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System Overview Climber Specs
► The scoring equation for last year’s competition was
mpayload * Vavg/ mstructural
The climber had to be able to ascend a 50m ribbon at an
average speed of 1m/s .
Maximum beamed power of 100KVA.
No previously stored energy.
Maximum energy storage of 25% at any time.
10kg < mstructural < 25 kg
Safety regulations must be met
Power Transmission belt ribbon Early Goals
► Based on the competition rules, the team
delineated some goals concerning the climber,
that were believed to maximize performance on
competition day based on the scoring equation
It should travel at an average speed of 1m/s.
It should weigh about 25kg without payload
It should be able to carry 25kg of payload while
maintaining its average speed. First Recursion
First Lessons from First Recursion
► 1st recursion was a crash course in climber design
in which the team mostly experimented
► Construction and machining mandated that several
aspects of the initial design be modified.
► After testing the first recursion, the team
discovered that the roller configuration was flawed
for it could not generate enough torque.
► The team also discovered that the climber was too
heavy and flimsy. CURRENT DESIGN
► The team applied the lessons from the first recursion to
create a better climber.
The team decided to switch to a two motor configuration
with 50:1 gear ratio which provides substantially greater
torque and weighs as much as the earlier recursion.
Polycarbonate is the primary material instead of
Changed overall design layout to increase stiffness.
Included additional design for a more complete climber
setup that included mount points for failsafe brakes, guide
rollers, belay hooks, payload and electronics. Current Design
► Motor-roller module
► Payload module
► Electronics module
► Power module
► All modules except electronics module have
been modified Motor-Roller Module
► Powered by 2 DeWalt power drill motors.
► Structure made of polycarbonate (including
the roller) which provides greater strength
compared to aluminum.
► Motors are geared to generate necessary
torque. Payload and Power Modules
► Solar panels have been replaced by
rectanna array so the payload bucket’s
status is currently unknown.
► Rectanna array will be attached to bottom
of climber via kevlar or wood attachment. Current Design
Current Current Design
Current Power System
► Climber powered by beam source
► Beam source must direct most of its energy
► Turn on/off at a command
► Only a quarter of the total energy can be
stored Microwave System
► Microwave Efficient
Need magnetron, rectennas
► 800 W Magnetron 5.81 GHz
Diode Vacuum Tube-Oscillates to create
microwave Microwave System
Microwave Microwave System
► Directs the extracted RF energy to the
Out Microwave System
► Dish/Reflector 14 foot satellite dish
► Rectennas Rectifiers and Antennas
Receives microwaves energy and converts
oscillating current to DC Control & Logic
► Controlled by Bitsy Single Board Computer
► Speed Regulation Power Transmission
Design a better, more efficient transmission
Fixed Input - 750W, 5.801GHz signal via waveguide or
Fixed Output - circularly polarized microwaves at same
Current design uses waveguides to transmit signal up to
a hemispherical reflector and back to a parabolic dish,
before traveling in a beam up to the rectenna array.
Goal - to transmit 400W of power to the rectenna array
Goal Rectenna Design
Design - based on a Texas A&M
design which transmitted power on small
► Patch Antennas and rectifying circuitry
► Primary Goals - cheaper and more efficient
► Secondary Goals - Lighter and stronger (self
► Current Control System Design
► Current control system is an analog control system
supported by an onboard computer
► Requires finding many optimal parameters within
► Many of the issues involved are pretty complicated
and require us to find a delicate balance
Varying-voltage power supply
15kF of capacitors that are restricted to 2.5V
Motors that can act with or against our power circuitry
depending on operating levels Gear Ratios
► Current design - Two DeWalt drill motors
Two DeWalt drill .667 N/m of torque @ 21000 rpm
► Gear Ratio - 46.7:1
46.7:1 1.4 N/m torque @ at rollers
1.4 “Hi Speed” configuration - 10.5:1
► Goals - optimize combination of torque and
speed supplied the rollers.
► Second Weight Minimization
► Allowed weight - 10 to 25kg
► Current Design
Polycarbonate is used instead of aluminum or
steel to cut mass
Hollowed out gears
Weight saving roller design
► Goal – Maximize payload to weight ratio
without sacrificing performance. ...
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This note was uploaded on 11/08/2011 for the course AERO 16.810 taught by Professor Olivierdeweck during the Winter '07 term at MIT.
- Winter '07