Turbine shaft load control using feedforward and feedback control

Abstract

A control scheme is provided for controlling a gas turbine engine in response to disturbances associated with a load mechanically coupled to the gas turbine engine. In one aspect, the gas turbine engine mechanically coupled to the load has a controller that includes executable control logic. The control logic includes a feedforward module, an active control module, and a power turbine regulator module. By executing these modules, the controller attempts to stably and subtly maintain a constant power turbine speed in response to small disturbances associated with the load, and actively in response to large disturbances associated with the load, as well as through a smooth transition between responses.

Description

[0001] Federal government-funded research

[0002] This invention was completed with government support under license number W58RGZ-16-C-0047 granted by the U.S. Army. The government holds certain rights to this invention. Technical Field

[0003] This topic generally involves controlling the fuel flow requirements of gas turbine engines. Background Technology

[0004] Some gas turbine engines consist of a gas generator compressor, a combustor, a gas generator turbine, and a power turbine connected in a series flow path. The combustor generates combustion gases, which are then directed to the gas generator turbine, where they are expanded to drive the turbine. The combustion gases are then directed to the power turbine, where they are further expanded to drive the turbine. The gas generator turbine is coupled to the gas generator compressor via a gas generator shaft, and the power turbine is coupled to an output shaft via a power turbine shaft. The output shaft can be coupled to a load, such as the main rotor of a helicopter.

[0005] Gas turbine engines typically include an engine controller to determine the amount of fuel (e.g., fuel flow demand) required by the gas turbine engine to produce the desired power. In operation, the engine controller can execute control logic to output a fuel flow demand that can be used to control the fuel flow to the engine. The desired output of the load can be achieved by controlling the fuel flow to the engine. Improved engine control in response to disturbances or variations in the desired power from loads coupled to the engine is desirable in the art. Attached Figure Description

[0006] The complete and feasible disclosure of this subject matter, including its best mode, is set forth in the specification with reference to the accompanying drawings, wherein:

[0007] Figure 1 This is a perspective view of an aircraft according to an embodiment of the present disclosure;

[0008] Figure 2 This is a schematic cross-sectional view of a gas turbine engine according to an embodiment of the present disclosure;

[0009] Figure 3 This is a logic diagram depicting the turbine shaft speed control logic according to an embodiment of the present disclosure;

[0010] Figure 4 It is a graph showing the fuel flow rate as a function of system error according to an embodiment of the present disclosure;

[0011] Figure 5 This is a logic diagram depicting another structure of the turbine shaft speed control logic according to an embodiment of the present disclosure;

[0012] Figure 6 This is a flowchart of an example method according to an example embodiment of the present disclosure;

[0013] Figure 7 Schematic diagrams of computing systems for implementing one or more aspects of this disclosure are provided according to exemplary embodiments thereof; and

[0014] Figure 8 An example carrier is provided according to an example embodiment of the present disclosure. Detailed Implementation

[0015] Reference will now be made in detail to current embodiments of the subject matter, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation and not limitation of the subject matter. Indeed, it will be apparent to those skilled in the art that modifications and variations can be made to the subject matter without departing from its scope. For example, features shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, the subject matter is intended to cover such modifications and variations that fall within the scope of any claims and their equivalents.

[0016] The detailed description uses numbers and letters to refer to features in the accompanying drawings. Similar or analogous reference numerals in the drawings and description have been used to refer to similar or related parts of the subject matter, and the same numbers indicate the same elements throughout the drawings. As used herein, the terms "first," "second," and "third" are used interchangeably to distinguish one component from another and are not intended to indicate the position or relative importance of the individual components.

[0017] The terms "upstream" and "downstream" refer to the relative directions of fluid flow within a fluid path. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction from which the fluid flows.

[0018] Unless otherwise stated herein, the terms “connection,” “fixed,” “attached to,” etc., refer to both direct connection, fixation, or attachment, and indirect connection, fixation, or attachment via one or more intermediate components or features.

[0019] Unless the context clearly indicates otherwise, the singular forms “a,” “a,” and “the” include plural references.

[0020] As used throughout this specification and claims, approximate language is applied to modify any quantitative expression that may allow for variation without altering its underlying function. Therefore, values ​​modified by terms such as “about,” “approximately,” and “substantially” are not limited to specified exact values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value, or the precision of the method or machine used to construct or manufacture the component and / or system. For example, approximate language may refer to a margin of 2%, 5%, 10%, or 20%.

[0021] Throughout this specification and claims, scope limitations are combined and interchanged, and unless the context or language otherwise indicates otherwise, such scopes are identified and include all subscopes contained herein. For example, all scopes disclosed herein include endpoints, and endpoints may be combined independently of each other.

[0022] This disclosure generally relates to using feedforward and feedback control to control fuel flow to a gas turbine engine in response to disturbances associated with loads mechanically coupled to the gas turbine engine. Specifically, control logic is provided that seeks to stably and subtly maintain a constant power turbine speed in response to relatively small disturbances associated with the load, and aggressively in response to relatively large disturbances associated with the load, with a smooth transition between responses.

[0023] In one example aspect, a gas turbine engine is provided that is mechanically coupled to a load of an aircraft. For example, the gas turbine engine may be a turboshaft engine, and the load may be the main rotor of a helicopter. The gas turbine engine may include a controller having one or more processors configured to perform various operations, including turbine shaft speed control logic, to maintain a constant speed of the power turbine of the gas turbine engine despite disturbances associated with the rotor. The turbine shaft speed control logic includes a feedforward regulation module and a feedback regulation module.

[0024] The feedforward regulation module includes a feedforward module that converts the aircraft input rate into a first fuel flow demand. For example, the aircraft input rate may correspond to the rate of change of the pitch angle of the helicopter's main rotor in response to manipulation by a common control unit. The feedforward module can be rate-independent, which allows for rapid initial acceleration. The feedback regulation module includes an active control module and a power turbine regulator module. The power turbine regulator module converts the power turbine speed error into a third fuel flow demand, while the active control module calculates the system error based on the power turbine speed error, the power turbine speed error rate derived from the power turbine speed error, and the bandwidth of one or more processors executing the feedback regulation module. The active control module converts the system error into a second fuel flow demand. Typically, the active control module is configured to apply a rapid and forceful "kick" when there is a relatively large disturbance in the rotor load (e.g., a relatively large increase or decrease in required lift).

[0025] The first, second, and third fuel flow requirements are summed to determine the composite fuel flow requirement. The fuel flow to the gas turbine engine can then be controlled based on this composite fuel flow requirement. Ultimately, the feedforward and feedback regulation modules together allow the power turbine to respond to relatively small disturbances in rotor loads and actively respond to relatively large disturbances in rotor loads to stably maintain a constant speed. The turbine shaft control logic integrates these two objectives into a cohesive control scheme.

