Laboratory Test Bench Research Articles

Use of the Long-Wavelength Range for Remote Sensing of Atmospheric Aerosols

The results of laboratory experiments on recording the backscattered IR laser radiation from aerosol particles which contain organic impurities are presented. The studies were performed at the laboratory test bench according to the lidar sensing scheme along a controlled optical path. Water aerosol and water solutions with organic impurities (tryptophan, isopropyl alcohol, glycerin, and nicotinamide adenine dinucleotide (NADH)) were used as model media. A possibility of using IR lasers with frequency scanning for remote sensing of atmospheric organic aerosols is shown.

Influence of vertical and horizontal whole-body vibration on selected muscles tension of employees age 50+ in relation to professional exposure to vibration (pilot study)

The pilot study on changes of selected muscles tension caused by vertical and horizontal whole-body vibration focused on employees belonging to two professional (occupational) groups. One of these groups consisted of men aged 50 years professionally exposed to vibration and the second were men not exposed to vibration at the workplace. Tests have been conducted in two series on special designed laboratory test bench for simulation of exposure to whole-body vibration. During the I series of tests, vertical vibration had acted on subjects and during II series horizontal lateral vibration had acted. The EMG signals were registered from muscles of the shoulder girdle and lower back, both sites of the body. Muscles tension values obtained during I and II series indicates that there are no statistical significant differences between reaction of subjects on vertical and horizontal vibration. However slightly lower EMG RMS values during II series were noticed. Exposure to whole-body vibration may cause changes in muscle tension both in employees (aged 50 years and older) occupationally exposed to vibration and not exposed to vibration. The observed changes vary in both groups of subjects. In occupationally exposed to vibration subjects the impact of exposure to vibration on muscle tension is less than in reference group.

Research on energy-saving characteristics of battery-powered electric-hydrostatic hydraulic hybrid rail vehicles

With the advantages of no emission and low noise, battery rail vehicles (BRVs) are widely used in the construction of subway, high-speed railway and so on. However, the problems of low energy efficiency and peak power shock of traction motor have severely restricted the application and promotion of BRVs. To address these problems, an electric-hydrostatic hydraulic hybrid powertrain (EH3) is designed in this paper. Friction braking (FB) is replaced by hydraulic regenerative braking (HRB) and the mode of recovered hydraulic energy coupled at the inlet of pump (ECIP) to assist acceleration is proposed. The energy conservation characteristics of recovery and coupling of hydraulic energy in EH3 powertrain are verified by simulation and laboratory test bench. The energy recovery efficiency of HRB is up to 50% and the new coupling modes can greatly reduce the consumption of electric power. The control strategy is designed to coordinate different working modes which are established based on the high-pressure accumulator (HPA) and the driving state parameters of BRVs. The simulation result shows that the energy consumption of the battery can be reduced by 17.32%. The EH3 powertrain has broad application prospects in realizing energy conservation, reducing peak motor power shock and improving the braking performance of BRVs.

Estimation of inverter voltage disturbances for induction machine drive using LPV observer with convex optimization

This paper presents a Linear Parameter-Varying (LPV) observer for an Induction Machine (IM) under sinusoidal DC-supply disturbances. The observer estimates not only the IM state variables, but also the disturbances considered as a part of the states. As the extended IM model depends on the stator angular speed ωs and the rotor angular speed ωr, the proposed observer is designed by convex optimization to induce a convergence of the observer for a predetermined range of ωs and ωr. The estimated disturbances can be used to compensate for the real disturbances. The simulation results show the effectiveness of the observer, and experimental results on a laboratory test-bench have been obtained. The proposed method can be extended to other type of motor drives.

Correction of non-common path aberrations in pyramid wavefront sensors to recover the optimal magnitude gain using a deformable lens.

Adaptive optics (AO) correction based on pyramid wavefront sensors (P-WFSs) has been successfully implemented in several instruments for astronomical observation due to the P-WFS advantages in terms of sensitivity with respect to other WFSs, such as the Shack-Hartmann. The correction of non-common path aberrations (NCPAs) between the sensing and the scientific arm, commonly performed introducing offsets to the Zernike coefficients of the measured wavefront in the AO closed loop, reduces the sensitivity of P-WFSs causing a loss in sky coverage and scientific throughput. We propose a technique to exploit the full capabilities of P-WFSs compensating the NCPAs up to the fourth order on the WFS channel by means of a multi-actuator adaptive lens (MAL). We show the preliminary results obtained in a dedicated laboratory test bench.

