Patent Description:
An air vehicle such as a fixed-wing plane includes control surfaces coupled to a wing of the air vehicle that are selectively actuated to affect behavior of the air vehicle during takeoff, flight, and/or landing. For instance, a flap can be extended during takeoff or landing to increase lift of the wing and retracted to reduce drag when, for example, the air vehicle reaches a cruising altitude. Control surfaces such as flaps are coupled to the wing via support structures.

<CIT>, in accordance with its abstract, states: an actuator which comprises a cylinder, a piston arranged in the cylinder and adapted to be moved with the supply/discharge of operating oil to/from the cylinder, the movable rod connected to the piston, a screw shaft at least part of which is inserted into the movable rod, a nut threaded to the screw shaft so as to be movable integrally with the piston, and an electric motor for driving positive or reverse rotation of the screw shaft, whichever.

<CIT>, in accordance with its abstract, states: a flight control surface actuator includes a mechanism that enables the actuator translation member to be selectively decoupled from the actuator rotating member. The actuator includes an actuation member, a translation member, an extension member, and a locking member. The actuation member is adapted to receive a drive force and is configured, in response to the drive force, to rotate and cause the translation member to translate. The extension member surrounds at least a portion of the translation member and is configured to be selectively coupled to, and decoupled from, the translation member. The locking member surrounds at least a portion of the extension tube and is movable between a lock position, in which the locking member couples the extension member to the translation member, and a release position, in which the locking member decouples the extension member from the translation member. <CIT>, in accordance with its abstract, states: an electromechanical actuating assembly can have a redundant design with a first electric motor providing actuator-moving power via a first drive train and a second electric motor providing actuator-moving power via a second drive train. A first decoupling train can transmit decoupling power to decouple the first drive train from the actuator and a second decoupling train for transmit decoupling power to decouple the second drive train from the actuator. The assembly is operable in a fault-tolerant mode wherein actuator-moving power is transferred only through one drive train and the other drive train is decoupled from the actuator. <CIT>, in accordance with its abstract, states: a vehicle, having a fixed supporting structure and a load movable relative thereto, a jam tolerant actuating system, a method for controlling this system including: Locating a physical coupling/decoupling mechanism between the load and an actuator assembly as close as practicable to the load; constructing the coupling/uncoupling mechanism to be reversible, and hence testable; and controlling the connection/disconnection via decision making electronics which will detect any system failure by monitoring, at a minimum: actuator main motor load and speed, and actuator output load.

An invention is defined in the appended claims.

An example flap actuation system includes a first actuator, a second actuator, a first drive arm coupled to the first actuator and to a flap, a second drive arm coupled to the second actuator and to the flap, a first cam, and a first output shaft. The first cam is to couple to the first drive arm via the first output shaft during operation of the first actuator to enable the first actuator to actuate the flap via the first drive arm. The example flap actuation system includes a second cam and a second output shaft. The second cam is to couple to the second drive arm via the second output shaft during operation of the second actuator to enable the second actuator to actuate the flap via the second drive arm. The first cam is to be uncoupled from the first drive arm in response to a failure of the first actuator. The second actuator is to actuate the flap via the first drive arm and the second drive arm in response to the failure of the first actuator.

An example aircraft includes a flap, a first actuator, a second actuator, a first drive arm coupled to the flap, a second drive arm coupled to the flap, a first coupler to selectively couple the first actuator to the flap via the first drive arm, and a second coupler to selectively couple the second actuator to the flap via the second drive arm.

An example system includes a first actuator, a second actuator, a drive arm coupled to a flap of a vehicle, a coupler disposed between the first actuator and the drive arm. The coupler includes a cam. The cam is to selectively couple with the drive arm to operatively couple the first actuator to the drive arm. The example system includes a controller to control the coupling of the first actuator to the drive arm via the coupler. The controller to instruct the second actuator to drive movement of the flap when the cam is uncoupled from the drive arm.

The figures are not to scale. Instead, the thickness of the layers or regions may be enlarged in the drawings. In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. Connection references (e.g., attached, coupled, connected, and joined) are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and in fixed relation to each other.

Some air vehicles, such as an aircraft, include airflow control surfaces such as a flap coupled to a wing of the aircraft. The flap can be selectively actuated to affect behavior of the aircraft during one or more stages of flight, such as takeoff and/or landing. For instance, the flap can be extended during takeoff or landing to increase lift of the wing. When the aircraft is in a cruise stage of flight, the flap can be retracted to reduce drag. Movement of the flap can be controlled by a drive system including actuator(s) (e.g., motor(s)) that cause the flap to move between the extended and retracted positions via mechanical support linkages that operatively couple the actuator(s) to the flap.

Asymmetries in the drive system of the flap resulting from, for instance, performance of the actuator(s), can impart twisting forces on the support linkage(s) of the flap. Flap skew can disrupt the airflow control provided by the flap. For example, angular misalignment between two support linkages of the flap due to skew conditions can result in asymmetry between portions of the flap when the flap is deployed. Some known aircraft include sensor(s) to detect skew conditions at the flap by monitoring for, for instance, misalignment between the support linkages. If a skew condition is detected based on the sensor data, the flap may not be deployed. Although refraining from deploying the flap may prevent skew, the behavior of the aircraft can be affected. For example, the aircraft may land at a higher speed because the flap is not extended to maintain lift and increase drag to slow the aircraft.

Disclosed herein are example dual drive systems for actuating a control surface of an aircraft, such as a flap, that reduce instances of skew conditions and enable the control surface to be actuated in the event of failure of one of the actuators of the drive system. Examples disclosed herein include a first dual drive system to control a first support linkage of a flap and a second dual drive system to control a second support linkage of the flap. The example dual drive systems disclosed herein include a first drive subsystem including a first actuator and a second drive subsystem including a second actuator. In the event of failure of the actuator of one of the drive subsystems, the actuator of the other drive subsystem can be used to control movement of the flap via the support linkage. Thus, in examples disclosed herein, the dual drive system associated with each flap support linkage reduces skew that would otherwise result if one of the support linkages was unable to provide for movement of the flap due to a failed actuator at that support linkage.

In examples disclosed herein, each drive subsystem of the dual drive system includes a coupler that provides for selective, operative coupling between the actuator and a corresponding support linkage of the flap. Example couplers disclosed herein include a cam having teeth and an output shaft having corresponding teeth. The output shaft is operatively coupled to one of the flap support linkages via a drive linkage. During operation of the actuator of, for example, a first drive subsystem of the dual drive system, a drive ring causes the teeth of the cam to engage with the teeth of the output shaft. The coupling of the cam to the output shaft operatively couples the actuator to the drive linkage and, thus, the flap support linkage. The actuator of the first drive subsystem can be used to control movement of the flap via the drive linkage and the support linkage to which the drive linkage is coupled.

In the event of failure of the actuator of, for example, the first drive subsystem, the drive ring of the coupler is no longer driven by the failed actuator. As a result, the teeth of the cam of the coupler do not engage with the teeth of the output shaft. Thus, example couplers disclosed herein prevent an operative coupling between the failed actuator of the first drive subsystem and the drive linkage of the first drive subsystem that couples with the flap support linkage. In such examples, the actuator of the second drive subsystem of the dual drive system can be used to control movement of the flap via the support linkage without interference from the failed actuator of the first drive subsystem. In particular, the drive linkage associated with the first drive subsystem can be controlled by the actuator of the second drive subsystem, as that drive linkage is no longer operatively coupled to the failed actuator. Thus, asymmetries with respect to the drive linkages at the dual drive system including the failed actuator are reduced. Further, in examples disclosed herein, because the actuator of the second drive subsystem is able to control the movement of the flap via the corresponding support linkage, skew is prevented at the flap, as each support linkage of the flap continues to be controlled via an actuator. Thus, example disclosed herein isolate the effects of a failed actuator via dual drive systems that provide for continued control of flap movement.

