Method and system for controlling a free piston mover

A method of controlling a Free Piston Mover, the method comprising the steps of:

• generating a Control Parameter Set for closed loop control of a Target Control Variable, this set comprising a Target Control Variable Function together with one or more of:
• a Stroke Threshold Function;
• a Feed Forward Current Function;
• a Feedback Terms Function;
• Control Parameter Set Transition Conditions;
• transmitting the Control Parameter Set to an In-Stroke Controller in advance of the start of a Stroke to be controlled;
• modifying one or more of the constituents of the Control Parameter Set for any-Future Stroke of the Free Piston Mover using a Future-Stroke Controller;
• transmitting the modified Control Parameter Set to the In-Stroke Controller for the control of any Future Stroke;
• sampling a Base Variable indicative of Free Piston Mover performance during a Stroke following the generation of the Control Parameter Set;
• generating at least one Target Control Variable using the measured Base Variable with reference to a Target Control Variable Function;
• determining at least one Control Variable Error using the measured Control Variable and the Target Control Variable;
• generating a Current Demand output which is input to a Current Controller using the Control Variable Error;
• sampling a second Base Variable indicative of a second Free Piston Mover performance;
• generating at least one second Target Control Variable using the measured second Base Variable with reference to a second Target Control Variable Function;
• determining at least one second Control Variable Error using the measured second Control Variable and the second Target Control Variable;
• generating a Current Demand output which is input to a second Current Controller using the second Control Variable Error;
• and
• modifying the second Target Control Variable Function for a future stroke of the Free Piston Mover using a Future-Stroke Controller which may affect the next stroke or any future stroke.