Patent Description:
Aircraft are used to transport passengers and cargo between various locations. An aircraft such as an airplane includes numerous flight control surfaces, which are aerodynamic devices that are adjustable to control attitude of the airplane during flight. One type of flight control surface is an aileron, which is mounted on a trailing edge of a wing. Another type of flight control surface is an elevator, which is a moveable portion of a horizontal stabilizer. A rudder is a moveable portion on a trailing edge of a vertical stabilizer. A flap is mounted on a trailing edge of an inboard section of a wing. A slat is a leading edge device that is an extension of the front of a wing. <CIT> discloses a deployment mechanism for deploying a deployable member supported on tracks relative to a base member and comprising a brake system operable in response to relative skewing of the tracks. <CIT> discloses aircraft systems with shape memory alloy (SMA) actuators, and associated methods; one such system includes an airfoil, a deployable device coupled to the airfoil, and a shape memory alloy actuator coupled between the airfoil and the deployable device; an activatable link can be positioned between the actuator and the deployable device, and can have an engaged configuration in which motion of the actuator is transmitted to the deployable device, and a disengaged configuration in which motion of the actuator is not transmitted to the deployable device.

An unrestrained slat condition refers to a scenario when the slat is able to freely move to any position based on air load without being able to be arrested. An unrestrained slat condition can occur when an actuator uncouples from the slat.

Known slat actuation designs can be bulky, costly, and complex. For example, the known slat actuation designs can incorporate dual rotary actuators with internal, passively engaged no-back brakes that prevent unrestrained slat conditions.

A need exists for a system and a method that is configured to arrest unrestrained slat motion. Further, a need exists for a system and a method for effectively and efficiently arresting unrestrained slat motion, such as without the use of a secondary actuator or complex method of restraining free motion. Such systems and methods would provide significant cost, weight, and complexity savings over prior known systems and methods.

With those needs in mind, certain examples of the present disclosure provide a system including a flight control surface, an actuator configured to control motion of the flight control surface, and a brake configured to engage at least a portion of the flight control surface in response to the flight control surface disengaging from the actuator. For example, the brake is configured to engage at least a portion of a track of the flight control surface (that is, in at least one example, the flight control surface includes a track, such as an internal track). The brake arrests unrestrained motion of the flight control surface when the brake engages the at least a portion of the flight control surface.

In at least one example, the flight control surface is a slat of a wing, and the at least a portion is a track of the slat. In at least one example, the actuator is a linear hydraulic actuator.

In at least one example, the system also includes one or more sensors configured to detect a position of the flight control surface. The position of the flight control surface is used to determine whether the flight control surface is disengaged from the actuator.

In at least one example, the system also includes a control unit in communication with the brake. The control unit is configured to determine whether the flight control surface is disengaged from the actuator, and to control operation of the brake.

In at least one example, the brake is configured to engage the at least a portion of the flight control surface without the use of an additional actuator.

In at least one example, the brake includes a main housing disposed in relation to the at least a portion of the flight control surface. The main housing includes an internal chamber. One or more pistons are sealingly and moveably secured within one or more channels of the main housing. Hydraulic fluid is configured to pass into the internal chamber and force the one or more pistons into engagement with the at least a portion of the flight control surface. In at least one further example, the one or more pistons are tethered to the main housing by one or more springs within the internal chamber. In at least one example, the brake further includes a valve disposed on or within a fluid inlet to the internal chamber. In at least one further example, the fluid inlet is in fluid communication with a fluid delivery line in fluid communication with a fluid reservoir that retains the hydraulic fluid.

In at least one example, the one or more pistons include a first piston disposed to a first side of the at least a portion of the flight control surface, and a second piston disposed to a second side of the at least a portion of the flight control surface.

Certain examples of the present disclosure provide a method including controlling, by an actuator, motion of a flight control surface; engaging, by a brake, at least a portion of the flight control surface in response to the flight control surface disengaging from the actuator; and arresting, by said engaging, unrestrained motion of the flight control surface.

Examples of the present disclosure provide systems and methods including a slat track braking mechanism configured to arrest control surface movement in the event of an actuator disconnection.

