Patent Description:
Aircraft typically have brakes on the wheels to slow the aircraft during aborted takeoffs, landings, and/or while taxiing. Additionally, some aircraft employ emergency park brake systems that execute emergency braking and/or maintain a braking force while the aircraft is parked. Conventional brake systems generally include a mechanical linkage (e.g., a cable) that extends between a user brake interface (e.g., a pedal or a handle) and a braking force actuator. These conventional mechanical linkage systems, however, can be difficult and complex to implement. While electrical configurations can be implemented to replace and solve some of the complexities of the mechanical linkage configurations, conventional electrical configurations can be susceptible to uncommanded braking. For example, unintentionally executed, undesired, or uncommanded braking, whether due to user error or component failure, may result in the application of a braking force on the wheels of an aircraft at inopportune times (e.g., during takeoff). Park break systems are disclosed in <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

In various embodiments, the present disclosure provides an emergency park brake system of an aircraft as defined by claim <NUM> and a method of controlling an emergency park brake system as defined by claim <NUM>.

In various embodiments, the emergency park brake system further includes a user input interface, wherein the emergency braking input is a displacement of the user input interface. The emergency park brake system may include a displacement sensor coupled to the user input interface. The displacement sensor may be configured to detect the displacement of the user input interface and generate an emergency braking command based on the displacement of the user input interface. In various embodiments, the emergency park brake system further includes an excitation monitor coupled to the displacement sensor and configured to detect an excitation level of the displacement sensor.

In various embodiments, whether the electromechanical actuator is in power receiving communication with the electrical power interface is based on the emergency braking command and the excitation level of the displacement sensor. In various embodiments, the electromechanical actuator is electrically disconnected from the electrical power interface in response to the displacement of the user input interface being less than a threshold displacement.

Also disclosed herein, according to various embodiments, is an emergency park brake system of an aircraft. The emergency park brake system is defined by the appended claims and includes an electrical power interface configured to receive electrical power from a power source, an electromechanical actuator in selective power receiving communication with the electrical power interface, and a hydraulic brake valve, wherein the electromechanical actuator is mechanically coupled to and configured to selectively actuate the hydraulic brake valve. The emergency park brake system may further include a plurality of discrete hardware controllers interconnected via a first electrical communication pathway and a second electrical communication pathway, wherein the plurality of discrete hardware controllers have instructions stored thereon that cause the emergency park brake system to perform various operations. The various operations include receiving an emergency braking input, determining an emergency braking command based on the emergency braking input, determining a power supply condition based on the emergency braking command, transmitting, via the first electrical communication pathway, the emergency braking command to the electromechanical actuator, and transmitting, based on the power supply condition and via the second electrical communication pathway, electrical power from the electrical power interface to the electromechanical actuator.

In various embodiments, the emergency park brake system further includes a user input interface, wherein the emergency braking input is a displacement of the user input interface. The emergency park brake system may further include a displacement sensor coupled to the user input interface. The displacement sensor may be configured to detect the displacement of the user input interface and generate the emergency braking command based on the displacement of the user input interface. In various embodiments, whether the electromechanical actuator is in power receiving communication with the electrical power interface is based on the emergency braking command.

In various embodiments, the emergency park brake system further includes an excitation monitor coupled to the displacement sensor and configured to detect an excitation level of the displacement sensor. In various embodiments, whether the electromechanical actuator is in power receiving communication with the electrical power interface is based on the emergency braking command and the excitation level of the displacement sensor. In various embodiments, the power supply condition is based on the excitation level of the displacement sensor.

In various embodiments, determining the emergency braking command comprises comparing the displacement of the user input interface with a threshold displacement. In various embodiments, the power supply condition indicates a power disconnection in response to the displacement of the user input interface being less than the threshold displacement. In various embodiments, the power supply condition indicates a power connection in response to the displacement of the user input interface being greater than the threshold displacement.

Also disclosed herein, according to various embodiments, is a method of controlling an emergency park brake system of an aircraft. The method includes, in accordance with the claims, the step of receiving, by an emergency park brake controller, an emergency braking input. The method does way also include determining, by a first electrical communication pathway of the emergency park brake controller, a power connection command based on the emergency braking input. The method further includes determining, by a second electrical communication pathway of the emergency park brake controller, an emergency braking command based on the emergency braking input. The method further includes actuating, by the emergency park brake controller, via an electromechanical actuator, and based on the power connection command and the emergency braking command, a hydraulic brake valve.

