Design And Research On Stair-climbing Wheelchair With Logarithmic Spiral Wheel

With the acceleration of aging process and growing population of people with disabilities,ordinary wheelchairs with ground walking function can not meet the requirements of the elderly and the disabled.In order to facilitate their daily life and improve their quality of life,this thesis summarizes the existing products and research results of stair-climbing wheelchair,and proposes a new type of stair-climbing mechanism(logarithmic spiral wheel,LS-wheel),and designs a pair of electric wheelchair with LS-wheels which is functional,superior performance,and cost-effective.Firstly,the working principle of LS-wheel is introduced and the movement model of LS-wheel is established,which is divided into the movement model of LS-wheel on the stair step plane and the movement model of LS-wheel climbing stairs.The conditions that LS-wheel climbs stairs continuously is received based on the movement model of LS-wheel,and the logarithmic spiral parameters that meet the conditions are solved according to the height and width of the step,finally,the stair-climbing trajectories of different LS-wheels with different logarithmic spiral parameters are obtained through simulation,which determines the parameters of LS-wheels for the electric wheelchair.Secondly,the functional requirements in actual use of stair-climbing wheelchairs are analyzed.The wheelchair is divided into three parts according to the design requirements: stair-climbing,ground-driving,and seat-leveling.Each part is designed specifically and the three-dimensional models of each part and overall of the wheelchair are created by SolidWorks.Then,the stair-climbing process of wheelchair and the working process of each climbing stage are demonstrated.Thirdly,a dynamic simulation analysis of the stair-climbing process of LS-wheels wheelchair is carried out with the help of ADAMS virtual prototyping technology.The movement trajectories of occupants’ center-of-mass and the instantaneous output power of the motors are compared with triple-wheels cluster wheelchair.The variable-angular-velocity driving control strategy of LS-wheels wheelchair is discussed and the movement speeds of occupants’ center-of-mass under different driving control strategies are compared through simulation.Finally,the stress states of LS-wheel during stair-climbing process are analyzed and a structure of LS-wheel is designed.Then,the structure is optimized according to the static analysis results of ANSYS.And a rigid-flexible coupling simulation of the wheelchair with final structured LS-wheels is carried out by ADAMS,which verifys the feasibility of the final structure.