Vehicle airbag firing control system and airbag firing control method using the same
11084441 · 2021-08-10
Assignee
Inventors
Cpc classification
B60R21/0136
PERFORMING OPERATIONS; TRANSPORTING
B60W50/0098
PERFORMING OPERATIONS; TRANSPORTING
International classification
B60R21/0132
PERFORMING OPERATIONS; TRANSPORTING
B60R21/0136
PERFORMING OPERATIONS; TRANSPORTING
Abstract
An airbag firing control system may include an inertial measurement unit (IMU) including a low gravity (G) sensor configured to detect a longitudinal acceleration (ax), a filter configured to convert a first signal detection range of the low G sensor into a second signal detection range and to filter converted output of the low G sensor to generate a first output signal, and an adjuster configured to perform zero-point adjustment on the first output signal transmitted through the filter, and a microcomputer configured to use the first output signal for firing safing when the first output signal satisfies a safing condition as a performing result of the adjuster.
Claims
1. An airbag firing control system of a vehicle, the system comprising: an inertial measurement unit (IMU) including a low gravity (G) sensor configured to detect a longitudinal acceleration (ax) of the vehicle; a filter configured to filter an output signal of the low G sensor to convert a first signal detection range of the low G sensor into a second signal detection range; an adjuster configured to adjust a zero-point offset on an output signal of the filter; and a microcomputer configured to use an output signal of the adjuster for firing safing when the zero-point offset adjustment is completely performed within a first predetermined time, wherein the inertial measurement unit (IMU) further includes a first low pass filter (LPF) for low-filtering on the output signal of the low G sensor in a first frequency band, wherein the filter includes a converter for performing conversion of the first signal detection range into the second signal detection range wider than the first signal detection range by re-mapping raw data of the output signal of the low G sensor and a second low pass filter (LPF) for low-filtering on the output signal of the low G sensor in a second frequency band, wherein the second frequency band of the second low pass filter (LPF) is higher than the first frequency band of the first low pass filter (LPF), wherein a first signal having the first frequency band outputted through the first low pass filter (LPF) is transmitted to a signal processor of the inertial measurement unit (IMU), wherein a second signal having the second frequency band outputted through the second low pass filter (LPF) is transmitted to the adjuster, and wherein when a processing delay time of the output signal of the adjuster for firing safing is within a second predetermined time, the microcomputer determines whether an airbag is deployed based on the output signal of the adjuster for firing safing.
2. The system according to claim 1, wherein the first signal detection range is −5 to +5 g; and wherein the second signal detection range is −30 to +30 g.
3. The system according to claim 1, wherein the second frequency band is equal to or less than 400 Hz.
4. The system according to claim 1, wherein the adjuster includes an offset cancellation module using software or a zero-point adjustment algorithm for adjusting the zero-point offset on the output signal of the filter.
5. The system according to claim 1, wherein the output signal of the adjuster is used for firing safing when the zero-point adjustment is completely performed within 2 ms by the adjuster.
6. The system according to claim 1, further including a front impact sensor (FIS) disposed in the vehicle, wherein, when the zero-point adjustment is not completely performed within the first predetermined time by the adjuster or the low G sensor malfunctions, a detection signal of the FIS is used for firing safing.
7. The system according to claim 6, wherein the FIS includes a first sensor and a second sensor; and wherein the microcomputer utilizes a detection signal of a sensor that sends a first input signal among the first and second sensors when a crash occurs, for firing safing among sensors of the FIS.
