Transcript SOARS

SOARS
Self Organizing Aerial Reconnaissance System
Critical Design Review
ASEN 4018 Senior Projects
11/15/06
Matt Edwards
Arseny Dolgov
John Shelton
Johnny Jannetto
Galina Dvorkina
Nick Driver
Eric Kohut
Kevin Eberhart
1
Presentation Outline
• Overview and Objectives
• System Architecture
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Objectives
Requirements
System Design
Expected Performance
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Project Overview
•
Objective: Design, build and test an autonomous aerial system (UAS)
capable of imaging multiple targets within a 1km circle as quickly as
possible with 99% probability of object detection (according to Johnson
criteria).
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AFRL COUNTER Project
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Optimal imaging altitude <100m for a small aerial vehicle
Minimize risk to larger master vehicle
Master
GPS Coordinates,
Heading
Truck
Slave
hmax = 70 m
Ground Station
1. AFRL COUNTER Project. Used with permission.
Target
(X,Y,Z)
3
Test Scenario
4
Requirements Overview
• Image at least 3 targets, satisfy Johnson Criteria
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Time: <8 minutes
Flying distance: >4 km
• Slave UAV >1km radius of operation in relation to stationary
(assumed) Master vehicle
• New critical requirement:
•
Image lag < 2 seconds from slave to ground-station
• Targets given by GPS location and heading from ground
station
• Slave UAV
• Max weight: 1.5kg
• Maximum width for below-wing mounting:
120 cm
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Requirements Detail
Slave Vehicle
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Telemetry/Images Sent over >1km to Master
Delay to receiving image: <2sec
>3 Targets imaged, satisfying Johnson Crit.
< 10% Image Blur
Travel at least 4km in 8 minutes
Autonomous navigation to GPS coord, heading
Deployable from SIG Master vehicle
Ground Station
Master Vehicle
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Relay 640x480 images in <2 sec
RF Link endurance >20min
>2km range to Ground Station
Manually Piloted RC
Must be able to carry Micropilot module
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Slave telemetry update rate: 1Hz
Identify image w/ location and timestamp
Send target (GPS, heading) commands to
slave via master
Range to Master: >2km
Receive 640x480 images in <2 sec
Graphical User
Interface
Avionics
Control
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Pitch within 30°
Rate < 12°/s
Data relay, >250kbps
< 2 sec delay
GPS XY Input
Heading Input
Roll within 30°
Rate < 115 °/s
Must fit inside 5x10x5
cm box
Display 640x480 image
Heading within 30°
Rate < 12°/s
Range: >2km
Position accurate to
10m
Communications
Bandwidth
>250kbps
Display slave telemetry:
position, velocity
Communications
Power
> 20 min operating
time for avionics/
comm subsystem
Receive Data at 1Hz
Range >2km
<2 seconds image
delay
Bandwidth >250kbps
Control Software
Power
Range > 4km
Speed > 30km/h
GS-Master Handshaking
Ensure slave receives
command
Imaging
Resolution >600lines
30° < FOV <60°
Working Distance
<90m
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Deliverables
Fully loaded take-off and deployment of
two slaves. Advanced flock management.
Future COUNTER Mission
Increasing Complexity
Demonstrate ground-deployment of
slave.
Demonstrate “theoretical” slave
deployment capability w/ designed
mechanism.
As below, but coordinates and pictures
relayed through master vehicle.
Slave flies to and loiters above any target
specified by GS and sends back pictures.
Slave loiters above preprogrammed
target, acquiring images.
Target System
• Selection of slave vehicle
• GS to Master to Slave RF link
• Image reception
• Target specification
• Demonstrate <2 sec image
delay
• Slave telemetry (GPS position,
altitude, heading, speed)
• 3 Images taken with correct
position, attitude (Johnson criteria)
• Autonomous navigation
• Deployment feasibility
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System Architecture: Slave
•Slave requires custom interface and power board to house camera and
send data to CU Autopilot.
•Custom autopilot and controls software will be developed to meet target
imaging requirements.
