A piston with adjustable resistance?

Dear all,

I have recently come across a project that requires me to find a device that does the following,

A device that:

1)generates “0” movement
2)have a shaft that can be pulled or pushed over a distance
3)I can induce a variable resistance force to the shaft (to counter external motion)

Overall, it should looks like an actuator but the function is different- it can only resist motion and cannot generate motion on its own.

Have you heard of any devices similar?

Look for “piston dampers”, shock absorbers without a return spring. Some are adjustable. auto.howstuffworks.com/car-suspension2.htm