Patent Description:
The present disclosure relates to landing gear, and more particularly, to distributed landing gear system architectures for controlling actuation of landing gear subsystems.

Aircrafts generally include landing gear that supports the aircraft during taxi, take-off, and landing. After take-off, the landing gear may be translated to a "landing gear up" position, wherein the landing gear translates into a wheel well defined by, for example, a wing or a fuselage of the aircraft. Electrical landing gear systems may include electromechanical actuators (EMAs), or electric motors, configured to actuate various landing gear subsystems. Each EMA may have dedicated controller and motor drive unit configured to control and power the EMA. A controller and motor drive unit for each EMA tends to increase the size, weight, and number of parts associated with electrical landing gear systems. Systems for controlling landing gear are disclosed in <CIT>, <CIT> and <CIT>. Document <CIT> discloses according to its abstract a control circuit and a power circuit that are provided with an inverter module connected to a switching module with a connecting unit. The control circuit is connected to the switching module for controlling the switching module to sequentially connect electrical actuators to the inverter module. The control circuit is arranged to sequentially control the inverter module and the switching module. The control circuit comprises a monitoring module arranged to detect dysfunction of the device.

A system for controlling landing gear subsystems is provided as defined by claim <NUM>.

In various embodiments, the third electric motor may be configured to actuate a main landing gear bay door, and the fourth electric motor may be configured to actuate a main landing gear brake assembly.

In various embodiments, a first sensor may be operably coupled to at least one of the first electric motor or the second electric motor and in operable communication with the controller. A second sensor may be operably coupled to at least one of the third electric motor or the fourth electric motor and in operable communication with the controller. In various embodiments, the controller may be configured to output commands to the nose gear motor drive unit in response to signals output from the first sensor. The controller may be configured to output a second set of commands to the main gear motor drive unit in response to signals output from the second sensor.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration.

Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full, and/or any other possible attachment option. Surface cross hatching lines may be used throughout the figures to denote different parts but not necessarily to denote the same or different materials.

Throughout the present disclosure, like reference numbers denote like elements. Accordingly, elements with like element numbering may be shown in the figures, but may not be necessarily repeated herein for the sake of clarity.

Disclosed herein is a landing gear system architecture wherein resources are allocated and shared among various landing gear subsystems.

System program instructions and/or controller instructions may be loaded onto a tangible, non-transitory, computer-readable medium (also referred to herein as a tangible, non-transitory, memory) having instructions stored thereon that, in response to execution by a controller, cause the controller to perform various operations. 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.

With reference to <FIG>, an aircraft <NUM> is illustrated, in accordance with various embodiments. Aircraft <NUM> may include a fuselage <NUM> and wings <NUM>. Aircraft <NUM> may further include landing gear such as left landing gear <NUM>, right landing gear <NUM>, and nose landing gear <NUM>. Left landing gear <NUM>, right 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. Nose landing gear <NUM> is located under the nose of aircraft <NUM> and may not include a brake assembly. Nose landing gear <NUM> may be generally used for steering aircraft <NUM> during taxiing. Left landing gear <NUM> and right landing gear <NUM> may differ from nose landing gear <NUM>, in that left landing gear <NUM> and right landing gear <NUM> each generally include a brake assembly.

Left landing gear <NUM>, right landing gear <NUM>, and nose landing gear <NUM> may each include various shock strut assemblies with one or more wheels attached thereto. Left landing gear <NUM>, right landing gear <NUM>, and nose landing gear <NUM> may each be configured to translate between a landing gear down position, wherein the landing gear extend from wings <NUM> and/or from fuselage <NUM> to support aircraft <NUM>, and a landing gear up position, wherein the landing gear are located within wings <NUM> and/or fuselage <NUM> of aircraft <NUM>. For example, during taxiing, take-off, and landing, left landing gear <NUM>, right landing gear <NUM>, and nose landing gear <NUM> may be in the landing gear down position. After take-off, left landing gear <NUM>, right landing gear <NUM>, and nose landing gear <NUM> may be translated to the landing gear up position. Prior to landing, left landing gear <NUM>, right landing gear <NUM>, and nose landing gear <NUM> may be translated to the landing gear down position to support aircraft <NUM> during landing. In various embodiments, aircraft <NUM> may comprise any number of landing gears and each landing gear may comprise any number of wheels.

In accordance with various embodiments, aircraft <NUM> may include main landing gear bay doors <NUM> and nose landing gear bay doors <NUM>, which may be translated between an open position prior to landing gear retraction to a closed position after landing gear retraction. Bay doors <NUM>, <NUM> are also translated to the open position prior to landing gear extension.

With reference to <FIG> and <FIG>, aircraft <NUM> may include a landing gear system <NUM> configured to control operation of left landing gear <NUM> and right landing gear <NUM> (collectively referred to as "main landing gear") and operation of nose landing gear <NUM>. In accordance with various embodiments, landing gear system <NUM> comprises various subsystems configured to control different aspects of landing gear operation. For example, landing gear system <NUM> includes a nose landing gear bay door actuation subsystem <NUM> for controlling the opening and closing of nose landing gear bay doors <NUM>, a nose landing gear retraction-extension subsystem <NUM> for controlling retraction and extension of nose landing gear <NUM>, a nose landing gear steering subsystem <NUM> for controlling steering of nose landing gear <NUM>, and a nose landing gear emergency extension subsystem <NUM> for extending nose landing gear <NUM> should the nose landing gear retraction-extension subsystem <NUM> fail. Landing gear system <NUM> may further include a main gear bay door actuation subsystem <NUM> for controlling the opening and closing of main landing gear bay doors <NUM>, a main landing gear retraction-extension subsystem <NUM> for controlling retraction and extension of main landing gear <NUM>, <NUM>, a main landing gear brake control subsystem <NUM> for controlling the brake assemblies of main landing gear <NUM>, <NUM>, and a main landing gear emergency extension subsystem <NUM> for extending main landing gear <NUM>, <NUM> should the main landing gear retraction-extension subsystem <NUM> fail.

