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CHIRP
CHIRP
Coaxial Hovering Indoor Reconnaissance Probe
Preliminary Design Review
Aerospace Engineering Department
University of Colorado, Boulder
Fall 2003
AES-CHIRP-7301
CHIRP
Group Members
Rob Beetem
•Project Manager
•System Integration Engineer Bill Pisano
•Webmaster
•Avionics Team Lead
Dave Lawry
•CFO
•Structure Team Lead
Matt Tyers
•Instrumentation Engineer
•Software Team Lead
Toby Leifer
•Safety Officer
•Electronics Team Lead
AES-CHIRP-7301
CHIRP
CHIRP
Preliminary Design Review
1.0 Project Overview
2.0 Project Objectives
3.0 Development and Assessment of Design
Alternatives
4.0 Design-to Specifications
5.0 Risk Assessment
6.0 Project Management Plan
AES-CHIRP-7301
Project Overview:
CHIRP Problem Statement
Build a slow flying craft small enough to fit
through doorways and stable enough to be
flown via onboard camera.
This aircraft will be flown by the user with
a standard RC control box.
AES-CHIRP-7301
CHIRP
Problem Solution
• In order to satisfy the slow flying
requirement, a rotating wing, hovering
design will be used.
• In order to keep the craft as small as
possible while maximizing thrust, a coaxial
rotor design will be used.
• This year the structure will be built with one
axis of augmented control.
AES-CHIRP-7301
CHIRP
Dynamic Components
• Thrust produced by rotor
system allows for vertical
lift and hover of CHIRP,
while stacked rotor
increases efficiency
• Coaxial rotor system,
opposite angular rotation
of blades cancels out net
torque and angular
momentum.
AES-CHIRP-7301
CHIRP
Project Subsystems
• Structure
– Rotor assembly, Gearbox, Frame
• Software
– Augmented Stability
• Avionics
– Rate Gyro, Accelerometer, Micro Controller, Speed Controller
• Electronics
– Electric Motor, Battery
• Payload
– Wireless Video Camera
AES-CHIRP-7301
CHIRP
Rotor System Design
• Coaxial, Counter-rotating
blades.
• Full cyclic and collective
control of bottom rotor,
collective only on top rotor.
• Requires modification of
readily available parts.
• Cyclic pitch controls craft pitch
and roll axes.
• Collective Pitch controls yaw
axis.
AES-CHIRP-7301
CHIRP
Project Objectives
• 20” Rotor Diameter
– Small enough to fit through doorways, yet large enough lift
avionics package and payload.
• 2lb total vehicle weight
– Based on models in existence, a single 20” rotor can easily lift
more than 1lb. Thus a model with two 20” rotors should be able
to lift 2lb easily.
• 5 minute minimum flight duration
– Long enough to complete basic reconnaissance missions.
• Computer Augmented Stability
– 10 – 20 Hz Bandwidth will allow for an onboard flight computer
with sensors to augment the stability of user-input controls.
AES-CHIRP-7301
CHIRP
Main Mechanical Design
• Redesigning rotor from an RC helicopter kit
into a coaxial stacked rotor system for
CHIRP
• Designing and implementing a differential,
motor and gearbox system
• Designing an airframe to contain all
components in CHIRP
AES-CHIRP-7301
CHIRP
Main Avionics Design
• Integrate yaw and translation sensors for the
purpose of determining flight perturbations
• Integrate microcontroller to process user
commands and sensor inputs
• Develop control algorithms to produce one
axis of stability
AES-CHIRP-7301
CHIRP
NEW DESIGN FEATURES
Coaxial Stacked Rotor
Differential
Airframe Structure
AES-CHIRP-7301
CHIRP
Stand for 1-Axis Testing
AES-CHIRP-7301
Development & Design Alternatives:
CHIRP Power vs. Area
Single rotor lift Stacked rotor lift
T 2 A1Vi1
2
T 2 (2 A1 )Vi2
2
• Induced velocity, “downwash” air • Power is proportional to the
going through top of rotor. downwash velocity, as shown in
the equations below.
• An increase in area decreases the
T
Vi power consumption
2 A
1
• Power Consumption, only work P V P
done in hover is the change in
kinetic energy of the air.
