Patent Publication Number: US-2007118265-A1

Title: Occupant classifying system and method of vehicle

Description:
This application claims priority on Patent Application No. 10-2005-0112094 filed in Korea on Nov. 23, 2005, No. 10-2005-0127274 filed in Korea on Dec. 21, 2005, and No. 10-2005-0127275 filed in Korea on Dec. 21, 2005, the entire contents of hereby incorporated by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      present invention relates to an occupant classifying system and of a vehicle, and more particularly, to an occupant classifying system and method of a vehicle which, after being initialized with the system&#39;s ignition on, classifies an occupant using information acquired from a weight sensing unit provided in a seat.  
      2. Description of the Related Art  
      In general, occupant protecting devices such as an airbag  2  are mounted in a vehicle to enhance the safety of an occupant getting in the vehicle as shown in  FIG. 1 .  
      Among the occupant protecting devices, an airbag is a device which is instantaneously inflated by high pressure of deployment gases, and its deployment pressure may be excessive or short according to the physical conditions of the occupant to be protected by the occupant protecting device.  
      Accordingly, along with the occupant protecting devices, an occupant classifying system has been developed for evaluating the body conditions of an occupant in the vehicle so that the occupant protecting device can operate optimally according to the body conditions of the occupant in the vehicle.  
      An occupant classifying system according to the prior art classifies an occupant into any one of various classes based on the occupant&#39;s weight.  
      And, the occupant classifying system transmits to the occupant protecting device such as the airbag the occupant classifying information classified into any one of various classes.  
      The occupant classifying system is directly connected to a battery provided in the vehicle and supplied with power recharged in the battery.  
      That is, the occupant classifying system is activated if satisfying a condition to escape from a sleep mode, such as the vehicle&#39;s ignition on, with the battery recharged with power.  
      And, the occupant classifying system is initialized if the vehicle&#39;s ignition is off, and continues to receive power from the battery while operating in the sleep mode in which the occupant classifying system maintains inactivated state.  
      However, the occupant classifying system and method of the vehicle according to the prior art continue to supply power from the battery to the system even after the vehicle&#39;s ignition is off, thus leading to the battery&#39;s continuous power consumption.  
      Therefore, the battery is easily discharged, and if the vehicle&#39;s ignition is off and the battery consumes even more power, When the vehicle&#39;s ignition is restarted, the power supply from the battery is instable. This obstructs the normal driving of the vehicle as well as the occupant classifying system and causes mal-operation of the weight detecting sensor, and, as a result, this may lower the accuracy and reliability of the occupant classifying system.  
      Moreover, since the occupant classifying system and method of the vehicle are initialized after the vehicle&#39;s ignition is off, they fail to reflect the state change or variation of the vehicle from the ignition-off to the ignition restart, and this may reduce the accuracy and reliability of the system.  
     SUMMARY OF THE INVENTION  
      The present invention is designed to overcome the above problems of the prior art, and provides an occupant classifying system and method of a vehicle which may receive power and be initialized when the vehicle&#39;s ignition is started and then classify an occupant into any one of various classes using information acquired from a weight sensing unit.  
      An occupant classifying system of a vehicle according to the present invention to solve the above problems includes a weight sensing unit provided in a seat, a central processing unit classifying the occupant into any one of various classes pre-set using the information acquired by the weight sensing unit, and regulators applying power to the weight sensing unit and central processing unit and initializing the central processing unit whenever the central processing unit is applied smith power.  
      In addition, an occupant classifying method of a vehicle according to the present invention to solve the above problems includes ininitalizing a vehicle if the vehicle&#39;s ignition is on, and classifying an occupant by information acquired through a weight sensing unit provided in a seat if the vehicle is initiialized. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The embodiment of the invention will be described in detail with reference to the following drawings in which like numerals refer to like elements.  
       FIG. 1  is a view of illustrating an airbag, one of occupant protecting devices of a general vehicle.  
       FIG. 2  is a prospective view of illustrating a partial construction of an occupant classifying system of a vehicle according to the present invention.  
       FIG. 3  is a constructional view of an occupant classifying system of a vehicle according to the present invention.  
