Lunar Surface Sampling Device Mechanism Design And Experimental Analysis

Sampling device is an important part of the interstellar sampling task which requestscharacteristics such as light structure, high efficiency and low power consumption. Theresearch on institutions and its sample mechanical characteristics of sampling device plays avital role in improving the reliability of space sampling, improving the single sampling rateand shortening sampling task time window. The study of spatial sampling device givespriority to near-earth asteroid sampling and lunar surface sampling and the majority of spatialsampling task is lunar surface sampling. However, China is still in its infancy stage insampling research and main problems are the single research method, less samplingcharacteristic test, imperfect test method and absence of test approach. On the basis ofsummarizing predecessors’ works,this paper designs and produces backhoe type moon surfacesampling device and its performance test system. It also apply this system to the study ofsampling device’s performance and function research.Main contents and results are as follows:1. This paper comes up with three different lunar surface sampling devices which makeuse of backhoe, clamshell and rotary excavation. The principle prototype of each one is testedfor sampling function. The results indicate that although they can meet surface samplingrequirements, backhoe sampling device is better than the others in the aspect of sampleperformance indicators and primary packaging container transfer performance metrics. As aresults, backhoe sampling device is further studied in this paper.2. Based on the backhoe sampling principle, this paper designs backhoe lunar surfacesampling device which contains motivation and drive components, bucket and clampingcomponents and angle measurement components. This device is light in quality, simple instructure and low in power consumption. It can fulfill the task of surface sampling, sampletransfer and primary packaging container transfer.3. This paper forecasts and studies excavation force of backhoe lunar surface samplingdevice on the basis of summarizing predecessors’ work. The prediction method used in thispaper is soil cutting model raised by McKyes. Bucket cut soil stress equation is set upaccording to the model while matrix of changing depth of cutting soil is set up by backhoebucket geometric features. At last, predicted results of sampling device excavation forcechanges are calculated which are related to the changes of bucket angle.4. Based on the backhoe lunar surface sampling device, this paper designs samplingdevice performance test system which contains bearing frame, mechanical arm, sixdimensional force transducer and mobile lunar soil box. With the help of this test system,surface sampling of backhoe moon surface sampling device, sample transfer and primarypackaging container transfer is tested. The results indicate that backhoe moon surfacesampling device has good capability of groundbreaking, sampling and container holding.Various performance indexes meet requirements.5.Through analyzing the differences between sampling test results and excavation forceprediction result, excavation force prediction model of backhoe lunar surface sampling deviceis optimized. It comes out that two-dimensional cutting soil model is more suitable for cutting force prediction with a penal bucket type soil cutting tool. According to the optimizationmodel, sensitivity analysis on sampling force of lunar soil density, cohesion and internalfriction angle shows that soil density has the greatest impact on sampling force followed byinternal friction angle and cohesion. It has certain guiding significance to the study ofsampling force of the device.