Research On Modeling Of Space Flexible Manipulator Based On Shape Memory Alloy

With the development of space technology in China,more and more operations performed by astronauts are required,which are accompanied by great risks,especially the extravehicular activities.It is a safer and more economical way to use space manipulator to cooperate with astronauts or take over the extravehicular operations.Space manipulator is easy to produce deformation and vibration when it is running,which is difficult to decay.The study of dynamic characteristics and vibration control of space manipulator is the premise and guarantee of the stability of manipulator.the flexibility of the beam and the joint should be studied together in the analysis of the space manipulator.As a new type of smart materials,shape memory alloy(SMA)has high recoverable strain in hyperelastic state and large energy consumption during loading and unloading cycle,which can be used to suppress the vibration of the space manipulator.In this paper,the dynamic modeling of flexible joint-beam space manipulator with shape memory alloy which is used to reduce vibration is studied:1.This paper studies the dynamics modeling of space flexible manipulator in noninertial system.The dynamics model of a single flexible manipulator attached to a central spacecraft is built by the first-order approximation coupling model.Numerical simulations are carried out under the condition that the large-scale movement of the central spacecraft is the fixed-axis rotation,which verifies the reasonableness of the modeling method.2.The coupling dynamics model of the system consisting of the center spacecraft,the flexible joint and the flexible arm is established.The effects of coupling deformation and the nonlinearity of the inertial force on numerical simulation are discussed.Based on the simulation results,the coupling dynamics model is reasonably simplified.The effects of flexibility of the joint and rotation speed of the center spacecraft on the deformation and vibration of manipulator is studied.It is proved that the effects of the flexibility of the joint and the flexibility of the arm can not be neglected in the dynamic analysis of space flexible arm.3.The hyperelasticity model of shape memory alloy is introduced into the the dynamic model of flexible joint-flexible arm space manipulator,and two kinds of passive vibration suppression dynamic models using shape memory alloy are established.The dynamic numerical simulation of passive vibration suppression of flexible joint-beam manipulator using shape memory alloy wire was carried out,which is a preliminary identification of the damping effect.