[0026] The turbine shaft speed control logic disclosed herein offers numerous technical effects, advantages, and benefits. For example, as mentioned above, the feedforward module of this disclosure may not require rate limiting. Furthermore, the feedforward module of this disclosure utilizes the rate of change of the aircraft input instead of the direct input, which simplifies the physical modeling of the rotor system to the estimation of partial derivatives rather than precise calculations. This simplifies processing time and frees up processing resources. Additionally, the feedback regulation module of this disclosure allows for stable regulation via the power turbine regulator module in response to relatively small rotor load disturbances, and rapid and powerful stable regulation via the active control module in response to relatively large rotor load disturbances. Since the "backlash" provided by the active control module is not filtered by the power turbine regulator module, a smooth transition to or from active control is possible. It should be understood that, in addition to those explicitly stated herein, the inventive aspects of this disclosure can offer other benefits and advantages.

[0027] Now turn to the attached diagram. Figure 1 A perspective view of an aircraft 10 according to an example embodiment of the present disclosure is provided. Figure 1In this design, aircraft 10 is a rotorcraft, and more specifically, a helicopter. Aircraft 10 defines an orthogonal coordinate system comprising three orthogonal axes. More specifically, the three orthogonal coordinate axes include a lateral axis L, a longitudinal axis T, and a vertical axis V. In operation, aircraft 10 can move along or around at least one of the lateral axis L, the longitudinal axis T, and the vertical axis V.

[0028] exist Figure 1 In the illustrated embodiment, the aircraft 10 includes a fuselage 12 defining a cockpit 20. Among other things, the cockpit 20 includes a common pitch input 22, a cyclic pitch input 23, a tail rotor input 24, a first throttle input 26, a second throttle input 28, and an instrument panel 30. The aircraft 10 also includes a main rotor assembly 40 and a tail rotor assembly 50. The main rotor assembly 40 includes a main rotor hub 42 and a plurality of main rotor blades 44. As shown, each main rotor blade 44 extends outward from the main rotor hub 42. The tail rotor section 50 includes a tail rotor hub 52 and a plurality of tail rotor blades 54. Each tail rotor blade 54 extends outward from the tail rotor hub 52.

[0029] Furthermore, the aircraft 10 includes a first gas turbine engine 60 and a second gas turbine engine 62. The first and second gas turbine engines 60 and 62 generate and transmit power to drive the rotation of the main rotor blade 44 and the tail rotor blade 54. The rotation of the main rotor blade 44 generates lift for the aircraft 10, while the rotation of the tail rotor blade 54 generates lateral thrust in the tail rotor section 50 and counteracts the torque exerted on the fuselage 12 by the main rotor blade 44.

[0030] The common pitch input device 22 collectively (i.e., simultaneously) adjusts the pitch angle of the main rotor blades 44 to increase or decrease the lift obtained by the aircraft 10 from the main rotor blades 44 at a given rotor speed. More specifically, manipulating the common pitch input device 22 causes the aircraft 10 to move in one of two opposing directions along the vertical direction V, or in other cases, to maintain a hovering maneuver. Manipulating the common pitch input device 22 can also be used to predict the amount of power supplied by the first and second gas turbine engines 60, 62 to the main rotor assembly 40 to generate the desired lift for the aircraft 10. The common pitch input device 22 may include an input device 32 configured to set reference speeds for the first and second gas turbine engines 60, 62. In one exemplary embodiment, the input device 32 may be a switch configured to set reference speeds for both the first and second gas turbine engines 60, 62.

[0031] The cyclic pitch input device 23 controls the movement of the aircraft 10 about the longitudinal axis T and about the lateral axis L. Specifically, the cyclic pitch input device 23 adjusts the angle of the aircraft 10, thereby allowing the aircraft 10 to move forward or backward in the longitudinal direction T or laterally in the lateral direction L. Additionally, the tail rotor input device 24 controls the pitch angle of the tail rotor blades 54. In operation, manipulating the tail rotor input device 24 causes the tail rotor section 50 to move in the lateral direction L, which changes the orientation of the aircraft 10.

[0032] The first and second throttle input devices 26, 28 can be moved to the open position at the start of flight and remain in the open position during flight. For example, the first and second throttle input devices 26, 28 can be moved to the FLY position at the start of flight and can remain in that position throughout the flight. In some cases, the first and / or second throttle input devices 26, 28 can be moved to different positions.

[0033] Although aircraft 10 is shown and described herein as having a main / tail rotor configuration, it should be understood that the teachings of this disclosure can be applied more generally to other types of aircraft and launch vehicles (see...). Figure 8 For example, aircraft 10 can be any aircraft or carrier, including but not limited to coaxial rotor helicopters, tandem rotor helicopters, parallel rotor helicopters, twin-rotor helicopters, tiltrotor aircraft, unmanned aerial vehicles (UAVs) of unmanned aerial vehicle systems (UAS), fixed-wing aircraft, amphibious vehicles, hovercraft, land vehicles, and other turbine-driven carriers.

[0034] Figure 2 A schematic cross-sectional view of an exemplary gas turbine engine 100 according to one embodiment of the present disclosure is provided. Figure 2 As shown, a gas turbine engine 100 defines a longitudinal or centerline axis 102 extending through it for reference. The gas turbine engine 100 typically includes a generally tubular housing 104 defining an annular inlet 106. The housing 104 may be formed of a single housing or multiple housings. The housing 104 surrounds a gas generator compressor 110, a combustion section 130, a turbine section 140, and an exhaust section 150 in a series flow relationship. The gas generator compressor 110 includes an annular array of inlet guide vanes 112, one or more sequential stages of compressor blades 114, one or more sequential stages of stationary and / or variable guide vanes 116, and a centrifugal compressor 118. The compressor blades 114, vanes 116, and centrifugal compressor 118 collectively define a compressed air path 120.

[0035] Combustion section 130 includes a burner defining a combustion chamber 132 and one or more fuel nozzles 134 extending into the combustion chamber 132. The fuel nozzles 134 supply fuel to mix with compressed air entering the combustion chamber 132. The fuel and compressed air mixture is burned within the combustion chamber 132 to form combustion gas 136. As will be described in more detail below, the combustion gas 136 drives a turbine 140, which in turn drives a gas generator compressor 110.

