The continuous monitoring systems developed for health and safety provisions in underground mines have always been a deep concern in mining activity, since this is one of the most dangerous work activities in the world. All mining activities must follow strict regulations that pose an increased responsibility for the design and implementation of novel technologies aiming to enhance both the workers’ and equipment’s safety in underground mines. Coal mines are some of the most dangerous, with high risk of explosion due to pit gas; therefore, we propose the use of visible light communication for local wireless transmission and optical fiber for remote-cabled transmission. We address, in this article, a complete system comprising real-time personnel tracking and environmental methane measurement, as well as the transmission of data, with a detailed explanation of the complete system and technical description with practical solutions applicable for industrial use.

Significant implementations and encouraging results have already been achieved using visible light communication (VLC) technology for different applications from indoor to free space optics (FSO) and even underwater communication. The LED light fixtures are about to be used with dual functionality - illumination and fast wireless data communication - and when the technology will become mature enough, the general costs for both will considerably decrease. However, especially due to a complex multipath channel impulse response (CIR) evaluation, there are few research in VLC applied in industrial environments. At the same time, in the non-Line of Sight (NLoS) VLC setup with mobile optical transmitter (oTx) and fixed optical receiver (oRx) considered here, both the path loss and multipath-induced dispersion significantly limits the link performance. In this paper, we investigate the CIR into indoor industrial environments. We take into consideration both Intrinsic Optical Properties in Industrial Environments (IOPIEs) and Apparent Optical Properties (AOPs) in Industrial Environments. The VLC setup complexity such as oTx and oRx position and orientation, the geometry and the nature of the indoor surfaces (diffuse or specular) and appropriate positioning of both oTx and oRx required for a suitable implementation of the VLC. The VLC system proposed is also investigate in this work based on data acquisition, simulation and analysis according the ARX mathematical model.

This paper presents an analytic method of controllers tuning for the speed vector control of induction motor drive system. The control system is on with orientation after the rotor flux. The controllers tuning is made analytical, by using the poles-zeros methods and the symmetry and modulus criterion, the Kessler variant.

Within this work we present a method of choosing the proportionality coefficient between the eigenvalues of the motor and the eigenvalues of the Luenberger Observer. The choosing of this coefficient is made based on the Routh-Hurwitz criterion considering that the controller within the adjustment mechanism is an adaptive type one. The tuning of the PI controller within the adjustment mechanism is made based on the proportionality coefficient between the eigenvalues of the motor and the eigenvalues of the observer. All these research are made in order to stabilize the control system at low speed both in motor and in regenerating mode running. On the other hand within this work we present in details the current, flux, torque and speed controllers' tuning within the control system. In the end paper we analyze the asymptotic stability of a vector control system for an induction motor with short-circuited rotor that contains in its loop an extended Luenberger observer. The studied control system is based on the direct rotor flux orientation method (DFOC) and the stability study is based upon the linearization theorem around the equilibrium points of the control system, emphasizing the estimated variation domain of the rotor resistance for which the control system remains asymptotically stable.

The paper presents a synthesis of an extended Gopinath observer (EGO) and analyzes the asymptotic stability of a squirrel-cage induction motor vector control system with an EGO in its ...