Analysis And Design Of Inductive Displacement Sensors With Wide Dynamic Range And High Bandwidth

The ultra-high speed of large aerospace vehicles and the clustering and low cost of conventional vehicles are two important development directions of precision guidance equipment.Both of them put forward extremely stringent design requirements for its precision guidance equipment.The former must solve the bottleneck problem that the imaging detector can not image clearly under the condition of strong vibration and high overload;The latter needs to innovate the electromechanical configuration of the seeker to minimize the volume,weight,power consumption and cost of the servo mechanism.High speed and high precision beam control devices based on micro nano positioning technology,such as fast mirror and micro scanning mechanism,provide a technical solution to solve the above problems,and are the research hotspot in the field of new imaging seeker.Micro displacement sensor is the core functional device of this kind of control device.Its dynamic range,test bandwidth and measurement accuracy in array layout directly determine the performance index of high-speed and high-precision beam control device.At the same time,it has small volume(mm size),large dynamic range(submicron resolution,mm range,dynamic range better than 10000:1),high bandwidth(test bandwidth better than 1 k Hz)Ultra precision micro displacement sensor with high stability and reliability in harsh working environment is an urgent motion sensor to realize the electromechanical design of high-speed and high-precision beam control device.The measurement principle of inductive sensor still has high sensitivity in small size,and is not sensitive to the change of environmental conditions.It can achieve nano resolution in small range and low-speed measurement.However,the existing design models,design methods and products do not meet the index requirements in range and bandwidth.In order to increase the dynamic range of inductive sensor and improve its test bandwidth,this paper deeply analyzes and discusses the analysis model,material structure characteristics,probe design method and signal processing method of inductive sensor:1.Based on the traditional inductance calculation theory,finite element analysis and experiment,a leakage inductance model is proposed to reveal the functional relationship between leakage inductance and core size,Based on the leakage inductance model,the relationship equation between sensitivity,initial gap and core size is further deduced,and the relationship between performance and range and structural size parameters is clarified,which provides an important basis for the structural size design and performance prediction of inductive sensor.2.The magnetoelectric conversion characteristics of differential inductance sensor under AC bridge measurement circuit are analyzed,and a signal processing circuit of differential inductance sensor based on AC bridge and all digital phase-locked amplification is designed;The displacement measurement system of the differential inductance sensor is designed and the performance test experiment is carried out.When the range is±0.5 mm and the bandwidth is 1 k Hz,the RMS resolution of the differential inductance sensor is 3.5 nm and the dynamic range is better than 2.8×10~6:1.3.Through further analysis,the optimization method of excitation frequency and the basis for material improvement are put forward in order to further improve the performance of the sensor.4.On the basis of the above research,combined with the application practice,the error characteristics of multi degree of freedom micro displacement measurement with multi probe array layout are discussed,and the cross coupling problems in multi degree of freedom translational displacement measurement and multi degree of freedom angular displacement measurement are studied.