Author Topic: Team Brain Damage  (Read 70478 times)

zacodonnell

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Re: Team Brain Damage
« Reply #375 on: January 27, 2019, 10:44:09 pm »
Not quite as much progress as I wanted today, but not too bad.

After the battery swap I worked on the weapon motor mounting and some electronics prep. I got the weapon motor in and the connectors on it and the controller. I'm happy with all of it. Slow progress, but good progress.



Album updated too:
https://imgur.com/a/5fndlb9

-Zac

rcjunky

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Re: Team Brain Damage
« Reply #376 on: January 28, 2019, 02:14:04 am »
Looking good. I look forward to. Seeing the shell in all its glory.

The cell resistance is greatly effected by temp, but for what you're doing it doesn't matter as long as it's consistent like it is. In this case the current rating the esr meter gives will just be low and the resistance will be high compared to what they can really do. 90% of the time I only care about the cell to cell consistency so I don't get too worked up over temp either.
Andrew Burghgraef
Canadian Carnage Robotics

zacodonnell

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Re: Team Brain Damage
« Reply #377 on: January 30, 2019, 10:14:09 pm »
I got the electronics boxes wrapped up and my batteries came today. I even ran home over lunch to put them inside to prevent the subzero temperatures from damaging them. I'll run them through the ESR meter tomorrow to make sure they're ok but it was only ~15 deg when I grabbed them off the front porch.

After getting the electronics boxes in I did a test fit with everything. It all goes in and the top fits without too much fuss. It's going to suck to wire but that's normal. That's basically the list for tomorrow and probably Friday. 



I also got some pictures of the shell progress today from my machine shop. I'm really happy with how it's looking. They still have to do the final bore and press the bearing in after they clean up a couple of the welds and do some grinding.


those teeth are pretty beefy looking. They are interlocked into the shell wall and the bottom flange. I think they'll be stronger than any that I've had before. This whole shell is AR400 which should be stronger than the annealed 4130 I used before by a big margin too.  I did flame harden the old teeth - I'm not sure how these will hold up in the regular form. I'm getting pretty excited - supposed to pick the shell up Friday morning if I can survive the drive to the shop and back :)


Pictures:
https://imgur.com/a/5fndlb9
-Zac

rcjunky

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Re: Team Brain Damage
« Reply #378 on: January 31, 2019, 03:52:35 am »
I'm really digging that shell design, I think going to AR is the way to go. I wonder if thin enough AR500F could be sourced in the future, and possibly use ar400 for the teeth and lower ring to try avoiding the rest of the shell from getting damaged. Regardless I'm sure this one will take more abuse, but I'm also sure the flat sides will be taking more from horizontal spinners.

I don't believe theres any reason to be concerned with the temp outside with shipping batteries, they don't seem very sensitive to it for short term storage such as shipping times. Definitely lets them reach ambient inside before charging though.

Did ya figure out what you'll be doing for weapon esc's?
Andrew Burghgraef
Canadian Carnage Robotics

zacodonnell

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Re: Team Brain Damage
« Reply #379 on: January 31, 2019, 06:46:06 am »
I talked with the shop about making the teeth out of AR500, but they recommended staying with the same material throughout to strengthen the welds. Because the design is pretty dependent on the strength of the welds I figured some mashing was better than breaking them off at the mounts.

As far as taking more damage than the conical shell, the true test is coming in a couple weeks :)  I'm hopeful that the teeth will take the brunt of it like they have in the past. In fact, the sides of the Triggo shell show very little damage in the horizontal plane, and even fewer above the bottom inch or so:


As long as I keep spinning (which is an obvious requirement anyway) I think the longer teeth should protect more from the horizontal spinners than the sloped sides ever did. I ended up going with a unidirectional Castle 120A HV controller. It fits decently well and is WAAAAY overkill. It came with 8AWG leads on the input side and 10 AWG leads on the output side. My weapon motor probably has 12 AWG or smaller leads coming out of it, so the controller is unlikely to be the limiting factor. I'm pretty sure now that the 80A version would have been overkill too, but lots of headroom on the controller is good in my opinion. Castle lists their 120A rating as determined by sustaining it for the length of a 10,000 MAH battery pack at 14S. I'm only carrying 2600 mah and 12S, and I'm sure the roller wheel and motor would go up in smoke if I tried to put 5700 watts through them until the battery ran out. The batteries would also be on fire but the controller would likely be fine.

I can hardly wait to see it spin... and I hope I can fix whatever bad thing happens in my initial tests in time :)

-Zac

zacodonnell

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Re: Team Brain Damage
« Reply #380 on: January 31, 2019, 10:35:22 pm »
Today I tested all the new batteries with the ESR meter (51 degrees in the shop today... -7 outside). They all checked out so I replaced all of the connectors too. I'm happy with how they stand:


-Zac

zacodonnell

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Re: Team Brain Damage
« Reply #381 on: February 08, 2019, 10:29:31 pm »
I've been MIA for a week, sorry about that.  We had a deadline at work on Thursday and that ate up most of my free time and spare brainpower.  I did chip away at the wiring an hour or so each evening this week, and then after we hit our deadline I took yesterday afternoon and today off work to really wrap it up. When you're trying to shove 10 gallons of crap in a 5 gallon bucket it takes a ton of time, and this build is no exception. With the three power switches, five motors, five controllers, and six battery packs there are a lot of wires in this thing. Clearance on the bottom plate is getting pretty tight. I think it's ok, but it makes me a little nervous I'll pinch something when putting it on and off. Once I get it all wrapped up and ziptied down I'll see how it looks, and I may strategically pocket out some of the base to gvie more space.

