Tendon-driven continuum robots are of great promise in dexterous manipulation in long-narrow spaces, such as in-situ maintenance of aeroengines, due to their slender body and compliant hyper-redundant architecture. However, major challenges in implementing this come from mechanical design and morphology estimation: torsion and buckling issues induced by the intrinsic compliant architecture and the coupling of system gravity and distal loads; and low-accuracy morphology model influenced by complex load conditions. In this article, inspired by the contact-aided compliant mechanisms (CACMs), a novel continuum robotic system using the bearing-based CACM is developed to overcome the two intrinsic issues (i.e., torsion and buckling) while eliminating the implied wear due to friction at joint/socket interfaces without affecting its stiffness adversely. Subsequently, based on the chained beam constraint model, a comprehensive kinetostatic modeling framework is systematically derived, focusing on mechanism-oriented strategies (i.e., tendon routing friction, physical joint constraint, and section buckling estimation). Finally, various experiments are performed to verify the effectiveness of both our designed hardware and algorithm. It is demonstrated that the robotic system with such hardware and algorithm achieving the torsional stiffness outperforms the twin-pivot design at least 24 times, stiffness enhancement > 100 times, morphology error < 2.5% of the manipulator length, and avoiding the first-order instability. Additionally, we demonstrate the navigation experiment by using two developed control strategies to show the performances of the robotic system.

中文翻译：

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新型接触辅助连续体机器人系统：设计、建模和验证


肌腱驱动的连续体机器人由于其细长的机身和合规的超冗余架构，在狭长空间的灵巧操作（例如航空发动机的现场维护）方面具有广阔的前景。然而，实现这一点的主要挑战来自机械设计和形态估计：内在柔顺架构以及系统重力和远端负载的耦合引起的扭转和屈曲问题；以及受复杂载荷条件影响的低精度形态模型。在本文中，受接触辅助柔顺机构 (CACM) 的启发，开发了一种使用基于轴承的 CACM 的新型连续体机器人系统，以克服两个固有问题（即扭转和屈曲），同时消除由于摩擦引起的隐含磨损在接头/插座界面处，不会对其刚度产生不利影响。随后，基于链梁约束模型，系统地推导了一个全面的动静力建模框架，重点关注面向机制的策略（即腱走线摩擦、物理关节约束和截面屈曲估计）。最后，进行了各种实验来验证我们设计的硬件和算法的有效性。事实证明，采用该硬件和算法的机器人系统实现的扭转刚度比双枢轴设计至少优于双枢轴设计24倍，刚度增强> 100倍，形态误差<机械臂长度的2.5%，并避免了一阶不稳定。此外，我们通过使用两种开发的控制策略来演示导航实验，以展示机器人系统的性能。