A
1
P TVi1
1
P2
2 A1
.707 P1
AES-CHIRP-7301
CHIRP
Axis Control: Cyclic vs. Vanes
• Cyclic: control comes • Vanes: Control comes
from blade pitch from vertical vanes
• Control Axis inserted into the down
Decoupling simplifies wash
control system • Simplifies mechanical
• Lower structural design
weight • Higher demand on
• More complex Microcontroller
mechanical design • Higher weight
AES-CHIRP-7301
CHIRP
Yaw Axis Control
• The yaw axis will be controlled by
changing the relative amount of drag on
the two rotors. More drag on one than the
other causes a net moment on the craft in
the direction of the higher drag force.
AES-CHIRP-7301
CHIRP
Yaw Axis Control
• Option 1: Fixed Pitch
Upper Rotor.
– Mechanically simple to
design and build.
– Causes coupling of yaw
and thrust controls.
• As yaw rate is changed,
the net thrust vector
changes due to the
change in pitch of the
lower blades.
• Would require mixing
of inputs and/or active
stabilization in the
translational z-axis.
AES-CHIRP-7301
CHIRP
Yaw Axis Control
• Option 2: Collective Pitch Upper Rotor
– Change the collective pitch of the upper rotor
in the opposite direction of the lower, thus
canceling the net change in thrust
• More involved mechanically from a design and
build standpoint.
• Decouples thrust and yaw control axes, allowing
for a simplified control system.
AES-CHIRP-7301
CHIRP
Yaw Axis Control
• Possible Designs for
collective pitch upper rotor
system:
1. Fix upper blade hinges with
respect to outer shaft, move
entire inner shaft assembly
to control collective pitch.
– Requires several slip
bearings and gears, which
complicates the design.
2. Pass a pushrod through
center of inner shaft.
– Relatively simple design.
– Increased torsion load on
inner shaft.
AES-CHIRP-7301
CHIRP
Rate Gyro Options
Sensor Type Company Part Number Performance Cost Size / Weight Availability
Futaba GY240 / GY401 Average Average Large Average
Model Helicopter
Yaw Gyro
JR G460T SPORT Tail Average Average Large Average
Lock Gyro
Analog Devices ADXL150 Excellent Low Small Average
MEMS
Rate Gyro
U.S. Dynamics 446 rate integrating Excellent Average Small Average
Corporation gyro
Honeywell GG400 GNAT Excellent High Large Low
Commercial / International miniature rate gyro
Military Rate Gyro
Crossbow DMU FOG-VG Excellent High Large Low
AES-CHIRP-7301
CHIRP
Accelerometer Options
Sensor Type Company Part Number Performance Cost Size / Weight Availability
Analog Devices ADXL 105 Excellent Low Small Average
Piezoresistive
(MEMS)
Accelerometers
ENDEVCO 7269-500 Excellent Average Small Average
Honeywell QA650 Q- Excellent High Large Low
Commercial / International Flex
Military
Accelerometer
Crossbow CXL04LP1 Excellent High Large Low
AES-CHIRP-7301
CHIRP
Avionics Package Options
Design
Options Manufacturer Comments Risk Performance Flexibility Weight Cost
Automatic control input
gyro Futaba Will likely need 3 low mod low high high
Microcontroller: Basic separate chip for
Stamp Parallax PWM mod high high low mod
need to build
computer link
Microcontroller: PIC Microchip hardware mod mod high low low
AES-CHIRP-7301
Video Camera Options
CHIRP
Company Model Frequency Range Power Supply Total Weight Cost
Wireless Video HLF11 2.453GHz 1100 feet AA Batteries 14 oz Low
Cameras. com external case
RC MiniCam NTSC TX-RX 2.4GHz 1000 feet RC Receiver 1 oz Low
Eyecam D-EYECAM 2.4GHz 1000 feet RC Receiver 1 oz Low
AES-CHIRP-7301
Design-To Specifications:
CHIRP
Rotor System
• Coaxial, Counter-
rotating blades.
• 20” rotor diameter.
• 2lb total weight.
• 5 minute flight duration
• 3-shaft design.
• Full cyclic and
collective control of
bottom rotor, collective
only on top rotor.