<FIG> illustrates a schematic block diagram of a system <NUM> for controlling unrestrained motion of a flight control surface <NUM> of an aircraft <NUM>, according to an example of the present disclosure. The system <NUM> includes a brake <NUM> coupled to a portion of the flight control surface <NUM>, such as a track of the flight control surface <NUM> that drives motion of the flight control surface <NUM>. In at least one example, the flight control surface <NUM> is a slat, and the portion of the flight control surface <NUM> is a track of the slat. In at least one other example, the flight control surface <NUM> is an aileron. As another example, the flight control surface <NUM> is an elevator. As another example, the flight control surface <NUM> is a flap.

One or more sensors <NUM> are configured to detect a position of the flight control surface <NUM> (or a portion thereon). For example, the sensor(s) <NUM> can be an optical sensor, an ultrasonic sensor, a camera, an encoder, and/or the like that is configured to detect the position of one more portions of the flight control surface <NUM>.

An actuator <NUM> is coupled to a portion of the flight control surface <NUM> and a fixed portion of the aircraft <NUM>. For example, the actuator <NUM> can be secured to a fixed spar and a track of the flight control surface <NUM>. In at least one example, the actuator <NUM> is a linear hydraulic actuator. In at least one example, the actuator <NUM> is coupled to the flight control surface <NUM> through one or more gears. The actuator <NUM> is configured to operate to move the flight control surface <NUM> between different positions, such as an extended position and a retracted position.

A control unit <NUM> is in communication with the brake <NUM>, the sensor(s) <NUM> and the actuator <NUM>, such as through one or more wired or wireless connections. The control unit <NUM> is configured to operate the brake <NUM> in response to detection of an unrestrained flight control surface condition, such as an unrestrained slat condition.

In operation, the actuator <NUM> is configured to move the flight control surface <NUM> in response to commands from a control system of the aircraft <NUM>. The sensor(s) <NUM> detects the position of at least a portion of the flight control surface <NUM> and outputs position signals <NUM> indicative of the position to the control unit <NUM>. The control unit <NUM> analyzes the position of the at least a portion of the flight control surface <NUM> based on the position signals <NUM> received from the sensor(s) <NUM> in relation to operation of the actuator <NUM>. If the position of the one or more portions of the flight control surface <NUM> conforms to operation of the actuator <NUM> (for example, where the portion(s) should be in relation to the operation of the actuator <NUM>), the control unit <NUM> refrains from operating the brake <NUM>. If, however, the position of the one or more portions of the flight control surface <NUM> do not conform to the operation of the actuator <NUM>, the control unit <NUM> determines that the actuator <NUM> is uncoupled from the flight control surface, thereby indicating an unrestrained condition of the flight control surface <NUM>, and therefore operates the brake <NUM> to restrain motion of the flight control surface <NUM>.

As described herein, the system <NUM> includes the flight control surface <NUM>, the actuator <NUM> configured to control motion of the flight control surface <NUM>, and the brake <NUM> configured to engage at least a portion of the flight control surface <NUM> in response to the flight control surface <NUM> disengaging from the actuator <NUM>. The brake <NUM> arrests (for example, stops, prevents, minimizes, or otherwise reduces) unrestrained motion of the flight control surface <NUM> when the brake <NUM> engages the at least a portion of the flight control surface <NUM>.

In at least one example, the brake <NUM> is configured to engage the at least a portion of the flight control surface <NUM> without the use of an additional actuator, motor, or the like. That is, the brake <NUM> is not coupled to an additional engine, actuator, or motor. Instead, the brake <NUM> can be controlled by hydraulics, and under the control of the control unit <NUM>, as described herein. Because no additional actuators, engines, motors, or the like are used, the system <NUM> is lighter, less costly, and less complex than prior known systems.

As used herein, the term "control unit," "central processing unit," "CPU," "computer," or the like may include any processor-based or microprocessor-based system including systems using microcontrollers, reduced instruction set computers (RISC), application specific integrated circuits (ASICs), logic circuits, and any other circuit or processor including hardware, software, or a combination thereof capable of executing the functions described herein. Such are exemplary only, and are thus not intended to limit in any way the definition and/or meaning of such terms. For example, the control unit <NUM> may be or include one or more processors that are configured to control operation, as described herein.

The control unit <NUM> is configured to execute a set of instructions that are stored in one or more data storage units or elements (such as one or more memories), in order to process data. For example, the control unit <NUM> may include or be coupled to one or more memories. The data storage units may also store data or other information as desired or needed. The data storage units may be in the form of an information source or a physical memory element within a processing machine.

