Abstract:
A method of pre-crash prediction of the severity of an imminent crash of road vehicles is disclosed using a pre-crash sensor, a computer system coupled with pre-crash vehicle condition signal sources and a vehicle communication system onboard each of two vehicles involved in a crash. The method includes the steps of determining that a collision of the vehicles is imminent, exchanging vehicle crash-related information between the vehicles when an imminent collision is determined, computing crash-defining information onboard each vehicle and predicting onboard each vehicle the severity of the imminent collision whereby occupant protection devices of the vehicles may be deployed in accordance with the predicted severity.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a continuation application of U.S. Pat. Ser. No. 09/782,461, filed on Jan. 22, 2001, which is herein incorporated by reference in its entirety. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates to pre-crash warning systems for road vehicles. More particularly, it relates to a system for robustly assessing the expected severity of an impending crash of two vehicles.  
         BACKGROUND OF THE INVENTION  
         [0003]    In currently-available pre-crash warning systems for road vehicles, the safety benefits are limited because such systems do not provide sufficient information about the object in the path of the vehicle to reliably predict the severity of an imminent crash. For example, currently-available systems cannot distinguish between two vehicles which are about the same size but which have significantly different mass and hence have critically different crash characteristics. Consequently, the safety benefits of such pre-crash warning systems are limited to (1) pre-arming of non-resettable devices, such as airbags, so that they can be deployed more rapidly in cases where the subsequent collision is sufficiently severe to warrant deployment, and (2) triggering non-aggressive resettable safety devices that do not interfere with the vehicle driving function, such as extendible/retractable bumpers and extendible/retractable knee bolster systems. There is a need for pre-crash warning systems which not only give warning of an imminent crash but also predict the severity of the crash.  
           [0004]    In the prior art, the Sekine U.S. Pat. No. 5,546,311 granted Aug. 13, 1996 describes an intercommunication system for vehicles which supplies speed and direction information for the purpose of collision avoidance.  
           [0005]    Other prior art patents relating to collision avoidance systems are Blowney et al U.S. Pat. No. 3,097,354 granted Jul. 9, 1963; Gilon et al U.S. Pat. No. 5,684,474 granted Nov. 4, 1997 and Giovanni U.S. Pat. No. 5,841,367 granted Nov. 24, 1998.  
           [0006]    The known prior art does not disclose a system for exchanging critical vehicle crash-defining information between two vehicles in an imminent crash situation, predicting the severity of the crash and controlling occupant protection devices in accordance with the prediction.  
         SUMMARY OF THE INVENTION  
         [0007]    In accordance with this invention, a system is provided which predicts the severity of an imminent collision of two vehicles based upon robust crash-defining information about both vehicles.  
           [0008]    Further, in accordance with the invention, the robust crash-defining information about both vehicles is developed after the collision becomes inevitable and imminent. Further, the prediction of crash severity is developed in time so that occupant safety devices can be deployed in accordance with the predicted crash severity.  
           [0009]    Further, in accordance with this invention, road vehicles are provided with pre-crash warning systems with automatic means for exchanging critical vehicle crash information between two vehicles when a collision between the two vehicles is determined to be inevitable and imminent. The critical information is used to deploy non-reversible and reversible safety systems when a collision is imminent.  
           [0010]    Further, in accordance with this invention, a method of predicting the severity of an imminent collision of two vehicles is provided whereby occupant protection devices of the vehicles may be deployed in accordance with the predicted severity. The method comprises the steps of determining that a collision of the vehicles is imminent, exchanging vehicle crash-related information between the vehicles, computing crash-defining information onboard each vehicle based upon the crash-related information and predicting onboard each vehicle the severity of the imminent collision based upon the computed crash-defining information.  
           [0011]    Further, in accordance with this invention, apparatus for use onboard a road vehicle is provided for predicting the severity of an imminent collision and for controlling deployment of occupant protection devices in accordance with the prediction. The apparatus comprises means for determining whether the vehicle is closing on another vehicle and for producing a warning signal when a collision of the two vehicles is imminent, means responsive to the warning signal for transmitting crash-related information to the other vehicle, means for receiving crash-related information from the other vehicle, and computer means for processing said crash-related information from both vehicles and for predicting the severity of the collision, whereby the occupant protection devices may be deployed in accordance with the severity.  
