Effects of introducing a parametric Cad in a first year course in engineering degree regarding quality of technical drawings

Comunicació presentada al ICERI 2019 12th annual International Conference of Education, Research and Innovation (Seville, Spain. 11-13 November, 2019).The evolution of teaching in technical drawing during the last years has been addressed towards new paradigms based on 3D modeling. Nevertheless, not only 3D modeling skills are important for an engineer, but the ability to generate quality technical drawings also are part of the learning objectives and should, therefore, be included in the curriculum. For several years, the core subject of technical drawing at Universitat Jaume I has been a common subject during the first course of different Engineering bachelor’s degrees (Mechanical, Industrial Technologies, Electrical, Chemical, and Agrifood/Rural). However, in the last two years, the subject in the case of Agrifood Engineering has been taught independently. This course, aiming for a more intuitive introduction to 3D modeling, the subject has experienced a general methodological change for all the degrees, except for the Agrifood Engineering one. Apart from changing the order of contents with the intention of improving spatial vision, the use of a different commercial CAD software was implemented, this being parametric. In a previous work, the effect of this general methodological change was assessed through the academic performance regarding 3D modeling by comparing the scores before and after implementing the change, as well as through specific questionnaires addressed to students and teachers, obtaining very positive results. Notwithstanding, the effects of the change performed on the obtainment of technical drawings were not analyzed. Taking advantage of having two groups (the one that has experienced the change and the one that did not), they were asked to model and generate the drawing of the same parts in their final exams, with the aim of comparing the scores obtained when assessing their skills of modeling, but also in creating technical drawings (views, sections and dimensioning) and in the quality on technical drawings presentation (title block, line thickness, etc.). Scores were collected and statistical analyses were performed, bringing to light that despite the good results that were obtained in previous studies regarding the 3D modeling, teaching efforts in how to generate technical drawings with quality should be reinforced in future

Kinetic and kinematic analysis of midfoot joints of healthy subjects during walking: Clinical considerations

Introducción: No existe todavía suficiente evidencia en estudios clínicos respecto al comportamiento del mediopié en situaciones dinámicas como la marcha o la carrera. El presente estudio pretende analizar el comportamiento mecánico de las articulaciones del mediopié mediante un modelo multisegmental del pie, con especial atención a los momentos articulares y sus repercusiones clínicas. Sujetos y métodos: Se realizó un estudio computarizado de la marcha sobre 30 sujetos adultos sanos (27,13 ± 3,82 a˜nos) con un índice de postura del pie (FPI) neutro (entre 0 y +5). Se estimaron los ángulos y momentos articulares externos en 3 dimensiones mediante un modelo que considera 3 segmentos (antepié, retropié y hallux) y se analizó la evolución de dichas variables durante la marcha sobre la articulación del mediopié (articulación que conecta antepié y retropié) del pie derecho de todos los sujetos. Resultados: Los mayores momentos articulares observados se dieron en el plano sagital en flexión dorsal produciendo una tendencia al colapso o aplanamiento del pie durante la fase de apoyo de la marcha. Los momentos articulares registrados en los planos frontal y transverso fueron de una magnitud mucho menor que la observada en el plano sagital y de menor relevancia clínica. Discusión: El presente estudio aporta datos sobre el comportamiento mecánico de las articulaciones del mediopié en una muestra de 30 sujetos sanos con un FPI neutro. Este estudio muestra la importancia del estrés tensional al que se encuentran sometidas las estructuras blandas plantares durante la fase de apoyo de la marcha.Introduction: There is not enough evidence in form of clinical studies regarding the behavior of the midfoot joints in dynamic situations such us walking or running. The present work aims to study the mechanical behavior of midfoot joints with a multisegmented foot model with special interest in joint moments and their clinical significance. Subjects and methods: A computerized 3-dimensional gait study was performed on 30 healthy male adult subjects (27.13 ± 3.82 years) with a neutral Foot Posture Index (FPI) (from 0 to +5) during walking. Joint angle and external moments were estimated with a multisegment foot model that considers three separate segments (forefoot, rearfoot and hallux) and graphs and values of midfoot joint (joint connecting forefoot to rearfoot) were analyzed for the right foot of all participants. Results: Highest external moments were observed in the sagittal plane in dorsiflexion direction which tend to collapse the longitudinal arch during the stance phase. Moments registered in frontal and transverse planes were much lower than those observed in the sagittal plane and seemed to have lower clinical relevance. Discussion: The present study provides data about the mechanical behavior of midfoot joints in a healthy adult population with a neutral FPI. This work shows that plantar soft tissues are subjected to important tensional stress during the stance phase of walking

