Abstract:
A system for sensing a potential collision of a first vehicle ( 11 ) with a second vehicle ( 72 ) that transmits a second position signal. The first vehicle has a pre-crash sensing system ( 10 ) includes a memory ( 14 ) that stores vehicle data and generates a vehicle data signal. A first global positioning system ( 18 ) generates a first position signal corresponding to a position of the first vehicle. A first sensor ( 20 ) generating sensor data signals from the first vehicle. A receiver ( 22 ) receives a second position signal and a road condition signal from the second vehicle. A countermeasure system ( 40 ) is also coupled within the first vehicle. A controller ( 12 ) is coupled to the memory ( 14 ), the global positioning receiver ( 18 ) the first sensor ( 20 ) and the counter measure system ( 40 ). The controller ( 12 ) determines a distance to the second vehicle in as a function of the second position signal. The controller determines a first vehicle trajectory from the sensor data signals and the position signal. The controller ( 12 ) determines a threat level as a function of the distance, the first vehicle trajectory and the road condition signal and activates the counter-measure system in response to the threat level.

Description:
RELATED APPLICATIONS 
     The present invention is related to U.S. applications Ser. No. 09/683,603, filed Jan. 24, 2002, entitled “Method and Apparatus for Activating a Crash Countermeasure in Response to the Braking Capability of a Vehicle” and Ser. No. 09/683,589, filed Jan. 23, 2002, entitled “Method and Apparatus for Activating a Crash Countermeasure” filed simultaneously herewith and hereby incorporated by reference. 
    
    
     BACKGROUND OF INVENTION 
     The present invention relates to pre-crash sensing systems for automotive vehicles, and more particularly, to side impact pre-crash sensing systems having counter-measures operated in response to pre-crash detection. 
     Auto manufacturers are investigating radar, lidar, and vision-based pre-crash sensing systems to improve occupant safety. Current vehicles typically employ accelerometers that measure forces acting on the vehicle body. In response to accelerometers, airbags or other safety devices are employed. Also, Global Position Systems (GPS) systems are used in vehicles as part of navigation systems. 
     In certain crash situations, it would be desirable to provide information to the vehicle operator before forces actually act upon the vehicle. As mentioned above, known systems employ combinations of radar, lidar and vision systems to detect the presence of an object in front of the vehicle a predetermined time before an actual crash occurs. 
     Other systems broadcast their positions to other vehicles where the positions are displayed to the vehicle operator. The drawback to this system is that the driver is merely warned of the presence of a nearby vehicle without intervention. In a crowded traffic situation, it may be difficult for a vehicle operator to react to a crowded display. 
     It would be desirable to provide a system that takes into consideration the position of other vehicles and, should the situation warrant, provide crash mitigation. 
     SUMMARY OF INVENTION 
     The present invention provides an improved pre-crash sensing system that deploys a counter-measure in response to the position the object detected. 
     In one aspect of the invention, a system for sensing a potential collision of a first vehicle with a second vehicle that transmits a second position signal. The first vehicle has a pre-crash sensing system includes a memory that stores vehicle data and generates a vehicle data signal. A first global positioning system generates a first position signal corresponding to a position of the first vehicle. A first sensor generates sensor data from the first vehicle. A receiver receives a second position signal and a road condition signal from the second vehicle. A countermeasure system is also coupled within the first vehicle. A controller is coupled to the memory, the global positioning receiver the first sensor and the counter measure system. The controller determines a distance to the second vehicle in as a function of the second position signal, determines a first vehicle trajectory from the vehicle data, the first sensor signal and the position signal. The controller determines a threat level as a function of the distance, the first vehicle trajectory and the road condition signal and activates the counter-measure system in response to the threat level. 
     In a further aspect of the invention, a method for operating a pre-crash sensing system for a first vehicle proximate a second vehicle a counter-measure system comprising: generating a first position signal corresponding to a position of the first vehicle; generating sensor signals from the first vehicle; receiving a second position signal from the second vehicle; and receiving a first road condition signal; determining a distance to the second vehicle in as a function of the second position signal; determining a first vehicle trajectory from said vehicle data, said sensor signals, said first position signal and said second position signal; determining a threat level as a function of the first vehicle trajectory and the road condition signal; and activating a counter-measure system in response to the threat level. 
     Other aspects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a block diagrammatic view of a pre-crash sensing system according to the present invention. 
     FIG. 2 is a block diagrammatic view of one embodiment of the invention illustrating a vehicle network established by two pre-crash sensing systems. 
     FIG. 3 is a perspective view of an automotive vehicle instrument panel display for use with the present invention. 
     FIG. 4 is a front view of a vehicle network display according to the present invention. 
     FIG. 5 is a front view of a warning display according to the present invention. 
     FIG. 6 is a counter-measure display according to the present invention. 
     FIG. 7 is a flow chart of the operation of a pre-crash sensing system according to the present invention. 
    
    
     DETAILED DESCRIPTION 
     In the following figures the same reference numerals will be used to identify the same components in the various views. 
