Hello everybody:

I am trying to build a tennis stringing machine.Right now I have a big problem with the tighting part.

Traditional design use a liner gripper with a eletrical actuator to realize the function. My question is what kind of electrical actuator can satisfy the requirements.

1.the actuator will stop at exactly force. eg. 56 lb
2.at the end of the stroke it still hold the force as 56 lb.

This is a big question for me.If anybody can help me figure it out.

Thanks
Ray

PS
This is how the machine works. Please see the following vedio
http://video.google.com/videoplay?do...arch&plindex=1