SPARC Forum

Tech => Progress Reports => Topic started by: rumham on June 02, 2017, 04:44:30 pm

Title: Team Thrasher / Sunny Robotics
Post by: rumham on June 02, 2017, 04:44:30 pm
Hello,

Linked below is a brief history of my team and the build report of Rum Ham XL my 3lb bot.

Build report:
http://imgur.com/a/zp6S3

Videos:
https://www.youtube.com/watch?v=CoaTV_VJ8OU&list=PLIkQKO7gRmwM8emBHAa74N7Ib6dMKEibX

(http://i.imgur.com/ePPF4jw.png) (http://imgur.com/a/zp6S3)

Title: Re: Team Thrasher
Post by: zacodonnell on June 18, 2017, 09:36:17 am
I really enjoyed your build report. My first ever live competition was when I was 15 at the rc&g in Pittsburgh and I might even remember your bot. Man that was a long time ago!  I'm glad you're getting back into the madness and I really like how you did the weapon mount there.

Zac
Title: Re: Team Thrasher
Post by: rumham on June 22, 2017, 01:46:34 pm
Thanks Zac. I'm a big fan of your robots, especially Magneato.
Title: Re: Team Thrasher
Post by: rumham on October 26, 2017, 06:29:29 pm
Here is the build report of 'The Undisputed Champion' my 30lb flame throwing powerwheels!

Build report:
https://imgur.com/a/Cr7WB

Videos:
https://www.youtube.com/playlist?list=PLIkQKO7gRmwN4_VrNRBQLdgyK1lbG6UGW

(https://i.imgur.com/XYf1Mr7.png) (https://imgur.com/a/Cr7WB)
Title: Re: Team Thrasher
Post by: rumham on November 02, 2017, 05:16:54 pm
Here is an update for RumHam XL. These are the changes I made for AVC 2017.

Build report:
https://imgur.com/a/UqyLP

Best fight from AVC:
https://youtu.be/Xi-mzxQBKis

(https://i.imgur.com/FhHBc4o.png) (https://imgur.com/a/UqyLP)
Title: Re: Team Thrasher / Sunny Robotics
Post by: zacodonnell on January 14, 2018, 11:10:17 am
Very cool. Has it fought any midcutters? The design is a little closer to the first undercutter I ever saw in person (http://www.lazytd.com/rc/rcg/hworf2.jpg) than the more common designs you see these days. Seemed nice and reliable in that video.

-Zac
Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on January 15, 2018, 11:25:46 am
Very cool. Has it fought any midcutters? The design is a little closer to the first undercutter I ever saw in person (http://www.lazytd.com/rc/rcg/hworf2.jpg) than the more common designs you see these days. Seemed nice and reliable in that video.

-Zac

I haven't fought any midcutters or even traditional horizontal spinners yet. The limited weapon reach would likely put me at a disadvantage. This design has however proven to do really well agents non wedge vertical spinners and drum bots.   
Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on January 15, 2018, 11:48:21 am
Parts back from water jet. 3 ant weapons and 3 beetle weapons. all 3/8 S7. The ant weapons will be for a yet to be designed pizza slicer clone. The beetle weapons will be for the new rum ham. I still need to CNC machine the NTM v2 motor housing shape into the beetle weapons before heat treating.

(https://i.imgur.com/xAdk771.jpg)
 
Title: Re: Team Thrasher / Sunny Robotics
Post by: Koolaid64 on January 15, 2018, 08:47:52 pm
Phew those are some thin cross sections.  Keep us posted on how they hold up.

-Kyle
Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on January 16, 2018, 12:42:36 pm
Phew those are some thin cross sections.  Keep us posted on how they hold up.

-Kyle

Fingers crossed.
The ant weapons look the way they do because I had very little space left on the S7 stock before waterjet. Two of ant weapons were actually cut out of the space in between the spokes of the disk. The disk design resulted from the need to save weight. I really wanted to use 3/8 material but making a disk weigh less than one pound at 7.5'' was really difficult. The result was a really skinny disk with two spokes. The two spokes did however allowed me to make more ant weapons so that was a plus. Will the ant weapons and beetle disk break? Maybe; but I can always fall back on the bar for the beetle. I don't think the bar is going to break.
Title: Re: Team Thrasher / Sunny Robotics
Post by: Infernaltank on January 16, 2018, 06:14:44 pm
Are you coming to Motorama this year? I'm really interested in seeing this bot if you are. I'm really interested in building an undercutter.
Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on January 17, 2018, 10:39:35 am
Are you coming to Motorama this year? I'm really interested in seeing this bot if you are. I'm really interested in building an undercutter.

I will be at Motorama this year but I wont be bringing the undercutter. I don't expect to have it finished by then. It should be finished for Robogames. For Motorama I'm just bringing my prototype plastic ant 'bird law'. It should make for great cannon fodder.

Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on March 07, 2018, 04:49:10 pm
Here is my build report for Bird Law my plastic ant I took to Motorama 2018

Build report:
https://imgur.com/a/YNWrk

Videos:
https://www.youtube.com/watch?v=Qjwwdo41_rQ&list=PLIkQKO7gRmwOvs8guNn66k913Ze-D1YDs

(https://i.imgur.com/lNE9Zfw.jpg) (https://imgur.com/a/YNWrk)
Title: Re: Team Thrasher / Sunny Robotics
Post by: zacodonnell on March 08, 2018, 08:32:02 pm
It took me a while to figure out how the whole thing worked, but I think I've got it now. Basically the timing belt on the large rear axle turns a jack shaft in the middle of the bot, which drives a gear pair for the claw. When the claw can't rotate anymore because it grabbed somebody or hit the end of travel, the gears can no longer rotate. This means if you keep rotating the pulley on the back axle the timing belt is stuck, so the top of the timing belt will become a winch cable that pulls the whole arm assembly around the rear pulley/axle.

That's pretty clever! The mechanical (dis)advantage of such a long lever arm means the belt/chain you're using as a tension member better be pretty stout.  As you scale the design up you might have to go to some pretty serious chain to make it work. While I enjoy such projects more than most people, I do have to ask if you think all that chain/pulley/bearing stuff works out to be more efficient than a secondary clamping motor for the claw. Especially as you scale up I think it will be diminishing returns pretty fast.  Can't beat the coolness factor though!

I think you should totally build a sportsman version. When you do, it can hang out with Magneato in a competition for most craziness in the box at once.

Thanks for taking the time to do a build report and picture rundown

-Zac
Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on March 12, 2018, 05:34:22 pm
As you scale the design up you might have to go to some pretty serious chain to make it work. While I enjoy such projects more than most people, I do have to ask if you think all that chain/pulley/bearing stuff works out to be more efficient than a secondary clamping motor for the claw. Especially as you scale up I think it will be diminishing returns pretty fast.

Thanks for the kind words Zac! I'm going to try and keep just one motor for the lifting and clamping for larger builds, mostly for the coolness factor. I like all the gears and pulleys required to make it work even if it's not the most practical.

--Luke
Title: Re: Team Thrasher / Sunny Robotics
Post by: zacodonnell on March 13, 2018, 07:30:03 am
 You are speaking my language. Enjoy the challenge

Zac
Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on May 04, 2018, 01:21:16 pm
Here is my Robogames 2018 update for 'Rum Ham' the 3lb undercutter.

Build report:
https://imgur.com/a/ycipMwR (https://imgur.com/a/ycipMwR)

Disk machining video:
https://www.youtube.com/watch?v=Sbn0RFelWXA (https://www.youtube.com/watch?v=Sbn0RFelWXA)

(https://i.imgur.com/JPy3gI2.png)
Title: Re: Team Thrasher / Sunny Robotics
Post by: zacodonnell on May 05, 2018, 10:33:23 am
That's a fun video. I haven't seen many "how I did it" walkthroughs like it. Machining the motor pattern into the disk is a great way to get a low-profile high torque transfer connection. I've considered something similar with an outrunner before but the can shape is so seemingly random between them (and even between runs) that I never pursued it. I like the way you built in some potential adjustment for the variation.

-Zac
Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on May 07, 2018, 11:18:59 am
Machining the motor pattern into the disk is a great way to get a low-profile high torque transfer connection. I've considered something similar with an outrunner before but the can shape is so seemingly random between them (and even between runs) that I never pursued it. I like the way you built in some potential adjustment for the variation.
-Zac

This motor pattern was a lot trickier to reproduce than old style. I have to thank Brandon Wiebe for providing the motor model we used for the new weapons. For the old disk I found the motor files on grabcad.com .
--Luke
Title: Re: Team Thrasher / Sunny Robotics
Post by: Infernaltank on May 07, 2018, 11:42:10 am
Thanks for the build report.

Bummer you didn't do well at Robogames but hopefully you'll do well later this year.
Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on March 05, 2019, 03:20:29 pm
Hey everyone. Here's the build report for Rum Ham XXX my featherweight that competed at Moto 2019.

Build/Event Report
https://imgur.com/a/UPk68bX (https://imgur.com/a/UPk68bX)

(https://i.imgur.com/cV0sdnI.png)

For more frequent updates like the team on Facebook.
https://www.facebook.com/SunnyRobotics/ (https://www.facebook.com/SunnyRobotics/)
(https://i.imgur.com/XtjTetz.png)

--Luke
Title: Re: Team Thrasher / Sunny Robotics
Post by: zacodonnell on March 17, 2019, 03:17:16 pm
I enjoyed reading through your build report. It's fun to see somebody else publishing them in this format.  I have to admit when I heard about a bar direct driven off of a motor like that I expected the magnets and shaft to break on the first hit. After reading the build report I see that a lot of effort was put in to keeping those parts alive. It's awfully tough with that much energy going through them though... That bearing mount setup on the blade is some serious kinda project!


