Object Assembly Research Articles

Control and Transport of Passive Particles Using Self-Organized Spinning Micro-Disks

Traditional robotic systems have proven to be instrumental in object manipulation tasks for automated manufacturing processes. Object manipulation in such cases typically involves transport, pick-and-place and assembly of objects using automated conveyors and robotic arms. However, the forces at microscopic scales (e.g., surface tension, Van der Waals, electrostatic) can be qualitatively and quantitatively different from those at macroscopic scales. These forces render the release of objects difficult, and hence, traditional systems cannot be directly transferred to small scales (below a few millimeters). Consequently, novel micro-robotic manipulation systems have to be designed to take into account these scaling effects. Such systems could be beneficial for micro-fabrication processes and for biological studies. Here, we show autonomous position control of passive particles floating at the air-water interface using a collective of self-organized spinning micro-disks with a diameter of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${300}\,{\mathrm {\mu m}}$</tex-math></inline-formula> . First, we show that the spinning micro-disks collectives generate azimuthal flows that cause passive particles to orbit around them. We then develop a closed-loop controller to demonstrate autonomous position control of passive particles without physical contact. Finally, we showcase the capability of our system to split from an expanded to several circular collectives while holding the particle at a fixed target. Our system’s contact-free object manipulation capability could be used for transporting delicate biological objects and for guiding self-assembly of passive objects for micro-fabrication.

Assembly Sequence Planning with Deformable Linear Objects in the Smart Factory: Dilemmas and Injections

Smart factory consists of extensive automation (e.g., robotic actors) and minor human interventions. Additional characteristics are manufacturing a variety of products rapidly and accurately. Many of the products contain rigid objects assembled with deformable ones, especially deformable linear objects (DLO) such as wires. Deformable object behavior results in modifications of objects' shape and position thus influencing assembly processes. Assembly sequence planning (ASP) is an intractable issue in production management. ASP in a robotized environment such as the smart factory with objects deformations is even more challenging. Deformable objects assembly by robotic actors increase uncertainty and influence factory performances. The theory of constraints (TOC) suggests tools for improving factory performances by concentrating on production flow. The literature is lacking TOC-based tools investigating smart factories and Industry 4.0 aspects. One of TOC thinking process tools is a conflict resolution diagram. This diagram describes a dilemma influencing achieving desired goal and aids in identifying potential solutions (called "injections"). This paper describes ASP dilemma in smart factories regarding robotic manipulation with deformable objects. The dilemma between generic, unified automatic assembly on one hand and customized, designated assembly, on the other hand, is elaborated. An entity called "interaction" is introduced as an injection to the smart factory ASP dilemma. Interactions are defined based on physical, geometric, and manufacturing attributes. Defining interactions categories is an important step toward comprehensive automation of assemblies containing deformable objects. By so interactions are promising direction from both research and industrial perspectives for robotic ASP with deformable objects in smart factories.

Flexible robotic strategy for the assembly of ring-shaped elastic objects

This paper addresses the challenge of the robotized insertion of ring-shaped elastic objects into parts’ outer grooves, which is a key operation in several industrial processes. We propose a novel flexible strategy to insert ring-shaped elastic objects of different sizes and stiffnesses, exploiting a generic robot and a simple - yet effective - fixture. Despite the overall complexity of the procedure is entirely poured on the mentioned fixture, its simplicity of realization and implementation allows to equip the robot with a generic gripper, without the use of any additional sensor. The effectiveness of the proposed strategy is assessed via experimental tests, proving the efficiency and flexibility in the insertion of different ring-shaped elastic objects.

Mesoscale simulation approach for assembly of small deformable objects.

We adapt Vertex models to understand the physical origin of the formation of long-range ordered structures in repulsive soft particles. The model incorporates contributions from the volume and surface area of each particle. Sampling using Monte Carlo simulations allows the system to naturally select preferred structures. We observe transitions between a body-centered cubic ordered state and a disordered state. Constraints to the simulation domain can suppress or allow the system to follow a path similar to Martensitic transformations from one ordered state to another ordered state. Finally, we show that rapid quenches from a disordered state into the ordered region lead to metastable local particle arrangements instead of a large-scale single crystal.

