SPARC Forum

Tech => Progress Reports => Topic started by: satacoy on June 03, 2015, 10:30:55 pm

Title: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on June 03, 2015, 10:30:55 pm
I'm starting to acquire parts for a new antweight.  Progress will be slow, details will be scarce.  It will be a "filler" project to work on while I'm finishing up larger projects.

(http://www.teamcosmos.com/SenseiAnt/Media/pop.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/pop.jpg)

I'm still missing a weapon motor and controller, but have most of the other interesting bits above.

Pete - Team Cosmos
Title: ESC Test
Post by: satacoy on June 07, 2015, 02:07:42 am
I did a quick test of the motor driver that I'm using.  Both the Maxon and the Silver Spark seemed to do well with it.  I'm still debating between the two motors.  Silver Sparks are cheap and available, but the Maxons are smaller, faster, and nicer.

(http://www.teamcosmos.com/SenseiAnt/Media/ESCTest.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/ESCTest.jpg)

Pete - Team Cosmos
Title: Raw Aluminum
Post by: satacoy on June 11, 2015, 12:44:42 am
I've cut the major pieces out of some 3" X .75" aluminum bar.  I'd forgotten how much I need a bandsaw, the hacksawing got a bit tedious.

The raw pieces weigh in at 1.5 pounds.  It'll be interesting to see how much of that ends up on the garage floor.  Hopefully most of it.

(http://www.teamcosmos.com/SenseiAnt/Media/rawAl.jpg) (http://"http://www.teamcosmos.com/SenseiAnt/Media/rawAl.jpg")
Title: Re: Team Cosmos - Sensei Ant
Post by: Lucas Grell on June 11, 2015, 12:49:02 am
So, do you have an actual plan for this, or just building as you go? I'd love to get an idea of what you're building, but it's still cool just seeing parts get made.
Title: Re: Team Cosmos - Sensei Ant
Post by: satacoy on June 11, 2015, 10:06:56 am
Oh, I have a plan.  Muah ha ha ha.

I have the thing 90% CAD-ed up, but due to my old 2D CAD program I don't know what kind of weight I'm looking at.  It's more exciting that way.

I'm following the Cosmsos pattern of the past with the slow reveal.  So you'll have to settle with watching parts slowly be made.

Pete - Team Cosmos
Title: Re: Team Cosmos - Sensei Ant
Post by: Lucas Grell on June 11, 2015, 10:11:11 am
I cry every time man ;)

Really though, I do appreciate how well you document most of your builds, it's always good for inspiration.
Title: Motor Mounts
Post by: satacoy on June 11, 2015, 11:19:41 pm
I managed to squeeze in a few hours in the garage to make some tiny motor mounts.

(http://www.teamcosmos.com/SenseiAnt/Media/mounts.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/mounts.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Sensei Ant
Post by: Lucas Grell on June 12, 2015, 11:11:15 am
That reminds me- I've been meaning to ask what Maxons people use. Also, with belt drive, would they be sufficient for a beetle?
Title: Re: Team Cosmos - Sensei Ant
Post by: satacoy on June 12, 2015, 01:31:30 pm
I have three of these small Maxons, and seven larger ones that were donated to me from the BaneBot guys back in the day.  I don't know the stats on them, or if they're even available any longer for reasonable prices.  They're really nice motors, the quality is impressive.

I've never tried these smaller ones, but they seem tiny to be pushing 3 lbs around.  I have the larger motors in the ill-fated Auditor beetleweight.  They would have worked fine there, if the weight distribution would have been better.  I also used the same sized motors in Sister Christian, although she was only 2 lbs.

Pete - Team Cosmos
Title: Day 3
Post by: satacoy on June 13, 2015, 10:53:51 pm
Got a few more pieces made today.  The basic shape is becoming more obvious.  I'm down to 1 lb 2 oz of aluminum, still a long way to go.

