Real-Time Feedback Control for Knee Prosthesis using Motion Fusion Algorithm in 6-DOF IMU

Abstract

Stump angle measurement (SAM) system was developed and tested for its use in the development of a low cost electronic knee prosthesis using an accelerometer to measure “tilt” angle of the residual stump during various phases of gait. This system provided real time feedback to control the actuator position for covering a wide range of mobility for the above knee amputees. However, this system is prone to high frequency noise resulting from gait events. These “noise” spikes triggered false threshold values resulting in incorrect operation of the actuator. In the proposed design, a 6-degree of freedom (6-DOF) sensor replaces the accelerometer from previous design. The modified algorithm uses complimentary filter to process the data from inertial measurement units (IMU). This new system produces sensitive yet smoother output, removing the drawbacks of the earlier system. This paper reports the comparative analysis of the SAM system using 6-DOF and accelerometer. These results using 6-DOF sensor will assist in the further development of an intelligent feedback system for low cost active prosthetic leg.