11/30/2023 0 Comments Incontrol medical electrodeĪ control scheme in myoelectric prosthesis translates the information contained in the EMG signal to control command for actuation of prosthetic devices. The operation of smart EMG based prosthesis, working as an artificial substitute to missing limbs, is affected by numerous factors like change in position of the electrode, variation in the level of muscle contraction, the positioning of the forearm and limb orientation. The myoelectric prosthesis mainly consists of a device for capturing EMG signal, a controller for processing these signals and generating a control command in real-time to drive actuator mechanically linked with the prosthetics. A finely machined toothed silver electrode was developed for acquiring EMG signal, which showed performances similar to gelled type electrode and better than flat silver surface. proposed dry flexible electrodes and compared its performance with the commercial Ag/AgCl electrodes for detecting muscle contractions under different loading conditions. Although these electrodes may have higher skin–electrode impedance and susceptible to motion artifacts, however, there is a possibility of getting stronger sEMG signal with these electrodes. Dry electrodes, on the other hand, do not require gel as well as skin preparation procedure reducing time and effort to set up. These limitations make the wet electrodes unsuitable for the prosthetic application. Moreover, these require skin preparation, which increases the time and cost of measurement. These electrodes may cause irritations and allergies to skin, and their long-time use can degrade the quality of the signal because gel in the electrode dries with time. Silver–silver chloride (Ag/AgCl) is a wet type electrode which provides good signal quality and low electrode–skin impedance, but have some limitations also. These are categorized into wet and dry type electrodes. Surface myoelectrodes give the basic assessment of the EMG signal under the skin. A single-channel sEMG is sufficient to detect different activations of upper-limb muscles for numerous applications in rehabilitation and human–computer interface (HCI). Nowadays, sEMG has been established as a primary source of control for prosthetic hands due to their ease and intuitiveness. The precise measurement and analysis of sEMG signals are utilized in various applications that include clinical diagnosis of neuromuscular disorders, the study of muscle fatigue, and control of prosthetics. It is usually preferred because it is painless and quite easy to acquire. Surface electromyography (sEMG) is a non-invasive technique for the assessment of the myoelectric signal. With proportional control scheme, the myoelectric hand setup was able to provide quicker and delicate grasping of objects as per the strength of the EMG signal. The sEMG sensor was further tested on amputees to control the operation of a self-designed 3D printed prosthetic hand. Also, the proposed sensor was 57% faster than the commercial sensor in producing the output response. The results showed 1.4 times greater SNR values and 45% higher sensitivity of the developed sensor than the commercial EMG sensor. To perform this, EMG data with both devices were recorded for 10 subjects (3 amputees and 7 healthy subjects). The output performance of the developed sensor was compared with commercial EMG sensor regarding signal-to-noise ratio, sensitivity, and response time. The envelope detection technique in the sensor based on the tuned RC parameters enables the generation of smooth, faster, and repeatable EMG envelope irrespective of signal strength and subject variability. The performance of dry electrodes employed in the skin interface was compared with the conventional Ag/AgCl electrodes, and the results were found satisfactory. The sensor consists of an electrode interface, signal conditioning unit, and power supply unit all encased in a single package. This paper proposes a compact and affordable EMG sensor for the prosthetic application. The main problems with the presently available EMG devices are their extremely high cost, large response time, noise susceptibility, less amplitude sensitivity, and larger size. Myoelectric prosthesis requires a sensor that can reliably capture surface electromyography (sEMG) signal from amputees for its controlled operation.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |