Team 2980's Open Source FIRST BOT
 

Team 2980 has decided to go completely open source. We will be posting everything about our robot, how its put together, how it works out...Everything. We don't mean for this to spoil creativity, more because we have gotten so much from the users of this forum and we feel it is our responsibility to start contributing. So here goes.


This is a back view of our robot. The base is 27" wide, 37" long, and 8" inches tall. The wheels are Mecanum and will be driven by 4 CIM motors. The arm will be driven by window washer motors.

Here is how we are mounting our Denso windshield washer motors

The minibot will be mounted on the platform on the back, and will be deployed using a 20" piston. We are planning on mounting the platform on a turn table so that if it isn't lined up right the cavity in the platform will help orient the minibot.

We only have a flat view of our gripper, but that will be mounted upside down on the arm. The idea is that the arm will flip around to the front. A camera will be mounted on the arm.

STP files are available upon request. We would love feedback on the design. and will keep this thread up to date as we make progress.

Thanks.

Edoga 2980

Re: Team 2980's Open Source FIRST BOT
 

I would love to give you feedback, but your pictures aren't loading for me :(

Re: Team 2980's Open Source FIRST BOT
 

I like the window motor to sprocket mount. We might use that at some point.

What are some stats of your robot? How fast is it going to go? (what are the gearboxes and gear ratio?)

How high is it going to be able to reach?

Keep updating I love the idea of giving away designs to other teams, it just makes sense.

Re: Team 2980's Open Source FIRST BOT
 

So our current design uses 4 wheel mecanum drive. We have the tough boxes set up in the standard gear ratio of 12.75 to 1. We are using 6 inch wheels....Not sure how fast it will go...We have only used 8 inch sticky wheels in the past, or the slippery wheels we used for lunacy.

The arm in its current design has a maximum reach of 8' 8" not including the gripper which adds a few inches. We are hoping to squeeze a few more inches out of the sliding mechanism and to make the arm a few inches longer, but we were not originally planning to go for the top row. (last year we tried to do everything and ended up doing nothing much.) We would love to do more, but we currently only have access to a band saw, drill press, welder, and angle grinder. :-)


This is the tower that our arm sits on. it is 1 inch aluminum that we are drilling 1/2 inch holes in.


This is the arm, we are using a 60 tooth sprocket to turn it. We figured out a way to use the key shaft to couple the sprocket to the arm so we won't be using the set screws as depicted in the model. We should have updated pics by the end of the weekend. We are using the slides to extend the arm. We had to cut 4 inches off of the ends of a 3rd slide to give us 28 inches of travel.

Here is an exploded view.

This is how we are mounting our jaguars. We are doing this so that each motor is a unit


Thanks,

Edoga 2980

Re: Team 2980's Open Source FIRST BOT
 

So we are hoping to get our robot running by the end of the day tomorrow. It really depends on how well we can pull together. Putting in 2 weekend days every week has been amazing, and has made the whole process a lot less stressful...though tiring.



Here is what we have...pretty much...so far. I think we added a bit more with the pneumatics system after this picture was taken. We have the electronics roughed in, and we are starting to rough in the pneumatics. I realized we have a frame perimeter violation that we need to fix tomorrow. One of the linear bearings for deploying the "baby bot" sticks out past the frame barrier so we have to shift that over by an inch to make sure we don't violate any rules.
If you look carefully you can see it closest to the camera...Probably should have caught that in the CAD model. We should have a rough idea as to how much this thing weighs tomorrow. It feels heafty, but hopefully not too heavy.

Here is a pic of our gripper. I think we are adding surgical tubing to make it stick to the shapes a bit better... The back part of the top of the gripper is wood...We ran out of 1/8th aluminum sheet...We are also pretty much out of money so...

To be honest I'm amazed with how much like the CAD model the robot is turning out. Last year we only had 2D CAD, and only one person knew how to use it.

This design was done using turbocad deluxe. Next year we should have a team that knows how to use AutoDesk Inventor. We are just growing and growing.

I'm hoping we can post tutorials on all of our different sub systems early next week.

Re: Team 2980's Open Source FIRST BOT
 

Things are going so smoothly I'm starting to get scared. We drove our robot today. It took a little figuring out, and some polarity switching at the motors, but we drove our robot today...And not even as a last minute thing, we drove it before we broke for lunch. Not only did we drive it then, but we got to drive it a bit after. Our driver said "I am amazed that it drives so smoothly." We've never had that happen before. We also finished welding the tower, and the arm, and got up to the first arm segment roughed in. We even got to clean the classroom up. :-)

Ok...So some pictures.

In this pick the second arm segment is just stuck in. We still haven't mounted the linear bearings that will allow it to slide back and forth. We also haven't plummed or wired the piston, or mounted the cable organizers that will allow the arm to move back and forth without ripping the wires out.


This is a much better indicator of our actual progress. We may paint the base purple and the arm gold (our school colors) but I sort of doubt that that will happen before the competition. We may do it after the competition to help raise money and awareness for next year.