In accordance with the claims, actuating the hydraulic brake valve to apply a braking force to wheels of the aircraft is performed in response to the power connection command indicating a power supply condition that indicates a power connection. In accordance with the claims, actuating the hydraulic brake valve includes transmitting, by the emergency park brake controller and via the first electrical communication pathway, the power connection command to the electromechanical actuator. In various embodiments, actuating the hydraulic brake valve includes transmitting, by the emergency park brake controller, based on the power supply condition, and via the second electrical communication pathway, the emergency braking command to the electromechanical actuator.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with this disclosure and the teachings herein without departing from the scope of the invention as defined by the claims.

Referring now to <FIG>, in accordance with various embodiments, an aircraft <NUM> may include landing gear such as main landing gear <NUM>, main landing gear <NUM> and nose landing gear <NUM>. Main landing gear <NUM>, main landing gear <NUM>, and nose landing gear <NUM> may generally support aircraft <NUM> when aircraft <NUM> is not flying, allowing aircraft <NUM> to taxi, take off and land without damage. Main landing gear <NUM> may include wheel 13A and wheel 13B coupled by an axle <NUM>. Main landing gear <NUM> may include wheel 15A and wheel 15B coupled by an axle <NUM>. Nose landing gear <NUM> may include nose wheel 17A and nose wheel 17B coupled by an axle <NUM>. In various embodiments, aircraft <NUM> may comprise any number of landing gears and each landing gear may comprise any number of wheels. Main landing gear <NUM>, main landing gear <NUM>, and nose landing gear <NUM> may each be retracted for flight.

Aircraft <NUM> may also include a primary brake system, which may be applied to a wheel of a landing gear. The primary brake system of aircraft <NUM> may comprise a collection of subsystems that produce output signals for controlling the braking force and/or torque applied at each wheel (e.g., wheel 13A, wheel 13B, wheel 15A, wheel 15B, etc.). The primary brake system may communicate with the brakes of each landing gear (e.g., main landing gear <NUM>, main landing gear <NUM>, and/or nose landing gear <NUM>), and each brake may be mounted to each wheel to apply and release braking force on one or more wheels (e.g., as described above). The brakes of an aircraft <NUM> may include a non-rotatable wheel support, a wheel (e.g., wheel 13A, wheel 13B, wheel 15A, wheel 15B, wheel 17A, and/or wheel 17B) mounted to the wheel support for rotation, and a brake disk stack.

Referring to <FIG>, brake assembly <NUM> may be found on an aircraft, in accordance with various embodiments. Brake assembly <NUM> may, for example, comprise a bogie axle <NUM>, a wheel <NUM> including a hub <NUM> and a wheel well <NUM>, a web <NUM>, a torque take-out assembly <NUM>, one or more torque bars <NUM>, a wheel rotational axis <NUM>, a wheel well recess <NUM>, an actuator <NUM>, multiple brake rotors <NUM>, multiple brake stators <NUM>, a pressure plate <NUM>, an end plate <NUM>, a heat shield <NUM>, multiple heat shield sections <NUM>, multiple heat shield carriers <NUM>, an air gap <NUM>, multiple torque bar bolts <NUM>, a torque bar pin <NUM>, a wheel web hole <NUM>, multiple heat shield fasteners <NUM>, multiple rotor lugs <NUM>, and multiple stator slots <NUM>.

Brake disks (e.g., interleaved rotors <NUM> and stators <NUM>) are disposed in wheel well recess <NUM> of wheel well <NUM>. Rotors <NUM> are secured to torque bars <NUM> for rotation with wheel <NUM>, while stators <NUM> are engaged with torque take-out assembly <NUM>. At least one actuator <NUM> is operable to compress interleaved rotors <NUM> and stators <NUM> for stopping the aircraft. In this example, actuator <NUM> is shown as a hydraulically actuated piston. Pressure plate <NUM> and end plate <NUM> are disposed at opposite ends of the interleaved rotors <NUM> and stators <NUM>. Rotors <NUM> and stators <NUM> can comprise any material suitable for friction disks, including ceramics or carbon materials, such as a carbon/carbon composite.

Through compression of interleaved rotors <NUM> and stators <NUM> between pressure plates <NUM> and end plate <NUM>, the resulting frictional contact slows, stops, and/or prevents rotation of wheel <NUM>. Torque take-out assembly <NUM> is secured to a stationary portion of the landing gear truck such as a bogie beam or other landing gear strut, such that torque take-out assembly <NUM> and stators <NUM> are prevented from rotating during braking of the aircraft.

