More than 5,000 major limb amputations are carried out every year in the UK () . Amputees can then choose to use an artificial limb, such as a prosthetic hand in case of an upper limb loss. Traditional so-called passive prostheses look like a real hand, but cannot be moved. Within the last decades however, more sophisticated active myoelectric hand prostheses were developed: their fingers and joints can be moved and controlled using Electromyography (EMG). EMG records the myoelectric signal from electrodes on the surface of human skin which capture electrical activity of contracting muscles thereunder. Hence, the prosthesis can be controlled by the residual muscles that used to control the biological limb.
we use the following terms to refer to different stages of a grasping process for both natural and artificial hands: While the object is being approached, the hand takes on a preshape. This refers to such a shape of the fingers that allows to put the hand close to or around the object. The process of changing hand posture from the previous hand posture to this preshape is called preshaping and can be seen as a preparation for grasping. The process of approaching the object as far as possible with this preshaped hand is referred to as pregrasping. Preshaping and pregrasping constitute the pregrasp. Subsequently, some or all fingers are closed until the grip is adequately tight. This closing process will be called finalising the grasp in this dissertation; the hand posture resulting from this is the final grasp. Depending on the object, there might furthermore be a trigger available, which refers to a fast movement with one or two fingers to use a certain functionality of the object, e.g. to push a button. A grasp type can be seen as a set of a preshape, a final grasp and possibly an available trigger. For some objects, the final grasp could be reached from a neutral hand position directly. However, for more complex objects like those including handles, a preshape is necessary to get fingers into the right position before finalising the grasp. If preshape and final grasp were automatically triggered without a break in between, patients using prostheses might not have enough time to find an appropriate hand position before finalising the grasp. Therefore, the usual grasping procedure with an active prosthesis includes both a pregrasp and a final grasp.
Prosthetic Hand Design Project - YouTube
CIE-Hand is a prototype of hand prosthesis developed by . The Hand was designed and constructed as a part of master thesis by , and Grzegorz Sztylka.
It is projects like Open Hand Project, ..
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CIE Hand an EMG Controlled Hand Prosthesis Project
However, myoelectric signals are typically noisy and only few kinds of muscle activity can be recognised precisely. Therefore, only a limited number of commands can be used for control and the full potential of the robotic hand cannot be used. This project aims at extending the input space by camera input.
Partial Hand Prosthesis | O&P Virtual Library
The objective of my project is to develop a myoelectric hand prosthesis which is more affordable for patients, when compared to the ones that can be found nowadays on the market (30,000 to 100,000€). The method to achieve the goal consists of re-conceptualizing and simplifying the conventional prosthesis, trying to look for inspiration in nature and new technologies.
UNC student creates prosthetic hand for youngster
In order to deal with the EMG-related issues we propose a semi-autonomous way of choosing the pre-grasp. A simple vision-based system is investigated, where a camera mounted on the prosthesis captures the image of the desired object to be grasped and the hand automatically chooses and executes the suitable pre-grasp without any interference of the patient. Fast recognition is succeeded by using QR codes to label the objects that are used in our experiment.
The only thing the patient needs to control is the transportation of the hand in a way that aligns it with the desired object and triggering the closing and opening of the fingers around the object, via electromyography techniques. We suggest that a vision-based system is more intuitive and allows the user to utilize all the available functionalities of the hand.