DESIGN, DYNAMIC MODELING AND CONTROL OF WEARABLE FINGER ORTHOSIS

Human hands and fingers are of significant importance in people’s capacity to perform daily tasks (touching, feeling, holding, gripping, writing). However, about 1.5 million people around the world are suffering from injuries, muscle and neurological disorders, a loss of hand function, or a few fingers due to stroke. This paper focuses on newly developed finger orthotics, which is thin, adaptable to the length of each finger and low energy costs. The aim of the study is to design and control a new robotic orthosis using for daily rehabilitation therapy. Kinematic and dynamic analysis of orthosis was calculated and the joint regulation of orthosis was obtained. The Lagrange method was used to obtain dynamics, and the Denavit–Hartenberg (D–H) method was used for kinematic analysis of hand. In order to understand its behavior, the robotic finger orthotics model was simulated in MatLab/Simulink. The simulation results show that the efficiency and robustness of proportional integral derivative (PID) controller are appropriate for the use of robotic finger orthotics.

Robotic Orthosis for Upper Limb Rehabilitation

Individuals with impaired upper limbs have motor limitations that interfere with functionality. An alternative to rehabilitation is robot-assisted therapy, a method that increases the effectiveness of treatment. New robotic actuators have been developed to assist in the rehabilitation of the upper limb. One of them aims to actively perform finger extension and flexion passively, using a servo motor coupled to a rope system. At the elbow, a direct current (DC) motor combined with a gearbox was coupled to a system of pulleys and ropes designed to actively perform flexion and extension movements. To activate the system, an Arduino-NANO® and a mobile application for Android were used. The performance of the prototype was evaluated in four post-stroke volunteers. The ability to perform the proposed movements with the device was observed. Structural reinforcement was necessary, after twisting the elbow support structure, with pronation of the forearm, resulting in increased component weight. This work presented new robotic devices that can assist in the rehabilitation of post-stroke individuals.

Development of a Robotic Hand Orthosis for Stroke Patient Rehabilitation

<p class="0abstractCxSpFirst">This study developed a robotic orthosis capable of detecting the intention of a wearer to move their fingers, thereafter augmenting their muscle force. This was with the aim of producing a device that can be used in post-stroke hand rehabilitation. The design of the orthosis was based on an existing design, which was modified using BLENDER release 2.78 and printed with ABS plastic. An actuator was mounted at the rear end of the orthosis, to provide actuation to perform full range flexion and extension motion for digits. Force sensors were embedded at the fingertips of the orthosis to detect minute finger movements. For severe cases where stroke survivors are incapable of little finger movements, the study employed a brain-computer interface to detect the intent to move. The robotic orthosis achieved an accuracy of 64.1% and 62% in detecting unclench and clench activities respectively and actuating the orthosis digits in response. The results revealed that the design presented here can help provide effective hand rehabilitation. The study concluded that the design incorporated with BCI systems is capable of performing hand rehabilitation in a clinical setting as it obtains some level of accuracy in detecting patient intent to move and actuating in response. This design is low cost, and hence will lessen the economic burden for stroke survivors in a poor-resource country.</p><p class="0abstractCxSpLast"><strong> </strong></p>

Evaluation of Commercial Ropes Applied as Artificial Tendons in Robotic Rehabilitation Orthoses

This study aims to present the design, selection and testing of commercial ropes (artificial tendons) used on robotic orthosis to perform the hand movements for stroke individuals over upper limb rehabilitation. It was determined the load applied in the rope would through direct measurements performed on four individuals after stroke using a bulb dynamometer. A tensile strength test was performed using eight commercial ropes in order to evaluate the maximum breaking force and select the most suitable to be used in this application. Finally, a pilot test was performed with a user of the device to ratify the effectiveness of the rope. The load on the cable was 12.38 kgf (121.4 N) in the stroke-affected hand, which is the maximum tensile force that the rope must to supports. Paragliding rope (DuPont™ Kevlar ® ) supporting a load of 250 N at a strain of 37 mm was selected. The clinical test proved the effectiveness of the rope, supporting the requested efforts, without presenting permanent deformation, effectively performing the participant’s finger opening.