Pneumatics v. Motor
 

What would be more efficient for shooting?

Re: Pneumatics v. Motor
 

Depends on what mechanism you're using...keep in mind pneumatics will take a lot more space, add more weight, and as well have potential for many more problems than a motor...but it also has more capability of storing potential energy if you release the air explosively.

Either way, try to maximize power, initial tests with the soccer ball have shown than they can be a bit tricky to move a long distance; they're a lot denser than the orbit balls we had last year.

Re: Pneumatics v. Motor
 

Mechanisms kicking robots from Overdrive used are a good place to look for shooter ideas.

Re: Pneumatics v. Motor
 

we were leaning towards something to flick the ball to get lift or to create front spin, for those what would be beter?:confused:

Re: Pneumatics v. Motor
 

Why not set up some prototypes and test what might do what you want?

Re: Pneumatics v. Motor
 

We are I just figured I should see what other teams are going for.

Re: Pneumatics v. Motor
 

A motor will take time to spin up. While pneumatics will be alot faster. However you must take the recharge rate of pneumatics into consideration.

Re: Pneumatics v. Motor
 

Other teams are doing all kinds of interesting things. I have not seen a consensus on what works best...I've seen a video of a ball hurled very far with a rubber springy type kicker, and another of a ball hurled very far with a pneumatic kicker.

As far as I can tell, the best one to use is the one that YOUR team can make work well!

Re: Pneumatics v. Motor
 

And to your size contraints too!

Re: Pneumatics v. Motor
 

Amen to this. Judging solely by your team number, 1559 has been around for a few years. (Obviously, it may have been idle for a year or more, or have a large number of new members, etc., so "your mileage may vary".) Have you ever worked with pneumatics effectively? Do you have the skills / facilities to do custom machining? And, to some extent, how are your programming skills? These factors will weigh far more heavily for your success on the field than "are motors or pneumatics better?" (After all, if the best solution involves dielectric swizzle sticks, and you've never worked with them, what good is the answer?)

(Being finals week, I have some spare time on my hands. PM me if you want further discussion. Or discuss it here, and all teams can benefit!)

Re: Pneumatics v. Motor
 

Thats my problem , the pros and cons are about equal
my main concern is how much power willbe used and which will be beter for shooting.

Re: Pneumatics v. Motor
 

In my opinion if you can use pneumatics for numerous mechanism then go with pneumatics. Compressed air has a high upfront cost in weight (compressor, tanks, etc), but has a low cost in weight for each additional mechanism (pneumatic cylinders esp. small ones are fairly light).
Motors on the other hand have an essentially fixed weight cost. Each additional motor driven mechanism adds the weight of a motor and the requisite electronics.

As to which is better for a shooter, that comes down to ingenuity. I'm sure there are excellent designs using both and I would make that decision based on how well pneumatics integrate into what you want to do with the rest of the robot.

Re: Pneumatics v. Motor
 

That all depends on how you use it. Yes, if you're trying to use a motor to spin a kicker directly, you'll have to deal with that. However, if you use the motor to wind up the kicker and hold it in place... the release of that stored energy can be almost instantaneous - even faster than pneumatics, as you have to deal with flow rates and volumes with those. Even better, there are some pretty nice ways to translate the rotational motion of a motor into a linear motion, which can allow you to place the force from the motor away from the center of rotation of your kicker - the additional leverage means you need less torque to push it out, potentially giving you greater speed.

As squirrel said, plenty of videos are out there of teams prototyping. Thus far, i've seen teams be successful with pneumatics, springs, and surgical tubing (rubber tubing that can stretch and hold a lot of energy).

As for what our team is doing... We've been prototyping everything :)

Re: Pneumatics v. Motor
 

we were thinking about winding surgical tubing up with a motor or indirectly using surgical tubing to store energy for a foot or kicker

Re: Pneumatics v. Motor
 

That's not a bad idea, but now you get to the fun part: designing a release mechanism that doesn't burn out your motor and is safe. Pulling something back and letting go is all fine and dandy, but it's a little harder when you can't use your own hands. It's an engineering challenge if you don't go the easy route and use a transmission/clutch. I'm sure you guys can think of something, good luck!

Re: Pneumatics v. Motor
 

yea that was the problem , we got a lot of power (35-40 feet) but it was pulled back with human power::ouch::

Re: Pneumatics v. Motor
 

We are doing a CIM winder at a geardown to get about 12-15 RPM. Our winder winds up kevlar cable stretching a PRE-TENSIONED bungee group for ~12" of cable wrap to raise tension up from ~50lbs pull to about ~100 lbs pull during the wind cycle. With our winder design, a full kick wind is 180 degrees and torque at end of wind drops to near zero making triggering easier. We have a way to disengage cable from winder to allow instant cable snap back of the ~12" wind, thus delivering a force that starts at ~100 lbs and drops down to ~75lbs during the arc of the kicker 's swing when it is contacting the ball. The only mass being accelerated is the kicker, cable and bungee The rapid acceleration we get, by delivering virtually all of wind energy only to the kicker, allows use of a smaller and lower mass kicker.
With our trigger release design, as soon as 90 or 180 degree shot is released our winder is already in position for re-applying tension needed for next shot. Our winder release scheme also lets us fire at any point from 0-180 degrees during the wind up cycle, allowing us variable force release for shorter shots.

Google & read about the "mantis shrimp" mechanism for cracking snail shells by concentrating force at levels exceeding what a 22 caliber bullet can deliver. Absolutely amazing stuff!

-RRLedford

Re: Pneumatics v. Motor
 

Pictures? Please?

:)

Re: Pneumatics v. Motor
 

I don't have pictures of their robot, but I found this neat video on the mantis shrimp.

Re: Pneumatics v. Motor
 

Is This the video?

http://dotsub.com/view/39e3b18e-62d5...6-32d14121f570

the web site you posted won't load the video