Software Enabled Control for Intelligent Uninhabited Air Vehicles UAVs Simulation and Flight Test Pr

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Software Enabled Controlfor Intelligent
Uninhabited Air Vehicles (UAVs)Simulation and
Flight Test Process

• Principal Investigators
• Daniel Schrage (AE) George Vachtsevanos (ECE)
• School of Aerospace Engineering School of
  Electrical and Computer Engineering
• Georgia Tech Georgia Tech
• Atlanta, GA 30332 Atlanta, GA 30332
• daniel.schrage_at_ae.gatech.edu george.vachtsevanos_at_e
  ce.gatech.edu
• [phone] [phone]
• Co-PIs and Key Personnel
• Bonnie Heck (ECE), Eric Johnson (AE), J.V.R.
  Prasad (AE), Linda Wills (ECE)

Contract Number F33615-98-C-1341 Award End
Date 3Q-FY04
controls.ae.gatech.edu/projects/sec
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Outline

• Walk-though of GTMax
• Hardware
• Software
• Simulation and Flight Testing Procedure
• Stand-alone Simulations
• OCP Integration
• Transition to Hardware, with Demonstration
• Flight Testing
• Take time for Discussion

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GTMax Walk-Through
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Georgia Tech R-Max GTMax

• Yamaha R-Max,
• 66kg
• 3m Rotor
• Flights Began March 2002
• Instrumented as a Research VTOL UAV
• Became Platform for DARPA Software Enabled
  Control Program University-Led Experiments in
  July 2002

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GTMax Test Event Highlights

• Low-level control reconfiguration using OCP
• First Place 2002 Aerial Robotics Competition
• Limit detection and avoidance OCP component
• Trajectory generation OCP component
• Adaptive trajectory-following flight control
• Envelope expanded 50 to 85 ft/sec speed
• Have experienced up to 40 knot gusts (estimated)
• Takeoff and landing
• Aggressive maneuvers
• Glider launch

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Since Last Time

• Since the last PI meeting (Nov 2002 - Present)
  the GTMax has had
• 4 Flight test days
• Approximately 19 flights, 5 hours in the air
• Approximately 15 flights where the autopilot was
  utilized
• 42 Segments of recorded data archived

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GTMax Hardware Components

• Flight Computers
• 266MHz 800 MHz Embedded PCs, Ethernet, Flash
  Drives
• Sensors
• Inertial Measurement Unit (x2)
• Differential GPS
• Magnetometer
• Sonar and Radar Altimeters
• Vehicle Telemetry (RPM, Voltage, Pilot Inputs)
• Data Links
• 11 Mbps Ethernet Data Link
• RS-232 Serial Data Link

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GTMax Architecture
GPS Reference
GPS
Georgia Tech Onboard Avionics
Data Link I
Data Link I
Ground Computer(s) And Network
GEORGIA TECH
Ethernet
Data Link II
Data Link II
Ground Control Station
3x RS-232 Serial
RC Receiver
Yamaha Attitude Control System (YACS)
YAMAHA
On-board Avionics
Safety Pilot
Actuators
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Basic GTMax Avionics
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GTMax Hardware Integration

• Exchangeable modules
• Flight Computer Module
• GPS Module
• Data Link Module
• IMU/Radar Module
• Unused Module (Growth)
• Sonar/Magnetometer Assemblies
• Power Distribution System
• Each module has self-contained power regulation
  and EMI shielding
• Vibration isolated main module rack

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GTMax Hardware Integration

• Power System
• On-board generator outputs 12V DC, 10 A
• Hot-swap between on-board and external power
• Each component has individual circuit breakers
• Interfacing and Wiring
• Wiring RS-232 Serial, Ethernet, 12V DC
• Easy access to modules from one side, see LEDs
• Aviation-quality wiring on the other

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Sensors IMU

• ISIS Inertial Measurement Unit (ISIS-IMU)
• Acceleration and angular velocity triads
• Analog or 100Hz digital output
• 160 deg/sec max angular rate 11G max acceleration
  (as configured for the digital interface)
• 1.1 deg/sec and 0.003G standard deviations
  measured with rotor spinning at flight RPM
• Ours is a special order that takes a 12VDC input
• www.inertialscience.com

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Sensors Differential GPS

• NovAtel RT-2 Differential GPS (MiLLenium Card)
• Carrier phase tracking
• Output of position and velocity used, WGS-84
• 5Hz update rate
• Differential correction from ground station
  communicated over both datalinks (every 2
  seconds)
• 2 cm CEP specification
• www.novatel.com
• Recently upgraded to theOEM4 version

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Sensors Magnetometer

• Honeywell 3-axis magnetometer HMR-2300
• Measures strength of magnetic field in 3
  directions
• 20 Hz digital output

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Sensors Sonar Altimeter

• Custom built sonar ranging system
• Polaroid range sensor
• Distance from terrain
• 0.5 ft to 10 ft
• 10 Hz

