Robot DC- The nipple arms move forward and backward on the same set of spokes

The nipple arms move forward and backward on the same set of spokes after they have already worked on them

There are two sensors in the nipple arms: one detects the forward movement, and the other detects the return. When the arm moves forward, one sensor should be on and the other off. When the arm moves back, the first sensor should turn off and the second one should turn on.
The machine is attempting to return the arm to the same position twice or more

see example:

To avoid this, try adjusting your sensors :

Keep in mind that it is also possible that the cylinder is faulty or that something is blocking the movement.