Team 95 Hard At Work - 2015
 

Since a number of people enjoyed our thread last year, here it is again for 2015: Team 95, the Grashoppers, fabricating parts!

Thusfar we have a number of chassis side-plates blanked out on our CNC plasma cutter:


Hello little kitty!

A close-up of the various surface finishes we've tried out so far:


I think this is the biggest chunk of metal I've ordered for FRC:

Re: Team 95 Hard At Work - 2015
 

With CAD nearly finalized on most of the robot we have started making chassis and drive parts in earnest. #10AWG aluminum sheet is our material of choice for these parts.

Keeping the plasma cutter busy.

Re: Team 95 Hard At Work - 2015
 

And the Prototrak is kept busy with final machining operations on the plasma-cut blanks.






And the lathe. Here we are using the tail stock to help broach some delrin tubes.

Re: Team 95 Hard At Work - 2015
 

Looking good! We're looking forward to playing with you guys in Nashua.

Looks like a cribbage board had been made on the Prototrak?

Re: Team 95 Hard At Work - 2015
 

Thanks! We are as well.

Bring your cards and pegs, we'll play cribbage on the robot while we wait for eliminations matches! I swear we'll be on the same alliance one of these years... I still regret not picking you guys in 2012 when we had the chance.

The hole patterns are for the chassis style we've adopted - plates and standoffs, like last year's robot. It plays well to our strengths, i.e. plasma cutter and Prototrak and has proved to be elegant and robust.

Re: Team 95 Hard At Work - 2015
 

Grasshoppers are one of the weirder teams in FIRST.
I mean that as a compliment.
Your team inspired my team in 2004.
Winning with a wastebasket in Ultimate Ascent.

I see a whole lotta love in your fabrication pics.

What unique strategy do you have in store this year?

Hope to see you at the NEDCMP.

Re: Team 95 Hard At Work - 2015
 

Thanks! We like getting called weird and unique. :D

I must extend a belated Thank You for the creativity award you gave us a Hartford last season. Your award (more so than the official creativity award) made the event for one of our rookie students - he kept it on his lap for the whole drive back, and only begrudging put it on the shelf in our build space.

Our strategy this year prioritizes getting the recycling cans quickly, giving our alliance partners easy access to them, and scoring the cans on stacks up to 5-6 tall. With a dash of making 2-wide-by-3-tall stacks in there. We figure a typical Ri3D robot can quickly make a stack of 6 totes from two stacks of 3 totes, plus all the landfill totes are laid out in twos...

We hope to see you at NEDCMP as well! We were very close to making it last year, hopefully a little more success this year will get us in!

Re: Team 95 Hard At Work - 2015
 

I'm all for teams picking a set of build methods based off their fabrication strengths... we certainly have picked the way we build based off our available resources! That said, I meant less the spiffy-looking robot parts and more the piece of sacrificial wood on the Prototrak in the first picture... :-)

That said, a few hands of cribbage between matches sounds like a good idea!

GSR 2012 was a bizarre event for us... though I'm in way complaining about the finalist showing. I certainly couldn't criticize anyone above us for not picking us though, as we were anything but an offensive juggernaut at GSR! We were just glad to be able to be able to assemble an alliance that made it to the finals!

Re: Team 95 Hard At Work - 2015
 

Parts are looking great guys.
Who's Austin/Morris Mini is that there in the background?

Re: Team 95 Hard At Work - 2015
 

Thanks!

The Mini is being completely rebuilt by the shop's class (Industrial Mechanics and Welding) and is owned by the shop's instructor. When I say 'completely rebuilt' I mean we have head to clear connecting rods off the work bench to get some space!

Re: Team 95 Hard At Work - 2015
 

Obligatory plasma cutting video of some of our chassis plates.

-0.100/#10awg aluminum sheet
-45A w/ 45A fine-cut consumables on a Hypertherm Powermax 85A power supply
-100ipm travel (table is not stiff enough to go faster, unfortunately) on Norther Plasma table and controllers.

Video here.

Re: Team 95 Hard At Work - 2015
 

Progress!

We finished assembling, greasing, and burning-in most of our transmissions.



