November 22, 2017, 08:03:59 am
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Messages - zacodonnell

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1
Progress Reports / Re: Team Brain Damage
« on: October 30, 2017, 06:13:52 am »
I only had Magneato at Franklin. It went about as well as I expected. At the last minute I had to pull out the microcontroller and run everything manually right off of the transmitter. This meant that after flipping the weapon motor didn't have any of the ramp-up time or built in pause to let the clutch disengage so it was pounding the motor pretty hard. In my third fight the shaft press fit / grub screws failed and in the fourth fight the hasty repair job gave up about half way through.  The rest of it worked decently well and many flips were had for a final 2-2 record.
Magneato vs Bot-a-rang
https://youtu.be/5GXj-AV_Ihg

Magneato vs Dorno
https://youtu.be/aYujS5Y573k

Magneato vs True Grit (should have won, got stuck upside down at the end because of the motor)
https://youtu.be/Ff4rUt550Yo

Magneato vs Uberclocker
https://youtu.be/0uv3AAgV4fo

I also got to help kyle with Congo, the chair-swinging sportsman bot. He helped me keep Magneato working so I figured I'd pitch in as a guest driver. I forgot to hit record on one of the Congo fights, and on another one there was no videographer, just a tripod and my camera, so the footage is pretty weak.

Congo vs Uberclocker (note the extra chair in the arena for Uberclocker to use)
https://youtu.be/VQwOQtN1LZQ

Congo vs Iron Golem (old fashioned slug fest)
https://youtu.be/9tKcuEv80Gc

As for motorama - I totally didn't realize the registration was already up. Life's been pretty busy lately and I just spaced out. I put a reminder on my calendar for round 2, so I'm still hoping I can get the sportsman in. Triggo is trashed after last year so I probably won't have a full combat 30. Thanks for the interest :)

-Zac

2
Progress Reports / Re: Revelation Robotics
« on: October 06, 2017, 03:13:28 pm »
What you describe is very close to what I was going to recommend if using off the shelf parts. Hope to see it in action in person.

Zac

3
Progress Reports / Re: Team Brain Damage
« on: September 29, 2017, 10:42:04 pm »
It is .25 inch titanium. I was bending the .25 6061 aluminum angle I used on the much less powerful first version. It was formed by whyachi. A well braced .25 aluminum could work I think.

Zac

4
Progress Reports / Re: Team Brain Damage
« on: August 26, 2017, 10:02:34 am »
Got my tickets in the mail. Looking forward to the event.

I don't think I'll have time to do anything especially interesting this year, unfortunately. Spare time has just not been widely available lately. It's still going to be fun though!

-Zac

5
Progress Reports / Re: Team Brain Damage
« on: August 18, 2017, 06:36:50 pm »
I'm in now. Thanks for the reminder!

Zac

6
Progress Reports / Re: Team Brain Damage
« on: August 13, 2017, 12:37:00 pm »
 The board is definitely damaged. That is almost definitely the cause of the symptoms that I experienced. My trouble is figuring out how it happened and how to make that particular thing not happen again so I can find whatever the next failure in the system is.  Either way it should be fun, and I have a feeling Jerry Clark and it's gonna show me why pneumatic flippers driven by someone with a clue dominate silly fly wheel powered flippers driven by an old-school spinner builder.

7
Progress Reports / Re: Team Brain Damage
« on: August 12, 2017, 11:09:56 am »
I don't think I'll have any major mechanical upgrades to Magneato for Franklin. In the two fights where the control system was working properly it performed great. It self-righted reliably, was very mobile, and the trigger worked well.  The only thing I'd like to investigate more in the trigger is the arm position sensor. I would like to polish up the light-sensor mount (instead of the ghetto ziptie setup I did the day before the show) or maybe add an encoder or magnetic switch to the arm so I know when to disengage. I'm thinking something like this might work:
http://www.kr4.us/Magnetic-Door-Switch-Set.html?gclid=CjwKCAjwzrrMBRByEiwArXcw28uN1OJMyRSMGHK-B3yOiD8W8U8roYkwd5VdBZ269X5qd9d7WHPIyBoCNIIQAvD_BwE

As far as the problems getting the flywheel to work reliably, I'm 99% sure that is an issue with the Arduino nano control board. When I was trying to get it to work for Shuttle Launch I spent a few hours trying to debug a complicated failure behavior where it would work if only the throttle was plugged in, but as soon as I plugged the trigger channel into the receiver the throttle would go to zero.  I think something happened to the circuits inside the controller that's causing a bad connection somewhere.  I can just swap the nano out, but I need to figure out what happened. I doubt it was shock loading but it is possible.