In accordance with various embodiments, the subsystems of landing gear system <NUM> generally do not operate simultaneously. TABLE <NUM> shows a typical operational scenario of aircraft <NUM>, where T1, T2, and T3 are the time durations for operation of landing gear subsystems <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and Power Demand is the relative power (e.g., high or low) associated with operation of the respective subsystem.

As illustrated in TABLE <NUM>, nose landing gear door actuation, nose landing gear retraction-extension, and nose landing gear steering control do not have overlapping operation time. Similarly, main landing gear door actuation, main landing gear retraction-extension, and main landing gear brake control have non-simultaneous (i.e., nonconcurrent) operation. Thus, it may be desirable to design a system architecture for landing gear system <NUM>, wherein resources are shared among the subsystems, thereby reducing system costs and weight. In various embodiments, the landing gear subsystems <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, which have a relatively low power demand, may be powered electrically and main landing gear retraction-extension subsystem <NUM>, which has a relatively high power demand, may be powered hydraulically. Thus, in various embodiments, landing gear system <NUM> may be a hybrid system that employs electromechanical actuators, or electric motors, for actuation of landing gear subsystems <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, and hydraulic actuators for actuation of main landing gear retraction-extension subsystem <NUM>. In various embodiments, landing gear system <NUM> may employ electromechanical actuators, or electric motors, for actuation of landing gear subsystems <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, and for actuation of main landing gear retraction-extension subsystem <NUM>.

With reference to <FIG>, and continuing reference to <FIG> and <FIG>, a system <NUM> for powering and controlling various landing gear subsystems is illustrated. System <NUM> includes a nose gear door actuation, gear retraction-extension, and emergency extension motor drive unit <NUM> (referred to herein as nose gear motor drive unit <NUM>) configured to drive a nose gear door motor <NUM>, a nose gear retraction-extension motor <NUM>, and optionally an emergency nose gear extension motor <NUM>. In various embodiments, nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and emergency nose gear extension motor <NUM> may each comprises an electric motor (e.g., a permanent magnet synchronous motor (PMSM), a brushless direct current (BLDC) motor, or other suitable electric motor). Nose gear door motor <NUM> may translate nose landing gear bay doors <NUM> between the open and closed position. Nose gear retraction-extension motor <NUM> may translate nose landing gear <NUM> between the landing gear down and landing gear up positions. Emergency nose gear extension motor <NUM> may translate nose landing gear <NUM> to the landing gear down position.

During operation of aircraft <NUM>, nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and emergency nose gear extension motor <NUM> may be operated at different times (i.e., not simultaneously). In accordance with various embodiments, a single nose gear motor drive unit <NUM> may be employed to operate (i.e., drive) nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and emergency nose gear extension motor <NUM>. For example, if nose gear motor drive unit <NUM> is driving nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and emergency nose gear extension motor <NUM> may be dormant (i.e., powered off).

System <NUM> includes a steering motor drive unit <NUM> configured to drive steering control motor <NUM>. In various embodiments, steering control motor <NUM> comprises an electric motor (e.g., a PMSM, a BLDC motor, or other suitable electric motor). Steering control motor <NUM> may control the steering system used to steer nose landing gear <NUM> (e.g., steering control motor <NUM> may pivot, or turn, nose landing gear <NUM> to the left or to the right). During operation of aircraft <NUM>, steering control motor <NUM> may be operated at a different time from (i.e., non-simultaneously or nonconcurrent with) nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and emergency nose gear extension motor <NUM>.

System <NUM> includes a main landing gear door actuation and brake control motor drive unit <NUM> (referred to herein as main gear motor drive unit <NUM>) configured to drive one or more main gear door motor(s) <NUM> and one or more brake control motor(s) <NUM>. Main gear door motors <NUM> and brake control motors <NUM> comprise electric motors (e.g. PMSMs, BLDC motors, or other suitable electric motor). Main gear door motors <NUM> translate main landing gear bay doors <NUM> between the open and closed positions. Brake control motors <NUM> control the braking of main landing gear <NUM>, <NUM>. For example, brake control motors <NUM> may control the braking pressure applied by the brake assemblies of main landing gear <NUM>, <NUM>.

During operation of aircraft <NUM>, main gear door motors <NUM> and brake control motors <NUM> may be operated at different times (i.e., non-simultaneously or nonconcurrent with one another). In accordance with various embodiments, a single main gear motor drive unit <NUM> may be employed to operate (i.e., drive) main gear door motors <NUM> and brake control motors <NUM>. For example, if main gear motor drive unit <NUM> is driving the main gear door motors <NUM>, the brake control motors <NUM> may be dormant (i.e., powered off).

System <NUM> further includes a controller <NUM>. Controller <NUM> is operably coupled to and in communication with nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and main gear motor drive unit <NUM>. Controller <NUM> may include operating instructions and/or power sequence logic configured to cause nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and/or main gear motor drive unit <NUM> to power motors <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> in a particular order and/or during certain operating conditions.

