842 Final Kicker Desgin

[kE7JLM]

Originally Posted by bhsrobotics1671

So if I understand this correctly, you pull back causing it to latch, then you push the same cylindar forward, but the gate latch stops it, then you open the gate latch, causing a quicker release. Am I understanding this correctly?

Thanks so much on behalf of team 1671!

Could not be more correct, but let me give credit to team 1726. They devolved this technique in 08... Good luck to all, hope the vid helps and we will make this as safe as possible.

[Scott358]

Very nice, simple, hybrid elastic band-cylinder design!

Do you know the difference in distance by simply using the elastic band in the exact set-up, as even though you are "preloading" the cylinder and dumping the pressure on the "front" side of the piston, there still may be a negative effect by having the cylinder in the loop on the kick?

We are considering a design where the gate latch is attached to the end of the cylinder, cylinder extends to engage the kicker, cylinder retacts pulling back the kicker, and the gate latch is released when ready to kick (therefore being powered only by the elastic band). This would pretty much be the same parts, with a bit more complication in moving the latch to engage the kicker, but we're thinking we'll get higher velocity.

Any thoughts?

[Cow Bell Solo]

Originally Posted by Scott358

Very nice, simple, hybrid elastic band-cylinder design!

Do you know the difference in distance by simply using the elastic band in the exact set-up, as even though you are "preloading" the cylinder and dumping the pressure on the "front" side of the piston, there still may be a negative effect by having the cylinder in the loop on the kick?

We are considering a design where the gate latch is attached to the end of the cylinder, cylinder extends to engage the kicker, cylinder retacts pulling back the kicker, and the gate latch is released when ready to kick (therefore being powered only by the elastic band). This would pretty much be the same parts, with a bit more complication in moving the latch to engage the kicker, but we're thinking we'll get higher velocity.

Any thoughts?

Yes my thoughts i'm thinking off, how durable is that latch to deal with having to pull back with the force of of the elastic band instead of just having to hold it back into position.

[kE7JLM]

Originally Posted by Scott358

Very nice, simple, hybrid elastic band-cylinder design!

Do you know the difference in distance by simply using the elastic band in the exact set-up, as even though you are "preloading" the cylinder and dumping the pressure on the "front" side of the piston, there still may be a negative effect by having the cylinder in the loop on the kick?

We are considering a design where the gate latch is attached to the end of the cylinder, cylinder extends to engage the kicker, cylinder retacts pulling back the kicker, and the gate latch is released when ready to kick (therefore being powered only by the elastic band). This would pretty much be the same parts, with a bit more complication in moving the latch to engage the kicker, but we're thinking we'll get higher velocity.

Any thoughts?

Without using the preloaded cylinder we get about 5 feet... So the cylinder plays a big role. With the hybrid we get on average of 30 feet. With just preload (no elastic) we get about 20-25.

Good luck with your elastic design, we decided against using it because the room need to use them... and the difficulty to bringit back, but hopefully you get it!

Thanks

[Bill_B]

Originally Posted by Matt H.

In my mind an important safety practice is using parts as they were designed. I also believe safety should be a priority for FIRST teams.
As such I don't think it is unreasonable to encourage teams to purchase load rated release mechanisms such as McMaster-Carr #3899T54.

You weren't always in Arizona, right? That type device is in widespread use for holding and releasing nautical loads established by sails and rigging. While I appreciate the thought about load testing, this particular device would not close by itself, even though it might be possible to get it engaged on the retraction stroke of the piston. I will take a look through that massive online catalog to see if there is a better choice with a load specification.

[RRLedford]

Looks quite solid and consistent. Pneumatics are nice for eliminating cables & tangles.
It would seem that with pneumatic tensioning of the the bungees, you will start dropping pressure if the kicks cycle too often? Have you calculated the point of what maximum # of kicks per minute the compressor can handle before pressure starts dropping steadily?
We opted for a CIM with gear down for a tension winder because we did not feel that pneumatics could BOTH kick far enough AND frequently enough throughout the match. What is your assessment of this concern?
Our winder scheme has different issues to solve. First is how to do a trigger release of tension instantly at any point during the wind cycle (no gate latch scheme for us - we want to have programmable kick distance), . Second is how to get instant recycle to tensioning again without wasting time having winder going 180 degrees before it starts the next pull. Third, is how to keep winder rotating only in one direction without wrapping up the tension cable.
We have engineered the solution to all these issues and will be testing prototypes in the next few days.
-RRLedford

[dude__hi]

Originally Posted by RRLedford

Looks quite solid and consistent. Pneumatics are nice for eliminating cables & tangles.
It would seem that with pneumatic tensioning of the the bungees, you will start dropping pressure if the kicks cycle too often? Have you calculated the point of what maximum # of kicks per minute the compressor can handle before pressure starts dropping steadily?
We opted for a CIM with gear down for a tension winder because we did not feel that pneumatics could BOTH kick far enough AND frequently enough throughout the match. What is your assessment of this concern?
Our winder scheme has different issues to solve. First is how to do a trigger release of tension instantly at any point during the wind cycle (no gate latch scheme for us - we want to have programmable kick distance), . Second is how to get instant recycle to tensioning again without wasting time having winder going 180 degrees before it starts the next pull. Third, is how to keep winder rotating only in one direction without wrapping up the tension cable.
We have engineered the solution to all these issues and will be testing prototypes in the next few days.
-RRLedford

http://www.youtube.com/watch?v=g4-8B...eature=related

We got 3 consecutive shots at ~20ft before the tank dropped below 40psi. We only had one storage tank connected though so I think we can get 5 shots if we had all four storage tanks on before we would have to wait a while to shoot over the ramps from a fair distance. However if the other pneumatic actuators are taken into account the number is much higher.

[thefro526]

Originally Posted by Akash Rastogi

I liked the fence latch idea enough to steal it.

Hope you don't mind, FIRSTers are constantly told to steal from the best.

Seconded.

Thanks for posting up so much of your kicker design, I know it's helped me understand some concepts a lot better and I'm sure it's helped others too.

[Alex Cormier]

This is VERY interesting.

http://forums.usfirst.org/showthread.php?t=13900

[thefro526]

Originally Posted by Alex Cormier

This is VERY interesting.

http://forums.usfirst.org/showthread.php?t=13900

You're right, that is VERY interesting.

Theoretically, if a team were to have a kicker spanning the entire 38" side of their robot they could legally kick 4 balls at once...

Shoot, even kicking 2 balls at once would be awesome...

[Rohan J]

Earlier in the thread you mentioned that you were working on getting multiple shooting distances/forces. I toyed with the idea of a pneumatic cocking device for my spring-loaded kicker, but went with a motor driven winch instead so we could get multiple powers. How did you manage this with a pneumatic cylinder which only has two positions?

Also, this is what i'm using for my latch/release mechanism. The one I bought is rated to 200lbs. http://www.destaco.com/products.asp?...ory_2=Standard

[dude__hi]

Yeah we're using 4 kickers, each kicker covers its entire side of the robot minus the multiple kicker overlap.

[Ether]

Originally Posted by kE7JLM

http://www.youtube.com/watch?v=eiLiwS8p-QY

Let us know what you think, detail in the description

The tubing which feeds your cylinder is not KoP, and I did not see any solenoid valves (they might have been off-camera).

Have you tested this yet with KoP tubing and with solenoid valves? The valves are only 1/8" dia port and Cv 0.32 which makes a difference.

Also, are you pre-charging the cylinder?



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[kE7JLM]

Originally Posted by Ether

The tubing which feeds your cylinder is not KoP, and I did not see any solenoid valves (they might have been off-camera).

Have you tested this yet with KoP tubing and with solenoid valves? The valves are only 1/8" dia port and Cv 0.32 which makes a difference.

Also, are you pre-charging the cylinder?
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You are correct, the hose is not KOP but it is exactly the same stuff. We where just saving the super cool green hose for the bot. The solenoid are off camera, we are using the double action SMC.

[Ether]

Originally Posted by kE7JLM

You are correct, the hose is not KOP but it is exactly the same stuff. We where just saving the super cool green hose for the bot. The solenoid are off camera, we are using the double action SMC.

Are you pressurizing the cylinder prior to releasing the latch ("pre-loading")?

Are you using the same valve for both sides of the cylinder?

Would you be willing to share with us what part number SMC you are using?

Thanks.



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