The Study In Linear Output Range's Extending Of The Inductive Displacement Transducer

Inductive transducer is the measurement instrument for translation the varying displacement of parts into electric signal to output. For the excellent performances in practice such as no wear, good repeatablity, electric isolation between it's input and output and so on, the inductive transducer made up of solenoid coil is widely used for dimension measurement, it especially has the advantages in scale and precision measurement.Common inductive transducer has higher sensibility and linearity only when it's ferrite moves axially in the middle of the live solenoid coil. Hence, it doesn't be taken full advantage of its ablity, and the inductive transducer is too big, and so it's response frequency is limited. In this paper, a new way is put forward, which is to seek a special pitch varying in certain rule for winding the solenoid coil instead of the normally close-wound solenoid coil with constant pitch, so that the linear output range of the inductive transducer is expanded as large as possible.In this paper, after the principle of inductive transducer is studied deeply, the distribution of the magnetic inductive field inside the coil is investigated, and the linear output range of the inductive transducer is high lengthened when the solenoid coil winds in in a new way.The theoretical result has been verified by MATLAB simulation. According to the optimized parameters verified, the solenoid coil has been made. Based on a signal condictioner chip AD598, a measuring circuit has been designed. The circuit and together with the inductive transducer have constructed a measurement system. The system has been calibrated by inputs of accurate displacements generated by a Universal Tool Microscope. The calibrated results show that the linear output range is enlarged form percent 23 to percent 44, which validate the research of this paper. The reason which the linear output range of the real optimizing solenoid coil is shorter than the optimizing solenoid coil in theory is studied by error analysis.