Patent Application
20130043354
Embodiments of the present disclosure relate generally to fluid-dynamic design. More particularly, embodiments of the present disclosure relate to design of fluid-dynamic control surfaces.
In aeronautics and aeronautical engineering, camber comprises an asymmetry between an upper surface and a lower surface of an airfoil. A camber of an airfoil can be defined by a camber line, which is the curve that is halfway between the upper surface and the lower surface of the airfoil. Camber is generally an important contributing factor determining a stall speed of an aircraft. A change in a camber of an airfoil can change a stall speed of an aircraft.
A system and methods for configuring a fluid-dynamic body is disclosed. A fluid-dynamic body is shaped into a first camber configuration, and the fluid-dynamic body is shaped into a second camber configuration using a shape memory alloy actuator.
In an embodiment, a method for configuring a fluid-dynamic body configures a camber of a fluid-dynamic body by activating a shape memory alloy actuator coupled to the fluid-dynamic body.
In another embodiment, a variable camber fluid-dynamic body system comprises a fluid-dynamic body and a shape memory alloy actuator. The fluid-dynamic body is operable to assume a first camber configuration and a second camber configuration. The shape memory alloy actuator is operable to configure the fluid-dynamic body into the first camber configuration in response to a first control temperature. The shape memory alloy actuator is further operable to configure the fluid-dynamic body into the second camber configuration in response to a second control temperature.
In yet another embodiment, a method for providing a variable camber fluid-dynamic body system provides a fluid-dynamic body operable to assume a first camber configuration and a second camber configuration, and couples a shape memory alloy actuator to the fluid-dynamic body. The shape memory alloy actuator is operable to configure the fluid-dynamic body into the first camber configuration in response to a first control temperature, and configure the fluid-dynamic body into the second camber configuration in response to a second control temperature.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
A more complete understanding of embodiments of the present disclosure may be derived by referring to the detailed description and claims when considered in conjunction with the following figures, wherein like reference numbers refer to similar elements throughout the figures. The figures are provided to facilitate understanding of the disclosure without limiting the breadth, scope, scale, or applicability of the disclosure. The drawings are not necessarily made to scale.
The following detailed description is exemplary in nature and is not intended to limit the disclosure or the application and uses of the embodiments of the disclosure. Descriptions of specific devices, techniques, and applications are provided only as examples. Modifications to the examples described herein will be readily apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other examples and applications without departing from the spirit and scope of the disclosure. The present disclosure should be accorded scope consistent with the claims, and not limited to the examples described and shown herein.
Embodiments of the disclosure may be described herein in terms of functional and/or logical block components and various processing steps. It should be appreciated that such block components may be realized by any number of hardware, software, and/or firmware components configured to perform the specified functions. For the sake of brevity, conventional techniques and components related to aerodynamics, shape memory alloys, vehicle structures, fluid dynamics, flight control systems, and other functional aspects of systems described herein (and the individual operating components of the systems) may not be described in detail herein. In addition, those skilled in the art will appreciate that embodiments of the present disclosure may be practiced in conjunction with a variety of hardware and software, and that the embodiments described herein are merely example embodiments of the disclosure.
Embodiments of the disclosure are described herein in the context of a practical non-limiting application, namely, an aircraft airfoil. Embodiments of the disclosure, however, are not limited to such aircraft airfoil applications, and the techniques described herein may also be utilized in other applications. For example but without limitation, embodiments may be applicable to hydrofoils, wind turbines, tidal power turbines, and the like.
As would be apparent to one of ordinary skill in the art after reading this description, the following are examples and embodiments of the disclosure and are not limited to operating in accordance with these examples. Other embodiments may be utilized and structural changes may be made without departing from the scope of the exemplary embodiments of the present disclosure.
Referring more particularly to the drawings, embodiments of the disclosure may be described in the context of an exemplary aircraft manufacturing and service method 100 (method 100) as shown in
Each of the processes of method 100 may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may comprise, for example but without limitation, any number of aircraft manufacturers and major-system subcontractors; a third party may comprise, for example but without limitation, any number of vendors, subcontractors, and suppliers; and an operator may comprise, for example but without limitation, an airline, leasing company, military entity, service organization; and the like.
As shown in
Apparatus and methods embodied herein may be employed during any one or more of the stages of the method 100. For example, components or subassemblies corresponding to production of the process 108 may be fabricated or manufactured in a manner similar to components or subassemblies produced while the aircraft 200 is in service. In addition, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized during production stages of the process 108 and the system integration 110, for example, by substantially expediting assembly of or reducing the cost of an aircraft 200. Similarly, one or more of apparatus embodiments, method embodiments, or a combination thereof may be utilized while the aircraft 200 is in service, for example and without limitation, to maintenance and service 116.
