Dynamic Compensation Design Method For Pressure Sensor Based On Digital Filter

Dynamic test technology is widely used to acquire relevant information of the tested or controlled objects in real time in various fields,such as production,scientific research,and test and so on.And the information reflects the dynamic changes of some parameters or measured variables in real time.Due to the limitations in the production process and technical level,the dynamic characteristics of the sensor as the primary part of the test system are difficult to meet the requirements of some actual tests.The test system cannot achieve real-time response and quickly and accurately reflect the tested variables,which leads to the test errors.This paper aims to compensate the dynamic characteristics of the sensor in real time.The design methods of compensation filter model based on particle swarm optimization(PSO)algorithm and digital filter based on FPGA were discussed in detail,and hardware devices that meet the test requirements were designed in this paper.First of all,the dynamic characteristics of the sensor were analyzed and studied,and the cause of dynamic error was clarified in this paper.Due to the unsatisfactory dynamic characteristics of the sensor,the working bandwidth is difficult to cover the frequency range of the tested signal,which leads to the test errors.Secondly,in order to improve the dynamic characteristics of the sensor,the dynamic calibration data of the sensor was used to establish the compensation model.The model structure and coefficients of dynamic compensation filter were estimated quickly by applying PSO algorithm on MATLAB platform.In order to verify the correctness of the model,the simulation and repeatability experiments were carried out.In the process of hardware implementation of compensation model,the implementation structure of the IIR digital filter and the finite word length effect need to be considered.Because of the feedback links in the structure of IIR filter,the conventional direct type structure has low precision and is greatly affected by the parameter quantization.The accuracy of thecalculation result is low and the calculation process takes a long time.In this paper,according to the simulation results,the appropriate quantization bits of the coefficients and the output data were selected,the cascaded implementation structure was used,and the soft core design of digital filter was completed.Finally,FPGA as the control and processing core was used to design the real-time dynamic compensation circuit system which includes data acquisition,storage and reading.The performance of compensation system was verified by shock tube device.The rationality,feasibility and correctness of the real-time dynamic compensation structure are verified by comparing the test results.