william sandqvist william@kth.se our pic ”kitchen lab” who has said that pic-processors aren’t...
Post on 03-Jan-2016
225 Views
Preview:
TRANSCRIPT
William Sandqvist william@kth.se
Our PIC ”Kitchen Lab”
Who has said that PIC-processors aren’tRocket Science ?
William Sandqvist william@kth.se
REXUSRocket-borne Experiments for University Students
ESRANGE Sweden mar 2010
William Sandqvist william@kth.se
Mission, deploy a web in space
MissionTo deploy a net in zero
gravity
William Sandqvist william@kth.se
What to do with a web in space?• Could be used as an Antenna?
• Could be a lightweight platform for miniature crawling construction robots?
William Sandqvist william@kth.se
How to unfold a web in zero gravity?
?( when Fuglesang isn’t there to help )
William Sandqvist william@kth.se
First: How to fold a web?
From Mattias Gärdsback and Gunnar Tibert
This is the Miura-Ori folding scheme
Some Japanese origami is needed
William Sandqvist william@kth.se
Scater spinning on ice
Initial Unfold
Law of the Conservation of Angular Momentum
Rotation will slow down!
William Sandqvist william@kth.se
The ”spinning scater principle”
The ”spinning scater priciple” can’t unfold the net.
If the initial rotational speed is to low, the final centrifugal forces won’t be strong enough to deploy the net.
If the initial rotational speed is to high, the energy transfered from the hub to the net will cause oscillations – then the net will be tangled.
Won’t Work!
Rotate the hub with weights attached to the corners of the web, then the centrifugal force will unfold the web?
William Sandqvist william@kth.se
Reaction wheel to ”help” the rotationThe stabilizing rotation of the web
centrifugal force
Reaction wheel
hub
William Sandqvist william@kth.se
Controled unfolding
Nice!
William Sandqvist william@kth.se
Simulation of the reaction wheel motor voltage during controled unfolding
Simplified control is possible!
From Mattias Gärdsback and Gunnar Tibert
William Sandqvist william@kth.se
Gyro to sense hub rotation
The gyro
Sensitivity: 5mV/ °/s
1 Hz (360°/s) 1.8 V0.1 Hz 0.2V0.01 Hz 0.02V
William Sandqvist william@kth.se
Reaction wheel controler card
RWmotor
Now ejected signal
Gyro (x),( y), z,temperature
Release the net signal
E [V]Start now signal
PIC Micro PWM
DIR
With simplified control, one simple PIC Micro could do the job!
William Sandqvist william@kth.se
First PICKit 2 and breadboard
William Sandqvist william@kth.se
Zero gravity on earth?
Problem: motor cold not move flywheel!The gravity caused friction in the bearings.
When the flywheel was lifted with a string everything worked! Zero gravity on earth!
William Sandqvist william@kth.se
Board layout, and manufacturing
Our LKPF facility
William Sandqvist william@kth.se
Wait for:Esrange Februari/March 2010
Sorry: We didn’t deliver a working board in time.
(and there were other problems elsewhere)
William Sandqvist william@kth.se
The Orion rocket
No PIC-processor in space (this time)
William Sandqvist william@kth.se
Circuitboard with testprogram
William Sandqvist william@kth.se
Circuitboard and testprogram.
a auto testm motor testg gyro testl led tests signal testwrite command:
A degree project was performed by student Andreas Svensson in order to assure that we in the future, given a second chance, have a board that works,
Demonstration with PICKit2 UART Tool
William Sandqvist william@kth.se
a auto testm motor testg gyro testl led tests signal testwrite command:
top related