Hybrid modeling and analysis method for dynamic coupling of space robots

TLDR

The authors propose a hybrid method that resolves linear and angular momentum conservation equations to model and analyze the dynamic coupling of a space robotic system. The method treats base centroid position coupling at the position level and attitude coupling at the velocity level, employing a base centroid virtual manipulator concept to define reachable, attitude‑constrained, and free coupled spaces, decomposing velocity coupling into joint‑to‑base and end‑to‑base rotation and translation components, and using coupled maps to plan trajectories that minimize disturbance under varying loads, positions, and joint configurations. The study reveals that rotation and translation coupling depend on each other, quantifies coupling factors, shows that position‑level coupling eliminates singularities while velocity‑level coupling is modeled separately, and demonstrates the method’s usefulness for designing new manipulators or adapting existing robotic systems.

Abstract

Resolving linear and angular momentum conservation equations in different ways, a hybrid method was proposed to model and analyze the dynamic coupling of a space robotic system. This method dealt with the coupling problems for the base's centroid position at the position level and attitude at the velocity level. Based on the base centroid virtual manipulator concept, the coupled space was addressed to represent the base's centroid position coupling. For different cases, the reachable coupled space, attitude-constrained coupled space, and free coupled space were defined. However, the coupling for the base's velocities was decomposed into joint-to-base rotation, joint-to-base translation, end-to-base rotation, and end-to-base translation coupling types. The dependence of the rotation and translation coupling was revealed, and the coupling factors were determined to measure the coupling degree. Then, the coupling effect for different loads, installation positions, and joint configurations was analyzed. Coupled maps were established to plan the trajectory for minimizing disturbance. Compared with previous works, dynamic coupling at the position level avoids the singularity problem for solving differential equations; at the velocity level, each type of coupling motion was separately modeled and analyzed for different requirements. The proposed method is useful for practical applications, such as designing a new manipulator or using an existing robotic system.