       FIG. 4  is a flow chart of an occupant classifying method by an occupant classifying system of a vehicle according to the present invention.  
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      Hereafter, preferred embodiments of the present invention will be described in a more detailed manner with reference to the accompanying drawings.  
      FIG,  2  is a prospective view of illustrating a partial construction of an occupant classifying system of a vehicle according to the present invention, and  FIG. 3  is a constructional view of an occupant classifying system of a vehicle according to the present invention.  FIG. 4  is a flow chart of an occupant classifying method by an occupant classifying system of a vehicle according to the present invention.  
      The occupant classifying system according to the present invention is mounted in a passenger seat and includes a weight sensing unit  60  provided in a seat  50 , on which an occupant is seated, and sensing the occupant&#39;s weight, a central processing unit  70  classifying the occupant into any one of various classes pre-set using the information acquired by the weight sensing unit  60 , and regulators  80  applying power to the weight sensing unit  60  and central processing unit  70  and initializing the central processing unit  70  whenever the central processing unit  70  is applied with power.  
      The weight sensing unit  60  comprises weight detecting sensors mounted on at least one point below the seat  50 .  
      As an example, the weight detecting sensor may include a LF weight detecting sensor  61  placed in a left and front side LF of the seat  50 , a RE weight detecting sensor  62  placed in a right and front side RF of the seat  50 , a LR weight detecting sensor  63  placed in a left and rear side LR of the seat  50 , and a RR weight detecting sensor  64  placed in a right and rear side RR of the seat  50 .  
      The central processing unit  70  calculates the occupant&#39;s weight using information for calculating the occupant&#39;s weight pre-set in the central processing unit  70  and information for calculating the occupant&#39;s weight to be inputted to the central processing unit  70 , and classifies the occupant into any one of various classes pre-set through the calculated information for the occupant&#39;s weight.  
      The central processing unit  70  is connected through a K-line communication to an airbag control unit  52  so that the occupant classifying information processed in the central processing unit  70  may be transmitted to an airbag control unit  52  which controls an airbag according to the occupant&#39;s occupancy or vacancy and physical conditions of the occupant seated in the seat  50 .  
      The regulators  80  are provided to apply ignition power  54  to the weight sensing unit  60  and central processing unit  70  so that the occupant classifying system according to the present invention may operate only while the vehicle&#39;s ignition is off to prevent the power consumption of the battery after the vehicle&#39;s ignition is off.  
      In addition, the regulators  80  allow the weight sensing unit  60  and central processing unit  70  to be applied with the ignition power  54  independently with each other so that the ignition power  54  may be stably supplied to the weight sensing unit  60  and central processing unit  70 , respectively.  
      That is, the regulators  80  may be separated into a regulator  82  for a sensor, which converts the ignition power  54  into a voltage suitable for the weight sensing unit  60 , VCC (for example, 5V) when the vehicle&#39;s ignition is started and applies the converted voltage to the weight sensing unit  60 , and a regulator  84  for a CPU, which converts the ignition power  54  into a voltage suitable for the central processing unit  70 , VCC (for example,  5 V) when the vehicle&#39;s ignition is started and applies the converted voltage to the central processing unit  70 .  
      The regulator  84  for the CPU may have a function to output an automatic reset signal to the central processing unit  70  so that the central processing unit  70  may be initialized whenever the ignition power  54  is applied to the central processing unit  70 .  
      The regulator  84  for the CPU may also have a ‘watch-dog’ function to output a compulsory reset signal to the central processing unit  70  so that the central processing unit  70  may be re-initialized in a case where the central processing unit  70  is abnormally operated and turned off under the vehicle&#39;s on.  
      On the other hand, the occupant classifying system according to the present invention further includes diagnosis circuit units  90  for diagnosing the occupant classifying system according to the present invention including whether the central processing unit  70 , regulators  80  as well as the weight sensing unit  60  work normally.  
      The diagnosis circuit units  90  serve to diagnose the occupant classifying system according to the present invention such as whether the weight sensing unit  60  operates well as well as whether the ignition power  54 , VCC, automatic reset signal and compulsory reset signal are outputted normally,  
      Furthermore, the occupant classifying system according to the present invention includes a memory unit  100  for storing and maintaining the evaluating values from the weight sensing unit  60 , primary information, and the diagnosing result from the diagnosis circuit units  90 .  
