scholarly journals Compensation Method for Polarization Mixing in the Homodyne Interferometer

2020 ◽  
Vol 10 (17) ◽  
pp. 6060
Author(s):  
Chaoqun Wang ◽  
Qiangxian Huang ◽  
Xuemeng Ding ◽  
Rongjun Cheng ◽  
Liansheng Zhang ◽  
...  

A homodyne interferometer is one of the most important tools in nanometre measurements. However, its nonlinear error seriously affects measurement accuracy at the sub-nanometre level. As one of the dominant factors that cause nonlinear error in a homodyne interferometer with a quadrature detector system, the imperfection of polarizing beam splitters (PBSs) is investigated in this paper. The nonlinear error caused by the imperfection of PBSs in the detection part can be reduced by adjusting the gains of detectors. Nevertheless, eliminating the nonlinear error caused by the polarization mixing of the PBS in the interferometer part is difficult. In this paper, the nonlinear error caused by the polarization mixing of the PBS in the interferometer part is analyzed, and an optical compensation method is proposed to correct this polarization mixing. Theoretical calculation and simulation analysis show that this method can reduce the effect of inherent polarization mixing on nonlinear error significantly. In comparison with using only gain adjustment, the nonlinear error can be reduced by two orders of magnitude when the proposed method is applied. The nonlinear error can be decreased from approximately 4.5 nm to approximately 0.045 nm using the presented method based on the simulation results.

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Lei Xu ◽  
Ning Zhang ◽  
Liqing Fang ◽  
Huadong Chen ◽  
Pengfei Lin ◽  
...  

The magnetic gradient full-tensor measurement system is diverse, and the magnetometer array structure is complex. Aimed at the problem, seven magnetic gradient full-tensor measurement system models are studied in detail. The full-tensor measurement theories of the tensor measurement arrays are analyzed. Under the same baseline distance, the magnetic dipole model is used to simulate the measurement system. Based on different measurement systems, the paper quantitatively compares and analyzes the error of the structure. A more optimized magnetic gradient full-tensor measurement system is suggested. The simulation results show that the measurement accuracy of the planar measurement system is slightly higher than that of the stereo measurement system. Among them, the cross-shaped and square measurement systems have relatively smaller structural errors and higher measurement accuracy.


2015 ◽  
Vol 779 ◽  
pp. 62-67
Author(s):  
Ze Yin Shan ◽  
Rui Bo Yuan ◽  
Chao Li

Plunger pair of plunger water hydraulic motor has the problem of leakage. Simulation of the leakage of plunger pair of plunger water hydraulic motor is carried out. Through calculation and analysis establish the model of plunger pair of plunger water hydraulic motor. The simulation analysis of leakage of plunger pair was carried out with Fluent software. Theoretical calculation and simulation results of plunger pair are obtained. The results provide basis and method to reduce the leakage of plunger water hydraulic motor and design for the motor plunger.


2011 ◽  
Vol 71-78 ◽  
pp. 4624-4627
Author(s):  
Lei Sun ◽  
Wei Ming Feng

This paper used the finite element method to simulate the engineering structure for large complex steel truss structure installation plan. The simulation results provide the basis for the scheme selection, and it is compared with the measured results and theoretical calculation to prove that the simulation technology is necessary and correct.


2011 ◽  
Vol 130-134 ◽  
pp. 2709-2714
Author(s):  
Tian Hao Peng ◽  
Nan Geng Yue ◽  
Jia Dong Liu ◽  
Mei Sheng Yang

This paper analyzed the reasons of motor speed loss under variable load in variable-speed pump-control-motor governing system, and pointed out that oil compressibility caused by load change is one of the reasons. Speed drop compensation coefficients ware derived, and the compensation method under variable load in variable-speed pump-control-motor governing system was built. The simulation results show that the compensation method can well compensate motor speed loss in variable load.


2010 ◽  
Vol 135 ◽  
pp. 376-381 ◽  
Author(s):  
Hua Li Zhang ◽  
Ji Cai Kuai ◽  
Fei Hu Zhang

The properties of oxide films are very important for improving the mass of ELID grinding surface. In this paper, a novel calculation model of thickness of oxide films was proposed; the theoretical calculation and simulation analysis were developed, and were compared with the corresponding experimental results. The results proved that the theoretical calculation and simulation results of the thickness of the oxide films had good agreement with the experimental results. This model could predict precisely the change of thickness of oxide film, the instinct of non-linear electrolysis was explained from a novel aspect of ability of pulsed electrolysis. This model could be used in the on-line control of electrolytic state during practical ELID grinding process.


Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4419
Author(s):  
Ting Li ◽  
Haiping Shang ◽  
Weibing Wang

A pressure sensor in the range of 0–120 MPa with a square diaphragm was designed and fabricated, which was isolated by the oil-filled package. The nonlinearity of the device without circuit compensation is better than 0.4%, and the accuracy is 0.43%. This sensor model was simulated by ANSYS software. Based on this model, we simulated the output voltage and nonlinearity when piezoresistors locations change. The simulation results showed that as the stress of the longitudinal resistor (RL) was increased compared to the transverse resistor (RT), the nonlinear error of the pressure sensor would first decrease to about 0 and then increase. The theoretical calculation and mathematical fitting were given to this phenomenon. Based on this discovery, a method for optimizing the nonlinearity of high-pressure sensors while ensuring the maximum sensitivity was proposed. In the simulation, the output of the optimized model had a significant improvement over the original model, and the nonlinear error significantly decreased from 0.106% to 0.0000713%.


