Team 67's incredible shooter
 

I've been watching 67's matches lately and haven't been able to keep my jaw off the ground at their shooter. I was able to pause a video frame and get a small glimpse of their shooter on Youtube. It appears they are using the orange 2 7/8" BaneBots wheels (a .8" thick one with a .4" on top). It looks like it's three wheeled.

Has anyone out there played with/against them who can testify to this? (Or maybe someone from the HOT team) I'm looking to find out what motors they are using and what reduction, if any.

We are running a three wheeled shooter with the same BaneBots wheels (expect with the "blue" density). We have three RS 550 motors powering it through Versa-planetary gearboxes. The first wheel that the Frisbee touches is a 5:1 and the second two wheels are running 1:1. Although we are happy with the set-up, we haven't seen anywhere near the same performance that HOT is getting out of theirs. Any information and advice is appreciated.

Thanks :)

Re: Team 67's incredible shooter
 

I suggest simply PMing Adam Freeman about this. He'll answer any questions you could possibly have about it.

Re: Team 67's incredible shooter
 

I'd love to see a response on this forum, if he stumbles upon it; I too am interested its specifics.

- Sunny G.

Re: Team 67's incredible shooter
 

I believe this is what you're looking for:

http://frcteam67.dyndns.org/HOTPhoto...t/IMG_0003.JPG

They have more pictures on their website:

http://frcteam67.dyndns.org/HOTPhotoAlbum/index.html

Re: Team 67's incredible shooter
 

Just PM Adam. He will tell you everything you want to know. :D

Re: Team 67's incredible shooter
 

Thank you for the responses, I've sent him a message. If anyone wants, would be happy to relay information when he responds.

Re: Team 67's incredible shooter
 

Make sure to ask him if 67 would be okay with you relaying information about their shooter. It's one thing to share with one person, it's another to freely distribute information.

Re: Team 67's incredible shooter
 

Sure thing.

Re: Team 67's incredible shooter
 

Thanks for the compliments. Our shooter is pretty good. I wouldn't say it's the best (I personally love 2169's shooter), but it will hold it's own with the best of them.

Shooter Details:
We are using the 3.875" banebot wheels with the orange rubber compound - - http://banebots.com/pc/WHB-HS4-398/T80P-394BO-HS4

It's set up for about a 1/2" of compression on the disk.

For the other side, we have a piece of 2" AL angle. It's got a piece of rubber (not sure what kind) glued to it too provide traction. The only other thing we did was tip about 5 degrees to try and keep the discs from walking out the top. We were trying to eliminate the curve on the shots, but it didn't help much and I think the curve is actually a benefit for us (harder to block).

For speeds we are running a AM-9015 on the first wheel with a pulley setup at 42T:12T ratio (~4500RPM). The next wheel is a Banebot 550, setup on a 30T:12T ratio (~7700RPM). The third wheel is also a 550 with a 22T:12T ratio (~10500RPM).

Each wheel is driven by it's motor, with it own timing belt pulley setup.

MXL Urethane Timing Belts and Pulleys:

http://www.mcmaster.com/#mxl-timing-...ulleys/=m9ecc1
http://www.mcmaster.com/#mxl-series-...-belts/=m9eclj

We used the 1/4" belts.

We run it open loop 100% for the FCS. The driver times the shots to get the correct rythem to try and keep it consistent.

I can't seem to figure out how to post pictures, so let me know if you have questions.

-Adam

Re: Team 67's incredible shooter
 

Thanks for the details. You could post the pictures to a site like imgur, and provide the link.

Re: Team 67's incredible shooter
 

I really appreciate it when the best teams in the world are willing to share info about their designs. I pay close attention.

Re: Team 67's incredible shooter
 

On 67's website at the end of every season, they provide technical notes on the robot. The notes show what they did, how they did it, and why they did it. It's not like they're dumping a full render of every piece of their machine, but I would argue it's one of the most educational and underutilized resources available to teams looking for what makes a multi-Einstein HOF Team "click".

Re: Team 67's incredible shooter
 

Yeah your probably right. The one picture linked above by fr05ty27355 pretty much shows it as well as the picture that I have.

It shows the pulley setup pretty well.

The top and bottom plates on the wheel part of the shooter are 1/8" waterjet AL. We had to find high speed 1/2" diameter bearings for the top, which are pressed into the bearing blocks on the top plate. The lower bearing are 5/16" diameter. I would of prefered larger, but I wanted to try to not add the weight of additional bearing blocks on the bottom too. So 5/16" was the largest we could go and still meet the RPM requirements (+10,000 RPM). So far so good. We lost a couple lower bearings on the practice bot, but I think those were more from being installed incorrectly.