Controller <NUM> may include and communicate with one or more processors and one or more tangible, non-transitory storage medium(s), or memories, <NUM> and is capable of implementing landing gear logic. The 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 (PLD), discrete gate or transistor logic, discrete hardware components, or a combination thereof. System program instructions and/or processor instructions may be loaded onto tangible, non-transitory computer-readable storage medium <NUM>. The system program instructions and/or processor instructions may, in response to execution by controller <NUM>, cause controller <NUM> to perform various operations. In particular, and as described in further detail below, the instructions may allow controller <NUM> to make operating and/or power sequence decisions relative the landing gear subsystems. For example, controller <NUM> may be configured to determine which of motors <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> should be receiving power and/or operating at a particular time.

In various embodiments, system <NUM> may include one or more door sensors <NUM> operationally coupled to nose gear door motor <NUM> and/or to nose landing gear bay doors <NUM>. The output of door sensors <NUM> may correlate to operating conditions of nose gear door motor <NUM> (e.g., velocity, position, etc.). The output of door sensors <NUM> may also provide information related to the position of nose landing gear bay doors <NUM>. The output of door sensors <NUM> may be received by nose gear motor drive unit <NUM>. The output of door sensors <NUM> may be sent from nose gear motor drive unit <NUM> to controller <NUM>. Controller <NUM> may make decisions related to the operation of nose gear door motor <NUM> based on the signals output from door sensors <NUM>. Controller <NUM> may also make decisions related to the operation of nose gear retraction-extension motor <NUM>, emergency nose gear extension motor <NUM> and/or steering control motor <NUM> based on the signals output from door sensors <NUM>. In various embodiments, controller <NUM> may output commands to nose gear motor drive unit <NUM> configured to cause nose gear motor drive unit <NUM> to power (or excite) door sensors <NUM>, when nose gear door motor <NUM> is in operation. In various embodiments, door sensors <NUM> may also operate (i.e., receive power and provide output) when nose gear door motor <NUM> is turned off.

System <NUM> may include one or more retraction sensors <NUM> operationally coupled to nose gear retraction-extension motor <NUM> and/or to components of nose landing gear <NUM> (e.g., to a shock struct of nose landing gear <NUM>). The output of retraction sensors <NUM> may correlate to one or more operating conditions of nose gear retraction-extension motor <NUM> (e.g., velocity, position, etc.). The output of retraction sensors <NUM> may also provide information related to the position of nose landing gear <NUM> (e.g., extended, retracted, etc.). The output of retraction sensors <NUM> may be received by nose gear motor drive unit <NUM>. The output of retraction sensors <NUM> may be sent from nose gear motor drive unit <NUM> to controller <NUM>. Controller <NUM> may make decisions related to the operation of nose gear retraction-extension motor <NUM> based on the signals output from retraction sensors <NUM>. Controller <NUM> may also make decisions related to the operation of nose gear door motor <NUM>, emergency nose gear extension motor <NUM> and/or steering control motor <NUM> based on the signals output from retraction sensors <NUM>. In various embodiments, controller <NUM> may output commands to nose gear motor drive unit <NUM> configured to cause nose gear motor drive unit <NUM> to power (or excite) retraction sensors <NUM>, when nose gear retraction-extension motor <NUM> is in operation. In various embodiments, retraction sensors <NUM> may also operate (i.e., receive power and provide output) when nose gear retraction-extension motor <NUM> is turned off.

System <NUM> may include one or more emergency extension sensors <NUM> operationally coupled to emergency nose gear extension motor <NUM> and/or to components of nose landing gear <NUM> (e.g., to a shock struct of nose landing gear <NUM>). The output of emergency extension sensors <NUM> may correlate to operating conditions of emergency nose gear extension motor <NUM> (e.g., velocity, position, etc.). The output of emergency extension sensors <NUM> may also provide information related to the position of nose landing gear <NUM> (e.g., extended, retracted, etc.). The output of emergency extension sensors <NUM> may be received by nose gear motor drive unit <NUM>. The output of emergency extension sensors <NUM> may be sent from nose gear motor drive unit <NUM> to controller <NUM>. Controller <NUM> may make decisions related to the operation of emergency nose gear extension motor <NUM> based on the signals output from emergency extension sensors <NUM>. Controller <NUM> may also make decision related to the operation of nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and/or steering control motor <NUM> based on the signals output from emergency extension sensors <NUM>. In various embodiments, controller <NUM> may output commands to nose gear motor drive unit <NUM> configured to cause nose gear motor drive unit <NUM> to power (or excite) emergency extension sensors <NUM>, when emergency nose gear extension motor <NUM> is in operation. In various embodiments, emergency extension sensors <NUM> may also operate (i.e., receive power and provide output) when emergency nose gear extension motor <NUM> is turned off.

System <NUM> employs one or more steering sensors <NUM> operationally coupled to steering control motor <NUM> and/or to components of nose landing gear <NUM>. The output from steering sensors <NUM> may correlate to one or more operating conditions of steering control motor <NUM> (e.g., velocity, position, etc.). The output of steering sensors <NUM> may also provide information related to the positioning or orientation (left, right, etc.) of nose landing gear <NUM>. The output of steering sensors <NUM> may be received by steering motor drive unit <NUM>. The output from steering sensors <NUM> is sent from steering motor drive unit <NUM> to controller <NUM>. Controller <NUM> may make decisions related to the operation of steering control motor <NUM> based on the signals output from steering sensors <NUM>. Controller <NUM> may also make decisions related to the operation of nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and/or emergency nose gear extension motor <NUM> based on the signals output from steering sensors <NUM>. In various embodiments, controller <NUM> may output commands to steering motor drive unit <NUM> configured to cause steering motor drive unit <NUM> to power (or excite) steering sensors <NUM>, when steering control motor <NUM> is in operation. In various embodiments, steering sensors <NUM> may also operate (i.e., receive power and provide output), when steering control motor <NUM> is turned off.

