Search results for "Control theory"
showing 10 items of 1333 documents
Localization from inertial data and sporadic position measurements
2020
International audience; A novel estimation strategy for inertial navigation in indoor/outdoor environments is proposed with a specific attention to the sporadic nature of the non-periodic measurements. After introducing the inertial navigation model, we introduce an observer providing an asymptotic estimate of the plant state. We use a hybrid dynamical systems representation for our results, in order to provide an effective, and elegant theoretical framework. The estimation error dynamics with the proposed observer shows a peculiar cascaded interconnection of three subsystems (allowing for intuitive gain tuning), with perturbations occurring either on the jump or on the flow dynamics (depen…
Nonlinear Sculpturing of Optical Pulses in Fibre Systems
2019
The interplay among the effects of dispersion, nonlinearity and gain/loss in optical fibre systems can be efficiently used to shape the pulses and manipulate and control the light dynamics and, hence, lead to different pulse-shaping regimes [1,2]. However, achieving a precise waveform with various prescribed characteristics is a complex issue that requires careful choice of the initial pulse conditions and system parameters. The general problem of optimisation towards a target operational regime in a complex multi-parameter space can be intelligently addressed by implementing machine-learning strategies. In this paper, we discuss a novel approach to the characterisation and optimisation of …
Exposure to nanoparticles in thermal spraying - Vigilance towards the operator and the outside environment
2021
International audience; The previous survey of the French CaRPE project has shown a lack of information and showed the interest to assess the residual exposure to these particles. This paper presents the results of various sampling operations and emission analyses of plasma spraying equipment. For this purpose, different areas have been targeted, such as at the level of the emissions channeled upstream and downstream of the filtration system, at the workstation level as well as fugitive emissions. Various measurements were carried out: real-time particle size distribution, mass concentration of total suspended dust, heavy metals, sampling characterization by EDX/ MET, etc. The metallic aero…
Taking action or thinking about it? : State orientation and rumination are correlated in athletes
2019
Athletic performance in competitive sports relies heavily on the ability to cope effectively with stressful situations. In contrast, some athletes report that their thoughts revolve around the future or past and not around the actual demands during competitions. In those specific stressful situations, the lack of focus like an unintended fixation on repetitive cognitions can have fatal consequences with regard to the performance. Especially when competitors are close in their athletic capabilities, differences in effectively coping with stress and mental stability may decide about winning and losing. One established factor of performing effectively under pressure is the individual tendency …
Development and pilot-scale validation of a fuzzy-logic control system for optimization of methane production in fixed-bed reactors
2018
International audience; The objective of this study was to develop an advanced control system for optimizing the performance of fixed-bed anaerobic reactors. The controller aimed at maximizing the bio-methane production whilst controlling the volatile fatty acids content in the effluent. For this purpose, a fuzzy-logic controller was developed, tuned and validated in an anaerobic fixed-bed reactor at pilot scale (350 L) treating raw winery wastewater. The results showed that the controller was able to adequately optimize the process performance, maximizing the methane production in terms of methane flow rate, resulting in an average methane yield of about 0.29 LCH4 g−1 COD. On the other han…
Global linear feedback control for the generalized Lorenz system
2006
Abstract In this paper we show how the chaotic behavior of the Chen system can be controlled via feedback technique. We design both a nonlinear feedback controller and a linear one which globally regulate the closed-loop system states to a given point. We finally show that our approach works also for the whole family of the generalized Lorenz system.
Nonlinear Feedback Control and Stability Analysis of a Proof-of-Work Blockchain
2017
In this paper a novel feedback controller and stability analysis of a blockchain implementation is developed by using a control engineering perspective. The controller output equals the difficulty adjustment in the mining process while the feedback variable is the average block time over a certain time period. The computational power (hash rate) of the miners is considered a disturbance in the model. The developed controller is tested against a simulation model with constant disturbance, step and ramp responses as well as with a high-frequency sinusoidal disturbance. Stability and a fast response is demonstrated in all these cases with a controller which adjusts it's output at every new blo…
Transitions from grid-connected to island operation of Smart Microgrids
2019
In this paper a control methodology is presented to perform a bumpless transition from the on-grid to the offgrid of a smart microgrid. The derived controller manages the internal production in order to get to zero the tie-line active and reactive power flows so that the opening of the tie line breaker does not produce significant perturbations. Experimental tests performed on the microgrid built at the Polytechnic University of Bari demonstrated the effectiveness of the proposed control strategy.
Overview and experimental analysis of MC SPWM techniques for single-phase five level cascaded H-bridge FPGA controller-based
2016
This paper presents an overview and experimental analysis of the MC SPWM techniques for single-phase cascaded H-bridge inverter. The multilevel power converters are an alternative to traditional converters known as “three-level converters”. The voltage waveforms and the related frequency spectra, which have been obtained by simulation analysis in Matlab-Simulink environment, are here reported for all the proposed modulation techniques. The simulation results have been experimentally validated through means of a DC/AC, five-level, single-phase converter prototype with an appropriate test bench.
Further Results on Modeling, Analysis, and Control Synthesis for Offshore Wind Turbine Systems
2014
Renewable energy is a hot topic all over the world. Nowadays, there are several sustainable renewable power solutions out there; hydro, wind, solar, wave, and biomass to name a few. Most countries have a tendency to want to become greener. In the past, all new wind parks were installed onshore. During the last decade, more and more wind parks were installed offshore, in shallow water. This chapter investigates a comparative study on the modeling, analysis, and control synthesis for the offshore wind turbine systems. More specifically, an \( {\mathcal{H}}_{\infty } \) static output-feedback control design with constrained information is designed. Constrained information indicates that a rema…