8. An airbag firing control system of a vehicle, the system comprising: a main impact sensor configured to detect a crash of the vehicle; a microcomputer configured to determine whether the crash occurs according to a signal detected by the main impact sensor and to control firing of an airbag; an inertial measurement unit (IMU) including a low gravity (G) sensor configured to detect a longitudinal acceleration (ax) of the vehicle; a filter configured to filter an output signal of the low G sensor to convert a first signal detection range of the low G sensor into a second signal detection range; an adjuster configured to adjust zero-point offset on an output signal of the filter; a front impact sensor (FIS) disposed in the vehicle, wherein the microcomputer utilizes an output signal of the adjuster for firing safing when the zero-point offset adjustment is completely performed within a first predetermined time by the adjuster and utilizes an output signal of the FIS for safing when the zero-point offset adjustment is not completely performed within the first predetermined time by the adjuster, wherein the inertial measurement unit (IMU) further includes a first low pass filter (LPF) for low-filtering on the output signal of the low G sensor in a first frequency band, wherein the filter includes a converter for performing conversion of the first signal detection range into the second signal detection range wider than the first signal detection range by re-mapping raw data of the output signal of the low G sensor and a second low pass filter (LPF) for low-filtering on the output signal of the low G sensor in a second frequency band, wherein the second frequency band of the second low pass filter (LPF) is higher than the first frequency band of the first low pass filter (LPF), wherein a first signal having the first frequency band outputted through the first low pass filter (LPF) is transmitted to a signal processor of the inertial measurement unit (IMU), wherein a second signal having the second frequency band outputted through the second low pass filter (LPF) is transmitted to the adjuster, and wherein when a processing delay time of the output signal of the adjuster for firing safing is within a second predetermined time, the microcomputer determines whether an airbag is deployed based on the output signal of the adjuster for firing safing.
9. The system according to claim 8, wherein the FIS includes a first sensor and a second sensor; and wherein the microcomputer utilizes a detection signal of a sensor that sends the first input signal among the first and second sensors when the crash occurs, for firing safing among sensors of the FIS.
10. An airbag firing control method of a vehicle including a main impact sensor, a microcomputer, an inertial measurement unit (IMU) having a low gravity (G) sensor, a filter and an adjuster, the method comprising: detecting a crash by the main impact sensor; determining whether the crash occurs based on a crash signal detected by the main impact sensor; filtering an output signal of the low G sensor to convert a first signal detection range of the low G sensor into a second signal detection range through the filter; adjusting zero-point offset on an output signal of the filter through the adjuster; and determining whether the zero-point offset adjustment is completely performed within a first predetermined time by the microcomputer; and using an output signal of the adjuster for firing safing when the zero-point offset adjustment is completely performed within the first predetermined time, wherein the inertial measurement unit (IMU) includes a first low pass filter (LPF) for low-filtering on the output signal of the low G sensor in a first frequency band, wherein the filter includes a converter for performing conversion of the first signal detection range into the second signal detection range wider than the first signal detection range and a second low pass filter (LPF) for low-filtering on the output signal of the low G sensor in a second frequency band, wherein the second frequency band of the second low pass filter (LPF) is higher than the first frequency band of the first low pass filter (LPF), wherein a first signal having the first frequency band outputted through the first low pass filter (LPF) is transmitted to a signal processor of the inertial measurement unit (IMU), wherein a second signal having the second frequency band outputted through the second low pass filter (LPF) is transmitted to the adjuster, and wherein when a processing delay time of the output signal of the adjuster for firing safing is within a second predetermined time, the microcomputer determines whether an airbag is deployed based on the output signal of the adjuster for firing safing.
11. The method according to claim 10, wherein the first signal detection range is −5 to +5 g; and wherein the second signal detection range is −30 to +30 g.
12. The method according to claim 10, wherein the second frequency band is equal to or less than 400 Hz.
13. The method according to claim 10, wherein the adjusting zero-point offset is performed by an offset cancellation module using software or a zero-point adjustment algorithm.
14. The method according to claim 10, wherein the output signal of the adjuster is used for firing safing when the zero-point offset adjustment is completely performed within the first predetermined time.
15. The method according to claim 14, wherein the first predetermined time is 2 ms.
16. The method according to claim 10, further including: performing auxiliary safing using a detection signal of a front impact sensor (FIS) for safing when the zero-point adjustment is not completely performed or the low G sensor malfunctions in the determining whether the zero-point offset adjustment is completely performed.
17. The method according to claim 16, wherein the FIS includes at least one of a first sensor and a second sensor; and wherein a detection signal of a sensor that sends the first input signal among the first and second sensors when the crash occurs, is used for firing safing among sensors of the FIS.
18. The method according to claim 17, wherein the performing of the auxiliary safing further includes determining whether the detection signal of the FIS satisfies a safing condition.
19. The method according to claim 18, wherein the output signal of the adjuster is used for safing when the safing condition is satisfied during the auxiliary safing.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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(5) It may be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the present invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particularly intended application and use environment.
