基于下肢假肢的阶梯式变间隙磁流变阻尼器设计

针对下肢假肢步态变化时所需阻尼力大小不同的问题，提出一种基于下肢假肢的新型阶梯式变间隙磁流变阻尼器（MRD）。基于Bingham力学模型设计MRD的两级阻尼间隙宽度及主要结构尺寸，通过ANSYS Maxwell分析其内部磁场分布，采用Simulink仿真输出阻尼力。结果表明：阶梯式变间隙MRD步行时的工作间隙为1.6 mm，最大阻尼力为902.7 N；跑步等其他复杂步态时的工作间隙为0.6 mm，最大阻尼力为2 033.7 N，满足不同步态的阻尼力要求，且该MRD的最大工作电流为0.4 A，极大降低了阻尼器功耗。所提出的阶梯式变间隙MRD具有阻尼力分级输出、可调范围大、能耗低的优点，可代替阻尼间隙固定的传统MRD应用于假肢系统。

Design of a Magnetorheological Damper with Stepped Variable Damping Gap for Lower Limb Prosthesis

A new stepped variable gap magnetorheological damper (MRD) based on lower limb prosthesis was designed for the issue of different magnitudes of damping force required for gait changes.Based on the Bingham model,the two-step damping gap width and main structure dimensions of the MRD were designed,the internal magnetic field distribution was analyzed by ANSYS Maxwell,and the output damping force was simulated by Simulink.The results show that the maximum operating current of the MRD is 0.4 A,its operating gap is 1.6 mm and its maximum damping force is 902.7 N when walking;the operating gap is 0.6 mm and maximum damping force is 2 033.7 N when running and other complex gaits,which can meet the damping force requirements of different gait.The stepped variable gap MRD has the advantages of graded damping force output,large adjustable range,and low energy consumption,and it can be used in prosthetic systems instead of conventional MRD with fixed damping gaps.