<FIG> illustrates an example aircraft <NUM> in which the examples disclosed herein may be implemented. In the illustrated example, the aircraft <NUM> includes stabilizers <NUM> and wings <NUM> coupled to a fuselage <NUM>. The wings <NUM> define upper and lower surfaces <NUM>, <NUM> (e.g., upper and lower sides, upper and lower aerodynamic surfaces, etc.), respectively. The wings <NUM> of the aircraft <NUM> have control surfaces <NUM> located along the leading and/or trailing edges of the wings <NUM>. The control surfaces <NUM> may be displaced or adjusted (e.g., angled, etc.) to provide lift during takeoff, landing and/or flight maneuvers. In some examples, the control surfaces <NUM> are operated (i.e., displaced) independently of one another. The control surfaces <NUM> include leading edge flaps <NUM>, leading edge slats <NUM>, upper spoilers <NUM> (e.g., flight spoilers, ground spoilers, upper surface spoilers, etc.), and trailing edge flaps (e.g., rotatable flaps) <NUM>. The control surfaces <NUM> of the illustrated example also include ailerons <NUM> and flaperons <NUM>. In this example, the stabilizers <NUM> include elevators <NUM> and a rudder <NUM>.

To control flight of the aircraft <NUM>, the upper surface spoilers <NUM> of the illustrated example alter the lift and drag of the aircraft <NUM>. The flaps <NUM> alter the lift of the aircraft <NUM>. The ailerons <NUM> and the flaperons <NUM> of the illustrated example alter the roll of the aircraft <NUM>. In this example, the leading edge slats <NUM> alter the lift of the aircraft <NUM>. The control surfaces <NUM> of the illustrated example also play a role in controlling the speed of the aircraft <NUM>. For example, the upper surface spoilers <NUM> may be used for braking of the aircraft <NUM>. Any of the control surfaces <NUM> of the illustrated example may be independently moved (e.g., deflected) to control the load distribution in different directions over the respective wings <NUM>, thereby directing movement of the aircraft <NUM>.

The examples described herein may be applied to control surfaces associated with any of the stabilizers <NUM>, the wings <NUM> and/or any other exterior or outboard structure (e.g., a horizontal stabilizer, a wing strut, an engine strut, a canard stabilizer, slats, etc.) of the aircraft <NUM>. In particular, the wings <NUM> and/or the stabilizers <NUM> may have control surfaces <NUM> that can be adjusted to maneuver the aircraft <NUM> and/or control a speed of the aircraft <NUM>, for example. Additionally or alternatively, in some examples, the fuselage <NUM> has control surfaces, which may be deflected, to alter the flight maneuvering characteristics during cruise and/or takeoff of the aircraft <NUM>. Thus, the discussion of examples disclosed herein in connection with flaps is for illustrated purposes only and does not limit the examples to use with flaps.

<FIG> illustrates an example flap actuation system <NUM> in accordance with teachings of this disclosure. The example flap actuation system <NUM> controls movement of a flap <NUM> between an extended position to increase lift of a wing (e.g., the wing <NUM> of <FIG>) including the flap <NUM> and a retracted position to reduce drag. The example flap actuation system <NUM> includes a first dual drive system <NUM> and a second dual drive system <NUM>. The first dual drive system <NUM> is operatively coupled to the flap <NUM> via a first flap support linkage <NUM>. The second dual drive system <NUM> is operatively coupled to the flap <NUM> via a second flap support linkage <NUM>. The example flap actuation system <NUM> can include additional support linkage(s) and corresponding dual drive system(s) than shown in the example of <FIG>. Also, the spacing between the flap support linkages <NUM>, <NUM> can differ from the example shown in <FIG>.

The first dual drive system <NUM> of <FIG> includes a first drive subsystem <NUM> and a second drive subsystem <NUM>. The first drive subsystem <NUM> includes a first actuator <NUM> (e.g., a servomotor). The first actuator <NUM> is operatively coupled to the first flap support linkage <NUM> via a first cycloidal drive <NUM>, a first coupler <NUM>, and a first drive linkage or arm <NUM>. The second drive subsystem <NUM> includes a second actuator <NUM> (e.g., a servomotor). The second actuator <NUM> is operatively coupled to the first flap support linkage <NUM> via a second cycloidal drive <NUM>, a second coupler <NUM>, and a second drive arm <NUM>.

Similarly, the second dual drive system <NUM> of <FIG> includes a third drive subsystem <NUM> and a fourth drive subsystem <NUM>. The third drive subsystem <NUM> includes a third actuator <NUM> (e.g., a servomotor). The third actuator <NUM> is operatively coupled to the second flap support linkage <NUM> via a third cycloidal drive <NUM>, a third coupler <NUM>, and a third drive arm <NUM>. The fourth drive subsystem <NUM> includes a fourth actuator <NUM> (e.g., a servomotor). The fourth actuator <NUM> is operatively coupled to the second flap support linkage <NUM> via a fourth cycloidal drive <NUM>, a fourth coupler <NUM>, and a fourth drive arm <NUM>.

In operation, power generated by the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> is used to drive movement of the drive arms <NUM>, <NUM>, <NUM>, <NUM> of each drive subsystem <NUM>, <NUM>, <NUM>, <NUM>, which results in movement of the respective flap support linkages <NUM>, <NUM> and, thus, the flap <NUM>. In the example of <FIG>, operation of the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> and, thus, movement of the flap <NUM>, is controlled by a control surface controller <NUM>. The example control surface controller <NUM> is communicatively coupled to the respective actuators <NUM>, <NUM>, <NUM>, <NUM> via one or more wired or wireless communication protocols. As disclosed herein, the control surface controller <NUM> generates instruction(s) that are transmitted to the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> to control movement of the flap <NUM> from a stored position to one or more of an extended position or a drooped position. In some examples, the instruction(s) generated by the control surface controller <NUM> control a speed at which the flap <NUM> is moved, a duration for which the flap <NUM> is in a particular position, etc..

The example flap actuation system <NUM> of <FIG> provides for redundancy in controlling movement of the flap <NUM>, as each flap support linkage <NUM>, <NUM> is controlled by one of the dual drive systems <NUM>, <NUM>. As disclosed herein, the couplers <NUM>, <NUM>, <NUM>, <NUM> of the respective drive subsystems <NUM>, <NUM>, <NUM>, <NUM> of each dual drive system <NUM>, <NUM> can operatively isolate or separate the corresponding actuators <NUM>, <NUM>, <NUM>, <NUM> from the flap <NUM> if there is a failure of one of the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> of a particular drive subsystem <NUM>, <NUM>, <NUM>, <NUM>. For instance, in the event of failure of the first actuator <NUM> of the first drive subsystem <NUM>, the first coupler <NUM> prevents an operative coupling between the first drive arm <NUM> of the first drive subsystem <NUM> and the failed first actuator <NUM>. In such examples, movement of the flap <NUM> via the first flap support linkage <NUM> is controlled by the second actuator <NUM> of the second drive subsystem <NUM>. Because the first drive arm <NUM> is not operatively coupled to the failed first actuator <NUM>, the first drive arm <NUM> can move in response to movement of the second drive arm <NUM> by the second actuator <NUM> (i.e., because of the coupling of each drive arm <NUM>, <NUM> to the first flap support linkage <NUM>). Thus, the first and second drive arms <NUM>, <NUM> can be used to control movement of the first flap support linkage <NUM> and asymmetries within the first dual drive system <NUM> are prevented or substantially reduced. Further, flap skew is prevented or substantially reduced despite failure of the first actuator <NUM>, as the first and second flap support linkages <NUM>, <NUM> can continue to be used to move the flap <NUM> due to the redundancy in actuators <NUM>, <NUM> at the first dual drive system <NUM>.