My best guess is that it has something to do with electrical feedback from the giant magnet running the clutch. I think it might have eventually toasted my flyback diode and then proceeded to damage the rest of the control hardware.  I don't know enough about electrical engineering to even know how to test something like that. Anybody have any suggestions?  The magnet draws ~5A @ 18v when it is on, and is about a pound of copper windings. I'm guessing there is a very large voltage spike when I turn it off. It damaged one of the little toggle switches I was using during my tests before I put a little diode on the leads. Can somebody recommend a specific diode for this?

-Zac

8
Progress Reports / Re: Team Brain Damage
« on: July 18, 2017, 07:38:55 am »
Fight 2: Plan F vs Driving Practice - https://www.youtube.com/watch?v=iYXpeNEpCdo

Fights like this are the reason I tried the wedgelet. The blade I'm using doesn't get much bite unless it can get under somebody, and a smooth wedge is a problem. Right off the bat they teamed up and rolled me over, but since I fixed the blade binding thing I had no problem powering the weapon up to self right. It took some slamming but the motor is very powerful.  Naturally they immediately "jammed me up" again and then in all the pounding I lost a drive motor.  At this point I wasn't feeling very hopeful about the fight.  At the end I decided to spin down so that if they pushed me into the wall I'd bunny hop out, and the gambit worked. I flipped over and took off a tire. Then the other bot came after me and I popped a tire off there too. Still, I wasn't in control at all during this fight and the judges knew it - loss by decision.

At this point I was pretty down on the Kitbots 1000 RPM drive motors I was using. I lost one in each fight (left first, then right). The motors themselves are very electrically noisy, such that even with the caps on them driving around was causing the blade to kick on and off, and when I drive forward it messes with the throttle and I can hear the blade speeding up and slowing down. Mix in the busted gearbox from this second fight and I'm gonig to be looking elsewhere in the future. Kyle pointed me toward some of the ServoCity planetary motors (14:1 and 19:1 ratios) and the boxes themselves look much nicer. I'll probably give them a shot.

Fight #3 vs Land Shark - https://www.youtube.com/watch?v=b4m7H5ZDAdY
I figured I was in big trouble here. I just got beat up pretty bad by a pair of plastic-wedge beetles, so going against the low slung metal wedge of Land Shark was not looking good. I had to leave the wedgelet on, which made the bot drive poorly, but if I didn't get a bite on the wedge I was toast.

Miraculously I managed to get under the lip early on in the fight and then it wasn't nearly as effective as a wedge. That let me go on the offensive until I skiped over the dent and got hung up on the damage. I think he must have been having some battery or drive troubles because he never really pushed me much even when I was stuck on top. We had to be separated twice, but in this fight my drive motors held up the whole time and I was able to gnaw at the sides and back of the bot until time ran out. Win by judges' decision.

-Zac

9
Progress Reports / Re: Team Brain Damage
« on: July 17, 2017, 08:14:08 pm »
Ok, we're going to do these one or two at a time as I have spare time:

Fight #1 - Plan F vs Super Kamikaze - https://www.youtube.com/watch?v=BN2h_o1lyNc
This was a tough first round draw for me. Super Kamikaze bashed me up pretty badly last year and I expected nothing less this year.  His wedge also made it tough for my blade to get a bite and my little wedgelet made it tough to drive.  About 45 seconds in I ended up upside down in the corner and I thought I was in big trouble. Then he charged in and accidentally rolled over his own wedge. This left both of us with pretty limited mobility. The damage to the weapon axle caused the bearings to jam up a little bit which made self righting using my blade very difficult. The motor and controller are so over-spec that they managed it, but there's a little burn mark on the ti shaft where the housing of the bearing was rubbing on it.   I managed to get myself upright but lost a drive motor in the process. SK was bouncing around trying to self right too and I happened to get a lucky strike on his battery pack (despite being unable to really attack on my own) that knocked him out.

-Zac

10
Progress Reports / Re: Team Brain Damage
« on: July 16, 2017, 06:24:00 pm »
I also had some other videos from the event added to my channel for other bots:

https://www.youtube.com/user/robotdesigner/videos

-Zac

11
Progress Reports / Re: Team Brain Damage
« on: July 16, 2017, 06:23:24 pm »
I don't have time for a full write-up for now, but I'll give a quick summary. Jeremy and the Campbells are awesome. The event was a blast (heh) as always and I think pretty much everybody had fun. I was pleasantly surprised to get first place with my bot, which I did end up naming "Plan F".  There was a wedge multibot that ended up doing unexpectedly well by making it to the final in the winners bracket. They schooled me pretty well in my first fight but I managed to beat them in the final. I got a lucky hit on the battery pack against Super Kamikaze the first time I fought him but fared better on the second try. Seven fights in a day with one bot is a lot, but other than a couple of drive motors and a dinged up weapon shaft I took very little damage.

