Ukupno harmoničko izobličenje i brzina prostorne modalne informacije za analizu haptičkog paralelnog gibanja

In this paper, two kinds of evaluation index for the haptic motion analysis in parallel multiple degrees–of–freedom (MDOF) system are proposed. At first, the spatial modal decomposition method based on discrete Fourier series expansion (DFS) is presented. Spatial modal information expresses a motion element that corresponds to a specific physical action. The spatial modal information can mathematically be defined by the Fourier coefficients. Then, this paper proposes the total harmonic distortion (THD) and the content rate of the haptic modal information as motion evaluation indexes. THD of the spatial modal information can evaluate the complexity of the human motion and/or the deformability of the contact environment. Content rate of the spatial modal information can evaluate the priority of motion element. Some experimental results on the bilateral motion control of a parallel five DOF haptic system are shown, in order to confirm the utility of the proposed indexes.U ovom radu predložena su dva indikatora vrednovanja haptičkog gibanja u paralelnom sustavu s više stupnjeva slobode. Prikazana je metoda prostorne modalne dekompozicije zasnovana na proširenom diskretnom Fourierovom redu. Prostorna modalna informacija predstavlja element koji odgovara specifičnoj fizikalnoj radnji. Prostorna modalna informacija matematički se može opisati koristeći Fourierove koeficijente. U ovom se radu kao indikatori za evaluaciju gibanja predlažu ukupno harmoničko izobličenje i brzina haptičke modalne informacije. Ukupnim harmoničkim izobličenjem prostorne modalne informacije može se ocijeniti kompleksnost ljudskog gibanja i/ili deformabilnost kontaktne okoline. Przina prostorne modalne informacije ocjenjuje prioritet elementa u gibanju. Kako bi se potvrdila korisnost predloženih indikatora vrednovanja prikazani su eksperimentalni rezultati dobiveni dvoosnim prostornim upravljanjem paralelnim haptičkim sustavom s pet stupnjeva slobode

Analiza FPGA implementacije bilateralnih algoritama upravljanja za dodirnu teleoperaciju

This paper presents the FPGA implementation of sliding mode control algorithm for bilateral teleoperation, such that, the problem of haptic teleoperation is addressed. The presented study improves haptic fidelity by widening the control bandwidth. For wide control bandwidth, short control periods as well as short sampling periods are required that was achieved by the FPGA. The presented FPGA design methodology applies basic optimization methods in order to meet the required control period as well as the required hardware resource consumption. The circuit specification was performed by the high-level programing language LabVIEW using the fixed-point data type. Hence, short design times for producing the FPGA logic circuit can be achieved. The proposed FPGA-based bilateral teleoperation was validated by master-slave experimental device.Ovaj rad opisuje FPGA implementaciju algoritama upravljanja kliznim režimima za bilateralnu teleoperaciju, pri čemu je opisan problem haptičke teleoperacije. Prikazano istraživanje poboljšava dodirnu pouzdanost proširenjem upravljačkog propusnog pojasa. Za široki propusni pojas, potrebni su kratki upravljački periodi i brzo vrijeme uzorkovanja, što je postignuto primjenom FPGA sklopovlja. Prikazana metodologija za projektiranje FPGA sklopovlja koristi osnovne optimizacijske metode s ciljem postizanja potrebnih upravljačkih perioda i zahtijevane fizičke iskorištenosti sklopovlja. Specifikacije sklopovlja su provedene programskim jezikom visoke razine LabVIEW uz korištenje podataka s nepomičnim decimalnim zarezom. Stoga je moguće implementirati traženu logiku na FPGA sklopovlje u kratkom vremenu. Opisana bilateralna teleoperacija temeljena na FPGA slopovlju je testirana na eksperimentalnom postavu s nadre.enim i podre.enim čvorom

From domestic to regional: The civil war conundrum and the cases of Syria and Algeria

This paper seeks to answer a simple question: When do regional powers get involved in civil wars? Some civil wars see a significant involvement of regional actors, while others show a remarkable level of isolation. What explains this difference? This research answers this question by looking at two case studies: the Algerian civil war (1991–2002) and the Syrian civil war (2011–up to date). The paper identifies and develops five factors of regional involvement. These are: capabilities, regional dynamics, country’s relevance, regional security issues/containment and domestic–external links. civil wars are today one of the most prominent and deadly forms of conflict, and this paper contributes to understanding the important but understudied issue of regional involvement.N/

Smith Predictor-Based Control with Distance Feedback for Haptic Systems Under Distributed Time-Delays

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Some remarks on Smith predictor-based control with distance feedback for a 3-DOF haptic system with distributed delays

International audienceThis paper focuses on the construction of a Smith predictor for network-based haptic systems. Roughly speaking, the idea is to use a predictor just on the haptic side in order to compensate the viscosity effect and to provide an accurate feeling in the case of contacts. A new approach is presented by using the available information on the distance from the virtual reality simulator and introducing it in the predictor in order to maintain the similarity between the "real" and the "predicted model". In order to validate the approach, experimental results are presented for constant and random varying delays (normal distributed and gamma with gap distributed), for a simple virtual environment and for a virtual box

Impacts of social restrictions on mental health and health behaviours of individuals with multimorbidity during Covid-19 pandemic

International audienceBackground Social restrictions and their possible impact on lifestyle make people with multimorbidity (≥2 co-existing chronic conditions) more vulnerable to poor perceived mental health and health behaviours modifications during the COVID-19 pandemic. Objective To understand the mental health status and health behaviour modifications among individuals with multimorbidity during different levels of COVID-19 social restrictions. Methods Longitudinal multinational cohort study consisting of two online questionnaires with its first wave taken place while social restrictions were imposed (May 2020), and its second wave with less social restrictions in place (November 2020). Including 559 participants (wave 1) and 147 participants from wave 1 (wave 2) with an average age of 34.30±12.35 and 36.21±13.07 years old. Mostly females living in Canada, France, India and Lebanon. Results The prevalence of multimorbidity was 27.68% (wave 1) and 35.37% (wave 2). While social restrictions were imposed, people with multimorbidity were 2 to 3 times more likely to experience psychological distress, depressive symptoms, increased stress or isolation than those without multimorbidity. Health behaviours were also modified during this period with people with multimorbidity being more likely to reduce their physical activity and increased their fruit and vegetable consumption. In wave 2, regardless of multimorbidity status, sexual desire continuously decreased while stress and psychological distress increased. Conclusion Mental health and health behaviours modifications occurred while social restrictions were imposed and people with multimorbidity were more severely impacted than those without multimorbidity, indicating a need for a more adapted approach of care during socially restrictive periods for this population

Trends in the Control Schemes for Bilateral Teleoperation with Time Delay

In the last two decades, an increasing interest has been observed in the development of effective bilateral teleoperation systems. One of the biggest challenges encountered however is the presence of time delay, which can cause instability and poor transparency to the system. Researchers have been trying to tackle this problem from different angles and various control schemes have been proposed and tested. This paper aims to do an overview of those schemes and to compare them based on their assessment in order to give new researchers a summary of the current state of art. The schemes are divided into four main categories: passivity based, prediction based, sliding-mode control schemes and others. The comparison is based on transparency level, stability requirement, delay type, and delay range