Patent Publication Number: US-2016221663-A1

Title: Flight control computer for an aircraft that includes an inertial sensor incorporated therein

Description:
TECHNICAL FIELD 
     Embodiments of the present invention generally relate to aircraft, and more particularly relate to a flight control computer for an aircraft that includes inertial sensor(s) integrated within the flight control computer. 
     BACKGROUND OF THE INVENTION 
     Modern aircraft are often equipped with a flight control computer that is part of a “fly-by-wire” control system. In a typical, fly-by-wire airplane, electronic sensors are attached to the pilot&#39;s controls. These sensors transmit electronic data to various flight control computers. Actuator control electronics receive the electronic signals from the flight control computer and move hydraulic actuators based on the received signals. For example, each hydraulic actuator is coupled to a moveable surface such that movement of the actuator moves the primary control surface. The fly-by-wire concept results in a savings of weight as there is no longer a need for heavy linkages, cables, pulleys, and brackets running throughout the airplane to control the actuators, only electrical wiring to the flight control computer and the actuator control electronics. Furthermore, this concept may result in a smoother flight, with less effort needed by the pilot. 
     Many newer aircraft also employ an integrated air data inertial reference system (ADIRS). Some ADIRS can include air data inertial reference units (IRUs) located in the aircraft. 
     Each air data inertial reference unit (IRU) includes air data reference (ADR) components and an inertial reference (IR) components that each include a variety of different sensors and devices used to acquire information that can be used to determine/compute airspeed, Mach number, angle of attack, temperature and barometric altitude data, attitude, flight path vector, ground speed and positional data, etc. The ADR components can supply information about air data (e.g., airspeed, angle of attack and altitude), and the IR components can supply inertial reference information (e.g., position and attitude). This information can be provided to the pilots&#39; electronic flight instrument system displays, as well as to other systems on the aircraft such as the engine electronic control computers, autopilot computers, flight control computers, landing gear systems, etc. 
     As such, aircraft that implement fly-by-wire systems include a number of different sensors that are located throughout the aircraft. For safety reasons, it is often preferable to include redundant versions of these sensors in case they are needed. This not only requires additional sensors mounted throughout the aircraft, but also wired connections between these redundant sensors, the flight control computer and power supplies for the redundant sensors. 
     There is a need for an aircraft that includes a low cost avionics system with redundant sensors. It would be desirable to eliminate at least some of the wiring needed in such an avionic system. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background. 
     SUMMARY 
     The disclosed embodiments relate to an aircraft and a flight control computer that can be used in the aircraft. The flight control computer includes at least one inertial sensor that is incorporated or integrated within the flight control computer. For instance, in one implementation, the inertial sensor can be integrated within a processor of the flight control computer. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
         FIG. 1  is a perspective view of an aircraft in which the disclosed embodiments can be implemented in accordance with one non-limiting implementation. 
         FIGS. 2A through 2C  are front, side and top perspective views, respectively, of an aircraft in which the disclosed embodiments can be utilized in accordance with one non-limiting implementation. 
         FIG. 3  is a block diagram of an aircraft avionics and fly-by-wire flight control system that includes a flight control computer in accordance with an exemplary implementation of the disclosed embodiments. 
         FIG. 4  is a block diagram of a flight control computer in accordance with one exemplary implementation of the disclosed embodiments. 
         FIG. 5  is a block diagram of a flight control computer having a processor with integrated sensors in accordance with other disclosed embodiments. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in this Detailed Description are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following description. 
     The disclosed embodiments relate to a flight control computer that includes inertial sensor(s) integrated within the flight control computer. The inertial sensor(s) can be, for example, sensors such as accelerometer(s) and/or gyroscope(s). In one implementation, the inertial sensor(s) can be integrated within a processor of the flight control computer. The inertial sensor(s) can generate inertial signal data that can be processed by the processor to generate control commands that are used to control flight control surfaces of the aircraft. The disclosed embodiments can eliminate the need for separate wired connections that are normally needed between the flight control computer and inertial sensor(s), and between the power supply and the inertial sensor(s). The inertial sensor(s) can be redundant versions of external inertial sensor(s) that are coupled to the flight control computer via wired connections. This way, when inertial sensor data is unavailable from the external inertial sensor(s), the inertial sensor(s) that are integrated within the flight control computer can be used as a backup to generate control commands that can be used, for example, to control flight control surfaces of the aircraft. 
