Formulation and control of space-based flexible robots with slewing-deployable links

The present study deals with a space-based variable geometry mobile manipulator with an arbitrary number of modules, each with two flexible links: one of them free to slew (revolute joint); and the other deployable (prismatic joint). The versatile manipulator has several attractive features: favorable obstacle avoidance, absence of singular configurations, reduced inertia coupling, relatively simpler inverse kinematics as well as governing equations of motion, to mention a few. To begin with, derivation of the governing equations of motion, using the Lagrangian procedure, is explained. As can be expected, the recursive equations are highly nonlinear, nonautonomous and coupled. This is followed by the development of a numerical algorithm leading to the solution for the inverse kinematics. Finally, some typical simulation results for trajectory control of the end-effector using the resolved acceleration approach are presented. They clearly emphasize importance of the control strategy based on the flexible manipulator model.