Just a Robotics Question (need ideas from the smarts)

[Weird Al/ Tony]

Hi. I'm usually on here to ask questions. so thats what i'm doing today. oh and the flint car show was fun with the teams that went. anyways. I am usually asking questions for my own personal robot which is a battle bot in the making. I am on a team but since it's the off season we're just fixing and editing for the off season kickoff in september. anyways the question i have is in relation to my robots pincers. I am designing them to close in a side ways motion(one on each side). I am planning to power them using pneumatics, to push out on the back of the pincers behind the main joint in order to close the front. the pincers will be a foot and a half long infront of the rotation point, and half a foot behind it. the back will also come in slightly for spaceual reasons. I believe it to be a working design. it is based off of Dead Metal from robot wars (british) if you have any ideas on an efficient/cheap/working pincer idea or design it would be greatly appretiated.

[Doctorwho]

Can you give a sketch of what your general idea is?

[Hawiian Cadder]

what?!?!?!?! go for a full body spinner like megabyte.

[Chris is me]

Pincers aren't particularly effective in combat robotics, from what I've learned / experienced last year. You have a protruding and fairly specific end effector that's likely to be vulnerable to a bar or full body spinner as there's not much to grab.

[Jeffy]

Well, Pincers, grabbers, crushers, ect. don't really use kinectic energy much of an advantage, so hydraylics or a linear actuator could work just as well. From my experiance with combat robots, the weight restriction is very much more difficult than it is in first. With that said, I would go with the simplest mechanism and use a linear actuator.

Head the above posts. One small suggestion: Robots have large varieties in shapes and widths, however, their is a much smaller variation in height and most combat robot tops are flat or close to it. This would give an advantage to an overhead crusher.

I have been out of combat robots too long to remember the name of the robot I am thinking of, but it was the only semi-sucessful crusher that I have ever heard of. It believe it was a Canadian bot, and either a 1 kilo or 3lb robot. (my expertise is in small parts and robots, sorry)

[IKE]

What weight class are you building for? This would help in recommendations that could range from high strength salad tongs to the jaws of life.

[joeweber]

To those that are not aware BattleBots may be returning in November 2010 in San Francisco. visit http://www.battlebots.com/BattleBots.com/Home/Home.html

Lets get building destruction.

[DonRotolo]

Remember that in battlebots pneumatics of 1000 PSI are not unheard of. So power will be plentiful.

I also don't like the idea, since pincers are vulnerable, but nonetheless:

One issue with pleumatics is that the darned actuator cylinders are so long: Retracted they are about 4 or 5 inches longer than the 'throw' of the piston, so for a 6" actuation you need about a foot.

Two cylinders will give you twice the grip, as opposed to a single cylinder acting on both arms equally. You can also operate them independently, whacking outwards if that's advantageous at the moment. Sorta like a smack upside the head.

Hydraulics will be just too slow, if the intent is to 'whack' the opponent. If you intend to grab and crush the opponent, hydraulics have the advantage, in that the fluid is not compressible. Think jaws of life.

In either case, both ends of the cylinder need to be pinned with one degree of freedom, since the angles to the chassis and the pincer will vary.

If you push with 1 ton at the 6" end, your 18" end will see 1/3 ton. Do what you can to reduce the long end and increase the short end, to get more strength. But if speed is the weapon (think fast hammer) then inertia will do the work, and your 6"/18" would probably be good. The business end tips need to be hard and heavy, perhaps with spikes pointing inwards to inflict maximum damage and get a good grip. But gripping a massive spinner may toss your robot pretty hard, bend the arms, or worse. But imagine if you could dig in and hang on! Wow, that'd stop that spinner real good.

massive axles, 2" diameter by 1/2" wall aluminum might be strong enough. Roller bearings for sure, top & bottom. Larger diameter can handle a lot more stress. a 1/2" bolt will tear right out.

Your arms need to be strong on the side to side direction, but not so much up and down. But guard against the sledgehammer bots, those arms are so very exposed.

Weight class and sketches will help.

[CENTURION]

perhaps this will give you some insight.

http://www.youtube.com/watch?v=vkwL3r4r71M

in short, the pincers are pulled together by a single hydraulic piston (used in a pneumatic system)