| The traditional peripheral and conical bar docking is a mature mechanism docking mode in the aerospace field,which realizes the docking of active and passive structures by attitude adjustment,but its structural size is too large to be suitable for the docking of current samplers.In order to adapt to the working mode and life of planetary sampling,a planetary sampling automatic docking mechanism is designed in this thesis,which can realize tolerance and weak collision docking,and the sampling tube can be replaced repeatedly.Through the detailed design of the structure of the main passive end,the failure mode and influence of the structure,kinematics and dynamic reliability are studied.First of all,on the basis of in-depth understanding of the docking technology at home and abroad,a variety of sampling docking schemes are put forward,and finally the locking docking structure is optimized.the innovation lies in the docking locking while transferring the power source of the active end to the passive sampling unit.to realize the complex requirements of three kinds of sequential actions of one power source,at the same time,the designed vortex disk and claw can put forward the work of the sampling unit as a whole,and recover and lock after the empty tube.Secondly,the docking and working fault modes of the mechanism are analyzed,the coordination relations of different materials and structures are obtained according to the working environment of the mechanism,the FMEA worksheet of the unit is listed,the fault tree model of the docking mechanism is established,the bottom events that may lead to the failure are found step by step,the mathematical model of the reliability of the docking system is established,the reliability of the mechanism under extreme load is obtained,and the fault tree is analyzed qualitatively and quantitatively.The kinematics reliability analysis of the mechanism is carried out,the motion equation of the active end is obtained by establishing the docking coordinate system,the position and attitude deviation of the mechanism is analyzed by coordinate transformation matrix,and the key interface and contact are designed and analyzed.the velocity,radial displacement,attitude angle and angular velocity are taken as variable parameters to find the feasible region and sensitivity influence of the docking process.Finally,according to the docking feasible region,the docking reliability under ultimate working conditions is calculated.The dynamic model of the mechanism docking collision process is established,and the rationality of the model is preliminarily verified.The locking force and the reliability of the locking process are calculated,and the docking tolerance of different initial positions is analyzed by ADAMS software.The results show that the docking reliability requirements are met under the tolerance condition,and the theoretical calculation is verified by the simulation of the driving shaft and locking force.Finally,the driving performance simulation and driving performance test of the sampling tube are compared. |
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