Autonomous Rendezvous SystemCapstone Design Proposal

Chase DavisDaniel PhiferNimesh PatelReNina FieldsLarry Lybrook

Rachael GreenMatthew WrightEric KneynsbergJimmy Simmons

University of Alabama Department of Electrical and Computer Engineering1

Problem statement Background

information Possible overall

solutions Plan of action Detailed specifications

◦ Platform◦ Wireless communication◦ Image processing◦ Navigation◦ Control console

Documentation Validation plan General schedule and

budget Safety and

environmental impact

2

Presentation Agenda

Chase vehicle is to rendezvous with target given starting requirements:◦ The x and y position for

the chase vehicle is x = sqrt(9-y^2)

◦ The angle of incidence, Ɵ, is such that -tol < Ɵ < tol The tolerance will be

determined once the infrared sensors have been tested

◦ The yaw is equal to Ɵ (front of vehicle pointing at target)

Rendezvous is considered successful when:◦ ∆X = 2 inches◦ ∆Y = ± 2.00 inches◦ ∆Yaw = ± 8.00 degrees

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Problem Statement

Three space stations◦ Skylab◦ Mir◦ International Space Station

Mir collision Automated Transfer Vehicle

(ATV) May 8th , 2007 Autonomous

Space Transport Robotic Operations (ASTRO)

Background

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3-Dimensional problem◦ Orbital rendezvous and

docking◦ 6 degrees of freedom

2-Dimensional problem◦ Capstone Fall 2007◦ 3 degrees of freedom

Background

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Triangulation ▣◦ Received/transmit signal strength of wireless modules◦ Very high precision and accuracy

Camera only◦ Enables a high degree of precision◦ Computationally expensive

IR sensors and compass only◦ Cheap◦ Easy to configure◦ Not accurate enough for the precise mechanics involved

in docking

Possible Overall Solutions

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IR sensors, compass and a camera Phase 1 ▣

◦ IR sensors and compass provide a coarse but fast way of zeroing Y and Yaw

◦ Move chase vehicle 2 feet out from stationary target (2,0,0)

Phase 2◦ Camera provides the needed precision to approach the

target carefully, slowly, and with enough accuracy to rendezvous/zero X

◦ Chase vehicle slowly approaches stationary target from its position 2 feet away

Overall System

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System Overview

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Target

Computer

Chase Vehicle

Microcontroller

Compass

Camera

IR Sensors

`

Microcontroller

Compass

Three modules:

Chase Vehicle Computer Target Five sub-systems

◦ Platform◦ Wireless communication◦ Image processing◦ Navigation◦ Control console

Plan of Action

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Develop each sub-system completely independent of other sub-systems

Integrate each sub-system into the overall system◦ Modify the sub-system to ensure proper interaction with

the other sub-systems and module Test, validate, and refine the system

◦ Validate the performance of each sub-system◦ Validate the proper interaction between sub-systems◦ Validate the overall system performance

Plan of Action

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Sub-system Communication

Image Processing

Control Console

Navigation

Wireless Communication

Platform

Camera image processing commands

Target image information

Movement commands

Chase vehicle position

Chase vehicle command

Chase vehicle

command

Chase vehicle position

RS-232

TTL UART

PWM

Chase◦ TK1 Basic Kit◦ Palm Pilot Robot Kit (PPRK)◦ Octabot

Wheel position◦ Scooterbot II

Wheeled Servo driven Two 7” diameter decks Cost $59.95

Target◦ Façade◦ Possibility of docking

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Platform Possibilities

Y-axis view X-axis view

Chase◦ Testing done using microcontroller pulse width modulation

(PWM)◦ Movement

• Clockwise• Counter clockwise• Forward• Reverse

◦ Speed• Five different speeds

◦ Effects of overall equipment weight Target

◦ Contingent on dockingGroup Members: Eric Kneynsberg, Larry Lybrook, Nimesh Patel,

Daniel Phifer

Platform Testing Plan

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Chase Target

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Power Budget

Component Current (mA)

Microcontroller 100*

Wireless 100*

Compass 15

Long Range IR Sensor

50

Short Range IR Sensor

50

Servos 1500*

Camera 200*

TOTAL 2015 mA

Component Current (mA)

Microcontroller 100*

Wireless 100*

Compass 15

TOTAL 215 mA

* Measured in Lab

XBee-PRO Starter Kit◦ 60 mW output power◦ 1-mile range◦ RS-232 & USB development

boards◦ 2 OEM RF modules◦ Cost $179.00

XBee Starter Kit◦ 1 mW output power◦ 100 ft. indoor range◦ RS-232 & USB development

boards◦ 2 OEM RF modules◦ Cost $129.00

Since 3 modules and development boards are needed, and the XBee Starter Kit only provided 2 of each, 1 more module and board will be purchased

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Wireless Kit Possibilities

Performance◦ Power output: 1mW◦ Indoor range: Up to 100 ft

Baudrate◦ Interface baudrate: 115,200 ◦ Operating frequency: 2.4 GHz

Networking◦ Networking topology: peer-to-peer, point-to-point &

point-to-multipoint Error handling

◦ Retries and acknowledgements

XBee Starter KitDetailed Specifications

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Simultaneously send data from control console and target to chase vehicle

