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Author Topic: Team Ambient Chaos  (Read 8311 times)

AmbientChaos

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Team Ambient Chaos
« on: September 23, 2015, 11:59:58 am »
Since the first bot I was designing is no longer going to be made and I'm now building a different bot than the one I started the other topic for, I figured that I would start a new topic to chronicle the build progress of what is actually going to be my first bot and any future bots that I wind up making. 

My first bot (Lapsed Pacifist) is going to be a beetleweight "lifting wedge" design inspired by the heavyweight Polar Vortex.  The lifting is going to be powered by two servos with long arms that should be able to lift the nose of the bot about 6" off the ground.  Here is what I have for the design so far; the older design only had a small flat wedge on the front because anything else would have put it overweight, but I went back to the drawing board and reduced the length of the bot by 1" to give me enough weight to play with to make a wider curved wedge:



Once I get all of the holes placed for connecting everything together with nutstrip I am going to 3D print the chassis parts and load all of the electronics into it to take it for a spin, and after making any final tweaks to the design I'm going to get the metal plates cut by waterjet and I'll cut the plastic parts and make the wedge myself.  I can list the parts that I'm using if anyone is interested.

Unfortunately at this rate I'm not sure that I'll have it done in time for the NERC Franklin Institute event next month, but hopefully you'll get to see it in action at events in the Pennsylvania area in the near future.
« Last Edit: October 13, 2015, 07:54:45 am by AmbientChaos »

AmbientChaos

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Re: Team Ambient Chaos
« Reply #1 on: September 30, 2015, 05:32:30 pm »
I'm still waiting for the last few components to arrive so I can hook everything up and drive it, but I have the prototype chassis all finished. 



I love that it just looks like a basic wedge if you don't know that it has a couple of lifting arms tucked inside of it.  Now comes the fun part of seeing if I can actually fabricate that wedge myself.
« Last Edit: October 13, 2015, 07:50:39 am by AmbientChaos »

Coboxite

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Re: Team Ambient Chaos
« Reply #2 on: September 30, 2015, 06:35:24 pm »
Looking good. You should paint it green for the final version.

Badnik96

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Re: Team Ambient Chaos
« Reply #3 on: September 30, 2015, 06:56:26 pm »
The green looks nice. Good luck with the fabrication.
TEAM IGNITION
FireArrow (Antweight) 23-11
Nocturne (Beetleweight) 5-10 (Retired)
KnightShade (Beetleweight) 0-0
Landshark (Mantis) 1-2

Pennbots 2014 and Bot Blast 2014 antweight champion. Bot Blast 2013 Best Driver and antweight third place.

AmbientChaos

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Re: Team Ambient Chaos
« Reply #4 on: October 01, 2015, 07:46:32 am »
After a bit of brainstorming last night I think that I finally settled on a name for this bot, so say hello to Lapsed Pacifist.

AmbientChaos

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Re: Team Ambient Chaos
« Reply #5 on: October 05, 2015, 12:27:00 pm »
The last of the internal parts for Lapsed Pacifist finally arrived, so I took the opportunity to cram everything into the prototype chassis to see how it all fits.



I'm a bit glad that I've held off on ordering the water-cut parts so far, I'm going to be adding a little more wiggle room in the inner support plates for the servos, it is currently a tight fit to get them in there. It is definitely going to be a bit of a squeeze getting everything wired together, but between the fact that I was already able to close it all up fairly easily and the fact that I think I will end up switching everything to 18AWG wire now that I'm not running with four drive motors, I think that I can make it all work without too much trouble.  Hopefully I'll be able to report back in a few days with a video of Lapsed Pacifist in action once I get it all wired up.

I'm also hopeful that I won't have to do too much to stay under the weight limit.  The aluminum bar that I'm going to make the wedge out of should be almost 9 oz. heavier than what I currently have planned for the finished wedge, so I'm hoping that I won't have to cut too much off of it for the sake of weight.  I'm going to worry about crossing that bridge once I get the rest of the chassis finished and I know exactly how much weight I have to spare for the wedge.



« Last Edit: October 13, 2015, 07:50:09 am by AmbientChaos »

AmbientChaos

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Re: Team Ambient Chaos
« Reply #6 on: October 06, 2015, 05:27:54 pm »
Good news:
I got everything wired up and put together so I can take Lapsed Pacifist for a spin: https://www.youtube.com/watch?v=KwyduvTnb_E
A bunch of the wires in the wiring harness are probably much longer than they need to be, but it closes up with only a little effort so I don't see a reason to spend any more time on it at the moment.
I have now learned that I will most definitely need to put Loctite on the screws holding the servo arms on, even the small amount of driving in the video was enough to loosen them noticeably.
I know at least a few places that I am going to make some very minor changes to the designs so that everything fits like I want it to, but I think that after that I will finally be ready to order the water cut metal pieces.

Bad news:
The stuttering motor problem that I mentioned in my old build thread is still here.