(http://www.teamcosmos.com/SenseiAnt/Media/Day3-1.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/Day3-1.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/Day3-2.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/Day3-2.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Sensei Ant
Post by: TeamAstroBot on June 17, 2015, 12:34:24 pm
Looks like your making some good progress! I must say it is refreshing to see you testing the waters so to speak by building a new bot.

My first year as a builder my high school's bot Son of X got paired against Corona at Moto. To this day that match is still my favorite, I chuckle every time I watch it!
http://www.teamcosmos.com/moto05/CoronaVsSonOfX.wmv

You guys provided the friendly encouragement to come back and do better next time.
Title: Re: Team Cosmos - Sensei Ant
Post by: satacoy on June 17, 2015, 01:18:32 pm
It's amazing to think that was 10 years ago.  Glad to hear that it was a positive experience.  I always worry that we crushed a few childhood dreams by beating up on the other bot too much.  But that's part of the game, it's a good lesson to learn.

I'm hoping to try some novel control concepts with this bot.  It may end being overweight and be more of a test platform than a true competitor, but it'll be fun either way.

Pete - Team Cosmos
Title: A shift in direction
Post by: satacoy on July 01, 2015, 11:25:07 pm
I've decided to take the beginnings of the new bot, and use most of the same components for a new version of Angry Accountant.

The SparkFun competition gave me a few ideas for improvements on the basic design that should make her bomb proof.  Plus, I was having a hell of a time getting all the wacky new ideas to fit into a 1 pound bot.  I'll instead use some of those on a new bot to be built sometime in the future.

I've accumulated a decent pile of parts.  It's been fun re-visiting McMaster, OnlineMetals, HobbyKing, etc. 

(http://www.teamcosmos.com/SenseiAnt/Media/hobbyking.jpg)

I have a few weapon motors to do some testing with, along with various battery sizes.  One thing I learned at the SparkFun competition is that I was using much too large of a battery at 610mAh.  None of the weapon motors are too crazy, I'm more interested in resiliency rather than insane-o weapon.

Machining should start in earnest in a week or so.  Can't hardly wait.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: Jeff Gier on July 03, 2015, 11:34:55 am
Brushless AA seems pretty scary!  Keep us posted. 
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: zacodonnell on July 04, 2015, 08:33:59 pm
Sounds like the filler projects has given you the bug a little bit...

I was always impressed by the work you guys did, but you stopped competing right about the time I got past being a clueless newbie. Sure would be cool to see you come out to moto again some time even though I know it's awfully far.

-Zac
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on July 05, 2015, 05:56:31 pm
Hey Zac!

I've certainly got sucked back in a bit with the new TV show and a local competition. 

I faintly remember meeting you at a Motorama or two.  I've enjoyed following your recent projects, they're always interesting and well documented.

It'd be great to make it back out to Moto some time.  It does fall at a bad time of year for me, which makes pulling the trigger a bit harder. 

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: mathias on July 05, 2015, 05:58:06 pm
Autonomous with that Teensy and the IR range finders?
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on July 05, 2015, 06:03:53 pm
>> Autonomous with that Teensy and the IR range finders?

That was the original plan, I'm switching to (almost) purely manual driving for this iteration.  I'll try the autonomous route with a larger bot.  I have some ideas that I'm keen on trying.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: mathias on July 05, 2015, 06:13:19 pm
Cool. Are you going to keep the Teensy and use some sort of Bluetooth connection by any chance? I've been thinking about using a LightBlue Bean that I have (https://punchthrough.com/bean/) as a receiver and controller. It'd still need a motor controller, but it has an accelerometer, which could be used for some simple safety stop stuff (if flipped, too violent of an impact, etc.) And driving with a phone just seems like a funny idea :-)

Related, did you find the Sparkfun motor controller (https://www.sparkfun.com/products/9457) useful? Obviously it's lacking the smarts that something like a TinyESC has built in for motor protection, but at $8.95 it is cheaper than two tiny ESC's by a long shot.
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on July 05, 2015, 06:24:08 pm
Good guesses, that's exactly what I'm planning on doing.  I'm going to use Bluetooth to transmit data back to a computer, have the computer make the decisions, and then send commands back to the bot.  I had a 6DOF IMU in there too to help w/ dead reckoning.  Instead of trying to code up all the logic on the pro-mini, it would just collect the data and transmit it.  It'd also handle commands coming back from the laptop (left motor 50%, right motor 25%, turn weapon on, etc).

