Modeling and Control of a Hybrid Soft–Rigid Space Manipulator System

Space manipulators are a key enabling technology for future on-orbit servicing and active debris removal missions, yet conventional rigid designs can limit overall system dexterity. This work introduces a novel hybrid soft–rigid space manipulator system (HSMS), which integrates a tendon-driven continuum manipulator with a traditional rigid robot. A strain parameterization technique known as geometric variable strain (GVS) is employed to derive a closed-form, minimum-order dynamic model of the HSMS by leveraging the principle of virtual work. Thrusters and variable-speed control moment gyros are incorporated to activate the spacecraft base and enhance the realism of the description. Two inverse-dynamics control designs are then proposed: one to bring the system to rest from a nonzero momentum condition and another one to track a three-dimensional trajectory in the end-effector task space. Extensive numerical simulations validate both the dynamic model and the proposed controllers, demonstrating the potential of the proposed HSMS concept for advanced space-manipulation tasks.