System <NUM> may include one or more main door sensors <NUM> operationally coupled to main gear door motors <NUM> and/or to main landing gear bay doors <NUM>. The output of main door sensors <NUM> may correlate to one or more operating conditions of main gear door motors <NUM> (e.g., velocity, position, etc.). The output of main door sensors <NUM> may also provide information related to the position of main landing gear bay doors <NUM>. The output of main door sensors <NUM> may be received by main gear motor drive unit <NUM>. The output of main door sensors <NUM> may be sent from main gear motor drive unit <NUM> to controller <NUM>. Controller <NUM> may make decisions related to the operation of main gear door motors <NUM> based on the signals output from main door sensors <NUM>. In various embodiment, controller <NUM> may also make decisions related to the operation of brake control motors <NUM> based on the output from main door sensors <NUM>. In various embodiments, controller <NUM> may output commands to main gear motor drive unit <NUM> configured to cause main gear motor drive unit <NUM> to power (or excite) main door sensors <NUM>, when main gear door motors <NUM> is in operation. In various embodiments, main door sensors <NUM> may also operate (i.e., receive power and provide output), when main gear door motors <NUM> are turned off.

System <NUM> may include one or more brake sensors <NUM> operationally coupled to the brake control motors <NUM> and/or to the braking assemblies or other components of the main landing gear <NUM>, <NUM>. The brake sensors <NUM> may include sensor that output data correlating to one or more operating conditions of the brake control motors <NUM> (e.g., velocity, position, etc.). Brake sensors <NUM> may also include sensor configured to out information related to the position or pressure being applied by the brake assemblies of the main landing gear <NUM>, <NUM>. Brake sensors <NUM> may also include sensors that provide information related to whether aircraft <NUM> is on the ground or in the air (e.g., brake sensors <NUM> may include one or more weight on wheels sensors). In various embodiments, the brake assemblies of main landing gear <NUM>, <NUM> may be configured to not apply braking pressure when the aircraft is in the air (e.g., brake command signals from the pilot or from an autobraking system may be disabled when the aircraft is in the air). In this regard, the brake assemblies may be configured to apply braking pressure when, based on the output from one or more brake sensors <NUM>, aircraft <NUM> is determined to be on the ground. In various embodiments, the output of brake sensors <NUM> may be received by main gear motor drive unit <NUM>. The output of brake sensors <NUM> may be sent from main gear motor drive unit <NUM> to controller <NUM>. Controller <NUM> may make decisions related to the operation of brake control motors <NUM> based on the signals output from brake sensors <NUM>. Controller <NUM> may also make decisions related to the operation of main gear door motors <NUM> based on the signals output from brake sensors <NUM>. In various embodiments, controller <NUM> may output commands to main gear motor drive unit <NUM> configured to cause main gear motor drive unit <NUM> to power (or excite) brake sensors <NUM>, when brake control motors <NUM> are in operation. In various embodiments, brake sensors <NUM> may also operate (i.e., receive power and provide output), when brake control motors <NUM> are turned off.

In accordance with various embodiments, controller <NUM> is configured to make operating decisions for controlling the various landing gear subsystems and motors <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Controller <NUM> may determine the sequence in which motors <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are powered in response to receiving pilot commands <NUM> from the cockpit (e.g., from the pilot, the co-pilot, or higher level flight control systems) of aircraft <NUM>. Stated differently, controller <NUM> may determine a nose gear power sequence for powering motors <NUM>, <NUM>, <NUM>, and <NUM> and a main landing gear power sequence for powering main gear door motors <NUM> and brake control motors <NUM> in response to receiving pilot command <NUM>. In various embodiments, controller <NUM> may receive pilot command <NUM> in response to, for example, the pilot translating a landing gear lever <NUM> between a landing up lever position and a landing gear down lever position. Controller <NUM> may determine a sequence of operation for motors <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> in response to pilot command <NUM>. Stated differently, controller <NUM> may output a series of power commands to nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and/or main gear motor drive unit <NUM>, in response to the landing gear lever <NUM> being translated from the landing up lever position to the landing down lever position or from the landing gear down lever position to the landing gear up lever position.

For example, with combined reference to <FIG> and <FIG>, in response to receiving a pilot command <NUM> indicating landing gear lever <NUM> was translated from the landing gear up lever position to the landing gear down lever position, controller <NUM> may determine a nose gear power sequence configured to first open the nose landing gear bay doors <NUM>, then extend the nose landing gear <NUM>, and then power the steering motor. In this regard, controller <NUM> may be configured to, in response to receiving pilot command <NUM>, output a command (or series of commands) to nose gear motor drive unit <NUM>. The command may be configured to cause nose gear motor drive unit <NUM> to power nose gear door motor <NUM>, thereby causing nose landing gear bay doors <NUM> to open. In response to controller <NUM> determining the nose landing gear bay doors <NUM> are open (e.g., in response signals received from door sensors <NUM>), controller <NUM> may send a command (or series of commands) to nose gear motor drive unit <NUM> configured to cause nose gear motor drive unit <NUM> to stop powering (i.e., power-off) nose gear door motor <NUM> and to start powering (i.e., power-on) nose gear retraction-extension motor <NUM>, thereby causing nose landing gear <NUM> to extend. If controller <NUM> determines nose landing gear <NUM> has not extended, for example, based on output from retraction sensors <NUM>, controller <NUM> may send a command (or series of commands) configured to cause nose gear motor drive unit <NUM> to stop powering (i.e., power-off) nose gear retraction-extension motor <NUM> and to start powering (i.e., power-on), emergency nose gear extension motor <NUM>, thereby causing nose landing gear <NUM> to extend. In response to controller <NUM> determining nose landing gear <NUM> is the landing gear down position (e.g., in response to signals from retraction sensors <NUM> and/or emergency extension sensors <NUM>), controller <NUM> may send a command (or series of commands) to steering motor drive unit <NUM> and a command (or series of commands) to nose gear motor drive unit <NUM>. The commands may be configured to cause nose gear motor drive unit <NUM> to stop powering (i.e., power-off) nose gear retraction-extension motor <NUM> and to start powering (i.e., power-on) steering control motor <NUM>.