You mentioned problems with the Castle controller. I have been running Castle gear on my 30s for a while now and I like the beefy heatsink, data logging, and reliability I've had with them. I did blow the leads off of an ICE-100 one time when a belt jammed at spinup. I emailed the company to get the half-price replacement and they said "it shouldn't do that, we'll send you one for free".  They've been pretty solid since then for me. The data logging has been really useful for motor/battery sizing.

I have also had the experience of scraping epoxy off of motor magnets with a screwdriver. It can be quite a pain if you get it in the wrong place when trying to lock the magnets in :). I hope you didn't get pinched when you were working with the magnets - they can be pretty strong in a motor that size.

I like how you start with "Wiring my Rum Ham XXX was a pain" and then later on "Zac's new FBS...glad I didn't have to wire this".  When I read the first comment I thought "I feel your pain" and then hwen I got to the second one I laughed aloud.

Very cool stuff
-Zac



Title: Re: Team Thrasher / Sunny Robotics
Post by: zacodonnell on March 17, 2019, 03:28:51 pm
I have very limited experience, but have been pretty unimpressed with the maxAmps batteries. On a heavyweight project with a few of the Canadians we were running them at Robogames a couple years back and they failed way, way before their specs said they would.

Were you able to measure how much power you actually got out of them before they ran flat? I'll bet the peak current draw with the sad motor winding was pretty epic, but in normal use do you know how much it pulls?


-Zac
Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on March 18, 2019, 12:38:59 pm
I have very limited experience, but have been pretty unimpressed with the maxAmps batteries. On a heavyweight project with a few of the Canadians we were running them at Robogames a couple years back and they failed way, way before their specs said they would.
Were you able to measure how much power you actually got out of them before they ran flat? I'll bet the peak current draw with the sad motor winding was pretty epic, but in normal use do you know how much it pulls?
-Zac

Hey Zac,

I actually wasnít able to use the MaxAmps batteries for the event; I accidently left them on the shuttle bus at the airport. Fortunately my buddy Pete had extra batteries for 60 Seconds of Glory that fit. These batteries were Turnigy Graphene 2200mAh 4S 45C. Running at 8S instead of 10S helped put the weapon in the 200mph range. During safety the tachometer said it was spinning at 205mph so we just had to bump the throttle down a tiny bit.

Iím not really sure how much current the weapon usually draws. I was surprised to learn that the Castle Talon 120 HV does not have data logging. But it draws a lot of current. My match with Crippling Depression lasted 47 seconds and the weapon spun up only three times. After that match the battery charger put in 750mah worth of capacity, so the batteries are way undersized.

Iím working on ways to reduce the current draw and or increase capacity without building a new frame. I have extra weight and width to spare but not length. Higher capacity batteries seem to all be around 130mm long and I just donít have room for that. Iím currently looking at the https://www.maxamps.com/lipo-2800-5s-18-5v-battery-pack as itís the highest capacity battery I can find thatís ~108mm long. Compared to what I was running at moto 2.8AH@10s should give me about 59 percent more watt hours of power. I would still have to keep the weapon spinning around 200mph for an apples to apples comparison. This still wouldnít be enough power to run three minutes hard but it would be better than what it currently is. Ideally I would rewind the weapon motor to a lower KV so at 10s input voltage it naturally spun the weapon at 200mph (vs 300mph) but Iím not sure Iím ready to take on that project. I have a blown weapon motor so thereís not much to lose other than the time it takes to rewind the motor.

Iím also considering running the drive off its own battery. I think I can get another small battery and power switch to fit in the bot if I replace the massive drive VESCís with some hobbyking 80a ESC.

--Luke
Title: Re: Team Thrasher / Sunny Robotics
Post by: zacodonnell on March 18, 2019, 10:38:28 pm
The SimonK red brick 70A controllers have been rock solid for me on drive in the sportsman. I'm running 4x Afro 30A escs in Hyperpolarized (with four motors) and it is way faster than the shell drag will let me control. They don't even get warm.  It sounds like you're way overkill on your drive ESCs to me, and that should free up space as you say.

I feel your pain on fitting stuff in. Darn this optimization stuff..

-Zac
Title: Re: Team Thrasher / Sunny Robotics
Post by: rcjunky on March 18, 2019, 11:12:01 pm
agreed, running a small lower voltage pack for drive with rb70's or aerostar 60's if you run 4s should result in more reliable drive. I know I complain a lot about running dual voltage since it adds a lot of wiring, it is great for some things.
Title: Re: Team Thrasher / Sunny Robotics
Post by: rumham on September 10, 2019, 03:41:22 pm
Hello Robot Builders! Here's the build report for Rickety Cricket my 6lb gyro walking beetle

Build/Event Report
https://imgur.com/a/8MFkRu6

(https://i.imgur.com/JRPTboy.jpg)

--Luke
Title: Re: Team Thrasher / Sunny Robotics
Post by: zacodonnell on September 22, 2019, 08:59:26 pm
This is a fun project. I appreciate the write-up and sharing it with the two other people who exist outside of facebook :)

-Zac