Test stand equipped with a polyharmonic vibration source to study compaction of dispersed material in an enclosed volume

This article discusses the work that resulted in the development of two battery-powered self-propelled electric mining machines intended for operation in the conditions of a Polish copper ore mine. Currently, the global mining industry is seeing a growing interest in battery-powered electric machines, which are replacing solutions powered by internal combustion engines. The cooperation of Mine Master, Łukasiewicz Research Network—Institute of Innovative Technologies EMAG and AGH University of Science and Technology allowed carrying out a number of works that resulted in the production of two completely new machines. In order to develop the requirements and assumptions for the designed battery-powered propulsion systems, underground tests of the existing combustion machines were carried out. Based on the results of these tests, power supply systems and control algorithms were developed and verified in a virtual environment. Next, a laboratory test stand for validating power supply systems and control algorithms was developed and constructed. The tests were aimed at checking all possible situations in which the battery gets discharged as a result of the machine’s ride or operation and when it is charged from the mine’s mains or with energy recovered during braking. Simulations of undesirable situations, such as fluctuations in the supply voltage or charging power limitation, were also carried out at the test stand. Positive test results were obtained. Finally, the power supply systems along with control algorithms were implemented and tested in the produced battery-powered machines during operational trials. The power systems and control algorithms are universal enough to be implemented in two different types of machines. Both machines were specially designed to substitute diesel machines in the conditions of a Polish ore mine. They are the lowest underground battery-powered drilling and bolting rigs with onboard chargers. The machines can also be charged by external fast battery chargers.

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Load Resistance Optimization of Bi-Stable Electromagnetic Energy Harvester Based on Harmonic Balance

Sensors ◽

10.3390/s21041505 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1505

Author(s):

Sungryong Bae ◽

Pilkee Kim

Keyword(s):

External Load ◽

Harmonic Balance ◽

Energy Harvester ◽

Load Resistance ◽

Electromagnetic Energy ◽

Analytic Approach ◽

Accurate Estimation ◽

Vibration Source ◽

Optimal Load ◽

Matching Techniques

In this study, a semi-analytic approach to optimizing the external load resistance of a bi-stable electromagnetic energy harvester is presented based on the harmonic balance method. The harmonic balance analyses for the primary harmonic (period-1T) and two subharmonic (period-3T and 5T) interwell motions of the energy harvester are performed with the Fourier series solutions of the individual motions determined by spectral analyses. For each motion, an optimization problem for maximizing the output power of the energy harvester is formulated based on the harmonic balance solutions and then solved to estimate the optimal external load resistance. The results of a parametric study show that the optimal load resistance significantly depends on the inductive reactance and internal resistance of a solenoid coil––the higher the oscillation frequency of an interwell motion (or the larger the inductance of the coil) is, the larger the optimal load resistance. In particular, when the frequency of the ambient vibration source is relatively high, the non-linear dynamic characteristics of an interwell motion should be considered in the optimization process of the electromagnetic energy harvester. Compared with conventional resistance-matching techniques, the proposed semi-analytic approach could provide a more accurate estimation of the external load resistance.

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Concept and Realization of a Novel Test Method Using a Dynamic Test Stand for Detecting Persons by Sensor Systems on Autonomous Agricultural Robotics

Sensors ◽

10.3390/s21072315 ◽

2021 ◽

Vol 21 (7) ◽

pp. 2315

Author(s):

Christian Meltebrink ◽

Tom Ströer ◽

Benjamin Wegmann ◽

Cornelia Weltzien ◽

Arno Ruckelshausen

Keyword(s):

Environmental Conditions ◽

Dynamic Test ◽

Test Methods ◽

Test Stand ◽

Human Detection ◽

Test Method ◽

Sensor Systems ◽

Functional Safety ◽

Agricultural Robots ◽

Agricultural Robotics

As an essential part for the development of autonomous agricultural robotics, the functional safety of autonomous agricultural machines is largely based on the functionality and robustness of non-contact sensor systems for human protection. This article presents a new step in the development of autonomous agricultural machine with a concept and the realization of a novel test method using a dynamic test stand on an agricultural farm in outdoor areas. With this test method, commercially available sensor systems are tested in a long-term test around the clock for 365 days a year and 24 h a day on a dynamic test stand in continuous outdoor use. A test over a longer period of time is needed to test as much as possible all occurring environmental conditions. This test is determined by the naturally occurring environmental conditions. This fact corresponds to the reality of unpredictable/determinable environmental conditions in the field and makes the test method and test stand so unique. The focus of the developed test methods is on creating own real environment detection areas (REDAs) for each sensor system, which can be used to compare and evaluate the autonomous human detection of the sensor systems for the functional safety of autonomous agricultural robots with a humanoid test target. Sensor manufacturers from industry and the automotive sector provide their sensor systems to have their sensors tested in cooperation with the TÜV.

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Predicting Dam Flood Discharge Induced Ground Vibration with Modified Frequency Response Function

Water ◽

10.3390/w13020144 ◽

2021 ◽

Vol 13 (2) ◽

pp. 144

Author(s):

Yan Zhang ◽

Jijian Lian ◽

Songhui Li ◽

Yanbing Zhao ◽

Guoxin Zhang ◽

...