We also experimented with Pem Nuts in our continuing effort to use only blind fasteners without tapping any material. Most methods worked well at setting the Pem Nuts, aside from the hammer. Also pictured is one of the 12V Rigid impact drivers that we recently acquired. We really like them and their 12V drill companions.



We also assembled a drive module! 6in AM mecanum wheels direct-driven from a single-speed double-reduction Vex transmission. The shaft is not cantilevered, but supported by a bearing in the outer plate. Free speed is a little higher than I'd like at 14ft/s, but I felt this was a reasonable compromise to use virtually all OTS parts, especially with the ability to throw 4 mini-CIMs into the drive to up the drive's performance. As-pictured it weighs around 18-19lbs.


The drive pod also fits the battery quite nicely, which will serve as a counter-balance for our arm. We will be relying on closed-loop control on the mecanum wheels to account for the inevitable CG variances.

Re: Team 95 Hard At Work - 2015
 

Looks good 95! Glad to see you guys doing this thread again this year it was enjoyable to see your robot progress through the season and then iterated at events!

Re: Team 95 Hard At Work - 2015
 

Thanks Brendan!

Re: Team 95 Hard At Work - 2015
 

We had a very productive Saturday.

We kept the plasma cutter quite busy making all sorts of parts.

0.032 sheet metal can warp a bit when being cut, it's amazing watching the automatic torch height controller track the material as it lifts and settles.



They lay reasonably flat after some sanding and deburring to remove dross.



We also blanked some parts out of 3/8in 6061T6 at 45ipm.



We also made a number of small steel parts and popped some steel rivnuts in them. These will be the bases for some magnetic latches.

Re: Team 95 Hard At Work - 2015
 

Assembly progressed reasonably well with the robot's chassis.

An inside view of one of the drive pods. I was pleased to learn that a 10-32 Riv-Nut flange does a good job of locating the 7/16 hex sockets in a Vex transmission.



You can almost see the outboard bearing in this picture.



Arm pivot posts and fixed sprockets were installed.



Again, liberal use of Riv-Nuts, though they are difficult to installed near their maximum rated material thickness.



And at least one of the arm shoulder motors was installed.

Re: Team 95 Hard At Work - 2015
 

A number of other parts were made and/or futzed with.

Re: Team 95 Hard At Work - 2015
 

Some of that aluminum looks really thick for a game with no defense. :P
And what kind of arm are you running?

Looks great so far, guys. Keep up the good work!

Re: Team 95 Hard At Work - 2015
 

The main chassis plates are #10awg sheet metal, 0.100in. It is probably a little overkill for this year, but on the other hand we get the material for free and we were able to remove a lot of it for lightening, "trussing it out" as we say. Other 'major' parts, like the belly-pan and deck, are being made noticeably lighter than last year.

We've designed a 4-bar linkage arm with a little more than 180deg of total travel. It will be counter-balanced by two air cylinders and drive by two CIMs + 50:1 Versa planetaries + 16:60 sprocket reduciton.

Also, some over-all chassis pictures finally got uploaded. Around 47lbs as she sits currently.

Re: Team 95 Hard At Work - 2015
 

We've been keeping the mills busy:



And throwing our fair share of money at VexPro:



So many prototypes....

Re: Team 95 Hard At Work - 2015
 

The chassis is coming together though!



And so are some other assemblies.

Re: Team 95 Hard At Work - 2015
 

Wow love you design of your base and that great shop too. Good Job.

Re: Team 95 Hard At Work - 2015
 

Thanks! :)

Re: Team 95 Hard At Work - 2015
 

I love this thread and your designs. Just curious, why a cim and mini cim per wheel? On your hinged mechanism, how did you get that bend in the back off the pivot???
-Ronnie

EDIT: After looking further, It looks like you might of cut that piece that curves around the axel.. I thought it was all one which made my jaw drop.

Re: Team 95 Hard At Work - 2015
 

Thanks! We appreciate the kind words!

We figured more power, better drivetrain! I think the CIM+miniCIM might wind up being a little overkill, but I'd rather be stripping weight out then adding it in later, so we planned optimistically for an 8-motor drive.

The gripper mechanism is just a piece of #10awg 5xxx al sheet bent into a c-channel with an OTS hinge from mcmaster bolted to it with some drilled holes and PEM nuts.

