Abstract:
A damage detection system includes a processor and a transmitter communicatively connected to the processor. The transmitter sends a signal to the processor and the processor is programmed to assign a spatial coordinate to the transmitter. The processor is further programmed to identify a transmitter location as damaged when the transmitter fails to send the signal. The damage detection system may analyze the damaged area and report potentially affected sub-systems to users of a machine or vehicle equipped with the damage detection system.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention is generally directed to damage detection and evaluation systems, and, more particularly to aircraft damage detection and evaluation systems that use a plurality of wireless transmitters.  
         [0003]     2. Background Description  
         [0004]     Identification of damaged locations in a system or on a vehicle is commonly dependent upon operator perception and analysis. Often, an operator is unable to adequately perceive the entire damaged location due to dynamic system movement or limited field of vision. For example, a machine operator may not be able to see a portion of the machine because it may be blocked by other parts of the machine or workers. Additionally, poor lighting may contribute to inadequate perception of the operator.  
         [0005]     Quite often, the operator must rely on sensors for secondary systems or subsystems to obtain information relating to possible system damage. For example, a machine may have a sensor that reports hydraulic pressure available. When the available hydraulic pressure drops below a normal operating pressure, the operator may know that there is a malfunction or damage in the hydraulic system. Of course, sensors for other subsystems may include, but are not limited to, electrical systems, pneumatic systems, navigation systems, etc.  
         [0006]     Systems that are particularly susceptible to this type of problem include vehicles, and specifically include aircraft. Often a pilot of an aircraft is confined to a cockpit area that has a limited field of view. The pilot must rely almost exclusively on instrument readings that are reported to the cockpit. However, the pilot may also perceive vibrations through the aircraft. Should an aircraft be involved in a collision, with a bird for example, the pilot may not be able to ascertain the full extent of damage to the aircraft until after landing. This is often too late.  
         [0007]     Aircraft are generally designed with certain safety features that may isolate aircraft systems in the case of an emergency. However, the pilots often have no indication of potential system failure due to aircraft damage until system resources are depleted. For example, during combat, small arms fire may be a threat to the aircraft. If a bullet pierces the body of the aircraft and damages a hydraulic line thereby creating a small leak in the hydraulic system, the pilot may have no indication of the damage for several minutes or longer. During this time, the hydraulic system may be losing hydraulic fluid and the fluid may not be replaceable. Eventually, the hydraulic system may be depleted of fluid potentially causing even more serious problems. However, if the pilot were aware of the slow leak, the pilot may be able to isolate a portion of the hydraulic system that includes the leak, thus preserving the hydraulic fluid for the rest of the hydraulic system.  
         [0008]     One well known incident involved a commercial aircraft crash at Sioux City Iowa. In this incident, an engine failure ruptured lines of all three hydraulic systems causing a total loss of hydraulic pressure to the aircraft. Had the pilots been aware of the damage to the hydraulic systems soon after the failure of the engine, they may have been able to isolate the damaged area before the total failure of the hydraulic system.  
         [0009]     The present invention is directed to overcoming one or more of the problems or disadvantages associated with the prior art.  
       DISCUSSION OF RELATED ART  
       [0010]     Systems have been developed which sense positions of certain components. For example, a method of sensing position for a workpiece and a tool that performs a manufacturing operation on the workpiece is disclosed in U.S. patent application Ser. No. 11/096,612, assigned to The Boeing Company, the entirety of which is hereby incorporated by reference. This method includes measuring at least three discrete point positions associated with a first component by using a transmitter having a known position and orientation and in a line of sight with the three distinct point positions. The three distinct point positions have known distances relative to one another. The method computes a current position and orientation of the first component using data provided by the transmitter and the three distinct point positions, along with position and orientation data from a last known location of the first component. The method assumes no sudden position changes for the first component. While this method tracks and senses position of certain components, the method does not detect or analyze damaged locations.  
       SUMMARY OF THE INVENTION  
       [0011]     A damage detection system is described herein that includes a processor and at least one transmitter communicatively connected to the processor. The transmitter sends a signal to the processor and the processor may be programmed to assign a spatial coordinate to the transmitter. The processor may be further programmed to identify a transmitter location as damaged when the transmitter fails to send the signal.  
