Our goal is to enhance the quality of life of patients with hemiplegia by means of an active motion support system that assists the impaired motion such as to make it as close as possible to the motion of an able bodied person. We have developed the Robot Suit HAL (Hybrid Assistive Limb) to actively support and enhance the human motor functions. The purpose of the research presented in this paper is to propose the required control method to support voluntarily motion using a trigger based on patient’s bioelectrical signal. Clinical trials were conducted in order to investigate the effectiveness of the proposed control method. The first stage of the trials, described in this paper, involved the participation of one hemiplegic patient who is not able to bend his right knee. As a result, the motion support provided by the HAL moved the paralyzed knee joint according to his intention and improved the range of the subject’s knee flexion. The first evaluation of the control method with one subject showed promising results for future trials to explore the effectiveness for a wide range of types of hemiplegia.

Категория: Ищем научные статьи | Нет комментариев »

This article presents a wearable lower extremity exoskeleton (LEE) developed to enhance the ability of a human’s walking while carrying heavy loads. The ultimate goal of the current research work is to design and control a power assist system that integrates a human’s intellect for feedback and sensory purposes. The exoskeleton system in this work consists of an inner exoskeleton and an outer exoskeleton. The inner exoskeleton measures the movements of the wearer and provides these measurements to the outer exoskeleton, which supports the whole exoskeleton system to walk following the wearer. A special footpad, which is designed and attached to the outer exoskeleton, can measure the zero moment point (ZMP) of the human as well as that of the exoskeleton in time. Using the measured human ZMP as the reference, the exoskeleton’s ZMP is controlled by trunk compensation so that the exoskeleton can walk stably. A simulation platform has first been developed to examine the gait coordination through inner and outer exoskeletons. A commercially available software, xPC Target, together with other toolboxes from MATLAB, has then been used to provide a real-time operating system for controlling the exoskeleton. Real-time locomotion control of the exoskeleton is implemented in the developed environment. Finally, some experiments on different objects showed that the stable walking can be achieved in the real environment.

Категория: Ищем научные статьи | Нет комментариев »

In this study, the sliding mode approach is applied to the tracking control problem of a planar arm manipulator system driven by a new type of actuator, which comprises a pneumatic muscle (PM) and a torsion spring. Unlike the traditional agonist/antagonist PM actuator, the PM is arranged in place of bicep and the torsion spring provides opposing torque in the presented actuator. The dynamic model is derived for this system and a sliding mode controller is designed to make the joint angle track a desired trajectory within a guaranteed accuracy even there are modelling uncertainties. A selection method is also proposed to obtain an appropriate spring coefficient, which plays an important role in the tracking control task. The effectiveness of the proposed method is confirmed by simulations. The differences between the control results of using our new actuator and that of using the traditional PM actuator in opposing pair configuration are also compared.

Категория: Ищем научные статьи | Нет комментариев »

This paper is aimed at developing a smart actuator for assistive knee braces to provide assistance to disabled or elderly people with mobility problems. A magnetorheological (MR) actuator is developed to be used in assistive knee braces to provide controllable torque. The MR actuator can work as a brake or a clutch. When active torque is needed, the DC motor works and the MR actuator functions as a clutch to transfer the torque generated by the motor to the leg; when passive torque is desired, the DC motor is turned off and the MR actuator functions as a brake to provide controllable passive torque. The prototype of the developed MR actuator is fabricated and experiments are carried out to investigate the characteristics of the MR actuator. The results show that the MR actuator is able to provide sufficient torque needed for normal human activities. Adaptive control is proposed for controlling the MR actuator. Anti-windup strategy is used to achieve better control performance. Experiments on the MR actuator under control are also performed to study the torque tracking ability of the system.

Категория: Ищем научные статьи | 40 комментариев »

The Journal of Engineering in Medicine is an interdisciplinary journal encompassing all aspects of engineering in medicine. The Journal is a vital tool for maintaining an understanding of the newest techniques and research in medical engineering.

Категория: Ищем научные статьи | Нет комментариев »