I've played around with the motor controller a bit, it seems to handle the maxon motors fine, albeit with no load.  Once I get a frame in place I'll do some better tests.  I can swap in other controllers if that one proves too puny.

So I'm leaving out the sensors and IMU on this iteration, but am going to try the bluetooth/motor controller/pro-mini on this iteration of Angry Accountant.  Since I have antiquated FM transmitters/receivers, this seemed a more interesting route than just buying a new 2.4ghz radio.  Should be cheaper/smaller too, if things work out.  I picked up a SparkFun joystick setup, so that'd also plug into the laptop for this iteration, the laptop would do mixing, and broadcast to the bot.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: mathias on July 05, 2015, 06:47:35 pm
Really cool! I'm going to be watching this thread with some interest -- I think combat robots with some onboard smarts are an interesting development of tiny, powerful processors and lightweight batteries. And options other than  If you end up putting the code for the Teensy online on Github or similar, or if I can help out at all (my background is in programming)
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on July 06, 2015, 01:20:08 am
I managed to get several hours in on the mill this afternoon, made some good progress on the frame.  I'd forgotten the joys of machining on a hot summer night.  The haze of cutting oil smoke, the sting of the chips landing in your flip-flops.  Ah, the memories...

(http://teamcosmos.com/SenseiAnt/Media/Pass1Bot.jpg)
(http://teamcosmos.com/SenseiAnt/Media/Pass1Top.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: Lucas Grell on July 06, 2015, 01:30:03 am
Looks great!
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: mathias on July 10, 2015, 12:40:55 pm
Hey Pete,

I know you said you shelved the autonomous idea for now, but I wanted to share something I learned about.

While browsing the online store http://jsumo.com/ (which is a Robot Mini Sumo store in Turkey) I discovered that they're using these little IR sensors that work like logic switches: http://jsumo.com/shop/mz80-infrared-diffuse-type-reflexive-sensor/ They look to be a little bit more durable than the Sharp IR range finders, and they're good if you simply need to know "something is there or not in this range" rather than an actual range value. I found similar sensors for sale on Amazon for a few dollars less than the cheapest Sharp IR rangefinders: http://www.amazon.com/Geeetech-Infrared-proximity-compatible-Arduino/dp/B00AMC1V2C/

The other benefit would be that I think you can use a digital logic line interrupt in a microcontroller with these, so the main program loop doesn't have to "poll" each sensor for updates, it can simply respond when an input detects the opponent.

I'm not sure what their durability will be, but since they're mounted in a round hole, they should be easy to replace if damaged. Not sure what the actual weight is; Amazon lists the product weight (with whatever packaging) as 0.3 ounces so I'm going to assume quite light.

Thinking of using these as side and backwards sensors for both simplicity and durability of a sensor exposed on armor surface. Forward sensors might need to be something with more resolution than simply "Something is there" like the two IR range finders on the front of my mini sumo bot: the difference between their values allows the bot to know whether to turn left or right to meet the opponent as it approaches.
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on July 13, 2015, 11:59:20 am
Those do look interesting, although I wish they were smaller.  If I'm reading the description properly, they have a diameter of 20mm, which is a hair over the .75" thickness of the frame.  They're also quite long.  I'd be very tempted to do a simple "on-off" type of sensor if I could fit them in, but I think I'd have the same sizing issues as the Sharp sensors.  Something in the .25" to .50" size would be perfect. 

I spent some time on Digikey a while back looking at alternative sensors, but didn't really spot anything that looked better.

Regardless, thanks for passing the idea along.  They might make it into the slightly larger autonomous bot I hope to someday build.

