Research On Piezoelectric Six-dimensional Force Sensor In Small Working Space

The precision machining of the rocket fuel tank grid is directly related to the safety and economy of rocket launching.Mirror milling machining method based on integration of surveying and machining with its high efficiency,general-purpose strong,high precision has been an effective way to solve the problem of large-scale thin-walled parts processing.To ensure the processing accuracy of mirror milling,we should acquire the multi-dimensional force,torque information of the support end and the small changes of the support force accurately to adjust the position of the support end and the size of the support force in real time.The stiffness compensation is provided for local machining areas.Obviously,the real-time measurement of the support force signal is an important guarantee for the reliable operation of the raster mirror processing and equipment.In addition,the support end requires a high degree of integration,and the force sensor unit is confined within a narrow measurement space of ?17mm.The support force signal is obtained by the force sensor.Therefore,the development of multi-dimensional force sensor in small working space for the support force measurement and its precise calibration is the foundation to ensure the accuracy of bulkhead grid processing.In this paper,the support force signal measurement is the research object.For the support force signal measurement space is limited,multi-dimensional,low resolution of the test,the support force test difficult is analysis from the test principle,theoretical analysis,simulation and experimental.The corresponding solution is proposed and the small multi-dimensional high sensitivity sensor for the support force measurement is developed.Firstly,the force of the support end is analyzed,and the difficulty of the force signal is put forward.The correspondence between the induced charge and the six-dimensional stress is obtained by using the stress distribution law of the piezoelectric wafer under the action of six-dimensional force,and the combination of the crystal and the electrode is obtained.The measurement of the six-dimensional support force in the small space is realized.Next,the structure of the crystal group and the shell is designed.The preload form of the force sensor in the small space is determined.The mechanical model of the sensor in the preload state is established,and the transmission process of the analysis force on the sensor is established.The allowable range of the stiffness of the preloading member under different ranges is obtained.The simulation is carried out by ANSYS Workbench software,and the modal and static structure analysis of the sensing are carried out.The results meet the measurement requirements of the support force in the mirror milling process.According to the influence factors of the resolution of the test system,the components of the measuring circuit are selected reasonably.Finally the force test system is completed.Finally,the calibration of the piezoelectric power sensor was carried out.The static and dynamic calibration of the force sensor is got.The influence factors of the static calibration index are analyzed,and the influence of the partial load on the inter-diffusion is focal point.A method to measure the degree of deviation of the loading point is proposed.In order to overcome the inevitability of mechanical connection,we propose an output proportional normalization method to overcome the effect of partial load on the normalization coefficient,and reduce the maximum interference by less than 5%.After that the force sensor of the resolution test experiment is carried out and the experimental results show that the developed piezoelectric multi-dimensional force sensor can meet the requirement of support force measurement.