Study On Key Techniques Of Measuring The Physical Properties Of Simulated Lunar Soil

The temperature and thermal physical property parameters of the lunar surface are two main contents of lunar thermal environment,and the basic boundary condition of the study of thermal evolution model of the lunar interior,and also the essential parameters to interpret the microwave sounding data.In a scientific sense,obtaining real and reliable lunar thermal physical parameters can make us master relatively accurate,reliable and complete thermal environment properties data of the lunar surface,fill the gaps in knowledge of the properties of lunar thermal environment,lay the necessary foundation about thermal environmental awareness for the establishment of lunar base and further research and development;From engineering application point of view,the thermal control design based on simple and rough thermal environment parameters will be difficult to meet the needs of the lunar surface activity detector,further detailed and accurate lunar surface thermal properties data must be obtained.Lunar hardness is the resistance from lunar soil when lunar rover mechanical movement or static loads transfer to the soil.Therefore,it is essential theoretical basis in the future to measure lunar soil the properties on the lunar exploration and lunar base construction.Firstly,this paper studies the measurement principle of earth soil hardness,and finally representative cone index(CI)is selected to measure the lunar hardness,and guide the design of simulated lunar hardness sensor;Simultaneously,the measurement principle of soil thermal properties is studied,and the heat probe method which is more suitable for powder materials is selected,to guide the design of simulated lunar thermal properties sensor.Secondly,under the guidance of the above measurement theory,the research and design of the front-end structure of the hardness sensor and the thermal properties measuring sensor,and the embedded software and hardware system are carried out.Hardness probe is designed,including the design of the elastomer and the selection of the strain,paste and protection;the front-end of thermal properties sensor is designed,including heater design,probe jacket design and temperature measurement element selection;Embedded system is designed,including the data acquisition circuit,the main control circuit and multi-task management system based on the ?C/OS-?.Thirdly,dynamic limiter amplitude and mean filter is designed by improving the common digital filter algorithm for temperature data and hardness data in this paper,and the feasibility of the filter is verified by Matlab simulation.Then,the hardness data is obtained by the output data of strain gauge,the particle swarm optimization(PSO)algorithm is improved for thermal properties inversion to improve the efficiency and applicability of the algorithm,and the feasibility of the improved PSO algorithm is verified by Matlab simulation.Finally,the hardware and software modules of sensor designed are calibrated separately and the whole standardize is carried out,and the results of the experimental data of hardness sensor and the data of thermal properties inversion of thermal properties sensor are given.