Pete - Team Cosmos

Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: MikeNCR on July 13, 2015, 12:14:28 pm
Those do look interesting, although I wish they were smaller.  If I'm reading the description properly, they have a diameter of 20mm, which is a hair over the .75" thickness of the frame.  They're also quite long.  I'd be very tempted to do a simple "on-off" type of sensor if I could fit them in, but I think I'd have the same sizing issues as the Sharp sensors.  Something in the .25" to .50" size would be perfect. 

I spent some time on Digikey a while back looking at alternative sensors, but didn't really spot anything that looked better.

Regardless, thanks for passing the idea along.  They might make it into the slightly larger autonomous bot I hope to someday build.

Pete - Team Cosmos

This page might be worth a look when it comes to autonomous combat bots- http://www.wa4dsy.com/robot/scary-go-round
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on July 14, 2015, 12:21:20 am
Summer is in full swing, but I managed to find a few hours to do a bit more machining.

I milled a few features into the frame side.  There's a hole for the motor, a dead axle, and a slot for the keyed "wing".

(http://teamcosmos.com/SenseiAnt/Media/wing1.jpg)

Here's the motor and dead axle installed.

(http://teamcosmos.com/SenseiAnt/Media/wing2.jpg)

Next are a few shots of the wing, motor, and dead axle in place.  Feels very solid, and should protect the motor and belt well.

(http://teamcosmos.com/SenseiAnt/Media/wing3.jpg) (http://teamcosmos.com/SenseiAnt/Media/wing4.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on July 28, 2015, 12:36:09 am
Another fun evening of removing aluminum.  I started at 8.4 ounces, ended up at 3.6.  Still some sanding of outside curves to do, but the main body is getting close.

(http://www.teamcosmos.com/SenseiAnt/Media/rough1.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/rough2.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/rough3.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/rough4.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on July 28, 2015, 11:43:15 pm
Got the frame sanded and cleaned up a bit tonight.  Starting to look like a real robot.  The raw aluminum for the frame started at 1 pound, 8 ounces, and ended up at 5.4 ounces.

(http://www.teamcosmos.com/SenseiAnt/Media/fullframe.jpg)

(http://www.teamcosmos.com/SenseiAnt/Media/fullframe2.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: mathias on July 28, 2015, 11:49:18 pm
Belt drive for everything?
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on July 29, 2015, 12:00:11 am
Yep, no direct drive this time around, and all pulleys will be more or less shielded too.  Hoping to make it bullet proof.  Invertability remains a problem.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: Koolaid64 on July 29, 2015, 12:01:20 am
so much metal. looks awesome
-Kyle
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on July 29, 2015, 12:06:55 am
so much metal. looks awesome
-Kyle

Angry is so very metal.

I could have made a few bits out of polycarb, but I like the idea of going over the top with the aluminum.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on August 01, 2015, 07:28:07 pm
Not a lot of progress, more of a test fit of some components.  I cleaned up the old weapon assembly off of the previous Angry, and plopped it in to see how things fit.  I'll be making a new one, but this at least lets me see what things are going to look like.

I also made some hubs for the tires, and threw the motors in too.  The electronics are going to be a tight fit, but I should be able to get them all in main bay, including the 260mAh LiPo.

(http://www.teamcosmos.com/SenseiAnt/Media/testfit.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: mathias on August 02, 2015, 11:45:55 am
It's looking mean!  ;D
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: Jeff Gier on August 04, 2015, 11:47:20 am
It looks like a beast!  I see a lot of features coming from lessons learned at AVC.  This is gonna be good.
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on August 05, 2015, 12:17:23 am
I've been playing around with getting pulleys and belts made.  I threw in a brushless motor and a giant speed controller.  I'm going for a fairly short motor so that invertibility should be manageable.

