Another Claw Thread

[anon50541363]

Hi
I have had a claw for a while, the gear ration being 1:3 with two motors, while it has been extremely successful at it’s job, we have been discussing about switching to pneumatic.
What are such pros of pneumatic over motors that will be overall better with claws??
Thanks

[Mystical_Pie]

Pneumatic will generally provide a quicker motion, and will not burn out. They will also give you access to pneumatic on other places on your robot. Also, you don’t need a 1:3 ratio on your claw with two motors. 1:1 should be sufficient.

[anon50541363]

@Mystical Pie

Pneumatic will generally provide a quicker motion, and will not burn out. They will also give you access to pneumatic on other places on your robot. Also, you don’t need a 1:3 ratio on your claw with two motors. 1:1 should be sufficient.

we tried 1:1 with torque motors, but was burning out way to fast and not enough torque , 1:3 has enough torque to life 4 stars or cubes.
Thanks for the input…

[Joseph_621]

One of our sister teams, 323Y, had pneumatics on their claw. They had enough pressure to do everything they wanted but they said that it started getting really weak at the end of matches; so much so that they were planning on switching over to motors because of it. That plus the fact that it adds a whole lot of weight to your robot.

[Connor]

Here are my opinions with pneumatics vs motors for a claw so far after scouting a competition:
Motors for the claw:

• Pros: Easier to maintain, and allows the ability to stretch as far as 1/3 the fence to plow the stars off the fence.
• Cons: May seem slow for doing such work…

Pneumatics for the claw:

• Pros: Very fast and reliable movement that activates 1/2 a second.
• Cons: Probably it won’t be wide enough to be able to plow as many stars off the fence, and you may sometimes forget to refill the pneumatic tank (If you don’t keep an eye on it).

[Mr_L_on_Yoshi]

If you do create a pneumatic claw, remember, you can double up on pistons to allow for a default position, a closed position, and a very opened position for fence knocking.

[anon50541363]

@Infinity Minus 1

I agree with this, and I would add that any sort of pneumatics have many pros and cons. You will immediately have 2 0.75 lb steel tanks on your robot, which are inconvenient and heavy. You will also have to pump the pneumatics regularly, which will slow down practice time and testing significantly (and will be extremely stressful at a competition if you misplace your pump. ) That said, you are not limited to only 2 pistons. You can use as many pistons as you want to help the lift raise, deploy a tip bar or anything else, or to release rubber bands for hanging. And, as other people have said, you have a much faster and stronger motion of the claw, resulting in a slightly faster cycle time. A motorized claw may be slightly slower, but it is lighter and faster to practice with.

Personally, I prefer the pneumatic claw, but it really comes down to what type of clawbot you are trying to create. My dumper is intended to be a very fast, 4-5 star dumper, and also has a 6 motor drive base. For teams with a 4 motor drive or higher star capacity, a motorized claw might be the way to go. But it is definitely possible to make each design viable with good optimization and good motor distribution. Good luck!

Thanks for the input, while we are keeping a 4 motor base, we want out dumper to be very fast, be able to pick up as much scoring objects and score them in least amount of time possible, I have experimented with different ratios, for the claw, so we have not tested these claw in comp, we want to build the best one possible…

[clile]

Pneumatics in my opinion are just better overall for this application. Our team had this dilemma too when making our claw. The thing that made our decision however is wanting a transmission for our lifting mechanism. However, pneumatics will offer a faster pinch rate without having to worry about motors overheating. There is also the benefit of the weight difference between two pistons, and one or two motors. These are the two main benefits our team saw when making our claw plus the benefit of using pneumatics elsewhere.

As for “will they last long enough” we tested ours this week, and using two reservoirs we were able to easily lift up 1 cube, or three stars 50 times before the grip strength became “sketchy”.

[puzzler7]

I can’t quote, but I believe that 2 pistons plus 2 tanks outweigh 2 motors by quite a bit.

[anon50541363]

@Infinity Minus 1

Oh yeah, easily. 2 motors are under a pound, while 2 tanks alone are roughly 1.5 lbs. The real question is how much efficiency you gain or lose in total when you consider the weight, speed, time to reset, and all the other factors people have mentioned.

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