           [0012]    Further, in accordance with this invention, the critical information is exchanged between the two vehicles by means such as electromagnetic, optical or ultrasonic systems. Alternatively, the critical information is exchanged by use of satellite-based systems or by use of radio transceiver or transponder systems.  
           [0013]    A complete understanding of this invention may be obtained from the detailed description that follows taken with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a functional block diagram which shows a crash severity prediction system installed in a first road vehicle, and  
         [0015]    [0015]FIG. 2 is a functional block diagram of a crash severity prediction system which is identical to that of FIG. 1 but is installed in a second road vehicle.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]    Referring now to the drawings, there is shown an illustrative embodiment of the invention which is adapted for use in controlling the deployment of passenger protection devices in land vehicles. It will be appreciated, as the description proceeds, that the invention is useful in a wide variety of applications and may be implemented in many different ways.  
         [0017]    [0017]FIG. 1 is a block diagram representation of a crash severity prediction system  10 A which is installed in a vehicle A, and FIG. 2 is block diagram of an identical crash severity prediction system  10 B installed in vehicle B. The crash severity prediction system  10 A will be described with reference to FIG. 1; the description is applicable also to the crash severity prediction system  10 B. The corresponding components of systems  10 A and  10 B are identified by the same reference characters except that a prime symbol is added to the reference characters in system  10 B.  
         [0018]    General Description of the Crash Severity Prediction System  
         [0019]    An overview of the crash severity prediction system  10 A will be given before the system is described in detail. The system  10 A comprises, in general, a computer system  2 , a pre-crash sensor  12  and a communication system  6  which communicates with vehicle B. The pre-crash sensor  12  supplies the computer system  2  with closing speed, range and, optionally, the angle of approach between vehicles A and B. The computer system  2  also receives crash-related vehicle information including vehicle crash characteristics, vehicle speed, heading and the operating status of the brakes, steering wheel and the like, which are referred to collectively as pre-crash vehicle condition signals  4 . The computer system  2  predicts the severity of an imminent crash based upon the signals received from the pre-crash sensor  12  and the signals  4 . It also develops control signals for occupant protection devices  16 .  
         [0020]    The computer system  2  comprises a vehicle dynamics computer  20  and a pre-crash processing computer  14 . The vehicle dynamics computer  20  receives the pre-crash vehicle condition signals  4  and operates on the signals to develop vehicle A condition-defining signals  17 . Also, the vehicle dynamics computer  20  receives vehicle B condition-defining signals  17 ′ via the vehicle A communication system  6 . The vehicle dynamics computer  20  processes the vehicle A and vehicle B condition-defining signals  17  and  17 ′ to develop vehicle A crash-defining data signals  21  which are applied to the pre-crash processing computer  14 .  
         [0021]    The pre-crash processing computer  14  receives a pre-crash warning signal  13  from the pre-crash sensor  12  and generates an alert or handshake signal  27  to initiate communication with vehicle B. The pre-crash processing computer  14  processes the crash-defining data signals  21  to assess the severity of the impending collision and to generate control signals  15  for controlling deployment of the occupant protection devices  16 .  
         [0022]    The communication system  6  of vehicle A comprises transmitter  28  for transmitting signals to vehicle B and comprises receiver  24  for receiving signals from vehicle B. Preferably, the transmitter and receiver operate in the manner of either a transceiver or a transponder.  
         [0023]    Description of Individual Stages  
         [0024]    The individual stages of crash-sensing prediction system  10 A will now be described further in regard to function and implementation. Since the required functions of each individual stage can be realized by known designs using readily-available components, details of circuitry and structure will not be given. However, it will be helpful to provide further description, especially in respect to the function of each individual stage and the functional relationship among the different stages.  
         [0025]    Pre-Crash Sensor  
         [0026]    The pre-crash sensor  12  in the illustrative embodiment of FIG. 1 develops closing speed and range signals and, optionally, the angle of approach between vehicles A and B.  
         [0027]    These signals are used to produce the pre-crash warning signal  13  when the sensed conditions indicate that a crash of the vehicles A and B is imminent. The pre-crash warning signal is applied to the pre-crash processing computer  14 .  