       FIG. 1  is a perspective view of an aircraft  10  in which the disclosed embodiments can be implemented in accordance with one exemplary, non-limiting implementation.  FIGS. 2A through 2C  are front, side and top perspective views, respectively, of an aircraft  10  in which the disclosed embodiments can be implemented in accordance with one exemplary, non-limiting implementation.  FIGS. 2A through 2C  show three axes about which an aircraft  10  can be controlled. 
     In accordance with one non-limiting implementation of the disclosed embodiments, the aircraft  10  includes fuselage  110 , which holds the passengers and the cargo; two main wings  112 , which provide the lift needed to fly the aircraft  10 ; a vertical stabilizer  114  and two horizontal stabilizers  116 , which are used to ensure a stable flight; and two jet engines  118 , which provide the thrust needed to propel the aircraft  10  forward. Flight control surfaces are placed on wings  112 , horizontal stabilizers  116 , and vertical stabilizers  114  to guide the aircraft  10 . Flight control surfaces can include primary and secondary flight control surfaces. 
     The primary flight control surfaces include the ailerons  100  located on the trailing edges of the wings of the aircraft  10 , the elevators  102  located on the horizontal stabilizer of an aircraft  10 , and the rudder  104  located on the vertical stabilizer. The primary flight control surfaces are operated by a pilot located in the cockpit of the aircraft  10 . The ailerons  100  control the roll of the aircraft  10 . The ailerons  100  can be controlled, for example, by adjusting a control yoke to the left or right. For example, moving the control yoke to the left typically controls the left aileron to rise and the right aileron to go down, causing the aircraft  10  to roll to the left. Rolling of an aircraft  10  is depicted in  FIG. 2A . The elevators  102  control the pitch of the aircraft  10 . The elevators  102  can be controlled, for example, by adjusting a control yoke to the front or back. Pitching of an aircraft  10  is depicted in  FIG. 2B . The rudder  104  controls the yaw of the aircraft  10 . The rudder  104  can be controlled, for example, by a pair of rudder pedals operated by the pilot&#39;s feet. Yawing of an aircraft  10  is illustrated in  FIG. 2C . 
     The secondary flight control surfaces can include spoilers  119  and flaps  120  on the wings  112  of the aircraft  10 . Flaps  120  are provided at the trailing edges of wings  112 . Spoilers  119  perform a variety of different functions, including assisting in the control of vertical flight path, acting as air brakes to control the forward speed of the aircraft  10 , and acting as ground spoilers to reduce wing lift to help maintain contact between the landing gear and the runway when braking. Flaps  120  change the lift and drag forces effecting an aircraft  10 . When flaps  120  are extended the shape of the wing changes to provide more lift so that the aircraft  10  is able to fly at lower speeds, thus simplifying both the landing procedure and the take-off procedure. 
     Although not shown in  FIG. 1 , the aircraft  10  also includes various onboard computers, aircraft instrumentation and various control systems. These onboard computers can include flight control computers and the aircraft instrumentation can include various sensors that make up portions of an avionics system as will now be described with reference to  FIG. 3 . 
       FIG. 3  is a block diagram of an aircraft avionics and fly-by-wire flight control system that includes a flight control computer  212  in accordance with an exemplary implementation of the disclosed embodiments. 
     The system  200  comprises a flight control system (FCS)  210 , an actuator control unit  214 , actuators  216 , various flight control surfaces  218 , at least one Inertial Reference Unit (IRU)  220 , at least one Attitude Heading Reference System (AHRS)  230 , other sensors  240 , and a pilot input system  250 , and a power supply that supplies power via wired connections to at least the FCS  210 , the IRU  220 , the AHRS  230 , and the other sensors  240 . The system  200  can also include other elements including flight displays, etc. that are not illustrated for sake of simplicity. Although not illustrated, it will be appreciated that an aircraft can include any appropriate number of redundant avionics systems or any number of the sub-systems that make up the avionics system  200 . 