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Sensors Optical RPM

• (New) Custom built RPM sensing
• Optical sensor
• 1 rpm resolution
• 100 Hz

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Actuators Helicopter Interface

• Yamaha R-Max modified with the same digital
  interface used in their Autonomous R-Max
• Has four RS-232 interfaces
• Send actuator commands, turn on/off stability
  augmentation (50 Hz)
• Get commands as received from safety pilot radio
• Get Yamaha IMU data (for its SAS)
• Get other telemetry
• RPM, Voltage
• Actuator command source

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Dalalinks FreeWave

• FreeWave wireless modem
• 9600 baud (other settings possible)
• Tested up to about 2 miles with helicopter on the
  ground (worst case)

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Dalalinks AeroNet

• AeroNet wireless ethernet
• Have seen as high as 11 Mb per sec in flight
• Untested max range with directional antenna
  (should be at least a mile)

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Processors

• Primary flight computer
• 266 MHz Pentium
• 500 Mb flash drive
• QNX
• Second computer
• 800 MHz Pentium
• 500 Mb flash drive
• QNX or Linux
• Ethernet hub onboard

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Baseline Software

• Operating Systems
• Onboard (Flight) Software Linux or QNX
• Simulation Windows or Linux
• Languages and Libraries
• C/C, Utilizes OpenGL API
• No Special Compilers Needed (We Use Visual
  Studio on Windows or gcc on Linux)

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Baseline Software Overview

• Onboard software
• Primary flight computer
• GCS software
• Runs on ground control station
• Simulation software
• Not used in flight
• All of the above included in GCS/Simulation build
• Only onboard software include in onboard or OCP
  build

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Baseline Onboard Software

• Navigation
• 17 State Extended Kalman Filter Navigation System
• Vehicle Position
• Vehicle Velocity
• Vehicle Attitude
• Accelerometer Biases
• Gyro Biases
• Terrain Height
• All Attitude Capable
• 100 Hz Updates
• Flight Operational

• Control
• Adaptive Neural Network Trajectory Following
  Controller
• Neural Network
• 18 Inputs
• 5 Hidden Layer Neurons
• 7 Outputs for 7 Degrees of Freedom
• Can Also Be Configured as a Conventional
  Inverting Controller
• Flight Operational

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Baseline Navigation Filter

• Extended Kalman Filtering Approach Used to
  Integrate Sensor Data in Real Time
• IMU Data is Propagated at 100 Hz and Discretely
  Updated by All Other Sensor Measurements

Acc. / Rate
IMU
Position/ velocity
Vehicle
DGPS
Extended Kalman Filter
F M
X
azimuth
Magnetometer
h
Sonar/Radar
More Sensors
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Baseline Navigation Updates

• Differential GPS
• Mounting position and latency compensation
• Updates position and velocity state (5 Hz)
• Magnetometer
• Measures magnetic field line vector
• Corrects heading drift of the filter (20 Hz)
• Sonar/Radar
• Updates the vertical position and terrain height
  state (10 Hz/variable)
• Filter Initialization
• Based on averaged sensor data while helicopter is
  on the ground
• Initial position GPS
• Initial roll and pitch attitude, gyro biases IMU
• Initial heading magnetometer
• All other states set to zero

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Inner-Outerloop Architecture
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Neural-Network Adaptive Control
Representative of both innerloop and outerloop
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Pseudo-Control Hedging
Command
-
DynamicInversion
Plant
Reference Model
Actuator


Neural Network
PDControl
Tracking Error
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Communications

• Generic communication routines
• Supports serial data reading and writing
• Can re-route this data through Ethernet or as
  memory within an a single executable
• Most operating system specific software is
  limited to these routines (maybe they should
  replaced with ACE routines)
• Used for
• all onboard serial interfaces
• all GCS serial interfaces
• a redundant datalink through the wireless
  Ethernet
• Data received on a link can be saved to a file

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Data recording

• Record any onboard data at fixed rate into a
  binary file
• Can start/stop recording from GCS
• Download normally over wireless Ethernet

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Baseline GCS Software

• Monitor onboard systems
• Send reconfiguration commands
• Probe onboard data
• Initiate data recording, download data
• Set up, preview, and upload flight plan

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Available Data

• Available Onboard
• Raw Sensor Data, Pilot Inputs
• Processed Navigation Solution
• Ground Station Communication
• Available On the Ground
• Network Connection to Onboard Computers
• Available Inputs
• Desired Continuous Trajectory for Baseline
  Autopilot
• Servo Commands (If We Trust You)

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Simulation Tools

• Hardware In the Loop Simulation Capable
• The Desktop Computer Simulation Utilizes
• Actual Flight Software
• Actual Ground Control Station Software
• Flight Test Verified Dynamic Model of Helicopter
• Flight Test Verified Model of All
  Sensors/Actuators
• Scene Generation Capability