<FIG> are exploded views of the first drive subsystem <NUM> of the example first dual drive system <NUM> of <FIG>. Although <FIG> are discussed in connection with the example first drive subsystem <NUM> of <FIG>, the second drive subsystem <NUM> of the first dual drive system <NUM> of <FIG> includes the same or substantially the same components as the first drive subsystem <NUM> (e.g., where the component(s) of the second drive subsystem are arranged in a mirror image of the components of the first drive subsystem <NUM>). Also, the third drive subsystem <NUM> and the fourth drive subsystem <NUM> of the second dual drive system <NUM> can include the same or substantially the same component(s) as the first drive subsystem <NUM> shown in <FIG>.

As shown in <FIG>, an output shaft <NUM> of the actuator <NUM> of the first drive subsystem <NUM> couples with the cycloidal drive <NUM>. An output shaft <NUM> of the cycloidal drive <NUM> is received by the first coupler <NUM> to operatively couple the actuator <NUM> to the first coupler <NUM>. In the example of <FIG>, the substantially flat profile of the cycloidal drive <NUM> helps to reduce the form factor of the first drive subsystem <NUM> and, thus, the form factor of the first dual drive system <NUM> as compared to the form factor that would result if another gear type (e.g., a planetary gear) was used. The reduced form factor of the first drive subsystem <NUM> can help offset the additional volume consumed by the use of dual actuators at each flap support linkage <NUM>, <NUM> (<FIG>). In other examples, a planetary gear could be used in lieu of the cycloidal drive to provide for gear reduction that is otherwise provided by the cycloidal drive <NUM> of <FIG>. Alternatively, in other examples, an actuator having increased power could be used to drive the first coupler <NUM> directly, with no means of gear reduction.

As shown in <FIG>, an output shaft <NUM> of the first coupler <NUM> extends through an opening <NUM> defined in a rib <NUM> to enable the output shaft <NUM> to couple with the first drive arm <NUM>. In an example aircraft such as the aircraft <NUM> of <FIG>, the rib <NUM> is one of a plurality of ribs that define a trailing edge of a wing (e.g., the wing <NUM> of <FIG>) that includes the flap <NUM> (<FIG>). The rib(s) <NUM> support trailing edge components of the wing, such as the flap <NUM> and the flap actuation system <NUM> of <FIG>.

In the example of <FIG>, the first drive arm <NUM> includes a brake <NUM>. As disclosed herein, operation of the brake <NUM> is controlled by the control surface controller <NUM> of <FIG>. The brake <NUM> can be activated to, for example, lock the first drive arm <NUM> and, thus the flap <NUM> in a particular position (e.g., when the flap <NUM> is extended). As disclosed herein, in some examples, the brake <NUM> is activated in the event of failure of the first actuator <NUM> to stiffen the first drive arm <NUM> and provide a degree of resistance or control with respect to movement of the first drive arm <NUM> via the second actuator <NUM> of the second drive subsystem <NUM> (<FIG>).

<FIG> are exploded views of the first coupler <NUM> of the first drive subsystem <NUM> of the example first dual drive system <NUM> of <FIG>. Although the first coupler <NUM> of the first drive subsystem <NUM> is shown in <FIG>, the second, third, and fourth couplers <NUM>, <NUM>, <NUM> of the respective second, third, and fourth drive subsystems <NUM>, <NUM>, <NUM> of <FIG> include the same or substantially the same components as the first coupler <NUM> shown in <FIG>.

The example first coupler <NUM> of <FIG> includes a housing <NUM>, a bearing <NUM>, a drive ring <NUM>, a cam <NUM>, a spring <NUM>, and the output shaft <NUM>. The housing <NUM> defines an opening <NUM> to receive the output shaft <NUM> of the cycloidal drive <NUM>. The output shaft <NUM> of the cycloidal drive <NUM> extends through the opening <NUM> in the housing <NUM> and engages the drive ring <NUM>. In the example of <FIG>, teeth <NUM> of the output shaft <NUM> of the cycloidal drive <NUM> engage with corresponding teeth <NUM> of the drive ring <NUM> to enable rotational movement to be transferred from the cycloidal drive <NUM> to the drive ring <NUM>. The bearing <NUM> reduces friction between the drive ring <NUM> and the housing <NUM> during rotation of the drive ring <NUM>.

In the example of <FIG>, the cam <NUM> is disposed between the drive ring <NUM> and the output shaft <NUM>. As shown in <FIG>, the drive ring <NUM> includes a first protrusion <NUM> and a second protrusion <NUM> extending from a body of the drive ring <NUM>. As disclosed herein, the protrusions <NUM>, <NUM> of the drive ring <NUM> are in contact with the cam <NUM> to transfer movement from the drive ring <NUM> to the cam <NUM>. The drive ring <NUM> can include additional or fewer protrusions and/or protrusions having different shapes and/or sizes than the example protrusions <NUM>, <NUM> shown in <FIG>.

As shown in <FIG>, the cam <NUM> includes a set of teeth <NUM> and the output shaft <NUM> includes a set of teeth <NUM>. As shown in <FIG>, the housing <NUM> includes a set of teeth <NUM> defined in an interior of the housing <NUM>. In operation, the cam <NUM> selectively moves between a first position in which the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the housing <NUM> and a second position in which the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the output shaft <NUM>. In particular and as disclosed herein, rotational movement of the drive ring <NUM> causes the cam <NUM> to translate from the first position in which the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the housing <NUM> to the second position in which the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the output shaft <NUM>.

As shown in <FIG>, the spring <NUM> is disposed between the cam <NUM> and the output shaft <NUM>. When the cam <NUM> is in the first position in which the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the housing <NUM>, the spring <NUM> is in an expanded position. In the expanded position, the spring <NUM> helps to maintain the position of the cam <NUM> in the housing <NUM> and, thus, the engagement between the teeth <NUM> of the housing <NUM> and the teeth <NUM> of the cam <NUM>. When the cam <NUM> moves to the second position in which the teeth <NUM> of the cam <NUM> engage with the teeth <NUM> of the output shaft <NUM>, the spring <NUM> is compressed as a result of the translation of the cam <NUM>.

<FIG> illustrate the relationship between the drive ring <NUM>, the cam <NUM>, and the output shaft <NUM> of the example first coupler <NUM> of <FIG>. For clarity, the housing <NUM> is not shown in <FIG>.

In <FIG>, the cam <NUM> is in the first position in which the teeth <NUM> are engaged with the teeth <NUM> of the housing <NUM> (<FIG>). As shown in <FIG>, the cam <NUM> includes one or more ramps <NUM>, or a partially sloped surface(s) defined by a body of the cam <NUM>. During rotation of the drive ring <NUM>, as represented by arrow <NUM> in <FIG>, the protrusion(s) of the drive ring <NUM>, such as the first protrusion <NUM> shown in <FIG>, moves along the ramp <NUM> of the cam <NUM>. The movement of the protrusion <NUM> of the drive ring <NUM> along the ramp <NUM> of the cam <NUM> causes translational movement of the cam <NUM> with respect to the output shaft <NUM>, as represented by arrow <NUM> in <FIG>. As a result of rotational movement of the drive ring <NUM> and corresponding translation of the cam <NUM>, the cam <NUM> moves the from the first position in which the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the housing <NUM> to the second position in which the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the output shaft <NUM> (<FIG>).

As shown in <FIG>, the cam <NUM> includes one or more protrusions or stops <NUM> proximate to the ramp <NUM>. When the protrusion <NUM> (and/or the protrusion <NUM> shown in <FIG>) of the drive ring <NUM> engages with one of the stops <NUM> of the cam <NUM>, rotational movement of the drive ring <NUM> is transferred to the output shaft <NUM> via the coupling between the drive ring <NUM>, the cam <NUM>, and the output shaft <NUM>. The coupling of the protrusion(s) <NUM>, <NUM> of the drive ring <NUM> with the stop(s) <NUM> of the cam <NUM> help to maintain the cam <NUM> in engagement with the output shaft <NUM> and enable rotational movement to be transferred between the drive ring <NUM> and the output shaft <NUM>. Rotation of the output shaft <NUM> causes movement (e.g., pivoting) of the first drive arm <NUM> coupled to the output shaft <NUM> (<FIG>). Thus, the coupling between the drive ring <NUM>, the cam <NUM>, and the output shaft <NUM> enables the actuator <NUM> of the first drive subsystem <NUM> to control movement of the first drive arm <NUM> coupled to the output shaft <NUM> (<FIG>).

