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Optimal Precision and Consistency
Posted: March 8th, 2016, 8:47 pm
by Bazinga+
Just wondering what you guys think is the best possible (and plausible) accuracy for Air Trajectory. I know that previously, even at nationals, the trajectories didn't have pin point accuracies, and actually had quite a bit variation between shots so top placements had some luck involved. I ask this because I made my trajectory(theoretically) perfect in making as little randomness involved as possible (this includes getting rid of inconsistency from random air flow and from friction, as well as others) and was still not able to get an accuracy that could be considered 'perfect'.
Also, I'm not sure how much this actually affects the accuracy of shots, but it seems that air pressure/temperature could play a significant role when you calibrate in one place and compete in another.
I just thought it was interesting that other events based on accuracy, such as electric vehicle, mousetrap vehicle (any car events), or bungee drop can all be calibrated to have more or less perfect accuracy (to the point that they are more accurate than can be measured), but in this event accuracies like that will never be achieved, not to mention at the more competitive level you only really get one shot at each target.
Re: Optimal Precision and Consistency
Posted: March 9th, 2016, 10:31 am
by watermydoing14
Bazinga+ wrote:Just wondering what you guys think is the best possible (and plausible) accuracy for Air Trajectory. I know that previously, even at nationals, the trajectories didn't have pin point accuracies, and actually had quite a bit variation between shots so top placements had some luck involved. I ask this because I made my trajectory(theoretically) perfect in making as little randomness involved as possible (this includes getting rid of inconsistency from random air flow and from friction, as well as others) and was still not able to get an accuracy that could be considered 'perfect'.
Also, I'm not sure how much this actually affects the accuracy of shots, but it seems that air pressure/temperature could play a significant role when you calibrate in one place and compete in another.
I just thought it was interesting that other events based on accuracy, such as electric vehicle, mousetrap vehicle (any car events), or bungee drop can all be calibrated to have more or less perfect accuracy (to the point that they are more accurate than can be measured), but in this event accuracies like that will never be achieved, not to mention at the more competitive level you only really get one shot at each target.
Probably the best way to get as accurate/precise as possible is learning how to account for the room conditions. Maybe testing your machine at different temperatures and making a graph for the distance it shoots at different angles would be effective, but somewhat hard to do. I guess, each time you test your machine, record the temperature and try to test your machine in different rooms as well, to see how different conditions affect it. In combination with changing the actual design of the machine to account for different conditions, learning how to aim the machine in different conditions could likely get you a more precise/accurate shot
Re: Optimal Precision and Consistency
Posted: March 10th, 2016, 8:54 pm
by SPP SciO
I've also been curious as to what the "limiting factor" is on the most high-end devices. Are teams using custom-milled launch tubes, or precisely measuring air volume and pressure? A wild guess would be 10cm consistency is plausible with Home Depot materials; maybe 1cm with some lab grade apparatus? Who knows? That's the beauty of the competition!
I think Air Trajectory is my favorite event to coach, because the core problem - hitting a small target with a small object - is so timeless and profoundly difficult. But, from the first spear hunters to the engineers who put a spacecraft on a comet, it gets done and is met with much celebration!
Re: Optimal Precision and Consistency
Posted: March 11th, 2016, 7:57 am
by Chris_L
I think +/- 2 cm precision with parts from home depot is more than doable. As long as you use the right materials and test enough that should be pretty easy.
Re: Optimal Precision and Consistency
Posted: March 11th, 2016, 6:46 pm
by DoctaDave
Chris_L wrote:I think +/- 2 cm precision with parts from home depot is more than doable. As long as you use the right materials and test enough that should be pretty easy.
+/- 2cm would be the dream. Last year's winning score at nationals was off by 14cm on one shot IIRC.
I think +/-2 cm is easily doable for short distances like 2-5m but after that the ball has a great chance to deviate from its path. I've found that at 8m even the consistency of the spin of the ball is extremely important; just a few RPS can change the distance of the shot by 5-10cm, which is something that is very difficult to control.
Re: Optimal Precision and Consistency
Posted: March 27th, 2016, 12:06 pm
by DaPlug
DoctaDave wrote:Chris_L wrote:I think +/- 2 cm precision with parts from home depot is more than doable. As long as you use the right materials and test enough that should be pretty easy.
+/- 2cm would be the dream. Last year's winning score at nationals was off by 14cm on one shot IIRC.
I think +/-2 cm is easily doable for short distances like 2-5m but after that the ball has a great chance to deviate from its path. I've found that at 8m even the consistency of the spin of the ball is extremely important; just a few RPS can change the distance of the shot by 5-10cm, which is something that is very difficult to control.
Has anyone been able to reach a +/- 2 cm precision?