Research On Inductive Micrometer Non-Linear Compensation System Based On ARM

Whether in designing, manufacturing or using sensor, it is hoped that the sensor's output is linear with its input, while the relation between input and output is always non-linearized in practice. In order to increase the sensor's precision, the nonlinearity of the sensor needs to be compensated.Principle of inductive micrometer operation is based on electromagnetic induction. It achieves the electrical measurement of no-electricity (especially displacement) through the variation of self-inductance of or mutual inductance of coil. Inductive micrometer, with a low cost, high-resolution power, long life and high reliability, has been applied to the measurement of micro-displacement for a long time. It is common that the inductive micrometer is chosen as a preferred instrument in high-precision micro-displacement test.In the paper, the research work includes the designing of system hardware, the method of non-linearity compensation and the designing of system software. Firstly, the inductive micrometer requires high-speed, high real-time process system. According to the research requirements and its characters, the embedded processor PXA271 based on ARM is analyzed in details. Secondly, against the problem that the linearity of inductive micrometer is poor in wide ranges, it compares with the usual methods of non-linearity compensation, and then determines the method used in the system based on the research of characteristic curve of sensor in detail. Then, it gives the detailed designs of the embedded application software and the arithmetic of non-linearity compensation. Finally, the paper deals with experimental data and analyses the experimental results, with a conclusion shows that the polynomial fitting is a useful method to solve non-linearity of inductive micrometer.The non-linearity compensation of inductive micrometer by software has laid the foundation for its further unification and commercialization.