Retrofit aircraft autothrottle control for aircraft equipped with engine control systems - Patents.com

Abstract

An autothrottle system interfaced with a Fully Automatic Digital Engine Control (FADEC) system having a command input that receives a sensed power control input (PCL) position signaling indicative of an aircraft's manual throttle setting, the autothrottle system generating a synthesized automatic output command signaling that virtualizes electrical characteristics of the sensed PCL position signaling such that the automatic output command signaling is recognized by the FADEC system as the sensed PCL position signaling.

Description

[Technical field]

[0001] (Related Applications) This application claims the benefit of U.S. Provisional Application No. 63 / 271,044, filed October 22, 2021, and U.S. Provisional Application No. 63 / 294,014, filed December 27, 2021, the disclosures of each of which are incorporated herein by reference. (Technical field) This invention relates generally to aviation and aircraft control, and more particularly to automatic throttle control to reduce pilot workload and maintain safe flight characteristics. [Background technology]

[0002] An aircraft automatic throttle system, commonly referred to as an autothrottle, is a system that controls an aircraft's engine with minimal pilot intervention. Such autothrottles provide the ability to achieve truly automated, hands-off control of an aircraft, thereby increasing the aircraft's operating efficiency, reducing costs, for example in fuel consumption, and significantly reducing pilot workload, thereby significantly increasing flight safety. Autothrottles are prevalent in large or newer high-performance aircraft, such as airline passenger jets, modern regional and general aviation jets, and modern turbine-propeller aircraft, which generally incorporate autothrottles as part of an integrated flight management system (FMS). The FMS also provides lateral navigation (LNAV) and vertical navigation (VNAV) autopilot control to control the aircraft according to its flight plan and to keep it operating within a safe operating envelope. An FMS is fundamentally an integrated system built into an aircraft by the aircraft manufacturer, with various sensors and actuators located throughout the aircraft to assess the aircraft's configuration, position, heading, speed, altitude, and performance, among other monitored parameters.

[0003] Because FMS are complex and costly, such systems have traditionally been considered impractical for small aircraft, such as those used in general aviation. Small aircraft may include aircraft with single or multiple engines using pistons or turbines (e.g., light aircraft or very light jets (VLJs)), and typically accommodate ten or fewer passengers. Typically, small aircraft have a maximum takeoff weight (MTOW) of less than 15,000 pounds (6,800 kg). Small aircraft may include disparate systems, such as autopilots, GPS navigation, etc., but such systems are typically not integrated into a complete FMS, as they tend to be offered as options by aircraft manufacturers or retrofitted to existing aircraft. Additionally, certain sensors used in FMS, such as radar-based altimeters, redundant airspeed sensors, etc., are typically not present on small aircraft, making the addition of an FMS even more difficult.

[0004] U.S. Patent Application Serial No. 17 / 675,534, entitled "PILOT INTERFACE FOR AIRCRAFT AUTOTHROTTLE CONTROL," describes an autothrottle system suitable for use with small aircraft that determines control target settings for the aircraft's throttle and dynamically adjusts the throttle according to the control target settings, the disclosure of which is incorporated herein by reference. The autothrottle system can implement an autothrottle control program and control an autothrottle actuator to set and dynamically adjust throttle settings that automatically control engine power of the aircraft. The autothrottle control program can set and dynamically adjust the throttle settings according to different ones of a plurality of autothrottle control modes, each of which defines a corresponding control target set point.

[0005] Small aircraft, particularly small multi-engine aircraft, often employ Full-Authority Digital Engine Control (FADEC) systems that automate the control of various engine parameters during flight based on a set of monitored set points and conditions to provide optimal or near-optimal engine efficiency. For example, a FADEC system may control fuel flow, stator vane position, air bleed valve position, or other such engine parameters based on flight conditions such as air density, throttle lever position, engine temperature, engine pressure, etc. A FADEC system may also enforce certain constraints, such as keeping engine temperature below operational limits. Summary of the Invention [Problem to be solved by the invention]

[0006] Incorporating an autothrottle system into small aircraft equipped with FADEC systems would be desirable, especially as a retrofit. However, this presents a number of challenges. For example, known autothrottle systems operating on non-FADEC aircraft tend to be integrated with the power control lever (PCL) and operate to match fuel control to the aircraft's engine. However, this function (and a wide variety of other functions) is the domain of the FADEC system. When a retrofit autothrottle is operational, it would be detrimental for the autothrottle system to replace the function of the FADEC system.

[0007] Traditionally, replacing a FADEC system with an autothrottle system has meant bypassing the functionality of the FADEC system or adding substantial complexity to the autothrottle system to replace that functionality. Because the engine optimization and operational envelope limiting functions are so important, it is clearly undesirable to omit or disable the functionality of the FADEC system. Adding complexity to an autothrottle system to take over the functionality of a FADEC system would significantly increase the cost of developing, qualifying, and installing such a system, and there would be little market demand for retrofitting such an autothrottle system to an aircraft that already has a FADEC system. In addition, it is highly desirable to maintain existing operating procedures with any retrofit system. The addition of an autothrottle system that overrides an existing FADEC system would tend to complicate the operating procedures that the aircrew must learn.

[0008] For these and other reasons, a practical solution is needed for integrating retrofit autothrottle systems onto FADEC-enabled aircraft. [Means for solving the problem]

[0009] One aspect of the disclosure relates to an autothrottle system interfaced with a Fully Automatic Digital Engine Control (FADEC) system having a command input that receives a sensed power control input (PCL) position signaling indicative of an aircraft's manual throttle setting, and generates an automatic output command signaling synthesized to virtualize electrical characteristics of the sensed PCL position signaling, such that the automatic output command signaling is recognized by the FADEC system as the sensed PCL position signaling.

[0010] According to one embodiment, an aircraft is equipped with a Fully Automatic Digital Engine Control (FADEC) system having a command input that receives a sensed power control input (PCL) position signaling indicative of a manual throttle setting. An autothrottle control device retrofittable to an aircraft includes processing circuitry, memory, and input / output mechanisms. The autothrottle control device is operative to execute instructions that include an autothrottle control program. The autothrottle control device includes an input operative to receive the sensed PCL position signaling and outputs an automatic power command signaling.

[0011] The FADEC interface is electrically connected to the autothrottle controller and to the FADEC system and is controllable by the autothrottle controller to select from among the sensed PCL position signal and the automated power command signal to be connected to the command input in response to an autothrottle engagement signal from the autothrottle controller. The autothrottle control program, when executed, causes the autothrottle controller to determine control target setpoints and generate automatic output command signaling in accordance with the control target setpoints when the system is in an engaged state for autothrottle control. The autothrottle controller is similarly operative to generate an autothrottle engagement signal when the system is in an engaged state for autothrottle control.

[0012] The automatic output command signaling is generated by the autothrottle control device in accordance with the autothrottle control program and synthesized to virtualize the electrical characteristics of the sensed PCL position signaling such that the automatic output command signaling is recognized as the sensed PCL position signaling by the FADEC system.

[0013] A related aspect of the subject matter includes instructions (stored on at least one tangible, non-transitory machine-readable medium) executable on a controller of an autothrottle system to perform operations according to any of the methods described herein.

[0014] In a related aspect, a method is provided for controlling autothrottles in an aircraft that includes a FADEC system having a command input that receives a sensed power control input (PCL) position signaling indicative of a manual throttle setting.