In accordance with various embodiments, in response to receiving the pilot command <NUM> indicating landing gear lever <NUM> was translated from the landing gear up lever position to the landing gear down lever position, controller <NUM> may also determine a main landing gear power sequence configured to first power the main gear door motors <NUM> and then power the brake control motors <NUM>. In this regard, controller <NUM> may be configured to, in response to receiving pilot command <NUM>, output a first command (or series of first commands) to main gear motor drive unit <NUM> configured to cause main gear motor drive unit <NUM> to power the main gear door motors <NUM>, thereby causing main landing gear bay doors <NUM> to open. In response to controller <NUM> determining the nose landing gear bay doors <NUM> are open (e.g., in response signals received from main door sensors <NUM>), controller <NUM> may send a command (or series of second commands) to main gear motor drive unit <NUM> configured to cause main gear motor drive unit <NUM> to stop powering (i.e., power-off) main gear door motors <NUM> and to start powering (i.e., power-on) brake control motors <NUM>.

With continued referent to <FIG>, in accordance with various embodiments, system <NUM> includes an alternating current to direct current (AC/DC) converter <NUM>. AC/DC converter <NUM> is configured to provide power (e.g., DC current) to each of nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and main gear motor drive unit <NUM>. In this regard, AC/DC converter <NUM> is electrically coupled to an AC power supply <NUM> and to nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and main gear motor drive unit <NUM>. AC/DC converter <NUM> is configured convert the AC received from AC power supply <NUM> to DC, which is provided to nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and/or main gear motor drive unit <NUM>.

The power provided by AC/DC converter <NUM> is configured to power nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, emergency nose gear extension motor <NUM>, steering control motor <NUM>, main gear door motors <NUM>, and/or brake control motors <NUM>. Power may be provided by a common, or single, AC/DC converter <NUM> as drive nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and emergency nose gear extension motor <NUM> do not operate simultaneously and because main gear door motors <NUM> do not operate simultaneously with brake control motors <NUM>. In this regard, at a given time, the current provided by AC/DC converter <NUM> may be supplied to either nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, or emergency nose gear extension motor <NUM>; to steering control motor <NUM>; and to either main gear door motors <NUM> or brake control motors <NUM>.

In response to receiving pilot command <NUM> (e.g., a landing gear lever up or landing gear lever down signal), controller <NUM> may determine the sequence in which power from AC/DC converter <NUM> is provided to nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, emergency nose gear extension motor <NUM>, and steering control motor <NUM> and the sequence in which power from AC/DC converter <NUM> is provided to main gear door motors <NUM> and brake control motors <NUM>. In this regard, controller <NUM> determines and controls which nose landing gear motors (e.g., nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, emergency nose gear extension motor <NUM>, or steering control motor <NUM>) and which main landing gear motors (e.g., main gear door motors <NUM> or brake control motors <NUM>) should be powered-on and which should be powered-off. Controller <NUM> may send commands to nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and main gear motor drive unit <NUM> based on the determined sequence. The commands are configured to cause to nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, main gear motor drive unit <NUM> to power the motor(s) in the sequence determined by controller <NUM>.

System <NUM> employs a centralized AC/DC converter <NUM>, rather than individual AC/DC converter for each drive unit. The power provided by AC/DC converter <NUM> may be less than the sum of the peak of the power associated with driving each of motors <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, as motors <NUM>, <NUM>, and <NUM>, for example, do not operate simultaneously. In this regard, centralized AC/DC converter <NUM> may decrease the cost and weight of system <NUM>, as compared to systems wherein each motor has a dedicated motor drive unit, and each motor drive unit has a dedicated AC/DC converter. In various embodiments, each of motor drive units <NUM>, <NUM>, <NUM> may include a DC link capacitor, rather than a complete AC/DC converter, which tends to reduce the size and weight of the motor drive units.

System <NUM> employs a braking resistor <NUM> electrically coupled to nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and main gear motor drive unit <NUM>. Braking resistor <NUM> is configured to dissipate the regeneration energy of the motor drive units <NUM>, <NUM>, <NUM>. System <NUM> employing a centralized braking resistor circuit to dissipate the regeneration energy from any of motor drive units <NUM>, <NUM>, <NUM>, tends to decrease a weight and size of motor drive units <NUM>, <NUM>, <NUM>, as compared to motor drive units that include their own dedicated braking resistor within the motor drive unit. In various embodiments, system <NUM> including braking resistor <NUM> may allow liquid cooling to be employed to dissipate heat from braking resistor <NUM>, as single, centralized a braking resistor circuit simplifies the routing of the liquid coolant, as compared to systems wherein liquid cooling is provided to individual brake resistor units located in each motor drive unit.