<FIG> are cross-sectional views of the example first drive subsystem <NUM> taken along the A-A line of <FIG>. In <FIG>, the first drive subsystem <NUM> is in a first operational state in which the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the housing <NUM>. As shown in <FIG>, the spring <NUM> is in an uncompressed or expanded position to help maintain the engagement between the teeth <NUM> of the cam <NUM> and the teeth <NUM> of the housing <NUM>.

<FIG> illustrates the example first drive subsystem <NUM> in a second operational state in which the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the output shaft <NUM>. As disclosed above, the teeth <NUM> of the cam <NUM> move into engagement with the teeth <NUM> of the output shaft <NUM> via operation of the first actuator <NUM>, which causes rotation of the cycloidal drive <NUM>, rotation of the drive ring <NUM>, and corresponding translation of the cam <NUM>. As shown in <FIG>, when the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the output shaft <NUM>, the spring <NUM> is in a compressed position due to the translational movement of the cam <NUM>.

Referring generally to <FIG>, when the teeth <NUM> of the cam <NUM> of the example first drive subsystem <NUM> of <FIG> are engaged with the teeth <NUM> of the output shaft <NUM>, the first actuator <NUM> is operatively coupled to the first drive arm <NUM> and, thus, the first flap support linkage <NUM> of the flap <NUM>. The first actuator <NUM> controls movement of the first flap support linkage <NUM> via the rotation of the drive ring <NUM>, which causes corresponding rotation of the output shaft <NUM> due the coupling between the drive ring <NUM>, the cam <NUM>, and the output shaft <NUM>. The rotation of the output shaft <NUM> drives movement of the first drive arm <NUM>. Also, the second actuator <NUM> of the second drive subsystem <NUM> of the dual drive system <NUM> is operatively coupled to the second drive arm <NUM> in substantially the same manner as discussed in connection with the first drive subsystem <NUM>. The actuators <NUM>, <NUM> drive movement of the first flap support linkage <NUM> via the drive arms <NUM>, <NUM> to raise or lower the flap <NUM> (i.e., in association with movement of the second flap support linkage <NUM> controlled by the second dual drive system <NUM>).

When the flap <NUM> is in a stored position, the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> do not generate power to move the flap <NUM> (e.g., based on instruction(s) from the control surface controller <NUM>). As such, the drive ring <NUM> of, for example, the first coupler <NUM> of the first drive subsystem <NUM> is no longer driven by the first actuator <NUM>. Because the drive ring <NUM> is not rotating, the coupling between the teeth <NUM> of the cam <NUM> and the teeth <NUM> of the output shaft <NUM> is no longer maintained. As a result, the spring <NUM> expands and pushes against the cam <NUM>, which causes the teeth <NUM> of the cam <NUM> to disengage from the teeth <NUM> of the of the output shaft <NUM> and to re-engage with the teeth <NUM> of the housing <NUM>. As a result, the first actuator <NUM> is no longer operatively coupled to the first drive arm <NUM> and, thus, no longer operatively coupled to the first flap support linkage <NUM> of the flap <NUM>.

The selective coupling between the cam <NUM> and the output shaft <NUM> can be used in the event of failure of the first actuator <NUM> or the first cycloidal drive <NUM> of the first drive subsystem <NUM>. In particular, when the first actuator <NUM> and/or the first cycloidal drive <NUM> are in a failed state, the control surface controller <NUM> instructs the first actuator <NUM> to refrain from generating power. As a result, the first actuator <NUM> does not generate the power that would otherwise cause the drive ring <NUM> to facilitate the coupling between teeth <NUM> of the cam <NUM> and the teeth <NUM> of the output shaft <NUM>. In such examples, because the teeth <NUM> of cam <NUM> are not engaged with the teeth <NUM> of the output shaft <NUM>, the first drive arm <NUM> is not operatively coupled to the first actuator <NUM>. Thus, the first drive arm <NUM> is free to be controlled by the second actuator <NUM> of the second drive subsystem <NUM> of <FIG>. In particular, the first drive arm <NUM> is free to pivot in connection with the pivoting of the second drive arm <NUM> that is controlled by the second actuator <NUM> of the second drive subsystem <NUM> (i.e., due to the coupling of both drive arms <NUM>, <NUM> to the first flap support linkage <NUM>).

Thus, in the event of failure of the first actuator <NUM> and/or the first cycloidal drive <NUM>, the actuator <NUM> of the first drive subsystem <NUM> is operatively isolated or separated from the first drive arm <NUM> and does not interfere with movement of the first flap support linkage <NUM>. Asymmetries in the first drive subsystem <NUM> due to the failed actuator <NUM> and/or the failed cycloidal drive <NUM> are minimized because movement of the first drive arm <NUM> is not prevented by the failed actuator <NUM>. Instead, because the teeth <NUM> of the cam <NUM> of the first coupler <NUM> are not engaged with the teeth <NUM> of the output shaft <NUM>, the first drive arm <NUM> is not operatively coupled to the failed actuator <NUM>. In some examples, the brake <NUM> (<FIG>) of the first drive subsystem <NUM> may be activated (e.g., in response to an instruction by the control surface controller <NUM>) in the event of failure of the first actuator <NUM> to provide a degree of resistance and improve control of movement of the first drive arm <NUM> via the corresponding movement of the second drive arm <NUM> of the second drive subsystem <NUM>.

Further, because the first flap support linkage <NUM> can be controlled by the second actuator <NUM> of the second drive subsystem <NUM> in the event of failure of the first actuator <NUM> and/or the first cycloidal drive <NUM> of the first drive subsystem <NUM>, skew at the flap <NUM> is prevented or substantially reduced as compared to if there was only one actuator controlling the first flap support linkage <NUM>. In such cases, if the single actuator failed, the first flap support linkage <NUM> would not be actuated and skew would result between the portion of the flap <NUM> coupled to the first flap support linkage <NUM> and the portion of the flap <NUM> coupled to the second flap support linkage <NUM> that is actuated by operative or non-failed actuator(s). However, in examples disclosed herein, both flap support linkages <NUM>, <NUM> are movable in the event of failure of one of the actuator(s) <NUM>, <NUM> of the first dual drive system <NUM> and/or one of the actuator(s) <NUM>, <NUM> of the second dual drive system <NUM> because the redundancy of actuators <NUM>, <NUM>, <NUM>, <NUM> in the respective dual drive systems <NUM>, <NUM>.

<FIG> illustrate example operational relationships between the first drive subsystem <NUM> and the second drive subsystem <NUM> during operation of the first actuator <NUM> (<FIG>) of the first drive subsystem <NUM> and the second actuator <NUM> (<FIG>) of the second drive subsystem <NUM>. Although <FIG> are discussed in connection with the first and second drive subsystems <NUM>, <NUM> of the first dual drive system <NUM>, the operational relationships between the third drive subsystem <NUM> and the fourth drive subsystem <NUM> can be substantially the same as the relationships between the first and second drive subsystems <NUM>, <NUM> of the first dual drive system <NUM>.

Also, for illustrative purposes, only the drive ring <NUM> and cam <NUM> of the first drive subsystem <NUM> are shown in <FIG>. Also, for illustrative purposes, only a drive ring <NUM> and a cam <NUM> of the second drive subsystem <NUM> are shown in <FIG>. In the examples of <FIG>, the drive ring <NUM> and the cam <NUM> of the second drive subsystem <NUM> are substantially the same as the drive ring <NUM> and the cam <NUM> of the first drive subsystem <NUM>.

