ABSOLUTE FLOW CONTROL AVTECH Sweden AB Linköpings University.
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Transcript of ABSOLUTE FLOW CONTROL AVTECH Sweden AB Linköpings University.
ABSOLUTE FLOW CONTROLABSOLUTE FLOW CONTROL
AVTECH Sweden AB
Linköpings University
Jon H. Ertzgaard, AVTECH Sweden AB
RNoAF, USAF ETPS
Saab Chief Test Pilot and Project Test Manager -J35F Draken-AJ37 Viggen,
Saab 340, Saab 2000, man. guided missiles.
J39 Gripen Flight Control System
CAA Chief Test Pilot Saab 340 Certif.
SAS Line Capt., Instructor, Project Pilot,
Headed the AI/Airline A340/A320 Cockpit-Systems Integration Group
Cosultant to NASA (Ames), Fokker etc. Saab Friction Tester
Håkan Andersson, University of Linköping Master of Science, Comunication and transportation systems
AIR TRAFFIC CONTROL
”- problem solving of a continuously selfgenerating chaotic situation – ”
¤ DENSITY VARIATIONS
¤ ATC INTERVENTION
¤ STRATEGIC planning – TACTICAL intervention
¤ SLOT TIMES
SEPARATION
VIOLATION
CONFLICT
None – Metered Flow
Flow
Time
Min. separation
WASTE
Metered Flow
Inbound Flow
Time
Final approach-
ATC
Approach Control
METERING
Conflict
Land
None-metered Flow
Maximum approach flow
RWY
En-route
Minimum landing separation
OLDAOC -X
DISTANCE vs TIME
8 NM / minute
2,5 NM / minute
NM / minute?
Distance compression
Metered FlowInbound Flow
Time
Final approach-
Fine
METERING
Land
RWY
En-route
Minimum landing separation
ATM
Flow planning
METERING
NEW
Maximum approach flow
AOC
METERED FLOW
4-D NAV4-D NAV Planning
#
4-D NAV4-D NAV Execution
#
Optimum flight
(Free Flight)
Routes Flown for TrialsRoutes Flown for Trials
Malmö
Ängelholm
Luleå
Stockholm
33 RTA trial flights conducted by Smiths Aerospace with SAS.
Swedish CAA provided “undisturbed” priority servicing.
17 different flight crews.Smiths Aerospace test conductor in
jumpseat with SONY Digital-8 camcorder.
Malmö Ängelholm Luleå23 flights 8 flights 2 flights
TRAILTRAIL
Accurate Time Separation based on Distance and Ground Speed only
Tactical Sequencing and Separation tool
ATC defined – Flight Crew executed
Requires accurate positioning
Accuracy equal to or better than 4-D Nav.
TRAIL
Mixed equipage
Failure cases – backup
Wind information / Speed Profile
Parallel runways
CONTROL METHODSCONTROL METHODS
Num
ber
of to
uch
dow
ns
Touchdown separation (time)
Sep. min
Old
OLD
• Distance control•Information transfer lag
• Accuracy New
NEW
• Time control•Update rate
• Stability
OBJECTIVE
Investigate methods to increase air traffic flow (runway throughput) up to physical or regulatory limits
reduce waste of airspace
increased flow (throughput)
OBJECTIVE
Understand Air Traffic Flow and define Control Mechanisms to
- STABILISE Flow
- MAXIMISE Flow
APPROACH & LANDING (ARRIVAL RATE / RUNWAY
THROUGHPUT)
OBJECTIVE
Improved understanding of
- Flow characteristics
- Flow disturbances and propagation /damping
- Flow control
1
2
Maximum advantage
with
minimum changes to
procedures and infrastructure
Traffic flow characteristicsTraffic flow characteristics
CompressibilityDensity
– Aircraft performance– Pilot/Controller performance
3-dimensional flow
Flow – DensityFlow – Density Relation Relation toto Air-traffic Air-traffic
Method– Analogy from Road-traffic R/D– Assumed as 1-dimensional flow– Focus on final approach (traffic stream)
Definition of– Critical factors– Max and optimal density
ROAD TRAFFIC FLOWROAD TRAFFIC FLOWOld problem (1950)Flow modelsSimilarities with Air traffic flow
– Precision of a second– Compressible
Differences– Need of speed– Leakages of flow
Flow - densityFlow - density Final approach Traffic streamFinal approach Traffic stream
Kopt => qmax
Kmax = sep. min
Res
ulti
ng F
low
, q
(veh
/hr)
