A new way to control a valve positioning via electromagnetism

According to Fluid Handling Magazine, scientists at Saarland University have developed a technique to precisely control valves via an electromagnetic current, and say that it improves on conventional electromagnetically controlled valves that only have an ‘on/off’ setting.
Using a magnetically permeable metal bolt moving within a coil of wound copper wire, they apply a patent-pending control methodology that they say is ‘sensor-free’ to control the volume of fluid passing through a valve. Operators can determine the position of the bolt by analysing the electric current that flows through the coil and then adjust its position.
The way the reasearch group found to avoid noise in measure is patented, too, and relies on a series of average during the measure.
The team will be at Hannover Messe 2018, demonstrating their technology by precisely levitating a steel ball within an electromagnetic field.