[0036] Turbine section 140 includes a gas generator turbine 142 and a power turbine 144. The gas generator turbine 142 includes one or more sequential stages of turbine rotor blades 146 and one or more sequential stages of stator blades 147. Similarly, the power turbine 144 includes one or more sequential stages of turbine rotor blades 148 and one or more sequential stages of stator blades 149. Furthermore, the gas generator turbine 142 drives the gas generator compressor 110 via a gas generator shaft 160, and the power turbine 144 drives the output shaft 180 via a power turbine shaft 170.

[0037] More specifically, such as Figure 2 As shown in the embodiment, the gas generator compressor 110 and the gas generator turbine 142 are connected to each other via a gas generator shaft 160, and the power turbine 144 and the output shaft 180 are connected to each other via a power turbine shaft 170. In operation, combustion gas 136 drives the gas generator turbine 142 and the power turbine 144. As the gas generator turbine 142 rotates about a centerline axis 102, the gas generator compressor 110 and the gas generator shaft 160 also rotate about the centerline axis 102. Furthermore, as the power turbine 144 rotates, the power turbine shaft 170 rotates and transfers rotational energy to the output shaft 180. As an example, the gas turbine engine 100 may be... Figure 1 The first and second gas turbine engines 60 and 62, and the output shaft 180 can rotate the main rotor blade 44 and the tail rotor blade 54 of the aircraft 10.

[0038] Still referencing Figure 2 The gas turbine engine 100 also includes a first sensor 190 and a second sensor 192. In one embodiment, the first sensor 190 may be configured to sense the rotational speed N of the power turbine shaft 170. P The information. However, in an alternative embodiment, the first sensor 190 may be configured to sense the rotational speed N of the output shaft 180. R The second sensor 192 can be configured as at least one of a pressure sensor or a temperature sensor. For example, in an exemplary embodiment, the second sensor 192 can be a temperature sensor configured to sense the turbine gas temperature T of the gas turbine engine 100.4.5 Information. Alternatively or otherwise, the second sensor 192 may be a pressure sensor configured to sense the compressor discharge pressure P of the gas turbine engine 100. S3 Information.

[0039] Now for a brief reference Figure 1 and Figure 2 It should be understood that, in at least some exemplary embodiments, Figure 1 One or both of the first and second gas turbine engines 60, 62 of the aircraft 10 can be coupled with Figure 2 The gas turbine engine 100 depicted is constructed in a substantially similar manner. Furthermore, the first and second gas turbine engines 60 and 62 can be mechanically coupled to each other, allowing them to operate together. For example, the first and second gas turbine engines 60 and 62 can be joined together in a gearbox via, for example, a differential and a one-way clutch (e.g., a wedge clutch), enabling them to operate together.

[0040] However, it should be understood that in other exemplary embodiments, Figure 2 The gas turbine engine may alternatively have any other suitable configuration. For example, in other exemplary embodiments, combustion section 130 may include a counter-current burner. Furthermore, in other exemplary embodiments, the gas turbine engine 100 may not be configured as a dual-shaft machine, but may include a common shaft configured to connect the compressor, turbine, and output shaft.

[0041] like Figure 2As schematically shown, a gas turbine engine 100 may include a controller 200. Typically, the controller 200 may correspond to any suitable processor-based device. For example, the controller 200 may include one or more processors and one or more memory devices. The one or more processors may be configured to perform a variety of computer-implemented functions (e.g., perform the operations disclosed herein, etc.). As used herein, the term "processor" refers not only to an integrated circuit as known in the art as included in a computer, but also to a controller, microcontroller, microcomputer, programmable logic controller (PLC), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), and other programmable circuits. Furthermore, the one or more memory devices may include a variety of memory elements, including but not limited to computer-readable media (e.g., random access memory (RAM)), computer-readable non-volatile media (e.g., flash memory), optical disc read-only memory (CD-ROM), magneto-optical disc (MOD), digital versatile disc (DVD), and / or other suitable memory elements, or combinations thereof. Memory 208 may store computer-executable instructions that, when executed by the one or more processors, cause the one or more processors to operate. For example, the controller 200 may be an electronic engine controller (EEC) or a digital engine controller (DEC). Controller 200 may be part of a Full Authority Digital Engine Control (FADEC) system. Furthermore, among other devices and components, controller 200 may be communicatively connected via one or more wired and / or wireless connections to one or more input devices within cockpit 20, one or more controllable devices on gas turbine engine 100, and one or more sensors (e.g., sensors 190, 192). The one or more controllable devices within gas turbine engine 100 may include, but are not limited to, fuel metering or control valves, fuel pumps, other fuel control units, variable geometry elements, etc. Among other devices, input devices may include, but are not limited to, common pitch input device 22, circulating pitch input device 23, tail rotor input device 24, first throttle input device 26, second throttle input device 28, and instrument panel 30.

[0042] Figure 3 A control logic diagram according to an example embodiment of this disclosure is provided. Specifically, Figure 3 The control logic diagram depicts the turbine shaft speed control logic 300, which, when executed by one or more processors, attempts to stably maintain a constant power turbine speed in response to both small disturbances in the rotor load and large disturbances in the rotor load. The turbine shaft speed control logic 300 integrates these two objectives into a cohesive control scheme. Typically, the turbine shaft speed control logic 300 will refer to the above reference... Figure 1 and Figure 2The aircraft 10 and gas turbine engine 100 are described in this context. However, in other embodiments, the turbine shaft speed control logic 300 may be implemented or used in association with any other aircraft and / or suitable gas turbine engine.

[0043] The turbine shaft speed control logic 300 includes a feedforward adjustment module 302 and a feedback adjustment module 304. For example... Figure 3 As shown, the turbine shaft speed control logic 300 includes a feedforward module 310, an active control module 320, and a power turbine regulator module 330. The feedforward module 310 is a component of the feedforward regulation module 302, while the active control module 320 and the power turbine regulator module 330 are components of the feedback regulation module 304. In this embodiment, the active control module 320 and the power turbine regulator module 330 are independent modules and are arranged in parallel with each other in the feedback regulation module 304.

[0044] Regarding the feedforward adjustment module 302, the feedforward module 310, during execution, uses one or more physical models 312 of the rotor system of the aircraft 10 to convert the rate of change of the aircraft input into a first fuel flow demand. In other words, one or more processors can execute the feedforward module 310 at least in part based on the rotor system of the aircraft 10 (e.g., Figure 1 The power demand rate associated with the main rotor of the aircraft 10 (40) Determine the first fuel flow requirement The first fuel flow demand output from the feedforward module 310 The user is directed to the summation box 340.

