Assembly Strategy for Modular Components Using a Dual-Arm Space Robot with Flexible Appendages

Space robotic systems tend to be more flexible and equipped with some appendages, such as solar panels and communication antennas. The inevitable vibration in the flexible appendage will occur during space missions, and it in turn affects the attitude of the rigid base due to coupling dynamics. This study develops an assembly scheme for a dual-arm space robot with flexible appendages to assemble two modular components and to minimize the disturbance force caused by the manipulators to the base and flexible appendages. The assembly strategy consists of two stages, a preassembly stage which transports the two components to desired relative states, and a trajectory tracking stage to achieve the final assembly. In the first stage, based on a relative Jacobian matrix in the base frame, an optimal objective function is formulated in terms of the relative position and attitude errors between the two components. Thereby, more freedom of manipulators is released for minimizing disturbance forces. Notably, two virtual points are created to describe the relative position between the two components. In the second stage, two components are driven to follow a relative trajectory for the final assembly with an unchanged relative attitude. Finally, numerical simulations are conducted to demonstrate the efficiency of the proposed assembly strategy.