[0015] The method includes the steps of the autothrottle controller executing instructions including an autothrottle control program including determining a control target setpoint, the method further includes the steps of the autothrottle controller receiving a sensed PCL position signaling, the autothrottle controller outputting an automatic output command signaling based on the control target setpoint including synthesizing an electrical characteristic of the sensed PCL position signaling such that the automatic output command signaling is recognizable by the FADEC system as the sensed PCL position signaling, and electrically selecting, under control of the autothrottle controller, a throttle command signal to be coupled to a command input from among the sensed PCL position signaling and the automatic output command signaling.

[0016] Many advantages will become apparent from the detailed description that follows.

[0017] The present invention can be more fully understood from consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings. [Brief description of the drawings]

[0018] [Figure 1A] FIG. 1 is a simplified diagram illustrating an aircraft and the fundamental forces involved in its flight. [Figure 1B] FIG. 2 is a simplified block diagram illustrating the basic relationship between a FADEC system and an autothrottle system when the systems are implemented together in an aircraft according to some embodiments. [Figure 2A]FIG. 1 illustrates an aircraft cockpit or flight deck that may be retrofitted with an autothrottle control in accordance with some embodiments of the present disclosure. [Figure 2B] FIG. 1 illustrates an implementation of an autothrottle control and information display as part of an integrated standby unit (ISU) according to one embodiment. [Diagram 3] FIG. 1 is a high-level block diagram illustrating an autothrottle control system according to some embodiments. [Figure 4] FIG. 1 is a simplified block diagram illustrating components of an autothrottle control device according to an exemplary embodiment. [Diagram 5] FIG. 2 is a simplified block diagram illustrating some of the specific instructions executable by an autothrottle controller according to some embodiments. [Figure 6] FIG. 2 is a state diagram illustrating some basic states of an autothrottle control system according to some embodiments. [Figure 7] FIG. 2 is a simplified block diagram illustrating an example of an electrical interface between an autothrottle system controller and a FADEC system according to some embodiments. [Figure 8] FIG. 1 is a block diagram illustrating a retrofit autothrottle system interfaced with a FADEC system of an aircraft in accordance with an illustrative embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] While the invention is susceptible to various modifications and alternative forms, specific features thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. Rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

[0020] It should be noted that aspects of the present disclosure are applicable to any powered aircraft, such as conventional fuel-burning aircraft (propeller-driven, turboprop, jets, etc.), electric aircraft (battery-powered, solar-powered, or fuel cell-powered), or hybrid-powered aircraft. In the following description, various embodiments are described in the context of one or several types of propulsion or propulsion-energy-delivery systems, but it should be understood that the principles of the described embodiments may be suitably applied to other types of aircraft having other propulsion or propulsion-energy-delivery systems, with appropriate adaptations that are within the skill of an aircraft engineer.

[0021] 1A is a simplified diagram illustrating an aircraft 100 and the fundamental forces involved in its flight. The aircraft 100 generates lift 102 from its forward motion primarily by using the shape and orientation of the aircraft's 100 body (e.g., its wings, fuselage, and control surfaces) to direct air downward. Lift also depends on air density, velocity squared, the viscosity and compressibility of the air, and the surface area through which the air flows. The dependence on the aircraft's 100 body shape is complex and difficult to mathematically model. The effects of the aircraft's 100 pitch, air viscosity (e.g., due to temperature, humidity, altitude), and compressibility on the lift are variable and difficult to derive for a given set of operating conditions.

[0022] Drag 104 is a force that resists the forward motion of the aircraft 100. Drag 104 has many components, including, among others, aerodynamic friction between the air and the surface of the aircraft 100 (skin friction), aerodynamic resistance to the movement of the aircraft 100 through the air (form drag), and drag caused by lift (induced drag), which are similarly difficult to account for in order to predictively calculate drag. Like lift 102, drag 104 depends on many complex factors, including the size, shape, and weight of the aircraft 100, the surface characteristics of the aircraft 100, the fluid properties of the air, and other parameters. In particular, different parameters of drag 104 become dominant at different airspeeds. At low airspeeds, the main component of drag 104 is induced drag. As the aircraft 100 increases its airspeed, lift 102 is more easily generated and induced drag actually decreases. However, as airspeed increases, other drag components (collectively referred to as parasitic drag) increase.

[0023] Thrust 106 is the propulsive force generated by the aircraft 100 to overcome the drag 104. Producing thrust requires the consumption of fuel or other on-board energy sources (e.g., electricity in the case of a battery-powered aircraft). The magnitude of thrust depends on a number of parameters related to the aircraft 100's propulsion system, such as the type and number of engines, and throttle settings. Weight 108 is a combination of gravity and the mass of the aircraft 100, including the mass of the airframe, the mass of the fuel (which is a time-varying quantity in the case of a fuel-burning aircraft), and any payload (people, cargo, etc., which may also vary dynamically, such as in the case of an airdrop operation) on the aircraft 100. The dynamic variation of weight 108 means that the magnitudes of the lift 102 and drag 104 also change over time during the flight of the aircraft 100.

[0024] The performance of the aircraft 100 is limited by various physical constraints. For example, the airspeed is substantially limited by the aerodynamics and structural strength of the aircraft 100 airframe, as well as the available thrust. There are also limitations to the power, thrust, or torque that the engines, shafts, propellers, and other associated components can withstand. Similarly, the engines are limited by the temperatures at which the engine components or fluids can operate. These various constraints are typically expressed as maximum ratings provided by the engine manufacturer.

[0025] During operation of the aircraft 100, various constraints govern the performance limitations of the aircraft depending on the flight phase, air density and temperature, and other parameters. For example, during takeoff and climb, the performance of the aircraft 100 tends to be limited primarily by maximum engine power, thrust, or torque, while during cruise, the performance of the aircraft 100 tends to be limited by engine temperature.

[0026] Because both lift 102 and drag 104 forces are complex and varying, it is important for the pilot of the aircraft 100 to be able to determine a desired operating point, e.g. - maximum power, thrust and torque operating points during takeoff or climb; - maximum temperature operating point during cruise, - Maximum efficiency operating point for maximum endurance flight So, it is difficult to maintain optimal throttle settings, taking into account the current altitude, weight, and air conditions, for takeoff, climb, or cruise.

[0027] According to some embodiments, an autothrottle control system (sometimes interchangeably referred to as an autothrottle system or simply an autothrottle) is employed in an aircraft to dynamically adjust engine power to maintain an operating point, or set of operating points, for a current flight phase. The operating point can be set and changed by the pilot using the autothrottle system's interface, including the PCL. The operating point can also be automatically adjusted by the autothrottle system to maintain a safe or optimal flight envelope.

[0028] In another related aspect, the PCL is accompanied by a set of simple input devices such as switches, push buttons, etc. to facilitate pilot control of the autothrottle, including an input to set the autothrottle control mode.

[0029] 1B is a simplified block diagram illustrating the basic relationship between a FADEC system and an autothrottle system when the systems are implemented together on an aircraft according to some embodiments. As shown, the aircraft's engines 120 are controlled by a FADEC system 122 that generates engine control signaling 123. The engine control signaling 123 includes various signals to control actuators such as throttle settings, stator vane position, air bleed valve position, etc. of the engines 120 based on flight conditions including air density, engine temperature, engine pressure, and other such parameters, as well as manual throttle input.