<FIG> illustrates the first drive subsystem <NUM> and the second drive subsystem <NUM> in the first operational state shown in <FIG>. In the disengaged state, the teeth of the respective cams <NUM>, <NUM> of the drive subsystems <NUM>, <NUM> (e.g., the teeth <NUM> of the cam <NUM> of <FIG>) are not engaged with the teeth of the output shaft of each drive subsystem <NUM>, <NUM> (e.g., the teeth <NUM> of the output shaft <NUM> of <FIG>). Rather, the first and second drive subsystems <NUM>, <NUM> are in the first operational state shown in the example of <FIG> (e.g., with the teeth <NUM> of the cam <NUM> in engagement with the teeth <NUM> of the housing <NUM> and the spring <NUM> in the expanded position).

<FIG> illustrates each of the example first and second drive subsystems <NUM>, <NUM> in the second operational state shown in <FIG>. In this state, the teeth of the cam <NUM>, <NUM> of each drive subsystem <NUM>, <NUM> are engaged with the teeth of the output shaft of each drive subsystem <NUM>, <NUM> as shown in <FIG> (e.g., with the spring <NUM> in the compressed position).

<FIG> illustrates operation of the first and second drive subsystems during extension of a flap (e.g., the flap <NUM> of <FIG>). The flap can be extended during, for example, takeoff or landing. In operation, there may be a lag time between when the respective drive rings <NUM>, <NUM> are actuated by the cycloidal drives <NUM>, <NUM> (<FIG>) of each drive subsystem <NUM>, <NUM> and when the cams <NUM>, <NUM> of the respective drive subsystems engage with the corresponding output shafts <NUM>. During operation, the airload on the flap (e.g., the flap <NUM> of <FIG>) may pull the flap back into the retracted position. Because of the lag time with respect to movement of the cam, the airload on the flap could cause the flap to move on its own if the actuators <NUM>, <NUM> of the first dual drive system <NUM> were in the same rotational position during operation. To prevent such an effect, the respective actuators <NUM>, <NUM> of the first and second drive subsystems <NUM>, <NUM> operate in alternating agonist/antagonist roles. For example, during extension of the flap, the first actuator <NUM> is used to drive movement of the first flap support linkage <NUM> (<FIG>) and, thus, acts as an agonist or prime mover to drive movement of the flap. In this example, the second actuator <NUM> of the second drive subsystem acts as an antagonist by providing an opposing torque that helps to control movement of the flap via the first flap support linkage <NUM>. As a result of the opposite rotational arrangement of the actuators <NUM>, <NUM>, any tendency for the flap to move on its own due to airload is eliminated or substantially eliminated because of the generation of opposing torques. In other examples, the second actuator <NUM> of the second drive subsystem acts as the agonist or prime mover during extension of the flap.

<FIG> illustrates operation the first and second drive subsystems during retraction of the flap. To reduce fatigue loads on the first actuator <NUM> of the first drive subsystem <NUM>, the second actuator <NUM> of the second drive subsystem <NUM> serves as the prime mover or agonist to drive movement of the first flap support linkage <NUM> to cause the flap to move from an extended position to a retracted position. In this example, the first actuator <NUM> of the first drive subsystem <NUM> serves as the antagonist by providing an opposing torque that controls movement of the first flap support linkage <NUM> as disclosed above. In other examples, the first actuator <NUM> of the first drive subsystem <NUM> acts as the agonist or prime mover during retraction of the flap.

<FIG> illustrates the first and second drive subsystems <NUM>, <NUM> in the disengaged state in which the teeth of the cams <NUM>, <NUM> are not engaged with the teeth of the output shafts of the respective first and second drive subsystems <NUM>, <NUM>. The first and second drive subsystems <NUM>, <NUM> return to the first operational state shown in the example of <FIG> (i.e., where the teeth <NUM> of the cam <NUM> are in engagement with the teeth <NUM> of the housing <NUM> and the spring <NUM> is in the expanded position). The first and second drive subsystems <NUM>, <NUM> can return to the first operational state during, for example, the cruise stage of the aircraft.

As disclosed herein, in the event of failure of, for instance, the first actuator <NUM> of the first drive subsystem <NUM>, the first actuator <NUM> no longer generates power. Thus, the cam <NUM> of the first drive subsystem <NUM> does not engage with the output shaft <NUM> of the first drive subsystem <NUM>. In such examples, the second actuator <NUM> of the second drive subsystem <NUM> controls operation of the flap during extension and/or retraction of the flap. As such, in the examples of <FIG>, the first drive subsystem <NUM> would remain in the first operational state of <FIG>. The second drive subsystem <NUM> would move to the second operational state shown in <FIG> to extend and retract the flap via the operative coupling between the second actuator <NUM> of the second drive subsystem <NUM> and the second drive arm <NUM>.

Conversely, in the event of failure of the second actuator <NUM> of the second drive subsystem <NUM>, the second actuator <NUM> no longer generates power. As such, the cam <NUM> of the second drive subsystem <NUM> does not engage with the output shaft of the second drive subsystem <NUM> and the second drive subsystem <NUM> would remain in the first operational state of <FIG>. In such examples, the first actuator <NUM> of the first drive subsystem <NUM> controls operation of the flap during extension and/or retraction of the flap. The first drive subsystem <NUM> would move to the second operational state shown in <FIG> to extend and retract the flap via the operative coupling between the actuator <NUM> of the second drive subsystem <NUM> and the second drive arm <NUM>.

Although <FIG> are primarily discussed in connection with the example first drive subsystem <NUM> of <FIG>, examples disclosed herein can apply to any of the second, third, and/or fourth drive subsystems <NUM>, <NUM>, <NUM> of the first and/or second dual drive systems <NUM>, <NUM>.

<FIG> is a block diagram of an example implementation of the control surface controller <NUM> of <FIG>. As mentioned above, the control surface controller <NUM> is constructed to generate instruction(s) that are transmitted to the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> of the drive subsystems <NUM>, <NUM>, <NUM>, <NUM> of the example dual drive systems <NUM>, <NUM> of <FIG> to control movement of the flap <NUM>. In the example of <FIG>, the control surface controller <NUM> is implemented by one or more processors (e.g., processor(s) on-board the aircraft including the flap <NUM>) and/or cloud-based device(s) (e.g., server(s), processor(s), and/or virtual machine(s)).

The example control surface controller <NUM> includes an actuator controller <NUM>. The actuator controller <NUM> of <FIG> provides means for controlling operation of the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> of the drive subsystems <NUM>, <NUM>, <NUM>, <NUM> of the example dual drive systems <NUM>, <NUM> of <FIG>. For example, the actuator controller <NUM> generates instructions that cause the actuators to generate power that is used to drive movement of the flap <NUM> between a stored position and an extended position. In some examples, the actuator controller <NUM> instructs the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> to generate power based on user input(s) received at flight control system(s) in communication with the control surface controller <NUM>. The user input(s) can include instructions for the flap <NUM> to move to a particular position. In some examples, the actuator controller <NUM> instructs the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> to refrain from generating power when, for example, the flap <NUM> is in the stored position. In some examples, the actuator controller <NUM> of <FIG> controls operation of the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> with respect to which actuator(s) <NUM>, <NUM>, <NUM>, <NUM> within a particular drive subsystem <NUM>, <NUM>, <NUM>, <NUM> operate as the prime mover during movement of the flap <NUM> and which actuator(s) <NUM>, <NUM>, <NUM>, <NUM> act as the antagonist.

The actuator controller <NUM> of the example control surface controller <NUM> of <FIG> controls operation of the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> based on one or more actuator operation rule(s) <NUM>. The actuator operation rule(s) <NUM> can be defined by one or more user inputs and stored in a database <NUM>. In some examples, the example control surface controller <NUM> includes the database <NUM>. In other examples, the database <NUM> is located external to the control surface controller <NUM> in a location accessible to the controller, as shown in <FIG>.

