Abstract:
Provided is an airbag control unit with inertial measurement unit (IMU) integration, which includes an airbag collision sensor configured to detect airbag collision information; a digital sensor configured to detect a yaw rate and an acceleration, and to convert a detected data to a digital signal; and a micom configured to identify whether an output from the digital sensor and an output from the airbag collision sensor are within a measurement range of a corresponding sensor.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    Priority to Korean patent application number 10-2010-122043, filed on Dec. 2, 2010, which is hereby incorporated by reference in its entirety, is claimed. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an airbag control unit with inertial measurement unit (IMU) integration, and more particularly, to a technology for integrating a yaw rate sensor and vertical/horizontal gravity sensors (G sensor), which are formed as a separate unit and connected to an electronic stability control (ESC) unit, with an airbag control unit (ACU), thereby improving a layout of an in-vehicle device. 
         [0004]    2. Description of the Related Art 
         [0005]    A yaw rate sensor and a G sensor are sensors that are necessary to perform steering control of a vehicle. Specifically, the yaw rate sensor is a sensor that measures a vehicle&#39;s yaw rate (angular velocity) around a vertical axis of the vehicle and is used for 4 wheel steering control of the vehicle. The G sensor (gravity sensor), which is also called an accelerometer sensor, processes an output signal to measure moving inertia of the vehicle. 
         [0006]    As shown in  FIG. 1 , the yaw rate sensor and the G sensor include an electronic stability control (ESC) unit  10  and a sensor unit, which is formed as a separate unit from the ESC unit  10 . 
         [0007]    As illustrated in  FIG. 1 , the sensor unit (inertial measurement unit (IMU))  20  includes a vertical G sensor unit  40  for detecting acceleration along an X axis. The sensor unit also includes a horizontal G/yaw rate sensor unit  50  for detecting acceleration along a Y axis and a yaw rate. 
         [0008]    The vertical G sensor  40  includes an X-axis acceleration sensor  41  and a power supply unit  40 . The horizontal G/yaw rate sensor unit  50  includes a yaw rate sensor  51 , a Y axis acceleration sensor  52 , a micom  55  and a power supply unit  54 . In the conventional design shown in  FIG. 1 , the airbag control unit (ACU)  30  includes an airbag collision sensor  31 , which includes an acceleration sensor and a roll rate sensor, a micom  32  and a power supply unit  33 . 
         [0009]    As shown in  FIG. 2 , a value sensed by the sensor unit  20  is transmitted to the ESC unit  10  where filters  11  and  12  of the ESC  10  perform filtering on the sensed value. Then an A/D converter  13  converts the sensed value to a digital signal and a determination unit  16  determines whether the converted digital signal is an appropriate signal by comparing the digital signal with a self-test signal. Next, a computation unit  18  conducts computation for performing calibration and a calibration unit  17  performs offset calibration on the digital signal. 
         [0010]    Thus, in a related art, the yaw rate sensor and the vertical/horizontal G sensors are formed as a separate unit from the ESC unit  10 , thereby occupying a larger portion of an in-vehicle area. 
         [0011]    In addition, because the ESC  10  performs the filtering, calibration, and determination on an output value of the yaw rate sensor and the vertical/horizontal G sensors, a heavy load is applied to the ESC unit  10 . 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention provides an airbag control unit that is integrated with a digital sensor, in which a separate yaw rate sensor and separate vertical/horizontal G sensors are integrated, so that a layout of an in-vehicle device can be improved. 
         [0013]    In addition, an output value of the yaw rate sensor and the vertical/horizontal G sensors are processed by a micom of the airbag control unit so that a load applied to the ESC unit can be reduced. 
         [0014]    In accordance with an aspect of the present invention, an airbag control unit with inertial measurement unit (IMU) integration is provided. The airbag control unit in this embodiment of the present invention may include an airbag collision sensor configured to detect an airbag collision information; a digital sensor configured to detect a yaw rate and an acceleration. The digital sensor in the airbag control unit may also be configured to convert a detected data to a digital signal. Additionally, a micom may be configured to identify whether an output from the digital sensor and an output from the airbag collision sensor are within a measurable range of a corresponding sensor. 