[0030] FADEC system 122 receives inputs including a manual throttle input 130 and sensed conditions 132. An example of a manual throttle input 130 is the position of the PCL. Sensed conditions 132 include outputs of temperature sensors, pressure sensors, etc., and provide flight condition information to FADEC system 122.

[0031] The autothrottle system 124 similarly receives a manual throttle input 130. In various implementations, the autothrottle system 124 reads the same PCL position sensor as read by the FADEC system 122. In other implementations, the autothrottle system 124 uses a dedicated PCL sensor that is different from the one used by the FADEC system 122. The autothrottle system 124 generates an autothrottle (AT) output 125, which is received as an input by the FADEC system. In some embodiments, as described in more detail below, the autothrottle system 124 includes a FADEC interface that controls the PCL position input to the FADEC system 122 to select between the manual throttle input 130 or the AT output 125.

[0032] 2A is a diagram illustrating a cockpit or flight deck 200 (these terms may be used interchangeably herein) of an aircraft, such as aircraft 100, in which an autothrottle pilot interface control is implemented according to some embodiments of the present disclosure. Cockpit 200 includes, in this example, a PCL 202 that is pivotally mounted to the center console and movable in a fore-aft direction along an arcuate path of travel.

[0033] The PCL 202 may be a single lever, as shown in the illustrated embodiment, or may comprise multiple levers (not shown) in the case of a multi-engine aircraft. For simplicity, the one or more power control levers will be referred to herein simply as a "PCL" unless specific reference to multiple levers is intended. In more general embodiments, the power control input may be provided in another form other than a lever. For example, the power control input may be implemented as at least one slider, knob, wheel, pedal, or other pilot-actuable mechanism (or set of mechanisms). Again, for simplicity, the power control input (whatever its form) will be referred to simply as a "PCL."

[0034] In a FADEC-enabled aircraft, the PCL 202 is connected to each of the engines and fuel supply systems of the aircraft 100 via a FADEC system controller. For example, the FADEC system reads signaling indicating the position or movement of the PCL and interprets the position or movement as a pilot's call to set or adjust engine power. For example, in some implementations, the PCL position (selected thrust position) information is monitored by the FADEC controller via a PCL angle measurement sensor, such as a potentiometer, a rotary variable differential transformer (RVDT) or a rotary variable inductance transducer (RVIT) sensor, among other types of sensors. Furthermore, the FADEC system controller actuates or adjusts actuators that adjust engine power (e.g., fuel or combustion air flow, or, in the case of an electric aircraft, power supply to the engine) based on the position or movement of the PCL. Many other engine parameters can be controlled by the FADEC system as well.

[0035] The autothrottle system may also be arranged to sense and monitor the position of the PCL 202 as described in U.S. Pat. No. 11,027,854, the disclosure of which is incorporated herein by reference, or by other suitable sensing means. The PCL 202 may thus function as part of the autothrottle pilot interface control. In one type of embodiment, the autothrottle system uses an angle measurement sensor that is part of the FADEC system and is also read by the autothrottle system to determine the PCL position. In other embodiments, the autothrottle system utilizes an additional dedicated sensor to measure the PCL position independent of the FADEC system sensor.

[0036] 2A shows additional autothrottle pilot interface controls: an autothrottle actuation control 204, a takeoff / go-around control 206, and an autothrottle mode selector 208. These controls 204-208 are implemented as momentary push button switches according to the illustrated embodiment. However, in other embodiments, the controls 204-208 can be implemented using other types of input mechanisms, such as a selector knob, multiple rocker switches, multi-position selector switches, toggle switches, push-on / push-off switches, multiple soft key controls (e.g., via a touch screen), etc.

[0037] Additionally, an autothrottle mode display 210 is provided. The autothrottle mode display 210 may include LED or LCD segments, a matrix of LED or LCD devices, or other suitable display technology, along with display decoders or driver circuitry that interfaces the display to the autothrottle control device, as described below. In the illustrated embodiment, the autothrottle mode display 210 is integral with the autothrottle mode selector 208 such that information is displayed on the pilot-facing surface of the autothrottle mode selector 208. In other embodiments, the autothrottle mode display 210 is separate from the autothrottle mode selector 208 and may be located elsewhere on a control panel of the cockpit 200. In yet other embodiments, the autothrottle mode display 210 is implemented using a general purpose information display present in the cockpit 200, such as an instrument display or navigation display screen, or as part of the information displayed on a head-up display.

[0038] 2B illustrates an implementation of autothrottle controls and information display as part of an integrated standby unit (ISU) according to an embodiment. As shown, the ISU 220 is a user interface that includes a multifunction display 222 and various autothrottle controls including a selector knob 224, indicator lights 226, and push buttons 228A and 228B. The multifunction display 222 may display information related to autothrottle operation, such as an AT mode indication 230, an AT setting 232, etc. The indicator light 226 may indicate the status of the autothrottle, such as armed / disarmed, engaged / disengaged, etc. For example, the indicator light 226 may illuminate green when the autothrottle is engaged, illuminate amber when the autothrottle is disengaged, and be unilluminated when the autothrottle is disengaged.

[0039] A push button 228A, labeled A / T PWR, may function as an enable / disable control for the autothrottle system. A push button 228B, labeled MENU, may function as a control for the function of the selector knob 224. Thus, depending on the operating situation, the selector knob 224 may operate as an input for selecting an autothrottle mode, an autothrottle control target setpoint, etc. The selector knob 224 may provide a push button input in addition to a rotary input. In a related embodiment, at least a portion of the circuitry of the autothrottle system, such as a controller, may be contained within the ISU 220.

[0040] In addition to autothrottle information, the multifunction display 222 may display various flight and engine related conditions, such as airspeed, altitude, heading, horizon, and various monitored engine conditions, all of which may be redundant to other, primary, instruments in the instrument cluster of the aircraft's cockpit and consistent with information displayed on a conventional standby unit. Notably, in some embodiments, the ISU 220 has exterior dimensions that match the aircraft's original conventional standby unit that it will replace. For example, the ISU 220 may fit into an instrument panel cutout that was originally made for the conventional standby unit. Advantageously, the addition of the ISU 220 does not change the guaranteed field of view of the aircraft, which is particularly beneficial in retrofit applications.

[0041] 3 is a block diagram illustrating an autothrottle control system 300 according to some embodiments. As shown, the system 300 includes a manual throttle input 302, which may take the form of a PCL, such as PCL 202, or other types of inputs. For example, a pilot interface may be provided in the form of a local operator interface (LOI) device. The LOI device may include or implement one or more push buttons, knobs, switches, touch screen controls, joysticks, trackballs, touch pads, microphones, voice recognition systems, etc., to accept inputs from the pilot, such as enable / disable, engage / disengage, control mode selection, speed / torque settings, etc. The LOI device may include displays or indicator lights that indicate the operating status of the autothrottle system as well as the settings of the autothrottle control.

[0042] The throttle setting sensor 308 is positioned to detect the position or movement of the PCL and provides a PCL position signaling 309A to the autothrottle controller 310 and the FADEC interface 304. In particular, the signaling 309A and 309B represent the effect of manual movement of the PCL when the manual PCL input 302 is applied.

[0043] FADEC interface 304, examples of which are described in further detail below, facilitates coordination between the autothrottle system and the FADEC system. When the autothrottle system is engaged, an autothrottle controller 310 generates command signaling 305 that is selectively provided to the FADEC system via FADEC interface 304. The FADEC system automatically generates throttle setpoints 306 to adjust engine power and control other parameters to optimize engine performance and reliability. When the autothrottle system is disengaged, FADEC interface 304 does not pass command signaling 305 to the FADEC system.

