Quote:
Originally Posted by asid61
I'll be rifling through the CAD later, but for now:
What changes were made between the wooden prototype and the real bot? Specifically, did anything perform significantly better or worse on one version? Was the wooden prototype better in any areas?
Will you be bringing the prototype bot to any offseason events?
How were you able to construct the prototype so quickly!?
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There weren’t any significant changes we made between the prototype and the real robot. The prototype was designed and constructed with the purpose to ensure the mechanisms all worked consistently and cohesively together. That meant that most of our mounting/pivot points which were set on our prototype directly translated over to our real robot. Some big differences were we did not power the drive and the intake arm on the prototype as it was not worth the time, effort and resources to test. These aspects did not necessarily require an accuracy test and we have had enough experience to know we could power them in the final design. Some minor changes included the intake arm being one straight extrusion on the real robot versus the multiple extrusions used on the prototype. We realized we could use the lexan “fangs” above the front of the intake on the real robot instead of using multiple extrusions to achieve the same purpose (to pass through the portcullis while clearing the shooter head as well be able to do the drawbridge), leading to less weight and complexity. Also, the shooter was repeatedly revised on the wooden prototype to confirm our calculations and various tweaks were made to give us the 97% accuracy. That was the prototype we worked on extensively as that was where majority of our points would come. In the first revision, we messed around with the different wheel configurations/ number of wheels to ensure enough exit velocity was being achieved on the ball along with the correct exit angle of the shot. The second revision was a more refined version of the first as at that point we had locked in the combination of stacking 3 urethane wheels 4" in diameter with a 2" pinch as the ideal shooter configuration. We further tested using this configuration and determined our set shooter speeds. Finally, our third and final revision was simply our second revision with a better choice of materials for robustness and durability. We used denser material on the shooter head and beefed up the gearbox by making minor changes like using round bearings vs. hex bearings. This final shooter on the wooden robot is what ended up on the real robot. As for the conveyor, no significant changes were made other than reshuffling of the number of belts required and using banebots on the axles running the belts. Overall, our prototype was extensively used to translate the exact variables from the wooden prototype to our final robot. This meant we strictly used the parameters we discovered from our prototype to the real robot.
The real robot performed better in all the aspects, but not significantly as we repeatedly revised the prototype to the point it could be used as a functioning robot. Our goal was whatever ends up on the real robot HAD to be tested on the prototype.
Our final robot was as good if not better in all areas than our wooden prototype due to the reasons listed above. One feature we decided not to keep for the real robot that was in our prototype, was a pusher bar to expel the ball from the shooter bowl into the conveyor. We decided not to keep this feature due to its lack of usefulness vs. requirement of weight.
Unfortunately, we have disassembled our prototype as we used some of the parts on the real robot, so we will not be bringing it to offseason events.
Take a look at our prototyping process which Jash has outlined above. Following this process religiously is what led us to construct the prototype so quickly.