WinBot II AS Automaatio- ja systeemitekniikan projektityöt

WinBot II Wind powered robot for winter conditions Attempt to improve WinBot I design Project split in to 4 main milestones: – Initial planning and component ordering – Defining robot dimensions – Creating initial structure – Testing and adjusting created structure

Initial planning Target was to work on the flaws of WinBot I: – Lego structure not very sturdy – Robot fell over with stronger wind Desided to make structure out of carbon fiber with longer skis to try fix the problems in WinBot I Considered some form of sail size control

Component ordering For controlling we ordered RC servos and a radio controller for easy control of the robot without the need for a heavy control unit onboard – PWM control allows easy automation in future – Modularity and easy to expand Carbon fiber tubes and sheets were ordered for the chassis, however the delivered sheets were too low quality to use and we decided to get glass fiber sheets of higher quality instead

Defining the robot dimensions WinBot II was designed to be slightly wider than WinBot I for increased stability Longer skis were selected to lower the chance for the robot falling over The sail was decided to be made of some plastic or fabric with increased size to accomodate the slightly larger robot structure

Creating the initial structure Initial chassis was built from glass fiber Controlling servos were directly connected to their target parts using link rods Sail area control was built with a hinge on the mast allowing vertical tilting Sail was built out of a plastic sheet attached to two vertical carbon fiber beams that were connected to the mast via the hinge

Testing and improvement Early tests showed that our sail was too weak, – We had to remake the sail with a sturdy frame Turning with such long skis by only tilting them was undoubtably going to be an issue – An extra servo was added to allow changing of angle of skis Sail turning and tilting servos weren’t powerful enough when connected directly – Connections were made with strings and reels instead. Servos were modified to allow continuous rotation and position feedback sensors where placed elsewhere. Later tests showed that our sail was possibly too large, high winds would throw the robot around in worst case – Sail size was reduced and triangle shape used instead of rectangle

Testing and improvement Vertical tilting of the sail was scrapped as the designed tilting mechanism wasn’t good enough for efficient use – Current model doesn’t have a function to adjust sail size, but it can be easily added for instance by lowering upper horizontal beam with ropes. Weather didn’t permit testing on snow. Test on a parking lot with wheels showed that the robot moved forward and sail size was adequate.

The Result WinBot II motions Winbot II roller test

Pictures

What we achieved / failed Achieved: – Sturdier structure for the robot – Skis’ steering mechanism imporved – Better remote controls and more flexibility for future improvements Failed: – Sail size control – Testing in target environment