     Referring now to FIG. 1, a pre-crash sensing system  10  for an automotive vehicle  11  has a controller  12 . Controller  12  is preferably a microprocessor-based controller that is coupled to a memory  14 . Controller  12  has a CPU  13  that is programmed to perform various tasks. Memory  14  is illustrated as a separate component from that of controller  12 . However, those skilled in the art will recognize that memory may be incorporated into controller  12 . 
     Memory  14  may comprise various types of memory including read only memory, random access memory, electrically erasable programmable read only memory, and keep alive memory. Memory  14  is used to store various thresholds and parameters including vehicle data  16  as illustrated. 
     Controller  12  is coupled to a global positioning system  18  that receives position data triangulated from satellites as is known to those skilled in the art. 
     Controller  12  is coupled to a sensor data block  20  that represents various sensors located throughout the vehicle. The various sensors will be further described below. 
     Controller  12  may also be coupled to a receiver  22  coupled to a receiving antenna  24  and a transmitter  26  coupled to a transmitting antenna  28 . 
     Controller  12  is also coupled to a display  30  that may include various types of displays including a vehicle network display, a warning display  34 , and a counter-measure display  36 . Each of these displays will be described in further detail below. As should be noted, display  30  may be a single display with different display features or may be individual displays that may include audible warnings as well. 
     Controller  12  has various functional blocks illustrated within CPU  13 . Although these functional blocks may be represented in software, they may also be illustrated in hardware. As will be further described below, controller  12  has a proximity detector  42  that is used to determine the proximity of the various vehicles around automotive vehicle  11 . A vehicle trajectory block  44  is used to determine the trajectory of the vehicle and surrounding vehicles. Based upon the vehicle trajectory block  44 , a threat assessment is made in functional block  46 . Of course, threat assessment  46  takes into consideration various vehicle data  16  and sensor data from sensor block  20 . Threat assessment  46  may be made based upon the braking capability of the present vehicle and surrounding vehicles in block  48  and also road conditions of the present vehicle and surrounding vehicles in block  50 . As will be further described below, the road conditions of block  50  may be used to determine the braking capability in block  48 . 
     In block  16 , various vehicle data are stored within the memory. Vehicle data represents data that does not change rapidly during operation and thus can be fixed into memory. Various information may change only infrequently and thus may also be fixed into memory  14 . Vehicle data includes but is not limited to the vehicle type, which may be determined from the vehicle identification number, the weight of the vehicle and various types of tire information. Tire information may include the tire and type of tread. Such data may be loaded initially during vehicle build and may then manually be updated by a service technician should information such as the tire information change. 
     Global positioning system (GPS)  18  generates a position signal for the vehicle  11 . Global positioning system  18  updates its position at a predetermined interval. Typical interval update periods may, for example, be one second. Although this interval may seem long compared to a crash event, the vehicle position may be determined based upon the last up update from the GPS and velocity and acceleration information measured within the vehicle. 
     Sensor data  20  may be coupled to various sensors used in various systems within vehicle  11 . Sensor data  20  may include a speed sensor  56  that determines the speed of the vehicle. Speed sensor may for example be a speed sensor used in an anti-lock brake system. Such sensors are typically comprised of a toothed wheel from which the speed of each wheel can be determined. The speed of each wheel is then averaged to determine the vehicle speed. Of course, those skilled in the art will recognize that the vehicle acceleration can be determined directly from the change in speed of the vehicle. A road surface detector  58  may also be used as part of sensor data  20 . Road surface detector  58  may be a millimeter radar that is used to measure the road condition. Road surface detector  58  may also be a detector that uses information from an anti-lock brake system or control system. For example, slight accelerations of the wheel due to slippage may be used to determine the road condition. For example, road conditions such as black ice, snow, slippery or wet surfaces may be determined. By averaging microaccelerations of each tire combined with information such as exterior temperature through temperature sensor  60 , slippage can be determined and therefore the road conditions may be inferred therefrom. Such information may be displayed to the driver of the vehicle. The surface conditions may also be transmitted to other vehicles. 
     Vehicle data  16  has a block  52  coupled thereto representing the information stored therein. Examples of vehicle data include the type, weight, tire information, tire size and tread. Of course, other information may be stored therein. 
     Sensor data  20  may also include a tire temperature sensor  62  and a tire pressure sensor  64 . The road condition and the braking capability of the vehicle may be determined therefrom. 
     Other system sensors  66  may generate sensor data  20  including steering wheel angle sensor, lateral acceleration sensor, longitudinal acceleration sensor, gyroscopic sensors and other types of sensors. 
     Referring now to FIG. 2, vehicle  11  may be part of a network  70  in conjunction with a second vehicle or various numbers of vehicles represented by reference numeral  72 . Vehicle  72  preferably is configured in a similar manner to that of vehicle  11  shown in FIG.  1 . Vehicle  72  may communicate directly with vehicle  11  through transmitter  26 ′ and receiver  22 ′ to form a wireless local area network. The network  70  may also include a repeater  74  through which vehicle  11  and vehicle  72  may communicate. Repeater  74  has an antenna  76  coupled to a transmitter  78  and a receiver  80 . Various information can be communicated through network  70 . For example, vehicle data, position data, and sensor data may all be transmitted to other vehicles throughout network  70 . 
