2073 is looking into WCD, feedback requested

[philso]

The people running the wiring and the pneumatic tubing will be much happier with this version.

You may want to move the solenoids and the Spike a bit so you can move the Digital Sidecar away from the CRio to allow space for PWM cables.

You may want to mount your pressure gauge in a small, protected space in your upper structure that makes it visible.

You may also want to add a voltmeter next to the pressure gauge. We found it handy for knowing when to stop the practice and change batteries.

http://www.amazon.com/s/?ie=UTF8&key...l_4s6cbqg7iv_e

[billbo911]

Originally Posted by philso

The people running the wiring and the pneumatic tubing will be much happier with this version.

You may want to move the solenoids and the Spike a bit so you can move the Digital Sidecar away from the CRio to allow space for PWM cables.

You may want to mount your pressure gauge in a small, protected space in your upper structure that makes it visible.

You may also want to add a voltmeter next to the pressure gauge. We found it handy for knowing when to stop the practice and change batteries.

http://www.amazon.com/s/?ie=UTF8&key...l_4s6cbqg7iv_e

I may have to grab a couple of those meters for myself. let alone the robot(s).

Many of the items included in this render will not be located where they are due to the new RoboRio controller and speed controllers. No DSC's with the new controller, so that will give a bit of extra room.

Additionally, the new game will dictate changes that can't be anticipate at this point in time.

[Saool]

Originally Posted by philso

The people running the wiring and the pneumatic tubing will be much happier with this version.

You may want to move the solenoids and the Spike a bit so you can move the Digital Sidecar away from the CRio to allow space for PWM cables.

You may want to mount your pressure gauge in a small, protected space in your upper structure that makes it visible.

You may also want to add a voltmeter next to the pressure gauge. We found it handy for knowing when to stop the practice and change batteries.

http://www.amazon.com/s/?ie=UTF8&key...l_4s6cbqg7iv_e

Is there a Digital Pressure Gauge too by any chance, hopefully we will never rely on air again, but any information during a match is great to know as a driver.

[billbo911]

Originally Posted by Saool

Is there a Digital Pressure Gauge too by any chance, hopefully we will never rely on air again, but any information during a match is great to know as a driver.

With a pressure transducer similar to this one, and a digital display like this one all being driven by our good buddy Mr. Adruino, we can cook up one of our own!
Who on the team would be a good candidate for this project?

[Saool]

Originally Posted by billbo911

With a pressure transducer similar to this one, and a digital display like this one all being driven by our good buddy Mr. Adruino, we can cook up one of our own!
Who on the team would be a good candidate for this project?

Tyler 2.0, aka Daniel is amazing when it comes to Arduino, he would be perfect for this project.

[Chris is me]

Originally Posted by Saool

Thank you for the feedback. At first we were planning on using a single belt that ran inside the 2x1 but were promptly met with many issues. In this render we were planning on having the back to center wheel's belt on the inside of the frame and the front to the middle inside the tubing.

Another option would be to use wider tubing. If you aren't riveting to the top or bottom of the tube (so clearance isnt' an issue), I would recommend 2x2 tubing and 15mm belts. If you can make your own pulleys, you can fit it in 2x1.5 tubing with some creative counterbores. Since it does seem like you are riveting, 3x1.5 tube is safer, but that's definitely adding some weight.

We planned on using belts because of their minimal stretching, but after recieving all this feedback to switch to chains, we will probably be doing so.

Honestly, I think some of the feedback against belts is a bit unfair, and maybe not based on hands on experience. If you design your belts right, you should never need to perform maintenance on them inside a tube; we're going into season 5 without a belt failure. Even with an in-tube design it is possible to change a belt in 10-15 minutes if you think carefully and know what you're doing. You do not need to remove the entire gearbox to change an (internal) belt - you slide it out a few inches until the pulley is free, then slide it back in once the next belt is in place. An access window above the middle wheel will help with this. If you leave the ends open you do not need access windows on the outer wheels.

All of this said, there are compelling reasons to use chain over belt, particularly if you are running the power transmission external to the tube. Chain drive external saves weight in using a smaller extrusion profile, and I guess it saves a little space too. In the case of using belts outside of the tube, a belt drive failure would require removal and disassembly of the gearbox, and that's no fun. It's really up to preference, and whether or not you want to tension after the fact or not. If you like tensioners and bearing blocks, chain is a lot easier. If you can machine "exact centers", where your wheels are fixed the exact distance apart that a belt calls for, and you don't mind a "fatter" drive tube, belt drives are nice.

So maybe they weren't wrong... Just thought I'd add some data and explain the logic behind internal belt drives a little bit more.

[Thad House]

Originally Posted by Chris is me

Honestly, I think some of the feedback against belts is a bit unfair, and maybe not based on hands on experience. If you design your belts right, you should never need to perform maintenance on them inside a tube; we're going into season 5 without a belt failure. Even with an in-tube design it is possible to change a belt in 10-15 minutes if you think carefully and know what you're doing. You do not need to remove the entire gearbox to change an (internal) belt - you slide it out a few inches until the pulley is free, then slide it back in once the next belt is in place. An access window above the middle wheel will help with this. If you leave the ends open you do not need access windows on the outer wheels.

All of this said, there are compelling reasons to use chain over belt, particularly if you are running the power transmission external to the tube. Chain drive external saves weight in using a smaller extrusion profile, and I guess it saves a little space too. In the case of using belts outside of the tube, a belt drive failure would require removal and disassembly of the gearbox, and that's no fun. It's really up to preference, and whether or not you want to tension after the fact or not. If you like tensioners and bearing blocks, chain is a lot easier. If you can machine "exact centers", where your wheels are fixed the exact distance apart that a belt calls for, and you don't mind a "fatter" drive tube, belt drives are nice.

So maybe they weren't wrong... Just thought I'd add some data and explain the logic behind internal belt drives a little bit more.

I think a lot of people are debating belts is its possible to put too much load on certain combinations in a drivetrain. The smallest chain system you can buy is #25 chain with 16t sprockets. The torque calculations with 4 inch wheels are still within spec of #25 chain, even with 6 cims. Whereas with 9mm belts and 24t pulleys, you are out of spec for the belts. I saw alot of teams (including us) use that combination this year, and it did not work out well. Had we gone up to 30t pulleys we most likely wouldn't have broken a single belt, but if you have a baseplate mounted under 2x1, like in most WCD's, you actually cannot fit a 30t pulley without pocketing the baseplate, or spacing it out. And inside a standard WCD its harder to fit 15mm belts.

So if you make sure to put the right size belts in, they can be a great system. But I would not use 9mm belts with 24t pulleys. You will most likely have a bad time if you do.

[RandeJ]

We're also looking at WCD this year and doing something similar to your setup. We are mounting the gearbox with the WCD mounting block and then using chains & sprockets to get to the other wheels. Pic show concept - brown items are the chains (not belts).

Definitely planning some sort of chain guard/cover.