3D characterisation of the dynamics of foot joints of adults during walking. Gait pattern identification

A detailed description of the kinematics and kinetics of the ankle, midtarsal and metatarsophalangeal joints of the feet of a healthy adult male population during barefoot walking is provided. Plots of the angles and moments in each plane during the stance phase are reported, along with the mean and standard deviation values of 87 different parameters that characterise the 3D dynamics of the foot joints. These parameters were used to check for similarities between subjects through a hierarchical analysis that allowed three different gait patterns to be identified, most of the differences corresponding to the frontal and transverse planes

Evaluating a Kinematic Data Glove with Pressure Sensors to Automatically Differentiate Free Motion from Product Manipulation

When studying hand kinematics, it is key to differentiate between free motion and manipulation. This differentiation can be achieved using pressure sensors or through visual analysis in the absence of sensors. Certain data gloves, such as the CyberGlove II, allow recording hand kinematics with good accuracy when properly calibrated. Other gloves, such as the Virtual Motion Glove 30 (VMG30), are also equipped with pressure sensors to detect object contact. The aim of this study is to perform a technical validation to evaluate the feasibility of using virtual reality gloves with pressure sensors such as the VMG30 for hand kinematics characterization during product manipulation, testing its accuracy for motion recording when compared with CyberGlove as well as its ability to differentiate between free motion and manipulation using its pressure sensors in comparison to visual analysis. Firstly, both data gloves were calibrated using a specific protocol developed by the research group. Then, the active ranges of motion of 16 hand joints angles were recorded in three participants using both gloves and compared using repeated measures ANOVAs. The detection capability of pressure sensors was compared to visual analysis in two participants while performing six tasks involving product manipulation. The results revealed that kinematic data recordings from the VMG30 were less accurate than those from the CyberGlove. Furthermore, the pressure sensors did not provide additional precision with respect to the visual analysis technique. In fact, several pressure sensors were rarely activated, and the distribution of pressure sensors within the glove was questioned. Current available gloves such as the VMG30 would require design improvements to fit the requirements for kinematics characterization during product manipulation. The pressure sensors should have higher sensitivity, the pressure sensor’s location should comprise the palm, glove fit should be improved, and its overall stiffness should be reduced

Sharing of hand kinematic synergies across subjects in daily living activities

The motor system is hypothesised to use kinematic synergies to simplify hand control. Recent studies suggest that there is a large set of synergies, sparse in degrees of freedom, shared across subjects, so that each subject performs each action with a sparse combination of synergies. Identifying how synergies are shared across subjects can help in prostheses design, in clinical decision-making or in rehabilitation. Subject-specific synergies of healthy subjects performing a wide number of representative daily living activities were obtained through principal component analysis. To make synergies comparable between subjects and tasks, the hand kinematics data were scaled using normative range of motion data. To obtain synergies sparse in degrees of freedom a rotation method that maximizes the sum of the variances of the squared loadings was applied. Resulting synergies were clustered and each cluster was characterized by a core synergy and different indexes (prevalence, relevance for function and within-cluster synergy similarity), substantiating the sparsity of synergies. The first two core synergies represent finger flexion and were present in all subjects. The remaining core synergies represent coordination of the thumb joints, thumb-index joints, palmar arching or fingers adduction, and were employed by subjects in different combinations, thus revealing different subject-specific strategies

Hand Kinematics Characterization While Performing Activities of Daily Living Through Kinematics Reduction

Improving the understanding of hand kinematics during the performance of activities of daily living may help improve the control of hand prostheses and hand function assessment. This work identifies sparse synergies (each degree of freedom is present mainly in only one synergy), representative of the global population, with emphasis in unveiling the coordination of joints with small range of motion (palmar arching and fingers abduction). The study is the most complete study described in the literature till now, involving 22 healthy subjects and 26 representative day-to-day life activities. Principal component analysis was used to reduce the original 16 angles recorded with an instrumented glove. Five synergies explained 75% of total variance: closeness (coordinated flexion and abduction of metacarpophalangeal finger joints), digit arching (flexion of proximal interphalangeal joints), palmar-thumb coordination (coordination of palmar arching and thumb carpometacarpal flexion), thumb opposition , and thumb arch . The temporal evolution of these synergies is provided during reaching per intended grasp and during manipulation per specific task, which could be used as normative patterns for the global population. Reaching has been observed to require the modulation of closeness , digit arch and thumb opposition synergies, with different control patterns per grasp. All the synergies are very important during manipulation and need to be modulated for all the tasks. Finally, groups of tasks with similar kinematic requirements in terms of synergies have been identified, which could benefit the selection of tasks for rehabilitation and hand function assessments

