Simulation Study On LVDT-based Precision Displacement Measurement

LVDT-based Precision Displacement Measurement is widely used in industry, agriculture, medical treatment, military, and many other fields. Designers need to make improvements on the basic of the original measuring instrument because of the different application environments. Using the traditional design methods, designers must do board making and debug the system repeatedly. Therefore, it is very necessary to propose the method of using the simulation software to simulate the system. In order to shorten the development cycle and reduce development costs, we should do the PCB plate making after the simulation result meets the design requirements.This paper analyzes the measuring principle of LVDT sensor. A monolithic, linear displacement LVDT signal adjusting chip AD598 is used to design the transducer. By analyzing the AD598 and LVDT sensor, this paper designs primary coil and secondary coil combined structure which is different from the primary coil and secondary coil separated LVDT processor. The linearity of the output signal is improved. STC89C54RD+, which is produced by the STMicroelectronics company, is used to implement signal processing, equivalent conversions, system calibration, as well as serial communication of the displacement data.This paper also uses the software of Multisim to make the software and hardware co-simulation, test the system using instrument and meters provided by Multisim, analyze the test results, adjust the interactive component parameters of the system, and export the network table in Multisim to Protel for the production of the PCB.Furthermore, the LVDT-based Precision Displacement Measurement has been developed into a physical by using the simulation method. The system succeeds in 2mm length of the displacement measurement, and is able to do manual calibration. The calibration point can be decided at will. This precision displacement instrument has been calibrated in the laboratory and its resolution reaches the micrometer-grade and the repeat error is less than 1μm.