Position-Based Visual Servo Control for Robotic Manipulation of Space Structures

Deployable space structures and on-orbit assembly are effective methods to build large spacecraft. However, limited by the launcher capacity, the former way is difficult to transport large-scale structures in one launch. While the on-orbit assembly is a feasible option for constructing ultra-large space structures in the future, and the robotic assembly of orbital structures is becoming a focus of orbital operations benefiting from its higher suitability, greater operational range and lower costs. It has always been a challenging and high-precision orbital manipulation task for space robots to grasp and assemble space structure modules. This paper presents a robot manipulation strategy based on visual servo to address the space structure assembly in real time. A position-based visual servo control law is designed using Aruco markers, and deployed experimentally according to the manipulation strategy. The experiment is carried out to grasp and assembly a floating truss structure to a fixed one by a UR5 robot with an eye-in-hand camera. The experimental results demonstrate the effectiveness of the proposed visual servo-based space assembly strategy.