Structural Design, Modal Analysis and Manufacturing of an Intelligent Robotic Walker

Abstract

Abstract People with physical disabilities and chronic conditions often rely on assistive tools for their daily activities. Enhancing the affordability, design, and comfort of these devices can significantly improve their practicality for home use and enhance the life of individuals in need. Despite mechanical advancements in traditional walkers, they have not fully integrated robotic capabilities. This research aims to address this gap by providing practical solutions to a range of motor impairment challenges and developing a robotic walker with an optimum design for stability. The innovative walker features a 4-wheel structurally stable design, supported by the fundamental implementation of a Walker Tipping Index (WTI). Additionally, it includes motion planning based on the user’s intention, collision detection, and fall prevention, all with the goal of enhancing the walking experience for individuals with motor impairments. The design of the walker chassis prioritized postural stability in all directions, utilizing a WTI calculator to determine overall dimensions while ensuring the index remained below 0.5 in all directions (front-back, left-right). For the structural integrity of the design, Finite Element Analysis (FEA) was conducted for symmetric and asymmetric loading, modal analysis, and buckling analysis. Results indicated a factor of safety above 2 for all worst-case loading conditions, with a buckling load factor of 5.94 and a natural frequency optimized to exceed the motor’s operational frequency. Fabrication of the walker utilized AISI 4130 steel tubes to minimize weight while maximizing strength. LiDAR and force Sensor, electronics, and battery mounting components were 3D printed using carbon fiber-infused PETG, and Aluminum 6061-T was used for the motor mounts which were manufactured using CNC milling. Finally, a comprehensive physical stability test in all directions was conducted to validate the WTI calculations and confirm the postural stability of the walker structure.