[0045] Typically, the feedforward module 310 is tuned to ensure that the initial fuel flow demand from its output does not force the engine to accelerate or decelerate in the wrong direction. Furthermore, the feedforward module 310 is tuned for the rotor system without considering engine capabilities, allowing for the specific specification and tuning of the aircraft's handling qualities. Additionally, the feedforward module 310 is not rate-limited, which ultimately allows for rapid initial acceleration or deceleration of the rotor system. Moreover, using the rate of change of the aircraft inputs instead of direct inputs reduces the physical modeling of the rotor system to estimates of partial derivatives rather than exact calculations.

[0046] The rate of change of the aircraft input can be derived from operator control via an operator-operated input device (located on or at a remote guidance station outside the aircraft 10). For example, the operator-operated input device could be... Figure 1At least one of the common pitch input device 22, the cyclic pitch input device 23, and the tail rotor input device 24 depicted herein. Additionally or alternatively, the rate of change of the aircraft input can be derived from an automatic flight system that controls the power requirements associated with the rotor system of the aircraft 10.

[0047] In one example embodiment, the operator-operated input device may be Figure 1 The common pitch input device 22. Therefore, in a first time step, in response to the manipulation of the common pitch input device 22, the common pitch input device 22 or other sensors on the aircraft 10 can be configured to generate a first signal, for example, indicating an increase or decrease in the vertical lift demand of the aircraft 10. Then, in a second time step, in response to the manipulation of the common pitch input device 22, the common pitch input device 22 or other sensors on the aircraft 10 can be configured to generate a second signal, for example, indicating an increase or decrease in the vertical lift demand of the aircraft 10. As will be understood, based on the first and second signals, the power demand rate associated with the main rotor 40...

[0048] Regarding the feedback adjustment module 304, the power turbine adjuster module 330 will adjust the power turbine speed error N during execution. p Error is converted into third fuel flow demand. Power turbine speed error N p Error indicates the speed error between the reference speed and the actual speed of the power turbine 144. When executed, the power turbine regulator module 330 can, for example, use one or more models, lookup tables, combinations thereof, etc., to calculate the power turbine speed error N. p Error is converted into third fuel flow demand. Third fuel flow demand output from power turbo conditioner module 330 The user is directed to the summation box 340.

[0049] The active control module 320 also utilizes the power turbine speed error N during execution. p Error. Specifically, when executed, the active control module 320 is at least partially based on the power turbine speed error N. p Error, power turbine speed error rate The system error s is calculated by relating it to the bandwidth λ of one or more processors executing the active control module 320. Specifically, the system error s is defined by the following equation:

[0050]

[0051] Where s is the system error and NpError is the power turbine speed error. λ is the power turbine speed error rate, and λ is the bandwidth of one or more processors executing the active control module 320. When executed, the active control module 320 translates the system error s into a second fuel flow demand. In this way, the second fuel flow requirement is determined, at least in part, based on a defined systematic error s. The second fuel flow demand output from the active control module 320 The user is directed to the summation box 340.

[0052] The execution of the active control module 320 will now be described in more detail. For example... Figure 3 As shown, N p Error is input into the active control module 320. As noted, the power turbine speed error N p Error indicates the speed error between the reference speed and the actual speed of the power turbine 144. Power turbine speed error rate. From the power turbine speed error N p Error export. For example, the power turbine speed error N at the first time step. p Error and the second time step power turbine speed error N p Error can be used to derive the rate of change of power turbine speed error or the power turbine speed error rate. The second time step occurs later than the first time step. The bandwidth λ of one or more processors executing the active control module 320 is set to dampen the drivetrain resonant frequency, taking into account the bandwidth capability of the power turbine regulator module 330.

[0053] In calculating or knowing the power turbine speed error N p Error, power turbine speed error rate Given the bandwidth λ of one or more processors executing the active control module 320, the system error s can be determined by one or more processors executing the active control module 320. For example... Figure 4 As shown, the second fuel flow demand It can be arranged as a function of the systematic error s.

[0054] As depicted, the active control module 320 includes a deadband φ, which indicates the second fuel demand. The systematic error range or systematic error band determined to be zero. In other words, the dead band φ indicates the systematic error band, and the second fuel demand is determined when the systematic error s is within this systematic error band. It is determined to be zero or approximately zero. For example... Figure 4As shown, the dead zone φ ranges between the first limit -φ and the second limit +φ. It is worth noting that when the system error s is determined to be within the dead zone φ, the second fuel demand... The system error s is set to zero. At this point, when the system error s is determined to be within the dead zone φ, the active control module 320 is inactive. Conversely, when the system error s is determined to be outside the dead zone φ, the second fuel demand... It is determined to be non-zero. Therefore, when the system error s is determined to be outside the dead zone φ, the active control module 320 activates.

[0055] The first limit -φ and the second limit +φ of the deadband φ can be tuned so that the active control module 320 only activates when there is a large disturbance in the rotor system. For example, the system error to the left of the first limit -φ and the system error to the right of the second limit +φ correspond to a relatively large disturbance, while the system error within the deadband φ (or the system error to the right of the first limit -φ and the system error to the left of the second limit +φ) corresponds to a relatively small disturbance associated with the rotor system.

[0056] For the systematic error to the left of the first limit -φ, the second fuel demand is arranged. Corresponding to the increased fuel demand, this addresses the relatively large disturbances associated with the rotor system. For example, as an example, additional and significant lift may be required for the aircraft 10 to perform a vertical climb. Therefore, the rotor system is subjected to relatively large disturbances. Considering the required additional and significant lift, the active control module 320 reacts quickly and forcefully by applying a "recoil" to rapidly increase the fuel flow to the engine 100. Therefore, the active control module 320 outputs a second fuel demand. This corresponds to an increase in the required fuel flow rate.

[0057] For the systematic error to the right of the second limit + φ, the second fuel demand is arranged. Corresponding to the reduced fuel demand, this addresses the relatively large disturbances associated with the rotor system. For example, as an example, a significant reduction in lift may be required. Therefore, the rotor system is subjected to relatively large disturbances. Considering the required reduction in lift, the active control module 320 reacts quickly and forcefully by applying a "recoil" to rapidly reduce the fuel flow to engine 100. Therefore, the active control module 320 outputs a second fuel demand. This corresponds to a reduction in the required fuel flow rate.

[0058] Because the active control module 320 is only activated when a relatively large system error exists, it does not need to maintain the same stability requirements as the power turbine regulator module 330, nor does it need to decay the modes in the rotor system. Therefore, as noted, the active control module 320 can react faster and more forcefully than the gain kicker of a conventional power turbine regulator.

