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Software Enabled Control Principle Investigators MeetingSoftware Enabled Control Principle Investigators MeetingNovember 13November 13--15, 200115, 2001

Major Andrew “Rocket” ThurlingMajor Andrew “Rocket” Thurling Mr. Thomas LandersMr. Thomas LandersUSAF Test Pilot SchoolUSAF Test Pilot School Veridian EngineeringVeridian Engineering

VISTA VISTA –– a 21a 21stst Century Century TestbedTestbed

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L Outline• Outline• VISTA………….• What is it?• What has it done?• How would I use it?• What can it do for me?

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• Variable-stability Inflight Simulator Test Aircraft• Very Highly Modified NF-16D Aircraft

–S/N 86-048–Block 30 Airframe, Peace Marble II Configuration–Block 40 DFLCC (Digital Flight Control Computer)–Block 40 (FMS) Avionics System–Heavy Weight Landing Gear–Variable Stability System (5-DOF Simulator)

VISTA

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– Removed from F-16 production line late in production for modification– First flight April 9, 1992– Four more initial checkout flights in April, 1992– MATV (Multi-Axis Thrust Vectoring) test bed 1993-1994 (95 flights)– VSS Test Flights, July 1994 – Jan. 1995 (63 flights)– Delivered to USAF (Wright-Patterson AFB) in Jan. 1995

VISTA in the MATV Configuration

VISTA History

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L VISTA History (con’t)

� Operated by Veridian Engineering (Calspan) since January, 1995 under USAF contract

� July ‘96 – June ‘97: P/W-229 engine conversion, along with wiring modification for P/W Thrust Vectoring, HMD system

� October 2000: relocated to USAF TPS (Edwards AFB)

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L VISTA Equipment Layout� “Customer” sits in the front cockpit

–Minimal F-16 responsibility�Pilot-in-command sits in the rear cockpit

–Has all primary aircraft controls

VARIABLE FEELCENTER STICK

FEEL SYSTEMCOMPUTER

F-16 SIDE STICK

DUAL VSSACCELEROMETERS

IFR RECEPTACLE

CUSTOMERSPACEVARIABLE FEEL

SIDE STICK

AOS CONESAOA CONE

ENGAGE LOGICINTERFACE CHASSIS (ELIC)

QUAD F-16 RATE GYROS

DUAL VSS COCKPIT ACCEL

DATA ACQ SYSTEM (AR700)

DUAL VSS RATE GYROS

DUAL VSS ACCELSIGNAL CONDITIONING CHASSIS (SCC)

VSS 1&2

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L VISTA VSS Computers� Full ATR Size 15 Slot Chassis� VME Open Architecture� Each Chassis:

� 233 Mhz Pentium w/512KB Cache � 128 MB ECC RAM�Analog and discrete I/O� 6 Dual Redundant 1553 Bus Interfaces� Flash Card Memory (85-330 MB)�RS-232, RS-422, SVGA, SCSI-2, Ethernet

� Interfaced to F-16 Core avionics, flight controls, “experimental systems”

� Programmed by Veridian�NOT safety of flight critical�Reprogramming can be done with a minimal amount

of “administrative overhead”�Changes can be made in less than one hour (ready to fly!)

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L VISTA: Variable Flight Controls

VariableStabilitySystem

DFLCC

Pilot disengage,Automatic monitors

F-16 CLAW

actuators

Actuator commands (5)

engine

Rear throttleThrottle

command

Sensors

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L VISTA: Simulation Architecture

Centerstick/Sidestick

Feel Sys Computer

VSS Computers

SimulationThrottle

RudderPedals

VSS andF-16

Sensors

CommandFeedforward

Gains

Actuatorand

AirframeDynamics

ResponseFeedback

Gains

FeelSystem Model

FCS

DFLCC

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L VISTA Flight Envelope

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30

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0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2Mach

Altit

ude

(x 1

000

ft) VISTA / NF-16D F-16C/D

440 KCAS

550 KCAS

800 KCAS

16 degAngle-of-Attack

VSSEngaged

VSSDis-

engaged

• VSS operational envelope slightly reduced from basic F-16 (Nz limits are +6.8/-2.44 G’s)

