SLEWING DYNAMICS AND CONTROL OF THE SPACE STATION-BASED MOBILE SERVICING SYSTEM

A relatively general Lagrangian formulation for studying the non-linea r dynamics and control interconnected flexible members in a tree-type topology is developed. Versatility of the formulation is illustrated t hrough a dynamical study of the Space Station-based two-link mobile se rvicing system (MSS). The performance of the MSS undergoing inplane ac id out-of-plane slewing maneuvers is compared. Results indicate that, in absence of control, the maneuvers induce undesirable librational mo tion of the Space Station as well as vibration of the links. Non-linea r control based on the feedback linearization technique (FLT), appears promising. Quasi-closed loop control (QCLC), a variation of the FLT, is applied to control the libration of the Space Station. Once the att itude of the Space Station is controlled, the performance of the MSS i mproves significantly. For a 5-min maneuver of the MSS, the maximum co ntrol torque required is only 34.5 Nm.