June 20, 2018, 08:46:11 pm
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Messages - zacodonnell

Pages: 1 [2] 3 4 ... 33
16
Progress Reports / Re: Team Tamper Resistant
« on: February 11, 2018, 06:07:48 pm »
I think I get it. #1 looks a lot like the toggle point on a four bar linkage. At the toggle point, the force could either cause it to expand or collapse depending on whether the rear-most pin goes up or down. I think time in this state will be very hard on the mechanism so making a successful transition will require going through this state quickly. If you don't, a lot of energy will be spent trying to compress the linkage / stretch the longer bar. You'll have to make sure that there is no load on the system from the opponent near the transition point by tuning the length of the slot in your original image.

It would be cool to see in action, but my guess is that at the speeds you'll want out of the flywheel that transition point is going to be hard to avoid. Is there a way to limit that issue?

-Zac

17
Progress Reports / Re: Team Tamper Resistant
« on: February 10, 2018, 07:48:36 pm »
Apparently I missed this post in July about a flywheel powered flipper linkage. I am only barely able to visualize what you're talking about, and would benefit from a couple of images of a partially engaged state as well as the freewheeling and fully engaged images you provided. It sounds like a neat project indeed. I know I'm a little late to the party, but did you ever happen to build a mockup of it?  Even if you represent the flywheel as just a stack of watercut parts to see if the mechanism functions in a manual model would be very cool.

-Zac

18
Progress Reports / Re: Team Brain Damage
« on: February 10, 2018, 07:39:27 pm »


I did the last bits of maintenance on the bot today. Replaced the rope, cleats, return bungee, and bumpers. I also made spare bumpers (I have lots now). I'm hoping the sensors drammatically reduce the need for me to swap bumpers every match, but they're not that expensive or difficult so I figured I'd have extra. I still need to swap the new wheels in. These are looking pretty rough after my testing. My plan is to organize my stuff and paint stuff tomorrow morning, then pack it all up in the evening.

I'm very satisfied with the self righting even at low flywheel speeds. I think the sensors are the big difference maker there because they ensure it goes to full extension regardless of how long the magnet has to be on. The flips in the video are so-so but the target is backed right up against the test box wall so there isn't really anywhere for it to go. The angle of the flips is definitely more forward than up, but it makes for some good shots into the plastic in front of the judges :)

Pictures:
https://plus.google.com/photos/107279152885550274671/album/6510901572747399649/6521088089889470914

Video:
https://youtu.be/uZRkuOkTNMA

-Zac

19
Progress Reports / Re: Twisted Sick Robotics
« on: February 10, 2018, 07:20:15 pm »
It's looking really mean. Are the frame rails .25" 6061? With the standoffs I'll bet it is really stiff and solid when you tighten it all down. Mine is like a bowl of spaghetti in comparison :)

-Zac

20
Progress Reports / Re: Team Brain Damage
« on: February 08, 2018, 10:22:14 pm »
More fun with cleats tonight. The shorter cleats work fine once I cut the outriggers off. In fact, in one of the tests the robot actually leaps forward after flipping the target. I'm not sure where that reactive force came from unless it was spring tension built up in the frame... Any thoughts? It makes for a cool flip though :)

Video
https://youtu.be/7al5lmLHymM

Pictures:
https://plus.google.com/photos/107279152885550274671/album/6510901572747399649/6520388756132149346

-Zac

21
Progress Reports / Re: Team Brain Damage
« on: February 07, 2018, 10:12:21 pm »
I got the new cleats cut out and mounted tonight. They came out ok, although I didn't have time to test them yet. There are a couple of things that might make them more effective but I want to watch the video before I try anything else. I took some pictures and also uploaded a few of the frame modifications I did before.

https://plus.google.com/photos/107279152885550274671/album/6510901572747399649/6520015569117808946

-Zac

22
Progress Reports / Re: Team Cosmos
« on: February 06, 2018, 09:53:27 pm »
Also this brings back memories of the first ever robot video I saw online.  It took a whole night for me to download a 20 second clip of hazard hitting a shopping cart. Thanks for the flashback.

