Dynamic Modeling And Analysis Of Space Flexible Manipulator

With the rapid development of space technology and robot technology, theflexible manipulator are widely used in the field of aerospace,due to its lightquality, high speed, and low energy consumption.However, it is difficulty to controlthe vibration of flexible manipulator owing to the joint flexiblity and flexible-linkelastic deformation coupling.It is great significance that establish accurate andpractical dynamic model for the trajectory tracking and active vibration control offlexible manipulator. To solve thisproblem,in this paper, the dynamic problems offlexible manipulator is atudied, the main content is as follows:1、The kinematics and dynamics modeling of flexible multibody chain systemis briefly introduced. By assumption modal method combined with thoughLagrange equations and global modal method combined with Hamilton principle,dynamics equation of flexible manipulator are establish.2、 Based on the analysis of the flexible manipulator that consists offlexible-link and flexible-joint, the global mode shapes of the flexible manipulator ispresented. The coupling movement differential equation of flexible-link andflexible-joint are derived by using the Hamilton principle. Through their forceboundary and matching conditions, the undamped natural frequencies and modeshapes of the linearized model of the flexible manipulator are determined, andorthogonality relations of the mode shapes are established. The undamped globalmode shapes are used to discretize the coupling movement differential equation offlexible-link and flexible-joint. The simulation results show that the joint flexibilityand the elastic deformation of flexible-link can have a significant effect on thesystem frequencies. A comparison between the results obtained by the proposedmethod and those from assume mode method is given to illustrate the validity of ourapproach. According to the global modal,it can reflect the inherent characteristics ofthe system.And its solving method is more used,which borrowed from the traditionalmode. Finally,response history simulation is taken to study,and the deformationof joints and the end of link elastic vibration displacement is analyzed.3、Dynamic model of two-link flexible manipulator with flexible joints isestablished by using global modal method combined with Hamilton principle. Firstof all, the complex boundary conditions are analyzed. The partial differentialequations of motion for a two-link flexible manipulator are derived, along with theirboundary conditions by using the Hamilton principle. Combining the governingequations of flexible link and flexible joint, the undamped natural frequencies andmode shapes of the linearized model of the two-link flexible manipulator are determined. Through the frequency equation presented in this article, a study on thevariation of natural frequencies with the time-varying elbow angles is performedusing a two-link flexible manipulator with a set of typical geometrical parametersand material constants. Thus we can predict the tendency and range of the systemnatural frequency.