Study Of Angular Displacement Inductive Transducer And Its Structure Analysis

The measurement of displacement is very important in engineering. Inductive displacement transducers are widely used due to their simple structures, high output capacities, good linearity, good disturbance resistance, good stability and low prices. Based on thoroughly analysis of linear inductive displacement transducers, a new inductive angular displacement transducer were designed in this thesis.A comparative study of varies inductive transducer structures was conducted in this thesis, with the coil type inductive transducers were emphasized. The FEM was used to analyze the magnetic fields in the coils of this type of inductive transducers. Based on above analysis, a new structure of inductive angular displacement transducer was designed, in which the mutual inductance changes proportional with the rotation angle of the core. The commercialized FEM software ANASYS was employed in the analysis of the magnetic field in the transducer. The distribution maps of the magnetic field and the output specification curves were obtained by the FEM analysis. The affections of the structure parameters to the output specifications were also studied. It was found that in a specific range, the mutual induction changes linearly with the angular displacement It was also concluded that the smaller the structure gap, the bigger the transducer output.The correspondent amplifier circuits were also discussed in this thesis. Three type of practical circuits were given.Finally, the calibration data of three experimental angular displacement transducers were given, which shows that the linear range is no less than +/- 50 degrees with linearity error less than 0.41%. When a bigger linearity error, namely 1.9%, is acceptable, the linear range will exceed +/- 60 degrees accordingly.