This shows a close up of how the arm rotation is going to work. The window washer motor is mounted below in back. The sprocket has two holes drilled and tapped to 1/4 * 20. We used the shaft from the gearbox that came with this years kit linked to the large sprocket on the other side. Some 1/2 inch inside diameter bearings complete it all so that power can be transferred from the 60 toothed gear to the arm. The gear ratio between the windshield wiper motor and the large gear is 1:2, so I'm hoping the motor will be able to turn the arm, while retaining a reasonable turning rate. If that fails, plan B is to add a second windshield wiper motor on the other side and tie the two together.


Here is a close up of our electronics bay. We are still trying to kill the spaghetti monster lurking in there. you can also see the Pneumatics which are coming along nicely. We are using two smaller tanks, and the bigger tank that came with this years kit of parts. We figure filling the 20 inch * 2 piston we are using to deploy the minibot will use up most of the stored air even though its on the low power side of the system.


Here you can see the relief valve and power switch which are both accessible without reaching in the way of any moving parts, or anything sharp. We are a bit concerned about the gauge that is mounted on the top of the frame rail might get hit by something if another team carelessly hits it, but hopefully not.

We weighed the base, and it was only 89 pounds with everything except the tower, arm, and battery. (Battery isn't included in the weight limit). The tower weighed in at about 5, and the arm was only about 8 total, so we are actually looking at coming in right around the perfect weight. (Again, something that has never happened to us before.)

We still have a lot of work to do, our minibot is still a figment of our imagination. We also have to finish up the arm extension, and then do a final tear down, prep, and rebuild where we use locktite on all the nuts, and make sure everything is where it should be. All in all, a great day for 2980!

Re: Team 2980's Open Source FIRST BOT
 

Very detailed description and nice pictures. I like what you are doing here, keep it up.

Re: Team 2980's Open Source FIRST BOT
 

Can I ask why you chose to offset the arm to the left? Seems like an interesting design decision.

BTW the open source idea is awesome. I'm surprised more teams don't step out from behind the curtain.
I'm glad to see your team is taking a step in a nice direction.

Re: Team 2980's Open Source FIRST BOT
 

I think you should consider how you will be covering up that giant sprocket. It would probably not pass inspection for safety in it's current form.

Re: Team 2980's Open Source FIRST BOT
 

Even though it looks like a circular saw, it isn't very dangerous. many robots with a similar giant sprocket on an arm passed inspection in 2008, and I don't see why that would change in 2011.

Re: Team 2980's Open Source FIRST BOT
 

FIRST off, Thank you for the kind words.

We were thinking we would cut some lexane sheets and thin aluminum u brackets to minimize the risk of someone getting a finger caught in there. Another idea was to go get a bicycle chain cover from the recycling center and then make a bracket to mount over it. At this point it is a thought in the back of our mind...Of course the problem with covering it is that to cover it might increase the likely hood of fingers getting caught up. by creating new pinch points.

The arm and babybot launcher are offset to increase the length of the arm, and decrease the likely hood of an interaction between either of them. In its current configuration the arm will be able to reach well over 9 feet.

The camera will be mounted on a bracket on the side of the arm. This way we can use the camera during the autonomous period, and our driver can use it to line up both getting pieces and deploying the minibot. We are hoping that our driver will be able to see well enough to place the pieces on our side. If not the camera will provide the driver with an upside down view of the scoring grid.

Edoga

Re: Team 2980's Open Source FIRST BOT
 

My concern isn't that it will cut something, as it is not going that fast, but rather that someone will their hair or finger caught in there. The sprocket must be entirely covered to prevent this. You might get away with just covering the bottom where the gears mesh, it's really a judgment call.

Re: Team 2980's Open Source FIRST BOT
 

It's not even the sprocket itself that is the most significant hazard—rather, it's the point where the chain wraps around the sprocket.

Generally speaking, this is not an issue at inspection, however the precedents* for that are complicated. In 2006, for example, based upon guidance issued to robot inspectors, FIRST was adamant that the test for hazards in ball-shooting devices ought to follow from modern North American industrial practice, where finger-sized (or larger) pinch points on moving mechanisms are generally guarded. Although there were various exceptions made (mainly because that was rather difficult to implement when these mechanisms had to release balls), technically, the drive sprockets for shooter mechanisms had to be protected, because there were pinch points there. This led to quite a few unexpected rejections at inspection.

In more recent years, even with similar rules, the interpretation has been drastically different—presumably in recognition of the fact that FIRST robots are all dangerous if you stick your hand inside, but tend to be significantly less hazardous at a distance. To that end, nowadays only the most evil of mechanisms will get singled out because of close-range hazards.

In fact, you're much more likely to be called on it because of entanglement, than because of the hazard to humans. (A robot that gets its arm looped into there, or something.)

