Microwave Displacement Sensor for Hydraulic Devices

This paper presents the fundamentals, design, realization, and characterization of a state-of-the-art microwave based piston position detection sensor for position detection of stationary or moving pistons in industrial hydraulic devices. This function has a high importance in industrial applications to provide precise feeding in position controlled hydraulic drives (classical actuators, medium separators, and pressure accumulators). Microwave technology is established in many sectors except for factory automation. In this paper, we describe an initial minimally invasive and contactless implementation of this technology for the above mentioned industrial applications. It is suitable for small but also for large piston stroke ranges in rugged industrial environments and is able to fulfill the tough specific requirements.