Here are the videos:
https://www.youtube.com/watch?v=BN2h_o1lyNc&list=PLATw5d_vDtZkTdW2VN-Zw1S2WzlQMNzRp

-Zac

12
Progress Reports / Re: Revelation Robotics
« on: July 13, 2017, 04:00:09 pm »
If this problem is intermittent it could be a loose wire or bad solder joint between the motor and controller. I know you said you got it fixed but if it comes back that's what I would check.

Zac

13
Progress Reports / Re: Team Brain Damage
« on: July 13, 2017, 07:19:33 am »
Yeah, they're only 1/8". It's what I had weight and material on hand for. Because of the way I packed all the guts in foam I'll probably feed my back end to a horizontal spinner instead of the blade, at least until I can get it slowed down a bit. 

The wedgelet is pretty great, but it bites into my rough OSB floor pretty badly and makes it hard to drive the bot forward. On Jeremy's floor (at least at the beginning of the competition) it should be ok. I can always take it off if it is too annoying.

-Zac

14
Progress Reports / Re: Team Brain Damage
« on: July 12, 2017, 10:50:42 pm »
I'm already using the coarse-est screw I could find in the 3/8" range without getting into the multiple-thread-start or ultra-preci$ion version. The larger diameter screws offer additional options but I'm not sure if coarse is better for that first start or not.  I may toy with the idea some more in the future, but for Bot Blast I'm definitely not looking to do anything else that might not work. I've got to have a bot that can at least enter, and a barely-adequate drive system with no weapon is too lame for me to stomach unless I have to.

Sooo... In the last two nights I added a weapon to the platform and it actually came out super well.  There's a ton of empty space in the frame so I moved all the guts to the back and added a bunch of padding. The weapon mount is pretty weak but otherwise everything is actually well beyond me expectations for a two-night retrofit. Here is the catch-up build report
https://plus.google.com/photos/107279152885550274671/album/6433529956027270705/6442082293372338194

And some videos of the final version of the bot. Tomorrow is a frisbee game then packing on Friday. I'm getting pumped!
spin / drive
https://youtu.be/cKtuQWrxn50

self-right (that's a lot of motor!)
https://youtu.be/vDUzSqNpyi8
-Zac

15
Progress Reports / Re: Team Brain Damage
« on: July 11, 2017, 10:14:40 pm »
Thanks, I agree that the concept has a chance to be very cool. I spent most of this project trying to get it to spin faster because of the small size of the linkage I was using. In a bigger robot, with significantly more travel on the arm, the RPM required might be much lower to get the target tip speed out of the flipper. I think a lower RPM combined with a more reliable trigger mechanism than the silly servo-crank setup I have here could be a winning combination.  I have some even crazier ideas with it long-term but for now I'm a little worn out on the whole thing so they'll have to wait.

I spent tonight retrofitting the frame with an alternative weapon. I toyed with several different flavors of what I could do in 8 hours of build time with the parts I have on hand. Fortunately for me "the parts I have on hand" is a fairly extensive list, including twenty or so timing belt lengths, a half dozen pulleys, three or so spinning weapons in the right size range, and lots of motors and controllers to choose from.  With the lathe, mill, and random material stock I have on hand it was a question of what I could attach to the current frame.  I really wanted to do a horizontal midcutter with Devour's blade but I'm pretty sure the 1000 RPM drive gearboxes would explode from the recoil forces.  I opted to set devour's blade up in a vertical configuration because I already had it mounted to a hub/pulley assembly and had the motor, belts, and pulleys in the right lengths to fit it.  All I had to do was make a pair of weapon rails to support it and steal a hinge pin from Magneato for the blade axle. 

I'm going to remake the top plate tomorrow and move some of the guts around to be as protected as possible then I'm done.  Hopefully it has enough oomph to self right the bot (I bet it will with the simonk software).  If not, then I'll just try to keep it running and hope for the best.  I'm reasonably happy with how it fits in for this late in the game and it looks like the weight will be right on. I might have to take a little of the frame material out but it's going to be very close. I forgot how much simpler regular spinners are when you just ignore all the hard details :)

-Zac

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