Research On The Key Technology Of The Transfer Mechanism Efficiency Test Bench

As Earth’s only natural satellite, the exploration of the Moon has greatsignificance in technological, economic, military, political and other aspects.China’s "Chang E" lunar exploration project is divided into three sections, namelyencircling, landing and return. The "Chang E" lunar exploration project Ⅲ that isbeing prophetically demonstrated will use the sample container transfer mechanismwhose function is to transfer the lunar soil sample container from the lunar-orbitingspacecraft to the earth-orbiting spacecraft. Because of the limited movement space,stringent weight requirements and large temperature span, these factors haveadverse effects on the structural design and motional reliability. Therefore, there isgreat need to develop the transfer mechanism efficiency test bench to doground-testing experiments, detecting the transfer efficiency to verify the reliabilityof the transfer mechanism.The transfer mechanism efficiency test bench is a kind of load simulation testbench that can simulate high and low temperatures. Based on the comprehensiveanalysis of the characteristics of load simulation test bench in China and abroad, thepaper presented an internal adjustment efficiency test bench. The test bench insistsof two sections, namely drive component and load component. More specifically,drive component uses servo motor as the power source, screw nut as thetransmission rig, tension and compression force sensor and encoder as the inputpower detecting device; load component uses servo motor as the load simulator,linear motion units as the linear guide rig, micro-displacement platform as thedisplacement adjustment rig, tension force sensor and encoder as the output powerdetecting device. Finally, the output power divided by the input power equals theefficiency of the transfer mechanism. Based on the overall design, the responseanalysis, the resistance setting accuracy analysis and the mechanical systemintegrated error analysis to the load simulation system were done, layingfoundations for the development of the test bench.In order to ensure that the heat conduction and sealing failure do not affect theexternal motor, the paper conducted research on the heat conducting, heatdissipating and interface sealing of the screw shaft assembly. Building the initialscrew shaft model and using SPSS statistical software for correlation analysis, thepaper identified the most important parameters from a number of factors that affectthe heat conduction. Then the paper established the screw shaft assembly model toanalyze the influence that the most important parameters have on heat conducting. Based on the theory of forced convection to a circular cylinder in crossflow and theCFX fluid-thermal coupling simulation, the relationship between the gas flow rateand the cooling effect was analyzed quantificationally in order to obtain the bestcooling gas flow rate. Building the gas leakage model of the screw shaft assembly,the paper quantificationally analyzed the influence that the leakage gaps andleakage gas flow rate have on the sealing effect.In order to guarantee the sensor, which is inside the high-low temperaturechamber, can work normally in-60~80℃, the paper developed temperature controlrig of sensor used in low temperature. Based on the unsteady heat conduction theory,the relationship between the temperature of the sensor and the outer surface and theheating time was analyzed in order to determine the heating plate power and thethickness of insulation materials; Finally, the experiments on temperature controlrig of sensor were done in order to verify the accuracy of simulation and reliabilityof the rig itself.