(http://www.teamcosmos.com/SenseiAnt/Media/armature.jpg)

Here's a spinup test.  I draw over 5 amps for a bit, which is all my power supply will provide.  However, once the blade is up to speed, things settle down to about 2.5 amps with this GWS motor.

http://youtu.be/fWYkB1qBT5A

I have a few more motors and speed controllers to test.  I'll see what plays the best together and fits into the smallest area.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: Lucas Grell on August 05, 2015, 12:33:28 am
Looks nice- What's the plan for the blade? Going to try something different, or keep a similar design to the old one?
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on August 05, 2015, 12:45:10 am
I'm not sure which direction I'll go there.  I could make a similar blade, but make it about .5" longer.  Or I could do some single tooth type of setup.  I'll probably leave that design up in the air until I get the thing driving, covers made for everything, etc.  That way I'll know how much weight I have to play with.  With the current setup, I'm about 1 oz under weight.

I no longer have a programmable heat treating oven, so I'll have to farm the hardening out.  I'm hoping to machine the blade myself, which would force me to keep the design pretty simple.

Pete - Team Cosmos
Title: Electronics Test Fit
Post by: satacoy on August 07, 2015, 04:55:04 pm
I'm starting to figure out how to cram all the electronics into the tiny bay.  I don't have all the components yet, so I'm dummying a few things up with blocks of wood.  If all the online sizes are correct, I should be able to squeeze everything in there, but there will be some crazy soldering going on.

I also got the belts and pulleys made.  All looks good there.

(http://www.teamcosmos.com/SenseiAnt/Media/elfit.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: Lucas Grell on August 07, 2015, 05:31:46 pm
Is the little block a fingertech switch? It's the size listed exactly. In fact, there's a CAD model showing it's exact dimensions. It can handle a silly amount of current, as well (more than a Deans connector :O).
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on August 07, 2015, 05:55:01 pm
You guys are good guessers.  That is the Fingertech switch, just ordered today when I realized I had room for it.

Underneath the micro-controller is another block that stands in for the Spider 12a brushless ESC.  I doubt the measurements on HobbyKing, their numbers seem to be off on a lot of things.  If it's bigger than stated, I can put a hump on the top plate to accommodate.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: Lucas Grell on August 07, 2015, 08:42:04 pm
So you're going to control it using bluetooth and the microcontroller even though you're not doing sensors and stuff? Seems like it'll take up more space that way. HK specs are usually pretty accurate for motor dimensions and stuff but I don't really trust electronics and batteries too much; I've had them be off in both directions, smaller and larger.
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on August 08, 2015, 03:47:00 pm
There's a few things working against using normal RC equipment:
Pete - Team Cosmos

Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on August 10, 2015, 12:28:43 am
I added a 7075 top plate today.  There's a few corners to machine down, holes needed for the power switch/LED/antenna, but it's a good start.  This thing is a brick, it feels ridiculously solid.

I have about 1.5 ounces left to play around with.  I'll use some of it for a motor cover, but want to wait until I test a few more motors before committing to a height.  I'm hoping a shorter motor will work, improve my invertability, and free up some more weight in the process.  I have one side project that might work well as an additional weapon, but I'd need at least 2 ounces.

(http://www.teamcosmos.com/SenseiAnt/Media/topplate.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: Lucas Grell on August 10, 2015, 02:55:39 am
It looks solid! Can't wait to see it with a new weapon! What size motors are you using for the weapon?
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: Coboxite on August 10, 2015, 03:04:29 am
Damn that's pretty.
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on August 10, 2015, 05:27:41 pm
The motors I'm playing around with all are 28mm in diameter, just varying the height of the can.  I'm shooting for about 2000 rpm per volt, with a 2:1 reduction, so I should end up around 7k rpm.  It feels about right when spinning up.  It won't be at the crazy end of the rpm scale, but enough to do some damage.  The goal with Angry has always been to come back for more until the other guy breaks, not necessarily a one hit kill.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on August 13, 2015, 11:52:49 pm
I managed to squeeze a belt cover under the blade.  Let's see those pesky drums knock my belt off now!