I am planning to create another Tech Notes as soon as things with the robot settled down. Hopefully, I'll get a chance to do that sooner rather than later.

-Adam

Re: Team 67's incredible shooter
 

Nice showing out there today, looked awesome.

Why orange over green or blue for the wheels? Also how often did you change them out?

Re: Team 67's incredible shooter
 

Thanks!

The idea to use banebot wheels came from Allen Gregory and 3847's blog. We were originally trying to use colson wheels, but those transferred too much of the frisbee to the wheel quickly and shot very inaccurately. I emailed Allen and asked about how well their banebot wheels were holding up. He sent back pics of all three different compounds (green, orange, and blue). The green seemed to be worn down really bad, the orange and blue not so much. So we purchased both orange and blue.

The orange had much better grip than the blue. When we tried the blue we needed to squeeze the firsbee much tighter to get an accurate shot, even up close from the pyramid. The orange seemed to offer the best combination of wear and grip.

So far we have only replaced the lower rear wheel, about once per competition. We replaced one before Troy, one before MSC, and one before Eliminations today. All the other wheels are "original".

I think the shooter accuracy is actually falling off from what it was at Troy and early MSC, so we might replace all the wheels when we get to Champs just to be safe.

-Adam

Re: Team 67's incredible shooter
 

Thank you for the responses Mr. Freeman, I appreciate your openness. We've been very inspired by your team in the past and this year is certainly no different. :D

Re: Team 67's incredible shooter
 

Thanks for sharing this information... I hope when the season is over other teams will share these numbers as well and what methods they used to work out how to come to these decisions.

Re: Team 67's incredible shooter
 

Good to know.... We've been using the green wheels all year (not sure if there was any particular reason), and we did see a LOT of wear after our first event Northern Lights - even having to replace all 3 mid North Star. We may get a hold of the orange and blue ones to try them at champs (or at least have them on hand).

Re: Team 67's incredible shooter
 

What do you like best about 2169's shooter? I couldn't seem to find a picture of it anywhere.

Re: Team 67's incredible shooter
 

I just liked the way it shot. It had a very high release point, that was very hard to block.

I'm not sure I saw it miss in any of the matches that I watched from the Colorado Regional eliminations.

I haven't really seen pictures of it....just videos from the webcast. I will definitely have to check it out in St. Louis.

Re: Team 67's incredible shooter
 

I think it's interesting how differently the two long-range shooter whose shooters I've seen approached the FCS concept. While 67 is using three banebots, 195 has a GIGANTIC wheel on a circular shooter. It's awesome.

Re: Team 67's incredible shooter
 

I can only talk to what we did. In our case, we were trying to keep the weight of the shooter down as much as we could, since we were going to be tipping the robot back to climb up the corner.

I'm not really sure how much weight savings we actually achieved, since I believe the shooter assembly (shooter, plate, frame, etc..) ended up weighing about 15lbs. So when you add up all the bearings, bearing blocks, wheels, and other parts the weight went up pretty quickly.

We prototyped multiple shooter configurations, but the linear style offered the best performance for us, given the packaging configuration we had to fit for the climber.

Once we added the third wheel, we really started to get the FC distance we needed. Without it (double banebot wheels) we were only getting about 40'.

Re: Team 67's incredible shooter
 

Might be a strange question, but why only three wheels as opposed to 4, 5,6, etc? Weight, practicality? Was there something that made 3 the "sweet spot"?

Re: Team 67's incredible shooter
 

That's just what we needed to get the distance. I can't say we thought about adding any more than 3.

We did experiment with a wheel on the opposite side of the main shooter wheels, to eliminate curve. But, it didn't do much and kinda got forgotten about.

Re: Team 67's incredible shooter
 

That is an interesting reason to try the wheel on the opposite side... we thought about that for the reason to trade less angular velocity for more linear.


The 3997 screaming chickens have a circular shooter that I believe could have been long range, because man that thing had some serious power at close range, low to ground feed drive, steep angle... when it scored the 3 point... it went in about 45 degrees with no hint of even coming close to leveling out... it slammed into the goal. I personally like this.