[0044] As described in more detail below, in one type of implementation, the FADEC interface 304 selects between the command signaling 305 from the autothrottle control 310 and the sensed PCL position signaling 309B depending on whether the autothrottle system is engaged or disengaged. Additionally, as described in more detail below, in some embodiments, the command signaling 305 is a virtual PCL position signal that is synthesized to mimic the actual PCL position signaling 309B as if the PCL had been manually positioned or moved. The virtual PCL position signal virtualizes the electrical characteristics of the actual sensed PCL position signaling such that the automatic output command signaling generated by the autothrottle system is recognized by the FADEC system as the sensed PCL position signaling.

[0045] In some embodiments, the autothrottle control 310 monitors the PCL position via the PCL position sensor 308 by receiving the PCL position signaling 309A. When the autothrottle control 310 is engaged and generating command signaling 305, the PCL position is simultaneously monitored for any manual throttle input 302. In this operating state, in the absence of manual throttle input 302, the autothrottle control 310 maintains its automatic control mode, but if a manual throttle input 302 is detected, the autothrottle control 310 disengages and provides notification of the disengagement to the pilot. Such notification may include a visual indication using a light or display device, or an audible notification. In some implementations, the notification is repeated until the pilot acknowledges the disengagement of the autothrottle control.

[0046] Autothrottle control 310 generates command signaling 305 to FADEC interface 304 based on a number of inputs. Autothrottle mode input 312 is provided by the pilot of aircraft 100 via an appropriate input, such as autothrottle mode selector 208 or controls 224 and 228 of ISU 220. The inputs may include parameters such as engaging / disengaging autothrottle control 310, selecting an autothrottle mode, or selecting from one or more available autothrottle programs that define the autothrottle behavior or operating objectives.

[0047] Other inputs to the autothrottle control 310 may include an autothrottle activate input 314, and an autothrottle TO-GA command input 316. The autothrottle activate input 314 may be provided via the autothrottle activate control 204 and may be operated in various patterns (e.g., short press / long press) by the pilot to select between an engaged and an enabled state of the autothrottle control, as well as to completely disengage and deactivate the autothrottle. The autothrottle takeoff / go-around (TO-GA) input is provided via the takeoff / go-around control 206 and may be operated by the pilot to place the autothrottle in a takeoff autothrottle program when the aircraft 100 is on the ground, or in a climb (go-around) program when the aircraft 100 is airborne. Additional functions may be assigned to the inputs 312-316, which may be operated individually or in combination with the manual throttle input 302 via the PCL 202. For example, the autothrottle actuation input 314 can further be actuated by the pilot in a particular pattern (e.g., double press) to toggle between coarse or fine adjustments of the autothrottle. Similarly, activation of the autothrottle actuation input 314 in conjunction with the positioning of the PCL 202 can be used by the pilot to set or reset the autothrottle control target setpoints.

[0048] The autothrottle control 310 may also receive various inputs from sensors such as an engine temperature sensor 320, an engine torque sensor 322, and an airspeed sensor 324, along with other available sensors on the aircraft 100, such as an altimeter, a fuel consumption rate sensor, etc.

[0049] FIG. 4 is a simplified block diagram illustrating components of an autothrottle controller 310 according to one embodiment. The autothrottle controller 310 includes a central processing unit (CPU) 410, which may include one or more processor cores 412. The memory circuit 414 may include static or dynamic random access memory (RAM) and a memory controller circuit interfaced with the CPU 410. The instructions 416 may be stored in a read only memory (ROM) device or an electrically erasable programmable read only memory (EEPROM) device, such as a flash EEPROM device, interfaced with the memory controller circuit of the CPU 410 or the memory 414. The input / output (I / O) controller 418 includes an interface to the various inputs and command signaling 305 outputs described above. In some implementations, the I / O controller 418 may include a universal asynchronous receiver-transmitter (UART) for serial communication, a parallel port, or a data bus interface. The I / O controller 418 may interface with the memory controller of the CPU 410 or the memory 414.

[0050] The ADC / DAC 420 includes an analog-to-digital (A / D) converter and a digital-to-analog converter (D / A) and can interface with one or more sensors or actuators. In some embodiments, the ADC / DAC interfaces with the PCL position sensor 308 (receives the PCL position signaling 309A). The ADC / DAC 420 can also interface with the FADEC interface 304, in which case the ADC / DAC 420 can synthesize the command signaling 305. The ADC / DAC 420 can interface with the CPU 410 or a memory controller of the memory 414.

[0051] The autothrottle controller 310 is operable to execute instructions 416 to perform the functions of the autothrottle control system 300. Figure 5 is a simplified block diagram illustrating a portion of the instructions 416 according to some embodiments. When operating the autothrottle control system 300 via the autothrottle mode input 312 or the autothrottle TO-GA input 316, the pilot of the aircraft 100 can select from among certain available programs that dictate the control algorithm for the autothrottle operation. Additionally, the operating state of the autothrottle is selectable via the autothrottle mode input 312 and the autothrottle activation input 314.

[0052] The instructions 416 include a user interface process 502, a flight safety monitoring process 504, an airspeed program 510, an engine thrust program 512, an endurance maximizer program 514, an airspeed maximizer program 516, a takeoff / go-around program 518, and a FADEC interface process 520. Each process or program includes a set of instructions executable by the autothrottle controller 310 to operate the autothrottle control system 300. Generally, each of the programs 510-518 is executed independently (although one program may automatically transition to another program). However, the user interface process 502, the flight safety monitoring process 504, and the FADEC interface process 520 are executed consecutively.

[0053] The user interface process 502 operates to monitor all user inputs (and optionally certain sensors) and set the autothrottle control system 300 to various states in response. Figure 6 is a state diagram illustrating several basic states, according to one embodiment. The basic states include a disarmed state 602 and an armed state 604. The armed state 604 includes an engaged state 612 and a disengaged state 614. The autothrottle control system 300 transitions from the disarmed state 602 to the disarmed state 614 via transition 603, and from the disengaged state 614 back to the disarmed state 602 via transition 615. The autothrottle control system 300 transitions from the disarmed state 602 to the armed-engaged state 612 via transition 605, and from the armed-engaged state 612 back to the disarmed state 602 via transition 613. As shown, in an enabled state, the autothrottle control system 300 transitions between an engaged state 612 and a disengaged state 614 via transitions 617 and 619 .

[0054] In the deactivated state 602, the autothrottle control system 300 is generally inoperative. In some embodiments it may be completely disabled, or in other embodiments the autothrottle control system 300 may be minimally operable to monitor certain safety-related indicators, such as over / under speed, over temperature, over torque, and may autonomously engage autopilot controls in response to unsafe conditions to restore and maintain a safe flight envelope. In the activated state 604, the autothrottle control system 300 monitors control inputs and determines autothrottle control target setpoints. In the activated-engaged state 612, the autothrottle control system 300 generates command signaling 305 according to the control target setpoints.

