AeroTail: A Bio-inspired Aerodynamic Tail Mechanism for Robotic Balancing

This paper presents a novel bio-inspired “tail” design that harnesses aerodynamic drag to generate torque for robotic balancing. Drawing inspiration from the natural world, this innovative approach aims to improve the efficiency of balancing robots while reducing their overall mass. While reaction wheels have been widely used for satellite stabilisation and inverted pendulum-like balancing robots, their inherent mass can be problematic in Earth's environment. Biomimetic research demonstrates that animal tails can produce torque for righting and manoeuvring during rapid movement due to their aerodynamic features, such as fur. Motivated by these observations, we proposed a bio-inspired tail mechanism that balances robots by exclusively utilising aerodynamically induced torques. To simulate this device, an inverted pendulum-based dynamic model is introduced, and the balancing process is governed by a PD controller. Comparative simulation studies examine the behaviours of a traditional reaction-wheel-based tail (RW tail) and the proposed aerodynamic drag-driven tail (AeroTail), discussing their respective advantages and limitations. The findings reveal that the AeroTail outperforms the RW tail in most metrics, achieving a remarkable 33.2% reduction in peak torque input and a 72.8% decrease in peak velocity requirement while not relying on extra mass to function.