Study On Precise Constraint Method Of Time-varying Magnetic Field And Its Application In Time Grating Sensor

With the development of automation and intellectualization in global manufacturing industry,open-loop control and semi-closed-loop control will be gradually replaced by full-closed-loop control in industrial field.As the key component of the position information-feedback,the performance of displacement sensors has much influence on the whole control system.The inductive displacement sensor has been widely used,because this kind of sensor has high stability,high reliability,strong anti-interference ability and strong adaptability in the environment.The distribution and propagation of magnetic field have much influence on measurement precision of the inductive displacement sensor.At present,the distribution and propagation of magnetic field in the sensor are not as good as expected,so the original measurement accuracy of the sensors is affected by the distribution and propagation problems.The inductive time gating sensor also has those problems,the constraint method of time-varying magnetic field in the sensor is an indispensable step in the process of sensor development.In order to meet the demand for miniaturized sensors in the industrial field,the volume of the time gating sensor needs to be improved.This paper presents a precise constraint method for time-varying magnetic field,and the research on two new time gating displacement sensors has been implemented based on the constraint method combined with the time grating measurement theory,.The work and achievements presented in this paper are summarized as follows:(1)According to the research on the generation principle of time-varying magnetic field and the constraint method of planar magnetic field based on electromagnetism theory,the precise constraint method for time-varying magnetic field is proposed.There is an expected sine relationship of time grating displacement sensor between the output signal of the induction coil and the displacement by using the constraint method,which promotes the research of the new time gating displacement sensors working on time-varying magnetic field.(2)Combining the precise constraint method of time-varying magnetic field with the working principle of time grating sensor,the new structure of angular displacement sensor and the linear displacement sensor are presented.The working principle of the angular displacement sensor and the linear displacement sensor are analyzed by the magnetic circuit theory,and the analysis shows that the two new sensors structure are feasible.(3)The simulation model of two sensors were built and simulated by the simulation software Ansoft Maxwell 16.Simulation results show that the relations between the displacement to be measured and outputs of sensors agree with the working principle of sensor,so the structures of two new sensors are verified by the simulation.(4)Electrical system,acquisition system and experimental platforms are constructed.The electrical system including hardware circuit system and software system,not only provides the excitation signal for the sensor prototype,but also transforms the output signal of the sensors to the angular displacement or the linear displacement information.The experimental platforms include the experimental platforms for angular displacement and linear displacement sensors,which provide experimental conditions for the installation and test of the new sensor.(5)According to the processing requirements in planar coils of the sensor,PCB(Printed Circuit Board)technology was used to make the time grating sensor prototype.The performance of the sensors has been tested by multiple experiments via different combinations of the sensor prototypes,and experimental results not only show that the structures of two new sensors are feasible,but also improve the original measurement accuracy of the inductive time grating displacement sensor by using the time-varying magnetic field constraint method.In the range of 0°-360°,the original measurement accuracy of the angular displacement sensor prototype is better than ± 16.3?;in the range of 0mm-200 mm,the original measurement accuracy of linear displacement sensor prototype is better than ±7.5?m.In addition,the volume of the sensor is greatly reduced,and the thickness of the sensor prototype achieves 0.8mm.