Overcoming the control challenge (motion control)

As we study the scheme of a VFFS machine, we realize that the machine basically converts a piece of flat film into a bag filled with goods. The process of conversion involves two axes. One is the puller axis, which is aligned with the direction of movement of the plastic film; the second is the cutter axis, which is perpendicular to the direction of movement. The cutter axis must move at a fixed ratio to the movement of the puller axis. The puller axis draws the required length of foil or film, then the cutter operates and the sealer seals to provide a closed bottom to the new bag. Then the bag, which is open at the top, is filled with the material. After this action, the puller pulls the packet so that the open end at the top can be sealed by the sealer. Of course, the top end of this packet is the bottom end of the next packet.

If we plot velocity versus the time of the movement of the puller axis, it will look like a trapezoid...