| At present,the docking of spacecraft mainly adopts the traditional "manual-based" assembly mode in our country,which exists many disadvantages,such as the processes are complicated,the measurement accuracy is insufficient,and the assembly efficiency is low.In recent years,because the number of spacecraft missions has continued to increase,so the intensity of work has increased significantly.In order to improve the efficiency,accuracy and consistency of spacecraft assembly,a high-precision flexible docking device is urgently needed.(1)Research on the Mechanism Configuration of the Flexible Docking Device for Cabin.Firstly,the structural characteristics and posture expressions of cabin are analyzed,and the functional requirements for the flexible docking device of the section are obtained.Then,the mechanism of 6-SPS and 4-PPPS commonly used in the spacecraft docking field are analyzed to obtain the advantages and disadvantages.Two improved mechanisms,2-6-SPS and 2-PPPRRR,are proposed.Finally,a comprehensive comparison of the two proposed mechanisms is made,and the mechanism of the 2-PPPRRR-type mechanism as the flexible docking device of the cabin is determined finally.(2)Research on Coordinated Operation of Mechanism Based on Kinematics Analysis Theory of Two Robots.Based on the D-H method and the loop vector method,the mechanism composed of 2-PPPRRR and the docking section is analyzed to obtain the position relationship between cabin and the robot arm joint;The posture adjustment and docking process of the lower section is coordinated by two robots,and the calculation formula of posture adjustment is derived.In order to ensure that the docking process moves smoothly,the trajectory planning of joint motion is made based on the fifth-order polynomial motion trajectory,and the motion simulation is performed with Adams,which verifies that the trajectory planning method meets the design requirements.(3)Structural design and motion characteristics of the flexible docking device of the cabin.The structure and function of each component of the flexible docking device of cabin are designed and explained in detail.Aiming at the problem of kinematic coupling between the X-direction moving joint of the right arm with the Y-direction moving joint or the Z-direction moving joint,a flexible decoupling component is proposed.Aiming at the fact that the free rotation of the joint around the Z axis may reduce the stability of the mechanism,a flexible maintenance component is proposed innovatively.The static and dynamic characteristics of key components are analyzed with ANSYS Workbench,and the deformation of the mechanism under the maximum load condition is obtained.The design accuracy is compared with the design accuracy requirements to determine whether the design accuracy met the requirements.Secondly,through the modal analysis of key components,the natural frequency range between the two connected components is compared,and the anti-resonance performance of the flexible docking device of the cabin section is summarized.(4)Experimental study on automatic docking of cabin.The digital flexible assembly system of cabin was debugged.Under the conditions of ensuring the normal operation of each subsystem,the cabin docking test is performed.In terms of coaxiality,the final deviation of the translational axis of each cabin is ≤0.3mm,the rotation angle residual is￡0.1°,Yaw and pitch angle deviation is ￡ 0.03°.Validated the rationality and efficiency of the attitude adjustment and docking device design of the cabin section. |
