| Precision angle measurement technology is an important guarantee for the accuracy of high-precision and cutting-edge rotating equipment,and it is the core measurement technology means related to high-refining and national defense military industry.Having the absolute advantage of angle measurement accuracy means having the scientific and technological strength to manufacture high-end equipment.Traditional absolute angular displacement sensor relies on encoding technology and ultra-precision processing method.In order to overcome the limitation of sensor processing accuracy on measurement accuracy,this paper presents an angular displacement measurement sensor with multi-loop structure,which is jointly coupled by multiple physical fields,based on the basic theory of original research work on time-grid sensors in China and using the combination of positioning and measurement.The sensor in this paper can measure the amount of space by measuring the amount of time.It has good performance and is especially suitable for complex working conditions.The main contents of this paper are as follows:(1)Based on the basic theory of electromagnetism and the principle of equivalent circuit of differential capacitance,and based on the time-grating sensing theory,the distribution of electromagnetic field and the change of output signal during the coupling process of magnetic field and electric field in the inner and outer rings are analyzed,the physical model of sensor based on the mutual coupling of magnetic field and electric field is established,and the method of absolute position decoupling is designed.(2)Single magnetic field coupling,single electric field coupling and electromagnetic multi-field coupling are modeled and simulated respectively by using the electromagnetic field finite element analysis platform.Based on the single-loop simulation results,the optimal parameters such as the height of the installation gap of the sensor’s magnetic field circuit and the electric field circuit,the installation horizontal parallelism,and the installation coaxiality are analyzed.Based on the simulation results of the inner and outer rings,the crosstalk errors between electromagnetic fields are analyzed and the suppression methods are proposed.The sensor structure is optimized by simulation analysis.(3)The sensor’s electrical system is designed using field programmable logic gate array(FPGA)processor and related signal processing circuit,which includes hardware circuit and software program.(4)According to the simulation model,two sets of sensor prototypes before and after optimization are made by using the printed circuit board(PCB)process,and an experimental platform is set up according to the requirements of prototype installation.At the same time,carry out the experimental verification of the sensor in this paper,verify the correctness of sensor function and performance reliability,and finally complete the error correction.The results show that both the in-pole measurement error and the whole-week measurement error of the optimized sensor are significantly reduced.After 360° correction of the optimized sensor,the measurement error of the precision machine is 19″,and the positioning error of the precision machine is 58″.The angular displacement sensor developed in this paper can make full use of the advantages of strong anti-jamming ability of the magnetic field type and high accuracy of the electric field type.At the same time,the sensor in this paper has simple structure,mature processing technology and low cost,and has important application value. |
