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Stepper motors are synchronous electric actuators with incremental displacement that can be controlled in open loop in position or speed. Unfortunately, the rotor oscillations that characterize stepper motors are a major handicap that limits the use of this type of actuator in precision industrial applications and especially in biomedical systems. Improving motor drive performance is challenging due to the presence of uncertainty in system parameters and large load variations. To overcome these problems and the shortcomings of conventional control approaches, a new control concept based on fuzzy logic is developed. To this purpose, this paper proposes a fuzzy logic concept (FLC) for damping rotor oscillations of stepper actuator devoted to an Electrical Syringe Pump application. The FLC membership functions and rules are designed with value normalization that allows the developed controller able to be flexible when applied to a wide range of applications. The proposed FLC is numerically validated. Critical testing scenarios are employed including motor inertia variation, supply voltage variation, fluid friction variation and for different loads. Moreover, thanks to its normalized design, the proposed FLC is not limited to the studied biomedical applications, but can be applied to other application systems. [ABSTRACT FROM AUTHOR]

There is limited research focused on achieving optimal torque control performance of Switched Reluctance Generators (SRGs). The majority of existing studies tend to favor voltage or power control strategies. However, a significant drawback of SRGs is their susceptibility to high torque ripple. In power generation systems, torque ripple implicates fluctuations in the generated power of the generator. Moreover, high torque ripple can lead to mechanical vibrations and noise in the powertrain, impacting the overall system performance. In this paper, a Torque Sharing Function (TSF) with Indirect Instantaneous Torque Control (IITC) for SRG applied to Wind Energy Conversion Systems (WECS) is proposed to minimize torque ripple. The proposed method adjusts the shared reference torque function between the phases based on instantaneous torque, rather than the existing TSF methods formulated with a mathematical expression. Additionally, this paper introduces an innovative speed control scheme for SRG drive using a Fuzzy Super-Twisting Sliding Mode Command (FSTSMC) method. Notably robust against parameter uncertainties and payload disturbances, the proposed scheme ensures finite-time convergence even in the presence of external disturbances, while effectively reducing chattering. To assess the effectiveness of the proposed methods, comprehensive comparisons are made with traditional control techniques, including Proportional–Integral (PI), Integral Sliding Mode Control (ISMC), and Super-Twisting Sliding Mode Control (STSMC). The simulation results, obtained using MATLAB®/SIMULINK® under various speeds and mechanical torque conditions, demonstrate the superior performance and robustness of the proposed approaches. This study presents a thorough experimental analysis of a 250 W four-phase 8/6 SRG. The generator was connected to a DC resistive load, and the analysis focuses on assessing its performance and operational characteristics across different rotational speeds. The primary objective is to validate and confirm the efficacy of the SRG under varying conditions. [ABSTRACT FROM AUTHOR]

The present paper deals with design, modeling and characteristics of a biomedical system. The involved biomedical system is a syringe pump generally used for continuous drug infusion. The syringe pump consists of a linear switched reluctance motor (LSRM) coupled to a syringe plunger. In order to determine the axial force to control the syringe plunger, it was necessary to begin by evaluating the thrust force. For that purpose, an analytical approach is developed to evaluate the different forces and pressures involved. In addition, an experimental bench was conceived to determine the thrust force and validate the analytical model of the syringe. Consequent results constituted the key element for designing and modeling the LSRM with the help of finite element methods (FEM). The final step is reserved to predict the dynamic performances of all the biomedical system with and without saturation. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The present paper deals with design, modelling and characteristics of a biomedical system. The involved biomedical system is a syringe pump generally used for continuous drug infusion. The syringe pump consists of a linear switched reluctance motor (LSRM) coupled to a syringe plunger. In order to determine the axial force to control the syringe plunger, it was necessary to begin by evaluating the thrust force. For that purpose, an analytical approach is developed to evaluate the different forces and pressures involved. In addition, an experimental bench was conceived to determine the thrust force and validate the analytical model of the syringe. Consequent results constituted the key element for designing and modelling the LSRM with the help of finite element methods (FEM). The final step is reserved to predict the dynamic performances of all the biomedical system with and without saturation. [ABSTRACT FROM AUTHOR]

This article explores the activity of canyoning in the natural territory of the Mercantour National Park (France). The investigation refers to the sociology of logics of action to understand the disparity of its development. The 85 canyons are explored according to their interest and their use. The interviews conducted with professionals and other actors in the mountain territories lead to the observation that despite a varied offer, made attractive by the presence of a natural park, only 16 canyons are regularly visited. This situation is the result of a controversy between the use that depends on the practitioners and the professionals who live there and the development of the canyons that depends on the political will of the local authorities. [ABSTRACT FROM AUTHOR]