Analysis And Experimental Research Of The Flexible Base For The Ground Expenriment Of The Space Station Micro-manipulator

With the continuous development of space industry, astronauts will be required to complete more and more space missions. Space manipulators are usually used to assist astronauts to complete the operation task. In order to increase the working space of space manipulators and meet the diversified requirements of tasks, separated time independent working mode of the macro-micro manipulators series is adopted. Macro manipulator as the base of the micro manipulator will take the micro manipulator to the desired area. Then the micro manipulator will complete the final operation of the task. For different tasks, the macro manipulator will have the corresponding configuration and stiffness characteristics. In this paper, a kind of flexible base of ground experiment for simulating the stiffness characteristics of macro manipulator is developed.First of all, the stiffness characteristic analysis of the macro manipulator is carried out. The stiffness curves with the elbow joint angle are gotten and compared in the case of ignoring and considering the flexibility of links. It is found that the flexibility of links can’t be ignored. Under the condition of considering the flexibility of links, the stiffness characteristic of the macro manipulator is analyzed. The spatial stiffness matrix is obtained and converted to the planar stiffness matrix. Based on this, the design index of variable stiffness flexible base for ground experiment is presented.Secondly, a flexible base is designed, which is based on the lever variation principle, the principle of gear and rack, and the speed growth principle of steel belt wheel mechanical. The adjustable stiffness of flexible base is realized through two different forms of lever mechanism. The coupling between different degrees of freedom is realized through the rack and gear. The function of stroke linear amplification is realized through the steel belt wheel mechanical. In order to facilitate the design of mechanism, the concept of equivale nt stiffness is put forward. The simulation is carried out by Adams. The strength analysis of the key components is carried out by using Ansys to ensure the reliability of the design.Then, the equivalent stiffness of the four assembly positions of the fle xible base is modeled and analyzed. The relationships between the variable parameters of the flexible base and the stiffness of variable stiffness modules are obtained. The source of the equivalent stiffness error of flexible base is analyzed, and the sele ction process of the installation position of the flexible base is provided. The friction force in the flexible base is modeled and analyzed, and the compensation strategy is put forward. Dynamic modeling analysis and modal analysis are carried out to obtain the dynamic characteristics of the flexible base.Finally, the experimental platform of flexible base is built based on the space manipulator. The static stiffness characteristics and dynamic characteristics of the flexible base are tested. The validity and correctness of the flexible base are verified.