Abstract—Stroke is the third cause of all disabilities for people
over 25 years old. Indeed, the percentage of people who suffer
from hemiplegia after stroke is higher than 75%. Patients with
hemiplegia have considerable difficulty performing activities of
daily living, such as feeding or grasping objects. Assistive devices
for stroke patients have been developing since a very long time
ago; however, some of them are not well accepted by patients
because they are not comfortable, wearable, portable, lightweight
and useful. This research presents the first version of the design
of dynamic orthosis to aid post-stroke patients with hemiplegia
to grasp cylindrical and spherical objects. The proposed orthosis
was designed by using a cyclic design methodology called Iterative
Design which is used for continuous product improvement;
moreover, this paper presents a detailed description of the
control algorithm and the electromechanical design in which a
flexible power transmission element was introduced to perform
the opening and closing of the hand. Then, a motion study
was performed to determine the range of motion (ROM) of
the orthosis. Results show that the orthosis is able to cover
88.8% of the ROM of the metacarpophalangeal (MCP) joint
and 72.7% of the ROM of the proximal interphalangeal (PIP)
joint. These results indicate that the hand orthosis can assist
patients in performing grasping tasks. In addition, the main
feature of this orthosis is ergonomic because it was designed
using anthropometric measurements of the hand. Other features
of the orthosis are lightweight (230 g), portable and easy to use.
Index Terms—stroke, hemiplegia, assistive device, hand ortho-
sis, dynamic orthoses, static orthoses