The set of instructions may include various commands that instruct the control unit <NUM> as a processing machine to perform specific operations such as the methods and processes of the various examples of the subject matter described herein. The set of instructions may be in the form of a software program. The software may be in various forms such as system software or application software. Further, the software may be in the form of a collection of separate programs, a program subset within a larger program, or a portion of a program. The software may also include modular programming in the form of object-oriented programming. The processing of input data by the processing machine may be in response to user commands, or in response to results of previous processing, or in response to a request made by another processing machine.

The diagrams of examples herein may illustrate one or more control or processing units, such as the control unit <NUM>. It is to be understood that the processing or control units may represent circuits, circuitry, or portions thereof that may be implemented as hardware with associated instructions (e.g., software stored on a tangible and (optionally, non-transitory) computer readable storage medium, such as a computer hard drive, ROM, RAM, or the like) that perform the operations described herein. The hardware may include state machine circuitry hardwired to perform the functions described herein. Optionally, the hardware may include electronic circuits that include and/or are connected to one or more logic-based devices, such as microprocessors, processors, controllers, or the like. Optionally, the control unit <NUM> may represent processing circuitry such as one or more of a field programmable gate array (FPGA), application specific integrated circuit (ASIC), microprocessor(s), and/or the like. The circuits in various examples may be configured to execute one or more algorithms to perform functions described herein. The one or more algorithms may include aspects of examples disclosed herein, whether or not expressly identified in a flowchart or a method.

<FIG> illustrates a perspective front view of the aircraft <NUM>, according to an example of the present disclosure. The aircraft <NUM> includes a propulsion system <NUM> that includes engines <NUM>, for example. Optionally, the propulsion system <NUM> may include more engines <NUM> than shown. The engines <NUM> are carried by wings <NUM> of the aircraft <NUM>. In other embodiments, the engines <NUM> may be carried by a fuselage <NUM> and/or an empennage <NUM>. The empennage <NUM> may also support horizontal stabilizers <NUM> and a vertical stabilizer <NUM>. Referring to <FIG>, the system <NUM> can be used to control various flight control surfaces <NUM>, such as slats and/or flaps of the wings <NUM>, elevators of the horizontal stabilizers, a rudder of the vertical stabilizer <NUM>, and/or the like. <FIG> shows an example of an aircraft <NUM>. It is to be understood that the aircraft <NUM> can be sized, shaped, and configured differently than shown in <FIG>.

<FIG> illustrates a top internal view of a portion of a wing <NUM> of the aircraft <NUM>, according to an example of the present disclosure. In at least one example, the wing <NUM> includes the system <NUM>, which includes brakes <NUM> coupled to tracks <NUM> of the flight control surface <NUM>. As shown in <FIG>, the flight control surface <NUM> is a slat at a forward edge of the wing <NUM>. The actuator <NUM> is a linear hydraulic actuator coupled to the tracks <NUM>, such as through one or more linkages. In at least one example, the actuator <NUM> is directly connected to the slat, which includes the tracks <NUM>. The actuator <NUM> is configured to push the slat out and pull the slat in, while the tracks <NUM> help guide the slat along a predetermined path. The linkages can include one or more gears. The sensors <NUM> are secured to fixed portions of the wing <NUM>. For example, the sensors <NUM> are secured to a front spar extending from a main body <NUM> of the wing <NUM>.

<FIG> illustrates a lateral internal view of the wing <NUM> through line <NUM>-<NUM> of <FIG>, according to an example of the present disclosure. As noted, in at least one example, the flight control surface <NUM> is a slat at a forward edge of the wing <NUM>. In this example, the flight control surface <NUM> includes an aerodynamic front edge <NUM> and the track <NUM> extending therefrom. Referring to <FIG>, the track <NUM> is coupled to the actuator <NUM>. The main body <NUM> of the wing <NUM> includes ribs <NUM> that rotatably retain rollers <NUM>. The ribs <NUM> can be secured to or otherwise extend from a front spar <NUM> of the main body <NUM>. The track <NUM> is moveably coupled to the rollers <NUM>. As the actuator <NUM> moves the track <NUM> of the flight control surface <NUM>, the track <NUM> moves in relation to the rollers <NUM> to selectively move the flight control surface <NUM> between extended and retracted positions.

Each brake <NUM> can be secured to the main body <NUM>, such as at positions along the ribs <NUM>, and configured to engage the track <NUM>. For example, the brake <NUM> can be mounted to the rib(s) <NUM> at positions A or B, for example.

