Damping Characteristics Analysis And Performance Optimization Of Smart Magnetorhelolgical Damper

In recent years,with the rapid development of robotics technology,more and more robots have been applied to the field of rehabilitation medicine,especially on bionic prostheses.For this kind of bionic robot,the traditional passive damping device is difficult to meet the stability and comfort during walking,so the compact magnetorheological damper with flexible characteristics shows a good application prospect.As a key component in robot equipment,the magnetorheological damper has higher requirements on its volume size and power density than ordinary engineering applications.Moreover,the research of magnetorheological damper involves multi-physics fields,and the interaction between the physical fields has a great influence on its damping characteristics.Therefore,studying its damping characteristics under multi-physics fields is of great significance for promoting the application and development of magnetorheological damper in bionic prostheses.This paper takes a small magnetorheological damper as the research object,numerical calculation method is adopted to carry out multi-physical field simulation analysis on it,to study the influence of external excitation and main structural parameters on its damping characteristics,and combined with the response surface method to optimize the performance of the magnetorheological damper.The main research contents of this paper are as follows:Firstly,analyze the working principle of the magnetorheological damper,establish a calculation model of the output damping force of the magnetorheological damper,and discuss the influence factors of the damping force.Secondly,based on the modified Bingham model,considering the weak compressibility of the magnetorheological fluid,a multi-physics simulation model of the magnetorheological damper was established in the COMSOL simulation software.Based on the moving mesh technique,the sine motion of the piston is simulated,and the magnetorheological damper is calculated in a multi-physics field.The distribution of the magnetic field inside the magnetorheological damper and the distribution of fluid viscosity,flow rate and pressure under different magnetic fields are discussed.Then,based on the established multi-physics simulation model,the single factor analysis method is used to study the influence of external excitation parameters such as control current,vibration amplitude,vibration frequency and key structural parameters such as damping gap width,effective magnetic pole length,piston diameter,and magnet yoke diameter on damping characteristics.Finally,combining the multi-physics simulation calculation and response surface method,the two indexes of damping performance and the response model of structural parameters are fitted,and the accuracy of the response model is verified.The response model was used to optimize the performance of the damper,and the effectiveness of the response surface method in optimizing the performance of the damper was verified by simulation calculation.The results show that the damping force output of the optimized magnetorheological damper is significantly increased,and the dynamic adjustable coefficient is increased by 17.10%.