Structural Design Of A Deformed Wheelchair With Transfer Function

Due to the lack of effective functions in most wheelchairs on the market,nursing staffs usually have to transfer patients by hand.However,during the process of manual transfer,not only great labor is required,but also secondary injury to the disabled caused by friction and collision might happen.Hence,a good wheelchair using for effective nursing care is particularly important.For this purpose,a new kind of deformed wheelchair,which can automatically adjust human body posture and transfer patients laterally without any auxiliary equipment,is designed in this thesis.First of all,the basic performance and design requirements of a multifunctional wheelchair are determined to complete the integrated design on the basis of the analysis transfer and nursing requirements of patients.The design principles of the main functional mechanisms,including the backrest adjusting mechanism,the leg flexion and extension mechanism,and the lateral translation mechanism,are elaborated in detail,and the selection of each electric linear actuator of the wheelchair is determined.A three-dimensional modeling and its overall assembly are completed based on modular design method.Then,interference checking and functional simulation are carried out to ensure that the wheelchair can achieve the expected functions.After that,a kinematic model of the multifunctional wheelchair is developed and a series of simulations are conducted to investigate its kinematic properties.The simulation results-angle,angular velocity and angular acceleration curves of those principal mechanisms(the backrest adjusting mechanism,the leg flexion and extension mechanism,and the lateral translation mechanism)are analyzed to verify the stability of the reclining process of the wheelchair.In addition,mechanical models of the wheelchair reclining mechanisms are simulated to investigate its dynamic properties.The thrust curve of each linear actuator are obtained,and compared with the technical specifications to verify the rationality of the mechanical performance of the reclining mechanisms.Finally,this thesis employs finite element analysis of the main mechanisms of the wheelchair in the process of reclining and lateral movement.Results show that the structural strength and stiffness of the reclining and lateral mechanisms satisfy the requirements in various states of their operating conditions,respectively.The structural lightweight optimization is employed to those components with fairly enough safety margin of structural strength.The lightweight design of the wheelchair lateral plate and base frame are implemented by topological and direct dimensional optimization methods,respectively.After optimization,the weight of the base frame significantly decreases 47.54%,and the weight of the lateral plate is reduced by 18.28%.