Structural Design And Research Of Posture Adjustment Stretcher Vehicle Based On Parallel Mechanism

As a medical transport equipment,stretcher car is essential in the process of transporting patients outside the hospital.When transporting,ambulance personnel often face complex environments such as communities and outdoors without elevators,which hinder the rapid transfer and treatment of patients.Therefore,a posture-adjusting stretcher vehicle based on parallel mechanism is designed to meet the current needs.The posture adjustment stretcher car not only has the basic functions of up and down stairs,over stair platform,partial bed contraction,but also has the posture adjustment function of the stretcher car through the parallel mechanism.When transferring patients,the bed body device can be adjusted according to different patients and transfer environment.According to the design requirements of the stretcher vehicle,the structural design,workspace solution,kinematics analysis,gait planning,dynamics simulation and prototype test are carried out in this paper.First of all,according to the use place and functional requirements of the stretcher car,the stretcher car is composed of three parts : walking mechanism,posture adjustment mechanism and bed body device.Select the movement mode of each part of the mechanism of the stretcher car,complete the calculation and selection of the driving components,and use Solid Works software to carry out three-dimensional modeling of the mechanical structure of the stretcher car.Among them,the kinematics analysis of the parallel posture adjustment mechanism is carried out to verify whether its workspace can meet the use requirements.Secondly,the lateral load transfer rate is used to analyze the lateral overturning risk of the stretcher vehicle.The trajectory of the stretcher car going upstairs,going downstairs and crossing the platform is planned.In the planned trajectory,the change of the center of gravity position caused by the posture adjustment of the stretcher car is analyzed through the coordinate system motion transformation.Based on the stability index,the stability of the stretcher car upstairs,downstairs and across the platform is quantitatively analyzed.Thirdly,in order to make the posture adjustment of the stretcher truck stable,the motion of the stretcher truck and the motion characteristics of the parallel posture adjustment mechanism are analyzed,and the leveling method of the parallel mechanism is determined.The ADAMS simulation analysis of the stretcher car upstairs,downstairs and over the platform is carried out to verify the correctness of the theoretical analysis of the stability of the stretcher car.ANSYS WORKBENCH is used to analyze the important parts of the stretcher car,which lays a foundation for the prototype production and test of the stretcher car.Finally,based on SimMechanics,the visual simulation of the parallel mechanism of the stretcher vehicle is carried out to verify the accuracy of the posture adjustment of the stretcher vehicle.The test prototype of the posture adjustment stretcher car is built,and the bed body device overturning test and upstairs test are carried out.The test results show that the stretcher car can successfully complete the motion task and verify the feasibility of the design.