Evaluation of initialization procedures for estimating upper limb kinematics with MARG sensors

Instrumentation able to estimate upper limbs kinematics has a lot of relevance in the context of rehabilitation of stroke patients. The systems based on inertial systems seem to be well suited for clinical environment and numerous authors have presented wearable systems interesting in terms of accuracy and easiness of implementation. These systems always require an initialization procedure and the authors do not justify clearly why they are using one method rather than another. In this paper two common initialization methods are presented and they are evaluated and compared on the basis of the kinematics tracking of upper limbs daily living activities. The experimental results show that an initialization based on functional axes is less sensitive to the respect of initialization conditions than a static initialization.