[0055] Table 1 below summarizes the various operations of pilot inputs processed by user interface process 502 according to one embodiment. (Table 1) TIFF2024542877000002.tif164170

[0056] In one embodiment, as shown in Figure 2A, the autothrottle mode selector 208 is a button used to initially enable the autothrottle system and to switch between autothrottle modes. In another embodiment, as shown in Figure 2B, the A / T PWR button 228A has a similar function. The modes are described in more detail below and can include, but are not limited to: TO - Takeoff mode CLB-Climbing Mode CRZ-Cruise-Maximum Power Mode THR - Thrust Maintenance Mode GA - Go-Around Mode ###-Settings-Speed ​​Control Mode OFF-Not linked

[0057] 2A, the mode selector 208 button mounted on the instrument panel may incorporate a display 210 (e.g., a backlit LCD or LED array on the button face) for displaying the autothrottle mode and the speed target. The autothrottle mode may be displayed in a first color, such as white, when in the armed-disengaged state 614 and in a second color, such as green, when in the armed-engaged state 612.

[0058] 2B embodiment, the A / T PWR button 228A has a similar function as the mode selector 208 button. The multifunction display 222 and indicator lights 226 are operative to indicate the status of the autothrottle system.

[0059] Pressing the autothrottle mode selector 208 button or the A / T button 228A when not in the armed state 604 arms the autothrottle. In one embodiment, the autothrottle is initially armed at the current torque or airspeed. In some embodiments, repeatedly pressing the autothrottle mode selector 208 button or the A / T PWR button 228A toggles between thrust and speed modes (thrust armed, speed armed, and off for disengaged). In some embodiments, pressing and holding the autothrottle mode selector 208 button or the A / T PWR button 228A (>1 second) engages or disengages the autothrottle. The autothrottle can only be engaged from the armed state 604.

[0060] In other embodiments, the selector knob 224 can be used to facilitate autothrottle mode selection input rather than or in addition to the A / T PWR button 228A. A wide variety of input patterns and other types of user interface controls are contemplated to facilitate user interaction with the autothrottle system.

[0061] In some embodiments, when the autothrottle system 300 is in the armed state 604, the PCL 202 may be moved to adjust the autothrottle target torque or speed values. The adjusted settings are displayed on the display 210. In particular, the autothrottle settings may be adjusted and set using manual movement of the PCL 202 before the set parameters are actually reached while the aircraft is in flight.

[0062] In some embodiments, the autothrottle actuation control 204 is a button, located on the right side of the PCL handle in one embodiment. Pressing the autothrottle actuation control 204 button will either place the autothrottle system 300 in an enabled-engaged state 612 or disengage the autothrottle to an enabled-disengaged state 614. Pressing the autothrottle actuation control 204 button again will re-engage the (enabled) autothrottle to state 612 and actively maintain the updated torque or speed target. In speed control mode, pressing the autothrottle actuation control 204 button a second time while in the enabled-disengaged state 614 will toggle between coarse or fine target speed adjustment. Pressing and holding the autothrottle actuation control 204 button (>1 second) will fully disengage the autothrottle and return to the deactivated state 602.

[0063] In one embodiment, the takeoff / go-around control 206 is implemented as a button on the left side of the PCL handle. When the autothrottle system is in the armed-disengaged state 614 and the mode is set to takeoff (TO) mode, actuating the takeoff / go-around control 206 button on the throttle handle will activate the TO mode and the command signaling 305 will automatically adjust to the maximum continuous thrust setting. When the aircraft 100 is airborne, pressing the takeoff / go-around control 206 button while the autothrottle is in either armed state 612, 614 will activate the go-around (GA) mode and the command signaling 305 will automatically adjust to maximum continuous thrust under the control of the autothrottle.

[0064] 5, flight safety monitoring process 504 operates to monitor aircraft sensors (e.g., engine temperature sensor 320, engine torque sensor 322, airspeed sensor 324, altimeter, etc.) and compare the current operating state or performance or condition of aircraft 100 with pre-established constraints of aircraft 100 and its engines to ensure the aircraft is operating within its safe flight envelope. For example, overspeed / underspeed at the current altitude, temperature limits, torque limits, differential torque in multi-engine aircraft, etc. may be monitored and the command signaling 305 may be adjusted to override control of the autothrottle system to keep the aircraft within safe operating conditions.

[0065] The airspeed program 510 causes the autothrottle to perform basic fixed-airspeed control (set speed control mode). The program 510 accepts pilot input to set a particular airspeed, which may be set, for example, via manual throttle input 302 by moving the PCL 202 or selector knob 224. The airspeed program 510 then generates command signaling 305 to increase engine power if the indicated airspeed drops below the setpoint and decrease engine power if the indicated airspeed rises above the setpoint. If the autothrottle is engaged in set speed control mode, the pilot can disengage the autothrottle to an enabled-disengaged state 614, for example by pressing a button on the autothrottle actuation control 204 or the A / T PWR button 228A, and select a new target speed (which may be displayed in white on the display 210) by moving the PCL 202 or selector knob 224. After the target speed is selected, pressing the autothrottle actuation control 204 button or the A / T PWR button 228A again will resume the autothrottle to maintain the selected airspeed. In the ARMED-DISENGAGED state 614, while in set speed control mode, movement of the PCL 202 or A / T PWR button 228A may be translated into changes in the target speed rounded to 5 knot increments. For example, double clicking the autothrottle actuation control 204 button or the selector knob 224 may adjust the target speed in (fine) 1 knot increments.

[0066] The engine thrust program 512 executes a thrust maintenance mode (THR) to maintain the current engine torque. The program 512 may automatically reduce the torque to maintain applicable power and temperature limits based on the current rate of climb. While the autothrottles are in the armed-engaged state 612 in THR mode, the pilot may press a button on the autothrottle actuation control 204 to temporarily disengage the autothrottles to the armed-disengaged state 614 and manually move the PCL 202 or A / T PWR button 228A to select a new thrust setting. After adjusting the torque, the autothrottles may be re-engaged to maintain the new torque by again pressing a button on the autothrottle actuation control 204 or the A / T PWR button 228A.

[0067] The endurance maximization program 512 implements a dynamic airspeed control algorithm to determine and maintain an efficient operating point for the aircraft 100 such that the aircraft is operating at or near its maximum lift to drag (L / D) ratio under the prevailing conditions, as described in U.S. application Ser. No. 17 / 359,019, the disclosure of which is incorporated herein by reference.

[0068] The airspeed maximization program 516 implements the dynamic control algorithm of the autothrottle system 300 for cruise operation, monitoring engine temperature (e.g., via engine temperature sensor 320) and adjusting the command signaling 305 to request maximum speed while maintaining the engine temperature at or near the applicable maximum operating temperature limit.

[0069] The takeoff / go-around program 518 implements the takeoff mode (TO), climb mode (CLB), cruise mode (CRZ), and go-around mode (GA), as well as the automatic transitions between these modes. The TO is initiated while the aircraft 100 is on the ground. In accordance with the takeoff program 518, the command signaling 305 is set to maintain maximum continuous torque (MCT). The TO is enabled (while on the ground) by pressing a button on the mode selector 208 or the A / T PWR button 228A. Pressing the button on the mode selector 208 or the A / T PWR button 228A again deactivates the TO.

[0070] With the TO deactivated, the pilot can initiate an autothrottle takeoff by pressing a button on the takeoff / go-around control 206 on the PCL handle, as described above. This engages the autothrottles 300 and causes them to dynamically adjust command signaling 305 to gradually increase power to the MCT. Under such control, thrust will be maintained at the MCT until manually or automatically reduced to climb power.