     The IRU  220  includes devices, components and sensors such as gyroscope(s) (e.g., ring laser gyroscope(s)), accelerometer(s), Global Position System (GPS) receiver(s), and other motion sensor devices). For example, the IRU  220  can include ring laser gyroscope(s) and accelerometer(s) that can sense information that can be used to compute or generate inertial signal data  222  that is provided to the flight control system  210 . The inertial signal data  222  can generally include inertial flight data such as angular rates of the aircraft rates (e.g., angular rates of roll, pitch and yaw axes) and linear accelerations, as well as the aircraft attitude and velocity. 
     Like the IRU  220 , the AHRS  230  includes sensor devices such as gyroscopes, accelerometers and/or magnetometers that are not illustrated for sake of simplicity. The AHRS  230  also includes a processor and software for processing information from the various sensor devices to generate inertial flight control data  232  that it provides to the flight control system  210  and its flight control computer  212 . For example, in some implementations, the AHRS  230  includes three sensors for the three axes of the aircraft that can provide heading, attitude and yaw measurement data for each of the three axes of the aircraft. This heading, attitude and yaw measurement data can processed via a processor at the AHRS  230  to provide the inertial flight control data  232  (e.g., rates, accelerations, attitude and heading measurement data) directly to the flight control computer  212 . 
     Depending on the implementation, this inertial flight control data  232  can include at least some of the inertial signal data  222  that is described above with respect to the IRU  220 . As such, in some embodiments, the IRU  220  and the AHRS  230  output substantially similar types of data (e.g., rates, accelerations, attitude and heading measurements) to the flight control system  210  and its flight control computer  212 . In other words, the inertial signal data  222  and the inertial flight control data  232  are “redundant” to a certain extent. The inertial flight control data  232  from the AHRS  230  can be used to check or confirm the correctness of the inertial signal data  222  that is output by the IRU  220 . 
     The other sensors  240  can include, for example, air data sensors, air data reference (ADR) components or sensors, acoustic sensors (e.g., sound, microphone, seismometer, accelerometer, etc.), vibration sensors, aircraft sensors (e.g., air speed indicator, altimeter, attitude indicator, gyroscope, magnetic compass, navigation instrument sensor, speed sensors, angular rate sensor, etc.), position, angle, displacement, distance, speed, acceleration sensors (e.g., accelerometer, inclinometer, position sensor, rotary encoder, rotary/linear variable differential transformer, tachometer, etc.). The other sensors  240  can also include pitot and static pressure sensors that can be used to measure Ram air pressure and static pressures, and provide data or information that can be used to determine/compute airspeed, Mach number, angle of attack, temperature and barometric altitude data, etc. The other sensors  240  can also include Global Positioning System (GPS), Global Navigation Satellite System (GNSS), or other satellite based sensor systems. 
     The pilot input system  250  generates various pilot input signals in response to inputs from the pilot. The pilot input signals can be generated in response to the pilot adjusting a control stick to the left or right, adjusting a control wheel or control stick to the front or back, adjusting a rudder pedal, etc. 
     The flight control system  210  includes a flight control computer  212 . The flight control computer  212  receives pilot input signals  252  and based on these signals and other information generates engine control signals  219  that control the engines  118 , and control commands  213  that control the various flight control surfaces (e.g., ailerons  100 , elevators  102 , rudder  104 , spoilers  119 , flaps  120 ) of the aircraft. The flight control computer  212  is configured to operate the various flight control surfaces  218  on an aircraft by issuing control commands  213  to an actuator control unit  214  (or multiple actuator control units) that controls actuators  216  coupled to the various flight control surfaces  218  to provide a desired flight operation in response to various criteria. The flight control computer  212  can receive input signals  222 ,  232 ,  242  from the IRU  220 , the AHRS  230 , and other sensors  240 , respectively. Examples of input signals  222 ,  232  can include signals that provide information regarding rates (e.g., angular body rate signals), acceleration signals, altitude signals, attitude signals, speed signals, heading signals, etc. Input signals  242  from the other sensors can include various air data reference signals such as airspeed, altitude, and air temperature, as well as signals from any other type of sensors that are part of the aircraft. The flight control computer  212  also receives pilot input signals from the pilot input system  250 . 
