted from one or more of the pressure sensors to determine if such signals exceed the pressure threshold. If the measured pressure signals exceed the pressure threshold, such a condition may correspond to the vehicle experiencing a side impact. While pressure sensor technology has proven to be effective in detecting vehicle side impacts under certain conditions, the pressure value used to define the pressure threshold may trigger a false detection of a vehicle side impact.
A system for detecting impact events for a vehicle is provided. The system comprises a pressure sensor and a controller. The pressure sensor is positioned in a first impact zone of the vehicle and is configured to generate a pressure signal corresponding to a measured pressure reading within the first impact zone. The controller is positioned within the vehicle and is configured to integrate the pressure signal over time to determine the occurrence of a vehicle impact event at the first impact zone.
Embodiments of the present invention described herein are recited with particularity in the appended claims. However, other features will become more apparent, and the embodiments may be best understood by referring to the following detailed description in conjunction with the accompanying drawings, in which:
The embodiments of the present invention generally provide a controller being operably coupled to a plurality of pressure sensors for detecting the occurrence of a vehicle impact. The controller includes a pressure integral level threshold for comparison to integrated pressure signals to determine if a valid vehicle side impact has occurred. Prior to the controller comparing the integrated pressure signals to the pressure integral level threshold, the controller integrates pressure signals transmitted by the pressure sensors to generate the integrated pressure signals. The controller is also operably coupled to accelerometer sensors positioned about the vehicle. The controller monitors acceleration signals transmitted by the accelerometer sensors and compares such signals to at least one acceleration threshold to confirm that a vehicle impact has occurred while generating and comparing the integrated pressure signals to the pressure integral level threshold. In the event both the integrated pressure signals and the measured acceleration signals exceed the pressure integral level threshold and the acceleration threshold, respectively, the controller deploys one or more safety restraint systems within the vehicle.
Referring now to
In general, each pressure sensor 154 is positioned in a door well cavity of each zone 102 and 104 (or other suitable area in the vehicle). Each pressure sensor 154 is configured to measure pressure in each door cavity and to transmit a pressure signal corresponding to the measured amount of pressure for each door cavity in each corresponding zone 102 and 104 to the controller 152. The controller 152 monitors for pressure changes within each cavity of the zone 102 and 104 in response to the pressure signals transmitted from the pressure sensors 154 to determine whether the vehicle 100 is experiencing a side impact. In general, a pressure change in the door cavity of the vehicle 100 may be caused in response to the vehicle 100 experiencing a side impact. The controller 152 is configured to receive the pressure signals and to integrate the received pressure signals for comparison to at least one pressure integral level threshold to determine whether the vehicle has encountered a side impact. Prior to deploying one or more safety restraint systems in the vehicle 100 in the event the integrated pressure signals exceed the pressure integral level threshold, the controller 152 may validate the occurrence of a side impact at zones 102 and 104 by monitoring acceleration signals from the accelerometer sensors 156 and 156′.
Each accelerometer sensor 156 is coupled to a structural member positioned within each zone 106 and 108. Each accelerometer sensor 156 is configured to transmit a first acceleration signal to the controller 152. The first acceleration signal corresponds to the measured movement of the structural member(s) within zones 106 and 108 in the event the vehicle 100 experiences an impact. As noted above, the controller 152 also includes an accelerometer sensor 156′ positioned therein or about the controller 152. The accelerometer sensor 156′ generates a second acceleration signal that corresponds to the measured movement of structural member(s) about the center of the vehicle. The controller 152 monitors the first acceleration signals received by the accelerometer sensor 156 and the second acceleration signals received from the accelerometer sensor 156′ and compares such signals to at least one acceleration threshold to validate (or confirm) that the vehicle 100 has experienced a side impact. For example, the comparison of the acceleration signals to the acceleration threshold may serve as a mechanism to validate that a side impact collision has occurred at zones 102 and 104.
In general, the controller 152 integrates the pressure signals and compares such signals to the pressure integral level threshold and also receives the acceleration signals and compares such signals to the acceleration threshold to confirm that the vehicle 100 has encountered a side impact. In the event both the integrated pressure signals and the acceleration signals exceed the pressure integral level threshold and the acceleration threshold, respectively, the controller 152 controls various restraint systems to deploy. Such restraint systems may include, but are not limited to, curtain and/or side airbags (not shown).
Referring now to
Waveform 204 corresponds to pressure readings (or pressure signals) that may be exhibited by the pressure sensors with respect to time while the vehicle 100 is undergoing an 18 mph perpendicular pole (PP) vehicle side impact test. The 18 mph PP test is representative of medium intensity level side impacts that may also require side airbag and curtain airbag deployment. Waveform 206 corresponds to pressure readings (or pressure signals) that may be exhibited by the pressure sensors with respect to time while the vehicle 100 is undergoing a 12 mph PP vehicle side impact test. The 12 mph PP test is representative of low intensity level side impacts that may require side airbag and curtain airbag deployment. Waveform 208 corresponds to pressure readings (pressure signals) that may be exhibited by the pressure sensor with respect to time while the vehicle 100 is undergoing a 12 mph side impact Cart test. The 12 mph side impact CART test may be performed with a NHTSA side impactor with a moving deformable barrier traveling at 12 mph and at an angle of roughly 27 degrees with respect to the side of the vehicle. It is generally not desired to deploy restraints when such a test is performed.
Line 210 corresponds to a first pressure threshold (e.g., 50 mbar) that may be used to distinguish between side and curtain airbag deployment and non-deployment events during a side impact event. The use of 50 mbar for the first pressure threshold serves as an example and it is recognized that the first pressure threshold may be set to any pressure value as needed based on the desired criteria of a particular implementation. As exhibited in
Referring now to
Waveform 304 corresponds to pressure readings (or pressure signals) that may be exhibited with respect to time by the pressure sensor 154 while the vehicle 100 is undergoing a 12 mph Cart test. Waveform 304 is similar to waveform 208 of
To obviate such a condition from occurring, the controller 152 may integrate the pressure readings received by the pressure sensors 154 to clearly separate restraint system deploy and non-deploy events during a side impact condition as detailed in
The pressure integral level threshold selected to separate low intensity impact deploy and non-deploy events also covers restraint system deploy requirements for medium and high intensity level side impact events. Further, the controller 152 may integrate pressure signals received from pressure sensors positioned in zones 106 and 108 and/or from pressure sensors positioned in the front and/or rear of the vehicle 100. As such, the integrated pressure signals received from pressure sensors positioned from those corresponding areas may be used to determine deployable or non-deployable events at the zones 106 and/or 108 and/or at the front and/or rear of the vehicle 100.
Referring now to
In operation 502, the controller 152 stores the pressure integral level threshold corresponding to a side impact level. In operation 504, the controller 152 stores acceleration thresholds that may be used for comparison to received acceleration signals for deployment validation purposes.
In operation 506, the controller 152 receives the pressure signals from the pressure sensors 154 positioned in zones 102 and 104.
In operation 508, the controller 152 determines the unit area impulse (UAI) for the measured pressure readings received from the pressure sensors 154 to generate the integrated pressure signals. The following equation below may be used to determine the UAI:
UAI=∫t2t1P·dt EQ.1
where P corresponds to the measure pressure readings (or signals), t1 and t2 corresponds to a moving window of time (e.g., 10 msec to 40 msec) (see
In operation 510, the controller 152 receives acceleration signals from the accelerometer sensors 156 positioned in zones 106 and 108 and from the accelerometer sensor 156′ positioned within or about the controller 152.
In operation 512, the controller 152 determines whether the integrated pressure signals are greater than the pressure integral level threshold. In the event the controller 152 determines that the integrated pressure signals are not greater than the pressure integral level threshold, the method 500 moves back to operation 506. In the event the controller 152 determines that the integrated pressure signals are greater than the pressure integral level threshold, the method 500 moves to operation 514.
In operation 514, the controller 152 compares the measured acceleration signals received from the accelerometer sensors 156 and 156′ to the acceleration thresholds. In the event the controller 152 determines that the acceleration signals are not greater than the acceleration thresholds, the method 500 moves back to operation 506. In the event the controller 152 determines that the acceleration signals are greater than the acceleration thresholds, the method 500 moves to operation 516.
In operation 516, the controller 152 deploys side impact restraint systems to protect occupants in the vehicle 100. Such restraint systems may include curtain, side airbags and/or deployable side bolsters or other suitable side impact protection systems.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and various changes may be made without departing from the spirit and scope of the invention.
