Exoskeleton robots for upper-limb rehabilitation
ABSTARCT :
In this paper, the design of a new upper limb rehabilitation system is presented. The developed system is an exoskeleton with two degrees of freedom that can be used for diagnosis, physical therapy, and outcome evaluation. The system is dedicated to the patients with paraplegia of their upper extremities due to stroke or any disorders of the central or peripheral nervous system. The designed robot-aided therapy actuates both movements: flexion/extension for the elbow and pronation/supination for the forearm. The robotic system used Kinects skeletal tracking for an upper limb rehabilitation. Position control is communicated via a wireless network. Indeed a ZigBee protocol using xbee communication modules has been installed to ensure remote control of rehabilitation exercise. A kinematic model has been developed based on Denavit-Hartenberg approach to make first tests. A sliding mode robust law control has been implemented. The Lyapunov-based approach has been used to establish the system asymptotic stability. Experimental results are provided to demonstrate performances of the developed robot of upper limb remote rehabilitation.
EXISTING SYSTEM :
? In particular, the all-round comparisons of existing rehabilitation robots are based on the published available data, to make researchers fully aware of the limitations and advantages of diverse mechanical designs and control schemes.
? The existing problems of upper limb rehabilitation robots are presented in this paper.
? The end-effector-based upper limb rehabilitation robots (such as MIT-Manus, MIME) have the advantages of simple structure, easy carrying, simple control method, easy trajectory planning, etc., applying force to the patient's hand to pull upper limbs.
? However, the exoskeleton style requires that the mechanical joint axis and the human body joint axis must coincide.
DISADVANTAGE :
? The BONES occupies five actuators to provide a wide range of motion for the upper limb and further measurements for safety issues.
? The disadvantage is that it is limited to two-dimensional space and it can not provide more training assistance to the upper limbs.
? This paper analyzes some the upper limb rehabilitation robots and summarizes the problems in the structural design of these rehabilitation robots.
? Many of these innovations were technology-driven, limiting their clinical application and impact.
? A positive impact on outcome of function, rehabilitation approaches should be based on neurophysiological and clinical insights, keeping in mind that recovery of function is limited.
PROPOSED SYSTEM :
• The proposed exoskeleton robot depends on the extracted EMG signal to perform the limb’s motions.
• The proposed exoskeleton rehabilitates the impaired limb by providing different angular velocities in addition to variations in impedance.
• The proposed system, however, has its own limitations, such as its size and weight, in addition to its poor attachment.
• The movement of the upper limb of the patient is assisted by the robot to achieve the purpose of rehabilitation training.
• The training of cooperative hand movements (e.g. opening a bottle) has been proposed using a dedicated device, and can also be achieved by virtually coupling two unimanual devices through control.
ADVANTAGE :
? The performance was judged based on timing and smoothness. While the training session consisted of goal direct reaching movement performed by the subject.
? The performance and the recovery of the patients would suffer if the patient is not motivated and/or satisfied with the robotic rehabilitation.
? Clinical studies have used different devices, training protocols and evaluation criteria to judge the performance of robotic device on impairment reduction.
? The advantage of the end-effector-base robot is that the structure is simple and portable, the control method is simple and the trajectory planning is easy.
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