Keyword(s):

Frequency Response ◽

Frequency Distribution ◽

Response Function ◽

Frequency Response Function ◽

Ground Vibration ◽

Vibration Source ◽

Ground Vibrations ◽

High Energies ◽

Flood Discharge ◽

Opening Method

Ground vibrations induced by large flood discharge from a dam can damage surrounding buildings and impact the quality of life of local residents. If ground vibrations could be predicted during flood discharge, the ground vibration intensity could be mitigated by controlling or tuning the discharge conditions by, for example, changing the flow rate, changing the opening method of the orifice, and changing the upstream or downstream water level, thereby effectively preventing damage. This study proposes a prediction method with a modified frequency response function (FRF) and applies it to the in situ measured data of Xiangjiaba Dam. A multiple averaged power spectrum FRF (MP-FRF) is derived by analyzing four major factors when the FRF is used: noise, system nonlinearity, spectral leakages, and signal latency. The effects of the two types of vibration source as input are quantified. The impact of noise on the predicted amplitude is corrected based on the characteristics of the measured signal. The proposed method involves four steps: signal denoising, MP-FRF estimation, vibration prediction, and noise correction. The results show that when the vibration source and ground vibrations are broadband signals and two or more bands with relative high energies, the frequency distribution of ground vibration can be predicted with MP-FRF by filtering both the input and output. The amplitude prediction loss caused by filtering can be corrected by adding a constructed white noise signal to the prediction result. Compared with using the signal at multiple vibration sources after superimposed as input, using the main source as input improves the accuracy of the predicted frequency distribution. The proposed method can predict the dominant frequency and the frequency bands with relative high energies of the ground vibration downstream of Xiangjiaba Dam. The predicted amplitude error is 9.26%.

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Design and Commissioning of a Modular Multi-Stage Two-Evaporator Transcritical CO2 Test Stand

International Journal of Refrigeration ◽

10.1016/j.ijrefrig.2021.05.033 ◽

2021 ◽

Author(s):

Riley B. Barta ◽

Davide Ziviani ◽

Eckhard A. Groll

Keyword(s):

Test Stand ◽

Multi Stage

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Multimodal pizza-shaped piezoelectric vibration-based energy harvesters

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x211006910 ◽

2021 ◽

pp. 1045389X2110069

Author(s):

Virgilio J Caetano ◽

Marcelo A Savi

Keyword(s):

Energy Harvesting ◽

Frequency Spectrum ◽

Optimization Procedure ◽

Single Mode ◽

Ambient Vibration ◽

Vibration Source ◽

Element Analysis ◽

Energy Harvesters ◽

Piezoelectric Energy ◽

Harvesting Systems

Energy harvesting from ambient vibration through piezoelectric devices has received a lot of attention in recent years from both academia and industry. One of the main challenges is to develop devices capable of adapting to diverse sources of environmental excitation, being able to efficiently operate over a broadband frequency spectrum. This work proposes a novel multimodal design of a piezoelectric energy harvesting system to harness energy from a wideband ambient vibration source. Circular-shaped and pizza-shaped designs are employed as candidates for the device, comparing their performance with classical beam-shaped devices. Finite element analysis is employed to model system dynamics using ANSYS Workbench. An optimization procedure is applied to the system aiming to seek a configuration that can extract energy from a broader frequency spectrum and maximize its output power. A comparative analysis with conventional energy harvesting systems is performed. Numerical simulations are carried out to investigate the harvester performances under harmonic and random excitations. Results show that the proposed multimodal harvester has potential to harness energy from broadband ambient vibration sources presenting performance advantages in comparison to conventional single-mode energy harvesters.

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Design of a Test Stand for Lifetime Assessment of Flat Belts in Power Transmission

Procedia CIRP ◽

10.1016/j.procir.2020.02.187 ◽

2020 ◽

Vol 91 ◽

pp. 356-361

Author(s):

Varun Urundolil Kumaran ◽

Markus Zogg ◽

Lukas Weiss ◽

Konrad Wegener

Keyword(s):

Power Transmission ◽

Test Stand

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DESIGN CONCEPT OF TEST STAND FOR DETERMINING PROPERTIES OF MAGNETORHEOLOGICAL ELASTOMERS

Acta Mechanica et Automatica ◽

10.2478/ama-2013-0022 ◽

2013 ◽

Vol 7 (3) ◽

pp. 131-134 ◽

Cited By ~ 2

Author(s):

Mirosław Bocian ◽

Jerzy Kaleta ◽

Daniel Lewandowski ◽

Michał Przybylski

Keyword(s):

Magnetic Field ◽

Mechanical Properties ◽

Smart Materials ◽

Vibration Damping ◽

Test Stand ◽

Design Concept ◽

Special Test ◽

Magnetorheological Elastomers ◽

Vibration Dampers

Abstract Magnetorheological elastomers (MRE) are “SMART” materials that change their mechanical properties under influence of magnetic field. Thanks to that ability it is possible to create adaptive vibration dampers based on the MRE. To test vibration damping abilities of this material special test stand is required. This article presents design concept for such test stand with several options of testing.

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