Questions:
While I still think that one of my Wasp ESCs is defective due to the way I can watch it lose power, it now seems that the issue with the motors stuttering unexpectedly is not due to the ESCs since it is now happening on my brand new tinyESCs as well.  What else could be causing this issue?  My first thoughts are the receiver (I have a spare that should be arriving any day now), and the triple-capacitor configuration of cheap capacitors that I have on the motors for noise suppression:

I'm out of ideas for what could be causing this or what I can do to fix it, so I would really love some suggestions on what to do here.

I already have two bars of 7075-T6 aluminum waiting to be made into the front wedge and a spare, and now I'm getting ready to order the parts for the top, bottom, and back plates that make up the bot.  Would I be okay with going for 6061 aluminum for these pieces since (hopefully) the wedge (and maybe the tires) will be taking the worst hits, or would it definitely be worthwhile to spring for getting them made in 7075 aluminum as well?
« Last Edit: October 13, 2015, 08:30:21 am by AmbientChaos »

AmbientChaos

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Re: Team Ambient Chaos
« Reply #7 on: October 07, 2015, 10:41:15 am »
Well, I think that the receiver just became a lot less likely as the culprit for my motor stuttering issues (I was hoping that this would just be as simple as switching out a problem part).  My spare receiver arrived, and while it is the same model as the current one (OrangeRX R615X) I take the fact that switching them out did not solve the issue to mean that it isn't the cause. 

What could be causing this?  From when I first got my circuits up and running and first noticed this issue I have by now changed out the receiver, ESCs, wires, and batteries (also same model).  By process of elimination does that leave my transmitter or motors/capacitors as the culprit?  I can watch the ESCs switching directions when they should be going straight.  Is motor noise causing ESCs to malfunction like that a thing that happens?  Would the better capacitors that came with the tinyESCs or a one capacitor configuration on the motor fix this where my cheap capacitors or three capacitor configuration on the motor did not?  Or is it possible that my Spekrum transmitter has been the culprit this whole time?  I know that the TX/RX are supposed to be 2.4 GHz spread spectrum, but would it be possible for my Wi-Fi to be creating interference that causes this?
« Last Edit: October 07, 2015, 10:56:48 am by AmbientChaos »

MikeNCR

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Re: Team Ambient Chaos
« Reply #8 on: October 07, 2015, 11:16:22 am »
Might be worth removing all but the cap between the positive and negative leads to see if that's influencing things.

TeamTiki

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Re: Team Ambient Chaos
« Reply #9 on: October 07, 2015, 03:27:16 pm »
Try running the RX on a 4.8v battery,  not the BEC from the Esc.

AmbientChaos

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Re: Team Ambient Chaos
« Reply #10 on: October 09, 2015, 09:22:00 am »
Okay, so I've been in touch with FingerTech to see if they could give me any suggestions, and they have been incredibly helpful.  They said that they have never had any other motor that won't run on the tinyESCs, but the KitBots 1000RPM motors are so noisy (and popular) that they send out their ESCs with the 0.01µF capacitors only because of this specific motor.  Looking at RobotMarketplace, the KitBots motors are the only ones I've noticed that they specifically recommend using a (1µF) capacitor to combat motor noise, so I'm thinking this is likely the root of my issue. 

I've also done a little more digging into using capacitors for motor noise suppression in general, and what I gather is that my 0.1µF capacitors might give "more" noise suppression but the 0.01µF capacitors might be better at suppressing higher frequency noise. 

So it looks like my next two steps down the troubleshooting rabbit-hole are to try the 0.01µF capacitors (by themselves and combined with my existing capacitors, I'll try a different configuration with each of my three remaining motors to see if I can find a configuration that works) and to try reducing from a 4S LiPo battery down to a 3S.  I'm really hoping that the capacitors can solve this issue, I think that the extra pep from using the 4S batteries would be really useful in a competition.

AmbientChaos

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Re: Team Ambient Chaos
« Reply #11 on: October 09, 2015, 05:07:49 pm »
Crud.  None of the capacitor configurations that I tried stopped the ESCs from stuttering.  Now I'll have to order a 3S battery to try out, and if that doesn't work I guess that I'll have to change to another type of motor and mounting plates. 

MikeNCR

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Re: Team Ambient Chaos
« Reply #12 on: October 09, 2015, 06:49:52 pm »
Crud.  None of the capacitor configurations that I tried stopped the ESCs from stuttering.  Now I'll have to order a 3S battery to try out, and if that doesn't work I guess that I'll have to change to another type of motor and mounting plates.

Before ordering a new lipo, it may be worth the effort to do a quick test with a 9v battery plugged in and see if the drop in voltage changes behavior. If that doesn't work and you're willing, feel free to send me the bot and I'll see if I can figure out what's wrong. These sort of issues in particular are really tough to troubleshoot remotely.

BranYoung

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Re: Team Ambient Chaos
« Reply #13 on: October 16, 2015, 09:44:55 am »
For this, I bought some of the Banebots 370 sized motors and put them onto the gearbox. Noise and trouble are drastically reduced with a bit of a speed boost as well.

AmbientChaos

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Re: Team Ambient Chaos
« Reply #14 on: October 16, 2015, 11:15:36 am »
It looks like Banebots have discontinued that motor now, but I have some new motors from Pololu that should be arriving today, and I got a 3S LiPo in the mail yesterday.  Hopefully one or both of those new parts will be able to solve the problem.