Digital twin control of multi-axis wood CNC machining center based on LinuxCNC

Abstrack: This paper presents an application of an open architecture control system implemented on a multi-axis wood computer numerical control milling machining center, as a digital twin control. The development of the digital twin control system was motivated by research and educational requirements, especially in the field of configuring a new control system by “virtual commissioning”, enabling the validation of the developed controls, program verification, and analysis of the machining process and monitoring. The considered wood computer numerical control (CNC) machining system is supported by an equivalent virtual machine in a computer-aided design and computer-aided manufacturing (CAD/CAM) environment, as well as in the control system, as a digital twin. The configured virtual machines are used for the verification of the machining program and programming system via machining simulation, which is extremely important in multi-axis machining. Several test wood workpieces were machined to validate the effectiveness of the developed control system based on LinuxCNC

Programming of 3-Axis Hybrid Kinematics CNC Machine for Rapid Prototyping Using Subtractive and Additive Processes

The paper presents the programming and program verification on a 3-axis hybrid kinematics CNC machine for rapid prototyping using subtractive and additive processes. The original hybrid (parallel-serial) 3-axis O-X glide mechanism developed to build a rapid prototyping machine and multifunctional machine tools is presented. The paper analyzes the available programming software, which can be one of the standard CAD/CAM systems or a specialized CAM system, for subtractive processes, i.e. desktop milling. For the additive processes, the software for generating G code based on the STL file as well as the possibility of simulating the machine when working is considered. To verify the program, the simulation of material removal for subtractive processes as well as the simulation of material addition for additive processes were considered. The paper presents the prototype of a hybrid kinematics CNC machine and some of the results of testing with an open control system based on the LinuxCNC

The comparative responsiveness of Hospital Universitario Princesa Index and other composite indices for assessing rheumatoid arthritis activity

Objective To evaluate the responsiveness in terms of correlation of the Hospital Universitario La Princesa Index (HUPI) comparatively to the traditional composite indices used to assess disease activity in rheumatoid arthritis (RA), and to compare the performance of HUPI-based response criteria with that of the EULAR response criteria. Methods Secondary data analysis from the following studies: ACT-RAY (clinical trial), PROAR (early RA cohort) and EMECAR (pre-biologic era long term RA cohort). Responsiveness was evaluated by: 1) comparing change from baseline (Delta) of HUPI with Delta in other scores by calculating correlation coefficients; 2) calculating standardised effect sizes. The accuracy of response by HUPI and by EULAR criteria was analyzed using linear regressions in which the dependent variable was change in global assessment by physician (Delta GDA-Phy). Results Delta HUPI correlation with change in all other indices ranged from 0.387 to 0.791); HUPI's standardized effect size was larger than those from the other indices in each database used. In ACT-RAY, depending on visit, between 65 and 80% of patients were equally classified by HUPI and EULAR response criteria. However, HUPI criteria were slightly more stringent, with higher percentage of patients classified as non-responder, especially at early visits. HUPI response criteria showed a slightly higher accuracy than EULAR response criteria when using Delta GDA-Phy as gold standard. Conclusion HUPI shows good responsiveness in terms of correlation in each studied scenario (clinical trial, early RA cohort, and established RA cohort). Response criteria by HUPI seem more stringent than EULAR''s

Ispitivanje tačnosti pozicioniranja mašina alatki sa hibridnom kinematikom prema standardu ISO 230-2

Mašine alatke sa parelelno-serijskom (hibridnom) kinematskom strukturom predstavljaju nekonvencionalan tip mašina alatki čije karakteristike zavise od kinematske konfiguracije. Zbog toga je neophodno da se za svaki tip mehanizma izvrši posebna analiza tačnosti. Ako tačnost neke mašine opisujemo kao karakteristiku koja je posledica niza osobina mehaničke i upravljačke strukture, onda je jedan od najboljih pokazatelja karakteristika mašine stanje tačnosti pozicioniranja. Kod konvencionalnih mašina alatki koje se baziraju isključivo na serijskoj (rednoj) kinematskoj strukturi postoje standardi i preporuke (ISO 230-2, VDI DGQ 3441), koje se bave problemom tačnosti pozicioniranja. U ovom radu se opisuje merenje tačnosti pozicinoranja mašine alatke sa hibridnom kinematskom strukturom „O-X glide“ prema standardu ISO 230-2 i analiziraju se dobijeni rezultati

