Team 254 Presents: Dropshot Technical Binder 2016

[caume]

Originally Posted by z_beeblebrox

They've got 4. See the image on page 10. The motor in the gearbox render is hidden to show the other components.

I meant to say two CIMs per side, four total. Why not use six?

[Mike Schreiber]

Originally Posted by Cherry254

The Utility arm can go into 4 positions using deployable hardstops and kickstands. Its 4 states were drive mode, Low Bar mode, Starting configuration and hang mode. The pneumatic cylinders mounted to the plates extending down at the bottom of the arm as seen on page 21. Below see the deployable hardstops.

Given an arm that needed four positions, why was the decision made to go pneumatic compared to a motor driven arm?

[JesseK]

Originally Posted by caume

I meant to say two CIMs per side, four total. Why not use six?

The only real advantages to 6 CIMs (when considering the risk of tripping the main breaker) are Powered Take Off and acceleration on an open field. Looks like 254 didn't do PTO, and the field wasn't really "open" like in some prior years.

[caume]

#35 Chain runs along the side rails running on 12 tooth sprockets to clear the bellypan

Why did you decide to go with #35 chain this year, instead of the usual #25?

Sector gears on the back are driven by the servo to adjust shot trajectory

Why did you use a servo in place of the pistons you used in 2014? I'm guessing it was for theoretically infinite hood positions, but I would think 4 or so would be enough. I guess it could possibly require some motor speed modification, but I would think that would be fairly easy...

A surgical tubing feeder roller on a dead axle is driven by a BAG motor with a compact 5-stage reducing using lightened 32DP gears.

Isn't a bag motor with a 5-stage gearbox a bit overkill...? I would think having some mechanism like a piston ball loader would be enough, or at least a bag motor with a (planetary?) gearbox with fewer stages

Thanks in advance for any response.

[microbuns]

I'm curious where the ball sat while the turret was swiveling, and how it avoided the flywheel as well as the chassis during rotation. This was our teams biggest problem with turreted shooter who went under the low bar.

[Cherry254]

Originally Posted by caume

Why did you decide to go with #35 chain this year, instead of the usual #25?


Why did you use a servo in place of the pistons you used in 2014? I'm guessing it was for theoretically infinite hood positions, but I would think 4 or so would be enough. I guess it could possibly require some motor speed modification, but I would think that would be fairly easy...


Isn't a bag motor with a 5-stage gearbox a bit overkill...? I would think having some mechanism like a piston ball loader would be enough, or at least a bag motor with a (planetary?) gearbox with fewer stages

Thanks in advance for any response.

We bagged Dropshot with #25 chain but during driver practice we broke chain often. We modified the drive train and made the change to #35 chain at CVR (our first event) and did not have any issues during the season.

A servo was used for that very reason. Having a large range of hood positions allowed us to have an accurate shot from anywhere in the Courtyard.

We initially had a delrin basket that was pulled up by pneumatic cylinders to feed the ball into the shooter. The system had many issues leading to inconsistent shots. A custom gearbox was necessary because a planetary did not package inside the hood. The feeder roller and gearbox drastically helped our accuracy along with the other shooter modifications between Week 2 and Week 6.

[Cherry254]

Originally Posted by microbuns

I'm curious where the ball sat while the turret was swiveling, and how it avoided the flywheel as well as the chassis during rotation. This was our teams biggest problem with turreted shooter who went under the low bar.

The Boulder stalled against the feeder roller and the 0.25" aluminum "horseshoe" which supports that rails that guide the Boulder into the shooter. Can see the rails and roller on page 16.

[s5511]

I'm curious as to why you guys use chain instead of belts on your drivetrains. Is there any specific reason why you guys prefer chain?

[Tal_Esh]

Any link or properties about the Fairlane wheels? Saw those on 1241's shooter as well but couldn't manage to find them online.

[Ty Tremblay]

Originally Posted by Tal_Esh

Any link or properties about the Fairlane wheels? Saw those on 1241's shooter as well but couldn't manage to find them online.

http://www.mcmaster.com/#2476k37/=12o2dgv

[apache8080]

What other wheels did you guys try out for the flywheel?

Do you guys use laser cut wood for majority of your prototypes? I assume that this makes prototyping easier and more accurate.

When is your code going to be released?

Thanks for this incredible resource.

[Michael Hill]

Originally Posted by s5511

I'm curious as to why you guys use chain instead of belts on your drivetrains. Is there any specific reason why you guys prefer chain?

Because of the design of the gearbox, it would be a real PITA to change a broken belt. Also, it lets them get away with a slimmer gearbox because belts needed in a high torque, drive situation are wide.

[Ashwin Adulla]

Originally Posted by apache8080

What other wheels did you guys try out for the flywheel?

Do you guys use laser cut wood for majority of your prototypes? I assume that this makes prototyping easier and more accurate.

When is your code going to be released?

Thanks for this incredible resource.

We bagged and tagged our robot with 2 4" Colson wheels acting as our shooter. At CVR, we used 4 4" Colson wheels. At SVR and Champs, we used 2 4" Fairlane wheels with safety wire wrapped around it to stop it from expanding a significant amount past 5000 rpm.

Yes we did use a laser cutter for prototyping with wood and it greatly aided our prototyping process as we were able to quickly CAD and test different variables for our flywheel shooter (pg 13) such as hood angle, pulley ratios, ball traction, and moment of inertia. In addition we did use the laser cutter to test out different intakes and also to cut the hubs for our mechanum wheels.

As for the code, our programming team is performing a code clean and is planning to release it soon.

[Knufire]

Do you have a source for the various SHARP sensors the technical binder mentions?

[apache8080]

Originally Posted by Ashwin Adulla

We bagged and tagged our robot with 2 4" Colson wheels acting as our shooter. At CVR, we used 4 4" Colson wheels. At SVR and Champs, we used 2 4" Fairlane wheels with safety wire wrapped around it to stop it from expanding a significant amount past 5000 rpm.

Yes we did use a laser cutter for prototyping with wood and it greatly aided our prototyping process as we were able to quickly CAD and test different variables for our flywheel shooter (pg 13) such as hood angle, pulley ratios, ball traction, and moment of inertia. In addition we did use the laser cutter to test out different intakes and also to cut the hubs for our mechanum wheels.

As for the code, our programming team is performing a code clean and is planning to release it soon.

Why did you guys switch from the Colson wheels to the Fairlane wheels?