Presentation of the concept of stability of the hybrid powertrain by the Lyapunov theory

The paper presents an algorithm for controlling a hybrid drive system equipped with an internal combustion engine and electric motor. Work algorithm provides basic control of the petrol engine as the primary energy source. The internal combustion engine control system adopted an adaptive control system, which taking into account the stability of the system by Lyapunov allows for optimum combustion engine and electric motor. The direct method by Lyapunov stability analysis allows one to assess the stability of the whole system of hybrid propulsion system of a wheeled vehicl

Impact of the Selected Disturbing Factors on Accuracy of the Distance Measurement with the Use of Ultrasonic Transducers in a Hard Coal Mine

The article presents tests on the possibility of using ultrasonic transducers for accurate distance measurement in hard coal mines. In order to check the impact of selected disturbing factors on the measurement results, test stands were built, and then a full cycle of measurements with the use of different transducers (AR30 and AR41), which were selected and pre-tested in previous research projects, was realized. The impact of such disturbing factors as airborne dust (coal, stone, lime and mixed dust), changes in temperature and humidity on the propagation of ultrasonic waves, amplitude and measurement accuracy was investigated. The tests were preceded by theoretical analysis. It was found that the transducers selected for the tests had a sufficient accuracy and range, so they can be used in the devices planned to be designed, allowing for the determining of the location of a roadheader in hard coal mine roadways, taking into account technical and legal restrictions. It was also specified which disturbing factors should be compensated and what methods and parameters of this compensation should be used

Impact of the Selected Disturbing Factors on Accuracy of the Distance Measurement with the Use of Ultrasonic Transducers in a Hard Coal Mine

The article presents tests on the possibility of using ultrasonic transducers for accurate distance measurement in hard coal mines. In order to check the impact of selected disturbing factors on the measurement results, test stands were built, and then a full cycle of measurements with the use of different transducers (AR30 and AR41), which were selected and pre-tested in previous research projects, was realized. The impact of such disturbing factors as airborne dust (coal, stone, lime and mixed dust), changes in temperature and humidity on the propagation of ultrasonic waves, amplitude and measurement accuracy was investigated. The tests were preceded by theoretical analysis. It was found that the transducers selected for the tests had a sufficient accuracy and range, so they can be used in the devices planned to be designed, allowing for the determining of the location of a roadheader in hard coal mine roadways, taking into account technical and legal restrictions. It was also specified which disturbing factors should be compensated and what methods and parameters of this compensation should be used

The impact of the Coronavirus (COVID-19) Pandemic on Master graduates’ employability

The COVID-19 pandemic brought the global economy to a near standstill. The scale of the coronavirus and the associated losses have left many countries facing a humanitarian, social and economic crisis. The main objective of the research presented in this article was to determine to what extent the support provided within the activities of the Motokadra project (2018–2020) within the framework of the Operational Programme Knowledge Education Development, funded by the European Social Fund, enabled its participants to adapt to the labour market conditions during the COVID-19 pandemic. The project participants were full-time Master’s students within the faculty of Mechanical Engineering, Silesian University of Technology. They formed the experimental group. The authors examined changes in the employability of the experimental group in the pre-pandemic and post-pandemic periods. The students in the experimental group represented several fields of study, which also allowed the authors to analyse which discipline appeared to be more resilient to the COVID-19 pandemic crisis and whether the profile of the discipline affected employability. The employability of graduates in the automotive industry was particularly examined. The results of the analyses allow us to conclude that the labour market crisis linked to the COVID-19 pandemic negatively affected the experimental group’s employability level. Furthermore, it has been shown that the study of the automation and robotics discipline increases the chances of finding a job after graduation

Study of Energy Consumption of a Bucket Conveyor in a Jig Concentrator Plant in a Hard Coal Mine

The subject of the discussion is oriented toward limiting the energy consumption of the bucket conveyor used in jig concentrator plants by controlling its speed. A method of predictive control of the bucket conveyor speed is presented. It allows for reducing the energy consumption due to appropriate selection of bucket movement speed to ensure the nominal filling of buckets along the entire length of the conveyor. This approach enables limiting the idling speed of the conveyor, extend its life, and also reduce the electricity consumption of the entire system. Experimental studies, carried out at the “Sośnica” Coal Mine working facility, confirmed that the use of a predictive algorithm for controlling the bucket conveyor speed and adapting the bucket speed to the current load decreased in energy consumption n by 9.6%, with 80% of the filling conveyor