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Software in the Loop (SITL) Single CPU
Desktop Computer
Vehicle Model
Sensor Emulation (w/ Error Model)
Actuator Model
State
Control
Sensor Raw Data
Actuator Raw Data
Other Systems
Command Vector
Sensor Drivers
Actuator Driver
Sensor Data
State Estimate
Flight Controller
Navigation Filter
Control
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Hardware in the Loop (HITL) Primary Flight
Computer

• Flight software runs on the onboard computer
• Onboard computer thinks it is flying the vehicle

Desktop Computer
Vehicle Model
Sensor Emulation (w/ Error Model)
Actuator Simulation
State
Control
Sensor Raw Data
Actuator Raw Data
Sensor Drivers
Actuator Driver
Sensor Data
State Estimate
Flight Controller
Navigation Filter
Control
Command Vector
Flight Computer
Datalinks Ground Control Station
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Hardware in the Loop (HITL) Second Computer
Desktop Computer
Vehicle Model
Sensor Emulation (w/ Error Model)
Actuator Model
State
Control
Sensor Raw Data
Actuator Raw Data
Other Systems
Command Vector
Sensor Drivers
Actuator Driver
Sensor Data
State Estimate
Flight Controller
Navigation Filter
Control
Your Algorithm Here
Second Computer
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Flight Configuration (2003 SEC)
Actuator Raw Data
Sensor Raw Data
Sensor Drivers
Actuator Driver
Sensor Data
State Estimate
Flight Controller
Navigation Filter
Control
Command Vector
Primary Flight Computer
Your Algorithm Here
OCP Components
Inter-process Communication
Second Computer
Ground Control Station
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Flight Operations

• Network Connections Available At Ground Control
  Station from Hub
• Multiple Laptops Can Communicate with Onboard
  Computers Simultaneously
• Endurance Limited Only by Onboard Fuel Due to
  Generator (1 hour)
• Ground Equipment Can Operate on 115VAC or 12VDC
  and Has Battery Backup

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McDonough GA Test Field
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Race Track
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Automatic Takeoff
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Automatic Landing
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Rapid Reposition
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Automatic Aggressive Maneuver
180 Degree Velocity Change in a congested
environment
Keep nose aligned with velocity (zero sideslip)
throughout
Start and Finish at 30 Knots
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180o Velocity Change
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Pirouette
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Working on the Glider
GTMax Mother Ship
Optically Guided Glider
Video
Pan/Tilt Camera Added
Practice Structure (Wall)
Servo Commands
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Practice Video, Manual Control
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Prototype Glider Launch
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DARPA IXO Grand Challenge for Urban Operations
GTMax Mother Ship w/OAV Insertion
This is a CLOSED window!!
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Future Test Location
The circled buildings are fully instrumented
Dismounted Battlespace Battle Lab McKenna Urban
Operations Site Fort Benning, Georgia
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Simulation and Flight Testing Procedures
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Approach

• SEC University Final Exam Follows From Mid Term
• Platforms
• Components
• Develop GTMax VTOL UAV, Ground Control Station,
  and Simulation Infrastructure
• Add additional Platforms (Heterogeneous)
• Fixed Wing Aircraft
• Ground Vehicles
• Developed as an Open Experimental System
• Other Researchers Utilize Simulation Tools to
  Develop OCP Components and Test on Desktop
  Machines
• University Final Experiment supports Industry
  Final Experiment

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Summary Procedure

• Develop Test Plan
• Define and Implement Interface(s)
• SITL Simulation
• HITL Simulation
• Flight Test

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Flight Configuration (2003 SEC)
Actuator Raw Data
Sensor Raw Data
Sensor Drivers
Actuator Driver
Sensor Data
State Estimate
Flight Controller
Navigation Filter
Control
Command Vector
Primary Flight Computer
OCP Components
Inter-process Communication
Second Computer
Desktop Computer
Ground Control Station
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GTMaxLink Interface
Signal LimitInfo Position(x,y,z) Velocity(x,y,z)
Acceleration(x,y,z) Time Delf, Delm(x,y,z) Rpm
Limit Avoidance Component
50 Hz
Low Level Flight Controller, etc.
GTMaxLink Component
LimitInfo
LimitDecl
Signal LimitDeclaration AccelerationLimit(x,y,z)
Ethernet UDP Comm
UAVState
50 Hz
Mission Trajectory Planning Component
SetPoint
25 Hz
Signals UAVState SetPoint Position(x,y,z) Veloc
ity(x,y,z) Phi, Theta, Psi p, q, r
Primary Flight Computer
Secondary Flight Computer
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Issues for Discussion

• Adjustments to baseline architecture
• Hardware and software changes needed for GTMax
• Virtual Obstacles
• Interfaces defined and implemented