Spline-based Path Planning and Reconfiguration for Rigid Multi-Robot Formations

This paper presents an approach for continuous path planning in rigid formations containing nonholonomic mobile robots using Beziér-splines. Unlike most existing approaches, the focus is on maintaining a rigid formation, as required in many scenarios such as object transport, handling or assembly. In these scenarios, a constant distance between the individual robots must be kept to avoid damaging the transported object. Also, limitations regarding the velocity and acceleration of each robot have to be taken into account, as every robot traverses in a slightly different path. Especially the distance from the center of the formation to an individual robot has a big impact on the path a mobile robot has to move on to comply with the formation constraints during an orientation change of the formation. Therefore, we use splines to control and optimize the curvature of the formation’s path and limit the velocity and acceleration. The usage of splines requires the calculation of specific support points that can be interpolated. To achieve this, we calculate the formation’s diameter, including the transported object and adjust the inflation radius of the global costmap. To guarantee a collision-free movement from the start to the target position, we use an existing path planner to generate an initial path. The employed Relaxed-A*-Algorithm provides fast computation and an almost optimal initial path, although this path is not continuous. From this path, we extract a number of support points based on the size of the formation. We then fit a fifth-degree Beziér-spline through these points to smooth the discontinuous path. The final result is a computationally efficient, smooth and jerk-limited path that induces minimal disturbances to the formation control. Also, this approach allows us to continuously transition from one formation to another, which can be used to pass narrow passages. To valid the path planning approach presented in this study we showcase simulative and experimental results.

The Effects of Diverse Exercise on Cognition and Mental Health of Children Aged 5-6 Years: A Controlled Trial.

The rate of learning and cognitive development is at its highest level in preschool-aged children, making this stage a critical period. Exercise has received increasing attention for its beneficial physical and mental health effects on the development of preschool children. This study investigated the effects of diverse exercise on the cognition of preschool children. Two classes were randomly selected from kindergarten classes of children aged 5–6 years, and designated as the experimental and control classes. Each class contained 20 children (10 boys and 10 girls) according to the kindergarten class system. The experimental class completed exercises according to the designed curriculum, while control class carried out exercises according to the regular teaching plan, for a study period of 12 weeks. The Wechsler Preschool and Primary Scale of Intelligence (WPPSI) and the Mental Health Questionnaire for Children were used to assess outcomes, both at the beginning and end of study. After 12 weeks, the experimental class has improved in the “Object Assembly,” “Block Design,” “Picture Completion,” and “Coding” (14.70 ± 2.14, p < 0.01; 14.54 ± 1.56, p < 0.01; 9.62 ± 2.06, p < 0.05; 15.92 ± 2.72, p < 0.05) in performance test, and showed improvements in the “Movement,” “Cognitive Ability,” “Sociality” and “Living Habits” (5.65 ± 0.59, p < 0.01; 11.20 ± 1.91, p < 0.05; 9.05 ± 1.72, p < 0.05; 7.10 ± 1.45, p < 0.05) in mental health outcomes. Diverse exercise has a significantly beneficial role in promoting the cognitive development of children aged 5–6 years, as well as a beneficial, albeit insignificant, role in their mental health.

Divalent Multilinking Bonds Control Growth and Morphology of Nanopolymers.

Assembly of nanoscale objects into linear architectures resembling molecular polymers is a basic organization resulting from divalent interactions. Such linear architectures occur for particles with two binding patches on opposite sides, known as Janus particles. However, unlike molecular systems where valence bonds can be envisioned as pointlike interactions nanoscale patches are often realized through multiple molecular linkages. The relationship between the characteristics of these linkages, the resulting interpatch connectivity, and assembly morphology is not well-explored. Here, we investigate assembly behavior of model divalent nanomonomers, DNA nanocuboid with tailorable multilinking bonds. Our study reveals that the characteristics of individual molecular linkages and their collective properties have a profound effect on nanomonomer reactivity and resulting morphologies. Beyond linear nanopolymers, a common signature of divalent nanomonomers, we observe an effective valence increase as linkages lengthened, leading to the nanopolymer bundling. The experimental findings are rationalized by molecular dynamics simulations.