[0059] Furthermore, the deadband φ, or more precisely, the first limit -φ and the second limit +φ of the deadband φ, can be tuned to manage the transition between the stable power turbo tuner module 330 and the active control module 320 to obtain optimal or otherwise improved system response. This allows for a smooth transition between the output of the feedback regulation module 304 being regulated using the power turbo tuner module 330 when the system error s is relatively small and being regulated using the backlash of the active control module 320 in addition to the power turbo tuner module 330 when the system error s is relatively large. The deadband φ can be automatically tuned, for example, through an automatic tuning loop, or it can be manually tuned. Generally, the larger the deadband φ, the less active the active control module 320 will be; conversely, the smaller the deadband φ, the more active the active control module 320 will be.

[0060] like Figure 4 The description in the text relates to the third fuel flow demand. The associated arrangement is shown as a function of the system error s to illustrate the difference in how the feedback control module 304 responds to small disturbances compared to large disturbances. It is noteworthy that this is related to the third fuel flow demand. The slope ratio of the associated arrangement with the second fuel flow demand The slope of the non-dead-band portion of the associated arrangement is smaller or less steep. At this point, when the system error s is relatively small, the power turbocharger regulator module 330 reacts in a relatively conservative manner, increasing or decreasing fuel flow, while the active control module 320 remains inactive. In fact, when the system error s is within the dead-band φ, it corresponds to the synthesized feedback fuel flow demand. The feedback arrangement is directly along with the third fuel flow demand. Related scheduling tracking. Feedback on synthetic fuel flow demand. The associated feedback arrangement represents the second fuel flow demand. and third fuel flow demand The combination of related arrangements. When, for example, the system error s is transitioned from a small disturbance to a large disturbance by determining that the system error s is not within the dead zone φ, compared with the gain recoil of a conventional power turbine regulator module, the synthetic feedback fuel flow demand... The associated feedback arrangement transitions relatively smoothly to incorporating "recoil" from the active control module 320. The relative gain of the active control module 320 is set to smoothly transition between active and non-active control.

[0061] Refer again Figure 3 One or more processors can determine the synthetic fuel flow requirements. Specifically, one or more processors may be based at least in part on the first fuel flow requirement. Second fuel flow demand and third fuel flow demand To determine the fuel flow requirements for synthesis. To determine the fuel flow requirements for synthesis One or more processors can execute summation box 340 to calculate the first fuel flow requirement. Second fuel flow demand and third fuel flow demand Summation. Thus, the synthetic fuel flow rate requirement. It could be the first fuel flow requirement. Second fuel flow demand and third fuel flow demand The sum of . From the above teachings, it can be understood that when the systematic error s is within the dead zone φ, the second fuel flow demand . The second fuel flow rate requirement is zero when the system error s is not within the dead zone φ. Not equal to zero, therefore, the active control module 320 provides "recoil" to respond quickly and forcefully to large disturbances associated with the rotor system. As will be understood, one or more processors can, for example, control one or more controllable devices, at least in part, based on the synthesized fuel flow demand. To control the fuel flow to the gas turbine engine 100, the one or more controllable devices, when actuated, cause more or less fuel to be supplied to the gas turbine engine 100 or its combustor.

[0062] It should be understood that Figure 3 The turbine shaft speed control logic 300 described herein can be constructed in different ways, but it can still provide the advantages and benefits disclosed herein. For example, Figure 5 An alternative architecture for the turbine shaft speed control logic 300 is described. Figure 5 In the middle, the second fuel flow demand comes from the active control module 320. and the third fuel flow demand from the power turbine regulator 330 Summation can be performed at point 342 in the summation box to present feedback on fuel flow demand. Then, the feedback fuel flow demand can be... The input is directed to summation box 340, where the fuel flow demand is fed back. First fuel flow demand from feedforward module 310 Summation. It should be understood that... Figure 5 Depicting Figure 3 This is an example alternative to the construction of the turbine shaft speed control logic 300, and other alternatives are possible.

[0063] Figure 6 A flowchart of an example method 600 for controlling the fuel flow to a gas turbine engine in response to disturbances associated with a rotor mechanically coupled to the gas turbine engine is provided. Figure 6 Method 600 can be implemented using, for example, the controller 200 and other components described herein. In some embodiments, the gas turbine engine can be... Figure 2 The turbine shaft gas turbine engine 100, and the rotor can be Figure 1 The main rotor of the aircraft carrier is 40. For illustrative and discussion purposes, Figure 6 Actions performed in a specific sequence are described. Those skilled in the art who use the disclosure provided herein will understand that various actions of method 600 can be modified in various ways without departing from the scope of this disclosure.

[0064] At 602, method 600 includes determining a first fuel flow demand, at least in part, based on a power demand rate associated with a rotor of an aircraft mechanically coupled to a gas turbine engine having a power turbine, by executing one or more processors of a feedforward module. For example, the power demand rate could be a pitch change rate associated with the blades of the aircraft's main rotor. For example, the change rate could be determined in response to manipulation of a common pitch input device from a first time step to a second time step.

[0065] At 604, method 600 includes determining a second fuel flow demand by one or more processors executing an active control module, based at least in part on a power turbine speed error associated with the power turbine and a power turbine speed error rate derived from the power turbine speed error. In some embodiments, determining at 604 includes calculating a system error associated with the rotor by one or more processors based at least in part on a relationship between the power turbine speed error, the power turbine speed error rate, and the bandwidth of one or more processors executing the active control module. In such embodiments, the second fuel flow demand is determined at least in part based on the system error. For example, the second fuel flow demand may be arranged as a function of the system error, such as... Figure 4As shown. The second fuel flow demand can be arranged as a function of the system error so that the "backlash" provided by the active control module can be proportional to the magnitude of the disturbance. In this way, very large backlashes can be applied to very large disturbances, while relatively small backlashes can be applied to relatively small disturbances. As noted, for small disturbances, such as those caused by the arranged deadband, the active control module may not provide any backlash at all, thus allowing feedback regulation control to be handled by the power turbine regulator module. The system error can be defined according to Equation 1 disclosed herein.

[0066] Furthermore, in some embodiments, the active control module includes a dead band indicating the system error band, wherein the second fuel flow demand is determined to be zero when the system error is within the dead band, and non-zero when the system error is outside the dead band. The dead band may be defined by a first limit (e.g., a negative system limit) and a second limit (e.g., a positive system limit). The first and second limits can be dynamically tuned or adjusted, for example, to manage the transition between the stable response provided by the power turbine regulator and the active control module, thereby achieving optimal system response.

