System Design for Modular Tensegrity Robots

In complex scenarios such as planetary exploration and post-disaster rescue, environmental challenges and task diversity impose high demands for robustness and versatility on deployed robots. Tensegrity, as a unique paradigm that strikes a balance between rigid and soft structures, offers exceptional robustness. While its inherent compliance and flexibility equip tensegrity-based robots with advantages, the structural irregularity also presents challenges. Existing research on tensegrity robots has demonstrated their various capabilities but largely focuses on specific applications, missing the versatility needed for multifaceted scenarios. This thesis introduces the Modular Tensegrity Robot (MoTeR) and its constituent module, the Symmetrical Tensegrity Mechanism (STeM). MoTeR achieves the scalability and reconfigurability of tensegrity robots through modularising a three degrees of rotational freedom tensegrity octahedron. The design of the STeM module starts from the principles of tensegrity structures and introduces the concept of underconstrained transition region, achieving a seamless integration with rigid structures. This offers improved agility and connectivity of tensegrity structures for robot actuation. Leveraging the features of STeM, MoTeR effectively imitates natural animal morphologies and the corresponding gaits, and features a dual-mode locomotion capability using wheels as complementation. Through employing the force closure principle and CPG models, this thesis implements both low-level and high-level control for the robot. Evaluations conducted across aspects including control, structure, and locomotion confirm that, while retaining the inherent compliance and flexibility of tensegrity, MoTeR realises agile, controllable structural deformation and demonstrates stable polymorphic locomotion capabilities. The characteristics of MoTeR underscore the broad potential of highly modular tensegrity robots in adapting to different scenarios and diverse tasks. The design philosophy developed in this thesis should offer valuable insights for future research in modular tensegrity robots.