With reference to <FIG>, addition details of controller <NUM> and nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and main gear motor drive unit <NUM> are illustrated. In various embodiments, controller <NUM> may be a multi-core controller. Controller <NUM> may have a core dedicated each of the motor drive units <NUM>, <NUM>, <NUM>. In various embodiments, controller <NUM> may include a first core <NUM> having instructions stored thereon related to operation of nose gear motor drive unit <NUM>. Controller <NUM> may include a second core <NUM> having instructions stored thereon related to operation of steering motor drive unit <NUM>. Controller <NUM> may include a third core <NUM> having instruction related to operation of main gear motor drive unit <NUM>. Controller <NUM> may further include a fourth core <NUM> having instruction stored thereon related to management of the other cores of controller <NUM>. Fourth core <NUM> may be in communication with first core <NUM>, second core <NUM>, and third core <NUM>. Cores <NUM>, <NUM>, <NUM>, <NUM> may each include one or more processors and one or more tangible, non-transitory storage medium(s). The processor can be a general purpose processor, a DSP, an ASIC, a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or a combination thereof.

First core <NUM>, second core <NUM>, and third core <NUM> are in communication with nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and main gear motor drive unit <NUM>, respectively. First core <NUM>, second core <NUM>, and third core <NUM> may send commands to nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and main gear motor drive unit <NUM>, respectively, via a communication module <NUM> of controller <NUM>. In various embodiments, nose gear motor drive unit <NUM> includes a communication module <NUM>, steering motor drive unit <NUM> includes a communication module <NUM>, and main gear motor drive unit <NUM> includes a communication module <NUM>. Communication modules <NUM>, <NUM>, <NUM> are each operably coupled to communication module <NUM> of controller <NUM> via links <NUM>. Links <NUM> may represent a wired or a wireless connection. In this regard, communication modules <NUM>, <NUM>, <NUM> may communicated with communication module <NUM> wireless or in various embodiments, via wired connection. In various embodiments, a digital cable may electrically couple communication modules <NUM>, <NUM>, <NUM> to communication module <NUM>.

Controller <NUM> may receive information related to operation of nose gear motor drive unit <NUM>, steering motor drive unit <NUM>, and main gear motor drive unit <NUM> via communication module <NUM> and communication modules <NUM>, <NUM>, <NUM>. The information received by controller <NUM> may be related to operation of nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, emergency nose gear extension motor <NUM>, steering control motor <NUM>, main gear door motors <NUM>, and brake control motors <NUM>.

With continued reference to <FIG>, additional details of motor drive units <NUM>, <NUM>, <NUM> are illustrated. In various embodiments, nose gear motor drive unit <NUM> may include communication module <NUM>, which is configured to communicate with controller <NUM>. Nose gear motor drive unit <NUM> may include a device <NUM> configured to control nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and/or emergency nose gear extension motor <NUM>. Device <NUM> may be a FPGA or other PLD. Device <NUM> may be configured to receive commands from controller <NUM> and generate pulse width modulation (PWM) signals corresponding to the commands from controller <NUM>. The PWM signals may be provided to and may control nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and/or emergency nose gear extension motor <NUM>. Device <NUM> may include an analog interface <NUM> for receiving and outputting signals to sensors <NUM>, <NUM>, <NUM>. Nose gear motor drive unit <NUM> further includes a gate drive circuit <NUM> configured to receive output from device <NUM> and, in response to the signals from device <NUM>, output to signals to an inverter <NUM> of nose gear motor drive unit <NUM>. In various embodiments, inverter <NUM> may be a three phase inverter. In various embodiments, nose gear motor drive unit <NUM> may include a DC/DC converter <NUM> for powering the components of the nose gear motor drive unit <NUM> (e.g., gate drive circuit <NUM>, communication module <NUM>, etc.). In various embodiments, nose gear motor drive unit <NUM> may include a DC BUS <NUM> operationally coupled to inverter <NUM>.

In various embodiments, steering motor drive unit <NUM> may include communication module <NUM>, which is configured to communicate with controller <NUM>. Steering motor drive unit <NUM> may include a device <NUM> configured to control the steering control motor <NUM>. Device <NUM> may be FPGA or other PLD. Device <NUM> may be configured to receive commands from controller <NUM> and generate PWM signals corresponding to the commands from controller <NUM>. The PWM signal may be provided to and may control the steering control motor <NUM>. Device <NUM> may include an analog interface <NUM> for receiving signals from and outputting signals to steering sensors <NUM>. Steering motor drive unit <NUM> further includes a gate drive circuit <NUM> configured to receive output from device <NUM> and, in response to the signals from device <NUM>, output to signals to an inverter <NUM> of steering motor drive unit <NUM>. In various embodiments, inverter <NUM> may be a three phase inverter. In various embodiments, steering motor drive unit <NUM> may include a DC/DC converter <NUM> for powering the components of the steering motor drive unit <NUM> (e.g., gate drive circuit <NUM>, communication module <NUM>, etc.). In various embodiments, steering motor drive unit <NUM> may include a DC BUS <NUM> operationally coupled to inverter <NUM>.

In various embodiments, main gear motor drive unit <NUM> may include communication module <NUM>, which is configured to communicate with controller <NUM>. Main gear motor drive unit <NUM> may include a device <NUM> configured to control the main gear door motors <NUM> and brake control motors <NUM>. Device <NUM> may be FPGA or other PLD. Device <NUM> may be configured to receive commands from controller <NUM> and generate PWM signals corresponding to the commands from controller <NUM>. The PWM signal may be provided to and may control the main gear door motors <NUM> and brake control motors <NUM>. Device <NUM> may include an analog interface <NUM> for receiving and outputting signals to sensors <NUM>, <NUM>. Main gear motor drive unit <NUM> further includes a gate drive circuit <NUM> configured to receive output from device <NUM> and, in response to the signals from device <NUM>, output to signals to an inverter <NUM> of main gear motor drive unit <NUM>. In various embodiments, inverter <NUM> may be a three phase inverter. In various embodiments, main gear motor drive unit <NUM> may include a DC/DC converter <NUM> for powering the components of the main gear motor drive unit <NUM> (e.g., gate drive circuit <NUM>, communication module <NUM>, etc.). In various embodiments, main gear motor drive unit <NUM> may include a DC BUS <NUM> operationally coupled to inverter <NUM>.