      The memory unit  100  does store the information not through a separate diagnosing mode but in a real time, and it may be implemented by a FRAM which may maintain the stored information even after the vehicle&#39;s ignition is off.  
      Meanwhile, it is generally obligatory that the occupant to be seated in a driver&#39;s seat and passenger&#39;s seat should fasten the seat belt. Therefore, the occupant classifying system according to the present invention may further include a seat belt fastening and detecting sensor  56  which confirms whether the occupant fastened the seat belt or not, so that the central processing unit  70  may check prudently once more whether the occupant occupied his seat, and then classify the occupant when the central processing unit  70  classifies the occupant according to the occupant&#39;s weight.  
      An occupant classifying method by the occupant classifying system of a vehicle according to the present invention configured as mentioned above will be described as follows.  
      When the vehicle&#39;s ignition is started (step S 2 ), the regulators  80  apply power to the weight sensing unit  60  and central processing unit  70  and at the same time outputs a automatic reset signal to the central processing unit  70  to thereby initialize the central processing unit  70  (step S 4 ).  
      The weight sensing unit  60  and central processing unit  70  receive the power and operate as described above, and the diagnosis circuit units  90  perform a diagnosis while the central processing unit  70  is in the initialized state (step S 6 ).  
      If the diagnosis circuit units  90  determine that the weight sensing unit  60 , central processing unit  70 , and regulators  80  are all operated normally, then an occupant weight calculating mode, which calculates the occupant&#39;s weight, commences.  
      The occupant weight calculating mode is implemented as follows, If the occupant weight calculating mode initiates, then the weight sensing unit  60  detects the weight and outputs the resulting signal to the central processing unit  70 .  
      The signal from the weight sensing unit  60  outputted to the central processing unit  70  is A/D converted and then stored as a LF value, RF value, Lk value, and RR value in the central processing unit  70  (step S 10 ).  
      The LF value is one which is A/D converted from the output signal of the LE weight detecting sensor  61 , the RF value is one which is A/D converted from the output signal the RF weight detecting sensor  62 , the LR value is one which is A/D converted from the output signal of the LR weight detecting sensor  63 , and the RN value is one which is A/D converted from the output signal of the RR weight detecting sensor  64 .  
      If the signal is stored in the central processing unit  70  as the LF value, RF value, LR value, and RR value, then the central processing unit  70  produces a LF data, RF data, LR data, and RR data to be yielded by deducting an offset value of the weight sensing unit  60  pre-set in the central processing unit  70  from each of the LF value, RF value, LR value, and RR value (step S 12 ).  
      The offset value of the weight sensing unit  60  is one which is A/D converted from a signal which under a state that no load is applied on the seat  50 , namely, the occupant&#39;s weight is ‘0’, the weigh sensing unit  60  Outputs to the central processing unit  70 .  
      The offset value of the weight sensing unit  60  may be applied to the four weight detecting sensors  61  to  64  with the same value, or may be applied differently to each of the weight detecting sensors  61  to  64 . Hereinafter, the offset value of the LF weight detecting sensor  61  is referred to as a LF offset, the offset value of the LF weight detecting sensor  62  is referred to as a RF offset, the offset value of the LR weight detecting sensor  63  is referred to as a LR offset, and the offset value of the RR weight detecting sensor  64  is referred to as a RR offset.  
      After the LF data, RF data, LR data, and RR data are yielded, all of them are summed, wherein a total value, which reflects the amendment to the offset value of the weight sensing unit  60 , is produced from the following equation [Total value equation] (step S 14 ). 
 
Total value={ LF  data+ RF  data+ LR  data+ RR  data}+offset amendment value  [Total value equation]
 
      A zero point, which means a value in which the occupant&#39;s weight is 0 among the evaluation values of the weight sensing unit  60 , may increase or decrease due to various causes such as impacts from the outside or aging by elapse of time. Therefore, the offset amendment value is for amending the pre-set offset value of the weight sensing unit  60  so that the zero point of the weight sensing unit  60  may be adjusted.  
