Abstract:
A flap actuation system for an aircraft can include a first flap panel connected with a first in-board actuator and a first out-board actuator. A first electronic control unit (ECU) can be electrically coupled to and configured to control the first in-board actuator, and a second ECU can be electrically coupled to and configured to control the first out-board actuator. The flap system may further include a second flap panel connected with a second in-board actuator and a second out-board actuator. A third ECU can be electrically coupled to and configured to control the second in-board actuator, and a fourth ECU can be electrically coupled to and configured to control the second out-board actuator.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a national stage filing based upon International Application No. PCT/US2013/031011, with an international filing date of Mar. 13, 2013, which claims the benefit of U.S. Provisional Application No. 61/734,232, filed Dec. 6, 2012, the disclosures of which are incorporated herein by reference in their entirety. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates generally to aircraft flap systems, including electronically-synchronized flap systems for fixed-wing aircraft. 
         [0004]    2. Description of the Related Art 
         [0005]    One known type of fixed-wing aircraft flap system is a fully distributed fly-by-wire flap system. In such a system, each flap actuator—for example, an in-board actuator and an out-board actuator for the left wing, and an in-board actuator and an out-board actuator for the right wing—may be independently positioned and actuated, without any interconnection. As a result, the positions of the actuators, and thus of the flap panels, may be difficult to consistently synchronize. 
         [0006]    One conventional solution for synchronizing the positions of flap actuators is embodied in the system  10  shown in  FIG. 1 . The conventional system  10  relies, generally, on mechanical synchronization of the flap panel actuators. The conventional system  10  can include a flap panel position input  12  using a data and signal communications path  14  to communicate with a flap electronic control unit (ECU)  16 , a motor/brake  18 , and a power distribution unit (PDU)  20 . In the left wing  22   L , the conventional system  10  can include a left flap panel  24   L , a left in-board actuator  26   LI , a left out-board actuator  26   LO , and a number of flap position sensors  28 . The right wing  22   R  similarly can include a right flap panel  24   R , a right in-board actuator  26   RI , a right out-board actuator  26   RO , and a number of flap position sensors  28 . For visual clarity, not all position sensors  28  are designated. 
         [0007]    In the conventional system  10 , the common motor/brake  18  can provide power for actuators  26   LI ,  26   LO ,  26   RI ,  26   RO  in the left wing  22   L  and right wing  22   R , which can be distributed by the PDU  20  to the respective actuators. To distribute power, a mechanical transmission system, such as a series of rotatable flexible torque shafts or torque tubes  30 , couples the PDU  20  to the in-board actuators  26   LI ,  26   RI  in each wing. Another mechanical transmission, such as flexible shafts or torque tubes  32 , couple each in-board actuator  26   LI ,  26   RI  with a respective out-board actuator  26   LO ,  26   RO . Thus, a single motor/brake  18  and single PDU  20  drive both flap panels  24   L ,  24   R  through mechanical transmissions  30 ,  32 . 
         [0008]    Because a single motor/brake  18  and a single PDU  20  are used to provide power to a plurality of flap actuators in both wings, these components along with the mechanical transmissions  30 ,  32  can be relatively large and heavy. Furthermore, the centrally located motor/brake  18  and PDU  20  can be relatively inefficient. As a result, these conventional systems may often be comparatively heavier and less efficient. 
       SUMMARY 
       [0009]    In an embodiment, a flap actuation system for an aircraft may include a first flap panel connected with a first in-board actuator and a first out-board actuator. A first electronic control unit (ECU) can be electrically coupled to and configured to control the first in-board actuator, and a second ECU can be electrically coupled to and configured to control the first out-board actuator. The flap system may further include a second flap panel connected with a second in-board actuator and a second out-board actuator. A third ECU can be electrically coupled to and configured to control the second in-board actuator, and a fourth ECU can be electrically coupled to and configured to control the second out-board actuator. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein: 
           [0011]      FIG. 1  generally illustrates a schematic of a conventional flap actuation system. 
           [0012]      FIG. 2  generally illustrates a schematic of an electronic flap actuation system in accordance with an embodiment of the present disclosure. 
           [0013]      FIG. 3  generally illustrates a schematic of an electronic flap panel actuator assembly that may be used in the electronic flap actuation system of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Reference will now be made in detail to embodiments of the present invention, examples of which are described herein and illustrated in the accompanying drawings. While the invention will be described in conjunction with embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. 