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LVSS Computer Operation and Control

� VSS computers are interfaced with the Multi-Function Display System (MFDS) and Up-Front Controller (UFC) to allow the VSS computers to display information and receive keystrokes

� This allows test parameters to be varied in-flight at the touch of a button

GAIN

BRT

SYM

CON

VSS MAIN MENU

BUILT IN TEST

GND SIM CONFIG

CCS

ATTITUDE DISPLAY

SAFETY TRIPS

SWAP FCRVSS1

UTILITIES

SENSOR CUEING

PROG DISPLAYSYSTEM

GAIN

BRT

SYM

CONMAINFCRSWAP VSS1

CONF+107

STBY+001

PAGE1/4

LISTPAGE

XTRACMDS

+001+000

+300+300

+100+100

+050+150

+000+006

STICK CNTR *AB ALLOWED *

E KDES CSE KFES CS

A KDAS CSA KFAS CS

E KQ1E ALP LIM

HUD CTRL 5TT S0S D1S

DECCUSTOMGAINS STOP

COPY

PRE IC

PASTESYM FLAPPITCH TRIMTEST INPUTOFF

UA CONFG CMD UNCOMP+6/-2 NZ LIM

+01.5+0.07

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• In-flight simulation of flight control system & aircraft combinations

• Basic research in the development of FCS requirements• F-22, Indian light combat aircraft, AFRL fighter handling qualities

projects, self designing controller, LM JSF, X-38

F-22

X-38

LM JSF

VISTA - Research Role

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L VISTA PROGRAMS

• F-22 In-Flight Simulation (Jan-May ’96)–Powered approach evaluations

(offset approaches to touchdown)• Mid weight/Mid CG• Light weight/Aft CG• Aero uncertainty• Single Engine failure• Single and Dual Hydraulic failure

–Aerial Refueling• Simulated in-flight refueling with KC-135 tanker• Air to Air tracking with Learjet• Formation with Learjet and KC-135

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• LCA Simulation (May-July ’96)– Powered Approach evaluations

• Heavy weight/Nominal CG• Mode transitions• Failure modes

–Formation & Air to Air Tracking• Air to Air tracking with Learjet• Formation with Learjet and NT-33• Mode transitions• Air data failure• Aero uncertainty

VISTA PROGRAMS

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• Self Designing Controller (SDC) (May-July ’96)–Demonstrated Real-time Parameter ID with simulated failure

• Missing one horizontal tail• Modified Sequential Least Squares Parameter Estimation

– Receding Horizon Optimal Control Law–Handling Qualities adequate for landing with failure

VISTA PROGRAMS

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• LM JSF CDA (Mar-Jun ’98)– Evaluated flying Qualities in PA, AR and

UA flight conditions– Various flight control options evaluated– Clearance of 370 gal ARTS with VISTA

• Evaluation of Landing, AR, UA (formation and A-A)

– Contractor and Government pilots – Conventional and Carrier type with

FLOLS approaches (98)– Air-to-air tracking & formation with F-18– Probe and drogue refueling (no fuel

transfer) w/ KC-130

VISTA PROGRAMS

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• X-38 CRV IFS (Oct ’98)– First IFS of UAV by VISTA– IFS performed on V132 Configuration– Equipped with GN&C– GN&C -- C Autocode from MatrixX

integrated easily with VSS – Validate performance of aerodynamics

and control law prior to V132 flight– Generate data for comparison with

flight tests– FADS fail performance– Exercise the VISTA model development

path in preparation for V201 (Re-entry vehicle) testing

FIRST UAV-CLASS VISTA PROGRAM

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WHY VISTA?