Re: Team 95 Hard At Work - 2015
 

Lookin' very sweet; can't wait to see the finished product! Wish I was available Week Zero... :-/

Re: Team 95 Hard At Work - 2015
 

Thanks, me neither! We're off to Suffield Shakedown and not Chop-Shop's Week 0, it filled up too fast.

Re: Team 95 Hard At Work - 2015
 

That's a hike. Sadly we aren't going to either. We never got a notification Week 0 registration was opening.

Not sure what we'll do that weekend but it might be useful to us if we aren't spending 3-4 days getting ourselves ready for a competition but continue focusing on the robot for the first event.

Re: Team 95 Hard At Work - 2015
 

Getting there...

Re: Team 95 Hard At Work - 2015
 

I love the idea of doing this post. It's amazing to see how much you guys progress over the season! Great job, Keep it up!!!

Re: Team 95 Hard At Work - 2015
 

I like the manipulator. Seems like it would be really effective at both totes and containers.

Re: Team 95 Hard At Work - 2015
 

Thanks! I/we was/were getting tired of all of the teaser pics and opted for some transparency instead. If another team wants to copy any we put up, please do!

Thank you!

I can't wait until we have good pictures of the real tote manipulating mechanism(s). But that's all in CAD for now, prototypes were just wrapped up this week.

Re: Team 95 Hard At Work - 2015
 

Had a lot of progress over the weekend. Here are some of the pictures.

This is our main assembly area. Note the house-wiring practice area to the right, this is for the day-time class that uses this space.



What the CAD of the gripper looks like:



The arm assembly is getting some tweaks to improve stiffness.



Decided to try out velcro to mount electronics this year. It seemed like a good opportunity given the lack of defensive impacts we'll see.



And much of the robot got wired up! We made all the transmissions turn and such. No pneumatics and no real sensors wired... yet. We left PWM and other signal cables loose to aid in debugging.

Re: Team 95 Hard At Work - 2015
 

Cool, did you use a bead roller on the belly pan? Does it add any noticeable stiffness?

Re: Team 95 Hard At Work - 2015
 

Yes we did and yes it does, it makes a very big difference in stiffness, at least qualitatively. It was the first part we ever bead-rolled (and my first, personally). Was a little nerve-wracking for the student and I who did it, but it's pretty easy to do, would highly recommend to teams who do sheet metal parts.

We also noticed that the bead makes a good shape to drop counter-sunk bolt heads into... but given that we're using Velcro this year we haven't drilled any holes in it yet.

Re: Team 95 Hard At Work - 2015
 

Looking good.

Re: Team 95 Hard At Work - 2015
 

The deck is PET-G, not polycarbonate. We have found PET-G to be nearly as robust as polycarbonate while being roughly half the cost. The deck was cut on my CNC router.



Another view of the chassis.



Some big steps were made in assembly of our main arm.

Picture of the 4-bar links.



4-Bar being moved by hand to show the arms articulation and range.

https://www.youtube.com/watch?v=ahGZ...ature=youtu.be

As she sits we're looking at 75lbs for the base and 10lbs for the arm+gripper. Not too bad...

Re: Team 95 Hard At Work - 2015
 

Interesting video. Your arm is positioned perpendicular to your wheels and appears to go on both sides of the robot.
Can you talk about those design decisions? It looks to me like it was done such that step-container autos would be easier, but I'm not sure.

Re: Team 95 Hard At Work - 2015
 

I can, and am happy to.

The primary objective of this arm mechanism, our main mechanism, is to grab RCs off of the step and place them upright on, or near, the scoring platform for us to use later, for our alliance partners to use, and to deny them from our opponents. After doing a time-study we concluded that being able to do grab and place the RCs without any significant driving or robot re-positioning (i.e. grab, back up, turn, place, drive to next RC, realign, grab) was the most effective method. Currently our operation looks like: align, grab, drop behind, drive to next, grab.

After looking at the geometry we determined that the same arm that could grab RCs from the step could also cap 5-6 tote stacks on the 'front' and at least 4-tote stacks on the 'rear.' Given the ability to rapidly deploy a single arm, with a single degree of freedom, we thought that this would make a great counter to any robot that makes a grab for multiple RCs in auto. Could that robot hold onto 2-4 RCs if we're latched firmly onto one of them, pulling with all of our might?