         [0015]    An embodiment of an electronic flap actuation system  110  is generally illustrated in  FIG. 2 , and an embodiment of an electronic flap panel actuator assembly  134  is shown in greater detail in  FIG. 3 . The system  110  can include a flap panel position input  112  using a data and signal communications path  114  to communicate with a plurality of electronic flap actuator assemblies  134 . The left wing  122   L  can include an inboard flap panel  124   LI  mechanically coupled with inboard flap panel actuator assemblies  134   LI1 ,  134   LI2 , an outboard flap panel  124   LO  mechanically coupled with outboard flap panel actuator assemblies  134   LO1 ,  134   LO2 , and a plurality of flap position sensors  128 . The right wing  122   R  similarly can include an inboard flap panel  124   RI  mechanically coupled with inboard flap panel actuator assemblies  134   RI1 ,  134   RI2 , an outboard flap panel  124   RO  mechanically coupled with outboard flap panel actuator assemblies  134   RO1 ,  134   RO2 , and a plurality of position sensors  128  for sensing a position of the respective flap panels. For visual clarity, not all flap position sensors  128  are designated. Furthermore, it should be understood that although multiple flap panels are illustrated for each wing, the synchronized flap systems described herein can also apply to an aircraft with a single flap panel in each wing. 
         [0016]    The flap panel actuator assemblies  134   LI1 ,  134   LI2 ,  134   LO1 ,  134   LO2 ,  134   RI1 ,  134   RI2 ,  134   RO1 ,  134   RO2  may be collectively referred to herein as the flap panel actuator assemblies  134 . A single one of the flap panel actuator assemblies  134  may be referred to as a flap panel actuator assembly  134 . Similarly, the flap panels  124   LO ,  124   LO ,  124   RI ,  124   RO  may be collectively referred to as the flap panels  124 , or individually as a flap panel  124 . Descriptions of a single flap panel actuator assembly  134  or a single flap panel  124  should be understood to apply equally to each flap panel actuator assembly  134  or to each flap panel  124 . 
         [0017]    The flap panel position input  112  may, for example, comprise an apparatus known in the art for commanding the position of one or more flap panels. In an embodiment, the flap panel position input  12  can be, for example, a flight control computer or a flap handle. The flap panel position input  12  can output or transmit flap panel commands over the data and signal communications path  114 . In an embodiment, the data and signal communications path  114  may operate according to ARINC 825 (i.e., Aeronautical Radio Incorporated) or any other appropriate communications protocol. 
         [0018]    As is generally shown in  FIG. 3 , an embodiment of a flap panel actuator assembly  134  may include an electronic control unit (ECU)  116 , a flap actuator (FLA)  126 , and a motor/brake (MTR/BRK)  118 . As is more clearly shown in  FIG. 2 , the ECU  116  can be configured to receive commands from a user/pilot, for example, through the flap panel position input  112 , and transmit or translate those commands into a position or movement of a respective one of the flap panels  124 . The provision of an ECU  116  for each flap actuator  126  allows the flap actuators  126  to be electronically synchronized, rather than mechanically synchronized as described above in a conventional actuation system. To convert commands into movement of a flap panel  124 , the ECU  116  can include hardware and/or software-based control (e.g., in the form of algorithms or code) for transmitting or translating user/pilot commands into flap panel control. Further, the plurality of ECUs  116  may be able to communicate with one another or with a main control unit over the data and signal communications path  114 . In an embodiment, the ECU  116  and other components in the system  110  can receive power from a  28  volt DC power source for generating control and communication signals, although any suitable power source can be provided. 
         [0019]    The operation of the electronic flap actuation system  10  will now be described. To move a flap panel  124 , an ECU  116  can issue commands to a motor/brake  118  with which it is coupled. The motor/brake  118  may, in turn, effect movement of (or slow or stop movement of) a respective flap actuator  126 . Because each actuator  126  may be coupled with one of the flap panels  124 , movement of an actuator  126  may result in a corresponding movement of the respective flap panel  124 . For example, the ECU  116  can be configured to control the motor/brake  118  with a set or prescribed velocity and a direction (e.g., extend or retract) to extend or retract the respective flap panel  124 . In an embodiment, each motor/brake  118  may receive power from a  115  volt AC power source, although any suitable power source can be provided. 
