Hybrid Continuum Robot Designs and Architectures for Healthcare Applications

Continuum robots offer enhanced flexibility and dexterity compared to traditional rigid-link systems, making them well-suited to minimally invasive and endoluminal interventions. Numerous design and actuation configurations have been proposed, spanning from hard yet flexible robotic structures to passively adaptable monolithic soft-bodied designs. However, unimodal approaches often face trade-offs between compliance, range of motion, and control precision. Recently, hybrid continuum robots that integrate multiple design and/or actuation strategies within a single architecture have emerged. By spanning a broader range of materials and actuation approaches, hybrid continuum robots aim to overcome the limitations of single-modal systems and present new capabilities suited to challenging clinical applications. The presented review specifically focuses on the designs, architectures, and configurations of this emerging field, emphasizing how distinct structural and actuation combinations present significant diversity in performance and application. We first stratify hybrid continuum robot architectures by their material composition, capturing hard- and soft-bodied designs in exclusive or combined configurations. Within each high-level grouping, we consider the range of associated actuation methods and clinical applications presented to date. Adjacent approaches that achieve hybrid performance through active adaptability are also considered. Finally, we discuss the open challenges and opportunities for continuum robot hybridization in the context of clinical applications and future translation.