A Robotic Cane for Balance Maintenance Assistance

Abstract

This paper proposes a robotic cane that helps users to stand and maintain their balance while standing and walking. The design is based on an inverted pendulum model, uses a smart omnidirectional wheel, and is linearized by the Lie algebra method (LAM) combined with a nonlinear disturbance observer that estimates the external force applied by the user. The hardware and mathematical model of the robotic cane are analyzed in detail. The hardware design is complete, and considers the weight and battery capacity. The performance of the controller is confirmed in three-dimensional simulations and in physical experiments. The robotic cane tolerates a large fluctuation angle from its equilibrium point. It also has a fall prevention function, which is among the most desirable functions of any walking assistance device, and responds quickly to a human force. The balance maintenance functions are as follows: self-balance, standing and walking assistance, fall prevention, and a mechatronic safety mode. In experimental measurements of the cane in use, the gyroscope sensor insignificant vibrations on the user's bodies, verifying the effectiveness of the robotic cane in daily life activities. The performance of LAM is also compared with that of the linear quadratic regulator.