This isn't an RC question, but I'm thinking of using a servo in a different application that is work related (solenoid won't work).


Supposing I set a typical hobby servo to the 20 degree position, and then I manually force it back to 0 degrees, or up to 40 degrees, and then release it after a second of two - what happens to the servo?

If the control signal is still set to 20 degrees, does it just snap back into position as if nothing happened? Or does forcing it out of position strip it out or break it? Something else?


And what if instead of maintaining the 20 degree position signal, I stopped sending the control signal after the servo moved into position (using a micro controller - not RC radio sticks), and then manually forced it out of position and released it?

Would the servo just stay where I released it with no damaged done? If so, would it know where it is, so that if I sent a signal to go to 90 degrees, would it go there, and not to say 70 or 110 degrees?


Thanks for any help.


PS. I actually do want to get a sailplane.

You will either strip the servo, or burn out the motor, or you might not even be able to force it back in the first place.

As far as removing the signal lead... Not sure but I think it would just stop and not do anything.

forcing the servo to a position that it doesnt want to be in will burn the motor or break the gears. the best way to deal with overriding a servo would be a spring loaded linkage. this would allow the servo to sit in its position and you can pull the linkage either direction up to a point, and it would return back to its original position.

Agree that forcing a 20 degree movement with signal applied is likely not going to work for very long. Most will stay put when the signal is removed.

If the signal was removed first, I don't think it's recommended but generally they can be moved at least some without harm in my experience. Yes, the servo will remember position, once the signal is restored it will go to the same positions.

Sounds like you need an actuator that includes force control as well as position control. They are available, but everything I'm aware of are quite a bit more expensive than RC stuff.

OK, thanks for the input. I was considering a spring loaded linkage or mount when I was looking at linear actuators, and this may be a good option for an RC servo too. But it also sounds like the servo may survive with the signal removed. I guess it shouldn't be too expensive to check out, and it is for a condition that I don't expect to ever happen anyway, but the boss at least wanted to cover it if we could for not too much money.

I did find a robotic servo, Dynamixel AX-12A, which would supposedly allow me to disable torque to allow it to free run, but it is $40 and more complex to interface with (but no spring linkage or mount).

Choices ... choices.