Servos - How much can they lift?

[John JediMaster]

Okay my team is considering using some servos for our robot. But we need to know how much at best they could lift. Note. I'm in charge of strategy for our team so if I say something that is technical nonsense, please correct me.

Thank you.

[GregT]

Originally Posted by John JediMaster

Okay my team is considering using some servos for our robot. But we need to know how much at best they could lift. Note. I'm in charge of strategy for our team so if I say something that is technical nonsense, please correct me.

Thank you.

The servo provides 42 oz/in peak torque and rotates with a speed of .16sec/60 deg.

Let me know if you need help figuring out what those two specs mean.

[Greg McCoy]

Probably about as much as you can lift with your pinky finger

[KevinB]

Originally Posted by Greg McCoy

Probably about as much as you can lift with your pinky finger

Servos are much more stout than that ...

[Jay Lundy]

Originally Posted by KevinB

Servos are much more stout than that ...

Going by GregT's numbers I doubt it.

If you placed something 2 inches from the base of your pinky, and your pinky had the same torque as the servo, then it could lift 21 oz (about 1.3 lbs).

If anything I bet your pinky is stronger than that.

Of course there are different kinds of servos with different torques.

[GregT]

Originally Posted by Jay Lundy

Going by GregT's numbers I doubt it.

If you placed something 2 inches from the base of your pinky, and your pinky had the same torque as the servo, then it could lift 21 oz (about 1.3 lbs).

If anything I bet your pinky is stronger than that.

Of course there are different kinds of servos with different torques.

The numbers I posted refer to the Kit of Parts servo. And yes, its less then your pinky finger can lift.

Greg

[OneAngryDaisy]

Whatever you do, I would not reccomend using servos for something that requires uh... strength or consitency.. In 2001 we used a servo, or should I say 'attempted' to use a servo to latch on one of the goals. lets put it this way, we literally had to replace the servo after every match, and this was a 4v0 game with no robot interaction with eachother.

Moral: Servos inhale audibly

[KevinB]

Originally Posted by OneAngryDaisy

Whatever you do, I would not reccomend using servos for something that requires uh... strength or consitency.. In 2001 we used a servo, or should I say 'attempted' to use a servo to latch on one of the goals. lets put it this way, we literally had to replace the servo after every match, and this was a 4v0 game with no robot interaction with eachother.

We used servos to control our forward and rear goal hook in this game ... and they both worked flawlessly every time.

[Aignam]

I'd leave a servo for a small task, just to be safe. For the past two years, and perhaps this year, servos have been the essential component to 25's <sarcasm>elaborate</sarcasm> braking system.

[Joe Ross]

Originally Posted by GregT

The servo provides 42 oz/in peak torque and rotates with a speed of .16sec/60 deg.

In past rules books, FIRST has said that servo manufacturers typically inflaste their specs by 2x. So, don't count on more then 20 in/oz of torque.

[GregT]

The servo is not designed for high torque applications. Start using it for such and you'll strip the gears. I can't think of many instances its appropriate to use the servo to interact with the "outside world" (ie grabbing a goal or ball).

I just quoted quoted the FIRST KOP manual on those servo stats. If this number hasn't been correct in past years and you are depending on more then 20 or so oz/in you should probably measure the torque yourself.

Greg

[Adam Y.]

In past rules books, FIRST has said that servo manufacturers typically inflaste their specs by 2x. So, don't count on more then 20 in/oz of torque.

I have never heard that before. Could you be thinking of r/c speed controllers? Does anyone remeber what servo they are. I believe last year the were hitech servos.

[pras870]

I've never seen a servo in recent years do anything besides simple tasks (such as switching transmissions in the drill motors). They simply do not have enough torque.

[Matt D]

Everyone is telling you servos will not work for lifting, but no one is telling you what to do instead.

Use pnuematic cylinders! They are designed for lifting, you can get whatever size you need, and (new for this year) you can use as many as you want.

Skip the servos and go with pnuematics.

[pras870]

correction, you can't use as many as you want, you're limited to 4 if memory serves.