Nonlinear Modeling and Dynamic Feedback Control of the Flexible Remote Manipulator System

The paper studies nonlinear dynamics and control of a class of space station based mobile flexible two-link manipulators, normally referred as the Mobile Servicing System (MSS). The governing nonlinear, nonautonomous and coupled equations of motion are described first followed by the modal discretization procedure. A parametric response study suggests situations with unacceptable levels of deflections and accelerations for certain proposed missions, as well as station libration and payload positioning errors. An inverse control technique is proposed to achieve high tracking accuracy of the MSS in presence of maneuver induced disturbances. The control strategy is so designed as to regulate the libration of the Space Station as well as to insure joints tracking of prescribed trajectories while limiting the effect of the structural vibration. Two different control schemes, both based on the feedback linearization technique, are developed and their relative merit assessed.