Adaptive Stiffness: A Biomimetic Robotic System with Tensegrity-Based Compliant Mechanism

TL;DR

This work presents a tensegrity-based biomimetic robot integrating rigid-flex coupling and a compliant mechanism to achieve variable stiffness and versatile locomotion in ill-defined environments. It combines spine-like multi-layer tensegrity modeling with adaptive force density, a parametric design workflow, and a mechatronic control system that leverages inverse kinematics and real-time simulations. Experimental results demonstrate enhanced mobility, a wide range of motion, and environment-aware adaptation through stiffness modulation, while acknowledging challenges such as cable relaxation and friction. The approach promises practical applicability in constrained spaces and complex tasks, with future directions including model-free control and advanced materials to further improve robustness and scalability.

Abstract

Biomimicry has played a pivotal role in robotics. In contrast to rigid robots, bio-inspired robots exhibit an inherent compliance, facilitating versatile movements and operations in constrained spaces. The robot implementation in fabrication, however, has posed technical challenges and mechanical complexity, thereby underscoring a noticeable gap between research and practice. To address the limitation, the research draws inspiration from the unique musculoskeletal feature of vertebrate physiology, which displays significant capabilities for sophisticated locomotion. The research converts the biological paradigm into a tensegrity-based robotic system, which is formed by the design of rigid-flex coupling and a compliant mechanism. This integrated technique enables the robot to achieve a wide range of motions with variable stiffness and adaptability, holding great potential for advanced performance in ill-defined environments. In summation, the research aims to provide a robust foundation for tensegrity-based biomimetic robots in practice, enhancing the feasibility of undertaking intricate robotic constructions.

Figures (21)

• Figure 1: Design methodology.
• Figure 2: Two types of deformation.
• Figure 3: Left: Tensegrity vertices. Right: Linear augmentation.
• Figure 4: Structural composition.
• Figure 5: Left: Rigid-Flex coupling. Right: Rhombic configuration transformations.