The example control surface controller <NUM> of <FIG> includes an actuator failure detector <NUM>. The actuator failure detector <NUM> detects a failure state at respective ones of the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> based on data generated by, for instance, sensor(s) of the actuator(s) <NUM>, <NUM>, <NUM>, <NUM>. For example, if an output of a sensor of a particular actuator <NUM>, <NUM>, <NUM>, <NUM> does not satisfy a threshold value or if an output value of the sensor does not change within a threshold period of time, the actuator failure detector <NUM> detects a failure condition at that actuator <NUM>, <NUM>, <NUM>, <NUM>. The actuator failure detector <NUM> can determine that the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> are in a failed state based on the actuator operation rule(s) <NUM> stored in the database <NUM>. The actuator operation rule(s) <NUM> can define expected output(s) for the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> that are used by the actuator failure detector <NUM> to determine that the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> are in a failed state (e.g., based on comparison(s) of actual output(s) of the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> to expected output(s)).

In the example of <FIG>, if the actuator failure detector <NUM> detects that one or more of the actuators <NUM>, <NUM>, <NUM>, <NUM> have failed, the actuator failure detector <NUM> communicates the failed state of the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> to the actuator controller <NUM>. In response, the actuator controller <NUM> prevents the failed actuator(s) <NUM>, <NUM>, <NUM>, <NUM> from generating power (e.g., by instructing the failed actuator(s) <NUM>, <NUM>, <NUM>, <NUM> to power down, refraining from activating the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> if the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> are already powered down, etc.). As a result, because the failed actuator(s) <NUM>, <NUM>, <NUM>, <NUM> do not generate power, the cam of the <NUM> of the first coupler <NUM> of the respective drive subsystems <NUM>, <NUM>, <NUM>, <NUM> does not engage with the corresponding output shaft <NUM> of the drive subsystems <NUM>, <NUM>, <NUM>, <NUM>. Thus, the first drive arm <NUM> of the respective drive subsystems <NUM>, <NUM>, <NUM>, <NUM> including the failed actuator <NUM>, <NUM>, <NUM>, <NUM> is free to be actuated via the other (non-failed) actuator <NUM>, <NUM>, <NUM>, <NUM> of the corresponding dual drive system <NUM>, <NUM>, as disclosed herein.

The example control surface controller <NUM> of <FIG> includes a cycloidal drive failure detector <NUM>. The cycloidal drive failure detector <NUM> detects a failure state at one or more of the cycloidal drive(s) <NUM>, <NUM>, <NUM>, <NUM> based on, for example, one or more cycloidal drive operation rule(s) <NUM> stored in the database <NUM> and data generated by sensor(s) associated with the cycloidal drive(s) <NUM>, <NUM>, <NUM>, <NUM> and/or the sensor(s) associated with the corresponding actuator(s) <NUM>, <NUM>, <NUM>, <NUM>. The cycloidal drive operation rule(s) <NUM> can be defined by user input(s) and include expected speeds and/or positions of the cycloidal drive(s) <NUM>, <NUM>, <NUM>, <NUM> during operation.

In the example of <FIG>, if the cycloidal drive failure detector <NUM> detects that one or more of the cycloidal drive(s) <NUM>, <NUM>, <NUM>, <NUM> have failed, the cycloidal drive failure detector <NUM> communicates the failed state of the cycloidal drive(s) <NUM>, <NUM>, <NUM>, <NUM> to the actuator controller <NUM>. In response, the actuator controller <NUM> prevents the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> associated with the failed cycloidal drive(s) <NUM>, <NUM>, <NUM>, <NUM> from generating power (e.g., by instructing the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> to power down, refraining from activating the actuator(s) <NUM>, <NUM>, <NUM>, <NUM>, etc.). As a result, because the actuator(s) <NUM>, <NUM>, <NUM>, <NUM> do not generate power, the failed cycloidal drive <NUM>, <NUM>, <NUM>, <NUM> does not rotate and, thus, does not drive movement of the drive ring <NUM>. Therefore, the cam <NUM> of the first coupler <NUM> of the respective drive subsystems <NUM>, <NUM>, <NUM>, <NUM> does not engage with the output shaft <NUM> of the drive subsystems <NUM>, <NUM>, <NUM>, <NUM>. Thus, the first drive arm <NUM> of the respective drive subsystems <NUM>, <NUM>, <NUM>, <NUM> including the failed cycloidal drive <NUM>, <NUM>, <NUM>, <NUM> is free to be actuated via the other actuator <NUM>, <NUM>, <NUM>, <NUM> of the corresponding dual drive system <NUM>, <NUM>, as disclosed herein.

The example control surface controller <NUM> of <FIG> includes a brake activator <NUM>. The brake activator <NUM> provides means for controlling the activation or the release of the brake <NUM> of the respective drive subsystems <NUM>, <NUM>, <NUM>, <NUM>. In some examples, the brake activator <NUM> generates instructions that cause the brake <NUM> to move from a released position to an activated position to support the first drive arm <NUM> when the flap <NUM> is in, for example, a raised position and to lock the first drive arm <NUM> and, thus, the flap <NUM> into a particular position. In some examples, the brake activator <NUM> generates instructions that cause the brake <NUM> to move from the activated position to a released position during, for instance, movement of the flap from the raised position to a retracted or stored position. The brake activator <NUM> controls the brake <NUM> based on one or more brake activation rule(s) <NUM> defined by user input(s) and stored in the database <NUM>.

In some examples, the brake activator <NUM> instructs the brake <NUM> of a particular drive subsystem <NUM>, <NUM>, <NUM>, <NUM> to move from a released position to an activated position when the actuator failure detector <NUM> detects that one of the actuators <NUM>, <NUM>, <NUM>, <NUM> of the drive subsystem <NUM>, <NUM>, <NUM>, <NUM> has failed and/or when the cycloidal drive failure detector <NUM> detects that one of the cycloidal drives <NUM>, <NUM>, <NUM>, <NUM> has failed. In such examples, activating the brake <NUM> of the drive subsystem <NUM>, <NUM>, <NUM>, <NUM> including the failed actuator <NUM>, <NUM>, <NUM>, <NUM> and/or the failed cycloidal drive <NUM>, <NUM>, <NUM>, <NUM> provides for a degree of resistance and control of the first drive arm <NUM> of the drive subsystem <NUM>, <NUM>, <NUM>, <NUM> when the first drive arm <NUM> is actuated via the other actuator <NUM>, <NUM>, <NUM>, <NUM> of the dual drive system <NUM>, <NUM>.

While an example manner of implementing the control surface controller <NUM> of <FIG> is illustrated in <FIG>, one or more of the elements, processes and/or devices illustrated in <FIG> may be combined, divided, re-arranged, omitted, eliminated and/or implemented in any other way. Further, the example actuator controller <NUM>, the example database <NUM>, the example actuator failure detector <NUM>, the example cycloidal drive failure detector <NUM>, the example brake activator <NUM> and/or, more generally, the example control surface controller <NUM> of <FIG> may be implemented by hardware, software, firmware and/or any combination of hardware, software and/or firmware. Thus, for example, any of the example actuator controller <NUM>, the example database <NUM>, the example actuator failure detector <NUM>, the example cycloidal drive failure detector <NUM>, the example brake activator <NUM> and/or, more generally, the example control surface controller <NUM> could be implemented by one or more analog or digital circuit(s), logic circuits, programmable processor(s), programmable controller(s), graphics processing unit(s) (GPU(s)), digital signal processor(s) (DSP(s)), application specific integrated circuit(s) (ASIC(s)), programmable logic device(s) (PLD(s)) and/or field programmable logic device(s) (FPLD(s)). When reading any of the apparatus or system claims of this patent to cover a purely software and/or firmware implementation, at least one of the example actuator controller <NUM>, the example database <NUM>, the example actuator failure detector <NUM>, the example cycloidal drive failure detector <NUM>, and/or the example brake activator <NUM> is/are hereby expressly defined to include a non-transitory computer readable storage device or storage disk such as a memory, a digital versatile disk (DVD), a compact disk (CD), a Blu-ray disk, etc. including the software and/or firmware. Further still, the example control surface controller <NUM> of <FIG> may include one or more elements, processes and/or devices in addition to, or instead of, those illustrated in <FIG>, and/or may include more than one of any or all of the illustrated elements, processes and devices. As used herein, the phrase "in communication," including variations thereof, encompasses direct communication and/or indirect communication through one or more intermediary components, and does not require direct physical (e.g., wired) communication and/or constant communication, but rather additionally includes selective communication at periodic intervals, scheduled intervals, aperiodic intervals, and/or one-time events.

