New motion control machine elements representation for mechatronic education

The paper presents a new proposal for representing machine designs involving motion control. The new mechatronic approach for machine design is moving from a mechanic concept where mechanical transmissions, mechanical gears and coupling etc. are being implemented by electronic coupling, gears, etc. New concepts such as electronic virtual axis are also being employed very often. This brings that, in regards with machine design communication, mechanic elements represented in the past by mechanical drawings are being replaced by new electronic concepts. However, these new electronic motion control concepts should be also represented for a full understanding of the machine behaviors. Drawings are a fundamental tool to communicate preliminary designs, both in an academic and education environments as in professional ones. The new mechatronic elements graphical representation presented in the paper has the objective of bringing the gap between a pure mechanical machine design view and an automated one, including new electronic motion control concepts, and remarking the relevant “mechanic” information from the electronic motion control point of view. All this should facilitate the presentation and explanation of system-based mechatronic designs both in the classroom and at the professional level

STEP-NC-compliant implementation to support mixed-control technologies applied to stone-processing machines based on industrial automation standards

STEP-NC (Standard for the Exchange of Product Model Data–Numerical Control) for metal milling and turning is not implemented by industrial computer numerical controllers. Solutions reported are prototypes based on post-processing in G-code. Moreover, minority machining processes, such as stone cutting, have not yet been contemplated in the STEP-NC standard. This article takes that sector as a use case. An extended STEP-NC model for circular saw stone-cutting operations is proposed, and a prototype automation implementation is developed to work with this extended model. This article shows how modern technological resources for coordinated axes control provided by many industrial controllers for the automation of general-purpose machines can speed up the processes of implementing STEP-NC numerical controllers. This article proposes a mixed and flexible approach for STEP-NC-based machine automation, where different strategies can coexist when it comes to executing STEP-NC machining files, so controllers do not need to implement the standard in an exhaustive way for all the possible features, but only at selected ones when convenient. This is demonstrated in a prototype implementation which is able to process STEP-NC product files with mixed-feature types: standard milling and non-standard sawblade features for stone processing

On-board and port 3D printing to promote a maritime plastic circular economy

Oceanic plastic pollution has become one of the most serious problems in terms of the environment, and Circular Economy (CE) strategies are being implemented to reduce it. The article presents the results of a diagnosis of plastic waste in the maritime sector and the use of 3D printing as an enabling technology of CE around plastic. Maritime industries were asked about their plastic waste generation and potential parts and components which could be replaced by equivalent parts made by 3D printing. To close the CE loop, these parts would be printed with filament from the maritime industries’ plastic waste. The article addresses this process of generating filament that enables the CE and how this printing process can be affected and corrected under on-board conditions. A polypropylene-based strapping tape waste was chosen to produce recycled filament. This filament resulted stiffer than the commercial filament and, through an additivation process, it achieved better flexural properties. Finally, the 3D printing process during on-board unstable conditions was improved by an automatic and electronic correction on the 3D printer machine itself.European Regional Development Fund | Ref. EAPA_117/2018Universidade de Vigo/CISU

Automatic generation of digital twin industrial system from a high level specification

A framework for the generation of industrial digital twins is presented in the paper. The framework supports industry automated systems preliminary design development, but also supports the following detailed designs implementation and final systems exploitation phases. The main problem is that requirements for first development phases are much more generic than those required for the later phases. The framework faces this problem by avoiding too detailed specifications for the digital twin generated software, but, at the same time, it takes advantage of the specific applications developed for each industrial implementation where that specificities are taken into account: the final control application and the management application. By properly linking both: the more generic digital twin and specific software applications specifically generated for the industry system, the framework may be ready to be used soon at the early development stages, but also may be used for detailed analyses at late booting and maintenance industry system phases. The system has been specialized in industrial transportation and warehouse systems. The paper presents an example of application for this kind of system

Representación integrada de accionamientos mecánicos y control de ejes orientada a la comunicación y docencia en mecatrónica

[Resumen] La aproximación “mecatrónica” al diseño y realización de máquinas hace un uso extensivo de tecnologías electrónicas para el control y coordinación de ejes mecánicos permitiendo que el control realice funcionalidades que antes eran hechas únicamente por los elementos mecánicos. Sin embargo, los métodos existentes para representar estas dos vistas tecnológicas (mecánica y electrónica/lógica) se han ignorado mutuamente, paralelamente a lo que sucedía con los perfiles docentes y profesionales correspondientes: mecánico y automático. Esto, desde el punto de vista docente, complica por ejemplo la descripción pedagógica de sistemas mecánicos servoaccionados con todos los requerimientos propios de una solución mecatrónica conjunta. Este artículo desarrolla un nuevo modelo de representación de diseños mecatrónicos que integre efectivamente ambas vistas tecnológicas. El uso de esta metodología facilitará la comunicación entre diseñadores mecánicos y diseñadores de control, así como la introducción de restricciones mecánicas en docencia de control y viceversa