Here's a picture I took about an hour before wrapping up tonight:


I verified that all the right voltages and polarities exist at all the controllers. Having connectors at every controller makes it easier to validate, debug during the competition, and replace things in a hurry, but it does take up a lot of space.  I know some of that is the powerpole connectors I use for everything, but the XT60's take up a lot of space too. In the end I'm pretty happy with how things landed. I ended up color coding the three sets of connectors. I think that will help me get it all stuffed in there the same way each time. Green is the lower 4S2P pack which controls the drive and contributes to the weapon. Blue is the middle 4S2P pack which is just in series with the first one, and the two separate yellow connectors are for two separate 4S packs that complete the series circuit to run the weapon controller at 12S.  I forgot to take a picture of the packs in the machine - they fill up all the orange space in the picture. All of it.

Tonight I stopped after validating all the connections because I noticed a "hot electronics" smell just during testing and without actually connecting any of the controllers. It made me nervous so I turned the machine off and grabbed my infrared thermometer. I started hunting around with that and my ultra-sensitive nose-o-meter and found the culprit. It turns out running an LED at 40V means you are dissipating an awful lot of heat through a tiny resistor. Once I tracked it down I checked the temp with the LED on. It climbed about 1 deg F per second. That's not gonna work.

I think I'll do the spin test without the LED for now. I have some 500 ohm 3W resistors that might do the trick but for now finding out if it spins is more important. 50V @ 500 ohm is 5W dissipation, but there's another built-in resistor (that I didn't measure yet) and it only has to do it for 10 minutes or so. We shall see.

-Zac

rcjunky

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Re: Team Brain Damage
« Reply #382 on: February 09, 2019, 12:07:57 am »
and here I am thinking running 5 motors, 5 esc's, 2 switches and 3 batteries was bad :P looks like you're in good shape with a week to go.
Andrew Burghgraef
Canadian Carnage Robotics

BranYoung

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Re: Team Brain Damage
« Reply #383 on: February 09, 2019, 01:05:40 am »
Compared to how for along you are, my 30 is put to shame! I'm looking forward to seeing how this mid-plane construction works out. I thought of this way more elaborate requiring lots of parts working together so I'm sure seeing this in action will give me some new ideas.

zacodonnell

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Re: Team Brain Damage
« Reply #384 on: February 09, 2019, 09:22:17 am »
"looks like you're in good shape with a week to go" - only if everything goes 100% as planned... and of course it won't.

First instance of things not going as planned - looks like there's some issue with tying two drive controllers to the same RX channel. If I disconnect one from the y-cable the other one initializes with no issues. If I disconnect that one and connect the other then the other works fine. If they are both plugged in then I just get the "no signal" beep

My guess is that the controllers are trying to communicate over the signal lead and having two connected is borking things. They are Afro 30A ESCs with SimonK flashed on them and the bootloader enabled. My guess is the bootloader initialization is conflicting.

If I have to get them on separate rx signal channels I can either put a second RX in the bot or try to come up with some mixing settings that will slave a second pair of channels to the drive channels. Anybody have better suggestions?

-Zac

zacodonnell

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Re: Team Brain Damage
« Reply #385 on: February 09, 2019, 09:53:05 am »
I checked the motor direction with each controller plugged in separately and noticed that it was running like it was the other side of the robot. I decided to swap the Y cable to the other channel and leave both motor controllers connected. It worked - initialized fine. It's possible it was some kind of a calibration issue but very odd that the controllers worked fine independently and not when attached together.

For now I'll move on. Just did a check to make sure the weapon motor was working correctly too and all is well. I'm going to button up the wiring and then it will be time to do some actual testing.

-Zac

rcjunky

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Re: Team Brain Damage
« Reply #386 on: February 09, 2019, 12:07:12 pm »
I totally forgot about y harnesses for drive, going to need to get some this weekend, thanks for the reminder :)
Andrew Burghgraef
Canadian Carnage Robotics

zacodonnell

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Re: Team Brain Damage
« Reply #387 on: February 09, 2019, 01:15:10 pm »
I only remembered last week and put in a separate order for them. At least *you* have access to a local hobby shop :)

First full power up bench tests were successful. The drive system is all set up to go the right direction now too. I did a wheels up test to verify direction and then a twenty second or so drive test in the box. It's wickedly fast with only half the robot there. Interested to see how it does with the full weight

The weapon motor, belt, bearings, and roller assembly all seem to be ok. I got a slight temperature rise running it full out for 30 seconds, but nothing to be too worried about. Loaded speed will be lower and even at that rate for three minutes it shouldn't get hot enough to matter. Worst case I may need to add a little lube between the pulley and the bearings but I'd like to avoid that in case it finds its way to the roller.

Stopped for lunch real quick then I'll do the first spin test. Fingers crossed.
-Zac

zacodonnell

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Re: Team Brain Damage
« Reply #388 on: February 09, 2019, 10:05:14 pm »
It works. It's terrifying. I think it's louder than some helicopters.

I have more pictures and stuff, but for now, just this:
https://www.youtube.com/watch?v=LM4hUQokDNI&feature=youtu.be

-Zac

Team haciM

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Re: Team Brain Damage
« Reply #389 on: February 10, 2019, 11:18:47 am »
That is flat out nasty!