Spins of primordial black holes formed in different cosmological scenarios

Primordial black holes (PBHs) could account for all or part of dark matter, as well as for some LIGO events. We discuss the spins of primordial black holes produced in different cosmological scenarios, with the emphasis on recently discovered possibilities. PBHs produced as a horizon-size collapse of density perturbations are known to have very small spins. In contrast, PBHs resulting from assembly of matterlike objects (particles, Q-balls, oscillons, etc.) can have large or small spins depending on their formation history and the efficiency of radiative cooling. We show that scalar radiation can remove the angular momentum very efficiently, leading to slowly rotating PBHs in those scenarios for which the radiative cooling is important. Gravitational waves astronomy offers an opportunity to determine the spins of black holes, opening a new window on the early Universe if, indeed, some black holes have primordial origin.

Exploratory Factor Analysis of the WAIS-III Thai Version in Patients with Mild Cognitive Impairment

Objective: To investigate the generalizability of the Wechsler Adult Intelligence Scale-III (WAIS-III) factors structure in a sample of mild cognitive impairment (MCI) patients. Materials and Methods: A retrospective study of patients older than 60 years receiving treatments at the Memory Clinic in Ramathibodi Hospital between January 2015 and July 2018 was conducted. The WAIS-III Thai version was used to measure the performance. All subtests except the Vocabulary and Object Assembly subtests were included for analyses. These 12 subtests were subjected to a principal axis factor analysis with oblique rotation and four factors were specified to be retained. Results: Out of 145 patients, 51% were female and 49%were male. The Full-Scale IQ ranged from 80 to 123 with the mean of 93.88 (SD 9.12). The mean of each subtest ranged from 7.82 (Similarities) to 10.45 (Digit Span), with the standard deviations ranging from 1.80 to 2.86. Based on the order of extraction and minimum loading criterion, results supported a four-factor solution composed of Verbal Comprehension, Perceptual Organization, Working Memory, and Processing Speed. The coefficients of congruence across groups on the four factors ranged from 0.92 for Perceptual Organization to 0.73 for Processing Speed. However, the Picture Completion subtest was found to have similar loadings between Perceptual Organization and Processing Speed, with the primary loading being on Perceptual Organization and secondary loading on Processing Speed. On the Working Memory factor, the MCI group showed areas of relatively greater divergence for Picture Arrangement, Block Design, and Digit Symbol: Coding subtests. Conclusion: Four factors from WAIS-III could be applied to patients with MCI. The decline of cognitive functions, particular in working memory, might be the explanation for the difference in loading factor among some subtests. Therefore, it might be possible to apply other models with other factors to the same patient group in the future. Keywords: Mild cognitive impairments; Exploratory factor analysis; WAIS-III

ADGRL3, FGF1 and DRD4: Linkage and Association with Working Memory and Perceptual Organization Candidate Endophenotypes in ADHD.

Attention deficit hyperactivity disorder (ADHD) is a highly heritable neurobehavioral disorder that affects children worldwide, with detrimental long-term consequences in affected individuals. ADHD-affected patients display visual–motor and visuospatial abilities and skills that depart from those exhibited by non-affected individuals and struggle with perceptual organization, which might partially explain impulsive responses. Endophenotypes (quantifiable or dimensional constructs that are closely related to the root cause of the disease) might provide a more powerful and objective framework for dissecting the underlying neurobiology of ADHD than that of categories offered by the syndromic classification. In here, we explore the potential presence of the linkage and association of single-nucleotide polymorphisms (SNPs), harbored in genes implicated in the etiology of ADHD (ADGRL3, DRD4, and FGF1), with cognitive endophenotypes related to working memory and perceptual organization in 113 nuclear families. These families were ascertained from a geographical area of the Caribbean coast, in the north of Colombia, where the community is characterized by its ethnic diversity and differential gene pool. We found a significant association and linkage of markers ADGRL3-rs1565902, DRD4-rs916457 and FGF1-rs2282794 to neuropsychological tasks outlining working memory and perceptual organization such as performance in the digits forward and backward, arithmetic, similarities, the completion of figures and the assembly of objects. Our results provide strong support to understand ADHD as a combination of working memory and perceptual organization deficits and highlight the importance of the genetic background shaping the neurobiology, clinical complexity, and physiopathology of ADHD. Further, this study supplements new information regarding an ethnically diverse community with a vast African American contribution, where ADHD studies are scarce.