In various embodiments, and with reference to <FIG>, aircraft <NUM> may also include one or more emergency park brake systems <NUM>. The emergency park brake systems <NUM> of aircraft <NUM> includes an electrical power interface <NUM>, an electromechanical actuator <NUM>, and a hydraulic brake valve <NUM>. The hydraulic brake valve <NUM> may be coupled to one or more wheels <NUM> of the aircraft <NUM>.

As described in greater detail below, the emergency park brake system <NUM> generally controls an emergency or parking braking force/torque that is applied and implemented via a brake assembly (e.g., hydraulic brake valve <NUM>) to each wheel <NUM>, according to various embodiments. The emergency park brake system <NUM> may be separate from, for example, a primary brake system. In various embodiments, various components of the emergency park brake system <NUM>, such as the wheel/brake assembly <NUM>, may be shared with a primary brake system while various other components of the emergency park brake system <NUM>, such as hydraulic brake valve <NUM> or an emergency park brake controller <NUM> described below with reference to <FIG>, are not shared with the primary brake system.

The hydraulic brake valve <NUM>, according to the claims, is actuated via the electromechanical actuator <NUM>. Said differently, the electromechanical actuator <NUM> is mechanically coupled to the hydraulic brake valve <NUM> and may supplant/replace the cable that would be utilized in a conventional hydraulic configuration. For example, the brake system <NUM> may receive an emergency braking input and the electromechanical actuator <NUM> may actuate the hydraulic brake valve <NUM> that controls the fluid pressure in the hydraulic brake valve <NUM>.

In accordance with the claims, the electrical power interface <NUM> is configured to receive electrical power from a power source and the electromechanical actuator <NUM> is in selective power receiving communication with the electrical power interface <NUM>, as indicated by dashed line <NUM>. Said differently, the electromechanical actuator <NUM> is not always connected to the power source via the electrical power interface <NUM>. For example, in order to prevent inadvertent or uncommanded braking, the electromechanical actuator <NUM> may be electrically disconnected from the electrical power interface <NUM> unless a power supply condition is satisfied. In response to the power supply condition being satisfied or in response to the power supply condition indicating a powered connection, the electrical power interface <NUM> may be electrically connected to the electromechanical actuator <NUM> and the electromechanical actuator <NUM> may control braking force applied to the wheels <NUM> via selective actuation of the hydraulic brake valve <NUM> based on a determined braking command (as described in greater detail below).

With with reference to <FIG>, the emergency park brake system <NUM> also includes an emergency park brake controller <NUM>. The emergency park brake controller <NUM> is generally configured to receive an emergency braking input (or park braking input), determine an emergency braking command based on the emergency braking input, and determine the power supply condition, as described in greater detail below. The emergency park brake controller <NUM>, according to various embodiments, is separate from computer systems onboard aircraft <NUM> such as, for example, a brake control unit (BCU), a full authority digital engine control (FADEC), an engine-indicating and crew-alerting system (EICAS), and/or the like. The emergency park brake controller <NUM> may be a component of the electromechanical actuator or may be a standalone computer system separate from overall control system of the aircraft <NUM>. The emergency park brake controller <NUM> may include one or more processors and/or one or more tangible, non-transitory memories and be capable of implementing logic. Each processor can be a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof.

In various embodiments, the processor of the emergency park brake controller <NUM> may be configured to implement various logical operations in response to execution of instructions, for example, instructions stored on the non-transitory memory (e.g., tangible, computer-readable medium). As used herein, the term "non-transitory" is to be understood to remove only propagating transitory signals per se from the claim scope and does not relinquish rights to all standard computer-readable media that are not only propagating transitory signals per se.

In various embodiments, the term "emergency park brake controller <NUM>" refers to a plurality of discrete hardware controllers interconnected via a first electrical communication pathway and a second electrical communication pathway. The plurality of discrete hardware controllers may have instructions stored thereon that cause the emergency park brake system to perform the operations described below.

In various embodiments, and with continued reference to <FIG>, the emergency park brake controller <NUM> may receive an emergency braking input via user displacement of a pedal or a handle, as described in greater detail below with reference to <FIG>. The emergency park brake controller <NUM> generates an emergency braking command based on the emergency braking input, according to various embodiments. The emergency park brake controller <NUM> also generates a power supply condition that is based on the emergency braking command, according to various embodiments. As mentioned above, the power supply condition may indicate a "power disconnection" between the electrical power interface <NUM> and the electromechanical actuator <NUM> or the power supply condition may indicate a "power connection" between the electrical power interface <NUM> and the electromechanical actuator <NUM>.