A shape memory alloy (SMA) remembers its original shape after being deformed from that original shape. An SMA returns to its original shape when it is heated (shape memory effect) or when the deforming pressure is removed (superelasticity). An SMA that returns to its original shape when heated is a one-way SMA. A two-way SMA remembers two different shapes: one shape at a relative low temperature, and another shape at a relative high temperature. Setting the two shapes by thermo-mechanical processing is known as “training” the SMA. An SMA with the two shapes set is known as a “trained” SMA. The shape properties of a trained SMA result from a temperature initiated martensitic phase transformation from a low symmetry (martensite) to a highly symmetric (austenite) crystal structure.
The temperatures at which the SMA changes its structure depend on a particular alloy, and can be tuned by varying a chemical mix and thermo-mechanical processing. Some common SMA materials may comprise, for example but without limitation, copper-zinc-aluminum, copper-aluminum-nickel, nickel-titanium-platinum, nickel-titanium-palladium, nickel-titanium-hafnium, nickel-titanium (NiTi or Nitinol), and the like. NiTi SMA alloys generally have superior mechanical properties to copper-based SMAs, but are also generally more expensive. The SMA actuators according to various embodiments of the disclosure may be made, for example but without limitation, from any of these aforementioned SMA materials.
The airfoil 302 comprises a variable camber and as such is also referred to as the variable camber airfoil 302. The variable camber airfoil 302 is operable to configure a shape of a camber 414 (
The variable camber airfoil 302/400 may comprise a cross section of a lifting surface and/or a cross section of a control surface of a fluid-dynamic body. The control surface may comprise, for example but without limitation, a slat, an aileron, a tail, a rudder, an elevator, a flap, a spoiler, an elevon, and the like. The lift surface may comprise, for example but without limitation, a wing, a canard, a horizontal stabilizer, and the like.
The SMA actuator 304 is operable to vary a shape (i.e., bend, deflect, change shape) of a camber in response to heating and/or cooling. In this manner, the camber 414 can change shape to alter a flow over the variable camber airfoil 302/400. In one embodiment, the SMA actuator 304 is controlled via a passive control mechanism to control the shape of the camber 414 based on an ambient temperature corresponding to an altitude at a flight condition. In another embodiment, the controller 308 may include or be realized as a controller (connected to the aircraft systems), to facilitate controlling a deformation (i.e., changing the shape) of the camber 414 as explained in more detail below.
The SMA actuator 304 according to various embodiments of the disclosure may be made, for example but without limitation, from any of the SMA materials mentioned above. According to the various embodiments, the SMA actuator 304 comprises an SMA hinge 502/504/506/602/604 (
Various coupling means 306 may comprise any coupling technology suitable for use by the system 300. The various coupling means 306 may comprise, for example but without limitation, gluing, welding, and the like.
The controller 308 may comprise, for example but without limitation, a processor module 310, a memory module 312, and the like. The controller 308 may be implemented as, for example but without limitation, a part of an aircraft system, a centralized aircraft processor, a subsystem computing module devoted to the variable camber airfoil 302, and the like.
The controller 308 is configured to thermally control the SMA actuator 304 to vary a shape of the camber 414 according to various operation conditions. The operation conditions may comprise, for example but without limitation, flight conditions, ground operations, and the like. The flight conditions may comprise, for example but without limitation, take off, cruise, approach, landing, and the like. The ground operations may comprise, for example but without limitation, air breaking after landing, and the like. The controller 308, may be located remotely from the SMA actuator 304, or may be coupled to the SMA actuator 304. The SMA actuator 304 is controllable by adjusting a temperature between martensite and austenite finish temperatures such that shapes in between the extreme actuated states can be selected and maintained using the controller 308.
In operation, the controller 308 may control the SMA actuator 304 by monitoring the temperature of the SMA actuators 304 and by heating and/or cooling at least a portion of the SMA actuator 304 as needed. The heating/cooling of the SMA actuator 304 may be provided by, for example but without limitation, the aircraft cooling/heating systems and the like. For example, a heater may utilize an electrical heater element and a controllable current source where a temperature is proportional to a current applied to the heater element. In this manner, the controller 308 determines a temperature based on a current flight condition, and provides heating/cooling to activate/deactivate the SMA actuator 304. This enables the controller 308 to vary the shape of the camber 414 in accordance with current flight conditions, e.g., whether an aircraft is approaching, landing, taking off or in cruise. The controller 308 may be used to optimize a shape of the camber 414 for noise, lift, drag, and the like.
