Study On Series-parallel Space Truss Mechanism Based On Metamorphic Joint

In recent years,along with the development of science and technology,more and more artificial satellites in space,such as communication satellites,meteorological satellites,and navigation satellites,have provided a lot of convenience for human activities such as production and life.However,at the same time,a large amount of space junk is generated,so the recycling of used satellites is very important.The conventional parallel mechanism requires three drive motors to achieve three-direction motion,which has the problems of high quality and high cost.In this paper,a metamorphic parallel mechanism composed of a metamorphic joint and a parallel mechanism is proposed.The metamorphic parallel mechanism is connected in series to form a series-parallel space truss mechanism.Compared with the traditional series-parallel mechanism,the metamorphic series-parallel space truss mechanism use fewer drive motors and have more space for movement.The endparallel space truss mechanism is equipped with an end effector,such as a drill bit,a probe or a clamp,to perform observation and operation tasks.The assembly of multiple series-parallel space truss mechanisms can be used for space capture,so the research on space truss mechanism is of great significance.In the second chapter of this paper,the metamorphic parallel mechanism is designed in detail,and the degree of freedom of the metamorphic parallel mechanism is analyzed.The structure is designed in detail,the function of the metamorphic parallel mechanism in different directions is verified by experiments.In the third chapter,the motion space of the metamorphic parallel mechanism is solved,and the influence of the rod length on the motion space of the metamorphic parallel mechanism is analyzedThe velocity-time curve and acceleration-time curve of the variable parallel mechanism are obtained by deriving the position of the center point of the metamorphic parallel mechanism by a derivation method at a certain rotational speed of two driving motors of a metamorphic parallel mechanism.The system dynamics automatic analysis software ADAMS verifies the correctness of the kinematics analysis results.Using the principle of virtual work,the static analysis of the state of the metamorphic mechanism degree of freedom is 1 and 2 respectively.The dynamic analysis of the metamorphic parallel mechanism is carried out by using the Lagrange equation method.The influence of rod thickness on fundamental frequency of metamorphic parallel mechanism is analyzed.In the fourth chapter,three metamorphic parallel mechanisms are connected in series to form a series-parallel space truss mechanism.The motion space of the seriesparallel space truss mechanism is analyzed.The position of the end point of the seriesparallel space truss mechanism is derived to obtain the series-parallel space truss mechanism.Speed-time curve and acceleration-time curve.The statics analysis of the series-parallel space truss mechanism is carried out by using the virtual work principle,and the dynamics analysis of the series-parallel space truss mechanism is carried out by using the D’Alembert principle.The fundamental frequency of the series-parallel space truss mechanism in the unfolded and folded state is analyzed by ANSYS WorkBench to analysis two working conditions.