UC Berkeley

Modern emergency response operations increasingly use remote ground-based sensors to provide real-time situational awareness for first responders. However, human users often must personally enter a dangerous situation to place the sensors. The seamless deployment of such sensors without human intervention allows for faster, wider distribution at minimal risk to human lives. This work presents a systematic approach to the design of impact-resistant tensegrity landers capable of autonomous high-altitude aerial deployment of critical sensor payloads in disaster scenarios.

Tensegrity structures are derived from the concept of “tensile integrity” and are composed of rigid rods suspended by elastic cables in a tension network. Their lightweight and flexible properties protect the sensor payload from landing impacts at high velocities. Design equations and simulation models are first used to inform the hardware design of the tensegrity structure and provide upper-bound estimates of viable tensegrity lander designs. A comprehensive range of drop test experiments are conducted to validate the impact behavior and demonstrate the impact-resistance in the highest-altitude drop test experiments of tensegrity landers to date. The experimental results are leveraged to propose empirical scaling laws for the rapid and efficient design of future generations of tensegrity landers. Furthermore, two new tensegrity lander designs, an asymmetrically-weighted structure and a badminton-inspired structure, augment the tensegrity with self-stabilizing functionality to control for the landing orientation of optimal impact mitigation as indicated by the drop test experiment data. The results reveal further opportunities to optimize the design of the structure by aligning the stiffness of the structure with the desired landing orientation. Such a tailored structure can have motorized cables decoupled from the impact event that can then be used to provide locomotion for an ideal hybrid lander-rover tensegrity system.

Overall, the work contributes design methods, reorientation capabilities, and validated hardware prototypes to the grand challenge of tensegrity robotics: demonstrating a fully autonomous tensegrity robot capable of safely navigating through unstructured terrain.