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#1
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Minibot climb rate
We have not received our FTC parts yet, obviously because the orders went in today
. I have a couple quick questions and then a result of quick calculations based on assumptions.What are the weights of the following items?: NXT controller, Tetrix motor, 12v battery pack, HiTechnic motor controller. I did some very ballpark calculations based on ideal situations. If we can build a robot weighing less than 5 Lbs, it should be able to climb the pole in less than 7 seconds. Does that sound right? |
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#2
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Re: Minibot climb rate
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What are you basing your calculations on? Overall output of the motors (ie: power)? -Brando |
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#3
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Re: Minibot climb rate
Yep! I chose to run the calculations close the motor's max efficiency. I also chose to use the largest wheel I could find that appeared to be legal.
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#4
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Re: Minibot climb rate
This calculation is actually very easy using the work-energy thorem.
Power = Work / Time Work = weight * height Therefore: Time = (weight * height) / Power Example: Motor power: 8.43 W (Tetrix motor) Efficiency: 0.85 Weight: 5 lb * 4.4545 N/lb = 22.27 N Height to climb: 2.1 m assume gearing for peak power. then: Time = (22.27 N * 2.1 m) / (8.43 W * 0.85) Time = 6.53 sec This is the FASTEST time. If you make the wheel big enough that the torque on the motor causes the motor to move away from the peak power point, the minibot will climb SLOWER, not faster. In other words, bigger wheels aren't always better. |
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#5
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Re: Minibot climb rate
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![]() Just so others can see where I got my numbers, I ran it through the JVN Calculator. |
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#6
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Re: Minibot climb rate
Seems like everyone is forgetting the possible use of surgical tubing to shoot that bot up the pole much much faster.
Also you can use 2 TETRIX motors. Last edited by BornaE : 10-01-2011 at 15:51. |
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#7
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Re: Minibot climb rate
Who says we are forgetting?
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#8
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Re: Minibot climb rate
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-Brando |
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#9
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Re: Minibot climb rate
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Think about dragsters. Getting off the line is just as important as how fast you go down the track. It's all about "elapsed time". |
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#10
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Re: Minibot climb rate
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The minibot challenge will be more difficult than people think this year, mostly due to the timing allowed for it. |
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#11
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Re: Minibot climb rate
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in this thread I'm gonna need a clarification from the Q&A before I'd feel comfortable committing to getting an extra 10 seconds. On the other hand, I want our minibot to be the first one to the top every single time, thus I'm not planning on our minibot needing an extra 10 seconds. -Brando Last edited by Brandon Holley : 10-01-2011 at 16:33. |
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#12
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Re: Minibot climb rate
I think this shines the light on deployment mechanisms just as much as it shines the light on the climbing minibot. Teams won't know if they're lined up properly until the 10 second mark, which means that a missed deployment is as disasterous as a slow robot.
Good catch with the <G68> rule, though I don't think it effects who wins the race. It would simply dictate whether or not last place always got the 10 points, even after the buzzer. |
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#13
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Re: Minibot climb rate
During brainstorming, my team used the minibots in the kickoff video as a reasonable estimate, which appeared to climb the pole in 4-5sec.
--Ryan |
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#14
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Re: Minibot climb rate
So the calculation above is based off one motor?
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#15
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Re: Minibot climb rate
Question: What is the estimated ideal weight for the mini bot?
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