Design and Validation of a Wearable Robotic Tail for Human Balance Support

Abstract

Taking inspiration from the natural world, where some animals utilise tails for balance, this paper presents a Supernumerary Robotic Limb (SRL), in this case a wearable robotic tail, to support human balance. We showcase the modelling, design, manufacturing, and testing of the tail. It is mounted to a wearable harness, allowing for fast setup and easy don and doffing, i.e. attachment and removal. The tail's rotation is determined by the distance of a carried load from the user's body, with actuating motors serving the dual purpose of controlling the tail and acting as the counterbalance. This characteristic gives a higher counterweight to overall weight ratio when compared to related devices. Testing has demonstrated an accuracy of 89 % in position control and a rapid 57 ms response time. In trials with a healthy human participant, the system assists with balance, resulting in a 59 % smaller displacement of Centre of Pressure (CoP) when lifting a weight, contributing to better balance and safer posture. Wearable robotic systems such as this tail have the potential to be used in industries where manual labour often involves lifting heavy objects or adopting awkward postures.