Movable Anchor Cable-Driven Parallel Robot and Its Application in Ground Microgravity Experiment for Long-Span Flexible Manipulators

The microgravity environment in space eliminates the need to constrain the arm length of flexible manipulators, enabling their full flexibility for critical tasks such as on-orbit maintenance, assembly, and refueling. However, ground-based development of these manipulators still have to overcome gravity, making it challenging to accurately evaluate their performance in space. This study presents a ground microgravity simulation system based on cable-driven parallel robot (CDPR) and designed for long-span flexible manipulators. Existing methods such as air-floating, water-floating, and passive cable suspension systems suffer from limitations in sealing, multidimensional control, accuracy, and active response. CDPR utilize parallel cables to suspend objects and dynamically balance gravitational forces, offering advantages in structural simplicity, large workspace, full degrees of DOF, and high dynamic response. Traditional static anchor CDPR lack dynamic reconfiguration, active tracking compensation, and cable collision avoidance capabilities. To address these challenges, we propose a multi-anchor, high-precision dynamic anchor CDPR system. We established its dynamic model, developed cable collision avoidance algorithms, and implemented compliance control strategies. Experimental validation demonstrated a maximum gravity compensation error of 1.37 N for long-span flexible manipulators gravity compensation. This system provides a high-fidelity ground microgravity environment for space flexible manipulators, offering reliable experimental support for aerospace applications.