In one embodiment, the controller 308 is configured to change temperature of the SMA actuators 304 non-uniformly. The controller 308 may vary temperatures of respective segments of the SMA actuator 304 separately from each other, wherein each of the temperatures is different from one another. In this manner, different regions of the SMA actuator 304 can be heated to different temperatures via the controller 308 to effect different levels of change in shape of the camber 414 in different regions of the variable camber airfoil 302. For example, different SMA actuators can be heated by different amounts to maintain a desired shape.
The processor module 310 comprises processing logic that is configured to carry out the functions, techniques, and processing tasks associated with the operation of the system 300. In particular, the processing logic is configured to support the system 300 described herein. For example, the processor module 310 may direct the SMA actuator 304 to vary a shape of the camber 414 based on various flight conditions.
The processor module 310 may be implemented, or realized, with a general purpose processor, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In this manner, a processor may be realized as a microprocessor, a controller, a microcontroller, a state machine, or the like. A processor may also be implemented as a combination of computing devices, e.g., a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a digital signal processor core, or any other such configuration.
The memory module 312 may comprise a data storage area with memory formatted to support the operation of the system 300. The memory module 312 is configured to store, maintain, and provide data as needed to support the functionality of the system 300. For example, the memory module 312 may store flight configuration data, control temperature data, and the like.
In practical embodiments, the memory module 312 may comprise, for example but without limitation, a non-volatile storage device (non-volatile semiconductor memory, hard disk device, optical disk device, and the like), a random access storage device (for example, SRAM, DRAM), or any other form of storage medium known in the art.
The memory module 312 may be coupled to the processor module 310 and configured to store, for example but without limitation, a database, and the like. Additionally, the memory module 312 may represent a dynamically updating database containing a table for updating the database, and the like. The memory module 312 may also store, a computer program that is executed by the processor module 310, an operating system, an application program, tentative data used in executing a program, and the like.
The memory module 312 may be coupled to the processor module 310 such that the processor module 310 can read information from and write information to the memory module 312. For example, the processor module 310 may access the memory module 312 to access an aircraft speed, a flight control surface position, an angle of attack, a Mach number, an altitude, and the like.
As an example, the processor module 310 and memory module 312 may reside in respective application specific integrated circuits (ASICs). The memory module 312 may also be integrated into the processor module 310. In an embodiment, the memory module 312 may comprise a cache memory for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor module 310.
The variable camber airfoil 400 may be characterized by the mean camber line 410 (camber line) and a chord line 412. The camber line 410 may comprise a curve halfway between the upper surface 420 and the lower upper surface 422 of the variable camber airfoil 400 characterizing an asymmetry between the upper surface 420 and the lower surface 422. The camber 414 of the variable camber airfoil 400 can be defined by a camber line 410. The camber 414 may comprise distances between the camber line 410 and the chord line 412 defining a shape of the camber line 410.
The first SMA hinge 502 is coupled to the first aerodynamic structure 518, and the second SMA hinge 504 is coupled to the first aerodynamic structure 518 and the second aerodynamic structure 520. The third SMA hinge 506 is coupled to the second aerodynamic structure 520 and the third aerodynamic structure 522. The first SMA hinge 502, the second SMA hinge 504, and the third SMA hinge 506 are each operable to activate (e.g., twist) in response to a first SMA activation control temperature, a second SMA activation control temperature, and a third SMA activation control temperature respectively. The first SMA hinge 502, the second SMA hinge 504, and the third SMA hinge 506 may be controlled individually or in combination. The first SMA activation control temperature, the second SMA activation control temperature, and the third SMA activation control temperature may be controlled individually (e.g., at separate individual temperatures) or in combination (e.g., two or more may have a temperature in common).
The variable camber structure 500 is operable to change a shape of the camber 414 (
The first SMA hinge 602 is coupled to the first aerodynamic structure 606, and the second SMA hinge 604 is coupled to the first aerodynamic structure 606 and the second aerodynamic structure 608. The first SMA hinge 602 may also be coupled to the fluid-dynamic body 302. The first SMA hinge 602 and the second SMA hinge 604 are each operable to activate (e.g., twist) in response to a first SMA activation control temperature and a second SMA activation control temperature respectively. The first SMA hinge 602 and the second SMA hinge 604 may be controlled individually or in combination. The first SMA activation control temperature and the second SMA activation control temperature may be controlled individually (e.g., at separate individual temperatures) or in combination (e.g., two or more may have a temperature in common).
The variable camber structure 600 is operable to change a shape of the camber 414 (
In the embodiments shown in
The lifting surface assembly 900 comprises the upper surface 420 (removed in
Using the truss SMA actuator 902, the variable camber airfoil 302/400 (
For illustrative purposes, the following description of process 1100 may refer to elements mentioned above in connection with
Process 1100 may begin by configuring a camber such as the camber 414 of a fluid-dynamic body such as the fluid-dynamic body 302 by activating a shape memory alloy actuator such as the SMA actuator 304 coupled with the fluid-dynamic body 302 (task 1102).
