Analysis of direct motion measurement system for design of above knee prosthesis

In this study, motion measurement systems (MMS) are designed and analyzed in the laboratory for the necessary use in the development of any electronic above knee prosthesis (AKP). A low cost 2D image based MMS is one of the designs in order to analyze gait dynamics and provide reliable reference base for the comparison with direct MMSs which are also designed subsequently. Three direct MMSs using several combinations with accelerometers and/or gyroscopes are configured in the experimental set up and the records are compared to those obtained from image based MMS. The virtual sensor method showed the best accuracy and the approach using the combination of gyroscope and accelerometer had a lower accuracy while the calculations based on single accelerometers provide the worst performance in the relative knee angle estimations. It is recommended that MMSs employing virtual sensor and assembly of accelerometer and gyroscope are more reliable platforms for AKP designs.