System <NUM> including AC/DC converter <NUM> is configured to generate high voltage direct current (HVDC) rail for use by each of motor drive units <NUM>, <NUM>, <NUM>. This may allow for the elimination of dedicated rectifier units in each of the motor drive units. The power level of AC/DC converter <NUM> may be optimized to meet the power demands of each of motor drive units <NUM>, <NUM>, <NUM>. Using AC/DC converter <NUM> to power each of motor drive units <NUM>, <NUM>, <NUM> decreases the cost, weight, and space occupied by the system. Cooling a centralized braking resistor <NUM>, as opposed to individual braking resistors in each of motor drive units <NUM>, <NUM>, <NUM>, allows the size of the motor drive units to be reduced, as individual heat sink may be eliminated from the motor drive unit. System <NUM> employing a single, common controller <NUM> for controlling multiple drive units and motors tends to reduce the component count, cost, weight and space occupied by system <NUM>.

With reference to <FIG>, a system <NUM> for controlling landing gear subsystems is illustrated. System <NUM> is similar to system <NUM> in <FIG> and <FIG>, but includes various redundancies. Elements with like element numbering, as depicted in <FIG>, are intended to be the same and will not necessarily be repeated for the sake of clarity.

In accordance with various embodiments, system <NUM> includes controller <NUM>, motor drive units <NUM>, <NUM>, <NUM>, and motors <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, as described with reference to system <NUM> in <FIG> and <FIG>. System <NUM> further includes AC/DC converter <NUM>, AC power supply <NUM>, and braking resistor <NUM>. In accordance with various embodiments, system <NUM> may further include a secondary controller <NUM>, similar to controller <NUM>, and having one or more processors and one or more tangible, non-transitory storage medium(s), or memories, <NUM>. In various embodiments, secondary controller <NUM> may be in communication with and/or may provide commands to motor drive units <NUM>, <NUM>, <NUM>. Secondary controller <NUM> may be identical, or nearly identical, to controller <NUM>, and may provide redundancy should controller <NUM> fail.

In accordance with various embodiments, system <NUM> may further include a secondary nose gear door actuation, gear retraction-extension, and emergency extension motor drive unit <NUM> (referred to herein as secondary nose gear motor drive unit <NUM>). Secondary nose gear motor drive unit <NUM> is operationally coupled to secondary controller <NUM>. Secondary nose gear motor drive unit <NUM> is configured to drive nose gear door motor <NUM>, nose gear retraction-extension motor <NUM>, and emergency nose gear extension motor <NUM> in response to commands from secondary controller <NUM>. In various embodiments, secondary nose gear motor drive unit <NUM> may be in communication with and/or receive commands from both controller <NUM> and secondary controller <NUM>. Secondary nose gear motor drive unit <NUM> may be identical, or nearly identical, to nose gear motor drive unit <NUM> and may provide redundancy should nose gear motor drive unit <NUM> fail.

System <NUM> may further include a secondary steering motor drive unit <NUM> operationally coupled to secondary controller <NUM>. Secondary steering motor drive unit <NUM> is configured to drive steering control motor <NUM> in response to commands from secondary controller <NUM>. In various embodiments, secondary steering motor drive unit <NUM> may be in communication with and/or receive commands from both controller <NUM> and secondary controller <NUM>. Secondary steering motor drive unit <NUM> may be identical, or nearly identical, to steering motor drive unit <NUM> and may provide redundancy should steering motor drive unit <NUM> fail.

System <NUM> may further include a secondary main gear motor drive unit <NUM> operationally coupled to secondary controller <NUM>. Secondary main gear motor drive unit <NUM> is configured to drive the main gear door motors <NUM> and the brake control motors <NUM> in response to commands from secondary controller <NUM>. In various embodiments, secondary main gear motor drive unit <NUM> may be in communication with and/or receive commands from both controller <NUM> and secondary controller <NUM>. Secondary main gear motor drive unit <NUM> may be identical, or nearly identical, to main gear motor drive unit <NUM> and may provide redundancy should main gear motor drive unit <NUM> fail.

In accordance with various embodiments, system <NUM> includes a secondary AC/DC converter <NUM> configured to provide power (e.g., DC current) to each of secondary motor drive units <NUM>, <NUM>, <NUM>. Secondary AC/DC converter <NUM> may be electrically coupled to a secondary AC power supply <NUM>. In various embodiments, secondary AC/DC converter <NUM> may be electrically coupled to both motor drive units <NUM>, <NUM>, <NUM> and secondary motor drive units <NUM>, <NUM>, <NUM>. Secondary AC/DC converter <NUM> may be identical, or nearly identical, to AC/DC converter <NUM> and may provide redundancy should AC/DC converter <NUM> fail.

