engleski

Innovative mechatronics device for upper limb rehabilitation

INTRODUCTION: Impaired arm movements, a frequent consequence of stroke as the leading cause of disability in the developed countries, but also of muscle atrophy and dystrophy conditions, imply an increasing need for physical rehabilitation. The insufficient number of physical therapists coupled to the time-intensive traditional therapeutic procedures, whose progress and efficiency is often hard to follow and assess, are a limiting factor in this regard. This has recently prompted the development of mechatronics rehabilitation devices that not only enable the achievement of a large number of adaptively assisted movements, but also allow a single therapist to assist concurrently three patients. However, the commercially available devices are expensive and capacious, while their adaptability to the personalised rehabilitation needs is limited. AIMS: The aim of this works is to design an advanced mechatronics arms’ rehabilitation device that is versatile and allows an increased range of assisted arms’ movements, but also portable, efficient and cost-effective, providing high intensity and frequency treatments. The device will enable coordinated arms’ movements assisted by actuating devices whose power contribution depends on the level of the autonomous effort provided by the patient, as well as on suitable sensing elements and a complementing control architecture. METHODS: A crucial task in designing versatile rehabilitation devices is the study of the anatomy and kinematics of arms’ movements. In recent literature, it was shown that a structure with seven degrees-of-freedom (DOFs) can assure a good combination of motion accuracy and acceptable device complexity. The coordinated use of the DOFs of the designed assistive mechatronics device is hence based on inverse arms’ kinematics, i.e., on the conversion of the position and orientation of manipulator’s end- effector from Cartesian space to the DOFs of the used servo actuators. A geometric approach based on the rotation matrices in Euclidean space and the Denavit-Hartenberg parameters, which allow simplifying the considered kinematics via coordinate transformations in a single homogeneous transformation matrix, is hence employed and implemented in the Matlab/Simulink environment. Based on these considerations, electronics components (actuators with power supplies and feedback sensors) fitting the characteristics of the resulting mechanism are chosen, while an appropriate simultaneous real- time control system is being developed. What is more, the device will be mainly based on 3D printing passive components that enable its easy reconfiguration according to the needs of the single patients, while assuring its reduced weight and space requirements. RESULTS AND CONCLUSIONS: The design of all the elements of the prototype of the innovative mechatronics device presented in this work will enable a highly efficient rehabilitation of the patients with reduced functionality of upper limbs. The concept will enable the control and insight in the active recovery process of the patients with an explicit reduction of the waiting times for the recovery procedures. What’s more, a further development expanding its architecture with a virtual reality interface, will allow boosting the patients’ motivation, which should lead to an even faster and more efficient recovery, i.e., the fast return to everyday activities.

arm rehabilitation, mechatronics device, innovative design, inverse kinematics parameters

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