<FIG> is a flowchart of an example method for assembling a drive subsystem (e.g., the drive subsystem <NUM>, <NUM>, <NUM>, <NUM> of <FIG>) of a dual drive system (e.g., the dual drive system <NUM>, <NUM> of <FIG>) for actuating a control surface (e.g., the flap <NUM> of <FIG>) of an air vehicle in accordance with teachings of this disclosure. The example method <NUM> begins with coupling an actuator to a cycloidal drive (block <NUM>). For example, the actuator <NUM> of <FIG> is coupled to the cycloidal drive <NUM> via the output shaft <NUM> of the actuator <NUM>.

The example method <NUM> includes coupling means for operatively coupling the actuator to a drive arm of the drive subsystem to the cycloidal drive (block <NUM>). For example, the first coupler <NUM> of <FIG> is coupled to the cycloidal drive <NUM> via the output shaft <NUM> of the cycloidal drive <NUM>. In this example, the output shaft <NUM> of the cycloidal drive <NUM> extends through an opening <NUM> in the housing <NUM> of the first coupler <NUM>. The output shaft <NUM> of the cycloidal drive <NUM> couples with the drive ring <NUM> of the first coupler <NUM>. In particular, the teeth of the output shaft <NUM> of the cycloidal drive <NUM> engage with the teeth <NUM> of the drive ring <NUM> to operatively couple the actuator <NUM> to the first coupler <NUM>.

The example method <NUM> includes coupling an output shaft of the means for operatively coupling to a drive arm of the drive subsystem (block <NUM>). For example, the output shaft <NUM> of the first coupler <NUM> is coupled to first drive arm <NUM> of the example drive subsystem <NUM> of <FIG>. In some examples, the output shaft <NUM> extends through an opening <NUM> in the rib <NUM> of first drive subsystem <NUM> to couple with the first drive arm <NUM>.

The example method <NUM> includes coupling a brake to the drive arm (block <NUM>). For example, the brake <NUM> of <FIG> is coupled to the first drive arm <NUM> to lock the first drive arm <NUM> in a particular position.

Although the example method <NUM> is described with reference to the flowchart illustrated in <FIG>, many other methods of assembling a drive subsystem of a dual drive system may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. Similarly, additional operations may be included in the example method of <FIG> before, in between, or after the blocks shown in <FIG>.

A flowchart representative of example hardware logic, machine readable instructions, hardware implemented state machines, and/or any combination thereof for implementing the control surface controller <NUM> of <FIG> and/or <NUM> is shown in <FIG>. The machine readable instructions may be one or more executable programs or portion(s) of an executable program for execution by a computer processor such as the processor <NUM> shown in the example processor platform <NUM> discussed below in connection with <FIG>. The program may be embodied in software stored on a non-transitory computer readable storage medium such as a CD-ROM, a floppy disk, a hard drive, a DVD, a Blu-ray disk, or a memory associated with the processor <NUM>, but the entire program and/or parts thereof could alternatively be executed by a device other than the processor <NUM> and/or embodied in firmware or dedicated hardware. Further, although the example program is described with reference to the flowchart illustrated in <FIG>, many other methods of implementing the example control surface controller <NUM> may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. Additionally or alternatively, any or all of the blocks may be implemented by one or more hardware circuits (e.g., discrete and/or integrated analog and/or digital circuitry, a FPGA (field-programmable gate array), an ASIC, a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to perform the corresponding operation without executing software or firmware.

The machine readable instructions described herein may be stored in one or more of a compressed format, an encrypted format, a fragmented format, a compiled format, an executable format, a packaged format, etc. Machine readable instructions as described herein may be stored as data (e.g., portions of instructions, code, representations of code, etc.) that may be utilized to create, manufacture, and/or produce machine executable instructions. For example, the machine readable instructions may be fragmented and stored on one or more storage devices and/or computing devices (e.g., servers). The machine readable instructions may require one or more of installation, modification, adaptation, updating, combining, supplementing, configuring, decryption, decompression, unpacking, distribution, reassignment, compilation, etc. in order to make them directly readable, interpretable, and/or executable by a computing device and/or other machine. For example, the machine readable instructions may be stored in multiple parts, which are individually compressed, encrypted, and stored on separate computing devices, wherein the parts when decrypted, decompressed, and combined form a set of executable instructions that implement a program such as that described herein.

In another example, the machine readable instructions may be stored in a state in which they may be read by a computer, but require addition of a library (e.g., a dynamic link library (DLL)), a software development kit (SDK), an application programming interface (API), etc. in order to execute the instructions on a particular computing device or other device. In another example, the machine readable instructions may need to be configured (e.g., settings stored, data input, network addresses recorded, etc.) before the machine readable instructions and/or the corresponding program(s) can be executed in whole or in part. Thus, the disclosed machine readable instructions and/or corresponding program(s) are intended to encompass such machine readable instructions and/or program(s) regardless of the particular format or state of the machine readable instructions and/or program(s) when stored or otherwise at rest or in transit.

As mentioned above, the example processes of <FIG> may be implemented using executable instructions (e.g., computer and/or machine readable instructions) stored on a non-transitory computer and/or machine readable medium such as a hard disk drive, a flash memory, a read-only memory, a compact disk, a digital versatile disk, a cache, a random-access memory and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended time periods, permanently, for brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term non-transitory computer readable medium is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media.

<FIG> is a flowchart of an example method <NUM> to control the selective, operative coupling of actuators (e.g., the actuators <NUM>, <NUM>, <NUM>, <NUM> of <FIG>) of a dual drive system (e.g., the dual drive system <NUM>, <NUM> of <FIG>) to corresponding drive arms (e.g., the drive arms <NUM>, <NUM>, <NUM>, <NUM> of <FIG>) for controlling actuation of a control surface (e.g., the flap <NUM>) of an air vehicle. The example method <NUM> can be implemented by the example control surface controller <NUM> of <FIG> and/or <NUM>.

The example method <NUM> begins with identifying that a first actuator and associated first cycloidal drive of the dual drive system and a second actuator and associated second cycloidal drive of the dual drive system are operative state and there are no failure conditions (block <NUM>). For example, the actuator failure detector <NUM> of the control surface controller <NUM> confirms that the first and second actuators <NUM>, <NUM> of the first drive subsystem <NUM> are both operative based on data received from the actuator(s) <NUM>, <NUM> (e.g., sensor data) and the actuator operation rule(s) <NUM> stored in the database <NUM>. The cycloidal drive failure detector <NUM> of the control surface controller <NUM> confirms that the first cycloidal drive <NUM> associated with the first actuator <NUM> and the second cycloidal drive <NUM> associated with the second actuator <NUM> are both operative based on data received from the cycloidal drive(s) <NUM>, <NUM> and/or the actuator(s) <NUM>, <NUM> and the cycloidal drive operation rule(s) <NUM> stored in the database <NUM>.