Re: Team 67's incredible shooter
 

I think 67's curve really seems to help their FCS ability and I wouldn't make an effort to eliminate it. However, for those of you reading this thread looking to copy 67's shooter but without the curve, I thought I'd share a tip. We built a somewhat similar shooter this year (multiple orange Banebots on a linear shooter, hitting about 40-45 feet with two of them) and had a similar curve to 67 near the end of our trajectory. We found that for us, the best solution was to constrain the frisbee as much as possible in the shooter. While a 2" opening would often result in a frisbee that veered in one direction after about the 25 foot mark, a smaller opening constrained with smooth plastic (especially on the side with the wheels) would always go perfectly straight.

I really admire the 67 robot this year. I think it's a design strategy a lot of teams attempted in various ways, but few could execute so well. I wish we were smart enough to come up with some of their design details in season, but I highly doubt we could have executed like they have.

Re: Team 67's incredible shooter
 

I wonder if that might have had more to do with disc wear than wheel wear? We were seeing some pretty nasty discs by the end of quals at MSC.

Are the game pieces at CMP usually brand new?

Re: Team 67's incredible shooter
 

For a couple of rounds. Then they usually use new ones for elims.

Peyton

Re: Team 67's incredible shooter
 

How constrained did you make it? You said that a 2" opening didn't go straight enough so that you made it a smaller opening. Did you make it as small as 1.5" or closer to 1.75"?

Re: Team 67's incredible shooter
 

I'd have to measure to be sure, but it was pretty close to 1.625. We machined 1/2" delrin stock down, adding a taper to the loading end, and placed it on the top wall of our shooter. One stick close to the wheel side, one stick close to the wall side. The main effect was getting rid of our height variation but the curve disappeared too.

Re: Team 67's incredible shooter
 

Chris, you are correct. We attempted to eliminate it prior to attending any district competitions, but once we figured out where it shot and how well we actually use the curve to our advantage. We pretty much shoot straight for the 2pt goal, and let it arc back to the middle of the 3pt goal.

Your tip is interesting, we can see the track of the disc heading out and atleast on our shooter they want to track out early. We think part of the consistency of this shooter, is that we do not try and constrain the disc at all.

As as the accuracy going way at the end of MSC, we think either the other wheels are wearing down now (losing grip) or the doors they opened up to allow teams not in the elims to clear out of the pits, may have been creating a tiny amount of draft that may have influence the long shots. Who knows?

We will be replacing the shooter wheels at the start of Champs, I'll keep my fingers crossed that it continues to shoot well.

Adam

Re: Team 67's incredible shooter
 

We have verified on our practice field that drafts have a large effect on our shots. Even our up close ones.

Re: Team 67's incredible shooter
 

I was talking to the team this morning about the importance of art hence (STEAM vs. STEM), and immediately thought about team 67's 2012 robot...

I know this is slightly off-topic but since compliments are going towards team 67. I just wanted to add this one in as well... here it is around a little more than a year later and that 2012 robot still sticks in my mind. There is something about it that was a beautiful work of art and so unique. A belayed kudos goes out to you guys... I just wonder how much of artistic influence went into the design.

Re: Team 67's incredible shooter
 

James,

Thanks for the comments. I can't say the robot was designed specifically with art in mind. The most important deisgn criteria is always performance in any of the parts / systems we design. But we do try to abide by the saying -- if it doesn't look good (right), it probably isn't good (right).

So much of the time we continue to iterate our designs until they are as simple as possible, while maintaining functionality.

Any of the other things that we did to help increase the appearance of the machine (vinly on the arms, blacked out cover, *bumpers, etc...) were done after the fact to help with the aesthetics.

*I believe we had 3 sets of bumpers that elevated in appearance throughout the season. Ahh...the things you can do when the robot works well..

Re: Team 67's incredible shooter
 

That is very true and not seen on a lot of robots. Excellent looking bumpers and graphics is a need. It shows the teams brand and shows off the robot's sponsors.

Re: Team 67's incredible shooter
 

Our shooter was very similar to 3997, We did try to see how far we could shoot after Champs and when we ramped it up the wheel was going so fast it just never caught the Frisbee and went less distance then at 40%. It went only 5 feet maybe. Going slower (80%, 90%) didn't really help us very much either.This is why most full court Shooters either use different wheels other than pneumatic or have to wheels one to speed the Frisbee up into the second.
Here is a look at our shooter we never took video of trying to FCS.
http://www.youtube.com/watch?v=WjGaCqWNH9Q

Re: Team 67's incredible shooter
 

1310 usead a andymark pneumatic wheel up too champs then switched to a Mcmaster carr pneumatic like 610.