     The flight control computer  212  processes the pilot input signals  252  and at least some of the input signals  222 ,  232 ,  242  to translate the pilot input signals into commands  213  for use by the actuator control unit  214 . Although  FIG. 3  illustrates a single flight control computer  212 , those skilled in the art will appreciate that this block can represent multiple flight control computers (not illustrated) that receive the various inputs  222 ,  232 ,  242 ,  252  and use these inputs to control one of the various flight control surfaces  218 . Likewise, there can be multiple actuator control units  216  that each control actuators associated with one of the various flight control surfaces  218 . 
     As described above with reference to  FIGS. 1 and 2 , the aircraft includes various primary flight control surfaces (e.g., one aileron  100  on each wing  112 , one elevator  102  on each horizontal stabilizer  116 , and one rudder  104  on the vertical stabilizer  114 ) and secondary flight control surfaces (e.g., spoilers  119 , flaps  120 , on the wings  112 ). Each flight control surface typically has one or more actuators for controlling its movement. The actuator control unit  214  transmits control signals  215  to actuators  216 . The actuators  216  generate signals  217  that control movement of the various flight control surfaces  218  of the aircraft in accordance with the control signals  215 . 
     In accordance with the disclosed embodiments, any of the various sensors that are described above can be incorporated or integrated within the FCC  212  as indicated by sensor block  260 . The sensors  260  incorporated or integrated within the FCC  212  can include sensors that are traditionally included to implement functions of the IRU  220 , the AHRS  230 , and the other sensors  240 . Depending on the implementation, the sensors  260  can be redundant meaning that they are included in addition to the various sensors that are described above as being implemented as part of the IRU  220 , the AHRS  230 , and the other sensors  240 , or can replace the various sensors that are described above as being implemented as part of the IRU  220 , the AHRS  230 , and the other sensors  240 . An example implementation of a flight control computer will now be described with reference to  FIG. 4 . 
       FIG. 4  is a block diagram of a flight control computer  212  in accordance with one exemplary implementation of the disclosed embodiments.  FIG. 4  will be described with reference to certain components described in conjunction with  FIG. 3 . 
     The flight control computer  212  includes a bus  305 , a processor  310 , a memory  315  that the processor  310  can access via a direct memory access bus  312 , input/output modules and interfaces  320 , and various sensors integrated within the flight control computer  212  including gyroscopes  332 , accelerometers  334 , magnetometers  336 , one or more GPS receiver(s)  338  and other sensors  340 . In some embodiments, the flight control computer  212  can also include wired and wireless communication interfaces (not illustrated) for communicating information with other systems onboard the aircraft  10  that are external to the flight control computer  212 . 
     The bus  305  can carry power, data, status, control and other information or signals between the various blocks of  FIG. 4 . Power can be supplied to the flight control computer  212  and all of its internal elements via a power supply  355  that can be external or internal to the flight control computer  212 , but is shown external to the flight control computer  212  in this particular embodiment. The bus  305  is used to carry information communicated between the processor  310 , the memory  315 , the gyroscopes  332 , the accelerometers  334 , the magnetometers  336 , the GPS receiver(s)  338 , the other sensors  340 , various sub-systems and aircraft instrumentation (not illustrated in  FIG. 4 ) that are external to the flight control computer flight control computer  212 , cockpit output devices (not illustrated in  FIG. 4 ), various input devices (not illustrated in  FIG. 4 ), and communication network interfaces (not illustrated in  FIG. 4 ). 
