AS-0.3200 Winter robot final presentation Group: O-P Osmala, Heidi Rintahaka, Jori Rintahaka.
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Transcript of AS-0.3200 Winter robot final presentation Group: O-P Osmala, Heidi Rintahaka, Jori Rintahaka.
AS-0.3200 Winter robot final presentation
Group: O-P Osmala, Heidi Rintahaka, Jori Rintahaka
Assignment
Environment: ice and snow
Propulsion: wind power
Built using Lego
Project plan
Four milestones with smaller tasks 1: Ready to build 1st prototype 2: 1st prototype built 3: 2nd prototype and intermediate presentation 4: Final robot and presentation
Main responsibility areas for group members Heidi: mathematical modelling Jori: software & project management O-P: mechanical design
Milestone 1: Ready to build 1st prototype Due 2.2.2011, reached 4.2.2011 55h estimated, ~60h spent What was done:
Lots of research, sketch mathematical model constructed Propulsion method (sail) + steering method
(turning/tilting skis) selected Parts weighted, size estimated, skis acquired SDK installed, connection to robot established Missing parts ordered
Challenges: Aerodynamic model of a sail is very complex Everything affects everything in the mathematical model
Proto-prototype
Milestone 2: First prototype built Due 22.2.2011, reached 1.3.2011 105h estimated, ~80h spent What was done:
Prototype built (without sail) Steering by tilting the skis instead of turning them Primitive Bluetooth interface Control loops for servos Servo torque model
Challenges: NXT built-in servo control is useless No debugger Jori & Heidi sick all the time Getting COMSOL license
Servo torque model
Torque required by the servo which takes the larger share of the load
Maximum possible torque ~25Ncm with brand new batteries, 20Ncm “safe value”
First prototype
Milestone 3: Second prototype and intermediate demo
Due 23.3.2011, reached 22.3.2011 100h estimated, ~140h spent What was done:
Built turning sail (needs 3-4m/s of wind to move) Shortened legs, strengthened chassis Nonlinear controller for servos Bluetooth remote control Lots of testing
Challenges: Incredibly calm period, no wind at all! Jori & Heidi sick again
Minimum and maximum sail size model We see that the range of a “good” sail area is
very small! (Assumed static friction coefficient here is 0.15)
Friction model It is clear that it’s very difficult to build a sail
that would work well in all weather conditions
Second prototype
Milestone 4: Final presentation Due 11.5.2011, not yet reached 70h estimated, ~100h spent What was done:
Built improved sail Strengthened sail connection Better servo control Wind tunnel sail model
Challenges: Snow melted Everyone sick COMSOL awkward to use
Sail in wind tunnel
The robot now
A trip to the snow dump
Conclusion No one sail can accommodate all weather
conditions Proven mathematically and experimentally Sail should either be very easy to switch, or some
mechanism should adjust it Building the body with Lego's has its ups and
downs Easy to experiment Very difficult to build anything sturdy, needs glue Gear boxes impractical to build
Steering is very difficult The servos need to be very strong Tracks in the snow are difficult to get out of