• Use VISTA as closed-loop test bed to minimize risks associated with unknown/unproven control laws– VISTA provides fewest compromises in conduct of tests– Minimal modification of aircraft required– VSS concept allows for rapid prototyping, easy design “tweaks”– Evaluates complete system

• Dynamics• GN&C• Weapons system surrogates• Up/Down links, if necessary

– Saves $$$

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UAV TESTING

• VISTA is an ideal test bed for UAVs

– VISTA can represent the L/D and responses typical of UAVs

– Simulates UAV flight profiles (up to and including landing)

– On board safety pilot provides for safe testing • Failures• Aero-uncertainty• Unproven control law strategies/methodologies

– Rapid prototyping allows for proof of concept testing• Reduced Verification and Validation• Rapid turn around between software changes• Customer software development cycle limiting factor

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• Pilot backup allows increased productivity–Mission planning errors not program stoppers– Increased aggressiveness in envelope expansion– Increased aggressiveness in failure mode investigation–Mission may be broken into logical segments

• Range safety considerations reduced with pilot onboard–Flight Termination Systems not required–Footprint analysis simplified

• Easily integrated with manned aircraft–Reduced risk–Less interference with manned operations–Leads to less resistance to UAV testing

UAV TESTING

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UAV TESTING

• Additional equipment space in Dorsal Equipment Bay–Closed-loop test with hardware-in-the-loop–Cooling & power available–VME slots available–Mounting locations for additional equipment

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UAV SIMULATION• VISTA Capable Of Simulating UCAV class Dynamic Responses

– VSS uses VISTA control surfaces to simulate open-loop vehicle dynamics

• HIMAT RPV Simulation Example– NASA RPV, flight tested circa ‘79-’81– Geometric Data

• Wing area 58.0 ft2

• Span 14.93 ft• MAC 4.35 ft• Weight 3163 lbs• Ixx= 436 slugs-ft2

• Iyy= 1593 slugs-ft2

• Izz= 2013 slugs-ft2

• Ixz= -81.26 slugs-ft2

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• Response Feedback Utilized– Longitudinal Response Evaluated– Elevator, Elevon & Canard inputs– M.6/10Kft– Open Loop response due to surface inputs examined– Model Following allows full envelope simulation, with non-

linearities• Response Feedback Gains

– Eigenstructure Assignment, Output feedback– Pseudo-inverse of VISTA surface effectiveness– HIMAT actuator models not used – VISTA actuators impact time delay associated with simulating

dynamics

UAV SIMULATION

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0 5 10-1

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cana

rd c

md

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0 5 10-5

0

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pitc

h ra

te (d

/s)

0 5 10-5

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0 5 10-2

-1

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alph

a (d

eg)

time0 5 10

-2

-1

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time

HIMAT CANARD COMMAND

HIMAT VISTA

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0 5 10-1

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1el

evon

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d

0 5 10-10

0

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0 5 10-5

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pitc

h ra

te (d

/s)

0 5 10-5

0

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0 5 10-2

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alph

a (d

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time0 5 10

-2

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time

HIMAT ELEVON COMMAND

HIMAT VISTA

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0 5 10-1

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evat

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md

0 5 10-10

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0 5 10-10

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pitc

h ra

te (d

/s)

0 5 10-10

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alph

a (d

eg)

time0 5 10

-5

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time

HIMAT ELEVATOR COMMAND

HIMAT VISTA

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• HIMAT Representative Of Small To Mid-sized UAV– Larger vehicles possible– Flight Control & Guidance System would be implemented

identically to vehicle in question• Possible Objectives

–Control Law Development/Refinement/Validation–Failure modes and reconfiguration strategy testing/validation–Data Link Evaluation and Development–Weapons System Development–Concept of Operations development

UAV SIMULATION

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L UAV TESTING

• Potential Evaluations–Nominal and Failure states–Possible UAV or RLV testing:

– Approach and Landings– Wave-off/go-around – Probe and Drogue refueling – Boom refueling (pre-contact position only)– Formation– Air-to-Air engagements– Air-to-Ground engagements– Failure modes– Reconfiguration/Safe modes

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L UAV TESTING

• Model/Data Requirements–Model and FCS Software

• VISTA has successfully hosted the following software:–Ada 83 & 95 (primary software of VSS)–FORTRAN 77, 90–C, C++

• VISTA has successfully hosted the following Autocode:–MatrixX C & Ada Autocode–Simulink/Matlab C Autocode

