Forward Kinematic and Jacobian Matrix for the Prosthetic Human Finger Actuated by Links

The most important function of a prosthetic hand is their ability to perform tasks in a manner similar to a natural hand, so it is necessary to perform kinematic analysis to determine the performance and the ability of the prosthetic human finger design to work normally and smoothly when it's drive by two sets of links that embedded in its structure and pulled by a servomotor, so the Denvit-Hartenberg method was used to analyse the forward kinematics for the prosthetic finger joints to deduction the trajectory of the fingertip and the velocity of the joints was computed by using the Jacobian matrix. The prosthetic finger was modelled by the Solidwork - 2018 program and the results of kinematics were verified using MATLAB. The analyses that were conducted on the design showed that the designed prosthetic finger has the ability to perform movements and meets the functional requirements for which it is designed.

Monitoring of Beech Glued Laminated Timber and Delamination Resistance of Beech Finger-Joints in Varying Ambient Climates

In this study, varying ambient climates were simulated in a test building by changing temperature and relative humidity. Beech glued laminated timber (glulam, Fagus sylvatica, L.) was freshly installed in the test building and monitoring of the change in wood moisture content of the glulam resulting from the variations in climate was carried out. Subsequently, finger-jointed beech specimens were exposed to the variations in relative humidity measured in the course of the monitoring experiment on a laboratory scale, and thus an alternating climate regime was derived from the conditions in the test building. Its influence on the delamination of the finger-joints was evaluated. In addition, it was examined whether beech finger-joints using commercial adhesive systems fulfil the normative requirements for delamination resistance according to EN 301 (2018) and whether different bonding-wood moisture levels have an effect on the delamination of the finger-joints. In the context of the monitoring experiment, there was a clear moisture gradient in the beech glulam between the inner and near-surface wood. The applied adhesive systems showed almost the same delamination resistance after variation of relative humidity. The normative requirements were met by all PRF-bonded and by most PUR-bonded beech finger-joints with higher bonding wood moisture content.

Finger-jointing of green Eucalyptus globulus L. wood with one-component polyurethane adhesives

The use of glued finger joint in green wood, directly from the sawing process, would open the possibility to obtain glued timber from small-sized wood, achieving an efficient use of the original raw material. The gluing of finger-jointed green wood, with moisture content above the fibre saturation point, may improve the efficiency and the manufacturing process of glulam or joinery. This may be especially beneficial for a hardwood such as Eucalyptus globulus L., which is a globally important forest resource, but is a challenging wood to dry. This article presents a study on the possibility to develop finger joints with wood in green state. To compare them, conventional finger joints on dry wood and solid boards without end joints were also manufactured. Cold-setting and fast-curing commercial one-component polyurethane adhesive systems were used. Finger-jointed samples were tested to determine mean and characteristic values (5th percentile) of density, bending strength and modulus of elasticity, and the results were analysed and discussed. Green-glued joints showed no statistically significant differences compared to the solid boards and improved strength properties with respect to dry-glued joints.

Problematic Issues of the Theory and Practice of Finger Joints Endoprosthetics (Literature Review)

Summary. The proximal interphalangeal and metacarpophalangeal joints play an important role in the function of the hand as an organ of labor and self-care. The frequency of joint injuries of this localization reaches 32% in the structure of hand injuries, and unsatisfactory consequences are associated with the severity of the injury. Wrong treatment ranges between 60-80%, which gives ground to classify the problem as socially significant. The development and improvement of implant designs came through the introduction of new materials, structural changes in the fasteners and mobility. Much of the implants design became a thing of the past, giving a push to the development of new models. The need for anatomical and functional compliance of the implant with the characteristics of a healthy joint gave an impulse to research on the manufacture of individual prostheses with the help of 3D modeling. The analysis of literature sources showed a high level of unfavorable consequences of damage to the finger joints and the prospects for the development of more anatomical designs of hand joints prostheses. The development of individual geometrically similar designs endoprostheses of the finger joints of hand that will provide conditions of improvement of quality of treatment of patients remains an actual problem. The relatively short period of operational suitability of existing endoprostheses affected by a limited number of medical supervision necessitates the expansion of research in the near and long terms after prosthetics.

Identifying discriminative features for diagnosis of Kashin-Beck disease among adolescents

Introduction Diagnosing Kashin-Beck disease (KBD) involves damages to multiple joints and carries variable clinical symptoms, posing great challenge to the diagnosis of KBD for clinical practitioners. However, it is still unclear which clinical features of KBD are more informative for the diagnosis of Kashin-Beck disease among adolescent. Methods We first manually extracted 26 possible features including clinical manifestations, and pathological changes of X-ray images from 400 KBD and 400 non-KBD adolescents. With such features, we performed four classification methods, i.e., random forest algorithms (RFA), artificial neural networks (ANNs), support vector machines (SVMs) and linear regression (LR) with four feature selection methods, i.e., RFA, minimum redundancy maximum relevance (mRMR), support vector machine recursive feature elimination (SVM—RFE) and Relief. The performance of diagnosis of KBD with respect to different classification models were evaluated by sensitivity, specificity, accuracy, and the area under the receiver operating characteristic (ROC) curve (AUC). Results Our results demonstrated that the 10 out of 26 discriminative features were displayed more powerful performance, regardless of the chosen of classification models and feature selection methods. These ten discriminative features were distal end of phalanges alterations, metaphysis alterations and carpals alterations and clinical manifestations of ankle joint movement limitation, enlarged finger joints, flexion of the distal part of fingers, elbow joint movement limitation, squatting limitation, deformed finger joints, wrist joint movement limitation. Conclusions The selected ten discriminative features could provide a fast, effective diagnostic standard for KBD adolescents.

Robotic Hands a Base for Prosthetics - A Review

This review paper reports the findings of previously designed robotic hand and summarizes the advantages and limitations for modeling a robotic hand and proposes methods to overcome the limitations of the previously designed hand models. A robotic hand forms its base by mimicking the structure and motions of a Human hand and all studies are focused on improving the current models to have similar dexterity as of the human hand. Many Robotic hands have been created to mimic the human hand functions and gestures but they still lack the dexterity, compactness or affordability for prosthetic use. In this paper we have reviewed recently designed rigid robotic hands having rotating finger joints and soft robotic tendon actuated hands that use a single elastic block to create the whole finger so to reduce the rotating finger joints after reviewing the designs we have compiled a set of points that can be used as the framework for a design that can overcome the limitations of the previous designs.

Silicone and Pyrocarbon Artificial Finger Joints

Artificial finger joint design has been developed through different stages through the past. PIP (proximal interphalangeal) and MCP (metacarpophalangeal) artificial finger joints have come to replace the amputation and arthrodesis options; although, these artificial joints are still facing challenges related to reactive tissues, reduced range of motion, and flexion and extension deficits. Swanson silicone artificial finger joints are still common due to the physician’s preferability of silicone with the dorsal approach during operation. Nevertheless, other artificial finger joints such as the pyrocarbon implant arthroplasty have also drawn the interests of practitioners. Artificial finger joint has been classified under three major categories which are constrained, unconstrained, and linked design. There are also challenges such as concerns of infections and articular cartilage necrosis associated with attempted retention of vascularity. In addition, one of the main challenges facing the silicone artificial finger joints is the fracture occurring at the distal stem with the hinge. The aim of this paper is to review the different artificial finger joints in one paper as there are few old review papers about them. Further studies need to be done to develop the design and materials of the pyrocarbon and silicone implants to increase the range of motion associated with them and the fatigue life of the silicone implants.