In accordance with the claims, the emergency park brake controller <NUM> includes a first electrical communication pathway <NUM> and a second electrical communication pathway <NUM>. The emergency park brake controller <NUM> may send a power connection command via the first electrical communication pathway <NUM> to the electrical power interface <NUM>. The power connection demand may indicate whether the selective electrical connection <NUM> between electrical power interface and the electromechanical actuator <NUM> is to be electrically connected or electrically disconnected. The emergency park brake controller <NUM> may send the emergency braking command to the electromechanical actuator <NUM> via the second electrical communication pathway <NUM>. The two separate electrical communication pathways <NUM>, <NUM> provide a degree of redundancy to ensure that a braking force is intended and desired to be applied to the wheels <NUM>. Said differently, and according to various embodiments, the electromechanical actuator <NUM> only actuates the hydraulic brake valve <NUM> to effectuate a braking force on the wheels <NUM> in response to the power supply condition being satisfied (e.g. indicating a power connection) and in response to the generated emergency braking command calling for application of braking force.

In various embodiments, and with reference to <FIG>, the emergency park brake system <NUM> further includes a user input interface <NUM> and a displacement sensor <NUM>. In various embodiments, the emergency braking input may be received in the form of a displacement of the user input interface <NUM>. The user input interface <NUM> of the emergency park brake system <NUM> is configured to receive actuation/input from a user. For example, the user input interface <NUM> may be an emergency brake handle, level, or other movable mechanical component, that is integrated within a cockpit of the aircraft <NUM>. In various embodiments, the user input interface <NUM> is separate from the cockpit. In various embodiments, the user input interface <NUM> may be a remote lever or other user interface that is suitable for being actuated by a remote user (e.g., unmanned aircraft). The displacement sensor <NUM>, according to various embodiments, is coupled to the user input interface <NUM> and is configured to detect displacement of the user input interface <NUM> from a neutral or "zero" position and communicate the detected displacement to the emergency park brake controller <NUM>.

The displacement sensor <NUM> may include any suitable sensor, such as, for example, a linear variable differential transformer (LVDT), a rotary variable differential transformer (RVDT), a potentiometer, a magnetic encoder, and/or the like. The displacement sensor <NUM> may generate and transmit the detected displacement as a variable brake signal (e.g., representative of a percentage of displacement of the user input interface <NUM> from a zero, reference position to a maximum reference position).

In various embodiments, the emergency park brake controller <NUM> is configured to generate the emergency braking by comparing the detected displacement with a predetermined threshold displacement. The threshold displacement may refer to a predetermined minimum displacement value (e.g., a "deadband" threshold). For example, if the detected displacement of the user input interface <NUM> is less than the threshold displacement, the emergency braking command generated by the emergency park brake controller <NUM> may indicate a null demand/command. That is, if the user input interface <NUM> has not been actuated or if the user input interface <NUM> is not sufficiently actuated (displaced), a signal indicating "no braking" may be sent by the emergency park brake controller <NUM> to the electromechanical actuator <NUM>, according to various embodiments. However, if the user input interface <NUM> is sufficiently actuated (displaced) beyond the threshold displacement, the emergency braking command indicates a braking force to be actuated and thus a signal indicating "braking" is sent to the electromechanical actuator <NUM>.

In various embodiments, the threshold displacement is about <NUM>% from a zero position of the user input interface <NUM> to a maximum displacement position of the user input interface <NUM>. In various embodiments, the threshold displacement is about <NUM>% from a zero position of the user input interface <NUM> to a maximum displacement position of the user input interface <NUM>. In various embodiments, the threshold displacement is about <NUM>% from a zero position of the user input interface <NUM> to a maximum displacement position of the user input interface <NUM>. As used in the instant context, the term "about" refers to plus or minus <NUM>%. In various embodiments, the power supply condition is dependent on the emergency braking command. For example, if the emergency braking command indicates "no braking," the power supply condition generated and transmitted by the emergency park brake controller via the first electrical communication pathway <NUM> may indicate "power disconnection.

In various embodiments, the emergency park brake system <NUM> further includes one or more excitation monitors <NUM> that are coupled to the displacement sensor(s) <NUM>. The excitation monitor <NUM> is configured to provide electrical power to the displacement sensor <NUM> so that the displacement position can be provided to the emergency park brake controller <NUM>. The excitation level of the displacement sensor <NUM> may be, for example, in the form of a sine wave having a frequency of <NUM> Hertz and a voltage of <NUM> V (root mean squared voltage). In various embodiments, whether the electromechanical actuator <NUM> is in power receiving communication with the electrical power interface <NUM> is based on the detected valid excitation level of the displacement sensor <NUM> (e.g., the excitation monitor <NUM> checks the validity of the excitation level of the displacement sensor <NUM>). For example, if the excitation level provided from the excitation monitor <NUM> to the displacement sensor <NUM> is invalid (e.g., the displacement sensor is not detecting a displacement of the user input interface <NUM>), the power supply condition may indicate "power disconnection" and the selective electrical connection <NUM> between the electromechanical actuator <NUM> and the electrical power interface <NUM> may be electrically disconnected.

