A Rapid Tunable Stiffness Bistable Adaptive Tensegrity Joint for Gripper and Swimmer

Joints are the core components of robotic actuation systems. Their performance directly affects the system’s dynamic characteristics. However, rigid and flexible joints both face a trade-off between environmental adaptability and response velocity due to their structural properties. A bionic tensegrity joint inspired by biological tensegrity principle is proposed. We present its structural design and stiffness model. The joint features tunable bistability, allowing synergistic optimization between adaptability and response velocity. Experiments show that the joint has negative stiffness and fast response. To validate the effectiveness of the proposed joint design, a gripper and a swimmer were developed. The gripper demonstrates a high response velocity of 56 ms while maintaining a payload capacity of up to 4 kg. Leveraging the bistable tensegrity joint, the swimmer achieves a swimming speed of 1.1 body lengths per second (BL/s). A novel robotic design framework centered on rotational tensegrity joints has been developed, which demonstrates significant potential for agile locomotion, human-robot interaction, and adaptive manipulation.