In brief

PAGE 632 Chinese researchers propose a symbol cyclic reconstruction scheme for universal-filtered multi-carrier systems (UFMC). The overlap-add technique is used to lower the computational complexity of the system transmitter, with ISI cancellation used at the receiver to remove interference between neighbouring symbols. Simulation results show the superiority of the scheme over state-of-the-art systems. PAGE 616 Researchers from Iran present a monitoring technique for tracking the state-of-health of batteries, suitable for use in battery management systems. The method can detect early degradation of batteries by monitoring the switching and battery transitions in a battery management system. Experiments on a typical charge balancing circuit verify the performance of the technique. Block diagram of SCR-UFMC with multipath fading channels. PAGE 589 Indian researchers propose a novel estimation technique for a noise-influenced electronic circuit, unifying the Carleman linearisation with the Fokker-Planck equation for Itô's Stochastic Differential Equations. Numerical simulation results are presented for a benchmark tunnel diode oscillator circuit. The method may prove useful for estimating state trajectories under the influence of randomness when observations are not possible. Laboratory test bench. PAGE 612 A collaboration of researchers from Japan present an evaluative study on the current and luminance characteristics of powder electroluminescent devices prepared on gravure offset-printed invisible Ag-grid electrodes. Results show that the luminance is strongly dependent on the transparency and light-extraction efficiency of the Ag-grid electrodes. Flow of the proposed estimation technique.. PAGE 609 Researchers from China propose a wideband differential filtering power divider, using a three-lined coupled structure with multiple lumped elements. Compared with other differential filtering power dividers, the proposed design shows the advantages of a wide bandwidth, compact size and low insertion loss. A prototype validates the simulated results. Optical microscopy image of the emitted light from PELDs on the Ag-grid electrodes. Photograph of the proposed wideband differential filtering power divider.

Design of fractional delay repetitive control with a dead-beat compensator for a grid-tied converter under distorted grid voltage conditions

The paper presents the design of a current control system of a grid-tied converter which provides high dynamic in transients states and symmetrical sinusoidal currents under distorted and asymmetrical grid voltage conditions. The current control loop contains a dead-beat compensator and a plug-in fractional delay repetitive controller. The whole control system is designed with regard to signal processing delay present in the control loop. The tuning procedure of the repetitive control uses particle swarm optimization to determine the optimal gain, phase lead and filter parameter. The resulting control system with optimal parameters is applied on the digital signal controller and verified experimentally on the laboratory test bench, which is the main contribution of the paper.

Bench test of microwave imaging reflectometry system for EAST tokamak

Microwave Imaging Reflectometry (MIR) has been developed for measuring two-dimensional electron density fluctuations on many Tokamaks. A MIR system with 96 pixels (12 poloidal × 8 radial) has been fabricated for EAST tokamak. In the paper, we present the evaluation results in laboratory bench test with details, including performance of the electronic system and optics. With an artificial target as the real plasma cutoff layer, it has been proved that the EAST MIR system has the capability to reconstruct the correct corrugated shape of cutoff layer.

Опыт создания лаборатории судовых вспомогательных механизмов для обучения судовых механиков в ФГБОУ ВО «АГТУ»

The article focuses on the functional capabilities, technical characteristics and bench composition of the laboratory of ship auxiliary mechanisms, which was created at the Department of Operation of Water Transport at the Astrakhan State Technical University (ASTU) for training marine engineers. The laboratory provides the students with professional competencies in such aspects of the mechanical engineer’s operation as ship turbo machines, ship auxiliary mechanisms and systems, automatic control systems, operation of ship boiler rooms and steam generating plants, etc. There have been presented the pictures of laboratory test benches for testing the P01 ship steering machine and ЯШ-2Р anchor mooring pin, РCC-6.3/10 ship fan, TKР-700 turbo compressor, gear fuel pump Ш5-25-3Б, prototypes of TГ-16M gas turbine generator and ГTД-16M gas turbine engine. Using the laboratory test benches for auxiliary mechanisms and systems helps to both consolidate the theory and gain the new practical knowledge on the design, operation principles and testing skills of the ship steering machine, deck equipment, ventilation systems gear pumps, turbochargers, etc. It has been stated that all the laboratory facilities, except for the GD-IN model (facilities for studying the pump operation and constructing pressure-flow characteristics), were developed and assembled by the students and teachers on the basis of the real ship equipment. The laboratory tests are based on regulatory and technical documents: the rules of the Russian Maritime Register of Shipping, machine operating instructions, relevant GOSTs, guidance and regulatory documents. Building the laboratory of auxiliary mechanisms and systems and optimizing the time for practical and laboratory training of ship mechanical engineers at ASTU were carried out in accordance with the requirements of the new educational standard GEF 3++ of higher education and the International Convention on Training and Certification of Sailors and Watchkeeping (The Manila amendments to the STCW Convention and Code).

