Page 300 - Handbook of Biomechatronics

292 Andres F. Ruiz-Olaya et al.

of the user in accordance with the user’s motion intention by monitoring the
electromyographic (EMG) signals of certain muscles involved in the upper-
limb motion. At least five degrees of freedom (DOF) must be provided
assuming that the location of the rotation center of the shoulder joint of
the exoskeleton is the same as that of the user. As a matter of fact, more
DOF are required to assist all upper-limb motion, since the human shoulder
complex, which consists of the scapula, clavicle, and humerus, moves con-
jointly, providing seven DOF for upper-limb motion (Zatsiorsky, 1998).
An example of upper-limb exoskeleton is the wearable orthosis for
tremor assessment and suppression (WOTAS) device, which was presented
within the framework of the DRIFTS project as a promising solution for
patients who cannot use medication to suppress the tremor (Manto et al.,
2003). WOTAS exhibits three DOF corresponding to elbow flexion-
extension, forearm pronation-supination and wrist flexion-extension, while
restricting adduction-abduction movements of the wrist (Fig. 4). The
ARMin system is a rehabilitation exoskeleton with six DOF designed to

Fig. 4 WOTAS final version for control of human upper-limb three movements control:
flexion-extension elbow, flexion-extension wrist, and pronation-supination forearm.
(From Rocon, E., Ruiz, A.F., Belda-Lois, J.M., Moreno, J.C., Pons, J.L., Raya, R., Ceres, R.,
2008. Diseño, desarrollo y validación de dispositivo robótico para la supresión del temblor
patológico. Revista Iberoamericana de Automática e Informática Industrial RIAI, 5(2),
79–92, with permission from Elsevier.)