AES-CHIRP-7301
CHIRP
Power and Drive system:
• Light weight, brushless, high torque
motor
• Gear box: 20:1 gear ratio for
optimum power output
• Lightweight ball differential for
counter rotating blades
• Hollow main rotor shaft and inner
shaft riding on bearings.
AES-CHIRP-7301
CHIRP
Current Avionics Study
• ADXRS 150 MEMS Angular Rate Gyro
• ADXL 105 MEMS Accelerometer
• Micro Controller undecided
• Working with additional groups to develop on
board controller to work with all projects
AES-CHIRP-7301
CHIRP
Avionics Package Block Diagram
Scale Factors
User Actuator
User Input Communication Link For Interrelated
Commands
Motions
Physical Motion Servo
Actuators
Scale Factors
Onboard Corrective Actuator
(vary with desired
Rate Gyros Commands
damping)
Inputs
Internal commands
Flight computer
Physical
AES-CHIRP-7301
CHIRP
Battery and Motor
• Estimates for power are based on the power equations, plus
a safety factor:
– Motor must supply up to 150 watts to stacked rotor system for
CHIRP to hover and climb vertically
• The battery must supply enough power to operate the
motor and the avionics, this is based on:
– Current draw from motor and time constraint
Battery ( Ahr )
.2hrs 5 min
amp _ draw _ from _ motor( A)
– Power needed for avionics based on specifications for each avionic
component
AES-CHIRP-7301
CHIRP
User Controls
•Futaba 9CHP FM Transmitter
•HI-TEC 6 channel receiver
AES-CHIRP-7301
CHIRP
Payload Selection
• RC MiniCam, NTSC TX
• 2.4GHz Micro Transmitter
• Color CMOS Camera
• Camera and transmitter
weight less than 1 oz.
• Range: 1000 feet
• Size: 15mm x 22mm x
32mm
AES-CHIRP-7301
CHIRP
Weight and Power
Weight Distribution
Last Modified 10/5/03
System Subsystem Weight (ounces)
Airframe 15
Structure 6
Rotor Assembly 3 Power Comsumption
Blades 2.4 Last Modified 10/5/03
Shafts 2.7
System Subsystem Power
Electronics 4
Rate Gyro 0.02 Electronics
Accelerometer 0.02 Motor 150 W
Micro Controller 0.5
Speed Controller 0.1 Avionics
Servos 0.22 Rate Gyro 30 mW
Reciever 0.7 Accelerometer 3.5 mW
Wires 0.5 Micro Controller 720 mW
Speed Controller 5 mW
Engine 4 Servos 300 mW
Motor 3 Reciever 95 mW
Gearbox 1
Payload
Power 10 Camera 1W
Battery 10.8
Total Power Consumption 153 W
Payload 5
Camera 0.5
Transmitter 0
Wires, antenna
Allowed Weight (oz) 38
Actual Flight Weight (oz) 31.46
AES-CHIRP-7301
CHIRP
Function of Test Stand
• Stand limits degrees of
freedom
• Limited to the z-axis and
yaw-axis
• Simplifies testing control
system for CHIRP
• Safety Protection during
testing and verification
phase
AES-CHIRP-7301
CHIRP
Risk Assessment: Drive Train
• Risks • Off Ramps
– Differential – Differential can be built
• New conceptual design using two motors at the
– Rotor Heads expense of weight
• Redesigning stacked rotor
head to allow for coaxial – Top rotor can be set as fixed
collective control, top and pitch
bottom rotor
– Vanes set in downwash can
be designed and
implemented to replace
cyclic control
AES-CHIRP-7301
CHIRP
Avionics Package Risks
• Risks • Off Ramps