-Zac

23
Progress Reports / Re: Team Brain Damage
« on: February 06, 2018, 09:45:57 pm »
I think I traced the drive issues to a loose receiver wire on that drive controller. I was able to reproduce it by tapping on the wiring harness / controller while trying to drive. At first I thought it was something internal to the controller, but when I went to swap the controller out I found an untaped rx wire extension in the chain that had the connector mostly pulled out. My extensions have a little plastic clip that is supposed to hold the parts together, but I always tape them anyway. Looks like that's a good plan as this one appears to have separated just from my test flips. I got it put back together and could no longer reproduce the problem on the bench.

I moved on to planning out the updated cleats that will hopefully not bend the frame as much. They're going to be angle brackets that share the load between the front and side rails and extend much less far from the robot. I'm hoping that with good cleats I can actually cut the outriggers way down, which would give me better reach on the opponents as well as providing the weight for the beefier cleats. I'll work on that tomorrow or Thursday. With any luck the snow will force work to cancel :)

-Zac

24
Progress Reports / Re: Twisted Sick Robotics
« on: February 05, 2018, 09:05:51 pm »
What adhesive did you use? And how much diameter did the tread add? They look grippy :)

When my drive setup is working, it's way more power than the wheels are putting down. I long for more traction, but don't have any weight or time to do something like this. Perhaps next time if it works well I can, uh, rip off? your design

-Zac

25
Progress Reports / Re: Team Cosmos
« on: February 05, 2018, 09:03:14 pm »
This is gonna be great! I have brought a shell spinner to Motorama I think every year since 2004. There's some sweet irony in the fact that 2004 was the last year Killabyte competed there, and that I am unable to bring Triggo this year. It's like the essence of the shell spinner is passing back and forth :). I'll definitely be rooting for it to put on a good show.

Can't wait to hang out with everybody

-Zac

26
Progress Reports / Re: Team Brain Damage
« on: February 05, 2018, 08:57:39 pm »
I agree, it is being a bit frustrating. I didn't have any time to work on it last week either. If I can't get it to be pretty reliable before the show I'll swap the old setup back in and try again next time. My biggest fear is thinking it is working and having it flake out on me during a fight.

Hopefully more to come on this tomorrow night.

-Zac

27
Progress Reports / Re: Team Cosmos
« on: January 29, 2018, 10:20:36 pm »
Looking forward to it, since I'm too lame for Facebook :)

-Zac

28
Progress Reports / Re: Team Brain Damage
« on: January 29, 2018, 10:19:26 pm »
More work on the bot tonight. The left side drive system is still giving me fits though. The right side has worked this entire time, so I'm starting to suspect it's specific to either the wiring harness for the left side or the controller. I have a couple of backup controllers to try, so I'm going to swap one of them in and replace all of the signal wiring between the controller and the receiver for good measure. I prepped the backup controllers tonight and the glue is drying now. Here's a testing video with some comentary. Toward the end I started to think it was mechanical instead of straight electrical noise...
https://youtu.be/Xd7sWcAbFAs


The outriggers are bending already, so maybe that weight reduction hole in the front was a dumb idea. I'm going to try to remake the cleats as pieces of angle tucked in the front corners to try to take some of the leverage off of the outriggers. I tried a flip without cleats but that was pretty scary. All I can say is Hooray for Lexan! This is the reason I have a door on my test box :)
https://youtu.be/miDasiB7Heg

-Zac

29
Progress Reports / Re: Team Brain Damage
« on: January 28, 2018, 07:45:05 pm »
I tracked the issues down. It was painful and time consuming, but eventually I was able to get one-wire programming of the controllers to work from my laptop. There was some wrestling with the drivers and settings involved but in the end I'm happy with it. I still need to prep the other two controllers I got as spares since I'm sure the motors could do bad things to the controllers if they get jammed up.

I did some more weight reduction this weekend too. Hollow front axles, shorter drive axles, and remade the side rails with more pockets. I even put a 1" hole in the outriggers now that I know 1.5" thick outriggers were *almost* enough (after balhogs chopped my existing ones in half)

Adding up all the bits of the bot (didn't have time to assemble it) shows 29.996 lbs.  Not too shabby!

-Zac

30
Progress Reports / Re: Team Brain Damage
« on: January 23, 2018, 09:47:22 pm »
A little more fun with programming the drive controllers tonight. Need to actually make a change that I can verify as it seems like the tool reports success even if I don't attach a controller.

-Zac

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