The Power of Assembly

The Power of Assembly

Ion Transfer at Liquid | Liquid Interface Modified with Silica Nanoparticles

The interface formed between two immiscible electrolyte solutions (ITIES) is a highly reproducible, defect-free surface that allows the assembly of nanometer-sized objects. Their adsorption at the liquid-liquid interface is governed by their dimensions, zeta potential, wettability and the interfacial tension. The interest for the use of silica nanomaterials at the ITIES is due to their favourable adsorption kinetics and to their rich surface chemistry that can provide selectivity.At first, we followed the adsorption of silica nanoparticles (ø = 12 nm) at the ITIES by AC voltammetry and their interactions with methylene blue (MB+), selected as a model ion by cyclic voltammetry and UV-vis absorption spectroscopy. We determined the adsorption constant of the MB+ onto silica nanoparticles to be 1.66 × 105, which indicated a strong affinity between them. This is in contrast with two other ions tested (Eosin B and tetraethylammonium), which demonstrated low affinity for the silica nanoparticles.In a second step, we synthesized silica nanoparticles with diclofenac molecular imprint with the aim of selective accumulation of diclofenac, a commonly used nonsteroidal anti-inflammatory drug. The presence of imprint cavities greatly improved the affinity for diclofenac for the silica nanoparticles, in contrast with diclofenac analogue such as aceclofenac. Electrochemistry experiments (including cyclic and AC voltammetries) revealed that diclofenac transfer is blocked by the presence of molecularly imprinted nanoparticles at the ITIES.These two experimental examples show that target molecules can be accumulated at the ITIES by combining the ability of silica nanoparticles to adsorb onto the ITIES and their affinity for the targeted molecules. Such an accumulation localized at the interface could be of interest in sensing applications. Figure 1

Predicting Neurocognitive Change after Bilateral Deep Brain Stimulation of Subthalamic Nucleus for Parkinson's Disease

Deep brain stimulation (DBS) of the bilateral subthalamic nucleus (STN) is a standard surgical treatment option in patients with advanced Parkinson's disease. Adverse effects on cognitive function have been reported, impacting the quality of life of patients and caregivers. We aimed to investigate a quantitative predictive preexisting cognitive factor for predicting postoperative cognitive changes. Thirty-five patients underwent STN-DBS. A battery of neuropsychological tests were used to examine executive function, processing speed, and visuospatial function both preoperatively and 1 year postoperatively. A multiple logistic regression analysis was performed to investigate the relationships between preoperative factors and cognitive outcomes. The predictive value of the preoperative factors for global cognitive decline during long-term follow-up were evaluated. The patients exhibited significant changes in processing speed and visuospatial function after surgery. Using reliable change index values, lower preoperative scores on the Similarities and Object Assembly subtests of the Wechsler Adult Intelligence Scale III were associated with decreases in visuospatial function at 1 year after DBS. The odds ratios were 10.2 for Similarities and 9.53 for Object Assembly. The proportion of Mini Mental State Examination-maintained patients with low scores on the Similarities subtest was significantly lower than that of patients with high scores at 3 and 5 years. No factors were found to be related to decreases in processing speed. Preoperative evaluation of the Similarities and Object Assembly subtests may be useful to identify patients who are at a greater risk of experiencing decreases in visuospatial functioning after STN-DBS. Furthermore, a low score on the Similarities subtest may predict future global cognitive deterioration.