Planned Density, k (veh/mi)
kopt kmax
Free flow
Forced flow
Over saturated flow
Vmax
Vmin
qmax
TouchTouch dowdownn distribution distributionN
umbe
r of
touc
h do
wns
Touch down separation (time)
Sep. min
Present system
Improved system
Reduction of waste
PresentPresent ATC ATC control loop control loop
Pilot Aircraft
RadarController
Improved control loopImproved control loop
Pilot Aircraft
High accuracy A/C
positionADS-B
Controller
F(t)
F(t) = Control law
Automatic control loopAutomatic control loop
Pilot Aircraft
GNSSController
F(t)
F(t) = Control law
TRAIL CONTROL LAWTRAIL CONTROL LAW
Requires relative position and Ground Speed PDI-Controller Input = Time Error Output = Acceleration
Required time
Time error
Air – Air Information
Relative Position
String control
Absolute reference control
ExampleExample
Conditions– String control– Speed adjustment– PDI-Controller– 1Hz update frequency– Equal aircraft performance– Stable string– Final approach
Speed profileSpeed profileGS (m/s)
113
85
67
1 NM 19 NM Distance flown from start of run
Speed – Distance Speed – Distance
Time error – time Time error – time
RESULTSRESULTS
Flow Control– Stable– High precision (milliseconds)
Required developments– Phase shifted speed profile– Information transfer lag– Gross control
¤ TRAIL separation Control accuracy measured in meters and fractions of a second
¤ TRAIL separation that approach legal and physical limits (ROT, WING VORTEX)
FINDINGS
AIRBORNE-Systems available now (4-D Nav.) or soon (TRAIL) - Compatible procedures
GROUND-Technical Systems modifications ”simple” !-- Procedures and responsibilities ???
FINDINGS
Factors That Affects FlowFactors That Affects Flow
Controllers precision and authority
Disturbancese, For example: Mix of aircraft
Environmental Conditions
Navigation accuracy
Buffer – Time – Track
Planning
Metered vs Unmetered Flow
Negotiation/Renegotiation
Sequencing
Ground
AirTRAIL vs 4-D
Execution
Old FMS, DME/DME
New FMS, GNSS
Mixed equipage
Accuracy and stability
REQUIRED STUDY
Track adjustment - gross control
IAS
Speed adjustment - fine control
CONTROL POWER
TRAIL
Speed Correction Authority
Track Correction Control Law
Robustness
Update rate (stability)
Information Transfer Lag (accuracy)
Disturbance
Mixed performance
REQUIRED STUDY
AVTECH - LIU
CONSORTIUM
STRATEGIC PLANNING based on 4-D navigation
CONCEPT
4-D navigation or transition to
TRAIL
STATEGIC PLANNING based on
4-D navigation information
OPTIMUM FLIGHTbased on
4-D navigation
PLANNING AND EXECUTING A METERED FLOW
ATC ¤ STRATEGIC planning –
TACTICAL intervention
ATM
¤ STRATEGIC planning – TACTICAL intervention
ATS
4-D NAV4-D NAV
Position determinationPosition determination##
Silos/Railroad tracksSilos/Railroad tracks##
FMSFMS-DME/DMEDME/DME
-GNSSGNSS
##
TimeTime
4-D NAV4-D NAV
Requires common time baseRequires common time base##
SequencingSequencing-Strategic Planning-Strategic Planning
-Tactical Intervention-Tactical Intervention
RTA Time-Control WindowRTA Time-Control WindowControl PowerControl Power
17:24:00
17:25:26
17:26:53
17:28:19
17:29:46
17:31:12
17:32:38
17:34:05
17:35:31
276
254
225
198
167 9
5
78
63
48
32
23
13 7
2.1
Distance to RTA Waypoint (nm)
Tim
e (G
MT
)
Latest A rriva lT im e
E arliest A rriva lT im e
Descent PhaseCruiseFL350
Climb
R equired T im eof A rriva l
F light #23 D ata
h=10,000 ft
3 %Gain
7 %Loss
Example of Modeled vs. Example of Modeled vs. Actual Descent WindsActual Descent Winds
-15 -10 -5 0 5 10 150
50
100
150
200
250
300
350
400
Flig
ht
Lev
el
Headwind (knots)
Forecast Winds (entered in FMS)Actual Descent Winds
- ” Present Air Traffic Management is a series of disconnected events conspiring to prevent the efficient conduct of flight ”-