Adaptive Design Of Wheelchirseat Mechanism Forwheel-legged Climbing-stair

With the progress of science and technology,wheelchairs are constantly updated,through manual,electric and current intelligent.As the main means of transportation for the disabled and the elderly,it has brought great convenience to the travel of this kind of people.Compared with the ordinary electric wheelchair,the climbing wheelchair can not only realize the function of the ordinary wheelchair,but also realize the functions of climbing,crossing ditches and crossing obstacles,effectively expanding the travel range of the disabled and the elderly.For this reason,a hybrid wheelchair with wheelchair and legs is designed,in which the seat posture adjusting mechanism plays the role of adjusting the wheelchair posture and the center of mass of the whole machine.The accuracy of its action is directly related to the safety of the wheelchair movement,so the rational design of the structure has a vital role for the whole wheelchair.This paper mainly designs the position and posture adjusting mechanism of the wheelchair seat for climbing a building.The main research contents are as follows:Firstly,analyzing the shortcomings of the existing design schemes in practical work shows that the existing posture adjustment mechanism is difficult to meet the requirements.Based on the analysis of the functional requirements of the seat position and posture adjusting mechanism,this paper puts forward the deformation design of the position and posture adjusting mechanism by replacing the gear meshing angle adjusting device with a straight line push rod,and gives three deformation design schemes by analyzing the actual operation status of the position and posture adjusting mechanism,which provides a theoretical basis for the next configuration design.Secondly,because the metamorphic mechanism can change the degree of freedom and the topological relationship of the mechanism,the design theory of metamorphic mechanism is applied to the design of the seat position and posture adjusting mechanism to get the final scheme of the seat position and posture adjusting mechanism,and the kinematics model is established,the workspace is simulated,and the velocity and acceleration curves of the rods are further obtained.The static analysis is carried out,and the force at each hinge point is obtained by solving the matrix,which lays a foundation for the optimal design of the seat posture adjusting mechanism.Thirdly,genetic algorithm is used to optimize the parameters of components,and six sets of parameter solutions are determined based on the evaluation indexes of motion space,the force magnitude of key hinge points and the balance of mechanism,and the effects before and after optimization are compared.On this basis,the error analysis and compensation of position and posture adjustment mechanism are carried out,and the error compensation is quantitatively analyzed with the example of seat backward tilt,and is used to carry out the error compensation.MATLAB simulation verifies the validity and feasibility of the design scheme.