Send data from chase vehicle to target and control console

Look for a proper transition on chase vehicle between control console channel and target channel

Group Members: Rachael Green, Daniel Phifer, ReNina Fields

Wireless Testing Plan

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Terasic TRDB_DC2◦ Not useable with

microcontroller CMUCam1 - $109

◦ Low resolution CMUCam3 - $239

◦ High price, unneeded functionality

CMUCam2 - $179◦ Compromise in price and

image resolution◦ Available for immediate

testing

Image Processing Possibilities

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Test for most effective beacon◦ Contrasting printed image◦ LEDs

Test color tracking function◦ Distance from beacons◦ Angle of incidence◦ Camera/beacons in motion

Test distance measurement◦ Assume 90° incident angle◦ Resolution◦ Repeatability

Group Members: Matt Wright, Jimmy Simmons, Rachael Green, Nimesh Patel

Image Processing Testing Plan

Camera – CMU Cam 2 IR sensors

◦ Infrared “ranger” sensors will help find the target◦ Operating supply voltage of 4.5 to 5.5 Volts◦ Long range IR - Sharp GP2Y0A02YK $12.50

8” to 60” range◦ Short range IR – Sharp GP2D120 $12.50

1.5” to 12” range Compass

◦ Devantech R117 $52.00◦ Dinsmore compass $14.00

Optical sensors◦ Still researching ~$1.08

Navigation

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Navigation Possibilities Altera Cyclone II FPGA

Starter Development Kit◦ Computation power◦ Learning curve◦ Price $150.00

Adapt9S12E128 Basic Module with 112-pin MCU◦ Equipment and language

familiarity◦ Size◦ Price $83.00◦ Limited memory

IR sensors◦ Test and validate ranges and detection surfaces

Compass◦ Compare readings from compass against an analog

compass to test accuracy and precision

Group Members: Eric Kneynsberg, Matt Wright, Jimmy Simmons, ReNina Fields, Chase Davis

Navigation Testing Plan

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C#◦ Better visuals◦ More elegant and

efficient design◦ Stand-alone program◦ Need .NET Framework

LabView◦ Very fast data acquisition

(DAQ)◦ Numerous powerful

functions◦ Learning curve◦ Expensive DAQ modules◦ Not stand-alone

MatLab◦ Excellent math and

graphing capabilities◦ Image processing

toolboxes◦ Slower processing◦ Not stand-alone

Control Console Possibilities

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Matlab ◦ Powerful math and

graphical functions which allows for future upgrades

◦ Slower processing is not detrimental

◦ Reduced learning curve

Control Console Solution

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MatLab simulation program Mimic movement of vehicle Include code to manipulate vehicle

Group Members: Chase Davis, Jimmy Simmons, Eric Kneynsberg, Larry Lybrook

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Control Console Testing Plan

The group will provide the user with:◦ User Manual◦ System Specification Document updated weekly

Each sub-system will be independently documented

Documentation responsibilities will be shared by all team members

The group guarantees to deliver a prototype rendezvous system suitable for use as a demonstration during departmental recruiting activities by December 2007

Documentation

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Validate each sub-system before integration◦ Check for desired behavior, performance, stability

Validate each sub-system after integration◦ Check for proper interactions with other sub-systems,

stability, performance Validate the system

◦ Check for completion of objective

Validation Plan

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Ad-hoc method of validation◦ Small scale◦ No plans for mass production◦ Limited access to specialized testing equipment◦ Limited time to implement and refine a systematic

validation procedure Acceptance will be defined by client’s acceptance

standards and the equipment’s rated tolerances

Validation Plan

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Compasses, $106.65

Short Range IR Sensors, $27.65

Long Range IR Sensors, $27.65

Wireless Modules, $38.00

Wireless Board, $60.00

Microcontrollers$199.91

CMUCam2, $179.00

Batteries (4500 mAh),

$70.00

Batteries (2300mAh),

$28.00

Platform, $80.00

Optical Sensors, $10.80

Misc ICs and Regulators,

$20.00

Unused, $152.34

Estimated Budget

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Compasses,$106.65

Short Range IR Sensors, $27.65

Long Range IR Sensors, $27.65

Wireless Modules, $38.00

Wireless Board, $60.00

Microcontrollers$199.91

Unused, $540.14

Current Budget

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Schedule

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Control system failure Collision with people

or other objects Possible hazardous

materials in system components

Possible hazardous payloads

Safety Problems

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Long range operation uses long range IR sensors◦ Line up yaw and Y axis from long range

Short range operation uses short range IR sensors and color camera◦ Stop movement if IR sensor and camera data don’t

match or are out of expected ranges◦ Variable speed based upon distance from target

Collision Avoidance

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Simulation of 3D rendezvous problem through 2D problem solving

Breakdown problem into sub-systems◦ Platform◦ Wireless communication◦ Image processing◦ Navigation◦ Control console

Safety concerns◦ Collision avoidance

Overall deliverable◦ Working prototype that can rendezvous autonomously

with a target within system specifications

Conclusion

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Questions?

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