– Integration of Avionics – Use off-the-shelf
Package
– Develop hardware
– Successful Control
Program for future use,
incorporate off-the-
shelf hardware
AES-CHIRP-7301
CHIRP
Power System Risks
• Risks • Off Ramps
– Power Consumption: – Upgrade motor and
• Initial estimates based battery systems
on theory, could give
unrealistic values – Downgrade to
– Not enough power- lighter, less
doesn’t fly powerful motor or
– Too much power–
weights too much
battery
– Tethered power
source
AES-CHIRP-7301
CHIRP
Project Management
AES-CHIRP-7301
CHIRP
Organizational Chart
Advisors:
Prof. Lawrence CHIRP Project
Project Manager: Advisory
Dale.Lawrence@colorado.edu
Rob Beetem Board
Prof. Axelrad beetem@colorado.edu
Penina.Axelrad@colorado.edu
Instrumentation
Engineer: Webmaster: Safety Officer: Chief Financial Officer:
Matt Tyers Bill Pisano Toby Leifer Dave Lawry
William.Pisano@colorado.edu Toby.Leifer@colorado.edu David.Lawry@colorado.edu
Matthew.Tyers@colorado.edu
System Integration
Engineer
Rob Beetem
Structure 3.2 Software 3.3 Payload 3.6
Dave Lawry Avionics 3.4 Electronics 3.5
Matt Tyers Rob Beetem
Toby Leifer Bill Pisano
Bill Pisano Toby Leifer
Matt Tyers Dave Lawry
Rob Beetem
Rob Beetem
AES-CHIRP-1111
AES-CHIRP-7301
CHIRP
Work Breakdown Structure
CHIRP
1.0 Project Mgmt 2.0 System Engr 3.0 Design 4.0 Fabrication 5.0 Integration 6.0 Testing 7.0 Reporting
1.1 Planning 2.1 Objectives 3.1 Planning 4.1 Structure 5.1 Planning 6.1 Planning 7.1 Reports
1.2 Task Mgmt 2.2 Concepts 3.2 Structure 4.2 Software 5.2 Hardware 6.2 Structure 7.2 PDD
1.3 Financial 2.3 Analyses Cpts 3.3 Software 4.3 Electronics 5.3 Avi & Soft 6.3 Software 7.3 PDR
2.4 Reqts Spec 3.4 Avionics 4.4 Avionics 5.4 System 6.4 Avionics 7.4 CDR
3.5 Electronics 6.5 Electronics 7.5 Final Report
3.6 Payload 6.6 Payload
3.7 Test Stand
AES-CHIRP-7301
CHIRP
Work Breakdown Structure
3.2 Structure
CHIRP Work Breakdown Structure 3.2.1 Structural Layouts
Last Modified: 10/05/ 2003 3.2.2 Computer analysis of design
AES-CHIRP-1121 3.2.3 Material Selection
3.2.4 Integration of Subsystems
WBS Activity Name Responsibility 3.2.5 Analysis and changes to system
1 Project Management
1.1 Planning and Schedule 3.3 Software
1.1.1 Organizational Chart RB 3.3.1 Basic software layout
1.1.2 Work Breakdown Structure RB 3.3.2 Flow chart of system
1.1.3 Tasks and Action Items RB 3.3.3 Software utilized
1.1.4 Numbering System RB 3.3.4 Integration of software and elect.hardware
1.1.5 Drawing Tree RB 3.3.5 Computer Simulation of software/hardware
1.2 Task Management 3.3.6 Analysis and changes to system
1.2.1 Task Assignments RB
1.2.2 Weekly Meetings RB 3.4 Avionics
3.4.1 Basic hardware layout
1.3 Financial Management 3.4.2 Flow chart of system
1.3.1 Budget Projections RB 3.4.3 Hardware utilized (gyros, accel)
1.3.2 Actual Budget Spent DL 3.4.4 Integration of hardware and software
3.4.5 Test of vital components
2 System Engineering 3.4.6 Power comsumption
2.1 Project Objectives 3.4.7 Analysis and changes to system
2.1.1 Defiination of Project Objectives CHIRP