         [0012]     A method of identifying a damaged location is also described herein. The method includes attaching a plurality of remotely powered transmitters to a vehicle, and each of the plurality of transmitters is adapted to send a signal to a processor. The method may further include providing remote power to the plurality of transmitters, thereby causing each of the plurality of transmitters to send the signal to the processor. The processor may then assign spatial coordinates to each of the plurality of transmitters and may monitor the plurality of transmitters to identify non-functioning transmitters. The processor may determine a damaged location by identifying an area of the vehicle based upon the spatial coordinates assigned to any non-functioning transmitter.  
         [0013]     The features, functions, and advantages can be achieved independently in various embodiments of the present invention or may be combined in yet other embodiments. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a side view of an exemplary aircraft;  
         [0015]      FIG. 2 , is a top perspective view of the aircraft of  FIG. 1  showing locations of a plurality of remote transmitters which comprise a damage detection system;  
         [0016]      FIG. 3  is a schematic diagram of the damage detection system of  FIG. 2 ; and  
         [0017]      FIG. 4  is an example of tabulated data that may be compiled by the damage detection system of  FIG. 3 . 
     
    
     DETAILED DESCRIPTION  
       [0018]     Damage detection systems may be employed on vehicles such as an aircraft. However, damage detection systems, such as the systems disclosed herein, can easily be adapted for use on any type of vehicle, for example, a car, a truck, a tank, a submarine, an airship, a space vehicle, a ship, or virtually any other type of vehicle. Such damage detection systems may be especially useful for combat aircraft.  
         [0019]     As shown in  FIG. 1 , an aircraft  10  generally includes a cockpit or flight deck  12  from which one or more pilots controls the aircraft  10 . Often, the pilot&#39;s view of the aircraft  10  is obscured by the body  14  of the aircraft  10 . Accordingly, the pilot is unable to view large portions of the aircraft  10 , for example, the underside of the wings  16 , the landing gear  18 , and/or the empennage  20 . As a result, the pilots must rely on system instrumentation indications, such as hydraulic pressure, electrical volts and amperes, pneumatic pressures, etc., to alert the pilots to potential damage on the aircraft  10 . The aircraft  10  in  FIG. 1  is shown as an example of a vehicle that may use the damage detection system. Virtually any vehicle could use such a system, for example, automobiles, ships, submarines, helicopters, trucks, earth moving equipment, spacecraft, etc.  
         [0020]      FIG. 2  shows the aircraft of  FIG. 1  having a damage detection system. The damage detection system includes a processor  30  located in the aircraft  10  and a plurality of transmitters  32  arranged on the aircraft  10  at various locations. While  FIG. 2  shows only certain locations having transmitters  32 , the entire aircraft  10  could be substantially covered with such transmitters  32 . Additionally, transmitters  32  may be located at certain critical locations within the body of the aircraft  10  itself to enhance early detection of damage to internal aircraft systems. The transmitters  32  may communicate with the processor  30  by sending a coded signal to the processor  30  continuously or periodically. The processor  30  may be programmed to decode the signal and determine the location of the transmitter  32  that sent the signal. The processor  30  may monitor all of the transmitters  32  and if a transmitter  32  fails to send the expected signal, the processor  30  may alert the pilot and identify the location of the transmitter  32  as a damaged location. The processor  30  may also determine if the transmitter  32  is simply malfunctioning, in which case, the processor  32  may simply remove the transmitter  32  from the system. As shown in  FIG. 2 , the damage detection system may allow the pilots to monitor the entire aircraft  10  without needing the ability to visually observe each part of the aircraft  10 .  
         [0021]      FIG. 3  shows a schematic view of the damage detection system. Each of the transmitters  32  transmits a signal to the processor  30 . In one embodiment, the transmitters  32  first transmit the signal to a node  34  which summarizes signal data from a group  36  of transmitters  32 . The transmitters  32  may be assigned to certain groups  36  based on location or based on system type. For example, transmitters  32  placed on a wing structural component may be assigned to one group while transmitters  32  inside the wing on a hydraulic line may be assigned to another group. The nodes  34  may act as intermediaries between the transmitters  32  and the processor  30 . This arrangement of nodes  34  may speed up transmission of the signals and may minimize processing time to analyze the signals.  
         [0022]     The transmitters  32  preferably communicate with the processor  30  wirelessly. However, the transmitters  32  could be wired to the processor  30  if desired. Additionally, where nodes  34  are employed, the transmitters  32  preferably communicate wirelessly with the node  34  which in turn communicates wirelessly with the processor  30 . However, in certain locations, it may be advantageous for the transmitters  32  to be wired to the node  34 .  