That doesn't relieve teams of the responsibility to minimize the risks to their pit crews. There's plenty of impetus for that flowing from real-world implications—but there's no universal standard or right answer to the question of "how safe is safe enough?".

*Bear in mind that precedents (recorded or not) are of limited value, firstly because the rules change every year, and secondly because FIRST doesn't recognize them as authoritative sources, even when the rules are the same. They're only guidance, made relevant principally because of the desire to keep things consistent.

Re: Team 2980's Open Source FIRST BOT
 

I see your point now, but I still disagree... The robots are very dangerous when powered, no matter what safety precautions are introduced.

I think that In the past the requirement was mostly focused on stuff which are unsafe when the robot is turned off, for example springs which store energy (2008,2010 mostly), or the requirement for a quick release valve for pneumatic systems to make sure it's easy to disarm the pneumatic pistons.

It is always a good idea to make the robot more safe, but one should be careful from being lulled into a false sense of security and safety.

Re: Team 2980's Open Source FIRST BOT
 

You're right, I was basing my opinion on precedents mostly. It's up to the team to determine if they are comfortable around that sprocket, safety-wise and inspection-wise. I would personally want to cover it up.

Re: Team 2980's Open Source FIRST BOT
 

Thank you for all of your enlightening posts. We will go over potential solutions with our safety captain, and post what we come up with later in the week.

Re: Team 2980's Open Source FIRST BOT
 

Your Robot looks in great shape and looks like you guys know what you are doing.
Last week we figured we were going to use window motors to power/controll our arm by a sprocket/chain system. Much like the one you have.

The problem is, and my question: How are you powering the window motor? we are using the 2011 KOP window motor and we did not find any connector that fits the connection on the window motor and figured we could just connect cables with fitters and electrical tape around. Then the question about which one is positive and which one is negative?

- team 3481

Re: Team 2980's Open Source FIRST BOT
 

I don't know what 2980 has done, but one of the allowed modifications is to the connector on the window motor. If you like, you can cut away the plastic and solder on more conventional leads (R47D). A little shrink wrap and you should be good to go.

Team 2577 has had good success with crimp-on quick disconnect terminals. Using insulated terminals and a bit of electrical table, we've never had a motor connection come apart during competition. Just make sure that you have a good ratcheting crimp tool.

As to polarity: it is a motor. Test it. Hook it up with clip-on leads on way and see how it spins. The window motors are slow enough to see easily which way they are turning.

Re: Team 2980's Open Source FIRST BOT
 

My suggestion: Paint it before you go to competition.

Looks matter, especially if you'd like to compete on Saturday afternoon. Between two bots, identical functionality, one painted and the other not, the painted one gets picked.

Yeah, we're all logically-minded engineers here who want to think we're all making the best decision based solely on technical merits, but--no. Looks matter.

Re: Team 2980's Open Source FIRST BOT
 

Very nice detailed Pictures!! I must say I am very impressed by your excellent use of Autodesk!! Nicely Done!!

Re: Team 2980's Open Source FIRST BOT
 

Here is a video link of how our minibot is working. Please leave some positive feedback. Thank you from F.R.E.D team 2883.http://www.youtube.com/watch?v=HZvXsaTXGfI

Re: Team 2980's Open Source FIRST BOT
 

Thanks for the kind words.

As for paint, we'll have to wait and see how we are doing on weight and money. I think we will be fine...

Window motor connectors...We cut away the plastic last year and had a motor fail because the connector broke from being stressed. A search through this forum turned up the connectors via mouser.com. You have to get the plugs and the pins separately. They totaled under $2 a piece. (we went to NAPA first and they sold us connectors that didn't fit for $28 a piece...(we returned them only loosing shipping.)

http://www.mouser.com/ProductDetail/...yGCEJfow%3d%3d
http://www.mouser.com/ProductDetail/...dZeQpqSw%3d%3d

We put some 2ton epoxy in the holes in the back of the plugs to keep things from pulling out.

So a few posts back there were questions about safety and our arm motor system. Here is what we came up with.




It is still possible to get a finger caught in there if you try really hard...We used 1/8th inch plexi and a bender to make an open backed cover. we will probably decorate it or something. The plastic protector stuff is still on there so when we peel that off the writing goes with it.

We will definitely be posting detailed tutorials on our electronics and pneumatics systems this weekend for anyone who is interested...

Hope this helps.

Edoga

Re: Team 2980's Open Source FIRST BOT
 

You may want to leave the plastic film attached to the acrylic (i.e. polymethylmethylacrylate, known as Plexiglas). It will help keep the pieces together if it gets smashed. You should be able to remove the ink markings with a solvent like isopropanol.

Next time, consider polycarbonate, which is much more impact-resistant.

