1726 progress - week 4

[XXShadowXX]

what do you use to turn the turret; servo, motor, or is connected right to the robot's frame

[Vikesrock]

Originally Posted by XXShadowXX

what do you use to turn the turret; servo, motor, or is connected right to the robot's frame

Their turret is powered by a Banebots RS545 through a 36mm 64:1 transmission. It has a V-belt pulley on the output that drives their "turret base" which is actually a very large V-belt pulley.

Pictures can be found here:
http://photos.project1726.org/thumbn...lbum=34&page=1

Specifically the turret motor and pulleys:
http://photos.project1726.org/displa...lbum=34&pos=15

[JoeArnold]

Nice.

[falconmaster]

As usual, Awesome! Just Awesome! I wish I were you! Way to go!

[TheOtherGuy]

Thanks for all the feedback!

I sure hope the programmers get the robot for the last week this year, that would be a first! Although we're mostly still waiting for the rest of the robot to be "adjusted" before continuing

So we basically did a small distance test today with PWM values and distance; we managed to get very consistent shots considering the variety of conditions our balls are in. Plugged into a jaguar, here are the basic results:

output(0to1)   Distance
.3-.4          0-1ft
.4-.5          2ft
.5-.6          3-4ft
.6-.7          6-7ft
.7-.8          8-9ft
.8-.9          9-10ft
.9-1           9-10ft

Not very exact (off the top of my head, I'm pretty sure it's right) but it is much more accurate than it sounds. We'll map this out and create some relationship between the motor speed and distance. We're planning on using the height or size of the target as the distance calculator. If we have time we'll add some form of revolution counter to the shooter for more a more determinate angular speed than PWM values (3500rpm is kinda fast for an encoder... I saw 111 used a reflection sensor on their 2006 robot in the "Behind the Design" book? perhaps that'll work...).

EDIT: I have been reminded to mention that the distance calculated was between the front of the robot and the back of the trailer (space between the robot and target trailer). Which may or may not be important

Originally Posted by TheOtherGuy

Not very exact (off the top of my head, I'm pretty sure it's right) but it is much more accurate than it sounds. We'll map this out and create some relationship between the motor speed and distance. We're planning on using the height or size of the target as the distance calculator. If we have time we'll add some form of revolution counter to the shooter for more a more determinate angular speed than PWM values (3500rpm is kinda fast for an encoder... I saw 111 used a reflection sensor on their 2006 robot in the "Behind the Design" book? perhaps that'll work...).

A good way to sense speed on a high velocity wheel like that would be to put a small magnet into the wheel (drill a small hole and put an iron nail in, slice the head off), and set up a hall effects sensor. Each rotation should be VERY noticeable, so you should be able to get some speeds out of that....

[Wayne Doenges]

Good looking robot and a real nice shooter.
I have one question. Will it track, and score, a moving target?

[MrForbes]

We're working on that. Still need to get several other things squared away first, but scoring on a moving target is one of our prime goals, so we will surely try our best to make it work. Our first test of this ability was kind of disappointing.

[Doug Leppard]

What size roller did you use? What is the material around the roller?

[AHS1599]

That bot looks really "screwy" Nice job!!

[MrForbes]

Originally Posted by Doug Leppard

What size roller did you use? What is the material around the roller?

The shooter and helix rollers are 4" ABS. The shooter roller has gum roughtop conveyor belting (wheel tread), the helix roller has shelf liner from Walmart, attached with aluminum strips to hold it on.




here's the only picture I could find just now...and we redid this, the flaps are each only about an inch wide now, instead of 2".

It might have some wear issues, so we may be looking for something else to use?

[Doug Leppard]

Originally Posted by squirrel

The shooter and helix rollers are 4" ABS. The shooter roller has gum roughtop conveyor belting (wheel tread), the helix roller has shelf liner from Walmart, attached with aluminum strips to hold it on.

here's the only picture I could find just now...and we redid this, the flaps are each only about an inch wide now, instead of 2".

It might have some wear issues, so we may be looking for something else to use?

Thanks that was helpful. Ours is a 5 inch running at 2500 rpm. It is not working yet other than the proto type. So these numbers give us a hint how we might be doing.

[MrForbes]

The shooter is set up with chain drive, 15 tooth motor to 22 tooth roller, from the CIM. The helix is driven by an AM Stackerbox with a CIM on it (s_forbes from our team seems to have come up with the idea of putting the CIM on that transmission, and AM put it into production), I think it's 3.57:1 ratio, driving a 9 tooth sprocket, and a 22 tooth on the roller.

[Manoel]

Very impressive!

Looks a lot like our mechanisms (helix and shooter are very very similar), except you guys are testing and debugging and we're staring at a pretty SolidWorks model yet to be built...

[RandomStyuff]

Wow, extremely impresive!

How did you make the CIM motor move by angle?