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L CONCLUSIONS

• VISTA is a proven risk reduction tool• VISTA provides simulated vehicle dynamics• Minimal modifications to VISTA needed for your

project (saves time and money in test prep.)• Requires few compromises in test conduct• Manned backup provides safety/risk mitigation• Weapon systems surrogate for combat UAV test

• Low-cost insurance policy

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L VISTA ORGANIZATION

USAFTPS/CCCol George Ka’iliwai

VISTAProgram ManagerMajor Andy Thurling

Deputy Program ManagerSharlene Lim

VISTA Maintenance TeamVeridian/USAF

Veridian Program MgrTom Landers

Contract ManagerJeanne Gare

Plans/ProgramsMajor Thurling

VISTA Test Pilots• Major Andy Thurling - Chief Research & Development Pilot• Major Rick Palo - Chief Systems Instructor Pilot• Mark Dickerson - Veridian/Edwards Instructor Pilot• Jeff Peer - Veridian/Buffalo Chief Instructor Pilot• Major Om Prakash - Instructor Pilot

Production & Mx SuperMSgt Charles Olden

Veridian Flight ResearchBuffalo, NY

VISTA Continuing DevelopmentTest Pilot Training

Engineering SupportMaintenance Support

Technical Advisor, Systems ResearchJohn Minor

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• USAF TEST PILOT SCHOOL Points of Contact– Maj. Andy Thurling, VISTA Program Manager & Chief R&D Pilot

• Comm. (661) 277-6554, DSN 527-6554• email: andrew.thurling@edwards.af.mil

– Ms. Sharlene Lim, Deputy PM, Chief of Maintenance and Logistics

• Comm. (661) 277-3046, DSN 527-3046• email: sharlene.lim@edwards.af.mil

• http://www.edwards.af.mil/tps/vista/vista.htm

• Veridian Flight Research POC– Mr. Thomas Landers, VISTA Program Manager

• Comm. (716) 631-6943• email: tom.landers@veridian.com

Who To Contact

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X-38 VISTA SUPPORT

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L UAV TESTING

• Validation Process–Reference Time histories provided by Contractor

• P, R, Y, Throttle steps, doublets • Small, moderate and large

–Predict characteristics of VISTA simulating model checked with off-line simulation

• Verified on aircraft with ground simulation–Flight Time Histories obtained during Calibration flights

• Identical test inputs injected into system–Overlaid with Reference Time histories–Contractor/Veridian agree VISTA simulating model

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L UAV TESTING

• Testing Procedures– Test Plan written by Contractor, TPS, or Veridian

• Contractor review during generation (if needed)• Submitted to TPS and Veridian for review and approval

– AFFTC Process• Technical Review Board (TRB)• Safety Review Board (SRB)

– Evaluation Flights• Contractor Test Engineer(s) and Pilots on-site• Responsible for test points and objectives of evaluation flights• Access to data within 1-2 hours of landing• 1 to 2 flights per day typical (surge to 4 possible based upon

project needs/schedules)

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L UAV TESTING

• Data–Post Flight data

• Available 1 - 2 hours from landing• Hi-8 Video for Event log, pilot comments

–Telemetry• Real time monitoring of flight data• Backup of flight data if necessary (loss of tape data)

• Test Report –Written by Veridian or TPS–Contractor review prior to distribution–Submitted to AFTPS, AFFTC, Contractor and Project Office–VISTA Contractual Requirement

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L UAV TESTING

• Model/Data Requirements–Flight Control System Block Diagrams/Code–Known FCS variations to be tested–FCS Gains & variations to be tested–Update rates–Un-augmented non-linear aero model

• For specific flight conditions (if necessary)• Simulation model preferred

–Bare airframe modal characteristics• Open & closed loop time histories

–Datalink Characteristics• Update rates and Format• Frequency• Special Antennas

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L UAV TESTING

• Model/Data Requirements (cont’d)–Actuator models

• Frequency response, rate & position limits–Sensor and signal conditioning

• Sensor dynamics• Special compensation (e.g., complementary filters)

–Definition of Axis Systems & Sign conventions–CG and Sensor Locations