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#451
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Re: BRONY THREAD
Also, my school's email was down for a few days. If you sent me something, and I didn't respond, I'm really sorry. I'll be able to tackle my emails tomorrow, once my school gets itself together.
EDIT: I can't find your email address anywhere. Could you post it so I could get in touch? Also, thank you guys so much. FIRST means so much to me and it's heartwarming to know I won't have to leave the activity for trivial reasons. You guys are really generous, and it's hard to find the words to express my gratitude. Thank you guys so much. Last edited by alxg833 : 04-02-2013 at 21:51. |
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#452
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Re: BRONY THREAD
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My email is: avrisaac555@gmail.com |
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#453
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Re: BRONY THREAD
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#454
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Re: BRONY THREAD
PIDs? Sounds important..... Sounds like I have some reading to do.....
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#455
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Re: BRONY THREAD
PID is a nice controller? to get something to be at something else.
Ie, Flywheel to be at X RPMs, or move an arm so a POT is at X volts. We used it on our shooter last year. Labview(if you use it) has some nice examples on it. It's just a pain to tune. Not sure if we are going to use that this year, or try Bang-bang. Last edited by Nirvash : 05-02-2013 at 13:45. |
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#456
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Re: BRONY THREAD
PID is a controller that uses Proportional, Integral, and Derivative equations to controla linear system. Cruise control in a car is a good example of how PID is used; the car knows how fast it is going, how fast the driver wants to go, and the computer does calculations to determine how much power to send to the wheels.
Wikipedia has some good information about how PID works, some information on manual tuning, and how adjusting each parameter changes how the system reacts. Bang-bang control a quick implementation PID, with the P gain set high and ID set to zero, and with only on and off output instead of the full range of values the motor controllers can accept. Theincreased complexity of PID comes with the increased control over the system. We used both bang-bang and PID a few days ago on our shooter motor; both worked however PID was smoother and allows you to set any speed instead of having to hard code values. |
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#457
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Re: BRONY THREAD
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#458
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Re: BRONY THREAD
I used the manual tuning method in 2011 when I programmed a crab drive system. The way I tuned the PID was I set all 3 values to 0 and then increased the “P” value until it oscillated around the set point. I then started increasing “I” until the oscillation settled down. For the crab drive system just using the “PI” was sufficient; for a flywheel you might need to put a small value in for “D” to smooth out the change in speed caused by firing a Frisbee.
I tuned the system completely by adjusting the values one at a time until I got to a system behave like I wanted it to. After about 2 hours, without using any of the advanced math, I was able to get the PID for both sides of the robot tuned in. The Wikipedia link I posted links to the section that describes how to tune the PID without math. Once you get a sense of how each value effects the system it becomes easier to tune it. I came up with the following scenario after teaching myself how to tune the PID on the crab driver system: A very simplified scenario of how PID works is a car is driving down the highway at 55 MPH and the driver wants to go 70 MPH. The “P” value would be how hard they step on the gas to accelerate; the greater the “P” value the harder they stop on the gas. The “I” value would be how quickly the driver changes the pressure on the accelerator as they approach 70 MPH; a larger value results in getting to 70 MPH quicker but overshooting 70 and having to slow down. Finally the “D” value would be how smoothly the driver corrects for the speed not being 70 MPH; a larger value means the driver is more likely to overshoot 70 MPH initially but the overall speed changes will be smoother and not bounce above and below 70 as much. Hope this could help. |
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#459
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Re: BRONY THREAD
This is useful, but it isn't ponies!
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#460
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Re: BRONY THREAD
Just a head's up, it's better to put large images in spoliers because then we don't have a giant post of images accounting for more than half of the page. Although I agree, we need moar ponies.
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#462
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Re: BRONY THREAD
Ah well you see... Me and aeniug2 made that one day out of boredom over skype. I took some RD vectors I had lying around on my desktop and recolored it, then he made the sick background and text. He did most of the work. Props to his skill he can make some pretty cool things
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#463
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Re: BRONY THREAD
That OC is really cool. I always thought FIRST needed a few good OC's. Judging by the kind of activity it is, I'm surprised we don't have more bronies. On a side note, would it be rude to send emails asking for "assignments"? Just wondering, on account of the fact that my situation is kind of weird.
![]() Also, my avatar's now obsolete, so should I edit it in photoshop or something, or keep it the way it is? |
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#464
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Re: BRONY THREAD
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#465
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Re: BRONY THREAD
No, the image of Twilight Sparkle will still remain a unicorn.
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