(6) In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.
DETAILED DESCRIPTION
(7) Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the present invention(s) will be described in conjunction with exemplary embodiments of the present invention, it will be understood that the present description is not intended to limit the present invention(s) to those exemplary embodiments. On the contrary, the present invention(s) is/are intended to cover not only the exemplary embodiments of the present invention, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the present invention as defined by the appended claims.
(8) Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
(9) Elements in the following drawings may be exaggerated, omitted, or schematically illustrated for conveniences and clarity of explanation, and the sizes of elements do not reflect their actual sizes completely. Like reference numerals in the drawings denote like elements. In a detailed description of exemplary embodiments of the present invention, the X axis indicates a progress direction (front direction) of a vehicle, the Y axis indicates a direction (lateral direction) orthogonal to the X axis, and the Z axis indicates a direction orthogonal to the XY plane.
(10) Hereinafter, an airbag firing control system of a vehicle according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.
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(12) As illustrated in
(13) Hereinafter, for convenience of description, the microcomputer 200 will be exchangeably used with a controller or a control device.
(14) Here, the ACU 100 may include the aforementioned microcomputer 200, the main impact sensor 300, the IMU 400, the filter 500, the adjuster 600, and so on.
(15) The ACU 100 may perform an integration function of detecting collision, determining collision, and transmitting a firing signal to a firing device of an inflator. That is, the ACU 100 may receive impact information detected by the main impact sensor 300, determine whether an airbag is to be deployed, and issue a deployment command according to the determination result. The ACU 100 may use the MU 400 as a sating sensor, which will be described below.
(16) The microcomputer 200 may receive information from various sensors, determine the information, and perform a logic of airbag firing. For example, the microcomputer 200 may lastly determine whether an airbag is ignited based on output of the main impact sensor 300 and the IMU 400 used as a safing sensor and may control whether the airbag is ignited according to the determination result. The microcomputer 200 controls whether the airbag is ignited. The microcomputer 200 may be referred to as a controller.
(17) The main impact sensor 300 may be disposed in the ACU 100 to detect a vehicle collision state. That is, the main impact sensor 300 may determine an acceleration and deceleration value (G value). The main impact sensor 300 may detect x-axis acceleration and y-axis acceleration of a vehicle at normal driving and rapid acceleration to output a sensor value of an electrical signal, and transmit the sensor value to the microcomputer 200.
(18) The sensor value of the main impact sensor 300 may be classified into ACU X as an X-axis sensor value of a vehicle and ACU Y as a Y-axis value. Accordingly, the main impact sensor 300 may also be referred as an ACU main sensor.
(19) The microcomputer 200 may compare the ACU X sensor value and a predetermined X-axis threshold value and compare the ACU Y sensor value and a predetermined Y-axis threshold value. As the comparison result, when the ACU X sensor value is equal to or greater than the X-axis threshold value or the ACU Y sensor value is equal to or greater than the Y-axis threshold value, the microcomputer 200 may lastly determine whether an airbag is deployed based on a comparison result value and a result value of the safing sensor.
(20) The IMU 400 may be included in the ACU 100 and may include a gravity sensor for measuring gravitational acceleration in X and Y-axis directions and a yaw rate sensor for measuring a yaw rate (rotational acceleration) in a z-axis direction, which is a separate element.
(21) The gravity sensor included in the IMU 400 according to the present embodiment may be a low G sensor 410 for measuring acceleration in X and Y-axis directions of a vehicle. The low G sensor 410 may have excellent performance for measuring low force such as impact, vibration, inclination, movement, or acceleration.
(22) An electronic stability control system (ESC) 900 may be a device configured for stabilizing a vehicle position and may control the vehicle position using information measured by the low G sensor 410 of the aforementioned IMU 400.
(23) For example, upon detecting an unstable driving situation based on the information measured by the low G sensor 410, the ESC 900 may transmit data to an engine and brake of a vehicle to automatically maintain control power of the vehicle.
(24) The low G sensor 410 included in the IMU 400 is mainly used to control the ESC 900 but, according to the exemplary embodiment of the present invention, a low G sensor for detecting a longitudinal acceleration (ax) may be used for safing.
