Servo Strength

[TJ4nier]

How much weight could one of the servos from this years kit hold? The part of our robot that I'm assigned to requires a servo to hold it still until told otherwise, but I'm not sure if that will work considering the size of the part compared to the servo.

But, hey, maybe it has some hidden strength deep within that teeny little black box?

[bear24rw]

http://www.servocity.com/html/hs-322hd_standard_deluxe.html

Says its got 51 oz/in of torque

[Richard McClellan]

The servos provide 42 oz-in of torque, which is relatively low compared to a high torque servo, but it still may be adequate, just depends on how much you gear it down

[sanddrag]

The servos are rated at about 40 oz-in holding torque. Not a heck of a lot. Their typical application is moving RC airplane control surfaces or steering RC car wheels.

[AdamHeard]

You could have the servo hold a pin that holds the load.

We used a servo in 2004 to hold back the force or two arms on surgical tubing pivots to hang. It was difficult to pull by hand and the servo had no problem holding the pin that let them go.

[amos229]

Dont forget that while yes the servo may have 42 oz/in of torque, if it the piece its supporting gets jarred or knocked you will strip it out easily. I dont know if they are allowed but you can buy beefier servos with brass gears in them. Hope this helps.

[EricH]

Dont forget that while yes the servo may have 42 oz/in of torque, if it the piece its supporting gets jarred or knocked you will strip it out easily. I dont know if they are allowed but you can buy beefier servos with brass gears in them. Hope this helps.Not allowed to use other servos, as far as I know.

[amos229]

[QUOTE=EricH;557922]Not allowed to use other servos, as far as I know.

I was not sure, dial up is to slow to download manual:mad:

[Binome]

from a previous robot, don't allow servos on surfaces that can be moved by grav ity/bad humans/etc, as they WILL strip out quickly.

[Mike Betts]

I was not sure, dial up is to slow to download manual:mad:

This has got to be one of the weakest excuses I have ever heard for not reading the manual.

I have dial up... Always have...

As of 2006, 44% of internet access is dial up (J.D. Power and Associates 2006 Internet Service Provider Residential Customer Satisfaction Study).

If 44% of teams did not read the manual because "all they have is dial up", FIRST would fail miserably.

JMHO.

Mike

[ewankoff]

You limited to 2 servos for the entire robot so using a servo in another postition will leave you without the pan and tilt mechanism provided in the kit. This may or maynot be acceptable for your team.

[Qbranch]

PID and encoders/pots anyone? :D

Can give you some help to get started if you need any... just gimme a pm/email/post.

-Q

[Joe Ross]

You limited to 2 servos for the entire robot so using a servo in another postition will leave you without the pan and tilt mechanism provided in the kit. This may or maynot be acceptable for your team.

That may have been true several years ago, but this year <R45> specifically allows additional HITEC HS-322HD Servos.

The servos provide 42 oz-in of torque, which is relatively low compared to a high torque servo, but it still may be adequate, just depends on how much you gear it down

The FIRST manual used to specify that servo manufacturers typically inflate torque rating to double the actual value. So, take the 42 oz-in with a grain of salt.

[dlavery]

You limited to 2 servos for the entire robot so using a servo in another postition will leave you without the pan and tilt mechanism provided in the kit. This may or maynot be acceptable for your team.

Oh, really? Can you cite the specific rule that limits you to two servos? ;)

-dave

p.s. then read <R45>.

[ewankoff]

Im sorry i was under the impression that this rule had not changed. I guess skimming some of these rules is not a good idea. Ill go back to read every single rule word for word.

[jgannon]

Im sorry i was under the impression that this rule had not changed. I guess skimming some of these rules is not a good idea. Ill go back to read every single rule word for word.
I don't mean to abuse you any more, but just for the sake of reference, it looks like this rule has existed since at least 2005. (Specifically allowed by 2005's <R38>)

[POLISH703]

Could the servo be strong enough to motor a gripper mechanism for holding the Ringers? Has any one tried to use it for that purpose? My team is looking into doing that. The Ringers are pretty light so we think it may work.

[Brandon Holley]

servos may not be very strong by themselves, but you can design fairly simple systems using servos that achieve very effective results.

EXAMPLE: If you looked at a few teams last year (293 comes to mind), they used servos to engage pins into their drive train and lock it up therefore making a brake. Servos by themselves may be weak, but a good engineer could make servos do all kinds of things. Servos = sweet

[TJ4nier]

My team discovered as we were assembling the camera that the servos in the kit are meant to be used to pan/tilt the camera. Since we are running purely off of our KoP, we're going to try and use one of the window motors for this instance, which is sure to hold the weight.

Right?

[POLISH703]

Certainly, a window motor should be more then enough to mantipulate or power a gripper for a ringer. We just wanted to know if the servo had enough power to grip a tube because we wanted to be real minimal in weight.

[Frank Neuperger]

Rule 45 indicates additional HS322-HD servos may be used.

On Page 58/59 of Q and A, GDC indicates that the HS322-HD may be used.

This is confusing because the the sevos that came with the kit are the HS322 without the HD designation.

Does this mean that the camera must be operated with the HS322 but if you want additional servos besides the 2 for the cam, you have to get the HS322-HD?

REgards
Frank