         [0023]     The transmitters  32  may either generate power internally, or rely on an excitement signal for power. For example, the transmitters  32  may be piezo-electric in nature and generate power from vibrations of the aircraft  10 . In one embodiment, the piezo-electric transmitters may be chips that generate approximately 100 microcoulombs of electricity which may be stored temporarily in a capacitor. This amount of power is sufficient to generate and transmit the signal to the processor  30 . Because an aircraft, or any vehicle, constantly generates vibrational energy, a virtually endless energy supply exists for the transmitters  32 .  
         [0024]     In another embodiment, the transmitters  32  may be radio frequency stimulated (e.g., RFID tags). The processor  30  may send out a radio frequency signal to the transmitters  32  which reflect back a signal to the processor  30 . This arrangement is especially desirable for combat aircraft where the pilot may select a scanning time based on potential threats. For example, the pilot may only scan the aircraft  10  on egress after a mission to avoid potential detection by enemy anti-aircraft systems.  
         [0025]     A wireless system is much lighter than a like wired system. Thus a wireless system is desirable over a wired system for an aircraft  10  because any reduction in empty weight of an aircraft  10  results in a corresponding increase in payload available. Furthermore, should one transmitter  32  fail, there is no doubt as to whether the transmitter  32  itself failed or the wiring between the transmitter and the processor has broken because there is no wire to break. Moreover, such wireless systems are very easily scaled and adaptable. For example, if an external fuel tank is added to an aircraft after an initial production, one or more transmitters  32  may simply be added to the external fuel tank and the programming of the processor  30  updated accordingly. Similar modifications could be made to the wireless system after repair or replacement of a component of after a rebuild of the wireless system.  
         [0026]     Other means of powering the transmitters may exist, for example, solar power or wind power. The means of powering the transmitters  32  is not limiting so long as the transmitters  32  are able to transmit the signal to the processor  30 . Additionally, while one embodiment of the damage detection system may use power scavenging chips as transmitters, the transmitters are not limited to a chip-like configuration and could vary widely in size and shape as long as the transmitters are able to send a signal to the processor.  
         [0027]      FIG. 4  shows an example of data that may be generated by the processor  30  in response to signals sent from the transmitters  32 . The data is only shown in table form for ease of reading and explanation. The processor  30  does not actually need to tabulate the data before analysis.  
         [0028]     The table  100  includes several columns of information. The first column  110  shows an identification number assigned to the individual transmitter  32 . The second column  112  shows a System ID, which corresponds to a particular aircraft system to which the transmitter  32  is assigned. For example, the System ID of “1000” shown in the figure may correspond to a structural member, such as a wing, tail, fuselage, etc. Other systems can be identified as well, for example, a System ID of “2000” may correspond to an engine, a System ID of “3000” may correspond to the hydraulic system, a System ID of “4000” may correspond to the electrical system, etc. Of course this labeling system allows for various sub-system identifiers as well. For example, a System ID of “2100” may correspond to the #1 engine, and a System ID of “2110” may correspond to the fuel control unit of the #1 engine. The System ID&#39;s may be kept very general or be made extremely specific based on user requirements, the complexity of the aircraft or vehicle and/or the number of transmitters employed in the system.  
         [0029]     Columns  114 - 118  show the X, Y, and Z spatial coordinates assigned to the transmitter  32 . These spatial coordinates may be assigned to the transmitter  32  at installation by exciting the system and recording the location of each transmitter  32  based on a reference location. Thereafter, the processor  30  is able to correlate a particular spatial coordinate to a particular location on the aircraft or vehicle. The Assigned Size column  120  shows how large an area is assigned to each transmitter  32 . The assigned size may depend on the proximity of other transmitters  32 . For example, transmitters  32  that are placed  1  inch apart may be assigned a size of one inch square. The Transmitting column  122  simply shows whether the particular transmitter  32  is sending the processor  30  a signal.  
         [0030]     The Damage Data table  130  shows a summary of data for a non-functional transmitter  32 . The non-functional transmitter&#39;s  32  spatial coordinates are shown in columns  132 - 136 . The processor may be programmed to identify the area bounded by the spatial coordinates in columns  132 - 136  as the damaged area. The system column  138  shows that this particular transmitter  32  was assigned to a structure group meaning that the transmitter  32  was attached to a structure of the aircraft  10  as opposed to a sub-system. The information in column  138  corresponds to the System ID information of column  112  of table  100 . The size column  140  shows that the area assigned to this particular transmitter is 0.1 inches square. The information from the Damage Data table  130  may be available to the processor  30  for further analysis.  