(25) That is, a general safing algorithm needs a separate safing sensor (acceleration sensor) with a different sensor from the aforementioned main impact sensor 300 but, according to the exemplary embodiment of the present invention, the low G sensor 410 which is pre-included in the IMU 400 may be used to reduce costs.
(26) A general detecting range, i.e., a signal detection range of the low G sensor 410 may be set to −5 to +5 g and, in the case of resolution, the low G sensor 410 may be used to control the ESC 900 and, thus, may have excellent performance compared with a general safing sensor.
(27) However, it is difficult to use a typical low G sensor 410 for safing of collision detection due to the following characteristics.
(28) First, the main impact sensor 300 or the safing sensor needs to have rapid response speed characteristics for airbag deployment.
(29) However, the low G sensor 410 has a phase delay time of about 20 to about 30 ms. The low G sensor 410 has low signal response characteristics (which has delay compared with raw data by about 30 ms) compared with the main impact sensor 300 within about 2 ms and, thus, it may be difficult to use the low G sensor 410 as a safing sensor.
(30) Second, the main impact sensor 300 or the safing sensor needs to perform zero-point adjustment in real time in an initialization or normal operation to prevent collision or determination error due to zero-point drift which is different from an actual situation.
(31) However, the main impact sensor 300 performs zero-point adjustment as a digital method but, the low G sensor 410 may not perform zero-point adjustment. When the low G sensor 410 performs zero-point adjustment in real time, it may be difficult to detect a dynamic situation of a vehicle and, thus, a sensor itself may not perform zero-point adjustment to operate the ESC 900.
(32) Third, a signal detection range of the low G sensor 410 is −5 to +5 g and, in the instant case, there is a problem in that the signal detection range is too narrow to be used in safing for determining whether an airbag is deployed.
(33) Accordingly, it is difficult to use the low G sensor 410 for safing since the low G sensor 410 has slow signal response characteristics, does not perform zero-point adjustment, and has a narrow signal detection range. However, when the low G sensor 410 has an increased signal detection range and rapid signal response characteristics to perform zero-point adjustment, it may be sufficient to use the low G sensor 410 for safing of collision detection.
(34) Accordingly, according to the exemplary embodiment of the present invention, to use the low G sensor 410 for detecting a longitudinal acceleration (ax) in the case of front crash of a vehicle, a filter 500 may be used to overcome delay of response speed of the low G sensor 410.
(35) The filter 500 may convert a first signal detection range of the low G sensor 410 into a second signal detection range and filter an output signal of the low G sensor 410 to generate a first output signal. Here, the first signal detection range may be −5 to +5 g, which is set to control the ESC 900 and the second signal detection range may be −30 to +30 g, which extends compared with the first signal detection range for safing control.
(36) In more detail, the filter 500 may include a converter 510 and a low pass filter (LPF) 520, as shown in
(37) The converter 510 may convert the first signal detection range of −5 to +5 g of the low G sensor 410 for detecting longitudinal acceleration (ax) into the second signal detection range of −30 to +30 g.
(38) The second LPF 520 included in the filter 500 may have a second frequency band and may filter an output signal of the low G sensor 410 to generate a first output signal.
(39) Accordingly, the IMU 400 may include a first low pass filter (LPF) 420 for performing low-filtering on an output signal of the low G sensor 410 in a first frequency band and the second LPF 520 for low-filtering on an output signal of the low G sensor 410 in a second frequency band.
(40) Herein, the signal transmitted through the first LPF 420 may be transmitted to a signal processor 250 of the IMU 400.
(41) The second frequency band of the second LPF 520 may be equal to or less than 400 Hz which extends compared with the first frequency band to be used for safing. For reference, the second frequency band used to control the ESC 900 may be equal to or less than 50 Hz.
(42) The filter 500 may map the output signal, i.e. detecting information (raw data) transmitted from the low G sensor 410, to the second signal detection range of −30 to +30 g through the converter 510 and, then, may pass the output signal with the second frequency band through the second LPF 520 to generate a first output signal with overcome response speed delay.
(43) The adjuster 600 may perform zero-point adjustment on the first output signal transmitted through the filter 500. For example, the adjuster 600 may include an offset cancellation module using software or zero-point adjustment algorithm for adjusting zero-point offset of the first output signal.