[0071] In accordance with the takeoff / go-around program 518, the TO transitions to climb mode (CLB) upon meeting preset mode transition criteria. In one embodiment, the mode transition criteria includes a preset duration in the MCT (e.g., 2-5 minutes). In another embodiment, the mode transition criteria for entering the CLB is an altitude gain, which can be measured by the aircraft 100's available barometric altimeter (e.g., a 400 foot altitude gain from the altitude at which the TO was initiated). This approach uses readily available altimetry data rather than relying on radar-based altimeters or other expensive instruments not typically found on many small aircraft.

[0072] In a related embodiment, the transition criteria for entering CLB includes manual reduction of the PCL 202 by the pilot during TO (e.g., actuating a button on the autothrottle actuation control 204 to transition the autothrottle state to Armed-Disengaged state 614, manually repositioning the PCL 202 to reduce power, and then again actuating the button on the actuation control 204 to re-engage the autothrottle to engaged state 612). In other embodiments, CLB mode can be initiated by action of other controls, such as holding down the selector knob 224 for more than one second if the autothrottle is already engaged.

[0073] In climb mode (CLB), the autothrottles will maintain the MCT but will automatically reduce power to maintain engine temperature limits. Upon aborting takeoff or climb and leveling off (automatically detected by monitoring the available altimeter as a small climb rate, such as less than 200 feet per minute), the autothrottles will transition to cruise mode (CRZ) and reduce power to the maximum cruise power setting.

[0074] In cruise mode (CRZ), the autothrottle controls the PCL to produce maximum cruising torque while adhering to engine temperature limits.

[0075] The go-around mode (GA) is similar to the TO, except that the GA is activated while the autothrottles are in either the enabled-engaged state 612 or the enabled-disengaged state 614 and while the aircraft 100 is airborne. Under these conditions, the GA is activated upon actuation of a button on the takeoff / go-around control 206 by the pilot. Once activated, the GA functions essentially the same as the TO, i.e., the autothrottles set the PCL for the MCT and maintain this setting until conditions are met to transition to the climb mode (CLB) or cruise mode (CRZ).

[0076] The FADEC interface process 520 operates to determine the signaling and value ranges of the command signaling 305. In particular, when the autothrottle is in the engaged state 612, the command signaling 305 replaces the sensed PCL position signaling 309B as an input to the FADEC interface 304 (FIG. 3). Thus, in some embodiments, the autothrottle controller 310, under control of the FADEC interface process 520, learns the electrical characteristics of the PCL position signaling 309B by sampling and quantizing the signaling using an analog-to-digital converter of the ADC / DAC 420 (FIG. 4) during an initial configuration process. As an example of initial configuration, the PCL 202 may be moved from one position limit to another while the autothrottle controller 310 reads and stores the sampled and quantized PCL position signaling 309B. Once the autothrottle controller 310 has completed learning the PCL position signaling 309B, under the control of the FADEC interface process 520, it can synthesize a virtual PCL position signaling to be used as the command signaling 305.

[0077] FIG. 7 is a simplified block diagram illustrating an example of an electrical interface between an autothrottle system controller and a FADEC system, according to some embodiments. As shown, a FADEC controller 702, which may be pre-installed on the aircraft 100, conventionally receives a PCL position signaling 705 from a PCL sensor 704. The PCL sensor 704 may be implemented as one or more angular position sensors, such as a potentiometer, an RVDT sensor, an RVIT sensor, etc. In a single-engine aircraft, there may be only a single PCL, in which case a single PCL position sensor may be used. In a multi-engine aircraft with multiple PCLs, a PCL sensor may be used for each PCL. In other implementations, multiple PCL position sensors may be used per PCL for redundancy. For clarity, this description illustrates one example of a PCL sensor 704, but it should be understood that the principles described herein are readily applicable to multiple PCL / multiple PCL sensor configurations.

[0078] The FADEC controller 702 can generate an excitation signal 707 that is provided to a PCL sensor 704. As a result, the PCL sensor generates a PCL position signaling 705 based on a combination of the excitation signal 707 and the angular position of a PCL, such as PCL 202 (FIG. 2A). In the absence of an autothrottle system, the PCL position signaling 705 is effectively a throttle command input 715 to the FADEC controller 702, which is read by the FADEC controller 702 to determine the pilot's intended throttle setting.

[0079] In some embodiments, the PCL actuator is not provided as part of the autothrottle system. Thus, when the autothrottle system is engaged, the thrust command is virtualized or mimicked instead of physically moving the PCL. Thus, there is not always a one-to-one correspondence between the PCL position and the thrust commanded by the autothrottle. When the autothrottle is engaged, the PCL remains in the position last manually set. However, when the autothrottle is engaged, the pilot can monitor the autothrottle generated throttle lever settings and autothrottle mode on the ISU display for real-time feedback. The pilot can disengage the autothrottle at any time and provide a manual throttle level command. In some embodiments, manually moving the PCL while the autothrottle system is engaged immediately transitions the autothrottle state from the engaged state 612 to the disengaged state 614 (FIG. 6).

[0080] The autothrottle control is selectively coupled or decoupled from the throttle command input to the FADEC control 702 based on the state of the autothrottle system. This coupling or decoupling is accomplished by a FADEC interface 714, which is an example of a FADEC interface 304 (FIG. 3). For example, when the autothrottle system is in the engaged state 612 (FIG. 6), the FADEC interface 714 selects the virtual PCL position signaling 711 instead of the PCL position signaling 705 as the throttle command input 715. In other states, the FADEC interface reverts to selecting the PCL position signaling 705 as the throttle command input 715.

[0081] Notably, the excitation signal 707 does not need to be decoupled from the PCL sensor 704. In other words, in various embodiments, the excitation signal 707 is always provided to the PCL sensor 704 regardless of the operation of the autothrottle system.

[0082] In various embodiments, the FADEC interface 714 may be implemented as electromechanical relays, such as transmission gates, or semiconductor switches with appropriate supporting circuitry.

[0083] The selection of virtual PCL position signaling 711 or PCL position signaling 705 is made in response to an AT engagement signal 713 generated by autothrottle control device 710. In a related embodiment, the autothrottle system is designed to have a fail-safe operation such that in the event of a failure or malfunction of the autothrottle system, the AT engagement signal 713 is not asserted. Similarly, the FADEC interface 714 is configured such that the default selection (in the absence of the AT engagement signal 713) is PCL position signaling 705.

[0084] To generate the virtual PCL position signaling, the autothrottle controller 710 uses the PCL position signaling 705 learned during initial system configuration and operates a digital-to-analog converter (DAC) to synthesize a signal representative of the determined throttle setting and provides it to the FADEC interface 714. In some implementations, such as using an RVDT sensor, the PCL position signaling 705 is linear over the range of the PCL. Thus, the virtual PCL position signaling 711 may be linearly interpolated. In other implementations, a suitable transfer function or calibration curve may be utilized. In some implementations, the excitation signal 707 is not required by the autothrottle controller 310 to generate the virtual PCL signaling, while in other implementations the autothrottle controller 310 samples, quantizes, and retrieves the excitation signal 707 and generates the appropriate virtual PCL position signaling 711 based on the retrieved excitation signal 707 and the PCL position signaling 705.

[0085] In a related embodiment, the autothrottle system utilizes its own dedicated PCL position sensor that operates independently of the PCL sensor conventionally supplied as part of the FADEC system.

[0086] FIG. 8 is a block diagram illustrating a retrofit autothrottle system interfaced with a twin engine aircraft FADEC system according to one embodiment. As shown, the routing and connection of RVDT sensor signals between the left (LH) & right (RH) PCLs in the throttle quadrant of the aircraft cockpit and the LH&RH FADEC controllers 800A, 800B in the tail cone area of ​​the aircraft are shown through connectors 802. The RVDT sensors provide the angular position of the throttle levers, which are manually controlled by the pilot of the aircraft, to the FADEC. The FADEC provides engine fuel control based on this throttle lever position information. Existing redundancy is shown provided to control each engine using LH&RH RVDT sensor channels A and B and LH&RH FADEC channels A and B.

[0087] Redundancy of the existing engine control is maintained through the use of pass-through connections and normally closed contacts of relays in a relay box (RRB) that is part of the retrofit autothrottle system. The RVDT excitation voltage from the FADEC to the RVDT sensor passes through the RRB (not switched) and is also monitored by the autothrottle controller. Only the RVDT signal is switched by the RRB. The RVDT relay box relays are switched to normally open contacts by a switching output (e.g., +28V DC) of the retrofit autothrottle controller 810 when the autothrottle function in the engaged state 612 (FIG. 6) is active.

[0088] When the autothrottle is in the engaged state 612, the autothrottle controller 810 outputs a virtual PCL position RVDT signal via the user interface along with the received FADEC RVDT excitation voltage, the current autothrottle operating mode, and the pilot selected thrust target. These autothrottle control virtual RVDT signals are sent to the FADEC via the RRB to provide the autothrottle commanded PCL position to the FADEC. Engine performance is monitored by the FADEC and provided to the autothrottle controller 810 via a data bus as shown, including engine data outputs.

[0089] The unlikely event of a fault condition of the +28VDC switched output of the autothrottle controller 810, which causes the +28VDC output from the ISU to be maintained even when the autothrottle function of the autothrottle controller 810 is not engaged, is mitigated by using a manual control switch in the retrofit user interface UI switch / annunciator to disconnect the connection between the coil of the RRB relay and the +28VDC output of the autothrottle controller 810.

[0090] A failure that causes the normally open contacts of a single individual relay to melt in the closed position is mitigated by using the other individual relay to switch the other RVDT signals. In this way, if a single relay fails, the other relay provides a path for the redundant RVDT signals.

[0091] A retrofit interface as described in this embodiment advantageously facilitates installation without substantial wiring changes, supporting the potential for one-day installation of a retrofit autothrottle system for existing FADEC-equipped aircraft.

[0092] Additional Notes and Examples Example 1 is a system for controlling an autothrottle on an aircraft having a fully automatic digital engine control (FADEC) system having a command input that receives a detected power control input (PCL) position signaling indicative of a manual throttle setting, the system comprising: an autothrottle controller including processing circuitry, memory, and input / output mechanisms, operable to execute instructions including an autothrottle control program, including an input operable to receive the detected PCL position signaling, and operable to output automatic power command signaling; and a FADEC interface electrically connected to the autothrottle controller and the FADEC system, for controlling the detected PCL position signaling and the automatic throttle setting. and a FADEC interface controllable by the autothrottle control device to select from among the output command signalings one to be connected to the command input; wherein the autothrottle control program, when executed, causes the autothrottle control device to determine a control target setpoint and generate automatic output command signaling in accordance with the control target setpoint when the system is in an engaged state for autothrottle control; the automatic output command signaling is generated by the autothrottle control device in accordance with the autothrottle control program and is synthesized to virtualize electrical characteristics of the sensed PCL position signaling such that the automatic output command signaling is recognizable by the FADEC system as a sensed PCL position signaling.

[0093] In example 2, the subject matter of example 1 includes the FADEC interface including an electrical selection switch that defaults to selecting sensed PCL position signaling when the system is not in an engaged state for autothrottle control.

[0094] In Example 3, the subject matter of Example 2 includes the autothrottle control and FADEC interface configured for safe failure and an electrical select switch selects automatic output command signaling only when the autothrottle control is fully functional and engaged.

[0095] In example 4, the subject matter of examples 1-3 includes where the sensed PCL position signaling is generated by an angular position sensor positioned to detect an angular position of a manually movable lever.

[0096] In example 5, the subject matter of example 4 includes the angular position sensor operative to receive an excitation signal from the FADEC system, the excitation signal also being received by the autothrottle control device.

[0097] In example 6, the subject matter of examples 1-5 includes that the automatic output command signaling is generated and automatically adjusted by the autothrottle controller in accordance with an autothrottle control program, independent of the manual throttle setting.

[0098] In example seven, the subject matter of examples one through six includes an input of an autothrottle control device operative to receive a sensed PCL position signaling, the input receiving the same sensed PCL position signaling as is received by the FADEC system.

[0099] In example eight, the subject matter of examples one-seven includes the autothrottle controller being operable to execute instructions including a FADEC interface process that, when executed, causes the autothrottle controller to learn electrical characteristics of sensed PCL position signaling during configuration of the autothrottle controller for the aircraft.

[0100] In example 9, the subject matter of examples 1-8 includes the autothrottle control device being operable to generate an autothrottle engagement signal when the system is in an engagement state for autothrottle control, and the FADEC interface being operable in response to the autothrottle engagement signal to select from among the sensed PCL position signaling and the automatic output command signaling to be connected to the command input.

[0101] In example 10, the subject matter of examples 1-9 includes the autothrottle control device being operable to transition out of an engaged state for autothrottle control in response to a detected change in the manual throttle setting based on the detected PCL position signaling.

[0102] Example 11 is a method for controlling an autothrottle on an aircraft having a fully automatic digital engine control (FADEC) system having a command input that receives a detected power control input (PCL) position signaling indicative of a manual throttle setting, the method including the steps of: an autothrottle controller executing instructions including an autothrottle control program including determining a control target setting; the autothrottle controller receiving the detected PCL position signaling signal; the autothrottle controller outputting an automatic output command signaling based on the control target setting, the automatic output command signaling including synthesizing an electrical characteristic of the detected PCL position signaling such that the automatic output command signaling is recognizable by the FADEC system as the detected PCL position signaling; and under control of the autothrottle controller, electrically selecting a throttle command signal to be connected to the command input from among the detected PCL position signaling and the automatic output command signaling.

[0103] In example 12, the subject matter of example 11 includes the step of electrically selecting includes the step of defaulting to select the sensed PCL position signal when the autothrottle control program is not engaged for autothrottle control.

[0104] In Example 13, the subject matter of Examples 11-12 includes further including generating a sensed PCL position signaling by an angular position sensor arranged to detect an angular position of the manual movable control.

[0105] In example 14, the subject matter of example 13 includes the angular position sensor receiving the excitation signal from the FADEC system and the autothrottle control device receiving the excitation signal.

[0106] In example fifteen, the subject matter of examples eleven-fourteen includes where the step of outputting the automatic output command signaling includes the step of automatically adjusting the automatic output command signaling by an autothrottle control device in accordance with an autothrottle control program independent of the manual throttle setting.

[0107] In Example 16, the subject matter of Examples 11-15 includes where the step of receiving the detected PCL location signaling includes receiving the same detected PCL location signaling as received by the FADEC system.

[0108] In example 17, the subject matter of examples 11-16 includes the autothrottle control further including learning electrical characteristics of the sensed PCL position signaling during configuration of the autothrottle control for the aircraft.