     The bus  305  can be implemented using any suitable physical and/or logical means of interconnecting the elements of the flight control computer  212  to at least the external and internal elements mentioned above. This includes, but is not limited to, direct hard-wired connections, fiber optics, and infrared and wireless bus technologies. Notably, the power supply  355  can supply power to the processor  310 , the memory  315 , the input/output modules and interfaces  320 , the gyroscopes  332 , the accelerometers  334 , the magnetometers  336 , the GPS receiver(s)  338 , and the other sensors  340  via the bus  305 . As such, the gyroscopes  332 , the accelerometers  334 , the magnetometers  336 , the GPS receiver(s)  338 , and the other sensors  340  do not need separate wired connections to the power supply  355 . Moreover, all of the connections between the bus  305  and the gyroscopes  332 , the accelerometers  334 , the magnetometers  336 , the GPS receiver(s)  338 , and the other sensors  340  are internal to the flight control computer  212 , which eliminates the need for external wiring that would normally be need between the flight control computer  212  and the gyroscopes, the accelerometers, the magnetometers, the GPS receiver(s), and any other sensors that are part of a IRU  220 , AHRS  230 , and other sensors  240  that the flight control computer  212  is connected to. 
     The processor  310  performs the computation and control functions of the flight control computer  212 , and may comprise any type of processor  310  (or multiple processors), single integrated circuits such as a microprocessor, or any suitable number of integrated circuit devices and/or circuit boards working in cooperation to accomplish the functions of a processing unit. The processor  310  can use the input/output modules and interfaces  320  to provide information to external computers and devices, and can receive information from external computers and devices. 
     The memory  315  may be a single type of memory component, or it may be composed of many different types of memory components. The memory  315  can includes non-volatile memory (such as ROM, flash memory, etc.), volatile memory (such as RAM), or some combination of the two. The RAM can be any type of suitable random access memory including the various types of dynamic random access memory (DRAM) such as SDRAM, the various types of static RAM (SRAM). The RAM can include an operating system and executable code for flight control programs executed by the processor  310 . The flight control programs (stored in system memory  315 ) that can be loaded via Direct Memory Access (DMA) bus  312  at the processor  310  and executed at processor  310  to implement various flight control functions. 
     The gyroscopes  332  can be the same or similar to those that are implemented as part of the IRU  220  and/or the AHRS  230 . The gyroscopes  332  measure the various angular velocities of the aircraft in the inertial reference frame, and can provide angular velocity signals  333  to the processor  310 . The aircraft&#39;s current orientation at any given time can be determined by using the original orientation of the aircraft in the inertial reference frame as an initial condition and integrating angular velocity. 
     The accelerometers  334  can be the same or similar to those that are implemented as part of the IRU  220  and/or the AHRS  230 . The accelerometers  334  measure the linear acceleration of the aircraft in the inertial reference frame in directions relative to the moving aircraft, and can provide linear acceleration signals  335  to the processor  310 . 
     The magnetometers  336  can be the same or similar to those that are implemented as part of the IRU  220  and/or the AHRS  230 . The magnetometers  336  can provide signals  337  that indicate the magnetic heading of the aircraft. 
     The GPS receiver(s)  338  can provide GPS signals  339  indicating the position and speed of the aircraft. 
     The other sensors  340  can include, without limitation, one or more of acoustic sensors (e.g., sound, microphone, seismometer, accelerometer, etc.), vibration sensors, air data sensors (e.g., air speed indicator, altimeter, attitude indicator, navigation instrument sensor, speed sensors, angular rate sensors, etc.), position, angle, displacement, distance, speed, acceleration sensors (e.g., inclinometer, position sensor, rotary encoder, rotary/linear variable differential transformer, tachometer, etc.) 
     The processor  310  receives the signals  333 ,  335 ,  337 ,  339  and  341  from the various gyroscopes  332 , accelerometers  334 , magnetometers  336 , GPS receiver(s)  338 , and other sensors  340 , and can process signals  333 ,  335 ,  337 ,  339  and  341  along with the pilot input signals  252  to translate the pilot input signals into engine control signals  219  and commands  213  for use by the actuator control unit(s)  214  to perform any of the flight control functions described above. For example, the processor  310  can perform processing that is the same or similar to that performed by the IRU  220  and/or the AHRS  230 . Among other things, the processor can use the current angular velocity signals  333  and the current linear acceleration signals  335  to determine the linear acceleration of the aircraft in the inertial reference frame, and the inertial accelerations can be used to determine the inertial velocities of the aircraft, and inertial position of the aircraft. 
