BACKGROUND
The field of the invention relates generally to local loop
closure of a component for use in a gas turbine engine.
Generally, gas turbine engines have numerous variable
geometry features which are typically actuated by closed loop hydro-mechanical
control systems. These control systems are typically comprised of actuators, sensors,
and servo-valves all driven by loop closing electronics and software. The loop
closing electronics and software reside in an electronic engine control unit that is
positioned a significant distance away from the actuation hardware resulting in
substantial electrical cabling, as well as control delays due to the separation. The
amount of electrical cabling between these components is known to drive a significant
portion of the weight within an engine as well as offer additional opportunities for
failures. When system failures occur, it is often difficult to tell which part has failed
due to the separation. Often, as a result of the failures, unsuccessful maintenance is
undertaken or a "shotgun maintenance" approach is used, wherein several parts are
removed at once to insure the problem is resolved.
BRIEF DESCRIPTION
In one embodiment, a component for use in a gas turbine
engine is provided. The component includes at least one of an actuator and a servovalve,
at least one sensor, and an electronic module comprising controller electronics
and memory. The electronic module is configured to receive and process commands
for the at least one of an actuator and a servo-valve and queue received commands in
an input buffer.
In another embodiment, a method for use in operating a
component of a gas turbine engine is provided. The method includes receiving, by the
component, commands for a hardware module of the component, processing, by the
component, the received commands for the hardware module, and queuing, by the
component, the received commands in an input buffer.
In yet another embodiment, one or more non-transitory
computer-readable storage media having computer-executable instructions embodied
thereon is provided. When executed by a processor, the computer-executable
instructions cause the processor to receive, by a component of a gas turbine engine,
commands for a hardware module of the component, process, by the component, the
received commands for the hardware module, and queue, by the component, the
received commands in an input buffer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1-3 show exemplary embodiments of the method and
system described herein.
FIG. 1 is a schematic view of a component in accordance with
an exemplary embodiment of the present disclosure;
FIG. 2 is a data flow of the smart component shown in FIG.
1; and
FIG. 3 is a data flow of an integrator shown in FIG. 2.
DETAILED DESCRIPTION
The following detailed description illustrates embodiments of
the invention by way of example and not by way of limitation. It is contemplated that
the invention has general application to analytical and methodical embodiments of
sensing process parameters in industrial, commercial, and residential applications.
As used herein, an element or step recited in the singular and
proceeded with the word "a" or "an" should be understood as not excluding plural
elements or steps, unless such exclusion is explicitly recited. Furthermore, references
to "one embodiment" of the present invention are not intended to be interpreted as
excluding the existence of additional embodiments that also incorporate the recited
features.
FIG. 1 is a schematic view of a component 100 in accordance
with an exemplary embodiment of the present disclosure. In the exemplary
embodiment, component 100 is a hydro-mechanical control system that is used with a
gas turbine engine. In the exemplary embodiment component 100 is driven by signals
from upstream controller software 102 and power for component 100 is provided by
power supply 104.
Component 100 includes an electronic module 106 that is in
communication with component electrical hardware 108. In the exemplary
embodiment, electrical hardware 108 includes, but is not limited to, linear or rotary
actuators, position feedback sensors, and electro-hydraulic servo-valves. Electronic
module 106 includes data bus interface circuitry 110, power interface circuitry 112,
component specific circuitry 1 14, and a common loop closer module 11 6. Data bus
interface circuitry 1 10 transmits signals from software 102 to component 100 and
power interface circuitry 112 is in cokmunication with power supply 104 that is
configured to power component 100. Component specific circuitry 114 is in
communication with component electrical hardware 108 and is configured to translate
signals emanating from hardware 108 into module 106. In the exemplary
embodiment, component specific circuitry 114 utilizes firmware and non-volatile
media that is specific to hardware 108. In another embodiment the electronic
elements 110, 112, 114, and 116 could be implemented as a single integrated design
that provides similar hnctionality.
Common loop closer module 116 includes firmware, nonvolatile
media, and control electronics configured to process input signals and provide
output demands to control hardware. In the exemplary embodiment, common loop
closer module 116 is configured to receive communication from data bus interface
circuitry 1 10, power interface circuitry 1 12, and component specific circuitry 1 14 and
to process the communication locally within component 100.