When both actuators and corresponding cycloidal drives of the dual drive system are in an operative state, the actuators are used to actuate the control surface of the air vehicle via the corresponding drive arms (block <NUM>). For example, the actuator controller <NUM> of the control surface controller <NUM> instructs the actuators <NUM>, <NUM> of the first dual drive subsystem <NUM> to generate power to move the drive arms <NUM>, <NUM> and, thus, the flap <NUM> based on the actuator operation rule(s) <NUM>. When the first actuator <NUM> is operative, power from the first actuator <NUM> drives the cam <NUM> of the first coupler <NUM> of the first drive subsystem <NUM> from the first position in which the teeth <NUM> of the cam <NUM> engage the teeth <NUM> of the housing <NUM> to the second position in which the teeth <NUM> of the cam <NUM> engage the teeth <NUM> of the output shaft <NUM> (e.g., via movement of the cycloidal drive <NUM> and the drive ring <NUM>). As a result of the engagement of the teeth <NUM> of the cam <NUM> with the teeth <NUM> of the output shaft <NUM>, the first actuator <NUM> is operatively coupled to the first drive arm <NUM>. Similarly, power generated by the second actuator <NUM> is used to drive the cam of the coupler <NUM> of the second drive subsystem <NUM> into engagement with the output shaft of the second drive subsystem <NUM> to operatively couple the second actuator <NUM> to the second drive arm <NUM>. In some examples, the actuator operation rule(s) <NUM> determine which of the actuators <NUM>, <NUM> are to operate as the prime mover during movement of the flap <NUM> and which of the actuators <NUM>, <NUM> are to act as the antagonist during movement of the flap <NUM>.

In some examples, the brake activator <NUM> activates the respective brakes associated with the drive arms <NUM>, <NUM> (e.g., the brake <NUM>) to lock the drive arms <NUM>, <NUM> and. thus, the flap <NUM> in a particular position.

In some examples of the method <NUM>, a failure condition is detected at (a) the first actuator or the first cycloidal drive of the first drive subsystem of the dual drive system or (b) the second actuator or the second cycloidal drive of the second drive subsystem of the dual drive system (block <NUM>). For example, the actuator failure detector <NUM> of the example control surface controller <NUM> of <FIG> can determine that the first actuator <NUM> of the first drive subsystem <NUM> or the second actuator <NUM> of the second drive subsystem <NUM> is in a failed state (e.g., based on outputs received from the respective actuator(s)). In other examples, the cycloidal drive failure detector <NUM> of the example control surface controller <NUM> of <FIG> determines that the first cycloidal drive <NUM> of the first drive subsystem <NUM> or the second cycloidal drive <NUM> of the second drive subsystem <NUM> is in a failed state (e.g., based on sensor data generated for the respective cycloidal drives <NUM>, <NUM>).

If a failure state is detected at block <NUM>, the example method <NUM> includes preventing the operative coupling between the actuator of the drive subsystem associated with the failure condition and the corresponding drive arm associated with the drive subsystem. For example, if the failure condition is associated with the first actuator or the first cycloidal drive of the first drive subsystem, the example method <NUM> includes preventing the generation of power by the first actuator to prevent the operative coupling between the first actuator and the first drive arm (block <NUM>). For example, the actuator controller <NUM> of the control surface controller <NUM> prevents the first actuator <NUM> from generating power. As a result, the cycloidal drive <NUM> does not drive the drive ring <NUM> of the first coupler <NUM>. Thus, the cam <NUM> remains in the first position in which the teeth <NUM> of the cam <NUM> are engaged with the teeth <NUM> of the housing <NUM> and is not driven by the drive ring <NUM> to engage with the teeth <NUM> of the output shaft <NUM>. As such, the first actuator <NUM> does not operatively couple with the first drive arm <NUM>.

In such examples, the method <NUM> includes actuating the first drive arm via the second actuator of the second drive subsystem (block <NUM>). For example, the second actuator <NUM> drives movement of the second drive arm <NUM>, which is coupled to the first flap support linkage <NUM>. Because the first drive arm <NUM> is not operatively coupled to the first actuator <NUM>, the first drive arm <NUM> also moves as a result of movement of the second drive arm <NUM> and the coupling of the first drive arm <NUM> to the first flap support linkage <NUM>.

In such some examples, the method <NUM> includes applying a brake associated with the first drive arm (block <NUM>). For example, the brake activator <NUM> activates the brake <NUM> of the first drive arm <NUM> to facilitate control of the movement of the first drive arm <NUM> via the second actuator <NUM>.

In the example of <FIG>, if the failure is detected at the second actuator or the second cycloidal drive of the second drive subsystem (block <NUM>), the example method <NUM> includes preventing the generation of power by the second actuator to prevent the operative coupling between the second actuator and the second drive arm. For example, the actuator controller <NUM> prevents the second actuator <NUM> from generating power and, thus, prevents the second actuator <NUM> from operatively coupling to the second drive arm <NUM> via the second cycloidal drive <NUM> and the first coupler <NUM> of the second drive subsystem <NUM> (block <NUM>).

In such examples, the method <NUM> includes actuating the second drive arm via the first actuator of the first drive subsystem (block <NUM>). For example, the second drive arm <NUM> pivots during actuation of the first drive arm <NUM> by the first actuator <NUM> and resulting movement of the first flap support linkage <NUM>. In some such examples, the method <NUM> includes applying a brake associated with the second drive arm (block <NUM>). For example, the brake activator <NUM> activates the brake <NUM> of the second drive arm <NUM> to facilitate control of the movement of the second drive arm <NUM> via the first actuator <NUM>.

The example method <NUM> of <FIG> ends when the control surface is returned to its stored position (block <NUM>).

<FIG> is a block diagram of an example processor platform <NUM> structured to execute the instructions of <FIG> to implement the control surface controller <NUM> of <FIG> and/or <NUM>. The processor platform <NUM> can be, for example, a server, a personal computer, a workstation, a self-learning machine (e.g., a neural network), a mobile device (e.g., a cell phone, a smart phone, a tablet such as an iPad™), a personal digital assistant (PDA), an Internet appliance or any other type of computing device.

For example, the processor <NUM> can be implemented by one or more integrated circuits, logic circuits, microprocessors, GPUs, DSPs, or controllers from any desired family or manufacturer. The hardware processor may be a semiconductor based (e.g., silicon based) device. In this example, the processor implements the example actuator controller <NUM>, the example actuator failure detector <NUM>, the example cycloidal drive failure detector <NUM>, and the example brake activator <NUM>.

The interface circuit <NUM> may be implemented by any type of interface standard, such as an Ethernet interface, a universal serial bus (USB), a Bluetooth® interface, a near field communication (NFC) interface, and/or a PCI (peripheral component interconnect) express interface.

Coded instructions <NUM> of <FIG> may be stored in the mass storage device <NUM>, in the volatile memory <NUM>, in the non-volatile memory <NUM>, and/or on a removable non-transitory computer readable storage medium such as a CD or DVD.

Claim 1:
A system comprising a flap actuation system (<NUM>), a flap (<NUM>), and a flap support linkage (<NUM>) connected to the flap, the flap actuation system comprising:
a first actuator (<NUM>);
a second actuator (<NUM>);
a first drive arm (<NUM>) coupled to the first actuator, and coupled to the flap via the flap support linkage;
a second drive arm (<NUM>) coupled to the second actuator, and coupled to the flap via the flap support linkage;
a first cam (<NUM>, <NUM>);
a first output shaft (<NUM>), the first cam to couple to the first drive arm via the first output shaft during operation of the first actuator to enable the first actuator to actuate the flap via the first drive arm;
a second cam (<NUM>, <NUM>);
a second output shaft (<NUM>), the second cam to couple to the second drive arm via the second output shaft during operation of the second actuator to enable the second actuator to actuate the flap via the second drive arm, the first cam uncoupled from the first drive arm in response to a failure of the first actuator, the second actuator to actuate the flap via the second drive arm in response to the failure of the first actuator; and
a controller (<NUM>), the controller configured to control the coupling of the first actuator to the first drive arm via the first cam and to instruct the second actuator to actuate the flap when the first cam is uncoupled from the first drive arm.