An Optimization-Based Approach for Prosthesis Dynamic Modeling and Parameter Identification

In this paper, we propose an effective approach to model the prosthetic leg dynamics for amputees wearing active-transfemoral prosthesis (ATP) which is self-powered. To accommodate unexpected effects of thigh on knee joints, the dynamic prosthesis model has been derived using both the thigh-knee-shank and the knee-shank configurations. Correlated with the amputee’s walking data, a nonlinear optimization problem is then formulated to identify the model parameters and the gains of the PD controller which is used to control the input torque for the ATP, while reducing measurement errors of the data. Moreover, the identified models are validated by comparing the predicted dynamics with experimental measurements. The advantages of proposed method in terms of simplicity, flexibility, and accuracy are demonstrated by the high correlation coefficients and the low root-mean-square errors.Copyright © 2015 by ASME