Re: Team 2980's Open Source FIRST BOT
 

just noticed- your arm seems to be fairly far inside the bumper perimeter at it's lowest extension, and I am assuming it's highest as well. at present, it appears as if the arm will only be able to place on the middle, which may pose problems. Or does the tower slide forward, or the arm get longer?

based on post #6

Re: Team 2980's Open Source FIRST BOT
 

I will be posting in more detail on the arm tonight. As you currently see the arm it is facing backwards on the robot, and will flip over the top of the tower to the front of the robot. The top section of the arm is mounted on slides and can extend another 18 inches. That puts the gripper at over 9'.

Now the one major problem we have run into is getting hardware into the tiny gap between the two arm rails. We've got it done now, but it was nowhere near ideal.

Edoga

Re: Team 2980's Open Source FIRST BOT
 

Here is a short video of our minibot... http://www.youtube.com/watch?v=HZvXsaTXGfI. Check it out and give us some positive feedback. Thank you from F.R.E.D team 2883.

Re: Team 2980's Open Source FIRST BOT
 

I'm glad you decided to do this :o . It's exactly what I had in mind.

Re: Team 2980's Open Source FIRST BOT
 

what is the height of the bumper

Re: Team 2980's Open Source FIRST BOT
 

can I ask what kind of gearing you got going on there? Were trying to do something similar with a window motor.

What sized sprockets are those? How many teeth?

Thank you so much for your response

Re: Team 2980's Open Source FIRST BOT
 

@gopatterson, We should have our bumpers mounted this weekend. The plan is to have the bumpers sit about 1.5-2 inches off the ground. We will use some 2 inch angle stock to make bumper mounts. I'll post a CAD file of those once I make them. :-)

Hey Brandon, I think the big sprocket is 60 toothed and the small one is somewhere around 30. I would need to count again to get it exact. I think it may be in an earlier post on this thread.

The denso motor was not up to the job on its own. In the original design we were just using pressure to hole the plastic thing onto the front of the motor. But the weight of the arm was pulling the plastic thing out of alignment and then catching the gears. To relieve that we drilled a hole in the front bracket and shoved a plastic pacer through the hole and into the plastic thing on the front of the window washer motor.

The denso motors are not strong enough to turn the arm over on their own. We thought about using counter weights, but didn't have any available. We ended up using bungy cords as counter weights. This way the motor has to work to lower the arm making lifting the arm a lot easier. We need to add the extending mechanism which we should only need to reach the top peg.

http://www.youtube.com/watch?v=v4__hDKGQuU
That is a video. We took the plastic cover off to work on the arm, and filmed it before putting the cover back on.

Hope this helps someone.

Edoga

Re: Team 2980's Open Source FIRST BOT
 

Seems super smooth. Thanks for posting all of this it's given my rookie team a lot of help. Our arm design is about twice as long as yours and we wanted to use the window motors very similar to yours. Could you foresee any problems with using two of the window motors on separate sprocket systems nearly identical to yours to power a longer and probably much heavier arm?

Maybe using only one window motor set on a higher gear ratio would do the trick but i'm not certain.

Re: Team 2980's Open Source FIRST BOT
 

Last year we ran two window motors coupled together using a PVC pipe. Seamed to work out just fine. Make sure the motors are set to the right polarity and aren't working against eachother. Also be sure to power each motor off of its own speed controller or relay.

I'm really glad we have been able to help you. Why is your arm twice as long? We are using a slide mechanism which we will be mounting on saturday. We should have a tutorial up by sunday night.

PM me and I'll get you my phone number so that I can explain exactly how it all goes together.

Edoga

Re: Team 2980's Open Source FIRST BOT
 

Our arm design has the shoulder joint at a fixed location offset towards the back of the robot. In its starting configuration it should be about 55" long and after extension it should be 64" long. I am looking into using pneumatics for the extension but many members on my team want to use a threaded rod hooked up to one of the banebot motors.


Our material for our arm is 1" aluminum tubing with 1/8" thickness which is a little heavy duty for what were using it for but it's whats left over after we build the frame to support the arm.


Instead of mounting the large sprocket to an axle could we mount our two large sprockets directly on the arm by drilling holes through the sprockets and bolting it directly onto the aluminum tubing?

Re: Team 2980's Open Source FIRST BOT
 

Just by counting what I can see in the picture, the first sprocket looks like one of those 22 tooth sprockets, and I got around 60 on the other one.

The bungie cords are a wonderful idea! I think that's what I'm missing on ours!

You guys are amazing

Re: Team 2980's Open Source FIRST BOT
 

@ Brandon_L
Yeah..the top sprocket is 60 toothed...not sure about the bottom, but 24 sounds right.

@ Klienkid

connecting the sprocket directly to the side of the arm would have created a few different conflicts for us. First off it would make it so that the arm would interact unfavorably with the motor. Second, the chain would rub on the side of the arm, or the inside of the tower making it hard to line everything up. Remember...everything really wants to move so that the chain will bind up or come off with this setup...to be honest I'm a bit worried about the whole thing not working out...guess that is why we have the next few weeks for testing, breaking, and fixing.