SLAVE VEHICLE
1000mAh
LiPo Battery
Daughter Board
CMOS JPEG
Camera
PCB
Design
& Fab
3.3 V
Regulator
Level Shift
115kbps Asynch
CU Autopilot
Power Subsystem
Rate Gyro
Processing Element
Communications
PIC Microcontroller
Control Software
Altimeter
GPS
Receive Buf
Send Buf
Short-Range ZigBee
Transceiver, 250kbps OTR
TO MASTER @ 2.4Ghz
Servos
ESC
Motor
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System Architecture: Master
•Master houses two COTS radios
•1 long-range point-to-point (for communication with ground-station)
•1 short-range multipoint (for communicating with multiple networked slaves)
•CU autopilot provides data for verification, maintains master UAV loiter
•Custom microcontroller software handles command dispatch and data/telemetry
MASTER VEHICLE
Motor
CU Autopilot
Power Subsystem
PIC Microcontroller
Stock Software
Processing Element
Communications
1000mAh
LiPo Battery
ESC
Servos
Microcontroller – PIC18F8722
Control
Software
3.3V
Regulator
5.0 V
Regulator
PCB
Design
& Fab
800kbps Asynch
Send Buf
Receive Buf
Long Range Radio
Modem, 800kbps OTR
TO GROUND STATION @ 2.4 Ghz
UART0
UART0
Receive Buf
Receive Buf
Send Buf
Send Buf
250kbps Asynch
Level Shift
Receive Buf
Send Buf
Short-Range ZigBee
Transceiver, 250kbps OTR
TO SLAVES @ 2.4Ghz
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System Architecture: Ground Station
•Ground station houses 1 long-range radio for sending commands to master
•Custom microcontroller and software interface to PC graphical interface
•GUI allows user to enter target location, issue commands
•Image display
Power Subsystem
Processing Element
GS Board
Communications
USB Power
Microcontroller – PIC18F8722
5.0 V
Regulator
PCB
Design
& Fab
250kbps Serial to USB
Converter
Control
Software
UART0
UART1
Receive Buf
Receive Buf
Send Buf
Send Buf
800kbps Asynch
Send Buf
Receive Buf
Long Range Radio
Modem, 800kbps OTR
Target Location Input
Heading Input
TO MASTER @ 2.4Ghz
PC Interface
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Slave Component Layout
Rate Gyro
GPS Antenna
RC Receiver
ZigBee Radio
2.4GHz RF Antenna
Camera Mount Under Wing
ESC
LiPo Battery Pack
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Master & Slave Mounting
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Autopilot Control Method
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Lyapunov vector field used for navigating to designated target at desired GPS
location and heading.
Custom autopilot code will use roll rate-gyro and GPS for heading control
Altitude hold to be implemented with pressure altimeter. Elevators and thrust
used for altitude control.
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Software Design
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Interrupt-driven operation ensures
that both radios are serviced by
master vehicle
Master waits for input from
radios, receives commands
• Retransmits commands
to slaves
• Sends back images,
telemetry
Baud Rate
Parity
Data Bits
Init UART0
Init UART1
Address
Packet Size
Power, etc
Setup SR ZigBee
Address
Packet Size
Power, etc
Setup LR Modem
Power-On
Enable UART0/
UART1 Interrupt
IDLE
GS Receive Interrupt Service
Routine
Slave Receive Interrupt Service
Routine
UART0 Receive
(GS)
Parse out packet
UART1 Receive
(Slave)
Slave ID
Target Spec:
XYZ, H
Data Packet
(imagery, etc)
Ready to
send?
YES
Perform
computation/make
decision??
Transfer Data to
UART0
Ready to
send?
YES
Transfer Data to
UART1
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Expected Performance
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Imaging
Aircraft
Communications
Autopilot
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Imaging Performance
• 640x480 JPEG compression camera
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6 lines of resolution within target (meets Johnson criteria) at 100m range
60° FOV leaves >30° margin in pitch, roll and yaw
• Plots show that maximum perpendicular
velocity during approach < 20m/s.
• At this speed, camera blur is well below 10%
Plot of Velocity
300
30
Perpendicular Velocity
Tangential Velocity
20
250
=
about 20 m/s
10
200
t =
t =
150
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0. 00
Velocity (m/s)
Maximum Tangential Velocity (m/s)
t
07
0. 0
0. 011
about 10 m/s
0
-10
. 013
t = 0
100
-20
-30
-100
50
0
0.1
0.2
0.3
0.4
0.5
Blur Factor
0.6
0.7
0.8
0.9
1
-80
-60
-40
-20
0
20
40
60
80
100
Range to Target (m)
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Communications Performance
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Communications subsystem must ensure <2 seconds image propagation
delay
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Current system limited by image retrieval speed from camera
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Camera outputs 16kbyte JPEG images
Slowest link in system must be >115kbps
115kbps bottleneck in camera interface
No other camera available with built-in JPEG compression
Most cameras output RAW format in 8-bit parallel, image size too big (>400kbytes)
Communications system has large margin (250kbps minimum data rate) to
leave room for protocol overhead, errors and dropped packets
Ground Station
Slave Vehicle
Master Vehicle
800kbps
250kbps
Radio
Radio
Radio 1
Radio 1
500kpbs
500kpbs
MCU
500kpbs
500kpbs
MCU
MCU
250kpbs
115kpbs
Graphical User Interface
Camera Module
Image Path Delay < 2 seconds
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Autopilot Performance
•Use of custom Lyapunov field for pointing and direction control (simulation
below)
•Vector field center can be adjusted to switch to different targets
•Simulation results show that particle traveling at 20m/s is guided to within 30°
of target heading on approach, and particle passes directly overhead of target.
projected path of particle in slave vector field starting (0 -300)
200
100
y position
0
-100
-200
-300
-400
-500
-100
-50
0
50
100
150
200
x position
250
300
350
400
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