Improved sliding-mode variable structure control of free-floating space-based manipulator to track desired trajectory in workspace

In this paper, the sliding-mode variable structure control problem of a free-floating space-based manipulator system whose base attitude is controlled is studied. With the linear momentum conservation of the system, the kinematics and dynamics of the system are analyzed. It is demonstrated that the dynamic equations and kinematics Jacobian matrix of the system can be linearly dependent on a group of inertial parameters. In order to make the control scheme more effective, an improved sliding-mode variable structure control scheme for space -based manipulator to track desired trajectory in workspace is developed with the results proposed above. The control scheme proposed need not calculate the elements of Centripetal and Coriolis torque vector time and again, by off-line estimating the upper and lower limit of the elements only one time. So It can effectively reduce the calculation time needed by the classical variable structure control scheme during the period of real-time control. A simulation study of two-link planar space-based manipulator system is presented, it is shown that the control scheme proposed is feasible and effective.