Dynamic Modeling And Compliance Control Of Space Robot Capturing Non-cooperative Objects

As the science and technology developing and the resources reducing,outer space is more and more important to our mankind.Along coming with all the progress and achievements are problems of space trash and aircraft service.To meet the requirements of the project founded by National Natural Science Foundation “Research on dynamic stiffness recognizing and compliance strategy during capturing non-cooperative space objects”,the thesis focuses on the development of space robot and the compliance control strategy used to stabilize the contact force during capture process.Aiming at the needs and requirements of the space robot used in capture process,a brand new serial-parallel hybrid robot is well designed to obtain both control stability and large working space.A serial equalizing method is proposed to solve the kinematic problem.Workspace analysis shows the robot is of a large and adjustable dexterous workspace.To solve the dynamic problem of the robot capturing non-cooperative objects,a payload equalizing method is proposed.Considering the serial part of the robot as payload of the parallel part,an iterative dynamic algorithm is developed by applying the Newton-Euler method.To stabilize the contact force between space robot and target satellite,a compliance control strategy based on the admittance control is proposed.It also includes a motion predictor,a dynamic feedforward controller and a motion planner.To verify the control strategy,several simulation and experiments is carried out,which including a digital simulation model in Simulink,a HIL testbed in Simulink-UG virtual environment and a solid full-physical simulation testbed.It is proved through all the simulation and experiments that the contact force is well stabilized by using the compliance controller.