Multi-Factor Optimization and Failure-Tolerant Design of Cable-Driven Parallel Manipulators in Deep-Sea Robotics

This article presents a framework for optimizing cable-driven parallel manipulators (CPMs) in deep-sea environments, addressing factors as failure tolerance, stiffness, and workspace within a unified framework. While previous studies have examined these factors individually, few have integrated them into a unified framework. The presented framework evaluates CPMs with six, eight, and ten cables, using inverse kinematics, optimization, and stiffness analysis. The six-cable framework is fully constrained, whereas the eight-cable and ten-cable systems are over-constrained, providing additional redundancy in failure scenarios. Post-failure tensions are maintained within safe bounds, defined by mechanical load ratings and operational safety margins. Results indicate that increasing the number of cables improves workspace coverage, enhances stiffness, and reduces post-failure tensions. The ten-cable configuration, in particular, increases operational volume by approximately 20% and reduces peak post-failure tensions by around 15% compared to the six-cable baseline. Our framework also considers adaptive positioning strategies to improve system performance under varying ocean conditions. Future work will analyze the effects of wave-induced motions on system stability and develop sensor-based failure-detection techniques to enhance real-time failure mitigation and system robustness in dynamic environments.