         [0020]    Each motor/brake  118  can include a motor configured to provide power to a flap actuator  126  for moving a respective one of the flap panels  124  and a brake for preventing such movement (i.e., for slowing the movement of or locking the position of the flap panel). It should be understood that the motor and brake portions of each motor/brake  118  may be physically separate components, although they are shown as a unitary assembly. In embodiments, each motor/brake  118  may comprise various acceptable devices or apparatus known in the art that are suitable for such an application. 
         [0021]    Proper in-flight operation may require that the flap panels  124  move in a form of synchronization. For this and other reasons, one or more position sensors  128  can be connected to the flap panels  124  and can be configured to sense and/or measure the positions of the flap panels  124 . Each ECU  116  can be operatively (e.g., electrically) coupled with the positions sensors  128  for monitoring the position of one or more portions of the flap panels  124 . Such a coupling may be indirect, such as through the flap position input  112 , for example, or may be direct to each ECU  116 . Using position data or measurements provided by the position sensors  128 , each ECU  116  can, for example, be configured to determine a configuration or asymmetry of the flap actuator  126  to which it is coupled relative to the other flap actuators  126 . In turn, each ECU  116  can determine a configuration or asymmetry between different panels  124  as well as skew of a single flap panel  124 . Each ECU  116  can also monitor one or more flap panels  124  for uncommanded/unintentional movement, or for failure to move when commanded, by using feedback from one or more position sensors  128 . In an embodiment, position sensors  128  can be, for example and without limitation, various position sensors known in the field for similar applications. Multiple different types of position sensors  128  may be used in a single aircraft or wing or, alternatively, all position sensors  128  may be of the same type. 
         [0022]    An ECU  116  can compare, for example and without limitation, various parameters including but not limited to skew, asymmetry, uncommanded/unintentional movement, and/or failed commanded movement to predetermined thresholds associated with failure states of the flap panels  124 . The system  110  may be configured so that in the event that readings from one or more position sensors  128  indicate that a failure state has occurred—i.e., that asymmetry, skew, uncommanded/unintentional movement, and/or failed commanded movement is approaching or is beyond a threshold—one or more ECUs  116  can, for example, command the brakes (e.g., via one or more motor/brakes  118 ) to shut down (i.e., lock) a flap panel  124  to help ensure safety and reliability. In an embodiment, one or more ECUs  116  may be configured to signal or command one or more motor/brakes  118  to correct for some amount of asymmetry or skew. 
         [0023]    Electronically-synchronized flap systems  110  such as generally disclosed herein can provide a number of advantages with respect to conventional flap systems. Because each flap actuator  126  can be coupled with its own motor/brake  118  and ECU  116 , the need for a large and inefficient centralized PDU, interconnection gear boxes, centralized torque transmission tubes/flex shafts and related support bearings associated with some conventional systems can be reduced or eliminated. As a result, the system  110  can have much lower weight and higher efficiency than a conventional system and may be simpler to install and maintain. In addition, the presence of an independent motor/brake for each flap actuator  126  can allow for the correction of minor skew across one or more flap panels  124  and asymmetry between the positions of one or more of the flap panels  124 . 
         [0024]    Electronically-synchronized flap systems  110  such as generally disclosed herein can also provide advantages with regards to reliability, installation, and maintenance. For example, critical features such as motor/brake controls and/or position determinations by an ECU  116  are multiplied and redundantly represented in the flap system  110  (e.g., through the use of multiple ECUs  116 ), thereby increasing the availability of the flap system  110  in the event of device malfunction. Furthermore, because each flap actuator  126  may be mechanically independent of the other flap actuators  126  and may be electronically-controlled independent of the other flap actuators  126 , rigging of the flap system  110  (i.e., alignment of the actuators  126  and the flap panels  124  during installation and maintenance) may be simplified. In an embodiment, the system  110  (i.e., each ECU  116 ) may be configured to automatically rig the actuators  126  and flap panels  124 . Such automatic rigging may save significant amounts of time and labor for installation and maintenance, thereby reducing the up-front and maintenance costs of the system  110  when compared to conventional systems. 
         [0025]    The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and various modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to explain the principles of the invention and its practical application, to thereby enable others skilled in the art to utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.