Restoration Research For The Profile Design Defects And Resonance Design Defects In Satellite Docking Mechanism

The docking mechanism is a key component of interactive satellite docking.One of its task is to ensure the fast docking and reliable connection between the service satellite and the target satellite,another of its task is to ensure stable and reliable separation after the completion of in-orbit service operation.Contour design defects in the docking mechanism will result in greater docking collision force,resonance design defects in the docking mechanism during satellite lift-off will result in greater stress and amplitude,contour design defect and resonance design defect in the docking mechanism may lead to failure of the docking mission.In this paper,a three claw type cone rod docking mechanism which combines advantages of three claw type docking mechanism with advantages of cone rod type docking mechanism,is designed.The collision force of docking mechanism and active natural vibration characteristics of side impact bar are analyzed,contour design defects and resonance design defects in the docking mechanism are identified and repaired.A three class claw type cone pole light docking mechanism is designed,the docking mechanism is mainly composed of conical rod components and three sets of fetching components,which distributes homogeneously and symmetrically.Conical rod component is responsible for implementing first satellite docking capture and three sets of fetching components are responsible for implementing precise satellite docking,the docking mechanism possesses such advantages as simple structure,light quality,high reliability,etc.It can meet the requirements of small and medium-sized satellite docking mission.Based on the theory of adhesive friction,the dry friction of the docking mechanism is transformed into the furrow force and adhesive force between the rough peaks of the object surface,the formulas for solving the friction coefficient of the docking mechanism are derived.The roughness peak on the hard metal surface is equivalent to the rigid conical roughness peak and the height of the rigid conical roughness peak is normally distributed.The furrowing force between the roughness peaks on the contact surface is calculated by referring to the contact factor,the adhesion between the contact surfaces was analyzed by using the "pebble" model.The influences of the relative velocity of the object,the conical half angle of the rigid conical rough peak and the curvature radius of the curved surface on the friction effect are studied by using MATLAB software as simulation examples.The rationality and correctness of the formulas for solving the friction coefficient of the docking mechanism are verified.Combined the friction coefficient solution formulas and Hertz theory,the impact load model considering the friction effect for the docking mechanism is established.Based on the impact load model,particle swarm optimization(PSO)algorithm is used to optimize the ball head lever and size parameters of the docking cone,the optimized micro structure of the surface of the simulation diagram is obtained,the impact load of docking mechanism is reduced,the contour design defect in the docking mechanism is repaired.The vibration characteristics of the ladder impact bar are studied,the formulas for calculating the natural frequency of the ladder impact bar are derived.The natural frequency of the ladder impact bar is improved by replacing the traditional uniform cross section impact bar with the ladder impact rod,vibration problems of ladder impact rod is equivalent to that of ladder cantilever beam,based on the continuity of Euler-Bernoulli beam theory and beam properties,vibration problem of ladder cantilever beam is analyzed.By way of adopting the idea of segmentation,equivalent treatment for impact rod ball head and utilizing boundary conditions of ladder cantilever beam,calculating formulas for the cantilever beam vibration frequency are deduced.According to natural frequency calculating formulas of the ladder impact rod,under the condition of equal quality,genetic algorithm is used to optimize the size of ladder impact bar,the first three order vibration modes of the ladder impact rod are obtained,its natural frequency is improved.The finite element simulation is used to verify the correctness of the natural frequency calculation formula for ladder impact rod,ABAQUS is used to simulate the effect of random vibration excitation on the ladder impact bar during lift-off.The simulation results show that the resonance phenomenon occurs before the defect of resonance design is repaired,greater effective amplitude and effective stress appeared.After the defect of resonance design is repaired,the resonance phenomenon disappears,the effective amplitude and effective stress are reduced greatly.