In accordance with various embodiments, system <NUM> may also include a secondary braking resistor <NUM> electrically coupled to secondary motor drive units <NUM>, <NUM>, <NUM>. Secondary braking resistor <NUM> may dissipate the regeneration energy of the secondary motor drive units <NUM>, <NUM>, <NUM>. In various embodiments, secondary braking resistor <NUM> may be electrically coupled to both motor drive units <NUM>, <NUM>, <NUM> and secondary motor drive units <NUM>, <NUM>, <NUM>. Secondary braking resistor 374may be identical, or nearly identical, to braking resistor <NUM> and may provide redundancy should braking resistor <NUM> fail.

In various embodiments, and with reference to <FIG>, a system <NUM> for controlling landing gear subsystems is illustrated. System <NUM> may be similar to system <NUM> in <FIG> and <FIG>. Elements with like element numbering, as depicted in <FIG>, are intended to be the same and will not necessarily be repeated for the sake of clarity.

In accordance with various embodiments, main gear motor drive unit <NUM> of system <NUM> may be configured to drive the main gear door motors <NUM>, the brake control motors <NUM>, and one or more main gear retraction-extension motor(s) <NUM>. In various embodiments, main gear retraction-extension motors <NUM> may comprise electric motors (e.g., PMSMs, BLDC motors, or any other suitable electric motor). Main gear retraction-extension motors <NUM> may be configured to drive one or more hydraulic pumps that supply hydraulic pressure and fluid flow to hydraulic actuators configured to control retraction and extension of main landing gear <NUM>, <NUM>. Stated differently, retraction and extension of main landing gear <NUM>, <NUM> may be controlled by electro hydrostatic actuators, and main gear motor drive unit <NUM> may provide power (i.e., current) to the electro hydrostatic actuators. In various embodiments, main landing gear <NUM>, <NUM> may be translated between the landing gear up and landing gear down positions electrically (e.g., via EMAs). In this regard, main gear retraction-extension motors <NUM> may translate main landing gear <NUM>, <NUM> between the landing gear down and landing gear up positions.

During operation of aircraft <NUM>, main gear door motors <NUM>, brake control motors <NUM>, and main gear retraction-extension motors <NUM> may be operated at different times (i.e., not simultaneously). In accordance with various embodiments, a single main gear motor drive unit <NUM> may be employed to operate (i.e., drive) main gear door motors <NUM>, brake control motors <NUM>, and main gear retraction-extension motors <NUM>. For example, if main gear motor drive unit <NUM> is driving main gear retraction-extension motors <NUM>, main gear door motors <NUM> and brake control motors <NUM> may be dormant (i.e., powered off).

System <NUM> may include one or more main gear retraction sensors <NUM> may include one or more main gear retraction sensors <NUM> operationally coupled to main gear retraction-extension motors <NUM> and/or to components of main landing gear <NUM>, <NUM> (e.g., to shock structs of left landing gear <NUM> and right landing gear <NUM>). The output of main retraction sensors <NUM> may correlate to one or more operating conditions of main gear retraction-extension motors <NUM> (e.g., velocity, position, etc.). The output of main retraction sensors <NUM> may also provide information related to the position of main landing gear <NUM>, <NUM> (e.g., extended, retracted, etc.). The output of main retraction sensors <NUM> may be received by main gear motor drive unit <NUM>. The output of main retraction sensors <NUM> may be sent from main gear motor drive unit <NUM> to controller <NUM>. Controller <NUM> may make decisions related to the operation of main gear retraction-extension motors <NUM> based on the signals output from main retraction sensors <NUM>. Controller <NUM> may also make decisions related to the operation of main gear door motors <NUM> and/or brake control motors <NUM> based on the signals output from main gear retraction sensors <NUM>. In various embodiments, main gear motor drive unit <NUM> may also drive one or emergency main gear extension motors and may make decisions related to the operation of the emergency main gear extension motors based on the signals output from main gear retraction sensors <NUM>, similar to nose gear motor drive unit <NUM> and emergency nose gear extension motor <NUM>. In various embodiments, controller <NUM> may output commands to main gear motor drive unit <NUM> configured to cause main gear motor drive unit <NUM> to power (or excite) main retraction sensors <NUM>, when main gear retraction-extension motors <NUM> are in operation. In various embodiments, main retraction sensors <NUM> may also operate (i.e., receive power and provide output) when main gear retraction-extension motors <NUM> are turned off.

Claim 1:
A system for controlling landing gear subsystems, comprising:
a controller (<NUM>);
a nose gear motor drive unit (<NUM>) in operable communication with the controller;
a first electric motor (<NUM>) in operable communication with the nose gear motor drive unit;
a second electric motor (<NUM>) in operable communication with the nose gear motor drive unit, wherein the nose gear motor drive unit is configured to drive one of the first electric motor or the second electric motor at a time;
a main gear motor drive unit (<NUM>) in operable communication with the controller;
a third electric motor (<NUM>) in operable communication with the main gear motor drive unit;
a fourth electric motor (<NUM>) in operable communication with the main gear motor drive unit, wherein the main gear motor drive unit is configured to drive one of the third electric motor or the fourth electric motor at a time;
a braking resistor (<NUM>) electrically coupled to the nose gear motor drive unit and the main gear motor drive unit, the braking resistor being configured to dissipate regeneration energy from the nose gear motor drive unit and the main gear motor drive unit;
an alternating current direct current converter (<NUM>) electrically coupled to the nose gear motor drive unit and the main gear motor drive unit, the alternating current direct current converter configured to provide power to at least the nose gear motor drive unit and the main gear motor drive unit;
a steering motor drive unit (<NUM>) in operable communication with the controller, the steering motor drive unit configured to receive output of steering sensors (<NUM>) and send the output from the steering sensors to the controller; and
a fifth motor (<NUM>) in operable communication with the steering motor drive unit, the steering motor drive unit configured to drive the steering control motor.