Kinematic Analysis And Simulation Research Of Parallel Stabilized Platform Based On 3-RPS Configuration

The emergency medical system is a special medical system that is gradually developed in the practice of rescuing the wounded and sick in war and natural disasters.In other word,that is the emergency medical center or emergency station.As a key way of ambulance and transportation in the emergency medical system,medical vehicles are used to transport patients or provide emergency treatment for severely disabled persons.The parallel stable platform adopts the parallel mechanism as the basic mechanism.Compared with other stable platforms,it has the advantages of large parallel mechanism bearing,high rigidity,small cumulative error,easy to realize multi-axis coupling drive,etc.It can achieve fast dynamic response while being able to Guarantee high stability accuracy of sports equipment.Aiming at the problems that the multi-degree movement of medical vehicles in the process of moving directly affects the patients on the medical stretcher,which cannot provide a stable rescue and operation environment.In this paper,a stable platform for medical vehicle is designed based on the 3-RPS parallel mechanism,which can provide good stability for medical vehicle stretcher.The kinematic analysis and dynamic modeling and simulation research of the medical vehicle stabilization platform are carried out.The main contents of the paper are as follows:(1)A 3-RPS parallel mechanism is designed.The three-dimensional model of 3-RPS parallel stabilized platform is built by Solid Works.The static analysis of the key parts such as the upper platform and hinge bearing was carried out by using ANSYS to check the stiffness and strength of the structure.A 6-SPS parallel mechanism is designed and a three-dimensional model was built to simulate the multi-dimensional motion of the medical vehicle on the road.(2)By using the matrix analysis method,the transformation matrix between the dynamic coordinate system and the static coordinate system is derived.The inverse kinematic mathematical model of 3-RPS parallel stabilized platform is established,and the calculation formulas of the telescopic quantities of each branch chain drive rod are obtained.The basic motion indexes of the designed parallel stabilized platform are analyzed,and the results show that the overall structure of the platform meets the actual working requirements.(3)The 3d models of 3-RPS parallel stabilization platform and 6-SPS road surface simulation mechanism were imported into MATLAB/Simulink to generate the corresponding Sim Mechanics module.In the simulation environment of Sim Mechanics Second Generation,the stable platform is placed on the simulation platform,and the driver module and the basic PID control module of each branch chain are added.Through the control simulation platform with input single degree of freedom motion excitation to carry out lifting,pitching and roll motion,the simulation movement trajectory and related parameters of the platform on thesystem are analyzed to verify the feasibility of the designed stable platform structure and control scheme.(4)The fuzzy PID controller is designed,and the joint simulation system is built based on the optimization of fuzzy PID controller and inverse solution error quadratic feedback method.The optimization control of the joint simulation system by fuzzy PID control module and inverse solution error quadratic feedback method was verified by the lift,pitch and roll simulation experiment of 6-SPS road simulation mechanism and the composite motion simulation experiment of multi-degree-of-freedom motion combination.The simulation results show that the control strategy can effectively reduce the multi-dimensional movement of the ambulance stretcher caused by the road surface and reduce the influence of the dynamic model error,so that the 3-RPS parallel stabilization platform can achieve higher adjustment accuracy and stability tracking control accuracy.