Analysisi On The Motion Characteristics And Reliability Of The Rear Leg Adjusting Mechanism Of Climbing Whellchair

With the advancement of science and technology and the development of society,people have higher and higher requirements for the quality of life.People with disabilities and the elderly have higher requirements for their travel tools,and ordinary wheelchairs cannot meet their needs.At present,ordinary electric wheelchairs can only run on flat ground or on a small slope.When electric wheelchairs encounter steps,trenches and obstacles,they cannot cope.They can only rely on human resources to help them overcome obstacles and trenches.Restricts the travel of elderly and disabled people.This project designed a wheel-leg hybrid eight-footed climbing wheelchair for climbing stairs,which effectively expanded the travel range of the elderly and the disabled.The hind leg mechanism,as the most important part of the wheelchair for climbing stairs,provides the main power for the chassis of the wheelchair for climbing stairs,and plays the role of adjusting the position of the center of gravity of the wheelchair.The performance of the hind leg mechanism determines the performance of the entire climbing wheelchair,so the rational design of the hind leg mechanism plays a vital role in the entire wheelchair.This paper focuses on the kinematics analysis,reliability analysis and optimization design of the hind leg mechanism of a climbing wheelchair.First,a brief introduction to the climbing wheelchair is made.The kinematics model of the rear leg mechanism of the climbing wheel wheelchair is established by using the complex vector method,and the angular displacement,angular velocity,and angle of each rod in the rear leg adjustment process are analyzed.Acceleration.The force of each hinge point in the hind leg mechanism was analyzed using the D’Alembert principle.Secondly,based on the analysis of the motion characteristics and the force of the hind leg mechanism,the genetic algorithm based on the analytic hierarchy process(AHP)was used to optimize the parameters of the components,and the angular displacement of the rear leg mechanism rod 2 and the force of the hinge point For the evaluation index,the rod length of the hind leg mechanism was optimized to obtain the optimal solution.The force situation of the optimized front and rear hinge points,the speed and acceleration of each member are compared.Finally,since the clearance of the motion pair of the hind leg mechanism will affect the motion characteristics of the hind leg mechanism,it is assumed that the reaming hole and pin in the motion pair are in continuous contact and conform to the continuous contact model,and the motion pair is regarded as a link without mass.The Lagrangian dynamic equation of the hind leg mechanism is established,and the expression form of the output parameters of the hind leg mechanism is obtained when the clearance is considered.Using Matlab to perform matrix operations on the dynamic equations of the hind leg mechanism,and obtain the kinematic characteristics of the hind leg mechanism considering the clearance of the motion pair,and obtain the dynamic parameters.Effects of leg mechanism kinematics output parameters.Further analyze the influence of the gap of the motion pair on the reliability of the motion accuracy of the hind leg mechanism,and the effect of the basic size error on the reliability sensitivity.