FIG. 2 is a data flow 200 within component 100 shown in
FIG. 1. In the exemplary embodiment, data 202 is introduced into flow 200 and
received by a buffer 204. In the exemplary embodiment, data 202 are command
signals utilized for operation of hardware 108. Alternatively, data 202 can be any
signal that could be transmitted and processed by component 100 as described herein.
In one embodiment, data 202 is received by buffer 204 every 10 milliseconds.
Alternatively, data 202 can be updated to buffer at any time increment including but
not limited to asynchronously, every 1 millisecond, every 2 milliseconds, and every
20 milliseconds. Data 202 can originate from any portion of a gas turbine including
but not limited to software 102 shown in FIG. 1 or a primary processing unit such as a
Full Authority Digital Engine Control (FADEC).
Buffer 204 is configured to queue data 202 before*a mode is
selected 206. In the exemplary embodiment, when input signal 202 fails or command
data signals 202 are not updated, the local controller can continue to close the loop,
positioning hardware 108, following the trajectory prescribed in buffer 204, which
was continuously updated with the desired failure position and trajectory information.
In one embodiment, input buffer 204 includes failure instructions that command
hardware 108 to operate in a predetermined manner as a result of a loss of input signal
202.
In one embodiment, a mode is selected 206 from a mode
select signal 208 that is not part of data 202. Mode select 206 is a command relating
to the operation of hardware 108. Mode select 206 is configured to execute
commands such as, but not limited to, an auto check, an auto calibration, a health test,
and an inactivity command. After a mode is selected 206, data 202 is subject to rate
limiting and additional loop compensation 210. In one embodiment, input limits 212
are provided that correspond to the specifics of component 100. In the exemplary
embodiment, the rate of data 202 is limited by the input limits 2 12 and modified by
leaflag dynamics to determine an optimal input signal for the loop.
A proportional gain table 214 is then utilized to provide 21 5 a
shaped gain. Proportional gain table 214 supports both a simple fixed gain, or as an
input adjustment, an increasing gain with error (gain kicker) for improved response
tracking at high rates. In one embodiment, calibration data 216 is provided to
hardware gain function 217 to modify data flow from gain 215. In such an
embodiment, calibration data 216 is retrieved from local non-volatile memory.
Calibration data 21 6 includes information such as, but not limited to, trim, bias, gain,
and potential dynamic compensation values which are used locally for signal
calibrations and corrections. Calibration data 216 improves nominal feedback
accuracy and hardware 108 null shifts and gains.
In the exemplary embodiment, loop compensation variables
218 are provided to loop compensation 219 to optimize closed loop dynamic
response. In one embodiment, loop compensation variables 218 are phase leads that
are updated by adjustment over the command data bus. A gain scalar 220 is applied
to multiplier 221 to adjust for predictable gain variations. In the exemplary
embodiment, gain scalar 220 is defined by adjustment over the command data bus. In
another embodiment, gain scalar 220 is a function stored in local non-volatile
memory. In the exemplary embodiment, an integrator function 222, described in
more detail below, is used to reduce tracking errors due to unpredicted servovalve null
shifts and motion.
In the exemplary embodiment, a null bias 224 is provided to
accommodate a predictable shift that may result from load or pressure changes. In
one embodiment, null bias 224 is defined by adjustment over the command bus. In
one embodiment, null bias 224 is normalized in units of actuator rate (e.g. %/set).
Null bias 224 is set for each specific application and assists a null bias integrator, and
reduces transient impulse due to resets and channel transfers. In one embodiment,
null bias 224 is used in real time to correct tracking errors due to pressure and load
leakage.
Range limits 226 are then utilized by a torque motor driver
227 before being passed to a driver enable function 228 that is configured to allow
control of hardware 108. In the exemplary embodiment, range limits 226 support
either active-active or active-standby architecture. In one embodiment, if two
channels are being utilized for component 100, half of range limits 226 would be used
on each channel. Driver enable signal 229 is defined by adjustment over the
command bus to disable driver 228 outputs. Driver enable 230 is an independent
hard-wired input signal that provides additional failure accommodation options, not
available using only the data bus for channel selection. In one embodiment, driver
enable 230 is jumpered in the component interface connector for applications where
this function is not required.