In various embodiments, the emergency park brake system <NUM> may include other detectors, sensors, or components that check various operating parameters to verify that a braking command is intended. For example, the emergency park brake system <NUM> may include multiple user input interfaces, such as an inboard and an outboard handle/lever. In various embodiments, the emergency park brake system <NUM> may include multiple displacement sensors. If one of the operating parameters does not meet a given threshold, the emergency park brake controller <NUM> may generate a power supply condition that indicates "power disconnection" or no power delivery to the electromechanical actuator <NUM>. If all the operating parameters meet the given thresholds, the emergency park brake controller <NUM> may generate a power supply condition that indicates "power connection" and thus the electromechanical actuator <NUM> may be electorally powered.

In various embodiments, and with reference to <FIG>, a method <NUM> of controlling an emergency park brake system is provided. The method <NUM> includes, in accordance with the claims, receiving an emergency braking input at step <NUM>. For example, an emergency park brake controller may receive the emergency braking input via a displacement sensor coupled to a user input interface (e.g., a brake handle). The method <NUM> does further include determining an emergency braking command at step <NUM>. In various embodiments, the emergency park brake controller generates the emergency braking command based on the emergency braking input. Still further, the method <NUM> includes determining, by the emergency park brake controller, a power supply condition at step <NUM>. Determining the power supply condition (step <NUM>) is based on the emergency braking command determined at step <NUM>. In accordance with the claims, the method <NUM> further includes actuating a hydraulic brake valve at step <NUM>. Step <NUM> is performed by the emergency park brake controller, via an electromechanical actuator, and based on the emergency braking command and the power supply condition determined in steps <NUM> and <NUM>, respectively.

In accordance with the claims, actuating the hydraulic brake valve to apply a braking force (step <NUM>) to wheels of the aircraft is performed in response to the power supply condition indicating a power connection. Step <NUM> includes transmitting, by the emergency park brake controller and via a first electrical communication pathway, the emergency braking command to the electromechanical actuator. Step <NUM> may also include transmitting, by the emergency park brake controller, based on the power supply condition, and via a second electrical communication pathway, electrical power from an electrical power interface to the electromechanical actuator.

Also, any reference to attached, fixed, connected, coupled or the like may include permanent (e.g., integral), removable, temporary, partial, full, and/or any other possible attachment option.

Claim 1:
An emergency park brake system of an aircraft, the emergency park brake system comprising:
an emergency park brake controller (<NUM>) configured to receive emergency braking input and configured to generate both an emergency braking command and a power supply condition in response to the emergency braking input;
an electrical power interface (<NUM>) configured to receive electrical power from a power source;
an electromechanical actuator (<NUM>);
a hydraulic brake valve (<NUM>), wherein the electromechanical actuator (<NUM>) is mechanically coupled to and configured to selectively actuate the hydraulic brake valve (<NUM>);
a first electrical communication pathway (<NUM>) extending between the emergency park brake controller (<NUM>) and the electrical power interface (<NUM>);
a second electrical communication pathway (<NUM>) extending between the emergency park brake controller (<NUM>) and the electromechanical actuator (<NUM>); and
a selective electrical connection (<NUM>) extending between the electrical power interface (<NUM>) and the electromechanical actuator (<NUM>), wherein the selective electrical connection is configured to be electrically connected to the electromechanical actuator (<NUM>)
in response to the power supply condition being satisfied;
wherein the electromechanical actuator (<NUM>) is configured to actuate the hydraulic brake valve (<NUM>) in response to an emergency braking command being received by the electromechanical actuator (<NUM>) from the emergency park brake controller (<NUM>) by the second electrical communication pathway (<NUM>) and in response to the selective electrical connection being electrically connected, wherein the selective electrical connection (<NUM>) is electrically connected in response to the power supply condition being received by the electrical power interface (<NUM>) from the emergency park brake controller (<NUM>) via the first electrical communication pathway (<NUM>) and the electrical power interface (<NUM>) providing power via the selective electrical connection (<NUM>) in response to the power supply condition indicating a power connection.