Study On Hydraulic Damping Of Seven-axis Prosthetic Knee Joint And Design Of Oil-filled Method

Due to war,diseases,work-related injuries,traffic accidents,and natural disasters,there are currently 2.2 million patients with amputees of the lower limbs in China.Because the current medical level has not been able to achieve limb regeneration,the installation of prosthetics for these patients with lower limb amputation has become the only option at present.The main functional parts of the lower extremity prosthesis are the knee joint and prosthetic foot,but the knee joint is the most important.At present,China does not have the production capacity of high-end prosthetic knee joints,and most of them are imported from developed countries.However,overseas prosthetic knee products are very expensive,which makes it difficult for tens of thousands of lower limb amputees to restore normal limb function in China.Therefore,the study of prosthetic knee joints has important social significance.This article takes a seven-axis hydraulic prosthetic knee as the research object,and its hydraulic damping system was studied.There are two research objectives: First,As there is no special hydraulic oil for the knee joint of hydraulic prosthesis in China,the purpose of this study is to formulate the hydraulic oil parameters for the knee joint of hydraulic prosthesis for patients of different weights.Second,we design method of oil for the prosthetic knee joint hydraulic system.In order to achieve the first goal,this paper adopts a combination of numerical simulation and theoretical calculation.The combination point is the torque required by the knee joint.First,the torque required for knee joint rotation is obtained by theoretical calculation,and then the knee closure hydraulic system of prosthesis is simulated numerically.In the process of the numerical simulation,the hydraulic oil parameters are continuously adjusted to output the required torque.In order to make the final output torque of the prosthetic knee more close to the normal gait,the data used in the numerical simulation of this article are all normal human knee data.In order to obtain the motion data of normal knee joints,this article uses the Vicon three-dimensional movement capture system to collect the normal knee joint movement data.In order to achieve the second goal,we combined the structural features of the prosthetic knee joint hydraulic system,analyzed the possibilities,and finally designed a method for filling the prosthetic knee joint hydraulic system.Then the method is verified by numerical simulation and improved.