The Dynamic Analysis And Control Of 6-DOF Space Flexible Manipulator

In the 21st century, with the rapid development of aerospace industry and the deepening of space exploration, more and more future space missions, such as the construction of the space station, space equipment maintenance, and other scientific experiments need to be finished, but it is still hard to be completed all by astronaut. Space manipulator has the capability of adapting space environment, so it is significant to complete some tasks using space manipulator, and it has become an important research direction in space technology field. This paper come from the Ministry of Research Science and Technology major projects "space flexible robot dynamics/control coupling system research" , Based on this project, this paper mainly focus on the large flexible space manipulator dynamics modeling theory and control strategy research, the paper's main work are as follows:Firstly, in this paper dynamic model method of flexible manipulator is firstly researched. For designed 6-DOF space flexible manipulator, the flexibility of links is described by assumed modes method and the dynamic model of space flexible manipulator is derived using Kane approach. The flexibility-damping boundary conditions of links is given when the Joints flexible constraint of flexible manipulator is analyzed. The result of the numeric simulation shows dynamic of flexible manipulator.Secondly, in order to verify the flexible manipulator dynamics such as natural frequencies, in finite element environment, transient response analysis and frequency response analysis is done. The dynamic is verified by modal analysis experiment.Thirdly, for the control task of space flexible manipulator, the dynamic system of flexible manipulator is decomposed into slow-changing subsystem and fast-changing subsystem based on singular perturbation theory. The composite control strategy is derived to achieve accurate trajectory tracking and effective vibration suppression. Slow-changing subsystem uses fuzzy sliding model control to improve robustness of rigid movement of manipulator. Fast-changing subsystem uses PD control to suppress vibration. Simulation results shows the proposed method not only accurately and fast track the flexible manipulator locus, but also can effectively damp the elastic vibration.Finally, to validate the modeling and control strategy, a experiment platform with two-DOF flexible manipulator is established.