(44) Offset of sensor data of the output signal transmitted through the filter 500, such as noise components, may remain. Accordingly, the adjuster 600 may completely perform zero-point adjustment through offset cancellation of removing offset from the sensor data to be used for safing.
(45) However, time delay of a maximum of several tens of seconds may occur (compared with a sensor self-supporting method) up to zero-point stabilization whereby sensor data transmitted through the filter 500 has offset of 0.
(46) Accordingly, even if the sensor data of the low G sensor 410 is transmitted through the filter 500, when zero-point adjustment is not performed within a predetermined time through the adjuster 600 or the low G sensor 410 malfunctions, the corresponding sensor data may not be appropriate to be used for safing.
(47) To the present end portion, the microcomputer 200 may determine whether zero-point offset adjustment is completely performed within a predetermined time.
(48) As the determination result, when zero-point offset adjustment is completely performed within the predetermined time, the microcomputer 200 may determine whether corresponding sensor data satisfies a safing condition.
(49) On the other hand, when zero-point offset adjustment is not completely performed within the predetermined time, the microcomputer 200 may determine whether the safing condition is satisfied based on a detection signal of a front impact sensor (FIS) 700. For example, when a response delay time is within 2 ms, the microcomputer 200 may determine that zero-point adjustment is normally completed and a safing condition is satisfied.
(50) Accordingly, when the first output signal of the low G sensor 410 is satisfied, the first output signal may be used in firing safing of an airbag.
(51) When the safing condition is not satisfied, the low G sensor 410 may not be used as a safing sensor and detecting information of the FIS 700 disposed in a vehicle may be temporarily used for safing, as shown in
(52) Sensors of the FIS 700 may be disposed at two right and left sides of a front portion of an engine compartment to detect direct front crash of a vehicle, differently from the main impact sensor 300 of an airbag. The front impact sensor (FIS) 700 may include a left sensor 710 and a right sensor 720 may be a sensor to which first data is input when crash occurs and which is disposed to early determine whether crash occurs and a crash type.
(53) Accordingly, when zero-point adjustment is not completely performed on the first output signal of the low G sensor 410 or the low G sensor 410 malfunctions, a detection signal of the FIS 700 disposed in the vehicle may be used for safing. Furthermore, when zero-point adjustment is performed on a detecting signal of the low G sensor 410, the low G sensor 410 may be used as a safing sensor. The aforementioned control may be performed by the microcomputer (controller) 200.
(54) Accordingly, the vehicle airbag firing control system according to an exemplary embodiment of the present invention is used, an inertial measurement unit (IMU) integrated into an airbag control unit (ACU) may be used as a safing sensor for airbag firing and, thus, a separate safing sensor may not be required to be included in the ACU.
(55) Even if an inertial measurement unit (IMU) (low G sensor) malfunctions or zero-point adjustment is not completely performed, a front impact sensor may be used as a safing sensor to stably control firing.
(56) Hereinafter, an airbag firing control method using the aforementioned vehicle airbag firing control system will be described.
(57)
(58) Referring to
(59) Then, whether crash occurs may be determined based on a crash signal detected by the main impact sensor 300 (S200). The main impact sensor 300 may transmit the crash signal to the microcomputer 200 and the microcomputer 200 may determine whether the crash signal is a data value required for airbag firing.
(60) Then, the first signal detection range of the low G sensor 410 may be converted into the second signal detection range to use a signal detected by the low G sensor 410 for detecting longitudinal acceleration (ax) of the IMU 400 as a safing sensor (S300).
(61) Operation S300 may be performed by the converter 510 of the filter 500 and may extensively convert signal information (raw data) transmitted from the low G sensor 410 into the second signal detection range of −30 to +30 g from the first signal detection range of −5 to +5 g.
(62) Output of the low G sensor 410, which is converted into the second signal detection range, may be filtered through the LPF 520 of the converter 510 to generate a first output signal (S400).
(63) The adjuster 600 may perform zero-point adjustment on the first output signal transmitted through the filter 500 through offset cancellation (S500). For example, the adjuster 600 may include an offset cancellation module using software or a zero-point adjustment algorithm for adjusting zero-point offset of the first output signal.