<FIG> illustrates a cross-sectional view of the brake <NUM> disengaged from the track <NUM> through line <NUM>-<NUM> of <FIG>, according to an example of the present disclosure. In at least one example, the brake <NUM> includes a main housing <NUM> disposed around a portion of the track <NUM>. For example, the main housing <NUM> extends around an upper portion of the track <NUM>. Optionally, the main housing <NUM> extends around a lower portion of the track <NUM>. The main housing <NUM> can be a caliper housing, for example, The main housing <NUM> includes an internal chamber <NUM>. A valve <NUM> is disposed on or within a fluid inlet <NUM> to the internal chamber <NUM>. The valve <NUM> can be located at different positions than shown, such as upstream from the location that is shown. The fluid inlet <NUM> is in fluid communication with a fluid delivery line <NUM> in fluid communication with a fluid reservoir <NUM>. The fluid reservoir <NUM> retains hydraulic fluid, such as water, oil, or the like.

Pistons <NUM> are secured to the main housing <NUM> through springs <NUM> secured to interior surfaces within the internal chamber <NUM>. As shown, a first piston <NUM> is disposed to one side <NUM> of the track <NUM>, and a second piston <NUM> is disposed to an opposite side <NUM> of the track <NUM>. Each piston <NUM> is sealingly and moveably secured within a channel <NUM> of the main housing <NUM>. The sides <NUM> and <NUM> can include brake material <NUM>, such as a material that is configured to increase frictional engagement with the pistons <NUM>.

<FIG> illustrates a cross-sectional view of the brake <NUM> engaging the track <NUM> through line <NUM>-<NUM> of <FIG>, according to an example of the present disclosure. Referring to <FIG>, when the control unit <NUM> determines, via the position signals <NUM> output from the sensors <NUM>, that the position of the track <NUM> (as the portion of the flight control surface <NUM>, in this case the slat) conforms to operation of the actuator <NUM>, the control unit <NUM> refrains from operating the brake <NUM> to engage the track <NUM>, as shown in <FIG>. Conversely, if the control unit <NUM> determines that the position of the track <NUM> does not conform to the operation of the actuator <NUM>, the control unit <NUM> operates the brake <NUM> to engage the track <NUM>, to restrain motion of the track <NUM>. For example, as shown in <FIG>, in response to determining that the position of the track <NUM> does not conform to the operation of the actuator <NUM>, the control unit <NUM> operates the valve <NUM>, such as by opening the valve <NUM>, to allow hydraulic fluid <NUM> from the fluid reservoir <NUM> to pass into the internal chamber <NUM>. As the hydraulic fluid <NUM> passes into the internal chamber <NUM>, the pressure of the hydraulic fluid <NUM> forces the pistons <NUM> to move toward and onto the track <NUM>, which extends the springs <NUM>, and clamps onto the track <NUM>, thereby restraining motion of the track <NUM>. In this manner, the system <NUM> arrests unrestrained motion of the flight control surface <NUM>, such as the slat shown in <FIG>.

In at least one example, the brake <NUM> also includes a bypass fluid path that is configured to return the hydraulic fluid <NUM> back to the fluid reservoir <NUM> to disengage the brake <NUM> from the track <NUM>. One or more valves can be disposed within the bypass fluid path. The valve(s) can be controlled by the control unit <NUM>.

<FIG> illustrates a cross-sectional view of the brake <NUM> disengaged from the track <NUM> through line <NUM>-<NUM> of <FIG>, according to an example of the present disclosure. <FIG> illustrates a cross-sectional view of the brake <NUM> engaging the track <NUM> through line <NUM>-<NUM> of <FIG>, according to an example of the present disclosure. The brake <NUM> shown in <FIG> is similar to the brake <NUM> shown in <FIG>, except that the brake <NUM> in <FIG> can be disposed to only one side of the track <NUM>. In this example, the brake <NUM> can include a single piston <NUM> that is configured to engage one side of the track <NUM>.

