TEAM2980 Open Source Robot Thread

[asid61]

Originally Posted by eedoga

So...a couple of things in response to questions that have been brought up about our team and robot.

Our design process is a bit abnormal...

Right after kick off we divide up into four separate teams. Each team designs a robot using a worksheet that our team uses.

https://docs.google.com/document/d/1...it?usp=sharing

Each team then does a CADD mock up using autodesk inventor during week 1. On Friday night we invite the community. This year we had over 100 people show up for this event.

Each team presents their idea in a 10 minute presentation, and then the entire team leaves the room.

The community including some graduated team members then argue about which design the team should build. This year they chose two different designs and combined them. (We will post the video of this soon...We are waiting for our Video Productions class to finish editing it down.)

We then spend week 2 doing a final CADD of the entire robot. We also use some of this time to prototype things to see what works.

Then we get to work actually building a robot. Week 3 is for Fabrication, and week 4 is for final assembly. We are pretty well on schedule at this point having finished welding our base frame today, and cutting out most of the parts for both lifting mechanisms.

So...This years robot.

We are using 1 lift mechanism to try to do a 3 tote autonomous stack. The plan is to pick up 2 of the totes, and then push the third into position dropping the two we lifted down on top of it. We are planning 3 seconds per tote with a few seconds in between which we understand is ambitious.

We then have a multi-purpose lift mechanism which we plan to use for totes and recycle bins.

We are using a halonomic(sp?) drive base.

Earlier in the thread we linked to a Github which has all of our CADD files posted in it. We have also posted renders of our robot. We will post more in the next few days.

Currently our base is driving around. we will be adding to it tomorrow...

We will post more at the end of the day.

best of luck to all teams.

Edoga

That's holonomic BTW.
By "the community" do you mean FRC people or parents/ kids etc? Becuase every year we do get input from parents and such during design reviews, but many ideas suggested show a sever lack of experience doing this sort of mechanical stuff (we have plenty of electrical engineers, though).
It looks pretty sweet either way though, and pretty bulletproof. Your elevator is a little less strong that it could be IMO, but I really don't know if you will have any issues. We are using bearings on three sides of the walls of our elevator.
3 seconds/ tote might be tricky if you can't position the arm quickly. One side of your robot needs to pull a stack into it, and the other side needs to laign the tote properly. Either of these tasks can be difficult.

[josephus]

Originally Posted by asid61

By "the community" do you mean FRC people or parents/ kids etc? Because every year we do get input from parents and such during design reviews, but many ideas suggested show a sever lack of experience doing this sort of mechanical stuff (we have plenty of electrical engineers, though).

By "the community" we mean the community. That is, we send out invitations to public officials and specific people or organizations whom we want to come, and we publicize the event widely with an open invitation to anyone who wants to show up. We usually get parents, old engineers, representatives from local sponsors, old team members, naval technicians from our local naval base, possibly state legislatures, other public officials, and people from the general community. Experience combines with common sense in the discussion after the presentations, and there is a Q/A session immediately after the presentations that allows for dynamic input from the design groups.
Our first two years, we decided on robot design without the community and great ideas were passed over by either the mentors lack of faith in the design of the students (which appeared in many robots at competition) or the popularity of the people on one of the design groups. Presenting to the community allows for widespread discussion as well as removal from team biases. It is also a great way to involve the community with FIRST

[eedoga]

This weekend was really good for us. We had some real successes and are hopefully back on schedule. I was feeling like things were going too slowly and that too much was up in the air.

Going into this weekend it felt as though we hadn't accomplished anything real. Things were also going really slowly. So cutting out parts seemed to take forever...We would have a meeting and three parts would be made at the end with 1 of them cut out wrong and needing to be redone...Our welding mentor got stuck doing paperwork so we thought we might have to build the robot using rivets and brackets...So we furiously began cutting out brackets and bought out all the rivets the nearest harbor freight had in stock...

So...This weekend...

We drove...Just the base and electronics board, but we drove around using our holonomic drive train.

We got our base frame welded.

We got our battery moving mechanism mounted.

We built the frame of our rear lift mechanism.

We built our front gripper claw frame and mounted the dart linear actuator. (still needs a bit of work, mostly figuring out the bolt needed to connect the bracket we made to the end of it.

We decided things, like using square tube for our gripper rails instead of 80/20, and making an electronics cover using 1/16th polycarb...

We also got in some parts that our material sponsor, Bowman Manufacturing, laser cut for us. (they came in at 7 PM tonight.)

We welded up the practice frame.

Really this next week we can focus on finalizing fabrication and initial assembly, then the Guild, the art club on campus can have at it to make it pretty. :-) (The community stressed that they wanted little artistic flourishes throughout the robot.)

Did I mention that we learned how to anodize!? :-)

What a weekend. The really cool thing is that there is no school on Thursday because we are changing over semesters, so the team gets the whole day to work, though we may break early tomorrow so that people have time to study for their finals.

Honestly though I am feeling much better now than I did even on Friday.

Great work everyone!

Edoga

[asid61]

Wow, that's a lot of stuff! You guys are super industrious.
How are you anodizing?

[eedoga]

I am going to have the team member who figured it out post a tutorial video by tomorrow showing how to do this. I have him in my robotics class and I think this would be a good activity for him. :-)

Edoga

[eedoga]

Shot a video of our front lift mechanism today..

https://www.youtube.com/watch?v=CicuLpABr54

This was testing with the lifter at about 90 degrees. We plan on tilting it back in the future. we are using a 30:1 shifting gear box that we originally got last year to use for winching our shooter...

[eedoga]

At long last...Robot is bagged and tagged, and here is the reveal video.

https://www.youtube.com/watch?v=YR-3FkKNsz0

Now sleeps. :-)

[eedoga]

Been a few weeks...I've had some time to think about our robot, and to see what other teams have come up with. Now that all is said and done we need to think about how our robot can fit into a larger strategy or alliance, and also to not necessarily compare ourselves to some of the other teams that all teams want to grow to be...So teams like 118, and 148 for example. Of course they have amazing robots. (Well...not of course, I am sure they work darn hard to get to where they are and I am not trying to diminish that in the least...) More they have a track record of amazing robots. Here at team 2980 we have to maintain perspective and work with what we have...

So...The bad? (I would start out with the good, but I want to address each of these things in turn to show how I hope we as a team can deal with them...)

Our robot isn't very fast at loading from the feeder station. This in fact was something that we saw, and in a way may have overlooked...Nami, one of our designs was an internal bottom stacker which would have been perfect for deeding from the human player station, but the community somehow overlooked this design. There was discussion against using pneumatics, and perhaps we could have used something like a dart actuator or cables to make Nami work... So, depending on our alliance, we can ether follow our plan of working the landfill, or adapt our plan in order to take advantage of the feeder station... The feeder station would probably be the fastest way to build stacks, but, it is also not really what we are designed to do, and if there are any better human player stackers in our alliance then we would want them to be there stacking.

The tradeoff of having a very versatile gripper...In fact we have two lift mechanisms. One of them is primarily for use during autonomous, and would work best for that purpose (specifically designed to lift 2 totes from the side.) The other, the front lift mechanism is incredibly versatile. It can lift totes from almost any angle as well as bins that are upright and tipped over. Here though again, the mechanism is relatively slow when compared to some other robots with active intakes that seem to just eat totes. We are addressing this through modifying the gripper to make it more able to handle several totes at a time aligning them for stacking. We will see how well this works during our access period. We also had a mini cim let the white smoke out during a practice...We have modified the code to make this less likely to happen, but it is still a concern.

Finally our drivetrain... This is probably the most problematic part of our robot, and may in fact work out to be a strength...We went with a holonomicn X drive... This has been a beast to get driving well, and the shifting balance of carrying more than a couple totes is really problematic. We can address this by tilting the stack, which for stacks of two or three is fine, but much after that becomes a tipping hazard. The robot has fallen over a couple times usually when carrying a larger stack and moving too quickly. Here we will have to take full advantage of our access periods and district events to nail down driving in a meaningful way. We have had success dealing with noodles, but that may be more a factor of the slippery floors in our workshop. Hopefully though the angle of the wheels makes them "want" to push noodles out of the way instead of getting stuck on them.

So for the good...

Honestly all of the "bad" things described above don't include the worst thing, which would be unreliability. We have a direct drive, drivetrain which will help to lessen the chances of major drivetrain problems...In that sense we seem to have a pretty reliable robot. Of course we will see at competition how well we hold it together, and perhaps our choice of framing material might come back to bite us in the butt down the road. (we went with 1/16th wall square tube for most of the robot.) In reality because we managed to stay on schedule this year the robot has seen a fair bit of action already. Hopefully things will hold up and we will be able to see any problems before the robot gets out on the field.

I think we will have a great shot if we stick to what we designed for, which is working the landfill... There we should excel, especially if we work out our double lift and stacking idea. In the least we should be able to quickly line up totes for stacking. We will have to work out the best way in which to do this during our access period, and during our district competitions. In a perfect world we would be able to put up a 20 point auto + 6 more if our alliance partners can move into the autozone, 16 tote points, 16 container points, 6 - 10 noodle points, and 40 cooperatition points...that would of course be in a perfect world, and also depends a great deal on the other robots in our alliance. I can see us growing into something like this if given the chance, but really that would all be a best case scenario. I can equally see us putting up something like 20 - 30 points in caps and stacks and failing to get either the autonomous points and cooperatition... Honestly hitting over 70 points in a match would be pretty darn incredible.

The best alliance for us.

would be two feeder station stackers, or a combination of a feeder station stacker and an auto container grabber. We would play cleanup and work the land fill.


We'll keep you posted on how things actually turn out.

Best of luck to all teams!

Edoga