Autonomous Ground Support
Equipment – Project WALL-Eagle
Overall AGSE Concept
Overall AGSE Concept
AGSE Payload Hatch
Payload Hatch Function
• Seals payload bay during flight
• Hatch opens and closes
autonomously with a
microservo
• Guides robotic arm into
payload bay
Payload Access Plate and Positioning
• Single access plate revolves on
hinge
• Hinge operates with
microservo
• Will allow remote opening and
closing
• Optical markers to guide
robotic arm
Payload Access Plate and Positioning
• Single access plate revolves on
hinge
• Hinge operates with
microservo
• Will allow remote opening and
closing
• Optical markers to guide
robotic arm
Payload Hatch Animation
AGSE Payload Capture &
Transport
Robot Arm Capabilities
• Needs at least 4 degrees of freedom
• Controlled by central master-controller
• Detect Payload via IR sensors
▫ Backup: Navigate to predetermined location
• Be able to lift 4 oz. payload
• Navigate over payload and rocket hatch
Fabricated vs. Purchased
Fabrication Advantages:
▫ Customizable for any purpose
▫ Cost-effective
▫ Deep subsystem educational
merit
▫ Unique and original
▫ High scientific merit
Purchase Advantages
▫ Commit team-member time
elsewhere
▫ High-performance
▫ Reduce risk of subsystem
failure
▫ Compensate for lack of teammember experience
▫ Customizable parts
▫ High scientific merit
Decision: Purchase Robot Arm
• Chose to purchase commercially available arm.
• High performance, legacy, and affordability
warrant purchase of arm.
• Arm like Lynxmotion AL5B or AL5D possible
choices.
CrustCrawler AX-12A Smart Robotic Arm
• ~22” maximum reach
• 5-6 degrees of freedom
• Most value and capabilities
for the price
• Completely customizable
• Price - $830
CrustCrawler AX-12A Key Features
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1mbs serial communication protocol
 Dual actuator design in the shoulder and wrist axis for maximum lifting
capability (2 to 3 pound (.907kg to 1.36kg)
 Fully ROS,MATLAB,LABVIEW Compatible!
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Rugged, all aluminum construction for maximum kinematic accuracy (1mm - 3mm)
Hard Anodized finish for maximum scratch and corrosion resistance
 Compatible with ANY micro-controller/computer control system /
programming Language (Open Source!)
 The only robotic arms that feature feedback for position, voltage, current and
temperature
•
Smooth, sealed, self lubricating ball bearing turntable
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(3) integrated mounting tabs for easy mounting to a fixed or mobile base
(5) Gripper options to choose from
 Fully adjustable initial base angle
 Full control over position (300 degrees), speed, and torque in 1024 increments
• Automatic shutdown based on voltage or temperature with status indicator LED
 Sensor engineered gripper design accepts, pressure sensors, IR detectors, CCD
cameras and more!
Robot Arm Gripper Requirements
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Able to hold cylindrical payload
Support 4 oz. weight
Reach ground/reach payload bay
Able to rotate at the wrist
Able to sense that payload has been obtained
The Big Grip Kit from the CrustCrawler AX-12A series
robotic arms meet criteria plus more
IR Sensors
• Affixed to front of grabber, scans dark ground
(grass/dirt) for light surface (payload).
• Arm engages payload once detected.
• If payload dropped, search and capture of the
payload may be repeated until mission success
Contingency: Preprogrammed Location
• Use preprogrammed location of payload in case
IR sensors plan doesn’t work out
• Can choose location of payload, so static
coordinates suffice
• Easier, but will cause launch failure if payload
dropped
AGSE Launch Rail and Truss
AGSE Truss
• Constructed out of durable
carbon fiber
• Designed to support the full
weight of the rocket
• Connected to two electric gear
motors
• Rotates from horizontal to 85°
• Returns to horizontal after
rocket launch
AGSE Truss
• Bottom is counterweighted to
ease lifting
• Measurements ensure bottom
does not contact the ground
• Rocket attached to truss via
slotted rails
• Attachment rails double as
launch rails ensuring launch
stability
• Truss will lock in vertical
position once erect
AGSE Truss
• In launch position, blast shield
protects sensitive components
• Igniter insertion system
extends into motor
• Rocket is then ready for
inspection
• Once inspected, rocket is ready
for launch
AGSE Igniter Insertion System
Igniter Insertion System
• Toothed insertion
system
• DC electric motor drives
the tooth extender into
the mast
• Initiated with a program
that is linked to the
AGSE controller
Igniter Insertion System
• Located 6-8 inches
below the base of
the rocket.
• Main motor is
protected by the
blast plate
• Rise through a
whole in the blast
plate to access the
rocket
Igniter Insertion System
• Extension of 21 inches
• Igniter pause at full
extension
• E-match attached to tip
of the insertion system
is in contact with motor
• Inspection and arming
of the rocket
• Countdown ensues,
followed by blast off
Igniter Inserter System
Master Microcontroller and Full
System Operation
Master Microcontroller
• Single microcontroller drives
all AGSE functions
▫ Simplifies design
▫ Minimizes risk
▫ Eliminates communication
between multiple
microcontrollers
• Arduino mega or comparable
device used
Subsystem Connectivity
• All autonomous
systems connected
through
microcontroller
▫ Only launch
controller handled
independently
• Single start, pause,
and reset switches
Nominal AGSE Process
• Start command received
• Robotic arms commanded to
find payload
• Arm deposits payload in rocket
• Payload bay hatch closes
• Launch rail raised
• Igniter inserted
• Sequence pauses
• Launch button depressed
• Rocket launches
AGSE Flow Chart
• System inspected prior to
launch
• In some cases it is possible to
reset and re-run sequence in
an error has occurred
Risks
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Power Failure
Programming Errors
Equipment Assembly Errors
Component Synchronization
Failure
• Sequence exceeds allotted time
(10 minutes)
• System unresponsive
• Damage from environment
(humidity, rain)
Test Plans
• Full system test (normal
conditions)
• Off-design rocket mass
• Off-design payload
configuration
• Partially drained batteries
• Power failure during AGSE
sequence
• Dropped payload