William Sandqvist william@kth.se Our PIC ”Kitchen Lab” Who has said that PIC-processors aren’t Rocket Science ?
William Sandqvist william@kth.se Our PIC ”Kitchen Lab” Who has said that PIC-processors aren’t Rocket Science ?
William Sandqvist william@kth.se REXUS Rocket-borne Experiments for University Students ESRANGE Sweden mar 2010
William Sandqvist william@kth.se Mission, deploy a web in space Mission
To 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 rotation The 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 V 0.1 Hz 0.2V 0.01 Hz 0.02V
William Sandqvist william@kth.se Reaction wheel controler card RW motor 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 test m motor test g gyro test l led test s signal test write 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,
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