A Holistic View on Urea Injection for NOx Emission Control: Impingement, Re-atomization, and Deposit Formation

The injection of urea-water solution (UWS) sprays into engine-close selective catalytic reduction (SCR) systems faces developers with complex challenges regarding two-phase flow and deposit formation. Potential spray impact on the static mixing elements inside the exhaust duct can lead to accumulation of liquid film and solid deposits, which may result in detachment of large UWS droplets at the trailing edges of the mixer blades. Present work focuses on the mechanisms of film and deposit formation within the scope of a joint study on spray preparation in the mixing section of SCR systems. A production type SCR exhaust system is used for optical investigations on gas flow and UWS droplets at the mixing element using Laser Doppler Anemometry (LDA) and Long Distance Microscopy (LDM) with a high-speed camera. Measured shear flows inside the mixing element are up to three times higher than the flow velocity upstream the mixer. Here, a decrease of droplet diameters of detached droplets is revealed with increased shear flow velocity. Characteristic urea deposits are created in a laboratory test bench and their surface structure is measured by use of Confocal Microscopy. Results show highly rough surface structures, which are used as input parameters together with the flow measurements to define the computational domain at the trailing edge of the mixer blades. Smoothed Particle Hydrodynamics (SPH) method is adopted for the numerical simulation of the transient two-phase flow and validated by LDM high-speed recordings of droplet detachment. Comparisons reveal a distinct influence of solid depositions on the re-atomization of the liquid film at the rear edge of the mixer blade. By interface resolving simulations with a phase-field method, the wall impingement of a sequence of large secondary droplets and associated film formation are studied. The results indicate that UWS film formation at the exhaust pipe wall may be reduced by hydrophobic surfaces and high gas velocities near the wall.

Development of solid anti-friction elements for greasing the ridges of locomotive wheel pairs

Design work was carried out to develop solid anti – friction elements for greasing the ridges of locomotive wheel pairs (hereinafter referred to as TAEL rods). The results of laboratory bench and operational tests of TAEL rods were obtained in accordance with the procedure for admission of lubricants for the wheel-rail contact to use in grebnesmazyvatelyami lo-comotives operated on the Railways of the Russian Federation . Based on the test results, the developed TAEL rods were approved for use on the infrastructure of Russian Railways.

PGM based catalysts for exhaust-gas after-treatment under typical diesel, gasoline and gas engine conditions with focus on methane and formaldehyde oxidation

The HC and CO oxidation activity of Pt/Al2O3, Pd/Al2O3 and Pd-Pt/Al2O3 catalysts was compared under three exhaust-gas model conditions typical for stoichiometric gasoline as well as lean burn diesel by means of temperature programed conversion tests on laboratory test benches. In order to understand the differences in emission reduction performance, the impact of gas mixture composition was systematically studied with a particular focus on methane and formaldehyde conversion.The catalysts used in this study were prepared by incipient wetness impregnation of Al2O3 followed by washcoating on ceramic honeycombs, and were pre-treated in an equal manner before each activity test.Distinct differences in pollutant conversion were observed over the three catalysts under the investigated conditions. Pd-based monometallic and bimetallic catalysts revealed the lowest temperature for CH4 oxidation (<450 °C) under lean conditions, being lower under lean Diesel than Compressed Natural Gas (CNG) conditions. The reason for this behavior seems to be the higher water concentration in the CNG gas mixture. Furthermore, it was found that the presence of HCs shifts the conversion of methane to higher temperatures, most probably due to produced water during combustion of the HCs. Pt/Al2O3 on the other hand only converts methane at temperatures above 500 °C but no sensitivity to water or the amount of additional HCs was observed. The lowest light-out temperature for formaldehyde oxidation in excess of oxygen was measured on Pt/Al2O3 with full conversion below 125 °C. While this was the case for a model gas mixture of HCHO, H2O and O2, under simulated lean burn gas engine conditions, formaldehyde is oxidized at lower temperature on Pd-Pt/Al2O3 than on Pt/Al2O3 due to the strong inhibiting effect of CO on Pt-particles.Under stoichiometric gasoline conditions, Pt had the highest activity for methane oxidation whereas Pd/Al2O3 and Pd-Pt/Al2O3 hardly convert methane below 500 °C. Unsaturated HCs and CO on the other hand were converted at lower temperature over Pd containing monometallic and bimetallic catalysts in comparison to Pt/Al2O3, showing once again the multiple and complex effects generated by variations in exhaust gas mixture and catalyst composition.

