Servo

[MASherry]

can a servo be used to turn a pvc pipe around in a 135 degree arc or does it not have enough torque? about a one foot piece of pipe.

[Billfred]

Depends on the servo and the size of the pipe.

A big 1/4 scale servo could probably do it. But a 1/10 scale servo like the ones in the kit would have a very hard time doing it. Not to mention that the gears would be cooked with one solid hit to the pipe.

YMMV.

[Robot Dude 0101]

Originally Posted by MASherry

can a servo be used to turn a pvc pipe around in a 135 degree arc or does it not have enough torque? about a one foot piece of pipe.

Why would you need to turn a pvc pipe 135 degrees with a servo? What would the application of this be?

[Cory]

I would say use a rotary pneumatic, but the only one that FIRST allowed had a rotation of 90*, IIRC

[MASherry]

we're trying to modify our bot to show sponsors this year and there is no space for a pneumatic cylinder on the outside....the servo seemed like the best bet. Once the servo turns tho, the pipe will be resting against the frame of the robot so hit's impact will be taken by the pipe and bot and not the servo.

[Andy A.]

Originally Posted by MASherry

we're trying to modify our bot to show sponsors this year and there is no space for a pneumatic cylinder on the outside....the servo seemed like the best bet. Once the servo turns tho, the pipe will be resting against the frame of the robot so hit's impact will be taken by the pipe and bot and not the servo.

This is going to depend a whole bunch on some information we don't have.

The biggest things that comes to mind for me are:

How much does the pipe weigh?

How much torque does the servo produce?

How fast does this thing need to move?

From what little I know, a servo with 100oz in of torque is considered 'high torque'. Thats pretty dinky by FIRST standards, were a FP motor can put out something like 7000 oz inch's (correct me if I messed up the math there) at stall.

Also, servos have different rotation speeds. Unloaded they are usually pretty fast, but I suspect that higher torque units may be much slower due to more gearing. And if you use a 100oz in servo to move a 100oz in load, it'll probably do it pretty slowly.

From a rules standpoint, as long as the pipe serves no competitive purpose and is just a non functional decoration, your legit. In fact, if I'm reading the rules right, you would be allowed to buy any servo you want for this use. It all still counts to your weight limit, and has to be safe. Check last years manual section on decoration. I suspect next years rules will be the same.

Just remember that servos are powered by the RC's battery, not the main 12v battery. A high powered servo can draw a surprising amount of current, and you'll have to be careful about keeping that battery charged.

So. For a yes, you can or No, you can't kinda answer, you'll need to get some more information.

Some things to think about.

-Andy A.

[greencactus3]

does it have to retract again? what if you have the pvc spring or bungee loaded and just use the servo to release a "latch" we've used this concept on every robot we create. very space saving and weight efficient. also reliable.