*4.1. Mechanical Design of the Exoskeleton*

To realize accurate digit joints' motion control mechanically, joints' rotation axes of both the hand exoskeleton and the human hand need to be aligned in motion. To validate the concept, the trajectory of joints' rotation axes for both the hand exoskeleton and the human hand are simulated and compared. In a scenario in which all finger joints rotate 60◦ , the human hand DIP and PIP joints' trajectories obtained from Opensim fit well with the trajectories of the hand exoskeleton (Figure 15), suggesting a comfortable wear experience and potential for accurate digit joint motion control.
