Animal-inspired design and aerodynamic stabilization of a hexapedal millirobot

TLDR

The study introduces a dynamic‑similarity‑based design and a novel experimental tuning method to achieve stable, low‑rotational‑energy locomotion in a hexapedal millirobot. The authors employ dynamic‑similarity scaling, adaptive locomotion strategies, and an aerodynamic rotational damper to tune and stabilize the robot’s limit cycles. The VelociRoACH achieves 2.7 m/s, the fastest scaled legged robot, and the aerodynamic damper lowers rotational energy, yielding robust, stable limit cycles that maintain speed.

Abstract

The VelociRoACH is a 10 cm long, 30 gram hexapedal millirobot capable of running at 2.7 m/s, making it the fastest legged robot built to date, relative to scale. We present the design by dynamic similarity technique and the locomotion adaptations which have allowed for this highly dynamic performance. In addition, we demonstrate that rotational dynamics become critical for stability as the scale of a robotic system is reduced. We present a new method of experimental dynamic tuning for legged millirobots, aimed at finding stable limit cycles with minimal rotational energy. By implementing an aerodynamic rotational damper, we further reduced the rotational energy in the system, and demonstrated that stable limit cycles with lower rotational energy are more robust to disturbances. This method increased the stability of the system without detracting from forward speed.