      The offset amendment value may be calculated in ‘Auto zero mode’ which will be described later.  
      If the total value is calculated as above, then the occupant&#39;s weight may be yielded from the following equation [occupant&#39;s weight producing equation] (stel) S 16 ). 
 
occupant&#39;s weight=Total value*sensor gain  [occupant&#39;s weight producing equation]
 
      where, the total value is produced from the equation [Total value] as follows, and the sensor gain is a pre-set calculation value to yield in a weight concept the evaluating value of the weight sensing unit  60 , which the signal inputted from the weight sensing unit  60  is A/D converted.  
      If the occupant&#39;s weight is produced, then the weight producing mode ends, and it is determined whether the conditions for the offset amendment value calculating mode for calculating the offset amendment value are satisfied (step S 20 ).  
      One of the conditions for the offset amendment value calculating mode is that no occupant should occupy the seat, and this condition is required since the zero point can be adjusted only when nobody should be seated in the seat  50 .  
      Whether the occupant occupies the seat or not may be handled through the occupant classifying information processed by the central processing unit  70 . At this time, in a case where the vehicle&#39;s ignition is started and then it is for the first time determined whether conditions for the auto zero mode are satisfied, no occupant classifying information exists yet in the central processing unit  70  and thus it is determined that the condition that no occupant should be seated fails to be satisfied.  
      Another one of the conditions for the offset amendment value calculating mode is that the occupant classifying system should operate normally. Whether the occupant classifying system operates normally or not may be handled through the diagnosis circuit units  90 .  
      Unless all of the conditions for the offset amendment value calculating mode are satisfied, then the offset amendment value calculating mode is not performed. That is, only if all the conditions for the offset amendment value calculating mode should be satisfied, the offset amendment value calculating mode starts.  
      If the offset amendment value calculating mode commences, then at first a current offset value of the weight sensing unit  60  acquired through the occupant&#39;s weight calculating mode and the initial offset value of the weight sensing unit  60  are compared with each other (step S 22 ).  
      If the current offset value and initial offset value of the weight sensing unit  60  are equal, then the offset amendment value calculating mode ends without varying the pre-set offset amendment value.  
      Otherwise, in a case where the current offset value and initial offset value of the weight sensing unit  60  are different, if the current offset value of the weight sensing unit  60  is smaller than the initial offset value of the weight sensing unit  60 , it is classified into an UP condition, and if the current offset value of the weight sensing unit  60  is greater than the initial offset value of the weight sensing unit  60 , it is classified into a DOWN condition (step S 24 ). Herein, since the variation of the zero point of the weight sensing unit  60  may be a temporary phenomenon due to loads from books or bags put on the seat  50 , at first, the number of times of the conditions for the offset amendment is accumulated (steps S 25  and S 25 ′).  
      It is desirable that the number of times of the conditions for the offset amendment is accumulated only once, since the loads from books or bags put on the seat  50  can last for long time.  
      If the number of times of the conditions for the offset amendment is accumulated, then the accumulated number of times of the conditions for the offset amendment is compared with the pre-set value. At this time, the pre-set value to be compared with the accumulated number of times of the conditions for the offset amendment may be different according to whether the classified condition is the UP condition or DOWN condition (steps S 26  and S 26 ′).  
      As a result of the comparison of the accumulated number of times of the conditions for the offset amendment and the pre-set value, if the accumulated number of times of the conditions for the offset amendment is smaller than the pre-set value, then the offset amendment value calculating mode ends without varying the pre-calculated offset amendment value.  
      Otherwise, if the accumulated number of times of the conditions for the offset amendment reaches the pre-set value, then the pre-calculated offset amendment value is recalculated (steps S 28  and S 28 ′).  
      The offset amendment value can be calculated to allow the offset amendment value to be increased or decreased by a predetermined increment or by the difference of the current offset value and initial offset value of the weight sensing unit  60 . At this time, in case of the UP condition, where the current offset value of the weight sensing unit  60  is smaller than the initial value of the weight sensing unit  60 , the offset amendment value is increased, and in case of the DOWN condition, where the current offset value of the weight sensing unit  60  is greater than the initial value of the weight sensing unit  60 , the offset amendment value is decreased.  