2014 ◽  
Vol 602-605 ◽  
pp. 3434-3437
Author(s):  
Yu Kun Chen ◽  
Ke Yin Wang ◽  
Hai Ying Huang ◽  
Pai Hang Zhao

This paper analyzed the formula for calculating the velocity and scatter radius of water mist droplets after detonation. Through establishing model, calculating by the formula and simulation of theoretical model, the reasons of deviation between calculation and simulation results were found out. In order to make theoretical calculation more accurate and applicable, new formula was created by introducing correction factors.


2021 ◽  
Vol 11 (14) ◽  
pp. 6514
Author(s):  
Lu Wang ◽  
Yuanbiao Hu ◽  
Tao Wang ◽  
Baolin Liu

Fiber-optic gyroscopes (FOGs)-based Measurement While Drilling system (MWD) is a newly developed instrument to survey the borehole trajectory continuously and in real time. However, because of the strong vibration while drilling, the measurement accuracy of FOG-based MWD deteriorates. It is urgent to improve the measurement accuracy while drilling. Therefore, this paper proposes an innovative scheme for the vibration error of the FOG-based MWD. Firstly, the nonlinear error models for the FOGs and ACCs are established. Secondly, a 36-order Extended Kalman Filter (EKF) combined with a calibration method based on 24-position is designed to identify the coefficients in the error model. Moreover, in order to obtain a higher accurate error model, an iterative calibration method has been suggested to suppress calibration residuals. Finally, vibration experiments simulating the drilling vibration in the laboratory is implemented. Compared to the original data, compensated the linear error items, the error of 3D borehole trajectory can only be reduced by a ratio from 10% to 34%. While compensating for the nonlinear error items of the FOG-based MWD, the error of 3D borehole trajectory can be reduced by a ratio from 44.13% to 97.22%. In conclusion, compensation of the nonlinear error of FOG-based MWD could improve the trajectory survey accuracy under vibration.


2021 ◽  
Author(s):  
Qiongxiao Wu ◽  
Jianjun Wang ◽  
Jingming Chen ◽  
Pengzheng Li

Abstract Based on the one-dimensional simulation model of lubricating oil system is established and analyzed by using FLOWMASTER software, this paper proposes a new method of optimizing lubricating oil system by PID technology. Ensure that the configuration requirements and control strategies of the relevant accessories of the simulation model are satisfied with the design requirements. Firstly, by simulating lubricating oil pressure fluctuation and lubricating oil flow distribution under Open/Close Valve in different opening and closing time, the optimal opening/closing time of Open/Close Valve is determined to be 0.2 s and 0.5 s respectively. Secondly, by writing the controller script file combined with a controller to realize automatic unloading relief valve simulation, determine the relief valve pressure regulating range of 0∼0.38 MPa, For precision of constant pressure valve of oil spill, the simulation results show that the average 10 m3/h flow caused by pressure changes of about 0.06 MPa. Under the flow sudden change signal of about 40 m3/h, the maximum pressure change is less than 0.1 MPa. Through the simulation results, it is found that most of the lubrication parts in the original design have the phenomenon of flow redundancy, which causes unnecessary pump power loss. The system is optimized by PID technology. By comparing the simulation results before and after optimization, it is found that the speed of constant displacement pump could be changed in time by PID controller, and the flow redundancy could be improved significantly, so the lubricating oil system could be lower consumption and achieve the purpose of optimization.


Author(s):  
Yangbing Zheng ◽  
Xiao Xue ◽  
Jisong Zhang

In order to improve the fault diagnosis effectiveness of hydraulic system in erecting devices, the fuzzy neural neural network is applied to carry out fault diagnosis of hydraulic system. Firstly, the main faults of hydraulic system of erecting mechanism are summarized. The main faults of hydraulic system of erecting devices concludes abnormal noise, high temperature of hydraulic oil of hydraulic system, leakage of hydraulic system, low operating speed of hydraulic system, and the characteristics of different faults are analyzed. Secondly, basic theory of fuzzy neural network is studied, and the framework of fuzzy neural network is designed. The inputting layer, fuzzy layer, fuzzy relation layer, relationship layer after fuzzy operation and outputting layer of fuzzy neural network are designed, and the corresponding mathematical models are confirmed. The analysis procedure of fuzzy neural network is established. Thirdly, simulation analysis is carried out for a hydraulic system in erecting device, the BP neural network reaches convergence after 600 times iterations, and the fuzzy neural network reaches convergence after 400 times iterations, fuzzy neural network can obtain higher accuracy than BP neural network, and running time of fuzzy neural network is less than that of BP neural network, therefore, simulation results show that the fuzzy neural network can effectively improve the fault diagnosis efficiency and precision. Therefore, the fuzzy neural network is reliable for fault diagnosis of hydraulic system in erecting devices, which has higher fault diagnosis effect, which can provide the theory basis for healthy detection of hydraulic system in erecting devices.


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