Research On Dynamic Modeling And Vibration Suppression Of A Flexible Redundant Space Manipulator

With the development of space exploration, the manipulators that service for spacestation have to be much larger size and much faster operating speed, but the large massand slow operating speed become obstacles which make conventional manipulator bleakfuture. To overcome these obstacles, people put their focus on flexible manipulator forits characteristic of lightweight. However, the flexible manipulator always results invibration during mission and how to reduce this vibration has been researched as apopular topic. Taken this as background, this thesis will focus on solving somemeaningful things, which include dynamics modeling of flexible space manipulator,analysis of dynamic characteristic for flexible space manipulator and suppressingvibration which occur in completing mission.Flexible space manipulator is a complex dynamic system with characteristics ofhigh level, nonlinear and strong coupling. For the purpose of developing precisealgorithm for control and trajectory planning, an accurate dynamic model is required.First, the dynamic equation of flexible space manipulator is accomplished by employingthe Lagrangian multiplier method, then derivate the constraint equation in velocity levelaccording to the type and motion state between two contiguous arms last put thedynamic equation and constraint equation together, the Differential Algebraic Equationthat describes flexible space manipulator can be got. To verify the dynamic model above,a C program and a virtual prototype model in dynamic analysis software ADAMS areconstructed, comparing outputs of two models respectively with the same inputs andresults provide correctness of dynamic model.The vibration of flexible manipulator is a result caused by many different flexiblefactors, in order to analysis the effect of a factor caused alone, dynamic characteristicsof flexible manipulator with different Yung’s modulus of elasticity, material dampingand flexible joints are consideration separately. Then based on the rotor-beam elementwhich contains a flexible joint and a flexible arm, the dynamic characteristics caused bymany factors at the same time are consideration.Flexible space manipulator will generate vibration during mission as well as aftermission and this vibration will affect positional accuracy of endpoint. In order to reducethe vibration into a range that can be allowed, this article provides a method whichcombines the self-motion characteristic of redundant manipulator and Particle SwarmOptimization Algorithm to suppress the vibration of flexible manipulator. Searching forthe joint space solution that can make the vibration meet required precision in theself-motion space which is a region that the minimal norm solution as the center. Finally, simulation studies have shown that the method is feasible and effective.