Re: Team 67's incredible shooter
 

We had the same thing this year. Sleek looking bumpers change the whole feel and look of the robot. Here are a few pics:

Before

After

I should mention that the original bumpers were also illegal, someone came up with the crazy idea to use denim for the blue side

Re: Team 67's incredible shooter
 

"Aesthetics matter: attractive things work better." - Don Norman - Author
Not only do attractive things work better, but our experience has shown that students and mentors alike will work harder on things that look really cool. If you spend a little thought, time, and effort on aesthetics, it will pay back many times over in additional effort by your team.

Re: Team 67's incredible shooter
 

"If it looks good it will fly good (is a myth that is sometimes true)." -John McMasters

In addition what Jim said, in order to look good you've really got to sweat the details. I have found that when you sweat the details, you end up with a much better product. Think about the difference between haphazard holes and precise bolt pattern.

Re: Team 67's incredible shooter
 

I know this is an old thread but I have a couple more questions about team 67's shooter if they don't mind. What angles do you shoot at for autonomous and full court shooting? what do you do to get Frisbees from the bucket into the shooter? Do you happen to have any CAD models or drawings of your shooter?
Thanks in advance if anyone from 67 can help! -Jay

Re: Team 67's incredible shooter
 

I have a few pictures from CMP that will hopefully help you a bit. I didn't get very good documentation of 67's shooter, but it looks like they have an L bracket attached to a chain run that acts as a conveyor and pushes the front of the Frisbee:

https://drive.google.com/folderview?...&usp=sha ring

https://drive.google.com/folderview?...&usp=sha ring

Re: Team 67's incredible shooter
 

Yup it's a short run of chain with an L bracket on it.

You can see one end of the chain in this picture. http://i.imgur.com/UBS1NPG.jpg

Re: Team 67's incredible shooter
 

Jay,

The angle varied at the wheels worn in during the competition. We had to continuously adjust the shot positions throughout the competition to keep up with the changing wheels.

Our nominal pyramid and autonomous shot was around 20-21 degrees. Any time we lost our position of the potentiometer, we would use a digital inclinometer to adjust the autonomous shot back to 20 degrees, then make fine adjustments from there.

For full-court shots, the angle was a little bit lower. This usually changed a lot as the wheels wore in. Theoretically it was setup around 10-12 degrees. Not exactly sure what angle we shot at most of the time. Knowing the exact angle was a little less critical since our operator manually adjusted it during each match to keep the shots hitting in the middle of the goal.

As Akash and Michael pointed out, we used a piece of 1" AL angle riveted to a connecting link (7321K7 @ McMaster) with a platform on it. The chain ran under the hopper and grabbed the frisbee on the inside front lip and pulled it into the shooter wheels. I designed it to release and dip under just as the frisbee was contacting the wheels. We used bike chain and a VEXpro planetary that was geared to 100:1 (if I remember correctly) with a AM9015 motor.

Our drawings and CAD models are so crude, it would be pretty embarassing to show them to anyone. But, I'll see what I can find.

-Adam

Re: Team 67's incredible shooter
 

Thanks for the quick and thorough response!
-Jay

Re: Team 67's incredible shooter
 

I just stumbled across this very informative thread. Adam, have you guys experienced any problems with side loading of the 550 motors? I'm looking to set up some Banebots RS-775 motors in a similar belt drive configuration with the pulley cantilevered on the shaft, but had some doubts about how the motor's internal bearings would hold up over time. (The 775 motor only has a 7.6 mm long shaft, which is another problem in itself...)

Cheers,
Phil

Re: Team 67's incredible shooter
 

No problems to date with any of the motors we used on either the practice bot or the competition bot. We tried to take special care to not over load the motors with excessive tension on the belts.

I would guess that a 775 would be even more robust to a setup similar to ours.

Re: Team 67's incredible shooter
 

That's very interesting to me. I've always seen detailed CAD as the mainstay of every highly competitive team, and I'm interested in how a multiple time Einstien winner can perform extremely well and not do a detailed robot CAD.

For instance, how did you know that your climber could grab levels correctly, that nothing would break under stress, that screws would clear other parts, that there would be enough room for electronics or other mechanisms, or that you'd be under weight? Frankly, I don't think I could design a robot without detailed CAD. Things are so many times different sizes than we think them to be that simply fitting everything together would be a huge challenge, at least for me.