2.1.2 Feasibility of Objectives CHIRP 3.5 Electronics
3.5.1 Basic Electronics layout
2.2 Concepts 3.5.2 Flow chart of system
2.2.1 Development of Concepts CHIRP 3.5.3 Components utilized (batt, motor)
3.5.4 Integration in to structure
2.3 Analysis of Concepts 3.5.5 Power and duration availiable
2.3.1 Feasibility of Concepts CHIRP 3.5.6 Test of vital components
2.3.2 Detailed analysis of Concepts CHIRP 3.5.7 Analysis and changes to system
2.4 Requirements and Specification Definition 3.6 Payload
2.4.1 Outline of Requirements CHIRP 3.6.1 Choice of payload package
2.4.2 Final Specifications CHIRP 3.6.2 Integration design of payload
2.4.3 Weight Table by Subsystem RB
3 Design 4 Fabrication
3.1 Planning 4.1 Structure
3.1.1 Distribution of Tasks RB 4.1.1 Material Seletion
3.1.2 Structure of Design Process RB 4.1.2 Design of components
4.1.3 Special Fabrication Needs
4.1.4 Actual Fabrication Techniques
4.1.5 Analysis of Design
AES-CHIRP-7301
CHIRP
Detailed Schedule
AES-CHIRP-7301
CHIRP
Preliminary Schedule
AES-CHIRP-7301
CHIRP
Drawing Tree
CHIRP Drawing Tree
Last Modified: 10/5/03
AES-CHIRP-1150
Drawing Dates Financial
Drawing Number Drawing Name Quantity Start Time Required Finished Make/Buy Unit Cost $ Total Cost$
AES-CHIRP-D32116 Fixed Pitch Upper Rotor Assembly 1 9/23/03 10 days 10/3/03 - - -
AES-CHIRP-D32117 Collective Pitch Upper Rotor Option 1 1 9/23/03 10 days 10/3/03 - - -
AES-CHIRP-D32128 Collective Pitch Upper Rotor Option 2 1 9/23/03 10 days 10/3/03 - - -
AES-CHIRP-D32100 Inner Collective Head Assembly 1 9/23/03 10 days 10/3/03 $300.00 $300.00
AES-CHIRP-D32101 Outer Shaft 1 9/23/03 10 days 10/3/03 Buy - -
AES-CHIRP-D32102 Inner Shaft 1 9/23/03 10 days 10/3/03 Buy - -
AES-CHIRP-D32103 Collective Push Rod 1 9/23/03 10 days 10/3/03 Buy - -
AES-CHIRP-D32104 Swash Plate 1 9/23/03 10 days 10/3/03 Buy - -
AES-CHIRP-D32105 Lower Head Joint 1 9/23/03 10 days 10/3/03 Make - -
AES-CHIRP-D32106 Upper Head Joint 1 9/23/03 10 days 10/3/03 Make - -
AES-CHIRP-D32107 Blade Clamp 4 9/23/03 10 days 10/3/03 Buy - -
AES-CHIRP-D32108 Rocker 2 9/23/03 10 days 10/3/03 Buy - -
AES-CHIRP-D32109 Inner Gimbal 1 9/23/03 10 days 10/3/03 Make - -
AES-CHIRP-D32110 Outer Gimbal 1 9/23/03 10 days 10/3/03 Make - -
AES-CHIRP-D32111 Averaging Hinge 1 9/23/03 10 days 10/3/03 Buy - -
AES-CHIRP-D32112 Main Blades 4 9/23/03 10 days 10/3/03 Buy - -
AES-CHIRP-D32113 Fly Bar Blades 2 9/23/03 10 days 10/3/03 Buy - -
AES-CHIRP-D32114 Fly Bar 2 9/23/03 10 days 10/3/03 Make - -
AES-CHIRP-D32115 Upper Collective Joint 1 9/23/03 10 days 10/3/03 Make - -
AES-CHIRP-D32300 Differential 1 9/26/03 5 days 10/1/03
AES-CHIRP-D32301 Ball Differential 1 9/26/03 5 days 10/1/03 Buy $26.00 $26.00
AES-CHIRP-D32302 Bearings 2 9/26/03 5 days 10/1/03 Buy $5.00 $10.00
AES-CHIRP-D32303 Small Gears 2 9/26/03 5 days 10/1/03 Buy $5.00 $10.00
AES-CHIRP-D32304 Large Gears 2 9/26/03 5 days 10/1/03 Buy $10.00 $20.00
AES-CHIRP-D32500 Structure 1 10/7/03 8 days 10/15/03 Make
AES-CHIRP-D32501 Skeleton Frame 1 10/7/03 8 days 10/15/03 Make $200.00 $200.00
