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ABSOLUTE FLOW CONTROL AVTECH Sweden AB Linköpings University.

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Presentation on theme: "ABSOLUTE FLOW CONTROL AVTECH Sweden AB Linköpings University."— Presentation transcript:

1 ABSOLUTE FLOW CONTROL AVTECH Sweden AB Linköpings University

2 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 CAAChief Test Pilot Saab 340 Certif. SASLine 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

3 AIR TRAFFIC CONTROL - problem solving of a continuously selfgenerating chaotic situation – ¤DENSITY VARIATIONS ¤ ATC INTERVENTION ¤ STRATEGIC planning – TACTICAL intervention ¤ SLOT TIMES

4 SEPARATION VIOLATION CONFLICT None – Metered Flow Flow Time Min. separation WASTE

5 Metered Flow Inbound Flow Time Final approach- ATC Approach Control METERING Conflict Land None-metered Flow Maximum approach flow RWYRWY En-route Minimum landing separation OLD AOC -X

6 DISTANCE vs TIME 8 NM / minute 2,5 NM / minute NM / minute ? Distance compression

7 Metered Flow Inbound Flow Time Final approach- FineMETERINGFineMETERING Land RWYRWY En-route Minimum landing separation ATM Flow planning METERING NEW Maximum approach flow AOC

8 METERED FLOW 4-D NAV 4-D NAV Planning # 4-D NAV 4-D NAV Execution # Optimum flight (Free Flight)

9 Routes Flown for Trials 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.


11 TRAIL 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.

12 TRAIL Mixed equipage Failure cases – backup Wind information / Speed Profile Parallel runways

13 CONTROL METHODS Number of touch downs Touchdown separation (time) Sep. min Old OLD Distance control Information transfer lag Accuracy New NEW Time control Update rate Stability

14 OBJECTIVE Investigate methods to increase air traffic flow (runway throughput) up to physical or regulatory limits reduce waste of airspace increased flow (throughput)

15 OBJECTIVE Understand Air Traffic Flow and define Control Mechanisms to -STABILISE Flow -MAXIMISE Flow APPROACH & LANDING (ARRIVAL RATE / RUNWAY THROUGHPUT)

16 OBJECTIVE Improved understanding of - Flow characteristics - Flow disturbances and propagation /damping - Flow control 1 2

17 Maximum advantage with minimum changes to procedures and infrastructure

18 Traffic flow characteristics Compressibility Density – Aircraft performance – Pilot/Controller performance 3-dimensional flow

19 Flow – Density Relation to 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

20 ROAD TRAFFIC FLOW Old problem (1950) Flow models Similarities with Air traffic flow – Precision of a second – Compressible Differences – Need of speed – Leakages of flow

21 Flow - density Final approach Traffic stream K opt => q max K max = sep. min Resulting Flow, q (veh/hr) Planned Density, k (veh/mi) k opt k max Free flow Forced flow Over saturated flow V max V min q max

22 Touch down distribution Number of touch downs Touch down separation (time) Sep. min Present system Improved system Reduction of waste

23 Present ATC control loop PilotAircraft Radar Controller

24 Improved control loop PilotAircraft High accuracy A/C position ADS-B Controller F(t) F(t) = Control law

25 Automatic control loop Pilot Aircraft GNSS Controller F(t) F(t) = Control law

26 TRAIL CONTROL LAW Requires relative position and Ground Speed PDI-Controller Input = Time Error Output = Acceleration Required time Time error Air – Air Information Relative Position

27 String control Absolute reference control

28 Example Conditions – String control – Speed adjustment – PDI-Controller – 1Hz update frequency – Equal aircraft performance – Stable string – Final approach

29 Speed profile GS (m/s) 113 85 67 1 NM19 NMDistance flown from start of run

30 Speed – Distance

31 Time error – time

32 RESULTS Flow Control – Stable – High precision (milliseconds) Required developments – Phase shifted speed profile – Information transfer lag – Gross control

33 ¤TRAIL separation Control accuracy measured in meters and fractions of a second ¤TRAIL separation that approach legal and physical limits (ROT, WING VORTEX) FINDINGS

34 AIRBORNE -Systems available now (4-D Nav.) or soon (TRAIL) - Compatible procedures GROUND -Technical Systems modifications simple ! -- Procedures and responsibilities ??? FINDINGS

35 Factors That Affects Flow Controllers precision and authority Disturbancese, For example: Mix of aircraft Environmental Conditions Navigation accuracy Buffer – Time – Track

36 Planning Metered vs Unmetered Flow Negotiation/Renegotiation Sequencing Ground Air TRAIL vs 4-D Execution Old FMS, DME/DME New FMS, GNSS Mixed equipage Accuracy and stability REQUIRED STUDY

37 Track adjustment - gross control IAS Speed adjustment - fine control CONTROL POWER

38 TRAIL Speed Correction Authority Track Correction Control Law Robustness Update rate (stability) Information Transfer Lag (accuracy) Disturbance Mixed performance REQUIRED STUDY


40 STRATEGIC PLANNING based on 4-D navigation CONCEPT 4-D navigation or transition to TRAIL STATEGIC PLANNING based on 4-D navigation information OPTIMUM FLIGHT based on 4-D navigation PLANNING AND EXECUTING A METERED FLOW

41 ATC ¤ STRATEGIC planning – TACTICAL intervention ATM ¤ STRATEGIC planning – TACTICAL intervention ATS

42 4-D NAV Position determination # Silos/Railroad tracks #FMS -DME/DME -GNSS #Time

43 4-D NAV Requires common time base #Sequencing -Strategic Planning -Tactical Intervention

44 RTA Time-Control Window Control Power 3 % Gain 7 % Loss

45 Example of Modeled vs. Actual Descent Winds

46 - Present Air Traffic Management is a series of disconnected events conspiring to prevent the efficient conduct of flight -

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