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324 Borna Ghannadi et al.

devices are categorized separately. Nonetheless, we have considered them as
a type of manipulanda (cable-based manipulanda). Cable-based manipulanda
can also be categorized as single-robot and multirobot. “DIEGO” (from
Tyromotion GmbH) and “MariBot” (Rosati et al., 2005) are examples of
cable-based single-robot manipulanda. “GENTLE/S” (Loureiro et al.,
2003), which is an integrated “HapticMaster” with a cable-based mecha-
nism, is a type of cable-based multirobot manipulanda.
Exoskeletons can provide movements to particular joints (see Fig. 1),
and the number of anatomical movements can exceed 6. Nonetheless,
increasing the number of moving parts increases the number of device mod-
ules, so the system setup becomes difficult. Moreover, since the shoulder has a
variable joint center, the mechanical design and control algorithms become
morecomplicated.Mostlytheserobotsarecombinedwithweightsupporting
devices or manipulanda (semiexoskeleton in Fig. 1). “ArmeoPower” (which is
basedon“ARMinIII”(Nefetal.,2009))and“ArmeoSpring”(whichisbased
on “T-WREX” (Sanchez et al., 2004)) are commercial semiexoskeletons
(Proiettietal.,2016;Maciejaszetal.,2014).Ifexoskeletonsarenotconnected
to any external mechanism, they will be mobile (mobile exoskeleton in Fig. 1).
“CyberGrasp” (Adamovich et al., 2009) and “RUPERT” (Balasubramanian
et al., 2008) are examples of these devices.
Manipulanda are most often used for training nonmobile gross move-
ments (e.g., reaching task); on the other hand, exoskeletons are perfect
for training mobile or joint-specific movements (i.e., perform specific
movements of distinct body joints, e.g., grasping task). Manipulanda usually
enjoy lower cost margins than exoskeletons as well as less complicated setups
and shorter patient-preparation time for therapy. The selection of one of
these two different devices highly depends on the level of the patient’s
disability; for example, in early stages of stroke when the patient is more vul-
nerable and unstable, manipulandum training seems to be a safer choice.
Mechanical design of these devices can be improved by considering the
patient’s ergonomics and removing higher transformation ratios using effi-
cient direct-drive motors. Furthermore, exoskeletons benefit from the use of
lighter parts with a high mechanical strength to be attached to the patient’s
body. However, these advancements are limited by the production cost;
finding the best price-quality trade-off requires proper design methodology,
such as model-based system engineering (MBSE). MBSE is a designated
modeling application that supports system requirements, design, analysis,
verification, and validation of conceptual designs throughout the develop-
ment and lifecycle phases.