[0109] In example 18, the subject matter of examples 11-17 further includes generating an autothrottle engage signal when the autothrottle control program is in an engagement state for autothrottle control; and selecting among the sensed PCL position signaling and the automatic output command signaling to be connected to the command input is performed in response to the autothrottle engage signal.

[0110] In example 19, the subject matter of examples 11-18 includes the further step of transitioning the autothrottle control program out of an engaged state for autothrottle control in response to a detected change in the manual throttle setting based on the detected PCL position signaling.

[0111] Example 20 is at least one non-transitory machine-readable medium including instructions that, when executed by a processing circuit, cause the processing circuit to perform operations to implement any of Examples 11 to 19.

[0112] Example 21 is an apparatus comprising means for carrying out any of Examples 11 to 19.

[0113] Example 22 is a system comprising means for carrying out any one of Examples 11 to 19.

[0114] The above embodiments are intended to be illustrative and non-limiting. Additional embodiments are within each claim that does not explicitly exclude such subject matter. In addition, although aspects of the invention are described with reference to specific embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the scope of the invention as defined by the claims.

[0115] Those skilled in the art will recognize that the present invention may comprise fewer features than illustrated in any individual embodiment described above. The embodiments described herein are not intended to be an exhaustive representation of the ways in which various features of the present invention can be combined. Thus, the embodiments are not mutually exclusive combinations of features; rather, the present invention may be comprised of combinations of different individual features selected from different individual embodiments, as would be understood by one skilled in the art.

[0116] Any incorporation by reference of the above references is limited so that no subject matter contrary to the express disclosure of this specification is incorporated. Any incorporation by reference of the above references is further limited so that the claims contained in the references are not incorporated by reference into the claims of this application. However, the claims of any reference are incorporated as part of the disclosure of this specification unless specifically excluded. Any incorporation by reference of the above references is further limited so that any definitions provided in the references apply only to the incorporated subject matter and not to any subject matter directly present in this specification.

[0117] For purposes of interpreting the claims of this invention, it is expressly intended that the provisions of 35 U.S.C. §112(f) not be applied unless the specific words "means for" or "step for" appear in a claim.

Claims

1. 1. A system for controlling autothrottles on an aircraft having a Fully Automatic Digital Engine Control (FADEC) system having a command input that receives sensed power control input (PCL) position signaling indicative of a manual throttle setting, comprising: an autothrottle controller including processing circuitry, memory, and input / output mechanisms operable to execute instructions comprising an autothrottle control program, including an input operable to receive a sensed PCL position signaling, and operable to output an automatic output command signaling; a FADEC interface electrically connected to the autothrottle controller and to the FADEC system, the FADEC interface controllable by the autothrottle controller to select between the sensed PCL position signaling and the automatic output command signaling to be connected to the command input; Equipped with the autothrottle control program, when executed, causes the autothrottle controller to determine a control target setpoint and generate the automatic output command signaling in accordance with the control target setpoint when the system is in an engaged state for autothrottle control; the automatic output command signaling is generated by the autothrottle controller in accordance with the autothrottle control program and is synthesized to virtualize electrical characteristics of the sensed PCL position signaling such that the automatic output command signaling is recognizable by the FADEC system as a sensed PCL position signaling.

2. 2. The system of claim 1, wherein the FADEC interface includes an electrical selector switch that defaults to selecting the sensed PCL position signaling when the system is not engaged for autothrottle control.

3. 3. The system of claim 2, wherein the autothrottle control and the FADEC interface are configured for safe failure, and the electrical selector switch selects the automatic output command signaling only when the autothrottle control is fully functional and engaged.

4. The system of claim 1 , wherein the sensed PCL position signaling is generated by an angular position sensor positioned to detect the angular position of a manually movable lever.

5. 5. The system of claim 4, wherein the angular position sensor is operative to receive an excitation signal from the FADEC system, the excitation signal also being received by the autothrottle control device.

6. 2. The system of claim 1, wherein the automatic output command signaling is generated and automatically adjusted by the autothrottle controller in accordance with the autothrottle control program, independent of the manual throttle setting.

7. 2. The system of claim 1, wherein the input of the autothrottle control device operative to receive a sensed PCL position signaling receives the same sensed PCL position signaling as received by the FADEC system.

8. 10. The system of claim 1, wherein the autothrottle controller is operable to execute instructions including a FADEC interface process that, when executed, causes the autothrottle controller to learn electrical characteristics of the sensed PCL position signaling during configuration of the autothrottle controller for the aircraft.

9. 2. The system of claim 1, wherein the autothrottle control device is operable to generate an autothrottle engagement signal when the system is in an engagement state for autothrottle control, and the FADEC interface is operable in response to the autothrottle engagement signal to select from the sensed PCL position signaling and the automatic output command signaling to be connected to the command input.

10. 2. The system of claim 1, wherein the autothrottle control device is operable to transition out of engagement for autothrottle control in response to a detected change in manual throttle setting based on the detected PCL position signaling.

11. 1. A method for controlling autothrottles on an aircraft having a Fully Automatic Digital Engine Control (FADEC) system having a command input that receives sensed power control input (PCL) position signaling indicative of a manual throttle setting, comprising: an autothrottle controller executing instructions comprising an autothrottle control program, the autothrottle controller including determining a control target set point; receiving a sensed PCL position signaling signal by the autothrottle controller; the autothrottle controller outputting an automatic power command signal based on the control target setpoint, the automatic power command signal including synthesizing an electrical characteristic of the sensed PCL position signal such that the automatic power command signal is recognizable by the FADEC system as a sensed PCL position signal; electronically selecting, under control of the autothrottle controller, a throttle command signal to be connected to the command input from among the sensed PCL position signaling and the automatic output command signaling; A method comprising:

12. 12. The method of claim 11, wherein the step of electrically selecting includes the step of defaulting to selecting the sensed PCL position signal when the autothrottle control program is not engaged for autothrottle control.

13. The method of claim 11 , further comprising generating the sensed PCL position signaling by an angular position sensor positioned to detect an angular position of a manually movable control.

14. the angular position sensor receiving an excitation signal from the FADEC system; the autothrottle controller receiving the excitation signal; 14. The method of claim 13, further comprising:

15. 12. The method of claim 11, wherein outputting the automatic output command signaling comprises automatically adjusting the automatic output command signaling by the autothrottle controller in accordance with the autothrottle control program independent of the manual throttle setting.

16. The method of claim 11 , wherein receiving the detected PCL position signaling comprises receiving the same detected PCL position signaling as received by the FADEC system.

17. 12. The method of claim 11, further comprising the step of the autothrottle control device learning the electrical characteristics of the sensed PCL position signaling during configuration of the autothrottle control device for the aircraft.

18. further comprising the step of generating an autothrottle engagement signal when the autothrottle control program is in an engagement state for autothrottle control; 12. The method of claim 11, wherein selecting one of the sensed PCL position signaling and the automatic output command signaling to be connected to the command input is performed in response to the autothrottle engagement signal.

19. 12. The method of claim 11, further comprising transitioning the autothrottle control program out of an engaged state for autothrottle control in response to a detected change in manual throttle setting based on the detected PCL position signaling.

20. 20. At least one non-transitory machine-readable medium comprising instructions that, when executed by a processing circuit, cause the processing circuit to perform operations to implement the method of any one of claims 11 to 19.

21. A system comprising means for carrying out a method according to any one of claims 11 to 19.

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