       FIG. 5  is a block diagram of a flight control computer  512  having a processor  510  with integrated sensors in accordance with other disclosed embodiments.  FIG. 5  will be described with reference to certain components that are already described above in conjunction with  FIG. 4  and for sake of brevity the description of those components will not be repeated. In this implementation, various sensors are integrated within the processor  510  of the flight control computer  512 . These sensors can include gyroscopes  332 , accelerometers  334 , magnetometers  336 , GPS receiver components  338  and other sensors  340  that are integrated on and in the same die that the processor  512  is formed in and on. In one embodiment, the accelerometers  334 , magnetometers  336 , and other sensors  340  can be solid-state and/or microelectro-mechanical system (MEMS) devices. 
     In this embodiment, the gyroscopes  332 , the accelerometers  334 , the magnetometers  336 , the GPS receiver(s)  338 , and the other sensors  340  are part of the processor  510  and therefore do not need separate wired connections to the power supply  355 , but can instead use power provided to the processor  510  via the bus  305 . Moreover, there is not need for separate wired connections between the bus  305  and the gyroscopes  332 , the accelerometers  334 , the magnetometers  336 , the GPS receiver(s)  338 , and the other sensors  340  because those elements are internal to the processor  510 , which eliminates the need for external wiring that would normally be need between the flight control computer  212  and the gyroscopes, the accelerometers, the magnetometers, the GPS receiver(s), and any other sensors that are part of a IRU  220 , AHRS  230 , and other sensors  240  that the flight control computer  212  is connected to. 
     The disclosed embodiments can provide an aircraft with equal or better safety than those that utilize previous fly-by-wire systems. In the event that operation of one or more of primary sensors (e.g., one of the sensors at the IRU  220 , the AHRS  230 , and the other sensors  240 ) degrades, the outputs generated by sensors  260  can be used to generate appropriate control surface commands needed to achieve the desired aircraft motion and flight control. When the sensors  260  incorporated or integrated within the flight control compute  212  are implemented as redundant sensors, the disclosed embodiments can provide a fly-by-wire aircraft that is easier to design and that is less costly to manufacture because the need for mounting redundant sensors throughout the aircraft can be eliminated. For example, the need for wiring to communicatively couple the redundant sensors to the flight control computer is eliminated. Moreover, because these redundant sensors can also be powered using power already available at the flight control computer, the need for additional wiring between the redundant sensors and power supplies can also be eliminated. 
     Those of skill in the art would further appreciate that the various illustrative logical blocks/tasks/steps, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. Some of the embodiments and implementations are described above in terms of functional and/or logical block components (or modules) and various processing steps. However, it should be appreciated that such block components (or modules) may be realized by any number of hardware, software, and/or firmware components configured to perform the specified functions. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention. For example, an embodiment of a system or a component may employ various integrated circuit components, e.g., memory elements, digital signal processing elements, logic elements, look-up tables, or the like, which may carry out a variety of functions under the control of one or more microprocessors or other control devices. In addition, those skilled in the art will appreciate that embodiments described herein are merely exemplary implementations. 
     The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. 
     The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. 
     In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Numerical ordinals such as “first,” “second,” “third,” etc. simply denote different singles of a plurality and do not imply any order or sequence unless specifically defined by the claim language. The sequence of the text in any of the claims does not imply that process steps must be performed in a temporal or logical order according to such sequence unless it is specifically defined by the language of the claim. The process steps may be interchanged in any order without departing from the scope of the invention as long as such an interchange does not contradict the claim language and is not logically nonsensical. 
     Furthermore, depending on the context, words such as “connect” or “coupled to” used in describing a relationship between different elements do not imply that a direct physical connection must be made between these elements. For example, two elements may be connected to each other physically, electronically, logically, or in any other manner, through one or more additional elements. 
     While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. For example, although the disclosed embodiments are described with reference to a flight control computer of an aircraft, those skilled in the art will appreciate that the disclosed embodiments could be implemented in other types of computers that are used in other types of vehicles including, but not limited to, spacecraft, submarines, surface ships, automobiles, trains, motorcycles, etc. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.