Research On Dynamic Control For A Free-floating Flexible Dual-arm Space Robotic System

Over the past several years, the research on the flexible dual-arm space robot has attracted much serious attention. Considered the elastic deflection and vibration of flexible manipulators, and the situation of modeling uncertainties and external disturbances, the positioning and tracking performance of flexible robots will tend to be degraded. In this thesis, the vibration control and robust control of free floating flexible dual-arm space robots are dealt with, and plenty of simulation tests are conducted to verify the effectiveness of the proposed methods.Firstly, on the basis of the assumed modes method, Lagrange principle and momentum conservation, the dynamic modeling of a free-floating flexible dual-arm space robot is derived, and in the presence of unwanted parametric and modeling uncertainties, the trajectory tracking has been performed by the computed torque method. After that, a mixed approach by robust tracking control, based on the second method of Lyapunov, using simple quantitative bounds on the model uncertainties, and optimal control is developed for reducing the elastic deflection and vibration of flexible manipulators in the trajectory tracking phase, and some simulation results are conducted to verify the effectiveness of the proposed methods.Secondly, the dynamic modeling of the free-floating flexible dual-arm space robot holding a rigid payload is derived. And the trajectory tracking is performed via a hybrid control of adaptive fuzzy controller and model controller. This method is used to overcome the modeling error and disturbance, and the vibration suppression is also very good.Thirdly, a slow subsystem and a fast subsystem are separated based on the singular perturbation method because of the flexible vibration, and the combined control methods are adopted in each system respectively to track the expected trajectory perfectly and suppresse the flexible vibration effectively, even though with uncertainty in model parameters and external disturbances.Finally, two visual simulation platforms using MATLAB and OpenGL are constructed separately for describing the visual movement of a free-floating flexible dual-arm space robot, and some simulation results are conducted to verify the effectiveness of the platforms.