Referring to <FIG>, the system <NUM> includes a brake <NUM> that is configured to engage and restrain at least a portion of the flight control surface <NUM> in response the flight control surface <NUM> disengaging from the actuator <NUM>. For example, the brake <NUM> is configured to engage and retain the track <NUM> of the flight control surface <NUM>, which can be a slat, to restrain motion thereof. In at least one example, the control unit <NUM> is configured to detect when the flight control surface <NUM> is disengaged from the actuator <NUM>, such as via the position signal(s) <NUM> received from the sensor(s) <NUM>. The system <NUM> is configured to prevent, minimize, or otherwise reduce unrestrained motion of the flight control surface <NUM> without the need for an additional actuator, which would otherwise add weight, complexity, and cost. Compared to prior known systems, the system <NUM> is less costly, lighter, and simpler, thereby easing integration into existing aircraft. The brakes <NUM> can be engaged at any point in the stroke of the track <NUM>, for example.

In at least one example, the brake <NUM> includes the main housing <NUM> disposed in relation to the at least a portion of the flight control surface <NUM>. For example, the main housing <NUM> can be in close proximity (such as within <NUM> feet or less), and secured around a portion of the flight control surface <NUM>. As an example, the main housing <NUM> is disposed over or under a portion of the track <NUM> of a slat. The main housing includes the internal chamber <NUM>. One or more pistons <NUM> are sealingly and moveably secured within one or more channels <NUM> of the main housing <NUM>. Hydraulic fluid is configured to pass into the internal chamber <NUM> and force the one or more pistons <NUM> into engagement with the at least a portion (such as a track) of the flight control surface <NUM>. In at least one example, the one or more pistons <NUM> are tethered to the main housing by one or more springs <NUM> within the internal chamber <NUM>. In at least one example, the brake <NUM> also includes the valve <NUM> disposed on or within the fluid inlet <NUM> to the internal chamber <NUM>. The fluid inlet <NUM> is in fluid communication with the fluid delivery line <NUM>, which is in fluid communication with the fluid reservoir <NUM> that retains the hydraulic fluid. In at least one example, a first piston <NUM> is disposed to a first side of the at least a portion (such as a track) of the flight control surface <NUM>, and a second piston <NUM> is disposed to a second side of the at least a portion (such as the track) of the flight control surface <NUM>.

<FIG> illustrates a flow chart of a method for controlling unrestrained motion of a flight control surface of an aircraft, according to an example of the present disclosure. Referring to <FIG> and <FIG>, at <NUM>, the actuator <NUM> is operated to selectively move the flight control surface <NUM> between desired positions. At <NUM>, it is determined if the actuator <NUM> is uncoupled from the flight control surface <NUM>. For example, the control unit <NUM> determines whether or not the actuator <NUM> is uncoupled from the flight control surface <NUM> through the position signals <NUM> received from the sensor(s) <NUM>. If the actuator <NUM> is not uncoupled from the flight control surface <NUM>, the method proceeds to <NUM>, at which the control unit <NUM> refrains from engaging the flight control surface <NUM> with the brake <NUM>. The method then returns to <NUM>.

If, however, it is determined that the actuator <NUM> is uncoupled from the flight control surface <NUM> at <NUM>, the method proceeds to <NUM>, at which the flight control surface <NUM> is engaged with the brake <NUM>, thereby restraining motion of the flight control surface <NUM>. In this manner, the brake <NUM> is controlled to prevent, minimize, or otherwise reduce unrestrained motion of the flight control surface <NUM>.

As described herein, examples of the present disclosure provide systems and methods configured to arrest unrestrained flight control surface motion. The systems and methods effectively and efficiently arrest unrestrained flight control surface motion, such as without the use of a secondary actuator or complex method of restraining free motion. As described herein, examples of the present disclosure provide such systems and methods having significant cost, weight, and complexity savings over prior known systems and methods.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described examples (and/or aspects thereof) can be used in combination with each other. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the various examples of the disclosure without departing from their scope. While the dimensions and types of materials described herein are intended to define the parameters of the various examples of the disclosure, the examples are by no means limiting and are exemplary examples. Many other examples will be apparent to those of skill in the art upon reviewing the above description. The scope of the various examples of the disclosure should, therefore, be determined with reference to the appended claims.

In the appended claims and the detailed description herein, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein. " Moreover, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

Claim 1:
A system (<NUM>) comprising:
a flight control surface (<NUM>);
an actuator (<NUM>) configured to control motion of the flight control surface (<NUM>); and
a brake (<NUM>) configured to engage at least a portion of the flight control surface (<NUM>) in response to the flight control surface (<NUM>) disengaging from the actuator (<NUM>),
wherein the brake (<NUM>) is configured to arrest unrestrained motion of the flight control surface (<NUM>) when the brake (<NUM>) engages the at least a portion of the flight control surface (<NUM>).