Programming methodology for multi-axis CNC woodworking machining center for advanced manufacturing based on STEP-NC

The paper proposes a programming methodology for advanced manufacturing based on STEP-NC, a compliant to multi-axis CNC woodworking machining center. The equivalent virtual machine in the CAD/CAM, STEP-NC environment, is developed as a part of a programming system for considered CNC woodworking machining center. STEP-NC aims to provide a digital thread for CNC manufacturing running in the STEP-NC System world via the Internet that can enable advanced e-Manufacturing. Virtual machine as a digital twin is configured and implemented into the control system based on LinuxCNC, but configured virtual machine as a Web interface based on STEP-NC, also. The developed methodology is validated through machining simulation using the configured digital twin in the control system and machining experiments on the real machine

System Interface Design For CAD/CAM-Simulink Data Exchange System Using MATLAB

Integration between advanced control system theory and automation tools and technology brings about advancement in machining technology in tandem with requirement for smart and flexible manufacturing system. The integration takes in the form of seamless and automatic data communication between a CAD/CAM system and the more advanced control systems technology. This paper presents an interface design of a novel CAD/CAM-Simulink Data Exchange System (CS-DES) which links part geometry design using CAD/CAM technology with position controller scheme and algorithm designed in Matlab/Simulink environment. The proposed CS-DES system enhances data automation through formation of the graphical user input reference interface of the machine tools control system using NC manufacturing codes data as the reference input signal. The framework and role of CS-DES are elaborated and described in detail including pseudocodes generation for the CAD drawing graphical data integrated with the controller scheme designed in Simulink. The CS-DES interface was designed using MATLAB graphical user interactive development platform. Functions related to the user interface design are discussed in this paper. Finally, the system interface design of the data exchange system is expected to further enhance versatility of existing control system performance of a machine tool via creation of flexible input reference forms hence improving system accuracy, efficiency and productivity

Cold-Pressed Pumpkin Seed Oil Antioxidant Activity as Determined by a DC Polarographic Assay Based on Hydrogen Peroxide Scavenge

Antioxidant (AO) activity of cold pressed pumpkin (Cucurbita pepo L.) seed oil, produced from three naked and one hulled variety, was assessed using a DC polarographic assay based on a hydrogen peroxide scavenge (HPS). Results are expressed as the decrease of the anodic oxidation current of hydrogen peroxide obtained upon addition of methanolic extract of the investigated oils. Strict correlations of HPS and (1) radical scavenging capacity against the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) (0.99), (2) the induction period estimated by a Rancimat test (0.99) and (3) total phenolic content estimated by Folin-Ciocalteu (FC) assay (0.99) were obtained. In addition, a significant correlation of HPS and the content of delta-tocopherol (0.87), squalene (0.67) and color CIE a* (-0.89) was found. Based on the results reported, the polarographic assay was found to be suitable for determination of AO activity as an indicator of the quality and oxidative stability of oil

The Significance of COVID-19 Diseases in Lipid Metabolism Pregnancy Women and Newborns

Coronavirus disease (COVID-19) is an infectious disease caused by SARS-CoV-2. Elderly people, people with immunodeficiency, autoimmune and malignant diseases, as well as people with chronic diseases have a higher risk of developing more severe forms of the disease. Pregnant women and children can becomesick, although more often they are only the carriers of the virus. Recent studies have indicated that infants can also be infected by SARS-CoV-2 and develop a severe form of the disease with a fatal outcome. Acute Respiratory Distress Syndrome (ARDS) ina pregnant woman can affect the supply of oxygen to the fetus and initiate the mechanism of metabolic disorders of the fetus and newborn caused by asphyxia. The initial metabolic response of the newborn to the lack of oxygen in the tissues is the activation of anaerobic glycolysis in the tissues and an increase in the concentration of lactate and ketones. Lipid peroxidation, especially in nerve cells, is catalyzed by iron released from hemoglobin, transferrin and ferritin, whose release is induced by tissue acidosis and free oxygen radicals. Ferroptosis-inducing factors can directly or indirectly affect glutathione peroxidase through various pathways, resulting in a decrease in the antioxidant capacity and accumulation of lipid reactive oxygen species (ROS) in the cells, ultimately leading to oxidative cell stress, and finally, death. Conclusion: damage to the mitochondria as a result of lipid peroxidation caused by the COVID-19 disease can cause the death of a newborn and pregnant women as well as short time and long-time sequelae