Retracted] Research on Automobile Assembly Line Optimization Based on Industrial Engineering Technology and Machine Learning Algorithm

Aiming at the lack of search depth of traditional genetic algorithm in automobile assembly line balance optimization, an improved genetic algorithm based on bagging integrated clustering is proposed for balance optimization. Through the integrated learning of several K‐means algorithm based learners through bagging, a population clustering analysis method based on bagging integrated clustering algorithm is established, and then, a dual objective automobile assembly line balance optimization model is established. The population clustering analysis method is used to improve the intersection link of genetic algorithm to improve the search depth. The effectiveness and search performance of the improved genetic algorithm in solving the double objective assembly line balance problem are verified in an example.

Twist modelling for assembly of wiring harnesses

Wiring harnesses and flexible objects assembly is a major issue for agile manufacturing. However, model-based prediction of shape is a rather complex task, rendering the pre-programming of robots a difficult procedure. The current model, extending previous works on modelling wiring harness mechanical behaviour, deals with twist mechanics. Twist is addressed through adding extra terms to the equations of a previously tested model regarding continuous mechanics. Results on the prediction of the shape are presented and the accuracy of the model is validated using the comparison against experimental data filtered with an image processing algorithm. The integration of the model into a simulation environment is also discussed.

ECONDARY INFORMATION PROCESSING METHODS WHILE ESTIMATING THE SPATIAL ORIENTATION OF OBJECTS

The study is devoted to solving the scientific problem of ensuring unbiasedness and increasing the efficiency of assessing the spatial orientation of objects by applying new methods of secondary information processing in software and hardware components of computer systems. The paper describes a developed method for compensating for magnetic anomalies that affect magnetically sensi-tive sensors of the inclinometer rotation angles. It is based on recording the inclinometer readings and the angle of rotation of the drill pipe as it rotates in the mouth of well in a range of 360 degrees. This makes it possible to determine and further take into account the value of the magnetic deviation from the drill string in the readings of the inclinometer. A method is described for determining the parameters of a magnetic anomaly from an external stationary source of a constant magnetic field by using redundant information from the readings of inclinometery transducers in the mouth of well and at the point of assessment. This allows to expand the bound-aries and scope of magnetometric transducers in difficult conditions. Methods for calculating the desired azimuth, as well as the pa-rameters of the intensity vector of the magnetic anomaly are proposed. The errors of inclinometers based on sensor devices of various physical nature (fluxgates, gyroscopes, accelerometers), both rigidly fixed and with the use of gimbals pendulum suspensions, are considered. The factors influencing the bias of the estimation of the angles of the spatial orientation of the drilling tool, expressed through the Euler angles, are analyzed. The analysis took into account the effect of various reasons: deviations of the transducers' sensitivity axes from mutual orthogonality and the reference trihedron of the axes associated with the body; changes in the zero sig-nal and transfer ratios under the influence of temperature; non-identical electrical parameters; inaccurate installation of the pendulum gimbal sensor frames in the tilt plane and along the vertical of the place. The permissible boundary values of each of the given errors have been determined. Consideration of these errors can significantly increase the unbiasedness of the assessment of the position of the object in difficult conditions. The practical significance of the results presented in the paper is the development of software and hardware components for assessing the spatial orientation of objects on the basis of the designed inclinometers capable of operating in difficult operating conditions and having a small diameter of the protective casing. Similar software and hardware components for assessing the spatial orientation of objects can be used: for the construction of underground communications; for the assembly of large-sized and remote objects; for static sounding of soils; for monitoring the state of building structure elements during operation.