Function Development With an Electric-Machine-in-the-Loop Setup: A Case Study

In order to reduce automotive development times and costs, particular development tasks are rescheduled to earlier program phases (frontloading) by applying hardware-in-the-loop (HiL) tests. However, there is a shortage of studies considering HiL tests for function developments considering the thermal behavior of electric drives. This article shall be a first step toward closing this gap. A real-time co-simulation of a battery electric vehicle and a driver model are developed and connected to an electric traction machine at a laboratory test bench. A thermal derating function is designed and calibrated at this test setup. In particular, linear derating functions with different gradients are implemented and tested for high load performances during a track race, and the trade-off between energy demand and the lap time is determined. Larger gradients of thermal derating functions lead to shorter lap times and higher energy demands. Thus, for this case study, an increase of the gradient of the thermal derating function by a factor of two results in a lap time improvement of 2.3% and a higher energy demand of 4.7%. The test results demonstrate how HiL setups offer a favorable testing scenario to calibrate thermal derating functions of electrified powertrains in early development phases.

Reactive power analysis and frequency control of autonomous wind induction generator using particle swarm optimization and fuzzy logic

Wind generation system is becoming increasingly important as renewable energy sources due to its advantages such as low maintenance requirement and mainly it does not cause environmental contamination. This paper presents the improvement procedure of the transient state and the regulation of the output frequency by adjusting the terminal capacitor. The aim is to provide frequency control of a self-excited induction generator in remote site using different strategies which are based on the adjustment of the reactive power at the outputs of a three-phase self-excited induction generator. A thyristor controlled reactor and a switched resistive load will be used to control reactive power. The proposed particle swarm optimization algorithm technique, location of the thyristor controlled reactor device, and parameter value are optimized simultaneously. The results obtained by this strategy will be compared with those provided by the use of Fuzzy Logic Controller. This study will be conducted through the analysis of the frequency in the steady state and transient case using a developed induction generator numerical model built using MATLAB/Simulink. Simulation and experimental results will be exposed and analyzed considering a resistive inductive load on a laboratory test bench.

Ball on the plate balancing control system

The problem of balancing is a continuous study challenge for application in many spheres of interest from education to transportation. Two-degree of freedom ball balancing laboratory test bench is an important plant for control systems understanding. This paper focuses on the mechanical design and control algorithm of balancing a ball on a plate. The plant was equipped with resistive touch screen for ball position data acquisition, stepper motors with position sensors for platform inclination angle feedback data and AVR microcontroller-based two-loop subordinate control system with PID controllers for ball position maintaining. The laboratory bench was designed and assembled in Saint Petersburg Electrotechnical University “LETI” at the Automatic control systems department.

Scaling of the Drive Train Dynamics of Large-Scale Wind Turbine Systems for Real-Time Emulation in Small-Scale Laboratory Setups

The nonlinear state-space dynamical model of the drive train of large-scale wind turbine systems (WTSs) and its scaling for small-scale real-time WTS emulation in the laboratory are discussed in this paper. Shaft elasticity and the nonlinear, aerodynamical turbine torque are considered. To allow for a physically reasonable emulation of the dynamical behavior of multimegawatt wind turbine drive trains at a small-scale laboratory test bench, a general scaling method is presented, which is based on the ratios of physical SI-units. Furthermore, inertia emulation, elasticity emulation, and friction compensation are addressed and possible implementations are proposed. Simulation results of the full-scale WTS model and measurement results of the small-scale real-time WTS emulation are compared to illustrate the effectiveness of the proposed scaling.

Design and downhill speed control of an electric-hydrostatic hydraulic hybrid powertrain in battery-powered rail vehicles

The diesel-driven rail vehicles are gradually replaced by battery-powered rail vehicles (BRVs), due to its exhaust emissions and noise. However, the development of BRVs have two aspects that need improvement: low energy efficiency and poor downhill stability. To address these problems, this paper presents the design and downhill speed control of an electric-hydrostatic hydraulic hybrid (EH3) powertrain, which is mainly composed of a variable pump, a variable pump/motor, a proportional flow control valve (PFCV) and accumulators. Through a laboratory test bench, the hydraulic regenerative/non-friction braking performance of an EH3 powertrain is validated and experimentally analyzed. The hydraulic average energy recovery rate could be 50%. The method of downhill speed control is proposed, which is validated by the simulation results. During the downhill process, EH3 rail vehicle has a relatively high energy efficiency, which will bring good economic benefits in energy conversation and environmental protection.