         [0031]     The processor  30  may be programmed to analyze the data from the Damage Data table  130  for assessing structural integrity of the aircraft  10 . After identifying the damage area, the processor may compare the damage area to structural information about the aircraft  10  and the processor  30  may determine whether the aircraft  10  remains airworthy based on the location and size of the damaged area. For example, should the size and location of the damage area indicate that a wing spar can no longer support its design load, the aircraft  10  should be subjected to only limited maneuvering until an appropriate repair is made. The processor  30  may further analyze the damage location to determine whether any sub-systems may be affected. For example, should the damage area be in the vicinity of a hydraulic line, the processor  30  may prompt the pilot to accomplish a particular checklist or to isolate the hydraulic system in the vicinity of the damage area if possible.  
         [0032]     Should the damage detection system determine that a critical sub-system is located in the damage area, the processor  30  may immediately notify the pilot (or vehicle operator) through some sort of alert system, e.g., visual or aural alerts in the cockpit. The pilot may then take appropriate action based on the possible loss of the critical sub-system.  
         [0033]     The processor  30  may be further programmed to infer potentially affected sub-systems or components based on two separate damage areas. For example, a projectile may enter a bottom portion of a wing and exit through a top portion of the wing. Should the damage detection system only have transmitters  32  disposed on the outer surfaces of the aircraft, the processor  30  may interpolate between the upper and lower damage locations to determine whether any sub-systems within the wing structure may have been damaged.  
         [0034]     The damage detection system disclosed herein requires very little processing power due to the fact that only a limited amount of data is required for transmission. Each of the transmitters  32  may essentially send an identity code that can be a single number, and the processor  30  has stored the location and system data assigned to each particular transmitter  32 . Data storage requirements for such a system are small as well. This limited amount of data also enables very fast processing times and simple programming for cross-referencing of each transmitter  32 . As a result, damage detection systems described herein are relatively inexpensive and very light weight.  
         [0035]     Additionally, the processor  30  may transmit the damage data to a ground station for further analysis. As a result, a maintenance technician may have access to the damage data and may recommend actions or procedures in addition to the actions and procedures recommended by the on-board damage detection system. Furthermore, the maintenance personnel may have additional time to prepare for potential repairs to the aircraft  10  before the aircraft  10  arrives at a maintenance station, thus saving valuable time and enabling a faster repair of the aircraft  10 . This ability may prove critical in a war fighting situation.  
         [0036]     Still further, based on the downloaded damage data, maintenance personnel may be able to determine an ideal repair facility to direct the aircraft  10  to should repair facilities with different capabilities be available. For example, if two repair facilities are available, but only one has a sheet metal shop, an aircraft with sheet metal damage should be directed to this particular repair facility if it is safe to do so.  
         [0037]     Installations of such damage detection systems are simple as well. As transmitter sizes get smaller in response to technological advances, several application techniques may be available such as using light-duty adhesive bonding, for example. Furthermore, the transmitters  32  may be individually attached to the aircraft with an adhesive, or for smaller transmitter sizes, via brushing, spraying or spreading the transmitters over the selected surface. Moreover, the transmitters  32  may be integrated into the structures during fabrication of the structures. For example, the transmitters  32  may be mixed with or bonded into raw material prior to forming a particular structural element, such as a wing or a tail. For example, the transmitters  32  may be bonded between layers of a laminated structural element.  
         [0038]     As a result, certain areas of the aircraft may be targeted for the transmitters  32 . For example, only critical flight surfaces may be integrated in an effort to reduce cost and weight. Furthermore, a malfunctioning transmitter  32  may be “locked out” of the system. In other words, malfunctioning transmitters  32  may simply be ignored by the processor  30 . Additionally, malfunctioning transmitters are easily replaced because the processor need only be updated to recognize the identity of each new transmitter  32 . The spatial coordinates of the old transmitter  32  may then simply be assigned to the new transmitter  32 .  
         [0039]     Once the damage detection system has identified the damage area, this information may be sent to other aircraft systems for further analysis. For example, the damage area information may be sent to the fuel management system which may account for extra drag associated with the damage area. As a result, the navigation system may update the maximum range of the aircraft  10  and inform the pilot if the original destination is unreachable with the added drag.  
         [0040]     Other aspects and features of the present invention can be obtained from a study of the drawings, the disclosure, and the appended claims.