Estimation of EMG-Based force using a neural-network-based approach

© 2013 IEEE. The dynamics of human arms has a high impact on the humans' activities in daily life, especially when a human operates a tool such as interactions with a robot with the need for high dexterity. The dexterity of human arms depends largely on motor functionality of muscle. In this sense, the dynamics of human arms should be well analyzed. In this paper, in order to analyse the characteristic of human arms, a neural-network-based algorithm is proposed for exploring the potential model between electromyography (EMG) signal and human arm's force. Based on the analysis of force for humans, the mean absolute value of the electromyographic signal is selected as the input for the potential model. In this paper, in order to accurately estimate the potential model, three domains fuzzy wavelet neural network (TDFWNN) algorithm without prior knowledge of the biomechanical model is utilized. The performance of the proposed algorithm has been demonstrated by the experimental results in comparison with the conventional radial basis function neural network (RBFNN) method. By comparison, the proposed TDFWNN algorithm provides an effective solution to evaluate the influence of human factors based on biological signals

Estimation and Early Prediction of Grip Force Based on sEMG Signals and Deep Recurrent Neural Networks

Hands are used for communicating with the surrounding environment and have a complex structure that enables them to perform various tasks with their multiple degrees of freedom. Hand amputation can prevent a person from performing their daily activities. In that event, finding a suitable, fast, and reliable alternative for the missing limb can affect the lives of people who suffer from such conditions. As the most important use of the hands is to grasp objects, the purpose of this study is to accurately predict gripping force from surface electromyography (sEMG) signals during a pinch-type grip. In that regard, gripping force and sEMG signals are derived from 10 healthy subjects. Results show that for this task, recurrent networks outperform nonrecurrent ones, such as a fully connected multilayer perceptron (MLP) network. Gated recurrent unit (GRU) and long short-term memory (LSTM) networks can predict the gripping force with R-squared values of 0.994 and 0.992, respectively, and a prediction rate of over 1300 predictions per second. The predominant advantage of using such frameworks is that the gripping force can be predicted straight from preprocessed sEMG signals without any form of feature extraction, not to mention the ability to predict future force values using larger prediction horizons adequately. The methods presented in this study can be used in the myoelectric control of prosthetic hands or robotic grippers.Comment: 9 pages, accepted for publication in journal of the Brazilian Society of Mechanical Sciences and Engineerin

Interaction Motion Control on Tri-finger Pneumatic Grasper using Variable Convergence Rate Prescribed Performance Impedance Control with Pressure-based Force Estimator

Pneumatic robot is a fluid dynamic based robot system which possesses immense uncertainties and nonlinearities over its electrical driven counterpart. Requirement for dynamic motion handling further challenged the implemented control system on both aspects of interaction and compliance control. This study especially set to counter the unstable and inadaptable proportional motions of pneumatic robot grasper towards its environment through the employment of Variable Convergence Rate Prescribed Performance Impedance Control (VPPIC) with pressure-based force estimation (PFE). Impedance control was derived for a single finger of Tri-finger Pneumatic Grasper (TPG) robot, with improvement being subsequently made to the controller’s output by appropriation of formulated finite-time prescribed performance control. Produced responses from exerted pressure of the maneuvered pneumatic piston were then recorded via derived PEE with adherence to both dynamics and geometry of the designated finger. Validation of the proposed method was proceeded on both circumstances of human hand as a blockage and ping-pong ball as methodical representation of a fragile object. Developed findings confirmed relatively uniform force sensing ability for both proposed PEE and load sensor as equipped to the robot’s fingertip with respect to the experimented thrusting and holding of a human hand. Sensing capacity of the estimator has also advanced beyond the fingertip to enclose its finger in entirety. Whereas stable interaction control at negligible oscillation has been exhibited from VPPIC against the standard impedance control towards gentle and compression-free handling of fragile objects. Overall positional tracking of the finger, thus, justified VPPIC as a robust mechanism for smooth operation amid and succeed direct object interaction, notwithstanding its transcendence beyond boundaries of the prescribed performance constraint

Knee Joint Competence Post Anterior Cruciate Ligament Reconstruction in Amateur South Western Districts Rugby Players