Identification of forearm skin zones with similar muscle activation patterns during activities of daily living

Background A deeper knowledge of the activity of the forearm muscles during activities of daily living (ADL) could help to better understand the role of those muscles and allow clinicians to treat motor dysfunctions more effectively and thus improve patients’ ability to perform activities of daily living. Methods In this work, we recorded sEMG activity from 30 spots distributed over the skin of the whole forearm of six subjects during the performance of 21 representative simulated ADL from the Sollerman Hand Function Test. Functional principal component analysis and hierarchical cluster analysis (HCA) were used to identify forearm spots with similar muscle activation patterns. Results The best classification of spots with similar activity in simulated ADL consisted in seven muscular-anatomically coherent groups: (1) wrist flexion and ulnar deviation; (2) wrist flexion and radial deviation; (3) digit flexion; (4) thumb extension and abduction/adduction; (5) finger extension; (6) wrist extension and ulnar deviation; and (7) wrist extension and radial deviation. Conclusion The number of sEMG sensors could be reduced from 30 to 7 without losing any relevant information, using them as representative spots of the muscular activity of the forearm in simulated ADL. This may help to assess muscle function in rehabilitation while also simplifying the complexity of prosthesis control

An eye-tracking study to assess the perception of usability affordances of assistive devices. An application to jar openers

Some assistive devices (ADs) aim to ease elders performing daily activities by changing postural and strength requirements. Elders usually have cognitive lacks too, making AD usability perception an important issue. Usability perceptions arise from the affordances conveyed by the AD: design features should act as signifiers transmitting opportunities of how to use the AD. This study assesses the perception of jar openers usability. Eye-tracking (ET) data from 56 subjects were used. Rendered images of 6 ADs were shown, in 2 versions: with and without rubber on the grip area. Each slide showed the 6 ADs, each AD image being an area of interest (AoI) to be tracked. The participants ranked the ADs in the next usability affordances: comfort, effort level, easiness to grip, easiness to use, lid slippery and robustness. For each affordance, they were eye-tracked while deciding the best AD, and afterwards they ranked the other ADs. The ranks were transformed into scores, and their correlation with ET parameters (decision time and number of fixations on each AoI) were studied, along with the effect of the rubber on the scores. Heat maps were also analyzed to identify the signifiers of the ADs that attract attention on usability. The results showed the potentiality of ET to study the perception of ADs usability affordances, and that the addition of rubber on the grip area of the jar openers or the material and shape of the lid area have an effect on their understanding and use

Effect on hand kinematics when using assistive devices during activities of daily living

Assistive devices (ADs) are products intended to overcome the difficulties produced by the reduction in mobility and grip strength entailed by ageing and different pathologies. Nevertheless, there is little information about the effect that the use of these devices produces on hand kinematics. Thus, the aim of this work is to quantify this effect through the comparison of kinematic parameters (mean posture, ROM, median velocity and peak velocity) while performing activities of daily living (ADL) using normal products and ADs. Twelve healthy right-handed subjects performed 11 ADL with normal products and with 17 ADs wearing an instrumented glove on their right hand, 16 joint angles being recorded. ADs significantly affected hand kinematics, although the joints affected differed according to the AD. Furthermore, some pattern effects were identified depending on the characteristics of the handle of the ADs, namely, handle thickening, addition of a handle to products that initially did not have one, extension of existing handles or addition of handles to apply higher torques. An overview of the effects of these design characteristics on hand kinematics is presented as a basis for the selection of the most suitable AD depending on the patient’s impairments

A calibrated database of kinematics and EMG of the forearm and hand during activities of daily living

Linking hand kinematics and forearm muscle activity is a challenging and crucial problem for several domains, such as prosthetics, 3D modelling or rehabilitation. To advance in this relationship between hand kinematics and muscle activity, synchronised and well-defined data are needed. However, currently available datasets are scarce, and the presented tasks and data are often limited. This paper presents the KIN-MUS UJI Dataset that contains 572 recordings with anatomical angles and forearm muscle activity of 22 subjects while performing 26 representative activities of daily living. This dataset is, to our knowledge, the biggest currently available hand kinematics and muscle activity dataset to focus on goal-oriented actions. Data were recorded using a CyberGlove instrumented glove and surface EMG electrodes, both properly synchronised. Eighteen hand anatomical angles were obtained from the glove sensors by a validated calibration procedure. Surface EMG activity was recorded from seven representative forearm areas. The statistics verified that data were not affected by the experimental procedures and were similar to the data acquired under real-life conditions