[0067] At 606, method 600 includes determining a third fuel flow demand, at least in part, based on a power turbine speed error, by executing one or more processors of the power turbine regulator module. For example, the power turbine speed error can be directly translated into a third fuel flow demand, for instance, using one or more models or lookup tables. The active control module and the power turbine regulator module can be modules of the feedback regulation module and can be arranged in parallel with respect to each other.

[0068] At 608, method 600 includes determining a composite fuel flow demand, at least in part based on a first fuel flow demand, a second fuel flow demand, and a third fuel flow demand, by one or more processors. For example, in some embodiments, determining the composite fuel flow demand at 608 may include summing the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand by one or more processors. The three fuel flow demands may be summed at a single summation box (e.g., in a...). Figure 3 The summation is performed at point 340 (as shown in the summation box). Therefore, the synthesized fuel flow demand is the sum of the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand.

[0069] In other embodiments, determining the synthesized fuel flow demand at 608 may include summing the second and third fuel flow demands via one or more processors to present a feedback fuel flow demand, for example, as... Figure 5The summation box 342 is depicted in the diagram. In such an implementation, method 600 may further include summing the first fuel flow demand and the feedback fuel flow demand by one or more processors, for example, as shown in the diagram. Figure 5 The summation box 340 is depicted in the middle.

[0070] At 610, method 600 includes controlling the fuel flow to the gas turbine engine by means of one or more processors, at least in part based on a synthesized fuel flow demand. For example, based on the synthesized fuel flow demand, one or more controllable devices (e.g., fuel metering valves) can be actuated or controlled to allow more or less fuel to enter the engine. In this way, the engine can better maintain a constant speed despite disturbances in the rotor load.

[0071] Figure 7 A block diagram of an example computing system 700 is provided. The computing system 700 can be used to implement the aspects disclosed herein. The computing system 700 may include one or more computing devices 702. For example, the controller 200 disclosed herein may be constructed and operated in the same or similar manner as one of the computing devices 702.

[0072] like Figure 7 As shown, one or more computing devices 702 may each include one or more processors 704 and one or more memory devices 706. The one or more processors 704 may include any suitable processing means, such as a microprocessor, microcontroller, integrated circuit, logic device, or other suitable processing means. The one or more memory devices 706 may include one or more computer-readable media, including but not limited to non-transitory computer-readable media, RAM, ROM, hard disk drives, flash drives, and other memory devices, such as one or more buffer devices.

[0073] One or more memory devices 706 may store information accessible by one or more processors 704, including computer-readable instructions 708 executable by one or more processors 704. Instructions 708 may be any set of instructions or control logic that causes one or more processors 704 to operate when executed by one or more processors 704. Instructions 708 may be software written in any suitable programming language or may be implemented in hardware. In some embodiments, instructions 708 may be executed by one or more processors 704 to cause one or more processors 704 to operate.

[0074] The memory device 706 may further store data 710 accessible by the processor 704. For example, data 710 may include sensor data (e.g., engine parameters, model data, logic data, etc. as described herein), aircraft inputs, power demand rates, etc. According to exemplary embodiments of this disclosure, data 710 may include one or more tables, functions, algorithms, models, equations, etc.

[0075] One or more computing devices 702 may also include a communication interface 712 for communicating, for example, with other components of the aircraft. The communication interface 712 may include any suitable components for interfacing with one or more networks, including, for example, a transmitter, receiver, port, controller, antenna, or other suitable components.

[0076] Figure 8 An example vehicle 800 according to an exemplary embodiment of this disclosure is provided. The inventive aspects of this disclosure can be implemented on aircraft (e.g., helicopters or fixed-wing aircraft), automobiles, ships, submarines, trains, unmanned aerial vehicles or drones, and / or any other suitable vehicle. Although this disclosure is described herein with reference to aircraft embodiments, it is intended to be illustrative only and not restrictive. Those skilled in the art will understand that the inventive aspects of this disclosure can be implemented on other vehicles without departing from the scope of this disclosure. Furthermore, aspects of the invention can be implemented for non-vehicle applications. For example, aspects of the invention can be applied to nuclear power applications, such as emergency diesel generators and turbine generators for nuclear reactors.

[0077] The technologies discussed in this paper refer to computer-based systems, actions taken by computer-based systems, information sent to computer-based systems, and information received from computer-based systems. It should be understood that the inherent flexibility of computer-based systems allows for a wide variety of possible configurations, combinations, and divisions of tasks and functions between and within components. For example, the processes discussed in this paper can be implemented using a single computing device or multiple computing devices working in combination. Databases, memory, instructions, and applications can be implemented on a single system or distributed across multiple systems.

[0078] While specific features of various embodiments may be shown in some figures but not in others, this is merely for convenience. Any feature of the figures may be referenced and / or claimed in accordance with the principles of this disclosure, in conjunction with any feature of any other figure.

[0079] This written description uses examples to disclose the subject matter, including best practices, and also enables any person skilled in the art to practice the subject matter, including making and using any device or system and methods of making any combination. The patent scope of this subject matter is defined by the claims, but may include other examples that would occur to a person skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural elements that are not indistinguishable from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

[0080] Further aspects of this disclosure are provided by the subject matter of the following clauses:

[0081] 1. A gas turbine engine, comprising: a power turbine mechanically coupled to a load; and one or more processors configured to: determine a first fuel flow demand based at least in part on a power demand rate associated with the load; determine a second fuel flow demand based at least in part on a power turbine speed error associated with the power turbine and a power turbine speed error rate derived from the power turbine speed error; determine a third fuel flow demand based at least in part on the power turbine speed error; determine a synthesized fuel flow demand based at least in part on the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand; and control the fuel flow to the gas turbine engine based at least in part on the synthesized fuel flow demand.

[0082] 2. The gas turbine engine according to any of the preceding clauses, wherein the one or more processors execute a feedforward module to determine the first fuel flow demand based at least in part on the power demand rate associated with the load.

[0083] 3. The gas turbine engine according to any of the preceding clauses, wherein the one or more processors execute a power turbine regulator module to determine the third fuel flow requirement based at least in part on the power turbine speed error.

[0084] 4. The gas turbine engine according to any of the preceding clauses, wherein the one or more processors execute an active control module to determine the second fuel flow demand based at least in part on the power turbine speed error associated with the power turbine and the power turbine speed error rate derived from the power turbine speed error.

[0085] 5. The gas turbine engine according to any of the preceding clauses, wherein, when determining the second fuel flow demand, the one or more processors are configured to: calculate a system error associated with the load based at least in part on the relationship between the power turbine speed error, the power turbine speed error rate, and the bandwidth of the one or more processors executing the active control module, and wherein the second fuel flow demand is determined based at least in part on the system error.