You could use a pneumatic piston to extend the arm, but that has its limitations. First off, we are going to have 24 inches of extension. To get that with a piston would add a lot of weight to your arm. The threaded rod idea is cool, but the motor would have to be spinning really fast, or the threads would have to be really shallow in order to be able to extend and retract your arm at a reasonable rate. Now that I think about it, there is that weird threaded rod in the KOP that would work nicely for that...so maybe that is the way to go.

We are most likely going to use another DENSO motor. The idea is you have a round spindle, with 2 ropes or wires wrapped around it. One wire extends down over the end of the arm and then to the back where it attaches to the back of the extension slide, the other goes over the back of the arm and attaches to the front of the extension. Turning the drum winds up one of the strings while un-winding the other so that the slide is pulled forward down the arm. Turning the drum the other direction winds the back string while unwinding the front one, pulling the slide back up the arm. By shortening the arm 24 inches you are lessoning the torque required to rotate the arm around. We will hopefully have a video demonstrating this by late saturday with a tutorial on how to do it on sunday. I may be able to get drawings up by the end of the day tomorrow.

Edoga

Re: Team 2980's Open Source FIRST BOT
 

Today was one of those days. Our plan for today was to button down the last few issues with our robot and begin shooting tutorials on how everything worked. Well...Instead we found that we no longer had access to our main cRio. The second cRio that we have needed to be imaged. Needless to say our programmer spent the day chasing gremlins in the system. We did manage to shoot video of how our arm works, and video of a test of our mini-bot, but then I forgot the video camera at work.

So...today we got the backing board for our bumpers cut and mounted...We got the arm extension motor mounted, and we managed to figure out something for our minibot...So while today might have been frustrating, it was a rather productive day.
we ended up moving this to the other end of the arm because it hit the tower frame.
this kind of shows where it would hit the tower.

At the end of the day the network/cRio problems were solved, but by then it was time to go. Our team is meeting again tomorrow...which is another day. Hopefully things will run more smoothly.

The real lesson here is that all teams have their off days. The key thing is to have a good time doing it.

Edoga

Re: Team 2980's Open Source FIRST BOT
 

We used 2 window motors with 2 60t sprockets in 2007. everything was on a shaft but the arm was bolted directly to the sprockets with little spacers between them so the chain did not run into the arm. It worked pretty well, but our programmers found it hard to get our arm hold to get to move to the targeted position because it was so massive and the window motors are either on or off, no fine position movement. In the end it worked pretty well though, using surgical tubing as a counter weight.

Heres some video of it in action: http://www.youtube.com/watch?v=Ak954iBVwKg

Re: Team 2980's Open Source FIRST BOT
 

@ Cire. That arm is absolutely awe inspiring. I want our team to watch that video. I especially like the fact that you controlled it using a miniarm at your driver station. Seriously cool.

This weekend has been both good and bad for us here at 2980. On wednesday we drive the robot around. On Saturday morning...Nothing. Here is what happens. The driver station classmate says that the cRio has code. The jaguar lights go solid amber. We move the joysticks and nothing.

At this point we are concluding that it is the classmate PC. Everything else has been replaced or re-imaged. We are hoping to be up and running again in the next few days. That way we can finally shoot our electronics and programming tutorials.

We did get some other things worked out and finished.

We re did some of the welds on our frame, and welded up a practice frame.


We also took our main robot apart and cleaned it up a bit.



Here is a way to use surgical tubing to make sure your bolt heads are safe to be around. In this case these two are on the side of a linear bearing that will move back and forth. We also put them on bolts that extend into blind parts of the frame where people may put their hands. This makes it so that you can't catch your skin on the bolt and cut yourself.

We also shot a few videos explaining how different things work.

Jenn explains the pneumatics system

Clamps explains the arm

Oprah explains the mini-bot

You know your coming down the wire when you go into a hardware store and walk out with only 1 screw and 3 feet of wire. :)

Thanks,

Edoga

Re: Team 2980's Open Source FIRST BOT
 

I love what you've done with the Jaguars, mounting them to the "empty" parts of the Toughbox. What a great way to save space!

Re: Team 2980's Open Source FIRST BOT
 

The arm looks identical to ours here at team 2625 and we are sortof struggling with the code, would you be able to send it to us please? email: david@prowebdev.ca or daoud93@live.com

Re: Team 2980's Open Source FIRST BOT
 

It looks great! I finally got time to read through this thread and I am impressed, good job.

By the way the use of the term "babybot launcher" made me laugh my head off... I had some of the strangest images pop in my head. ;)

Re: Team 2980's Open Source FIRST BOT
 

@ TEAM 2980 Programmers. This post includes EDOGA CODE. You probably shouldn't look at it because Im taking you through this process step by step...Also...I don't know if it will work. so...DON'T LOOK!