         [0015]    It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The objects, features and advantages of the present invention will be more apparent from the following detailed description in conjunction with the accompanying drawings, in which: 
           [0017]      FIG. 1  is a diagrammatic view illustrating a conventional configuration in which a yaw rate sensor and a conventional vertical/horizontal G sensor are installed; 
           [0018]      FIG. 2  is a diagrammatic view for explaining the flow of an output signal of the conventional yaw rate sensor and the conventional vertical/horizontal G sensor in  FIG. 1 ; 
           [0019]      FIG. 3  is a diagrammatic view illustrating a configuration of an airbag control unit with IMU integration according to an exemplary embodiment of the present invention; and 
           [0020]      FIG. 4  is a diagrammatic view illustrating an exemplary detailed configuration of a digital sensor and a micom in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0021]    Exemplary embodiments of the present invention are described with reference to the accompanying drawings in detail. The same reference numbers are used throughout the drawings to refer to the same or like parts. Detailed descriptions of well-known functions and structures incorporated herein may be omitted to avoid obscuring the subject matter of the present invention. 
         [0022]    It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles. 
         [0023]    Hereinafter, an airbag control unit with IMU integration according to the present invention will be described with reference to  FIGS. 3 and 4 . 
         [0024]      FIG. 3  is a view illustrating a configuration of an airbag control unit (ACU) with IMU integration according to an exemplary embodiment of the present invention. The integrated ACU  200  with IMU integration according to an exemplary embodiment of the present invention includes an airbag collision sensor  210 , a micom  220 , a power supply unit  230  and a digital sensor  240 . 
         [0025]    Specifically, the airbag collision sensor  210  is used to sense acceleration and roll rate. The micom  220  filters and measures an output value of the airbag collision sensor  210  and an output value of the digital sensor  240 , and performs a data conversion thereon to enable controller area network (CAN) communication. To this end, the micom  220  includes an SPI interface  221 , a filter  222 , a determination unit  223  and a data conversion unit  224 , as shown in  FIG. 4 . 
         [0026]    The SPI interface  221  receives the output value of the digital sensor  240  that is output in an SPI mode. The filter  222  filters data received at the SPI interface  221 , and the determination unit  223  detects an error condition of the filtered data by identifying whether the filtered data is within a measurable range of the sensor. The data conversion unit  224  converts data outputted from the determination unit  223  to a data in compliance with CAN communication protocol and transmits the converted data to an electronic stability control (ESC) unit  100 . 
         [0027]    The power supply unit  230  provides power to the airbag collision sensor  210 , the micom  220  and the digital sensor  240 . 
         [0028]    The digital sensor  240  measures dynamic force such as a vehicle&#39;s yaw rate (angular velocity) around a vertical axis of the vehicle, acceleration along an X-axis and a Y-axis of the vehicle, and vibration and impact of the vehicle The digital sensor then converts the detected value to a digital signal, and performs filtering and calibration on the converted digital signal. 
         [0029]    To this end, the digital sensor  240  may have the exemplary detailed configuration as shown in  FIG. 4 . 
         [0030]    In  FIG. 4 , the digital sensor  240  includes a digital-to-analog converter (DAC) for converting a digital signal to an analog signal, a capacitance-to-voltage conversion (CV), an automatic gain control (AGC) for controlling a gain of a received signal, an analog-to-digital (AD) converter for converting an analog sensing value into a digital signal, a phase locked loop (PLL), a filter FILTER for filtering a signal, an one-time programmable (OTP)  300 , a safety controller (SCON)  290  for performing an offset calibration according to vehicle set-up conditions, a temperature sensor (TEMP SENS)  270  for correcting an output according to temperature characteristics, and a serial peripheral interface (SPI)  280  for outputting a corrected value in the SPI mode. 
         [0031]    The digital sensor  240  converts the yaw rate value and the acceleration value, which are physically measured, to a digital signal, and performs filtering and calibration on the digital signal to send to the micom  220 . Next, the micom  220  filters the calibrated data, identifies whether the data is within a measurable range of the sensor, and converts the data into a data in compliance with the CAN protocol. The converted data is outputted to a CAN communication bus so that the data is transmitted to the ESC unit  100 . 
         [0032]    As described above, according to the present invention, a micom  220  and a power supply unit  230  of an integrated ACU  200  can be used in replacement of the power supply unit  42  of the vertical G sensor unit  40  and the micom  55  and the power supply unit  54  of the horizontal G/yaw rate sensor unit  50 , thereby providing an improved layout and reducing the number of components, which results in lower manufacturing costs. 
         [0033]    In addition, according to the present invention, the output of the yaw rate sensor and the output of the vertical/horizontal G sensor are processed through the micom of the air bag control unit, thereby minimizing a load of ESC unit. 
         [0034]    Although exemplary embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and modifications of the basic inventive concepts herein taught which may appear to those skilled in the present art will still fall within the spirit and scope of the present invention, as defined in the appended claims.