(http://teamcosmos.com/SenseiAnt/Media/beltguard.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: daggius on August 17, 2015, 06:46:04 pm
Looks nice.  What inspired the name?
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on August 17, 2015, 07:01:00 pm
My special lady friend happens to be an accountant.  And she's occasionally angry.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on September 20, 2015, 05:53:09 pm
Progress has slowed down a bit, but I'm making a bit here and there.

Here are the electronics wired up and working.  Things barely fit in the body, it's a tight fit.  Note the classic electrical tape, hopefully preventing shorts of any sort.

I can drive angry around via a telnet session, but that's pretty rough.  Next step is to write a test program so I can have more intuitive controls.  I'll post some video once I have that working.

(http://www.teamcosmos.com/SenseiAnt/Media/Electric.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on October 12, 2015, 11:07:10 pm
I added a motor guard with a bit of the weight I had left over.  Things are pretty protected at this point, have to admit that I'm happy with the design.  I have almost an ounce left for weight, I'm still toying what to do with that.  I still need a new weapon blade, weapon shaft, and a few holes in the top plate for power access and radio use.

(http://www.teamcosmos.com/SenseiAnt/Media/front75.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/rear75.jpg) (http://www.teamcosmos.com/SenseiAnt/Media/BottomSide.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: MikeNCR on October 13, 2015, 08:41:23 am
Might be worth putting some sort of cover over the bearing to keep arena crud out of it.
Title: Final Notes
Post by: satacoy on January 16, 2017, 12:34:56 am
I just realized I never really closed this topic up.

The electronics work on Angry 3 took a long time.  I switched from using Bluetooth to a normal 2.4ghz receiver.  It was smaller, gave me channel data on a single PPM line that I could decode with the Arduino, and didn't have any binding issues, unlike the Bluetooth module.  Soldering the drive ESCs, the brushless weapon controller, the Arduino, and the receiver into a tiny 1.3" X .85" X .65" cube was challenging.  I shorted something out twice, blowing up a few components in the process.  The third time was the charm.

I competed at the SparkFun AVC contest in September.  I had some driving issues, Angry didn't like to drive straight.  But she stood up to some big hits.  There was some cosmetic damage, but all-in-all did well, getting 3 wins and 2 losses.

I'm planning on heading to RoboGames in April to compete with her, and it sounds like another Ant/Beetle competition will be held in Boulder in April as well.

Meanwhile, I created a Team Cosmos Facebook page, and have been posting updates there.  You can find that here:  https://www.facebook.com/TeamCosmosBots/ (https://www.facebook.com/TeamCosmosBots/)

(http://www.teamcosmos.com/SenseiAnt/Media/finalweight.jpg)(http://www.teamcosmos.com/SenseiAnt/Media/FinalInternals.jpg)(http://www.teamcosmos.com/SenseiAnt/Media/AVCDamage.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: jamisong on January 16, 2017, 01:43:14 am
I love seeing nice and tidy electronics layouts :)

Looking forward to the next adventure! That should be moto right? :P
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on January 16, 2017, 11:08:17 pm
I'm getting more optimistic about making it to Moto, it looks like the timing will work out.  Just as a spectator though.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: jamisong on January 17, 2017, 03:40:52 am
I'll take it. Been looking forward to meeting you half my life :P
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on January 17, 2017, 11:48:19 am
I'll take it. Been looking forward to meeting you half my life :P

Don't get worked up too much, I'm not that impressive in real life.  :-)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: zacodonnell on February 27, 2017, 10:42:24 pm
Hey Pete, it was great to finally get to talk to you in person at Motorama.  I've been using the Team Cosmos KE calculator for a while (both the original version and the revamped version). I like to gauge my designs against the known performance of old designs, but with the shell spinners it is always hard to model the weapons accurately.  For the longest time I was never able to get the numbers my cad software produced to match the numbers you guys produced and tonight I finally figured out why: units are fun. 