         [0028]    The pre-crash sensor  12  is suitably a collision-sensing system of the type using radar or lidar or of the type using ultrasonics. The collision-sensing system itself must be capable of measurements in the near range of 0 to 20 meters for use in assessing crash severity. Radar systems in the 20 GHz range or higher, lidar systems, and also ultrasonic systems are known having this capability.  
         [0029]    Pre-Crash Processing Computer  
         [0030]    The pre-crash computer  14  is a digital computer which computes an assessment of the severity of an imminent collision based upon crash-defining data signals  21  from the vehicle dynamics computer  20  which represent the relative speed, angle and location of impact, energy levels of the vehicles and, if available, crush forces associated with those locations of impact. Based upon the data signals  21 , the pre-crash processing computer  14  computes a prediction of the severity of an imminent crash and produces control signals  15  for controlling actuation of occupant protection devices  16  which may include but are not limited to airbags, seat belts, extendible/retractable bumpers and knee bolsters.  
         [0031]    The pre-crash processing computer  14  is operative in response to the pre-crash warning signal  13  from the pre-crash sensor  12  to generate a handshake signal  27  which is applied to the transmitter  28  for transmission to vehicle B. This initiates transmission from vehicle B of a return handshake signal  27 ′ (generated by the pre-crash processing computer  14 ′) to vehicle A which is supplied by the receiver  24  to the pre-crash processing computer  14 . Upon receipt of the return handshake signal, the vehicle dynamics computer  20  is activated to exchange vehicle condition-defining signals  17  and  17 ′ with vehicle dynamics computer  20 ′.  
         [0032]    Vehicle Dynamics Computer  
         [0033]    The vehicle dynamics computer  20  is a digital computer which receives the pre-crash vehicle condition signals  4  and develops the crash-defining data signals  21  which are supplied to the pre-crash processing computer  14 . The pre-crash vehicle condition signals  4  are supplied from a vehicle identification read only memory (ROM)  26 , onboard sensors  24  and, optionally, a global positioning system (GPS)  17 . The information obtained from these sources taken with that from the pre-crash sensor is sufficient for the vehicle dynamics computer  20  to develop the vehicle A condition-defining signals  17 .  
         [0034]    The vehicle A condition-defining signals  17  are applied to transmitter  28  which transmits the signals to the receiver  24 ′ of vehicle B and thence the signals  17  are applied to the vehicle dynamics computer  20 ′.  
         [0035]    Vehicle dynamics computer  20  also receives the vehicle B condition-defining signals  17 ′ which are transmitted from vehicle B and applied to the receiver  24  and thence to the vehicle dynamics computer  20 . The vehicle B condition-defining signals  17 ′ contain crash-related information of the same type as that which is contained in the vehicle A condition-defining signals  17 .  
         [0036]    The vehicle dynamics computer  20  processes the vehicle condition-defining signals  17  and  17 ′ of vehicles A and B and develops the crash-defining data signals  21  representing the relative speed, energy levels of the two vehicles, location of impact and, subject to data availability, crush forces that will be generated at such locations.  
         [0037]    Pre-Crash Vehicle Condition Signals  
         [0038]    The pre-crash vehicle condition signals  4  in the illustrative embodiment are supplied from the vehicle identification read only memory (ROM)  26 , onboard sensors  22  and optionally a global positioning system  18 .  
         [0039]    The vehicle identification ROM  26  defines characteristics of vehicle A related to the crashworthiness of the vehicle. Such characteristics may include mass, dimensions and crash pulse of the vehicle. Vehicle identification signals  25  are read from the ROM  26  into the vehicle dynamics computer  20 .  
         [0040]    The global positioning system  18  is the On-Star™ system (made by General Motors Corporation) or equivalent and supplies vehicle condition defining signals  19  which enable the vehicle dynamics computer to develop position, heading and speed of the vehicle.  
         [0041]    The on-board sensors  22  in the illustrative embodiment supply the vehicle dynamics computer  20  with signals  23  representing speed, acceleration, yaw rate, steering wheel position, braking status, throttle position, and transmission status.  
