Metrological Analysis of a Contactless Inductive Position Measurement System

Inductive sensing offers a versatile approach for the realization of position sensors. Advantages of inductive sensing are its robustness with respect to environmental influences, such as dust, humidity, or pollution. The technique also allows the realization of contactless sensors, i.e. sensors without any connection elements. A flexible approach for contactless position sensing is based on voltage measurements between a transmitter coil and an array of receiver coils. E.g. the approach has also been presented for 3D tracking. In this work we study the characteristics of such a system for linear position measurement. The work is based on simulations and comparative measurements. Aspects for the modeling of the inductive coupling are addressed and verified by measurements. Based on this, the elements and exemplary results for an uncertainty quantification for different coil arrangements are presented. Finally a model based approach to assess different coil arrays by means of the Cramér-Rao lower bound (CRLB) is presented.