@ AndyTham

I'm sort of sorry. I think I already posted this, but...Our team suffered a setback a week ago today. A student on the team made some changes in the way in which things were set up without consulting other members of the team, and then didn't come to any meetings for almost a week. This created a sort of melt down of chain events in our electronics where we could not for the life of us figure out what was done, so instead of progressing our project was completely stalled until today. We are finally where we were a week ago. I put together some code that might work. Given that I am a mentor I am taking several students through programming our robot. They just finished getting the controls to work with the drive train, and will be adding the arm controls tomorrow.


Disclaimer - This is untested code!!!!! I am running on very little sleep given that our team meets 7 days a week and as lead mentor I am there all the time!!!!! Look this over before you use any part of it.

What I made can be downloaded here. It includes what I hope to be control for the arm.

the begin.vi that I came up with didn't fit in one screen capture.



Here is the teleop code I came up with.


I hope this helps. Also, I am guiding our programmers through this process. They aren't this far yet. If anyone sees anything that is wrong with this code please post what changes need to be made.

@ Dr. Theta

Thanks for the kind words. We just hope we are helping someone out there...especially the rookies!

Edoga

Re: Team 2980's Open Source FIRST BOT
 

For anyone looking at using any part of our code. The button to victor controls are wrong. Just thought I would pass that on. The values the buttons trigger are not right so the arm goes forward, but does not stop. Easy solution is to swap out the victor for a spike relay. In actuality that makes more sense anyway because the button solution was really either on or off anyway.

The compressor code is working just fine as is the code for extending and retracting the arm. Driving even seams to be working properly. The robot wasn't on the ground so I am not totally sure.

Good luck to you all.

Edoga

Re: Team 2980's Open Source FIRST BOT
 

I realize this is a long delayed response... but I would advise you to put your router (radio) on a higher location on the robot. It will increase its range. Keeping it down with the rest of the electronics could also have a potential to cause interference. I hope this is helpful to your team

Re: Team 2980's Open Source FIRST BOT
 

@ soxfan269

While we haven't had any issues, and have even been able to drive the robot at a relatively great distance, that is an important thing to consider, so thank you for pointing it out. I'm not sure if we will move our radio at this point, but we definitely need to keep an eye on that. (one student in the club was able to pick up the wifi signal from another building on campus.)

Today was supposed to be our first testing day. Things are moving, don't get me wrong, we just want them moving faster and farther.

So...today we buttoned down the wiring, fixed some things in the teleop code, (the button control of the victor was wrong, so we swaped it out for a relay and got that all running). We realized we had a problem with our babybot extender. We were using a 20 inch piston figuring on loosing 4 inches to our linear bearings. What we forgot to take into account were the bumpers and the stop that keeps the bearings from sliding off of the back of the track. So we were really only getting 15 inches of travel, which with the inset of the babybot track meant our minibot would not hit the pole. So we started out by swapping out the 20 inch piston for a 24 inch piston.

We also had to wire our solenoids and light sensors, and mount our camera.

With that done we went on to actually get our bumpers done and mounted. This year we decided to make the red bumpers and then make a blue slip cover.

We start out making a "sock" that contains the pool noodles and backer board.



Then we sew together a slip cover that is creased on top so that it can't slip down, with elastic in the corners around the bottom. We will probably add some velcro tomorrow.

Ricky-Bobby tried to teach Cat how to sew. (he is actually much better at it than she is. :-)


Here is the gripper. We added surgical tubing to give it a bit more bite. I'm not the happiest with the geometry of the whole thing, I would prefer if it opened up wider and was more level at ground level.

So the arm sort of had a melt down today. The tension on the chain is pulling the sprockets out of alignment. I came up with a fix tonight. 2 really big brackets that hold both the Denso motor and the big sprocket in alignment.

That might make it more difficult to mount the plexiglass safety shield, but we will figure something out.

Should have more pics and video tomorrow. Were coming down the wire.

Edoga

Re: Team 2980's Open Source FIRST BOT
 

So we did a bunch of work today and got to drive the robot around a bit. Turns out the window motor overheats pretty quickly running the arm. We are currently using bungie cords, but we might have to use surgical tubing or something else instead. Yesterday we found the big sprocket on the arm was getting pulled out of alignment as it turned the arm. So today we added brackets to keep that from happening. the problem is the arm ballooned out to 28 pounds. We did some major cutting on the brackets and got it down to 26. The brackets are made from 1/4 inch thick aluminum. (all we had left) We will be ordering some 1/8 inch thick aluminum to replace them with.
http://www.youtube.com/watch?v=T-8KXDW74Oc

We also improved the rigidity of the arm mount. The slide mechanism still needs work. We will have to figure out a way to make the wire guides work better, and will probably need to make a roller system that keeps the wires where we want them.

either that or we will come up with something else. I must say I am glad we kept up the schedule we did this year giving us time to beef up the places we need to. We did end up 1 pound over weight. So spent some time cutting things back. The hard part is that that gives us very little room to grow.

This is probably the best shot of what we did to our brackets. It keeps the sprockets lined up nicely, but means we have to redo our safety shield out of cardstock or something. :-)

Right now it is a chopped of arm waiting to happen.