         [0042]    The Communication System  
         [0043]    In the illustrative embodiment of the invention, the communication system  6  comprises receiver  24  and transmitter  28 . The receiver  24  and the transmitter  28  are preferably coupled in a manner so as to operate as a transceiver with the common antenna  30 . The transmitter  28  receives signals  27  from the pre-crash processing computer  14  and also receives signals  17  from the vehicle dynamics computer  20  and transmits output signals  29  which are received by the receiver  24 ′ of the crash severity prediction system  10 B of vehicle B. The input signals to the transmitter  28  include the handshake signal  27  and the vehicle A condition-defining signal  17  from the vehicle dynamics computer  20 . The receiver  24  is adapted to receive input signals including a handshake signal and the condition-defining signal  17 ′ transmitted by the crash severity prediction system  10 B of vehicle B. The process of exchanging information must be accomplished within a matter of milliseconds, such as a period of 10 to 20 milliseconds.  
         [0044]    In an alternative communication system (not shown), information is exchanged between vehicles using the pre-crash sensor  12  and modulating its emitted carrier wave to represent the information to be exchanged.  
         [0045]    As another alternative, exchanging information between the vehicles can be done, once an imminent collision has been detected, by using satellite-based systems such as the On-Star™ system.  
         [0046]    Another alternative is a transponder system using a frequency band exclusively reserved for vehicle crash safety systems. In a transponder system, information is exchanged by a signal transmission from one vehicle to the other which triggers the automatic return of a signal transmission by a transponder on the other vehicle.  
         [0047]    Occupant Protection Devices  
         [0048]    The occupant protection devices  16  include but are not limited to non-resettable devices such as air bags and resettable safety devices such as extendable and retractable bumpers and extendable and retractable knee bolster systems. The timing and extent of deployment of each of these devices is controlled by control signals  15 .  
         [0049]    Operation of the Crash Severity Prediction System  
         [0050]    It will be understood that the benefits of this invention cannot be realized unless both vehicles involved in an impending collision are equipped with the crash severity prediction system. Accordingly, the operation will now be described in the situation in which the two vehicles A and B are involved.  
         [0051]    In the case where the two vehicles A and B are closing on each other, it will be assumed that the pre-crash sensor  12  of vehicle A is the first to transmit a pre-crash warning signal  13  when a crash of the vehicles is imminent. The pre-crash processing computer  14  supplies a handshake signal  27  to the transmitter  28 , and the signal is detected by the receiver  24 ′ of vehicle B. This causes the transmitter  28 ′ of vehicle B to send a return handshake signal  27 ′ which is detected by receiver  24  of vehicle A and applied to the pre-crash processing computer  14 . This establishes communication between the vehicles with vehicle A having preempted the initiation of information exchange between them. The vehicle dynamics computer  20  of vehicle A responds to the return handshake signal by applying the vehicle A condition-defining signals  17  to the transmitter  28  which sends it to vehicle B which, in turn, applies the signal to the vehicle dynamics computer  20 ′ of vehicle B. Immediately after vehicle B sends the return handshake signal, it also sends the vehicle B condition-defining signals  17 ′ to vehicle A which applies those signals to the vehicle dynamics computer  20 .  
         [0052]    The vehicle dynamics computer  20  of vehicle A processes the vehicle A and vehicle B condition-defining signals  17  and  17 ′ and develops the crash-defining data signals  21  which are applied to the pre-crash processing computer  14  of vehicle A. The pre-crash processing computer  14  processes the crash-defining data signals  21  to predict the severity of the imminent crash and to develop control signals  15  which determine the timing and extent of deployment of the associated occupant protection devices  16 . Similarly, in vehicle B, the vehicle dynamics computer  20 ′ processes the vehicle A condition-defining signals  17  and the vehicle B condition-defining signals  17 ′ and develops the crash-defining data signals  21 ′ which are applied to the pre-crash computer  14 ′. The pre-crash processing computer  14 ′ predicts the severity of the imminent crash and develops the control signals  15 ′ which determine the timing and extent of deployment of the associated occupant protection devices  16 ′.  
         [0053]    Conclusion  
         [0054]    A method of and apparatus for predicting the severity of an imminent collision of two vehicles is described above. The prediction of severity is early enough so that the timing and extent of deployment of occupant protection devices can be controlled in accordance with the predicted crash severity.  
         [0055]    Although the description of this invention has been given in reference to a particular embodiment, it is not to be construed in a limiting sense. Many variations and modifications of the invention will now occur to those skilled in the art. For a definition of the invention, reference is made to the appended claims.