The Novel Rotor Flux Estimation Scheme Based on the Induction Motor Mathematical Model Including Rotor Deep-Bar Effect

During torque transients, rotor electromagnetic parameters of an induction motor (IM) vary due to the rotor deep-bar effect. The accurate representation of rotor electromagnetic parameter variability by an adopted IM mathematical model is crucial for a precise estimation of the rotor flux space vector. An imprecise estimation of the rotor flux phase angle leads to incorrect decoupling of electromagnetic torque control and rotor flux amplitude regulation which in turn, causes deterioration in field-oriented control of IM drives. Variability of rotor electromagnetic parameters resulting from the rotor deep-bar effect can be modeled by the IM mathematical model with rotor multi-loop representation. This paper presents a study leading to define the unique rotor flux space vector on the basis of the IM mathematical model with rotor two-terminal network representation. The novel rotor flux estimation scheme was validated with the laboratory test bench employing the IM of type Sg 132S-4 with two variants of rotor construction: a squirrel-cage rotor and a solid rotor manufactured from magnetic material S235JR. The accuracy verification of the rotor flux estimation was performed in a slip frequency range corresponding to the IM load adjustment range up to 1.30 of the stator rated current. This study proved the correct operation of the developed rotor flux estimation scheme and its robustness against electromagnetic parameter variability resulting from the rotor deep-bar effect in the considered slip frequency range.

Dynamic Processes in Vacuum Contact Devices of Robots for Vertical Motion in the Water Environment

The results of experimental investigation intended to improve movement conditions for pneumatic robots on vertical surfaces under water are discussed. Features of the movement of vacuum contact devices for the simulation of mathematical model of the vacuum contact device with surfaces under water are presented. The experimental studies made it possible to obtain additional data on the dynamics of attachment, to obtain transient processes for air-water flow through ejector and to correct the results obtained earlier. For the purpose of analytical study of dynamic processes occurring in the system of vacuum contact devices, and taking into account the complexity of the description of nonlinearities, linearized simplified models of the system "air ejector — contact device — water environment" were developed. Vacuum contact devices are designed to provide guaranteed contact with vertical surfaces, plane slopes or horizontal surfaces on which the underwater robot performs its movement, carrying out the prescribed technological tasks, for example, in dry wells of nuclear power plants, on the surfaces of ship hulls, on the surfaces of underwater structures. The models took into account the forces of adhesion to the surfaces under water — the forces from the pressure drop, the friction force, the contact and vacuum interaction, the elasticity of suction caps. As a result of the solution of the model problem, the values of mechanical parameters, as well as the values of vacuum and flow in the cavity of variable volume as functions of changing the gap between the end of the corrugated membrane and the surfaces are obtained explicitly. As a result of the study of dynamic processes occurring in simplified models of vacuum contact devices "air ejector — contact surface — water environment", the transient characteristics of the change in the operating forces and pressures over time, as well as the dependence of the normal and tangential components of the forces on the depth of immersion in water were obtained. The variants of the designs of vacuum contact devices with surfaces in the water environment are investigated, and the modernization of the laboratory test bench for testing vacuum contact devices under water is carried out.

A Vision-Based Technique for in-Flight Measurement of Helicopter Blade Motion

The measurement of helicopter main rotor blade angles during flight is a key capability to implement advanced applications, such as strategies for the reduction of emitted noise and to develop innovative flight control laws. The approach proposed in this work for the real-time estimation of blade angles is based on a stereoscopic system mounted on the top of the main rotor and pointing to an optical target placed on the blade root. An advanced image-processing algorithm was developed to match the target features in the left and right camera images, which was required for the 3D reconstruction of the target based on a triangulation method. This algorithm was customized for the target used in this specific application, in order to implement a procedure that is both reliable in blob matching and characterized by a very low computation effort. This allowed the system to speed up the triangulation procedure aimed at obtaining the 3-D coordinates of the features, in view of real-time applications, even with very compact processing units that can be accommodated on the main rotor head. An inverse problem for the 3-D rotation of the target was solved using the Singular Value Decomposition technique, thus improving the robustness of the measurement. The stereoscopic system was developed in order to be integrated on board an AW139 helicopter main rotor hub, equipped with a synchronous lighting device and a pre-processing unit. The latter enabled the system to automatically extract the minimum set of information to be transferred, by means of a slipring, to the processing unit hosted in the fuselage. For the full assessment of the reliability and accuracy of the integrated system, harsh dynamic and accuracy trials were conducted on laboratory test benches. The harsh dynamic tests demonstrated that the system can work continuously in realistic conditions without any structural or data acquisition problems. The accuracy tests, based on a robot test rig simulating the motion of the blade, demonstrated the capability of the system and the accuracy of the measurement technique developed. The discrepancy between the reference blade angles and the estimated ones was found to be less than 0.360 for all the realistic blade angle combinations tested.