Medical Robotics / Bio-Robotics
Elaheh Kafashi; Mohammad Ali Ahmadi Pajouh; Firooz Bakhtiari Nejad
Volume 14, Issue 4 , February 2021, , Pages 277-290
Abstract
Due to the high number of patients with cerebrovascular disease and stroke, which results in paralysis of organs on one side of the body, including the hand, as well as limitations in traditional rehabilitation methods, it is necessary to build devices to help these people. In this study, initially, ...
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Due to the high number of patients with cerebrovascular disease and stroke, which results in paralysis of organs on one side of the body, including the hand, as well as limitations in traditional rehabilitation methods, it is necessary to build devices to help these people. In this study, initially, given the challenges involved in designing an exoskeleton, the initial design was a mechanism for using it as a continuous passive motion to rehabilitate the fingers. This mechanism is tendon-based and covers both the flexion and extension of the fingers. For this purpose, two active and passive actuators have been used in the exoskeleton, respectively, to flex and extend the fingers. The distinctive feature of this design is its lightness, low volume, adjustability for different hands, compatibility, and comfort for the patient. Also, the kinematics and dynamics relationships modeled on the Lagrange method. The exoskeleton movement simulated in interaction with the finger with MATLAB sim-mechanics software. Finally, using simulation and modeling results, the final design was performed by considering the force of 40 N along the tendon, the exoskeleton made for the index finger. Also, the results of analytical modeling and simulation compared; the error rate of modeling obtained. In the worst case, this value was 15% for the first and second finger joints and 20% for the third joint.
Seyedeh Somayeh Naghibi; Ali Fallah; Ali Maleki; Farnaz Ghassemi
Volume 13, Issue 3 , October 2019, , Pages 247-257
Abstract
The correct prediction of the optimal motor trajectory is necessary for movement rehabilitation and control systems such as functional electrical stimulation and robotic therapy. It seems that human reaching movements are composed of a set of submovements, each of which is a correction of the overall ...
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The correct prediction of the optimal motor trajectory is necessary for movement rehabilitation and control systems such as functional electrical stimulation and robotic therapy. It seems that human reaching movements are composed of a set of submovements, each of which is a correction of the overall movement trajectory. Therefore, it is possible to interpret complex movements, learning, adaptability and other features of the motion control system using submovements. The purpose of this study is predicting and generating planar reaching movements using a realistic model similar to the actual mechanism of human movement and based on the submovement. The data used consists of different replications of four types of planar movement Performed by three healthy subjects. After the preprocessing and phasing, the movements decomposed to minimum-jerk submovement. In the next step, the training of three distinct neural networks was carried out to learn the submovement parameters including the amplitude, duration, and initiation time. Finally, the ANNs were combined to form a closed-loop model that generated accurate reaching movements based on the error correction. The target access rate for all predicted movements by the closed loop model was 100%. Also, the mean distance to the target, the VAF, and the mean MSE error between the predicted and main movement trajectory showed that the predicted movements are a good approximation of the main movements. The results showed that when trained neural networks with submovements, were placed in a closed loop model, they were able to predict proper submovements for complete access to targets due to the compensation of propagated errors from the previous steps. The results of this study can be used to improve motor rehabilitation methods.
Orthotics & Prosthesis
Rouhollah Sameri Nedafi; Ali Moazemi Goudarzi; Alireza Fathi
Volume 9, Issue 3 , December 2015, , Pages 305-316
Abstract
Abstract: The statistical studies indicate that diseases, accidents and wares are the principal causes to increase the number of amputees in the world. These studies also show that the most of mutilation disabilities are related to musculoskeletal. Obesity, sedentary, lack of proper exercise as well ...
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Abstract: The statistical studies indicate that diseases, accidents and wares are the principal causes to increase the number of amputees in the world. These studies also show that the most of mutilation disabilities are related to musculoskeletal. Obesity, sedentary, lack of proper exercise as well as the risk of some diseases, cause weaken in knee muscles and other difficulties of this hand. As a consequence, the knee muscles can`t apply a mighty torque to accomplish knee motion.The objective of this study is to propose a proper solution to improve the life quality of those who suffer from weak knees. In this study, by investigating the biomechanical behavior of a healthy foot in a normal gait, the indispensable power which can enforce a 50% weak Knee to achieve the same gait can be calculated. In order to naturalize the mentioned knee, a new control-active orthosis is designed. The proposed design is specified by an electromechanical actuator and an elastic component articulated in a light weight four-bar mechanism. Its mechanical behavior is tested in a simulated walking gait and the optimum value of elastic coefficient is estimated as 7KN/m. In this case, the maximum torque applicable to knee joint has increased by 34 per cent.