The arm is designed to reach the RCs on the step without disturbing any of the totes in the landfill. We wanted to reduce the destabilizing moment from the RC and improve the stabilizing moment from the robot to make our RC-grabbing design as capable and fast as possible. This dictated pushing our wheelbase as close to the RC as possible. Orienting the wheels as we have does this. A traditional tank drive would require a lot of coordination and/or very precise driving in order to align on a recycling container. Mecanum wheels, on the other hand, allow us to drive 'forward' onto the RCs, as well as 'strafe,' to reduce the difficulty in acquiring the RCs while allowing us to put wheels where we wanted. This, coupled with the fact that we've made a mecanum robot before, lead us to select mecanum drive over alternatives like h-drive.

Re: Team 95 Hard At Work - 2015
 

Well done. I look forward to seeing it in action!

Re: Team 95 Hard At Work - 2015
 

Do you plan on using sensors to position or are you just going manual on that?

Re: Team 95 Hard At Work - 2015
 

Encoder plus a magnetic limit switch or two.

Re: Team 95 Hard At Work - 2015
 

"Virtual" 4 bars are my absolute favourite mechanism to see on any robot, and I'm very impressed with your implementation. I love the idea of aircraft cable (or something similar) for the parts of the 4 bar where you don't need chain. Nice work.

Re: Team 95 Hard At Work - 2015
 

Thanks! We like using chain for 4-bars, but the arm is so long that the weight was really adding up. Enter the 221 robotics tensioners, some 3/32 cable, and a few custom clamps anyone can make on a drill press, and voila! Light-weight 4-bar linkage!

Re: Team 95 Hard At Work - 2015
 

Thanks!

We drove it around a bit last night, but the arm damaged the chassis due to assembly with some under-sized screws.

In good news the two CIM motors can hold arm position at about 10% throttle without the air cylinder counter-balance, so it should be quite robust once the transmission mounting hardware is sorted out. On the other hand there are some tremendous forces involved... hopefully we can keep the destruction from happening again.

I hope to have a video of the RC arm in action this week.

Re: Team 95 Hard At Work - 2015
 

Some more parts from the Prototrak. We neglected to take many pictures this weekend.. I promise more soon!

Re: Team 95 Hard At Work - 2015
 

lol

Re: Team 95 Hard At Work - 2015
 

The main arm is ostensibly together and operating.











It runs really smoothly and quietly. The air cylinders do a great job counter-balancing the arm. It needs no motor input to hold position without an RC, with the RC it needs a slight input to hold position, but nothing that two CIMs aren't up to the task of doing. So far it seems that the base is quite stable with the arm moving, like math said it would be. Tonight we'll be driving around with the arm out, that should be interesting. Hopefully some video will get uploaded soon!

Re: Team 95 Hard At Work - 2015
 

Cool stuff! Some questions:

• Looks like pneumatic cylinders are being used to offset the weight of the arm, and you switch them from push to pull depending on what side of the robot the arm is on? Clever. (Edit: doh, nevermind, I see you already described it, and should always pull the same way)
• Are those black brackets you use to connect the chain and cable ends off the shelf parts or fabbed?
• What's the mystery material you have lining the edge of your gripper, and how well does it grip? We're still in the hunt for a good material.
• What's with that big metal truncated icosahedron in the background?

Thanks for posting your build, it's fun to follow.

Re: Team 95 Hard At Work - 2015
 

Correct, the cylinders always 'pull' and thus need no controls. They also provide some nice damping in the arm system and act as the hard-stops.

The chain tensioners are OTS from Team 221: http://www.team221.com/ Nice product, nice interaction with their salespeople too.

The mystery material is from McMaster, it's a rubber edging material: http://www.mcmaster.com/#8507k72/=vv663c It has been working "okay" but not spectacularly. We have another style from McMaster to try that has foam gasket on it and some 3M grip tape, similar to what's in the KOP, that 1519 recommended to us that we're going to test.

The aluminum soccer ball, bolted into the mouth of a 3ft tall steel velociraptor, were two plasma-cutting and welding projects for the class we share the shop space with: Industrial Mechanics and Welding.

Glad you like the thread!

How long is the arm from center of pivot (looks like it pivots over top of chassis) to end of grabber?

