Position determination and sensorless control of magnetic actuators

Solenoid actuators, especially those that are based on the reluctance principle and where mechanical work is performed by translational movements, such as solenoid valves, magnetic switches, magnetic couplings, etc., are typical control and drive elements of mechatronic systems, e.g. in vehicle technology.
In contrast to controlled proportional valves, most of these types of solenoid actuators are operated in a purely controlled manner and mechanical variables such as position and speed are not available for feedback in a control loop. Equipping with dedicated sensors is often not possible due to the small amount of space available, or it does not make sense from an economic point of view. On the other hand, knowledge of the mechanical quantities enables the potential development of numerous functions, e.g. B. in the context of noise, vibration and wear reduction, in condition monitoring and error diagnosis and also for the implementation of sensorless controlled proportional valves.
In cooperation with the Institute for System Dynamics at the HTWG Konstanz, the Chair for Systems Theory and Automatic Control deals with the development of model-based methods for position determination and sensorless control based on the sole measurement of electrical variables such as current and voltage. The research focus is on nonlinear observers and access to position determination via signal injection.

The figure shows an example of the sensorless follow-up control of the valve spool of a 4/3-way valve on the hydraulic test bench of the Chair of Systems Theory and Control Engineering. The position was determined based on the injection of a harmonic test signal.




T. Braun, J. Reuter, and J. Rudolph, A singular perturbation approach to nonlinear observer design with an application to electromagnetic actuators, International Journal of Control, 2018. DOI

T. Braun, J. Reuter, and J. Rudolph, A novel observer approach for self sensing of single-coil digital valves, in: 20th World Congress of the International Federation of Automatic Control (IFAC 2017) , Toulouse, France, 2017. DOI.

T. Braun, J. Reuter, and J. Rudolph, Sensorlose Positionsregelung eines hydraulischen Proportional-Wegeventils mittels Signalinjektion (Sensorless feedback control of a directional control valve by signal injection), at - Automatisierungstechnik, 65, 260-269, 2017. DOI

T. Braun, J. Reuter, and J. Rudolph, Position Observation for Proportional Solenoid Valves by Signal Injection, IFAC-PapersOnLine, 49, 17-21, 2016. DOI



M.Eng. T. Braun