Finally we got started on our cart. After seeing this video we got an idea.
http://www.youtube.com/watch?v=PScY_--XAM4

We came up with this.
There will be two turn tables mounted on each tower, and the robot will sit on a tray mounted between them. We hope that we will be able to tilt the robot on its side while working on it so that we can get to things like wheels and electronics without having to move too much around.

So maybe I will regret signing us up to show off our robot at the bellingham museum of radio and electricity next Saturday...the last Saturday of build season.

What was I thinking!?

Edoga

Re: Team 2980's Open Source FIRST BOT
 

We are using an arm that weighs (I would guess) around 15 lbs including our gripper that is about 6 feet long total with 2 window motors and a 4.8:1 ratio and 2 heavy duty rubber straps to counter the weight. Our arm takes about 4 seconds to go from the bottom position to vertical. On Saturday we were noticing it was taking longer for the arm to rotate up but thought it was because our gripper was extended out and making it harder to lift, turns out one of the denso couplers had cracked and only one window motor was lifting. It was good to see that one window motor could do the job (barely). Since then we have "upgraded" our denso couplers and they seem to be holding up better (that was the 2nd one we cracked this year).

I haven't watched any video of your robot, so this could be irrevelant but I would make sure to check that the window motors can lift your arm fully extended. Our arm weighs about half yours and we have over twice a gear reduction.

Re: Team 2980's Open Source FIRST BOT
 

@ DavidGitz While the total weight of our arm is about 26 pounds that includes the base and other non-articulated parts. It would be asking a lot to try and have the motor move the arm when it is extended. We instead are planning on retracting the arm before rotating it. In fact the only time we should have to extend our arm is in order to reach the top peg.

That said we drove the robot around quite a bit today. We realized that we had the mecanum wheels mounted wrong and swapped them out. The robot handles a lot better thanks to the Chief Delphi community.

The arm seams to work a lot better especially if you don't wave it all over the place. :-) The motor was able to repeatedly move the arm without overheating, though that remains a concern.

Tomorrow we will be presenting the robot to the school board.

We just nominated two students for the Deans List award. While I'm sure what I had to say is the normal stuff to some FIRST participants, In our hearts and minds these two individuals stand out. Here is what I wrote about them.


Deans List Recommendation for Kyle

Kyle is the type of kid who seams to struggle with everything. During our “homework time” kyle is always asking for help with his history or math assignments. When working on the robot Kyle will often ask you to explain how something works several times, or how to cut out a part. As our team has grown from five to fifteen to more than thirty, there have been fewer and fewer jobs for Kyle to do. Yet still Kyle remains a fixture of our team.

There are other people on the team who are better at programming, designing, problem solving, and even fabricating than Kyle. But hands down there is no one with a bigger heart.

Last year our team found itself in one heck of a spot. Due to poor design and weight management our robot ended up being 20 pounds over weight. We discovered this when we weighed it the second to last day of the build season. Faced with a terrible choice of loosing our entire pneumatics system including our kicker and arm we decided instead to redesign our robot from scratch. Kyle worked tirelessly cutting brackets, drilling holes, sanding edges and even cleaning the room at the end of the day. While many others on the team were fading off, Kyle stayed until well after midnight.

Its Kyle who is waiting for me when I get to our Saturday and Sunday build sessions. Its Kyle who is asking to use the phone to tell his parents he will be heading home at the end of the night. Its Kyle who keeps track of where I left my coffee and its Kyle who runs to find someone a ratchet, drill bit, or even the rubber mallet. Kyle even takes out the trash. He does all of this with a smile on his face. At the regional last year Kyle spent all of his time trying to find other teams to lend parts to. He seams to love being a part of the team, and having some job that he can call his own, and we love having him.

If this doesn’t sum up the spirit of FIRST, then we don’t know what does.

Mr. Edoga and the rest of the Whidbey Island Wildcats.
Team 2980

Deans List Recommendation for Mary

Mary has been a member of the Oak Harbor Robotics Club (The Whidbey Island Wildcats) since the club first started 3 years ago. When we first started we only had 5 members and we all knew nothing about what we had signed up for. Mary Treis dove in to FIRST without a moments hesitation.

In our first year I received an envelope with a number of badges. One was green and said safety captain. Needless to say I had no idea what any of that was for, so I handed the green badge to Mary without really thinking about it. Mary being the smart girl she is went and looked up what her responsibilities were. Lets just say under her direction we are a much safer team. Mary is there to remind everyone to wear their safety gear.

Over the years our team has undergone “growing pains”. As the team has grown the responsibilities and demands placed on each member, especially the core members have decreased. Mary has gone from being a doer to being a director, and finally to being a leader. While I know she doesn’t always like delegating, Mary has taken on her new role with pride. Recently she commented that she was now a supervisor. If only she knew how important that roll was.