Can you shed a little light on your design process?

Re: Team 67's incredible shooter
 

I would say that a detailed CAD process is the rule to follow, but there are always exceptions. When it comes to our design process, we are not the model that should be emulated. The designs that come from our process...maybe. But, the actual process...no!

We have two main designers, myself and Jim Meyer. Our robot is designed 99% in 2D AutoCAD. I sometimes use Solidwork to model already designed parts, but almost never for the design process itself.

Our 2D drawings are very much like very detailed sketches. Almost all the components are sketched out in an assembly view, but the very fine details are usually put in the print sent to the machine shop, and not in the assembly view. So our CAD files are almost impossible to decifer unless you are the designer currently working in the sketch.

Since we have full access to a water-jet machine, we try to design the majority of our parts to be manufactured that way. Since we only need a 2D file to export to the water-jet, it works out that we do all of our design in AutoCAD.

From a strength or weight analysis, our process is very experience oriented. We are confident in our abilities to estimate how small or large a part needs to be to survive in a FIRST environment. Along the same lines, we try to re-use similar designs for the frame, wheels, etc... so we usually know if a part or assembly is going to put us over for weight.

This style of design relys heavily on the designers to be completely involved in the manufacturing and assembly of the parts. Since they are really the only ones that know exactly how the parts are designed to work together.

As I said above, it's not a process that should be copied by anyone. We have made attempts to streamline the process...or add in aspects of other peoples design process (148, 1114, 254, etc...). But, every time when things start getting tight for time during the build season, the process reverts right back to where it has always been.

At this point, we have pretty much accepted that, like it or not, this is who we are...and how we operate.

The time we have to work on our designs seems to be getting less and less each year (between family and work responsibilities), so we don't do much more than is required to get the parts machined and assembled.

We are in the process of adding some more mechanical/design mentors that hopefully will help improve our process and provide more time to further enhance our designs and be able to teach more students/mentors how we create our parts.

-Adam

Re: Team 67's incredible shooter
 

In a way, this is one of the coolest posts I've read on CD.

I definitely agree that detailed 2D design work can be used to figure out the geometry of a design (I always think back to the 2D drawings of Simbot SS) but doesn't it get difficult to make iterations, even with a practice bot and the district model?

Thanks for the insight!

Re: Team 67's incredible shooter
 

Thank you very much! A very interesting read.

Re: Team 67's incredible shooter
 

Adam,

The digital inclinometer seems really nifty, do you have a part number for this guy?

Thanks!

Re: Team 67's incredible shooter
 

In a pinch most smartphone platforms have inclinometer apps.

Re: Team 67's incredible shooter
 

Yes and no. I usually find it's a lot easier to copy over a bunch of lines in an AutoCAD drawing and cut/trim/modify a current design to a new iteration that I do trying to adjust a solid model or assembly. But, that could be b/c I use AutoCAD a lot more than I do Solidworks. It does take a lot more concentration to make sure all the little details are carried over to new drawing or sketch.

I'll have to stop by the shop and look at the brand we have, but it was very similar in design to this one.

http://www.amazon.com/Digital-Inclin..._sim_sbs_hi_14

If you didn't have one around, I would say a cell phone with an inclinometer app would be just as useful for the level of accuracy we were trying to hold. We just opted for the digital inclinometer b/c the shop had one we could borrow.

-Adam

Re: Team 67's incredible shooter
 

Yep. The trusty "Level" app on my iPhone was THE measurement device used to set our shooter angle. We used the same app on the same phone through our many iterations of shooter to try and get fairly accurate results.

If the shooter was set to the proper angle (27 degrees I think?) we had no issues with scoring.

-Brando

Re: Team 67's incredible shooter
 

You must have quite the level app on your phone. Actually, considering how accurate your bot was, that is really surprising. We used a phone level app to get our shooter dialed in, but it just wasn't accurate enough to get us aligned to the 3 pointer.

Re: Team 67's incredible shooter
 

So this is kind of one of those funny measurement things. Do you really care what the absolute angle of your shooter was? No, probably not. What you cared about was A. the frisbee going into the goal and B. the shooter being in that same spot everytime.

For this, the app on my phone gave a very repeatable result for us. The actual angle it was measuring was probably not extremely accurate, but we didnt care. We knew what number the app spit out that put the discs in the goal. The consistency came from a very heavily iterated shooter design (we built 8 complete shooter systems over the course of the season).

-Brando