Considering Errors in differentiation procedure and experiment, optimization technique was employed to obtain segmental kinematic data and joint force data which approximate system governing equations.
Sagittal plane motion was studied based on eleven segments model with motion data from a movie camera (64frames/sec) and ground reaction data from a force plate.
The Center of mass of TNH (trank, neck, head) and each segment's angle was fitted to the sixth order Fourier series. Outward Recursion was used for segmental kinematic data and Inward Newton-Euler Recursive equation was used for joint forces and moments.
Then, there is an error in dynamic equilibrium equation for TNH, or system error. Gradient Projection Method was adopted to reduce system error subject to the curve fitting constraints.
Human body segments were modelled as ellipsoids and right elliptical solids model.
The optimal solution was verified by energy and power calculation.