     Referring now to FIG. 3, an instrument panel  82  is illustrated having a first display  84  and a second display  86 . Either displays  84 ,  86  may be used generate various information related to the pre-crash sensing system. 
     Referring now to FIG. 4, display  84  is illustrated in further detail. Display  84  corresponds to the vehicle network display  32  mentioned above. The vehicle network display  32  may include a map  88 , a first vehicle indicator  90 , and a second vehicle indicator  92 . First vehicle indicator corresponds to the vehicle in which the pre-crash sensing system is while vehicle indicator  92  corresponds to an approaching vehicle. Vehicle network display  32  may be displayed when a vehicle is near but beyond a certain distance or threat level. 
     Referring now to FIG. 5, display  84  showing a warning display  34  is illustrated. Warning display  34  in addition to the display information shown in vehicle network display in FIG. 3, includes a warning indicator  94  and a distance indicator  96 . Distance indicator  96  provides the vehicle operator with an indication of the distance from a vehicle. The warning display  34  may be indicated when the vehicle is within a predetermined distance or threat level more urgent than that of vehicle network display  32  of FIG.  3 . 
     Referring now to FIG. 6, vehicle display  84  changes to a counter-measure display  36  to indicate to the vehicle operator that a counter-measure is being activated because the threat level is high or the distance from the vehicle is within a predetermined distance less than the distances needed for activation of displays shown in FIGS. 3 and 4. 
     Referring now to FIG. 7, a method for operating the pre-crash sensing system is described. In step  100 , the various sensors for the system are read. In step  102 , various vehicle data is read. In step  104 , a first global positioning signal is obtained for the vehicle. In step  106 , the information from a second vehicle is obtained. The second vehicle information may be various information such as the speed, heading, vehicle type, position, and road conditions from the other vehicles or vehicle in the network. In step  108 , the proximity of the first vehicle and second vehicle is determined. The proximity is merely a distance calculation. In step  110 , the first vehicle trajectory relative to the second vehicle is determined. The first vehicle trajectory uses the information such as the positions and various sensors to predict a path for the first vehicle and the second vehicle. In step  112 , the threat of the first vehicle trajectory relative to the second vehicle is determined. For example, when the first vehicle may collide with the second vehicle, a threat may be indicated. The threat is preferably scaled to provide various types of warning to the vehicle. Threat assessment may be made based upon conditions of the vehicle trajectory and vehicle type as well as based upon tire information which may provide indication as to the braking capability of the first vehicle and/or the second vehicle. Thus, the threat may be adjusted accordingly. Also, the road surface condition may also be factored into the threat assessment. On clear dry roads a threat may not be as imminent as if the vehicle is operating under the same conditions with wet or snowy roads. In the previous blocks, it should be noted that the system is not activated until a vehicle is within a predetermined distance. The threat assessment, it should be noted, is based on a ballistic trajectory such as that described in  44  above in FIG.  1 . If the threat is not less than a predetermined threshold or the distance is greater than the predetermined threshold, a first display is presented to the driver in step  116 . The first display generated in step  116  may, for example, correspond to the vehicle network display shown in FIG.  3 . If the threat is less than a first threshold, then a second display such as warning display  34  shown in FIG. 4 may be generated in step  118 . Step  118  may for example be presented to the driver when the vehicle is within a predetermined distance from the first vehicle. In step  120 , if the threat is not less than a second threshold step  100  is performed. If the threat is less than a second threshold or the second vehicle is closer to the first vehicle (below the second threshold), then a counter-measure display  36  such as that shown in FIG. 6 may be presented to the vehicle operator in step  122 . The counter-measure may also then be activated in step  124 . Various counter-measures may include front or side airbag deployment, activating the brakes to lower the front bumper height, steering or braking activations. 
     As would be evident to those skilled in the art, various permutations and modifications to the above method may be performed. For example, a system in which the road condition and position of the second vehicle may be used t o activate a counter-measure system may be employed. Likewise, the second vehicle position relative to the first vehicle and the road condition at the second vehicle may also be displayed to the vehicle operator. Likewise, the threat assessment may also be adjusted according to the road condition. 
     Another embodiment of the present invention includes activating the counter-measure system in response to the braking capability of surrounding vehicles. By factoring in the braking capability of surrounding vehicles, threat assessment levels may be adjusted accordingly. Likewise, the braking capability of the first vehicle may also be used in the threat assessment level. Likewise, the displays may also be updated based upon the braking capabilities of the nearby vehicles. The braking capabilities may be determined from various tire type, size, tread, tire pressure, tire temperature, outside temperature as well as the road condition. 
     Advantageously, by connecting the vehicles through the network, various information may be known to drivers of other nearby vehicles. For example, the presence of black ice and other slippery conditions not readily apparent may be transmitted to other vehicles for avoidance thereof. 
     While particular embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims.