Claw

[farmersvilleRob]

We are looking at servos for our arm, but we aren't sure exactly how fast 60 degrees/.07 seconds is. We understand it's very fast, but is there something we could compare that to to get an idea? it's the fastest available which is what we need, lol

I'm no motor expert, but I think you may want to use something a bit stronger than servos for your arm, especially if it's going to be picking up basketballs and scoring them.

[JosephC]

Originally Posted by SuperNerd256

I'm no motor expert, but I think you may want to use something a bit stronger than servos for your arm, especially if it's going to be picking up basketballs and scoring them.

I'm no motor expert either, but from personal experience you should use something stronger then a servo.

60 degrees in .7 seconds is the same as 85.7 degrees per second, or ~ 4.1 seconds for a full 360.

[farmersvilleRob]

oops, I meant claw, lol its still too early today 2:30 pm... lol

[EricH]

Originally Posted by farmersvilleRob

oops, I meant claw, lol its still too early today 2:30 pm... lol

Still a bit on the light-duty side for a claw.

You might try a VEX motor, a pneumatic cylinder, or a small-ish BaneBots motor to get a better performance.

[JosephC]

Originally Posted by EricH

Still a bit on the light-duty side for a claw.

You might try a VEX motor, a pneumatic cylinder, or a small-ish BaneBots motor to get a better performance.

If weight is a issue then the VEX motor would probably be best, other than that my motor guys tell me that the small-ish BaneBots motor is the way to go.

[farmersvilleRob]

Well I need a lot of speed. preferably as close to 0 as possible.

But in reality weight is an issue, and I would like for it to be extremely lightweight.

The VEX motor does 60 degrees in .01 seconds so that's good!
But it's only got ~216 ounce inches of torque :/
And it weighs .2 pounds which is fine.

Now I guess I could put a gearbox to the motor, but that makes it too heavy.

[EricH]

Originally Posted by farmersvilleRob

Well I need a lot of speed. preferably as close to 0 as possible.

But in reality weight is an issue, and I would like for it to be extremely lightweight.

The VEX motor does 60 degrees in .01 seconds so that's good!
But it's only got ~216 ounce inches of torque :/
And it weighs .2 pounds which is fine.

Now I guess I could put a gearbox to the motor, but that makes it too heavy.

Gang two VEX motors. Use VEX gears to link them and an output gear on a rail. VEX gears are light; I don't think the entire setup would weigh over a pound, rail included.

[farmersvilleRob]

Originally Posted by EricH

Gang two VEX motors. Use VEX gears to link them and an output gear on a rail. VEX gears are light; I don't think the entire setup would weigh over a pound, rail included.

But thats still less than a usable servo, and the servo runs straight off the arm. If I was going to do an add on as well, I might as well go with a servo gearbox and output 2000 ounce inches

[EricH]

Originally Posted by farmersvilleRob

But thats still less than a usable servo, and the servo runs straight off the arm. If I was going to do an add on as well, I might as well go with a servo gearbox and output 2000 ounce inches

2000 oz-in and very, very, very slow rotation. Remember your limitation on servo power.

You need both speed and some power, so a servo probably isn't the device you want. You're saying a VEX motor doesn't have the power. Well, that leaves either a light Banebots or a small pneumatic cylinder. If you aren't otherwise using pneumatics, then the pneumatic cylinder is not going to help weightwise (because then you have to add a full system somewhere). That leaves a light Banebots motor (probably the RS395), or maybe some of the other lighter allowed motors.

Or... Wait, would a 1-inch throw electrical solenoid actuator work? How about a Denso throttle control motor? What about an AndyMark motor or gearmotor?

[farmersvilleRob]

Could you post links to one of those 1-inch throw electrical solenoid actuators and Denso throttle control motors so I can research them?

Pneumatics is a waste for use to mount and barely use. And the bane bot motor weighs 12.4 ounces, and we need 2 for each side of the claw. That leaves barely any room for the actual parts (let alone the gearbox) because we're calculating a max weight of 3 pounds.

I guess this probably wasn't the right thing to ask because I can't provide too much information without saying our designs, but once I look at those two, I should be able to come up with a decision with the team! Thanks in advance!

[farmersvilleRob]

I found both. They aren't what we need, but I think I'll stick with servos

[JosephC]

Good luck then, and see you at the competitions.