Our team recently acquired 6 brand new members. While they are already showing us how talented they are, they lack basic skills. Mary is always there to guide the new members teaching them the tricks that lead to straight cuts and accurate holes. She seams to know how to keep the new members occupied, and most importantly she keeps us all safe.

Mary is one of the most valued members of our team.

Edoga and the rest of the Whidbey Island Wildcats.
Team 2980

Re: Team 2980's Open Source FIRST BOT
 

Ok, that's good to hear. I think the window motors are a great asset, if you are careful with the design and minimize friction/binding as much as possible.

Overheating is a concern to us. Normally we have been using one of the large muffin fans from the KOP on each arm window motor and it keeps them ice cold, even after running for 8 hours non-stop. However today we had to turn our window motors off due to some re-wiring (and putting fence material over the blades so fingers don't go in bad places...) and the window motors over-heated after about 25 minutes of driver practice and wouldn't budge until they cooled down.

Re: Team 2980's Open Source FIRST BOT
 

It looks like you guys can cut weight out of the large sprocket

Re: Team 2980's Open Source FIRST BOT
 

I really don't see much of a problem in the logic itself, however, when I began to program I had all of my code in teleop. You might want to consider compressing some of that code into SubVi's so that it is easier to read. It was fine my first year when there wasn't so much coding, but the second year things got a little crazy and wires were EVERYWHERE so many wires... shudder.

But anyway, subvi's are a good way to compress your code and make it easier to read.

Re: Team 2980's Open Source FIRST BOT
 

Were having a big problem...

We are using two window motors into a small sprocket to a bigger 60 tooth sprocket via chain, similar to what you guys are doing:
http://i187.photobucket.com/albums/x...g/DSCN1408.jpg
(no chain is on in this picture..)

The entire setup works, but the motors like to lock up and when they do we have to put full power on them for them to unlock. The result being the arm slamming into our frame or flying into the air. Motors also tend to heat up a bit when this happens, but nothing extreme. We have two bungee cords down the back as a counterweight.

What did you guys do to prevent it from locking? We don't have a clue :(

EDIT:
I saw someone mentioning that having a jaguar controlling the arm might be doing something. I don't know if this is true, but we are using two jaguars.

Re: Team 2980's Open Source FIRST BOT
 

we recently started running into a similar problem. for us it was an alignment issue. the large sprocket attached to the arm was pulling out of alignment. That was why we added the two large brackets on the side. there is still too much play so we are adding a longer shaft when it comes in on Friday in the hopes that that will solve the problem. check the heck out of your alignment. Also I think when under strain the window motors can sort of bind up internally. It might be that you are overcoming the seasing.

finally I have heared that using some Electronic speed controllers makes the window motors unhappy. we are using a spike relay for each of these motors.

Re: Team 2980's Open Source FIRST BOT
 

We had a jaguar running our lift mechanism on a window motor and it was locking up as you've described, probably once every few up-down translations. Switched to a Victor and no further problems.

http://www.chiefdelphi.com/forums/sh...ad.php?t=83973

Re: Team 2980's Open Source FIRST BOT
 

Very nice robot! The offset on the minibot should not be a problem since you all are using mecanum wheels. a team using the ordinary wheels provided in the kit would really have trouble setting up to deploy the minibot. GREAT JOB:)

Re: Team 2980's Open Source FIRST BOT
 

I think build season is finally getting to me. Its 9 on Saturday, and I think I'm going to go to bed. FIRST things FIRST. We spent the day with our robot at the North West Robot Festival. It was really awesome getting feedback from other people, and "showing off the bot.


FIRST Team 2605 was there also. They didn't have their FRC bot, but they did have what looked like a vex bot with them that they let the crowd drive. We even teamed up on a few things.
Here their robot is putting some doughnuts on our minibot deployment tray.

Our robot did slip into demo mode which was annoying.

The shoulder problems we had been having have been fixed and seams to be working well now. We replaced the shaft that tied the right side of the arm to the sprocket with a longer one that extends out through the double bracket on the outside of the arm. (A picture would probably sum this up in half a second, and somehow I forgot to get a close up of the arm.

We did have some strange problems. The gripper solenoid valve stopped working. I think it may be jammed. The light comes on suggesting it has power. We have a spare we will replace it with and I'll blow it out with an airgun on monday. Might also be a kink in the hose...

Our arm extension mechanism also got all sorts of tangled up. The wire is getting caught in some seams in the plastic. I sort of want to come up with a better way to do this. good thing we have 5 weeks before competition.

The mini bot needs more magnets. Things were working really well back in the classroom, but when we got to the festival the minibot wheels slipped up a storm. A part of me wonders if it has to do with temperature. Maybe we should try heating up the wheels before each run...wonder how the officials would feel if we warmed up our pole before each of our matches. :-)

Tomorrow we are going to take the robot to a practice field in Lynnwood. I have the video camera in the truck already so I hope to get some good video...Course we have to fix the arm problems before we can do anything else. :-(

Still...I'm really glad we got as far as we did this year.

Edoga