Background: Globally, literature has shown that rugby players struggle to return to the same level of performance post anterior cruciate ligament (ACL) reconstruction. This phenomenon is further exacerbated amongst South African Rugby players, compounded by the ranking of the national team amongst the top ten rugby teams worldwide. Paired with the psychosocial aspect of return to play, the physical and physiological competence of the knee joint is of pivotal importance. Purpose: To compare relative dynamic stability scores paired with electromyography (EMG) scores between the injured and uninjured legs, thereby enabling an explorative, descriptive report on dynamic proprioceptive abilities post ACL reconstruction (ACLR). The study findings therefore aim to inform rehabilitative practice in a rugby player who underwent ACLR. Study Design: A quantitative, explorative and descriptive design was used, with a purposive sampling strategy. Methods: Biographical and anthropometrical data was measured upon inception. Muscular activation was measured using electromyography (EMG) placements on quadriceps muscles which included the vastus medialis obliques (VMO), and vastus lateralis (VL). Dynamic proprioception was measured using the star excursion balance test (SEBT) and normalised to leg length. A neuromuscular fatigue protocol was used to measure the impact of neuromuscular fatigue on dynamic stability, and muscle activation between the injured and uninjured lower limbs. Results: A sample of 15 participants from the South Western Districts (SWD) rugby team, fitting the inclusion criteria, were included in the study. The average age was 27±2.7 years. The results indicated that fatigue did not significantly affect the SEBT scores between the injured and uninjured lower limbs. However, the VMO muscle activation showed a statistically significant difference in muscle firing in a pre-fatigue state. This difference was evident in two of the eight directions namely anteromedial direction (p = 0.041), and in the lateral direction (p = 0.047). Furthermore, these result differences were favoured in the uninjured limb. No significant differences between the injured and uninjured lower limbs were found in respect to VMO and VL muscle activation, in a fatigued state. vi Conclusion: Practically translated, the study results showed that the injured lower limb, showed no significant differences in dynamic stability during both the non-fatigued and the fatigued SEBT. Therefore, the finding of this study is a steppingstone towards informing return to play criteria for adequate dynamic knee stability and proprioception. It should be noted that further research is necessary to refine return to play criteria and thereby decrease the risk for re-injury. Keywords: anterior cruciate ligament; dynamic stability; neuro-muscular fatigue; reconstruction; re-injury; return-to-sport; rugby.Thesis (MA) -- Faculty of Health Sciences, 202

Knee Joint Competence Post Anterior Cruciate Ligament Reconstruction in Amateur South Western Districts Rugby Players

Background: Globally, literature has shown that rugby players struggle to return to the same level of performance post anterior cruciate ligament (ACL) reconstruction. This phenomenon is further exacerbated amongst South African Rugby players, compounded by the ranking of the national team amongst the top ten rugby teams worldwide. Paired with the psychosocial aspect of return to play, the physical and physiological competence of the knee joint is of pivotal importance. Purpose: To compare relative dynamic stability scores paired with electromyography (EMG) scores between the injured and uninjured legs, thereby enabling an explorative, descriptive report on dynamic proprioceptive abilities post ACL reconstruction (ACLR). The study findings therefore aim to inform rehabilitative practice in a rugby player who underwent ACLR. Study Design: A quantitative, explorative and descriptive design was used, with a purposive sampling strategy. Methods: Biographical and anthropometrical data was measured upon inception. Muscular activation was measured using electromyography (EMG) placements on quadriceps muscles which included the vastus medialis obliques (VMO), and vastus lateralis (VL). Dynamic proprioception was measured using the star excursion balance test (SEBT) and normalised to leg length. A neuromuscular fatigue protocol was used to measure the impact of neuromuscular fatigue on dynamic stability, and muscle activation between the injured and uninjured lower limbs. Results: A sample of 15 participants from the South Western Districts (SWD) rugby team, fitting the inclusion criteria, were included in the study. The average age was 27±2.7 years. The results indicated that fatigue did not significantly affect the SEBT scores between the injured and uninjured lower limbs. However, the VMO muscle activation showed a statistically significant difference in muscle firing in a pre-fatigue state. This difference was evident in two of the eight directions namely anteromedial direction (p = 0.041), and in the lateral direction (p = 0.047). Furthermore, these result differences were favoured in the uninjured limb. No significant differences between the injured and uninjured lower limbs were found in respect to VMO and VL muscle activation, in a fatigued state. vi Conclusion: Practically translated, the study results showed that the injured lower limb, showed no significant differences in dynamic stability during both the non-fatigued and the fatigued SEBT. Therefore, the finding of this study is a steppingstone towards informing return to play criteria for adequate dynamic knee stability and proprioception. It should be noted that further research is necessary to refine return to play criteria and thereby decrease the risk for re-injury. Keywords: anterior cruciate ligament; dynamic stability; neuro-muscular fatigue; reconstruction; re-injury; return-to-sport; rugby.Thesis (MA) -- Faculty of Health Sciences, 202

XIV Conference on Technology, Teaching and Learning of Electronics

Livro de atas da TAEE2020.A conferencia TAEE conhecerá na sua 14ª edição um momento histórico. Não só é a primeira vez que a será organizada fora do território Espanhol, como terá lugar a verdadeiramente pioneira experiência de realizar esta conferência num formato puramente virtual no Instituto Superior de Engenharia do Porto. Esta opção representa a solução possível para um evidente problema mundial, que surgiu de forma repentina durante a preparação desta edição. Optamos por aplicar a típica abordagem de engenharia, instintivamente encarando este novo problema como uma verdadeira oportunidade, e aproveitando as limitações impostas para experimentar novas soluções para novas questões. Tentamos criar uma TAEE diferente, não melhor nem pior, mas indo buscar proveitos às tecnologias de comunicação emergentes de forma a criar e dinamizar um evento onde não estaremos fisicamente juntos, mas poderemos comunicar e conviver de forma virtual. A grande motivação da TAEE será sempre os visíveis entrosamentos, dedicação e motivação da comunidade e serão estes fatores que permitirão o sucesso nesta nova forma de estarmos e trabalharmos juntos, mas à distância.info:eu-repo/semantics/publishedVersio