Vehicle safety system implementing algorithm for early sensing of high-speed full overlap crash events
A method for controlling an actuatable safety device for protecting an occupant of a vehicle includes sensing a left upfront vehicle acceleration via a left upfront sensor, sensing a middle upfront vehicle acceleration via a middle upfront sensor, and sensing a right upfront vehicle acceleration via a right upfront sensor. The method also includes sensing a central vehicle acceleration via a central airbag control unit. The method further includes determining the occurrence of a vehicle crash event in response to determining that each of the left, middle, and right upfront vehicle accelerations exceeds a predetermined magnitude and is phase shifted from the central vehicle acceleration.
1 . A method for controlling an actuatable safety device for protecting an occupant of a vehicle, the method comprising:
sensing a left upfront vehicle acceleration via a left upfront sensor mounted at a front-left corner of the vehicle;
sensing a middle upfront vehicle acceleration via a middle upfront sensor mounted at a front-middle location of the vehicle;
sensing a right upfront vehicle acceleration via a right upfront sensor mounted at a front-right corner of the vehicle;
sensing a central vehicle acceleration via a central airbag control unit; determining an averaged upfront acceleration (UFS_AMA) for each of the left, middle, and right upfront vehicle accelerations;
determining a vehicle displacement in a longitudinal vehicle direction (X_REL_DISP) based on the central vehicle acceleration;
implementing, for each upfront acceleration, an upfront discrimination metric that evaluates the averaged upfront acceleration (UFS_AMA) against the vehicle displacement in the longitudinal vehicle direction (X_REL_DISP);
applying for each upfront discrimination metric, a threshold having a portion of reduced magnitude configured to enhance detection of a phase shift between the upfront acceleration and the central vehicle acceleration, wherein the threshold comprises a V-shaped reduced magnitude portion;
determining an occurrence of a vehicle crash event in response to determining all three upfront discrimination metrics simultaneously crossing their respective thresholds, wherein the simultaneous crossing indicates that each of the left, middle, and right upfront vehicle accelerations exceeds a predetermined magnitude and is phase shifted from the central vehicle acceleration; and
actuating the actuatable safety device in response to determining the occurrence of the vehicle crash event.
2 . The method recited in claim 1 , wherein determining that each of the left, middle, and right upfront vehicle accelerations exceeds a predetermined magnitude and is phase shifted from the central vehicle acceleration comprises, for each upfront acceleration:
executing an upfront discrimination metric that evaluates an averaged upfront acceleration (UFS_AMA) and a vehicle displacement in a longitudinal vehicle direction (X_REL_DISP);
implementing in the upfront discrimination metric, a threshold configured to detect a phase shift between the averaged upfront acceleration and the central vehicle acceleration; and
determine a must-fire condition in response to the upfront discrimination metric crossing the threshold.
3 . The method recited in claim 2 , wherein the threshold of the upfront discrimination metric comprises a portion of reduced magnitude configured to enhance detection of the phase shift between the averaged upfront acceleration and the central vehicle acceleration.
4 . The method recited in claim 1 , wherein the vehicle crash event comprises a high-speed full overlap crash event.
5 . A vehicle safety system comprising:
an actuatable safety device;
a left upfront sensor;
a middle upfront sensor;
a right upfront sensor; and
a central airbag control unit comprising a controller configured to:
determine an averaged upfront acceleration (UFS_AMA) for each of the left, middle, and right upfront vehicle accelerations;
determine a vehicle displacement in a longitudinal vehicle direction (X_REL_DISP) based on the central vehicle acceleration;
implement, for each upfront acceleration, an upfront discrimination metric that evaluates the averaged upfront acceleration (UFS_AMA) against the vehicle displacement in the longitudinal vehicle direction (X_REL_DISP);
apply for each upfront discrimination metric, a threshold having a portion of reduced magnitude configured to enhance detection of a phase shift between the upfront acceleration and the central vehicle acceleration, wherein the threshold comprises a V-shaped reduced magnitude portion;
determine an occurrence of a vehicle crash event in response to determining all three upfront discrimination metrics simultaneously crossing their respective thresholds, wherein the simultaneous crossing indicates that each of the left, middle, and right upfront vehicle accelerations exceeds a predetermined magnitude and is phase shifted from the central vehicle acceleration; and
actuate the actuatable safety device in response to determining the occurrence of the vehicle crash event.
6 . A vehicle safety system comprising:
an actuatable safety device;
a left upfront sensor mounted at a front-left corner of the vehicle;
a middle upfront sensor mounted at a front-middle location of the vehicle;
a right upfront sensor mounted at a front-right corner of the vehicle; and
an airbag control unit (ACU) operatively connected to the actuatable safety device, the left upfront acceleration sensor, the middle upfront acceleration sensor, and the right upfront acceleration sensor;
wherein the airbag control unit comprises an airbag control unit acceleration sensor and a controller, the controller being configured to
determine an averaged upfront acceleration (UFS_AMA) for each of the left, middle, and right upfront vehicle accelerations;
determine a vehicle displacement in a longitudinal vehicle direction (X_REL_DISP) based on the central vehicle acceleration;
implement, for each upfront acceleration, an upfront discrimination metric that evaluates the averaged upfront acceleration (UFS_AMA) against the vehicle displacement in the longitudinal vehicle direction (X_REL_DISP);
apply for each upfront discrimination metric, a threshold having a portion of reduced magnitude configured to enhance detection of a phase shift between the upfront acceleration and the central vehicle acceleration, wherein the threshold comprises a V-shaped reduced magnitude portion;
determine an occurrence of a vehicle crash event in response to determining all three upfront discrimination metrics simultaneously crossing their respective thresholds, wherein the simultaneous crossing indicates that each of the left, middle, and right upfront vehicle accelerations exceeds a predetermined magnitude and is phase shifted from the central vehicle acceleration; and
actuate the actuatable safety device in response to determining the occurrence of the vehicle crash event.