In the exemplary embodiment, component 100 and flow 200
include sensors 232 and 234 that are configured to provide feedback to component
100. Sensors 232 and 234 monitor engine operation and input real-time actual sensor
data. Position feedback sensor 232 is used to close the position control loop, other
sensors 234, include pressures and temperatures within component 100, but also may
include other sensors across the engine, such as a fan inlet temperature sensor, a
compressor inlet total pressure sensor, a fan discharge static pressure sensor, a
compressor discharge static pressure sensor, an exhaust duct static pressure sensor, an
exhaust liner static pressure sensor, a flame detector, an exhaust gas temperature
sensor, a compressor discharge temperature sensor, a compressor inlet temperature
sensor, a fan speed sensor, and a core speed sensor. Local sensors 232 and 234
facilitate operation of component 100 as well as local compensation for typical
sources of variation such as temperature, pressure, and load.
In one embodiment, sensor 232 is a position sensor and
sensor 234 is a pressure sensor that both provide feedback to a position calibration
function 236. Position calibration 236, in addition to information received from
sensors 232 and 234, receives calibration data 238 fiom local non-volatile media. In
one embodiment, data received by position calibration function 236 is coupled with
data from torque motor driver 227 and transmitted to a health and status logic 240,
which outputs feedback, health and status data 242. Feedback, health and status data
242 can include any information about component 100 including, but not limited to,
position, voltages, currents and null bias information. In one embodiment, health and
status data is utilized by the FADEC for higher level redundancy management &
channel selection.
7
In one embodiment, data received by position calibration
function 236 is transmitted to loop compensation 244 such that leadllag dynamics can
be optimized. In the exemplary embodiment, loop compensation 244 utilizes loop
compensation variables 246 to modify feedback dynamic response characteristics
before data is coupled with data emanating from rate limiting and loop compensation
2 10. In one embodiment, loop compensations 210, 219, and 244 are operated such
that if local inner loop operates at a significantly higher update rate and bandwidth on
the command bus than biased position commands coming over the command bus
from an upstream location, loop compensations 210,219, and 244 can be utilized as a
smoothing function to reduce inner loop noise caused by command stair-steps.
FIG. 3 is a data flow of integrator function 222 shown in FIG.
2. In the exemplary embodiment, data received by position calibration function 236 is
transmitted to integrator function 222 via an integrator lock and unlock feature 250.
In one embodiment, hardware position based limits 252 are provided to feature 250
along with data received by position calibration 236 before being passed to integrator
262. Feedback based integrator lock and unlock limits 252 are defined by adjustment
over the command bus. In one embodiment, feature 250 is utilized as a separate
feature, such that integration should reset to zero during power-up or reset.
In the exemplary embodiment, an integrator function input
254 is provided to integrator function 222 and modified 257 in relation to a threshold
256 to determine if integration is necessary. In one embodiment, threshold 256 is a
discrete value, such as, but not limited to 1 milliamp. Alternatively, threshold 256 can
be any value that facilitates integration as described herein. Input 254 is then checked
259 against input limit 258 to limit the maximum integrator input before an integrator
gain 260 is applied 261. In the exemplary embodiment integrator gain is defined by
adjustment over the command bus and is a function of pressure or expected loads.
In the exemplary embodiment, an integrator 262 receives data
from integrator lock and unlock feature 250, input 254, and zerohold inputs 264.
Integrator 262 then integrates to provide an integrator output 265. Output 265 is
compared 267 with output authority limits 266 to determine if a present value of an
error is determined to exceed a predetermined threshold. If a present value of an error
is determined to exceed a predetermined threshold, an integrator function output 268
is limited to the output authority limit values 266. In the exemplary embodiment
authority limits 266 are defined by adjustment over the command bus.
In the exemplary embodiment, integrator function 222 is
shown to be placed after a gain scalar 220 is applied 221. However, integrator
function 222 can be utilized anywhere within data flow 200 that facilitates local loop
closing as described herein.
As used herein, the terms "software" and "firmware" are
interchangeable, and include any digital signal flow logic stored in memory for
execution by controller circuitry, including RAM memory, ROM memory, EPROM
memory, EEPROM memory, and non-volatile RAM (NVRAM) memory. As used
herein, the terms "controller" and/or "controller circuitry" include a processor
configured to at least execute instructions and process signals. The above memory
types are exemplary only, and are thus not limiting as to the types of memory usable
for storage of logic and controller instructions.
