Dec 13, 2009
Dec 11, 2009
Design-Expo
Competition Day:
The potentiometer for the fixed-axis motor has been fixed now allowing us to change directions at will as opposed to when it only allowed us to rotate in one direction and if the direction was changed the motor would draw large amounts of current more than the motor could handle and would subsequently short.
The results were dramatic. Our arm was moving faster and was more responsive. It scooped the balls out with relative ease and tossed them into the opponents tank. We were seeded 26th but managed to upset the 7th seed thanks largely to our defensive cart that obstructed the movement of their cart. In the second round, we again performed well but were unlucky as we knocked ping pong balls out of the arena which counted against us in the tie-breaker.
Overall, we were satisfied with the performance of our machine. Improvements we should have made had time been more forgiving:
a) a lighter material for our rotating arm
b) a more suitable way of attaching the spring to our collapsible arm. this would have allowed us to scoop the balls further away.
c) one of the wheels came undone on our defensive cart and hence started to slip even before the competition started which obviously went against us.
The potentiometer for the fixed-axis motor has been fixed now allowing us to change directions at will as opposed to when it only allowed us to rotate in one direction and if the direction was changed the motor would draw large amounts of current more than the motor could handle and would subsequently short.
The results were dramatic. Our arm was moving faster and was more responsive. It scooped the balls out with relative ease and tossed them into the opponents tank. We were seeded 26th but managed to upset the 7th seed thanks largely to our defensive cart that obstructed the movement of their cart. In the second round, we again performed well but were unlucky as we knocked ping pong balls out of the arena which counted against us in the tie-breaker.
Overall, we were satisfied with the performance of our machine. Improvements we should have made had time been more forgiving:
a) a lighter material for our rotating arm
b) a more suitable way of attaching the spring to our collapsible arm. this would have allowed us to scoop the balls further away.
c) one of the wheels came undone on our defensive cart and hence started to slip even before the competition started which obviously went against us.
Dec 8, 2009
Final
The project has finally been assembled. The key shaft was redesigned and now is epoxy-free! We altered the shape of the shaft hole by making it roughly semi-circular and milling the corresponding portion of the shafts.
Dec 6, 2009
Defensive Cart: Success
The defensive cart worked like a charm. We set the gear-ratio to the maximum possible on the double-gearbox 344:1. We figured that more torque would be better than frequency as we simply intend to disrupt others and in order to that we need more grip, more torque!
Nov 29, 2009
Updated Schedule
The updated schedule:
Modify Bucket - 2/12/09
(includes addition of felt to the bucket to prevent scratching of sides)
Modify length of arms - 3/12/09
Decorating cart - (8/9) /12/09
Experimenting - (8/9) /12/09
Competition Day 10/12/09
Modify Bucket - 2/12/09
(includes addition of felt to the bucket to prevent scratching of sides)
Modify length of arms - 3/12/09
Decorating cart - (8/9) /12/09
Experimenting - (8/9) /12/09
Competition Day 10/12/09
Disaster struck! On the day of testing, the one thing we were sure wouldn't fail us was the shaft-arm as it remained solid the entire 3 weeks ever since it had been manufactured! We now have to go back to the drawing board and redesign the shaft arm!
We have drilled additional holes in the arm to allow us to have adjustable arm lengths. The Cart is almost complete. The toughest portion was getting the flexible tubing on the threaded 1/4'' shaft. We secured it with zip-ties to prevent slip. We built a supporting structure to house the controller on top of the motor. The leads will simply be plugged into the controller and it should be ready.
We have drilled additional holes in the arm to allow us to have adjustable arm lengths. The Cart is almost complete. The toughest portion was getting the flexible tubing on the threaded 1/4'' shaft. We secured it with zip-ties to prevent slip. We built a supporting structure to house the controller on top of the motor. The leads will simply be plugged into the controller and it should be ready.
Nov 22, 2009
MCM due
MCM due. Let's see how we fair in that. The arm seemed to be rotating in the hole but the spring hasn't been attached and neither has the auxiliary motor been added so no luck checking it out!
The bucket has been design so that it can cradle the ping-pong balls easily. We tapped holes into the collapsing arms and drilled holes in the bucket's backface to allow us to attach them together.
The bucket has been design so that it can cradle the ping-pong balls easily. We tapped holes into the collapsing arms and drilled holes in the bucket's backface to allow us to attach them together.
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