[0086] 6. The gas turbine engine according to any of the preceding clauses, wherein the system error is limited by the following formula: Where s is the system error, and NpError is the power turbine speed error. λ is the power turbine speed error rate, and λ is the bandwidth associated with the one or more processors executing the active control module.

[0087] 7. The gas turbine engine according to any of the preceding clauses, wherein the active control module includes a dead band indicating the system error band, wherein the second fuel flow requirement is determined to be zero when the system error is within the dead band.

[0088] 8. The gas turbine engine according to any of the preceding clauses, wherein the second fuel flow requirement is determined to be non-zero when the system error is not within the dead zone.

[0089] 9. The gas turbine engine according to any of the preceding clauses, wherein, when determining the composite fuel flow demand, the one or more processors are configured to: sum the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand, and wherein the composite fuel flow demand is the sum of the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand.

[0090] 10. The gas turbine engine according to any of the preceding clauses, wherein the active control module and the power turbine regulator module are modules of the feedback regulation module and are arranged in parallel with respect to each other.

[0091] 11. A vehicle comprising: a rotor; a gas turbine engine mechanically coupled to the rotor, the gas turbine engine including a power turbine; and one or more processors configured to: determine a first fuel flow demand based at least in part on a power demand rate associated with the rotor of the vehicle by executing a feedforward module; determine a second fuel flow demand based at least in part on a power turbine speed error associated with the power turbine, a power turbine speed error rate derived from the power turbine speed error, and the bandwidth of the one or more processors executing the active control module by executing an active control module; determine a third fuel flow demand based at least in part on the power turbine speed error by executing a power turbine regulator module; determine a synthesized fuel flow demand based at least in part on the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand; and control the fuel flow to the gas turbine engine based at least in part on the synthesized fuel flow demand.

[0092] 12. The vehicle according to any of the preceding clauses, wherein, when determining the second fuel flow requirement by executing the active control module, the one or more processors are configured to: calculate a system error associated with the rotor based at least in part on the relationship between the power turbine speed error, the power turbine speed error rate, and the bandwidth of the one or more processors executing the active control module, and wherein the second fuel flow requirement is determined based at least in part on the system error.

[0093] 13. The vehicle according to any of the preceding clauses, wherein the systematic error is defined by the following formula: Where s is the system error, and NpError is the power turbine speed error. λ is the power turbine speed error rate, and λ is the bandwidth associated with the one or more processors executing the active control module.

[0094] 14. The vehicle according to any of the preceding clauses, wherein the active control module includes a deadband indicating a system error band, wherein the second fuel flow demand is determined to be zero when the system error is within the deadband, and wherein the second fuel flow demand is determined to be non-zero when the system error is not within the deadband.

[0095] 15. The vehicle according to any of the preceding clauses, wherein the vehicle is a helicopter and the rotor is the main rotor of the helicopter.

[0096] 16. A non-transitory computer-readable medium comprising computer-executable instructions, which, when executed by one or more processors associated with a gas turbine engine, cause the one or more processors to: determine a first fuel flow demand based at least in part on a power demand rate associated with a load mechanically coupled to the gas turbine engine by executing a feedforward module; determine a second fuel flow demand based at least in part on i) a power turbine speed error associated with a power turbine of the gas turbine engine; and ii) a power turbine speed error rate derived from the power turbine speed error by executing an aggressive control module; determine a third fuel flow demand based at least in part on the power turbine speed error by executing a power turbine regulator module; determine a synthesized fuel flow demand based at least in part on the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand; and control the fuel flow to the gas turbine engine based at least in part on the synthesized fuel flow demand.

[0097] 17. The non-transitory computer-readable medium according to any of the preceding clauses, wherein, when executing the computer-executable instructions to determine the second fuel flow demand by executing the active control module, the one or more processors: calculate a system error based at least in part on the relationship between the power turbine speed error, the power turbine speed error rate, and the bandwidth of the one or more processors executing the active control module, and wherein the second fuel flow demand is determined based at least in part on the system error.

[0098] 18. A non-transitory computer-readable medium according to any of the preceding clauses, wherein the systematic error is defined by the following formula: Where s is the system error, and NpError is the power turbine speed error. λ is the power turbine speed error rate, and λ is the bandwidth associated with the one or more processors executing the active control module.

[0099] 19. The non-transitory computer-readable medium according to any of the preceding clauses, wherein the active control module includes a dead band indicating a system error band, wherein the second fuel flow requirement is determined to be zero when the system error is within the dead band.

[0100] 20. The non-transitory computer-readable medium according to any of the preceding clauses, wherein the second fuel flow requirement is determined to be non-zero when the system error is not within the dead zone.

[0101] 21. A method comprising: determining a first fuel flow demand based at least in part on a power demand rate associated with a rotor of an aircraft, the rotor being mechanically coupled to a gas turbine engine having a power turbine, by executing one or more processors of a feedforward module; determining a second fuel flow demand based at least in part on a power turbine speed error associated with the power turbine and a power turbine speed error rate derived from the power turbine speed error, by executing one or more processors of a power turbine regulator module; determining a third fuel flow demand based at least in part on the power turbine speed error, by executing one or more processors of a power turbine regulator module; determining a composite fuel flow demand by the one or more processors based at least in part on the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand; and controlling the fuel flow to the gas turbine engine by the one or more processors based at least in part on the composite fuel flow demand.

[0102] 22. A gas turbine engine, comprising: a power turbine mechanically coupled to a rotor; and one or more processors configured to: determine a first fuel flow demand based at least in part on a power demand rate associated with the rotor by executing a feedforward module; determine a second fuel flow demand based at least in part on a power turbine speed error associated with the power turbine and a power turbine speed error rate derived from the power turbine speed error by executing an aggressive control module; determine a third fuel flow demand based at least in part on the power turbine speed error by executing a power turbine regulator module; determine a synthesized fuel flow demand based at least in part on the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand; and control the fuel flow to the gas turbine engine based at least in part on the synthesized fuel flow demand.

[0103] 23. An engine controller comprising: one or more memory devices; and one or more processors configured to: determine a first fuel flow demand based at least in part on a power demand rate associated with a load mechanically coupled to an engine, the engine being associated with the engine controller; determine a second fuel flow demand based at least in part on a power turbine speed error associated with a power turbine of the gas turbine engine and a power turbine speed error rate derived from the power turbine speed error; determine a third fuel flow demand based at least in part on the power turbine speed error; determine a composite fuel flow demand based at least in part on the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand; and control the fuel flow to the gas turbine engine based at least in part on the composite fuel flow demand.

