@sceptimatic, you are not running away now, right? I am not even finished with my explanation yet.
Start explaining properly and I'll gladly go with it.
I am explaining properly. Now, we have a piston like I described, and we can increase the length of the piston rod as it extends. As it extends, the main part/housing will go one way, and the piston rod will go the opposite way, right?
It would appear that way but in reality only the piston would go one way whilst the housing and motors stayed still.
Now you have to explain yourself. The piston rod is pushed by the motors, and the motors in turn get's pushed by the piston rod. So they should, and will, go different ways. Can you please provide information why the piston rod is different from the housing in such a way that it will not get pushed?
The motors have to be attached to the housing in order to push the piston rod, right?
Just like a conveyor belt. the motor turns the wheels that the rubber belt sits on and those wheels push that belt along.
The wheels turn one way and push the belt the other way but you only see the belt moving in one direction, not the motor housing and frame moving the other.
If you were to hang these in the air and look at them, then it would appears that both were going in opposite directions.
Like a moving car against a stationary car. It's hard to tell which one is moving when looked at side by side.
You could guess that both were moving in opposite directions if you weren't inside one with the handbrake on.
See what I'm saying?