The struggle has always been to figure out what the conversion factors were between what my software produced and what your page shows as the unit.  I think there may be a typo on the page. It lists the MOI of a part as MOI: -0.251 fp/s^2.  It could be that I just don't understand what that unit is, but it looks like foot-pounds per second squared, or maybe pounds of force per second squared. The trouble is that MOI is in mass-times-area units and there is no time component. Is it possible the cosmos calculator was supposed to say lb-ft^2? If I treat the value as that unit then my cad software (which produces values in lb-in^2) matches after converting the units.

-Zac
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on February 28, 2017, 01:24:04 am
Hey Zac,

First, I'm tickled that people are still using the KE calculator.  It's quite possible that the units are wrong, I faintly remember there being some debate on the proper units back in the day.  I'll see if I can dig up the old Delphi Forum posts on it.  Eventually it seemed everyone agreed they were correct, and I believe that I got the math and units out of Machinery's Handbook, but it's always possible that it's wrong.

Secondly, it was great chatting at Motorama, but we've met before, back in the day.  I distinctly remember taking this picture:

(http://teamcosmos.com/events/moto07/IMG_2111.jpg)

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: zacodonnell on February 28, 2017, 06:52:37 am
After re-reading my post (that I made well after I should have gone to bed) I realize my phrasing was bad. The math on the calculator works fine, it's just the label on the screen that I think is wrong. The KE calculation seems to be ok too.

You're right, we did meet way back then after Solaris beat up on my bot Scurrie. Such a long time ago now.

-Zac
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on February 28, 2017, 09:56:29 am
My phrasing was bad as well, I realize you're only talking about the unit label I'm using.  And my memory isn't that good, I remember talking to you in '07, but I don't remember fighting Scurry.

I couldn't find the old Delphi thread on the calculator.  I'm not sure if it was in the SubLight forum, the Battlebots forum, the RFL forum, etc.  I remember Eric Scott being pissy about the calculator, but then he was pissy about most things. :-)  I did get a kick while searching the forums on seeing old names and topics pop up.

Once I'm back in Boulder I'll dig out the handbook and see if I can understand why I used that label.  I bet you're right about it being off, I just want to look at the source one more time to see if I had a good reason.  I think I wrote that original calculator in like a day, didn't know javascript or the math behind KE, but just ran with it and it seemed to work.  The original version would only work on IE, if I remember correctly.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on March 11, 2017, 01:06:31 am
I found some time to crack open the Machinery's Handbook to see if I can make sense of the units.  According to the handbook, there are three types of Moment of Inertia calculations typically used in engineering:  Moment of inertia of plane area, Polar moments of inertia of plane areas, and polar moments of inertia of masses.  I followed the equations for that third kind, which are specified to be used in equations involving rotational motion.

For this type of calculation, the units are described as thus:  "If units are in the foot-pound-second system, the units are ft-lbs-sec^2".  That does differ than the label that I give it on screen of "fp/s^2".  I abbreviated this "ft lb/sec^2" on the original version.  According to the above quote, this would properly be labeled as "ft-lb-sec^2", or something similar.  This is equivalent to slug-ft^2.

But, that doesn't agree with your findings of a timeless unit.  The other two types of MOI appear to have units of Inches cubed.

So, I'm not sure what the right answer is.  I'll update the page to reflect ft-lb-sec^2, since that matches more closely my source material.

Pete - Team Cosmos
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: zacodonnell on March 11, 2017, 09:12:01 am
Thanks for digging in Pete. It is a useful tool regardless, and I've been using it for benchmarking robots for years. In fact, that and the online metals weight calculator (which also only worked in IE) were the only two bookmarks I had in IE for a long time. Now that I've got real CAD and you have updated this I can ignore my IE entirely :)

-Zac
Title: Re: Team Cosmos - Angry Accountant - A New Beginning.
Post by: satacoy on March 11, 2017, 12:07:22 pm
I feel good knowing that I've eliminated one small reason to keep IE around!  :-)

Pete - Team Cosmos