Re: Team 95 Hard At Work - 2015
 

On the order of 70in when it is horizontal. It can reach past the center-line of the RCs on the step without disturbing any totes in the landfill.

So you guys must be right at the limit on the 78" height restriction then.

Very cool concept!! Can't wait to see some video of it operating !

Re: Team 95 Hard At Work - 2015
 

Indeed! We are at about 77in at the moment, dictated by pneumatic tubing. About 76in for the tallest bit of metal.

Here is a video from a few days ago of the initial completed arm testing.

https://www.youtube.com/watch?v=vSCOoGvhOaY

The grippers did not actuate because the 12v/24v jumper was not set properly on the PCM.

I hate when the jumper is in the wrong position !!! Makes it harder to blame on Programing lol

Re: Team 95 Hard At Work - 2015
 

Is that #25 or #35 chain on the arm? Very similar concept to part of our robot. What's your thoughts about container tug of wars?

Re: Team 95 Hard At Work - 2015
 

#25

I think that container tug-of-wars will only occur at very high-level of play and may result in one, or both, of the robots suffering damage, and will likely result in more than one up-turned RC.

Re: Team 95 Hard At Work - 2015
 

We changed out our 6in wheels for 4in wheels. We decided that the improvement in fine control and current consumption was worth not being able to drive over the bump. Our geared free speed dropped from the 14-15ft/s range to the ~10ft/s range. Control is improved and we got a little more clearance on the 78in height restriction.

Re: Team 95 Hard At Work - 2015
 

Sounds good! IMO, pretty much anything over 10fps is overkill this year. Will you still be able to drive over the scoring platform if needed?

I think we have an adjusted speed of something like 7fps on our 6" mecanums... I don't think we've actually measured it yet, but it seems about perfect for our strategy (so far!).

Re: Team 95 Hard At Work - 2015
 

Crossing might be iffy at best. We're planning on staying 'far field' for the whole match, i.e. never coming to the human player station side of things. The possible exception being immediately after auto, where we may want to grab cans/totes in auto. In that case we'll just drive around them.

Re: Team 95 Hard At Work - 2015
 

Work continues. Due to poor weather we were unable to attend the week zero event in Suffield CT. We did, however, manage to get a lot of work done and some drive practice in at our work space, so it wasn't a total loss.



Assembly of one of the lifting bars. Each 'finger' is spring loaded on a rubber band and has two degrees of freedom allowing them to conform to the underside of the tote lips.



http://youtu.be/r_sZlhgY5q0

Drive practice with the arm! The tote stacker hasn't been installed yet. Between the weight balance being off, a very uneven floor and some frame quirks the mechanum drive has been less then perfect. Frustrating but all getting worked out.

The end of build is nigh!

Re: Team 95 Hard At Work - 2015
 

This looks awesome!

Re: Team 95 Hard At Work - 2015
 

Update!



The Totem (HA!) is nearly installed and functioning. We've had a very busy last few days.

Re: Team 95 Hard At Work - 2015
 

Well, I am quite pleased to report that our hard work has paid off! :D

1519 Mechanical Mayhem was seeded first at GSDE and selected us as their first pick and 1307 as their second pick. With a careful and somewhat conservative strategy our alliance ranked 1st through all of the elimination rounds! Both 1519 and 1307 were a pleasure to work with and we hope to do so again in the future.

Our alliance and drive teams, plus a bunch of 1519.



We also won the Delphi Engineering Excellence Award for the first time in our history, making 2015 GSDE the most successful event for The Grasshoppers ever.

We would like to thank all of our competitors at GSDE, especially the alliance of 138, 190, and 811 (IIRC) that gave us great competition in the final rounds. 138 - we are working on some improvements specifically to counter RC grabbers like yours! Very impressive.

I would also like to give a shout-out to Jim and Jon of 885, Jeff of 58, and Brendan of 3467, it's always nice to see familiar faces helping to run events and your positive words are much appreciated.

We have a number of improvements planned for our robot before Pine Tree, I hope to have some pictures and/or video of said improvements this weekend after we have a chance to implement them.

Re: Team 95 Hard At Work - 2015
 

Fantastic work this weekend 95! It was mesmerizing watching your robot move seamlessly around the field scoring cans with that elegant arm. The Engineering Excellence award was well earned as that is a beautiful machine and performs well on the field.

