全通道内置阀式磁流变阻尼器的设计及性能分析

Design and performance analysis of full fluid channel magnetorheological damper with built-in valve

针对磁流变假肢中磁流变阻尼器体积大、输出阻尼力较小的问题,设计了一种全通道内置阀式磁流变阻尼器。首先,通过布置导磁楔形环和隔磁环,引导磁力线穿过全部液流通道,并进行了阻尼器磁路分析和输出阻尼力数学模型的推导;其次,利用ANSYS软件进行了阻尼器电磁场仿真;再次,采用多目标遗传算法优化阻尼器的结构参数,并仿真对比了优化前后阻尼器的平均磁感应强度和输出阻尼力;最后,加工了结构参数优化前后的阻尼器样机,并对其进行了动力学性能测试与分析。结果表明:优化后阻尼器活塞头的体积减小了24.4%,最大输出阻尼力提高了24 N;当电流为2 A时,优化前最大输出阻尼力仿真值为295.38 N,测试值为309.76 N,误差为4.6%;优化后最大输出阻尼力仿真值为307.77 N,测试值为333.76 N,误差为7.6%。所设计的全通道内置阀式磁流变阻尼器体积较小,输出阻尼力较大,液流通道的空间利用率较高。研究结果可为磁流变假肢中磁流变阻尼器的设计提供参考。

Aiming at the problems of large volume and small output damping force of magnetorheological damper(MRD)in MR prosthesis,a full fluid channel MRD with built-in valve was designed.Firstly,the magnetic flux lines were guided through all fluid flow channels by arranging arranged with magnetically conductive wedge rings and a magnetically separating ring,and the magnetic circuit analysis and derivation of mathematical model of output damping force were carried out.Secondly,the electromagnetic field of the damper was simulated by ANSYS software.Thirdly,the structural parameters of the MRD were optimized by using the multi-objective genetic algorithm,and the average magnetic flux density and the output damping force of the damper before and after optimization were simulated and compared.Finally,the damper prototypes were machined before and after the optimization of structural parameters,and the dynamic performances were tested and analyzed.The results showed that the volume of the piston head was reduced by 24.4%and the maximum output damping force was increased by 24 N after optimization.When the current was 2 A,the simulated value of maximum output damping force before optimization was 295.38 N,and the experimental value was 309.76 N,with an error of 4.6%;the simulated value of maximum output damping force after optimization was 307.77 N,and the experimental value was 333.76 N,with an error of 7.6%.The designed full fluid channel MRD with built-in valve had smaller volume,larger output damping force and higher utilization rate of fluid flow channel space.The research results can provide reference for the design of MRD in MR prosthesis.