Control system and kinematic analysis of lower limb prosthetic knee joint

Abstract

In order to study the motion characteristics of the prosthesis, a three‐dimensional model of the test platform was established, and the corresponding control scheme was designed according to this model. For the lower limb prosthesis test platform, a fuzzy proportion‐integration‐differentiation (PID) control model was created. Second, the matlab modules were used to construct the virtual model, and the goal function‘s control research was conducted. Finally, a virtual model was created, and the outcomes were studied, in order to assess the differences between the control results of proportional‐integral‐differential controller and fuzzy proportional‐integral‐differential controller. The results verify that the test platform using fuzzy proportional‐integral‐differential controller is capable of greater stability. The lower limb prosthetic knee joint test platform was built, and the corresponding experimental research was carried out on the motion of the lower limb prosthetic knee joint. The experimental data showed that the angle error of the hip joint was within 2° when the normal human gait was walking on the ground. The error of the joint angle does not exceed 3°. The prosthesis can clearly better mimic the angles of the hip and knee joints.