As will be appreciated based on the foregoing specification,
the above-described embodiments of the disclosure may be implemented using
computer programming or engineering techniques including computer software,
firmware, hardware or any combination or subset thereof. Any such resulting
program, having computer-readable code means, may be embodied or provided within
one or more computer-readable media, thereby making a computer program product,
i.e., an article of manufacture, according to the discussed embodiments of the
disclosure. The computer readable media may be, for example, but is not limited to, a
fixed (hard) drive, diskette, optical disk, magnetic tape, semiconductor memory such
as read-only memory (ROM), and/or any transmittinglreceiving medium such as the
Internet or other communication network or link. The article of manufacture
containing the computer code may be made andlor used by executing the code
directly from one medium, by copying the code from one medium to another medium,
or by transmitting the code over a network. In the exemplary embodiment, all
software logic located locally is fmware and does not change for most applications.
The tuninglconfiguring of this firmware is provided by inputs from the upstream
processors.
The above-described embodiments of a method and system
for local loop closer provides a reliable means for closing electronics into a single
unit. As such, processing demands on high demand processing systems is reduced.
The elimination of cabling also provides a weight reduction to engines utilizing the
methods and system described herein. Additionally, processing bandwidth can be
increased significantly resulting in significant performance improvements. Also,
improved reversionary modes and fault accommodation are provided with less
hardware redundancy. Failure accommodation and reversionary modes are
significantly improved over legacy, using the input buffer feature.
The embodiments described above also provide smoothing &
asynchronous operation features to support significantly higher loop closure update
rates (< 2 ms), enabling enhanced tracking performance and disturbance rejection,
trajectory based input signal buffering for improved failure accommodation, and
selectable maintenance modes and NVM storage of data to support automatic rigging
and calibration. Additionally, fewer connections provide improved reliability, and
improved supportability is provided due to better faultlfailure isolation. Also because
of the localization of processing, the embodiments above provide for improved
reversionary modes and accommodation of failures. In the exemplary embodiment
several input parameters are provided over the command data bus. These inputs are
provided at various update rates, with the most time-critical command signals
provided at the highest rate. Other less time-critical inputs, such as, but not limited to,
compensation and limits can be provided at much lower rates to reduce data bus
traffic without limiting loop closer performance. In another embodiment, many of
these inputs do not require regular adjustment, and utilize data values stored as nonvolatile
memory within component 100. If adjustment is desired, these data values
are replaced by data provided over the command data bus.
This written description uses examples to disclose the
invention, including the best mode, and also to enable any person skilled in the art to
practice the invention, including making and using any devices or systems and
performing any incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to those skilled in
the art. Such other examples are intended to be within the scope of the claims if they
have structural elements that do not differ from the literal language of the claims, or if
they include equivalent structural elements with insubstantial differences from the
literal languages of the claims.

WE CLAIM :
1. A component (100) for use in a gas turbine engine, said
component comprising:
at least one of an actuator and a servo-valve;
at least one sensor (232 and 234); and
an electronic module (106) comprising a controller and memory, said
electronic module configured to:
receive and process commands for the at least one of an
actuator and a servo-valve; and
queue received commands (202) in an input buffer (204).
2. A component in accordance with Claim 1, wherein said
electronic module configured to queue received commands in an input buffer is
further configured to queue received commands in an input buffer having failure
commands stored within the input buffer.
3. A component in accordance with Claim 2, wherein said
electronic module is configured to execute failure commands upon the loss of
received commands in the input buffer.
4. A component in accordance with Claim 1, wherein said
electronic module is further configured to provide leadlag compensation to the
received commands.
5. A component in accordance with Claim 1, wherein said
electronic module is further configured to receive and process a first input at a first
data rate and a second input at a second data rate.
6. A component in accordance with Claim 1, wherein said
electronic module is further configured to provide at least one of a null bias
integration and adjustable gains to the control loop.
7. A component in accordance with Claim 1, wherein the at least
one sensor is at least one of a pressure, temperature, and load sensor.
8. One or more non-transitory computer-readable storage media
(102) having computer-executable instructions embodied thereon, wherein. when
executed by a controller, the computer-executable instructions cause the controller to:
receive, by a component (100) of a gas turbine engine, commands
(202) for a hardware module (108) of the component;
process, by the component, the received commands for the hardware
module; and
queue, by the component, the received commands in an input buffer
(204).
9. One or more non-transitory computer-readable storage media
according to Claim 8, wherein the computer-executable instructions cause the
controller to store failure commands within the input buffer.
10. One or more non-transitory computer-readable storage media
according to Claim 9, wherein the computer-executable instructions cause the
controller to execute failure commands upon the loss of received commands in the
input buffer.