Process 1100 may continue by configuring the fluid-dynamic body 302 into a first camber configuration such as the first camber configuration 406 (task 1104).
Process 1100 may continue by configuring the fluid-dynamic body 302 into a second camber configuration such as the second camber configuration 408 using the SMA actuator 304 (task 1106).
Process 1100 may continue by bending the fluid-dynamic body 302 using a shape memory alloy truss structure such as the truss SMA actuator 902 coupled to the fluid-dynamic body 302 (task 1108).
For illustrative purposes, the following description of process 1200 may refer to elements mentioned above in connection with
Process 1200 may begin by providing a fluid-dynamic body such as the fluid-dynamic body 302 operable to assume a first camber configuration such as the first camber configuration 406 and a second camber configuration such as the second camber configuration 408 (task 1202). The fluid-dynamic body 302 may comprise, for example but without limitation, an airfoil, a wing, a fuselage, a strut, a winglet, an elevator, a rudder, an aileron, an elevon, and the like.
Process 1200 may continue by coupling a shape memory alloy actuator such as the SMA actuator 304 to the fluid-dynamic body 302 (task 1204). The shape memory alloy actuator is operable to configure the fluid-dynamic body 302 into the first camber configuration 406 in response to a first control temperature, and configure the fluid-dynamic body 302 into the second camber configuration 408 in response to a second control temperature. The SMA actuator 304 may comprise, the SMA hinge 502/504/506/602/604 (
Process 1200 may continue by coupling the SMA actuator 304 to a first aerodynamic structure such as the first aerodynamic structure 606 and a second aerodynamic structure such as the second aerodynamic structure 608 (task 1206).
Process 1200 may continue by bonding the SMA actuator 304 between a first composite laminate layer such as the first composite laminate layer 712 and a second composite laminate layer such as the second composite laminate layer 714 (task 1208).
In this manner, the embodiments of the disclosure provide various means for configuring a camber of a fluid-dynamic body using SMA actuators.
In this document, the terms “computer program product”, “computer-readable medium”, “computer readable storage medium”, and the like may be used generally to refer to media such as, for example, memory, storage devices, or storage unit. These and other forms of computer-readable media may be involved in storing one or more instructions for use by the processor module 310 to cause the processor module 310 to perform specified operations. Such instructions, generally referred to as “computer program code” or “program code” (which may be grouped in the form of computer programs or other groupings), when executed, enable power utilization scheduling methods of the system 700.
The above description refers to elements or nodes or features being “connected” or “coupled” together. As used herein, unless expressly stated otherwise, “connected” means that one element/node/feature is directly joined to (or directly communicates with) another element/node/feature, and not necessarily mechanically. Likewise, unless expressly stated otherwise, “coupled” means that one element/node/feature is directly or indirectly joined to (or directly or indirectly communicates with) another element/node/feature, and not necessarily mechanically. Thus, although
Terms and phrases used in this document, and variations thereof, unless otherwise expressly stated, should be construed as open ended as opposed to limiting. As examples of the foregoing: the term “including” should be read as mean “including, without limitation” or the like; the term “example” is used to provide exemplary instances of the item in discussion, not an exhaustive or limiting list thereof; and adjectives such as “conventional,” “traditional,” “normal,” “standard,” “known” and terms of similar meaning should not be construed as limiting the item described to a given time period or to an item available as of a given time, but instead should be read to encompass conventional, traditional, normal, or standard technologies that may be available or known now or at any time in the future.
Likewise, a group of items linked with the conjunction “and” should not be read as requiring that each and every one of those items be present in the grouping, but rather should be read as “and/or” unless expressly stated otherwise. Similarly, a group of items linked with the conjunction “or” should not be read as requiring mutual exclusivity among that group, but rather should also be read as “and/or” unless expressly stated otherwise. Furthermore, although items, elements or components of the disclosure may be described or claimed in the singular, the plural is contemplated to be within the scope thereof unless limitation to the singular is explicitly stated. The presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases may be absent.
As used herein, unless expressly stated otherwise, “operable” means able to be used, fit or ready for use or service, usable for a specific purpose, and capable of performing a recited or desired function described herein. In relation to systems and devices, the term “operable” means the system and/or the device is fully functional and calibrated, comprises elements for, and meets applicable operability requirements to perform a recited function when activated. In relation to systems and circuits, the term “operable” means the system and/or the circuit is fully functional and calibrated, comprises logic for, and meets applicable operability requirements to perform a recited function when activated.
