Capture Mechanism Design And Experimental Research For Non-cooperative Spacecraft

In recent years,the number of satellites launched by various countries has increased year by year,and space accidents have produced many fault satellites and space debris,and the orbital resources near the Earth are dwindling.For the sustainable development of space activities,many countries in the world have begun to develop on-orbit service technologies.The autonomous capture technology to the non-cooperative spacecraft is the premise and key to carry out the on-orbit service.This thesis investigates the capture mission in on-orbit services.A non-cooperative spacecraft capture mechanism with simple structure,high connection stiffness,strong binding force,short capture time and large tolerance is designed.The experiments are carried out to verify the effectiveness of the design.Firstly,the motion state of the fault spacecraft is analyzed with reference to the motion form of the spin spacecraft.The Launch Adapter Ring(LAR)is selected as the capture position and the initial conditions are analyzed to extracted the technical indicators.According to the technical requirements,the two-finger structure is designed.The target is captured by enveloping capture,and the overall scheme is studied and the capture process is designed.The detailed structural design of the capture mechanism is carried out,including capture fingers,drive and transmission mechanism,locking mechanism,sensor and supporting structure.The main components are checked using finite element analysis software.Secondly,kinematics and dynamics analysis of the capture mechanism.Establish a mathematical model to the capture finger,analyze its motion form,and use the DH method to calculate the envelope space of the finger.Analyze the transmission relationship between the input torque of the motor and the binding force of the finger end,and clarify the binding force of the finger at different positions.The dynamic analysis of the capture mechanism is carried out to establish the relationship between the kinematics parameters of the mechanism and the force.The tolerance of the capture mechanism is analyzed to determine the influence of different posture deviations on the envelop size.The closing time and locking time of the capture mechanism are calculatedThen,the capture mechanism is simulated and analyzed.By comparing the Adams simulation results with the theoretical calculation results,the correctness of the structural design and kinematics model is verified.The capture process is simulated by the joint control of MATLAB and Adams,and the capture process of ideal state and limit state is analyzed respectively.The simulation results prove that the capture mechanism can successfully complete the capture operation and the structural design meets the capture tolerance index and the capture time.Finally,the prototype performance test and comprehensive capture experimental research are carried out.Before the assembly,the performance of the key components is tested to ensure the smooth progress of the subsequent tests.The test platform is built to test the performance of the capture mechanism prototype.The test results showed that all aspects of the prototype meet the design specifications.The ground capture experimental platform is built.The prototype is loaded on the end of Kuka robot arm,and the three-dimensional space simulation capture experiment is carried out with the air floating platform.The experiment proves that the capture mechanism developed in this paper can stably complete the capture and release operations,which meets the requirements of capture mission.