Detailed energy analysis of a sheet-metal-forming press from electrical measurements

This paper presents a methodology that allows for the detection of the state of a sheet-metal-forming press, the parts being produced, their cadence, and the energy demand for each unit produced. For this purpose, only electrical measurements are used. The proposed analysis is conducted at the level of the press subsystems: main motor, transfer module, cushion, and auxiliary systems, and is intended to count, classify, and monitor the production of pressed parts. The power data are collected every 20 ms and show cyclic behavior, which is the basis for the presented methodology. A neural network (NN) based on heuristic rules is developed to estimate the press states. Then, the production period is determined from the power data using a least squares method to obtain normalized harmonic coefficients. These are the basis for a second NN dedicated to identifying the parts in production. The global error in estimating the parts being produced is under 1%. The resulting information could be handy in determining relevant information regarding the press behavior, such as energy per part, which is necessary in order to evaluate the energy performance of the press under different production conditions.Xunta de Galicia | Ref. IN854A 2020/0

Eradication of bovine tuberculosis at a herd-level in Madrid, Spain: study of within-herd transmission dynamics over a 12 year period

BACKGROUND Eradication of bovine tuberculosis (bTB) through the application of test-and-cull programs is a declared goal of developed countries in which the disease is still endemic. Here, longitudinal data from more than 1,700 cattle herds tested during a 12 year-period in the eradication program in the region of Madrid, Spain, were analyzed to quantify the within-herd transmission coefficient (β) depending on the herd-type (beef/dairy/bullfighting). In addition, the probability to recover the officially bTB free (OTF) status in infected herds depending on the type of herd and the diagnostic strategy implemented was assessed using Cox proportional hazard models. RESULTS Overall, dairy herds showed higher β (median 4.7) than beef or bullfighting herds (2.3 and 2.2 respectively). Introduction of interferon-gamma (IFN-γ) as an ancillary test produced an apparent increase in the β coefficient regardless of production type, likely due to an increase in diagnostic sensitivity. Time to recover OTF status was also significantly lower in dairy herds, and length of bTB episodes was significantly reduced when the IFN-γ was implemented to manage the outbreak. CONCLUSIONS Our results suggest that bTB spreads more rapidly in dairy herds compared to other herd types, a likely cause being management and demographic-related factors. However, outbreaks in dairy herds can be controlled more rapidly than in typically extensive herd types. Finally, IFN-γ proved its usefulness to rapidly eradicate bTB at a herd-level

Molecular characterization of new FBXL4 mutations in patients with mtDNA depletion syndrome

Encephalomyopathic mitochondrial DNA (mtDNA) depletion syndrome 13 (MTDPS13) is a rare genetic disorder caused by defects in F-box leucine-rich repeat protein 4 (FBXL4). Although FBXL4 is essential for the bioenergetic homeostasis of the cell, the precise role of the protein remains unknown. In this study, we report two cases of unrelated patients presenting in the neonatal period with hyperlactacidemia and generalized hypotonia. Severe mtDNA depletion was detected in muscle biopsy in both patients. Genetic analysis showed one patient as having in compound heterozygosis a splice site variant c.858+5G>C and a missense variant c.1510T>C (p.Cys504Arg) in FBXL4. The second patient harbored a frameshift novel variant c.851delC (p.Pro284LeufsTer7) in homozygosis. To validate the pathogenicity of these variants, molecular and biochemical analyses were performed using skin-derived fibroblasts. We observed that the mtDNA depletion was less severe in fibroblasts than in muscle. Interestingly, the cells harboring a nonsense variant in homozygosis showed normal mtDNA copy number. Both patient fibroblasts, however, demonstrated reduced mitochondrial transcript quantity leading to diminished steady state levels of respiratory complex subunits, decreased respiratory complex IV (CIV) activity, and finally, low mitochondrial ATP levels. Both patients also revealed citrate synthase deficiency. Genetic complementation assays established that the deficient phenotype was rescued by the canonical version of FBXL4, confirming the pathological nature of the variants. Further analysis of fibroblasts allowed to establish that increased mitochondrial mass, mitochondrial fragmentation, and augmented autophagy are associated with FBXL4 deficiency in cells, but are probably secondary to a primary metabolic defect affecting oxidative phosphorylation