      If the offset amendment value is calculated as described above, then the offset amendment value calculating mode ends.  
      In a case where the above invention offset amendment value calculating mode ends or the conditions for the offset amendment value calculating mode fail to be satisfied, an occupant classifying mode starts, which classifies an occupant into any one of various classes using the occupant&#39;s weight calculated in the occupant&#39;s weight calculating mode.  
      If the occupant classifying mode starts, then it determines which range of the pre-set various classes the calculated occupant&#39;s weight corresponds to (step S 30 ), and classifies the occupant into any one of the pre-set various classes (steps S 32 , S 34 , and S 36 ).  
      Here, the pre-set classes include a class  0  where no occupant is seated in the seat, a class  1  where the occupant is classified into a child or small lady, and a class  2  where the occupant is classified into an adult.  
      On the other hand, in a case where the occupant is classified into the class  0 , the occupant is not immediately determined as the class  0  and it is determined whether the occupant fastens the seat belt (step S 38 ). If the occupant does not fasten the seat belt, then the occupant is determined as the class  0  (step S 32 ), and if the occupant fastens the seat belt, then the occupant is considered as a chilled or small lady and reclassified into the class  1 , a level right above the class  0 , and then determined as the class  1  (step S 34 ).  
      If the occupant is determined as any one of the classes, then the occupant classifying mode ends.  
      If the occupant classifying mode ends, then occupant classifying information acquired through the occupant classifying mode is transmitted through K-line communication to the airbag control unit  52  (step S 40 ).  
      Hereafter, if the vehicle is on, then the occupant classifying system according to the present invention would repeat all the steps from the beginning, and if the vehicle&#39;s ignition is off, then the occupant classifying system would stop the operation (step S 50 ).  
      On the other hand, as a result of the diagnosis of the diagnosis circuit units  90  (step S 4 ), if any one of the weight sensing unit  60 , central processing unit  70 , and regulators  80  is diagnosed as being operated abnormally, then the result of the diagnosis would be stored in the memory unit  100  (step S 60 ). The result of the diagnosis may be transmitted through the K-Line communication to the airbag control unit  52  (step S 40 ).  
      And, if the vehicle is still under operation, then the vehicle classifying system would be forced to be initialized again (step S 4 ).  
      Although the occupant classifying system and method according to the present invention is described with reference to the exemplary drawings, the invention is not limited to the embodiments and drawings set forth herein, rather it is limited only to the accompanying claims.  
      The occupant classifying system and method according to the present invention configured and operated as mentioned above are initialized if power is applied and then classify the occupant into any one of various classes using the information acquired from the weight sensing unit, and this allows for optimizing the vehicle&#39;s current state, thus making it possible to improve the accuracy and reliability.  
      Moreover, the occupant classifying system and method according to the present invention configured and operated as mentioned above receive the ignition power so that power is supplied to the vehicle if the vehicle&#39;s ignition is started up, and thus may be stably supplied with power, thus making it possible to maximize the accuracy and reliability and to prevent the discharge of the battery when the vehicle&#39;s ignition is off.  
      In addition, the occupant classifying system and method according to the present invention configured and operated as mentioned above may make an amendment to the offset value of the weight sensing unit by implementing the offset amendment value calculating mode and this allows for adjusting a zero point of the weight sensing unit all the time, thus making it possible to maximize the accuracy and reliability. This allows for improving the performance and stability of airbags to be controlled by the occupant classifying information.  
      In addition, the occupant classifying system and method according to the present invention configured and operated as mentioned above are provided to recalculate the offset amendment value of the weight sensing unit if the offset amendment value of the weight sensing unit is varied over the predetermined number of times, thus making it possible to maximize the accuracy and reliability.  
      In addition, the occupant classifying system and method according to the present invention configured and operated as mentioned above reconsider the occupant&#39;s classification according to whether the occupant fastens or not in a case where the occupant is classified into the class  0 , thus making it possible to the accuracy and reliability.