Optocapillarity-driven assembly and reconfiguration of liquid crystal polymer actuators

Realizing programmable assembly and reconfiguration of small objects holds promise for technologically-significant applications in such fields as micromechanical systems, biomedical devices, and metamaterials. Although capillary forces have been successfully explored to assemble objects with specific shapes into ordered structures on the liquid surface, reconfiguring these assembled structures on demand remains a challenge. Here we report a strategy, bioinspired by Anurida maritima, to actively reconfigure assembled structures with well-defined selectivity, directionality, robustness, and restorability. This approach, taking advantage of optocapillarity induced by photodeformation of floating liquid crystal polymer actuators, not only achieves programmable and reconfigurable two-dimensional assembly, but also uniquely enables the formation of three-dimensional structures with tunable architectures and topologies across multiple fluid interfaces. This work demonstrates a versatile approach to tailor capillary interaction by optics, as well as a straightforward bottom-up fabrication platform for a wide range of applications.

Effects of Emotional Valence and Arousal on Comprehension and Assembly of Instructions

Research on multimedia comprehension from the emotional design perspective has suggested that including graphical elements enhances positive affect and learning. On the other hand, the seductive detail literature found that attractive but irrelevant images can hinder comprehension and learning. The present study has addressed the effect of decorative images with affective properties (valence and arousal) in procedural multimedia comprehension. First, a validation study determined the images’ affective properties; stimuli high or low in both dimensions were systematically introduced in the second experiment, which tested the images’ effect in mean study time when learning the instructions, and accuracy during object assembly. Low arousal images made participants study the instructions faster, and high arousal images led to more errors in performance. Valence did not have a differential effect. Overall, in line with the seductive detail effect, these findings argue against including irrelevant, highly arousing, emotional information in instructional materials.

El 'monstruo de las toallitas': relacionalidad material en el Antropoceno

En los últimos años se viene argumentando desde las ciencias sociales que es necesario prestar mas atención a los objetos, porque no solo los humanos actúan, también lo hacen los materiales. Tomando el ejemplo de la toallita húmeda exploraré cómo pueden actuar los materiales y qué relaciones son relevantes. Para ello movilizaré dos casos, el de la doekje, la toallita húmeda en Holanda, y el de “el monstruo de las toallitas” (la obstrucción del colector norte de Valencia por un atasco formado por una bola de toallitas, grasa y otros residuos). El caso de la toallita húmeda visibiliza que los objetos nunca actúan solos, siempre van a acompañados de prácticas (en este caso prácticas que tienen que ver con la higiene, la caca, y la infraestructura y gestión de los residuos fecales). No es que los objetos tengan agencia sobre los humanos, sino que los ensamblajes de toallitas y otros residuos pertenecen a prácticas concretas (en este caso qué hacemos con nuestra caca) recordándonos que en el contexto de crisis medioambiental es urgente pensar sobre los efectos materiales y semióticos de los objetos. La lección sería aprender a vivir con la abundancia material del Antropoceno de una mejor manera, más que defender que los objetos tengan agencia.

Correlates of intelligence via resting-state functional connectivity of the amygdala in healthy adults

Intelligence is a form of advanced cognition that includes reasoning, problem solving, pattern recognition, and establishing relationships among items. The amygdala plays an important role in cognitive processing, but the relationship between amygdalar function and intelligence has rarely been explored directly. Here, we investigated the relationship between resting-state functional connectivity (RSFC) of the amygdala and intelligence test performance in a large sample of healthy adults (N = 197). We found that two pairs of RSFCs were significantly increased in the high IQ group compared with that of the general IQ group. One of these RSFCs consisted of the right amygdala and the right superior parietal lobule, whereas the other RSFC consisted of the right amygdala and the left middle cingulum. In addition, we found that the brain regions in which the strength of RSFC significantly correlated with full IQ (FIQ) were mainly distributed in the parietal and limbic lobes. What’s more, a further mediation analysis indicated that the functional connectivity of the right amygdala and the right superior parietal lobule significantly mediated the correlation between comprehension and object assembly, whereas the functional connectivity of the right amygdala and the left middle cingulum mediated the association between similarities and digit symbol. These findings suggest that amygdalar RSFC may reflect individual differences in intelligence and mediate specific relationships among different intellectual abilities.