Re: Team 95 Hard At Work - 2015
 

Hehe, this was the year! :)

Thanks for sharing. It's always cool to see another team's design and manufacturing process, especially on a machine as nicely built as yours.

Re: Team 95 Hard At Work - 2015
 

Thanks Brendan! Your comments are much appreciated.

Indeed! 1519 and 1307 were both great teams to work with.

You are welcome, and thank you for the compliment. I hope to have even further updates to this thread in the next few days. Always something else to improve...

Re: Team 95 Hard At Work - 2015
 

Some CAD for two of the improvements we will be working on.

Dual RC grabbing from the barrier.


Adding a 'wrist' degree of freedom to aid in picking up tipped RCs. The current gripped can do it, but not that well. This modification should help immensely.

Re: Team 95 Hard At Work - 2015
 

Very sweet! Especially love that 'wrist' on the virtual-4-bar!

Re: Team 95 Hard At Work - 2015
 

As if this wasn't one of our busiest seasons already, we have registered for an additional district event - Week 5 at Hartford! We've always like the Hartford event for it's proximity, great teams, and good venues and look forward to returning and playing with all of the CT teams (it looks like we'll be one of 3 robots from out-of-state, and the only ones from NH).

We are looking at making further improvements to our tote harvesting mechanism in the form of a more robust lifting mechanism and sensor integration to help us align onto the totes.

Edit: almost forgot to update!

The wrist mechanism worked out really well at Pine Tree. The antennae... not so much. They added too much weight to our arm and significantly degraded our RC handling ability, plus they were not very effective at grabbier barrier cans!

Re: Team 95 Hard At Work - 2015
 

First thing we found when unbagging this weekend was that a lot of moisture had worked its way into the robot bag and rusted a number of bearings and pins. Here is some of the (cleaned up) aftermath. WD40, oil, and a wire brush worked pretty well.



We made some plastic spacers to replace stacks of washers on our 'totem' bars. Saved a little weight and they look a little better.



Finished some new 'wrist drive' plates and installed them. These ones are more concentric than our first set, which had lead to some funny arm behavior.



I welded some parts out of titanium wire/rod. These parts will be used in the 'totem' to connect to top bar to the lower three bars. In theory this will allow us to pick up a stack of totes 4 high and two wide.



Finally, we installed and tested a 'sensor array' on the lower-most totem bar that will help us align onto a pair of totes. In the little bit of testing that we did they worked most of the time. We have some fine-tuning to do at Hartford this weekend, but I am optimistic.



Here is some context on the whole robot: http://i.imgur.com/iIfnmXb.jpg

I would be willing to bet that the reason for the rust wasn't moisture working into the bag. More likely from being bagged in a warm environment then being put into a cooler environment causing the air in the bag to condense a bit. Doesn't take long for rust to start that is for sure.
Good luck to you guys today, and we will see you there!

Re: Team 95 Hard At Work - 2015
 

It was nice to meet you yesterday!

I've got a few reasons why I think moisture intrusion might have been the case:

First, it wasn't as if a few components just rusted, there was a concerning amount of condensed water inside the bag that did not evaporate when the bagged robot was warmed up again. This implies that extra moisture was inside the bag.

Second, we have bagged in warm environments numerous times, passed through a cooling cycle, and never saw any moisture condense inside the robot bags before, let alone seen rusted components.

Third, and most importantly, the bag had several small holes it in from being transported in the back of a truck. The robot was loaded into a truck while it was raining outside, and then driven for four hours (mostly covered in a tarp) while it was raining/snowing outside. This provided ample opportunity for moisture to get into the bag. It is possible, if not likely, that the cooling of the robot/bag drew moisture and cold air into the bag though.

Fortunately we now have a trailer to transport everything with, so hopefully this occurrence will be a one-time fluke.

Re: Team 95 Hard At Work - 2015
 

It would be fun to bag the robot with giant packets of silica gel. You could even weigh the packets before and after to see how much moisture is adsorbed-- for science!

Re: Team 95 Hard At Work - 2015
 

From what I saw this weekend 95 had another solid showing at Hartford. I really liked the 6 tote grab out of the landfill!