Claims

1. A gas turbine engine, characterized in that, include: A power turbine, which is mechanically connected to a load. as well as One or more processors, said one or more processors being configured to: The first fuel flow requirement is determined at least in part based on the power demand rate associated with the load; The second fuel flow requirement is determined at least in part based on the power turbine speed error associated with the power turbine and the power turbine speed error rate derived from the power turbine speed error; The third fuel flow requirement is determined at least in part based on the power turbine speed error; The synthesized fuel flow requirement is determined at least in part based on the first fuel flow requirement, the second fuel flow requirement, and the third fuel flow requirement; and The fuel flow to the gas turbine engine is controlled at least in part based on the synthetic fuel flow requirements.

2. The gas turbine engine according to claim 1, characterized in that, in, The one or more processors execute a feedforward module to determine the first fuel flow requirement based at least in part on the power demand rate associated with the load.

3. The gas turbine engine according to claim 1, characterized in that, in, The one or more processors execute the power turbine regulator module to determine the third fuel flow requirement based at least in part on the power turbine speed error.

4. The gas turbine engine according to claim 1, characterized in that, in, The one or more processors execute an active control module to determine the second fuel flow requirement based at least in part on the power turbine speed error associated with the power turbine and the power turbine speed error rate derived from the power turbine speed error.

5. The gas turbine engine according to claim 4, characterized in that, in, When determining the second fuel flow requirement, the one or more processors are configured to: The system error associated with the load is calculated at least in part based on the relationship between the power turbine speed error, the power turbine speed error rate, and the bandwidth of the one or more processors executing the active control module. The second fuel flow requirement is determined at least in part based on the system error.

6. The gas turbine engine according to claim 5, characterized in that, in, The systematic error is defined by the following formula: in This is the system error. It is the speed error of the power turbine. It is the speed error rate of the power turbine, and It is the bandwidth associated with the one or more processors that execute the active control module.

7. The gas turbine engine according to claim 5, characterized in that, in, The active control module includes a dead band indicating the system error band, wherein the second fuel flow requirement is determined to be zero when the system error is within the dead band.

8. The gas turbine engine according to claim 7, characterized in that, in, When the system error is not within the dead zone, the second fuel flow requirement is determined to be non-zero.

9. The gas turbine engine according to claim 1, characterized in that, in, In determining the fuel flow requirements for the synthesis, the one or more processors are configured as follows: The first fuel flow demand, the second fuel flow demand, and the third fuel flow demand are summed, wherein the synthesized fuel flow demand is the sum of the first fuel flow demand, the second fuel flow demand, and the third fuel flow demand.

10. The gas turbine engine according to claim 4, characterized in that, in, The one or more processors execute the power turbine regulator module to determine the third fuel flow requirement based at least in part on the power turbine speed error, wherein the active control module and the power turbine regulator module are modules of the feedback regulation module and are arranged in parallel with respect to each other.

11. A carrier, characterized in that, include: Rotor; A gas turbine engine, mechanically connected to the rotor, the gas turbine engine including a power turbine; and One or more processors, said one or more processors being configured to: By executing the feedforward module, the first fuel flow requirement is determined at least in part based on the power demand rate associated with the rotor of the vehicle; The second fuel flow requirement is determined by executing an active control module based at least in part on the power turbine speed error associated with the power turbine, the power turbine speed error rate derived from the power turbine speed error, and the bandwidth of the one or more processors executing the active control module. The third fuel flow requirement is determined, at least in part, based on the power turbine speed error, by executing the power turbine regulator module. The synthesized fuel flow requirement is determined at least in part based on the first fuel flow requirement, the second fuel flow requirement, and the third fuel flow requirement; and The fuel flow to the gas turbine engine is controlled at least in part based on the synthetic fuel flow requirements.

12. The carrier according to claim 11, characterized in that, in, When determining the second fuel flow requirement by executing the active control module, the one or more processors are configured to: The system error associated with the rotor is calculated at least in part based on the relationship between the power turbine speed error, the power turbine speed error rate, and the bandwidth of the one or more processors executing the active control module. The second fuel flow requirement is determined at least in part based on the system error.

13. The carrier according to claim 12, characterized in that, in, The systematic error is defined by the following formula: in This is the system error. It is the speed error of the power turbine. It is the speed error rate of the power turbine, and It is the bandwidth associated with the one or more processors that execute the active control module.

14. The carrier according to claim 12, characterized in that, in, The active control module includes a dead band indicating the system error band, wherein the second fuel flow demand is determined to be zero when the system error is within the dead band, and wherein the second fuel flow demand is determined to be non-zero when the system error is not within the dead band.

15. The carrier according to claim 11, characterized in that, in, The carrier is a helicopter and the rotor is the main rotor of the helicopter.

16. A non-transitory computer-readable medium comprising computer-executable instructions, characterized in that, When the computer-executable instructions are executed by one or more processors associated with the gas turbine engine, the one or more processors cause the one or more processors to: By executing the feedforward module, the first fuel flow requirement is determined at least in part based on the power demand rate associated with the load mechanically coupled to the gas turbine engine; The second fuel flow requirement is determined by executing an active control module based at least in part on i) the power turbine speed error associated with the power turbine of the gas turbine engine; and ii) the power turbine speed error rate derived from the power turbine speed error. The third fuel flow requirement is determined, at least in part, based on the power turbine speed error, by executing the power turbine regulator module. The synthesized fuel flow requirement is determined at least in part based on the first fuel flow requirement, the second fuel flow requirement, and the third fuel flow requirement; and The fuel flow to the gas turbine engine is controlled at least in part based on the synthetic fuel flow requirements.

17. The non-transitory computer-readable medium according to claim 16, characterized in that, in, When executing the computer-executable instructions to determine the second fuel flow requirement by executing the active control module, the one or more processors: The system error is calculated at least in part based on the relationship between the power turbine speed error, the power turbine speed error rate, and the bandwidth of the one or more processors executing the active control module. The second fuel flow requirement is determined at least in part based on the system error.

18. The non-transitory computer-readable medium according to claim 17, characterized in that, in, The systematic error is defined by the following formula: in This is the system error. It is the speed error of the power turbine. It is the speed error rate of the power turbine, and It is the bandwidth associated with the one or more processors that execute the active control module.

19. The non-transitory computer-readable medium according to claim 17, characterized in that, in, The active control module includes a dead band indicating the system error band, wherein the second fuel flow requirement is determined to be zero when the system error is within the dead band.

20. The non-transitory computer-readable medium according to claim 19, characterized in that, in, When the system error is not within the dead zone, the second fuel flow requirement is determined to be non-zero.

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