Research On The Key Technology For The Micro-Nano Magnetorheological Damping Prosthetic Knee Joint

With frequent traffic accidents and natural disasters,the number of amputees has risen sharply.At present,medical technology can not regenerate limbs,prosthetics become the only effective way to help amputees recover their basic living conditions.Magnetorheological(MR)damped prosthetic knee joint with semi-active and controllable characteristics has become a research hotspot in the field of prosthetic application,depending on the fast response to external excitation and low energy consumption.The existing MR damped prosthetic knee joint has a huge and bulky structure,which affects the quality of human gait and the comfort degree of patients in the process of movement,and is difficult to be commercialized and popularized.Therefore,the development of the prosthetic knee joint with excellent performance,lightweight structure and low cost,has extremely important academic research and social application value.Based on the mechanism of magnetorheological effect produced by MR fluids with magnetic field,adding different mass fractions of nano-magnetic particles into the traditional micro-meter MR fluids.A testing system is built to test and compare the mechanical properties of the fluids,and the micro-nano MR fluids with better properties are developed,and a set of testing system is set up to study its mechanical properties.The magnetic induction intensity in the shear gap of the damper for prosthetic knee joint is simulated by ANSYS.The relationship between the magnetic induction intensity and the applied current in the shear gap of the micro-nano MR fluid damper is obtained,and the rationality of the magnetic circuit design of the damper is verified.To better simulate the gait of human body during movement,the knee joint mechanism of prosthetic knee joint is simplified to a planar four-bar linkage mechanism,and the upper and lower connecting rods are connected to the residual limb receiving chamber and micro-nano MR fluid damper respectively.A new type of micro-nano MR damper prosthetic knee joint is designed,and the motion state of the knee joint of human body in walking on the flat ground is simulated,which provides theoretical and experimental basis for the further research of MR damped prosthetic knee joint.