Re: Team 95 Hard At Work - 2015
 

Thank you very much! I was pleased with our alliance making it to semi-finals at such a competitive event, thank you 3146 and 173!

The 6x tote pull is a subset of what we've been working on. In theory, though we have yet to execute on the field, (read: take this with a huge grain of salt) we could collect 8-10 totes from the landfill and make two 4-high stacks, a 4-high and a 5-high stack, or (very optimistically) two 5-high stacks. Unfortunately this mechanism is very much secondary to our RC arm and thus is less robust, many things have to work out well to mine this many totes. The best we've done thus far is to pull a 4-stack and a 2-stack and cap both. Still, I consider this is a big step up from our 2x2 mining from GSDE. We're now right at 119.8-120.0lbs, which makes it quite difficult to add any more functionality to the totem! All we can do now is practice and refine code.

Speaking of code and practice, a big thank you to 1519 for helping us with, and inspiring us to implement, an IR sensor array that has been key in making our robot more effective at RC mining. We spent much of our time at Hartford refining the control code for this and practicing using it. Here is a picture of the array installed on our lower-most totem bar. These four sensors allow the robot to automatically square itself to, and center upon, two totes end-on. It has worked well in tele-op, but not as well in auto, yet.



We moved the air cylinders for our 'antennae' to be base of the arm and connect them via fiberglass push-pull rods to the antennae. This moved enough mass down off of the arm to dramatically improve arm performance with the antennae mounted. We also added a small plastic 'wheelie bar' on the front of the robot that lets us pull wheelies routinely when lifting RCs.

Antennae cylinder mounted on the arm shoulder:



Overview shot of the push-rod actuated antennae. The fiberglass push-pull rod is red, the carbon fiber antennae is black.



The geometry for these work, and we've tested it in teleop. We just need a slightly more robust auto code to align properly to grab two RCs in auto. Currently we're brainstorming ways to make this happen.

Re: Team 95 Hard At Work - 2015
 

I forgot to mention the on snafu we had with the IR sensors: the plastic house on them is designed to be shielding, and thus it is conductive. We had to isolate the housings with some VHB from the KOP and then passed inspection. That was a weird issue I had never seen before!

Re: Team 95 Hard At Work - 2015
 

Isn't VHB tape magical?

Re: Team 95 Hard At Work - 2015
 

Glad to keep seeing you guys improving and iterating; we look forward to playing with you guys again at DCMP!

Sorry... forgot to warn about that!

Re: Team 95 Hard At Work - 2015
 

It really is! Though we need to stock up on some rubbing alcohol for our pit. Gotta clean off everything really well for VHB to work to its potential.

We also used VHB and zip-ties to terminate one end of the push-rods on our antennae!

As are we! There isn't another stacker quite like 1519, and no other team (so far) has been able to keep us busy with just capping.

And no worries. It took a little while to fix, but it was a good object lesson to our whole team to not make assumptions! Plastic with carbon is quite conductive.

Re: Team 95 Hard At Work - 2015
 

What happened? I noticed that the division scouting spreadhseet (https://docs.google.com/spreadsheets...hC0/edit#gid=0) had you in Carson, and I got excited, but you weren't on TBA or FIRST's website as attending championships.
I then checked here: (http://frc-districtrankings.usfirst.org/NE), and it seems to say you declined the championship invite!

I was disappointed to hear you weren't coming to champs (and couldn't be a total steal in the 4th round as a capper on an awesome alliance :D).

Re: Team 95 Hard At Work - 2015
 

Lack of money and time happened, unfortunately. :(

Our team is about 13 students, 5 technical mentors, and 4-6 non-technical mentors. None of the three on our programming crew could make St. Louis, I and 3 other technical mentors were out of vacation time, none of the non-technical mentors could make it, and we didn't have the money reserves to put up $5k right away.

We saw this coming several weeks ago, but we had a hard time scraping together registration for District Champs and had no gas in the tank left over to get the $15k we needed for a trip to Worlds! We have lost a significant portion (around 40-50%) of our sponsorship backing since our 2013 season; we're still feeling the sting of the 2013 federal budget sequestration crisis. We are continuing to work hard to expand our sponsor base, but it does take time to develop good sponsor relationships and to recover what we lost.

We hope to make it to worlds again in the next year or two, but it just was not in the cards this year unfortunately.