(64) Accordingly, the adjuster 600 may be used for safing by completely performing zero-point adjustment through offset cancellation of removing offset from the sensor data
(65) However, time delay of a maximum of several tens of seconds may occur (compared with a sensor self-supporting method) up to zero-point stabilization whereby sensor data transmitted through the filter 500 has offset of 0.
(66) Accordingly, the microcomputer 200 may determine whether zero-point adjustment is completely performed within a predetermined time.
(67) For example, as the determination result, when zero-point offset adjustment is completely performed within the predetermined time, the microcomputer 200 may determine whether corresponding sensor data satisfies a safing condition.
(68) On the other hand, as the determination result, when zero-point offset adjustment is not completely performed within the predetermined time, the microcomputer 200 may determine whether the safing condition is satisfied based on a detection signal of the FIS 700.
(69) Even if the sensor data of the low G sensor 410 is transmitted through the filter 500, when the adjuster 600 detects that zero-point adjustment is not completely performed or the low G sensor 410 malfunctions, output of the low G sensor 410 may not be appropriate for safing.
(70) Accordingly, the microcomputer 200 may determine whether the first output signal of the low G sensor 410 satisfies a safing condition (S410). For example, the safing condition may be satisfied when a time consumed for zero-point adjustment is within a predetermined reference value, a signal response time, i.e., a processing delay time of the first output signal is within 2 ms, and zero-point adjustment is completely performed.
(71) When the safing condition is satisfied, the microcomputer 200 may determine whether an airbag is deployed in consideration of both the output signal of the main impact sensor 300 and the first output signal of the low G sensor 410.
(72) Setting of a safing condition may be different according to a design purpose of one ordinary skill in the art and a safing condition is not particularly limited in an exemplary embodiment of the present invention.
(73) When the first output signal of the low G sensor 410 satisfies the safing condition, the first output signal may be used for safing of airbag firing (S700).
(74) When the safing condition is not satisfied, the low G sensor 410 may not be used as a safing sensor and an auxiliary safing operation in which detecting information of the front impact sensor (FIS) 700 disposed in a vehicle is temporarily used for safing may be performed (S800), as shown in
(75) Accordingly, when zero-point adjustment is not completely performed on the first output signal of the low G sensor 410 or the low G sensor 410 malfunctions, the detection signal of the FIS 700 disposed in the vehicle may be used for safing. Furthermore, while the auxiliary safing operation (S800) is performed, if zero-point adjustment is completely performed on data of the low G sensor 410, the low G sensor 410 may be re-used as a safing sensor. The aforementioned control operations may be performed by the microcomputer (controller) 200.
(76) Accordingly, the vehicle airbag firing control system according to an exemplary embodiment of the present invention is used, an inertial measurement unit (IMU) integrated into an airbag control unit (ACU) may be used as a safing sensor for airbag firing and, thus, a separate safing sensor may not be required to be included in the ACU.
(77) Even if an inertial measurement unit (IMU) (low G sensor) malfunctions or zero-point adjustment is not completely performed, a front impact sensor may be used as a safing sensor to stably control firing.
(78) Accordingly, when an airbag firing control method using the vehicle airbag firing control system according to an exemplary embodiment of the present invention is used, an inertial measurement unit (IMU) integrated into an airbag control unit (ACU) may be used as a safing sensor for airbag firing and, thus, a separate safing sensor may not be required to be included in the ACU.
(79) Even if an inertial measurement unit (IMU) (low G sensor) malfunctions or zero-point adjustment is not completely performed, a front impact sensor may be used as a safing sensor to stably control firing.
(80) When an airbag firing control system of a vehicle and an airbag firing control method using the system according to an exemplary embodiment of the present invention are used, an inertial measurement unit (IMU) integrated into an airbag control unit (ACU) may be used as a safing sensor for airbag firing and, thus, a separate safing sensor may not be required.
(81) Even if an inertial measurement unit (IMU) malfunctions or when zero-point adjustment is not completed, a front impact sensor may be temporarily used for safing.
(82) The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described to explain certain principles of the present invention and their practical application, to enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the present invention be defined by the Claims appended hereto and their equivalents.