Design And Analysis Of A New Type Of Power-assisted Mechanism For Stair Climbing

With the deepening of the aging of China's population,the number of the elderly population and the number of partially disabled people is increasing.How to overcome the stair obstacles and improve the ability to travel has become a hot topic in the research of helping the elderly and disabled.The research at home and abroad mainly focuses on the electric wheelchair and the wearable exoskeleton.The traditional electric wheelchair requires the assistance of others,and it is suitable for a small range.However,the exoskeleton system is expensive and complex,and its practical commercial application is not yet mature.This paper analyzes the advantages and disadvantages of stair climbing mechanism and the characteristics of human movement,proposes a new type of power-assisted mechanism for stair climbing that combines cable-driven parallel mechanism and crawler type stair climbing mechanism,and analyzes the overall design scheme of the mechanism and the key problems of the mechanism design.First of all,according to the design requirements of the climbing mechanism,the movement characteristics of the lower limbs of the human body were studied,the relevant data needed for the assisted movement were obtained,and the combination scheme of the assisting mechanism and the climbing mechanism was determined.A new type of power-assisted mechanism for stair climbing is designed by combining the cable-driven parallel mechanism with the crawler mechanism.The design of the key structure of the climbing mechanism was completed.Then,the kinematics of the cable-driven parallel mechanism is analyzed,the mathematical model of the cable-driven parallel mechanism of three degrees of freedom with passive constraint is established,the position analysis,velocity analysis and working space of the terminal moving platform are studied,and the force-closed working space of the moving platform is studied by using the convex analysis theory.Finally,the virtual prototype modeling of the power-assisted mechanism and the stair climbing mechanism is completed.ADAMS software was used for kinematic analysis and dynamic analysis,which verified the feasibility of the new type of stair climbing booster mechanism.ANSYS Workbench was used to analyze the key structure of the new stair climbing mechanism by finite element method,including static stiffness analysis and modal analysis,which verified the reliability and safety of the mechanism.