44 research outputs found

    Sliding-mode adaptive control of Pioneer 3-DX wheeled mobile robot

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    Parameter identification scheme and discrete-time adaptive sliding-mode controller applied to Pioneer 3-DX wheeled mobile robot (WMR) are presented in this paper. The dynamical model for mobile robot with one pair of active wheels, time–varying mass and moment of inertia have been used in sliding-mode control. Two closed-loop, on-line parameter estimators have been used in order to achieve robustness against parameter uncertainties (robot mass and moment of inertia). Two sliding-mode adaptive controllers corresponding to angular and position motion have been designed. Closed-loop circular trajectory tracking Pioneer 3-DX real-time control is presented

    Sliding Mode Control for Trajectory Tracking of an Intelligent Wheelchair

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    This paper deal with a robust sliding-mode trajectory tracking controller, fornonholonomic wheeled mobile robots and its experimental evaluation by theimplementation in an intelligent wheelchair (RobChair). The proposed control structureis based on two nonlinear sliding surfaces ensuring the tracking of the three outputvariables, with respect to the nonholonomic constraint. The performances of theproposed controller for the trajectory planning problem with comfort constraint areverified through the real time acceleration provided by an inertial measurement unit

    Applied 3D Virtual Try-on for Bodies with Atypical Characteristics

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    AbstractThe manufacture of clothing using real body measurements is based on user's new profile, on their own desire for individualization through purchased garments but also on the results of the anthropometric surveys which have shown great variability in morphological types, especially for women.Research conducted by the authors focused on the application of 3D virtual try-on in pattern alterations for “women trousers”. To achieve the objectives of the work, bodies with atypical characteristics were selected from the database resulting from 3D scanning of the Romanian women population. In the study, it was found that many women have different sizes for the two hip contours (left-right), differences being in the range 1.5 to 4.5cm.Based on these considerations a method of completion of the patterns for trousers has been developed and applied, by 3D simulation of the body-garment.This paper brings contributions to clothing design technology by 3D virtual try-on, taking into account the body shape of the users

    Computer Aided Model for a Low Voltage Varistor with Increased Thermal Stability

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    Metal Oxide Varistors are a very common power electronic device, applied for efficient overvoltage protection at any voltage level. This piece of equipment has a high non-linear current response function of the applied voltage, and, it provides a relatively high heat absorption capacity in case of accidental overvoltage pulse (shock)s. The crossing response current is clearly activated by temperature of that device, and, by consequent, overheating could be disastrous. Actual researches must be carried out both for a new more performant material as well as for new technical solutions for the design of all equipment integrating them, by studying heat extraction and heat transfer inside a new complex varistor device. Our article proposes a totally new device, used basically for low voltage applications, having a supplementary metal mass added to the body of that varistor, shaped as small disk. It actions like a heat pump immediately after the voltage pulse (shock) and as additional radiators at the end of the heating process caused by a transitory overvoltage. A CAD solution combined with a finite element model, followed by some experimental results are also presented, for confirming the performance of that newly design. By placing additional metal alloy masses inside a new varistor structure it will have a higher heat pumping and dissipation capability, in order to reduce temperature stress and all aging effects

    Nanostructured PbS-doped inorganic film synthesized by sol-gel route

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    IV-VI semiconductor quantum dots embedded into an inorganic matrix represent nanostructured composite materials with potential application in temperature sensor systems. This study explores the optical, structural, and morphological properties of a novel PbS quantum dots (QDs)- doped inorganic thin film belonging to the Al2O3 -SiO2 -P2O5 system. The film was synthesized by the sol-gel method, spin coating technique, starting from a precursor solution deposited on a glass substrate in a multilayer process, followed by drying of each deposited layer. Crystalline PbS QDs embedded in the inorganic vitreous host matrix formed a nanocomposite material. Specific investigations such as X-ray diffraction (XRD), optical absorbance in the ultraviolet (UV)-visible (Vis)-near infrared (NIR) domain, NIR luminescence, Raman spectroscopy, scanning electron microscopy– energy dispersive X-ray (SEM-EDX), and atomic force microscopy (AFM) were used to obtain a comprehensive characterization of the deposited film. The dimensions of the PbS nanocrystallite phase were corroborated by XRD, SEM-EDX, and AFM results. The luminescence band from 1400 nm follows the luminescence peak of the precursor solution and that of the dopant solution. The emission of the PbS-doped film in the NIR domain is a premise for potential application in temperature sensing systems.This study was funded by a grant of the Romanian National Authority for Scientific Research and Innovation, CCCDI–UEFISCDI, project ERANET-MANUNET-TEMSENSOPT, MNET20/ NMCS3732, within PNCDI III, contract 213/02.12.2020; Ministry of Research, Innovation and Digitalization (MRID), Core Program, contracts no. 16N/2019, 18N/2019 and 21N/2019; MRID through Program I—Development of the National R & D System, Subprogram 1.2–Institutional Performance– Projects for Excellence Financing in RDI, contracts no. 13PFE/2021, 18PFE/2021 and 35PFE/2021; CCCDI-UEFISCDI project PN-III-P2-2.1-PED-2021-2541. Support from the Public University of Navarre for Research Groups is also acknowledged

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Manufacturing Technology on a Mechatronics Line Assisted by Autonomous Robotic Systems, Robotic Manipulators and Visual Servoing Systems

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    This paper proposes the implementation of an assisting technology to a processing/reprocessing mechatronics line (P/RML), comprising the following: two autonomous robotic systems (ARSs), two robotic manipulators (RMs) and three visual servoing systems (VSSs). The P/RML has four line-shaped workstations assisted by two ARSs—wheeled mobile robots (WMRs): one of them equipped with an RM, used for manipulation, and the other one used for transport. Two types of VSSs—eye to hand and eye in hand—are used as actuators for precise positioning of RMs to catch and release the work-piece. The work-piece visits stations successively as it is moved along the line for processing. If the processed piece does not pass the quality test, it is taken from the last stations of the P/RML and it is transported to the first station where it will be considered for reprocessing. The P/RML, assisted by ARSs, RMs and VSSs, was modelled with the synchronized hybrid Petri nets (SHPN). To control the ARSs, we propose the use of trajectory-tracking and sliding-mode control (TTSMC). The precise positioning that allows the picking up and releasing of the work-piece was performed using two types of VSSs. In the case of the first one, termed eye to hand VSS, the cameras have a fixed position, located at the last and the first workstations of the P/RML. For the second one, named eye in hand VSS, the camera is located at the end effector of the RM
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