AES-CHIRP-D32502 Gear Box 1 10/7/03 8 days 10/15/03 Make $46.00 $46.00
AES-CHIRP-D32503 Avionics Package 1 10/7/03 8 days 10/15/03 Make $200.00 $200.00
AES-CHIRP-D32504 Battery 1 10/7/03 8 days 10/15/03 Buy $100.00 $100.00
AES-CHIRP-D32505 Motor 1 10/7/03 8 days 10/15/03 Buy $200.00 $200.00
AES-CHIRP-D32506 Reciever 1 10/7/03 8 days 10/15/03 Buy $120.00 $120.00
AES-CHIRP-D32507 Payload 1 10/7/03 8 days 10/15/03 Make $250.00 $250.00
AES-CHIRP-D37400 Test Stand
AES-CHIRP-D37401 Base 1 9/23/03 10 days 10/3/03 Make $10.00 $10.00
AES-CHIRP-D37402 Bearings 2 9/23/03 10 days 10/3/03 Buy $10.00 $10.00
AES-CHIRP-D37403 Rod 1 9/23/03 10 days 10/3/03 Buy $15.00 $15.00
AES-CHIRP-D37404 Pulley 1 9/23/03 10 days 10/3/03 Buy $10.00 $10.00
AES-CHIRP-D37405 Weight 1 9/23/03 10 days 10/3/03 Make $5.00 $5.00
AES-CHIRP-D32600 Payload
AES-CHIRP-D32601 Camera 1 10/7/03 8 days 10/15/03 Buy $250.00 $250.00
AES-CHIRP-D32602 Mount for Camera 1 10/7/03 8 days 10/15/03 Make $20.00 $20.00
AES-CHIRP-7301
Expected Project Costs
CHIRP
Cost Estimates
Last Modification: 10/5/03
AES-CHIRP-1311
System Subsystem Number of Units Unit Cost Total Cost System Subsystem Number of Units Unit Cost Total Cost
Airframe Electronics
Rotor System Kit 1 165.00 165.00 Motor 1 200.00 200.00
Rotor Head 1 80.00 80.00 Servos 3 30.00 90.00
Propellers 2 60.00 120.00 Battery 100.00 100.00
Gear Box
Ball Differential 1 26.00 26.00 Users Control
Bearings 2 5.00 10.00 Transmitter 1 380.00 380.00
Small Gears 2 5.00 10.00 Reciever 1 120.00 120.00
Large Gears 2 10.00 20.00
Payload
Structure Camera 1 250.00 250.00
Drive Sharft 2 30.00 60.00 Test Stand
Structure 1 200.00 200.00 Base 1 10.00 10.00
Bearings 1 10.00 10.00
Rod 1 15.00 15.00
Software Pulley 1 10.00 10.00
0 0.00 0.00 Weight 1 5.00 5.00
Avionics
Rate Gyro 1 50.00 50.00 Total Cost: 2071.00
Accelerometer 1 30.00 30.00
Micro Controller 1 60.00 60.00
Speed Controller 1 50.00 50.00
AES-CHIRP-7301
CHIRP
Questions
AES-CHIRP-7301
CHIRP
Avionics Package
Design Issues and Risk
(Once Integration and Software is Ascertained)
Sensors
• Vibrations
Mechanical Damper
• Drift
Low flight duration
Software/Microcontroller
• Program cycle catching rapid perturbations
Capability of 25 – 50 MHz processor
AES-CHIRP-7301
CHIRP
Thrust in Vertical Climb
• Single rotor lift • Stacked rotor lift is
A doubled
T 2 (Vc Vi )Vi
A
2 T 22 (Vc Vi )Vi
• Induced velocity decreases
2
as climb speed increases • Power Consumption,
Vh (Vc Vi )Vi
2 consists of work done by
rotor thrust in climb and
2
Vi Vc Vc on air (kinetic energy of
2V 1
rotor downwash) TVc TVi
Vc 2Vh h
P 2T (Vc Vi )
AES-CHIRP-7301
CHIRP
ADXRS 150 MEMS Angular Rate
Gyro
• Micro Electrical
Mechanical System
(MEMS)
• Single Chip Rate
Gyroscope
• Z-axis response
• Angular Rate:150 deg/sec
• Voltage: 5V
• Size: 7mm x7mm x 3mm
AES-CHIRP-7301
CHIRP
ADXL 105 MEMS Accelerometer
• Single Axis
• Range: ±5g
• Bandwidth: 10kHz
• Low Power: 2mA
• Voltage Range: 2.7 to 5V
• Size: 11mm x 11mm x 4mm
AES-CHIRP-7301
CHIRP
Basic Subsystem Layout
AES-CHIRP-7301
