High Speed Range Research Articles

An innovative ease-off flank modification method based on the dynamic performance for high-speed spiral bevel gear with high-contact-ratio

To reduce the running vibration of spiral bevel gear, an innovative ease-off flank modification method based on the dynamic performance for spiral bevel gear to minimize loaded transmission error (main vibration excitation of gear transmission in low speed range) and meshing impact (main vibration excitation of gear transmission in high speed range) is proposed. First, an innovative wave flank modification method related to high contact ratio, where the concave transmission error is used to replace the parabola transmission error, is proposed to minimize the loaded transmission error of high-contact-ratio spiral bevel gear. Secondly, meshing impact is calculated by considering the base pitch difference generated from loaded deformation. Finally, based on the advanced ease-off technology and wave flank modification method, an optimization model is established to reduce the loaded transmission error and meshing impact of high-speed spiral bevel gear with high-contact-ratio. The numerical results show that compared with optimized second-order spiral bevel gear transmission, the innovative ease-off flank modification method can further reduce the loaded transmission error and meshing impact of high-speed spiral bevel gear with high-contact-ratio, which greatly improves the dynamic performance of high-speed spiral bevel gear in the entire speed range.

A High Speed and Wide Frequency Division Range Mixed-Signal Pulse Swallow Frequency Divider for Phase-Locked-Loop

A frequency divider for a high speed and wide band Phase- Locked-Loop (PLL) which output frequency range is from 6 GHz to 12.5 GHz, is described. The designed mixed-signal swallow pulse divider mainly includes a divide-by-8/9 dual-modulus prescaler which is based on source coupled logic (SCL) structure for achieving high speed frequency division, and a 3-bit swallow counter and an 8-bit programmable counter to achieve wide range division ratio. This divider is fabricated in 65nm CMOS process and the power supply voltage is 1.25 V. The simulation results show that the power consumption of this divider is 5.34 mW. And the divider can achieve a continuous integer division ratio from 72 to 2047 in the PLL tuning range.

On the issue of choosing vertical and horizontal connections in a bogie for freight cars of high-speed trains

To increase the competitive advantages of rail freight transportation, the long-term development program of the Russian Railways provides for an increase in the speed of freight trains. The design speed of freight cars currently operating on the railway network is mainly 120 km/h, and the permitted speed is limited to 90 km/h. One of the possible solutions to the problem is the introduction of freight cars with an increased speed. At JSC “VNIIZHT” and JSC “VNIKTI”, work is being carried out on the selection of structures, the development of safety requirements, theoretical and experimental studies of freight traffic at increased speeds. In 2017—2018 at the Belorechenskaya—Maikop high-speed test range of the North Caucasian Railway, specialists of JSC “VNIIZHT” carried out running tests of a prototype of a platform car for transporting containers with a design speed of 160 km/h, developed by JSC “VNIKTI”. In the design of the platform car, a bogie is used, which is an analogue of the bogie of trailed cars of electric trains ED4 and ED9, with the selection of the stiffness of the springs in the spring suspension steps to comply with the difference in the level of the automatic coupler from the rail head in the “container” and “gross” modes. Analysis of the results of running tests allows determining the ways to improve the design of the bogie. To select design solutions for the purpose of ensuring safety, a review of the studies of domestic scientists aimed at studying the dynamic properties of railway rolling stock with various designs of the carriage part was carried out. Tests were carried out on prototypes of rolling stock having different elastic-dissipative connections in the “body-bogie-wheelsets” system. Based on the results of the analysis, design solutions have been determined that allow achieving satisfactory dynamic qualities for a freight car at a speed of up to 140 km/h. The adopted design solutions were tested on the basis of the results of theoretical studies of the dynamic properties of a platform car with a new bogie, carried out by the method of computer simulation. Increasing the flexibility of the spring suspension and the horizontal connection of the body with the bogie made it possible to improve the dynamic qualities of freight cars. To assess the safety during certification, it is required to develop a standard that would take into account the design features of car bogies, designed for increased speed.

Deep-sea <i>in-situ</i> laser Doppler velocity measurement system

A set of 4000-meter laser Doppler hydrothermal velocity measurement prototype suitable for deep sea <i>in-situ</i> measurement is developed in this work. In the system, an integrated design is adopted. The system is composed of a light source module, an optical module, and a Doppler signal processing module. The system is encapsulated in a pressure chamber with <i>L</i>500 mm × <i>Φ</i>205 mm to form an integrated optical measuring probe. An optical path of two-beam laser Doppler velocity measurement with strong local oscillator is proposed. The prototype is used to measure the simulated velocity in the laboratory. The measurement range is 0.01–10 m/s, and the flow velocity measurement resolution is 0.001 m/s. The experimental results preliminarily prove the feasibility of the laser Doppler velocity measurement system. After that, a withstanding voltage test on the system is conducted at the Qingdao Deep Sea Base, and the system obtains a normal signal under a high pressure of 40 MPa. A speed comparison measurement is carried out at the China Institute of Water Resources and Hydropower Research. In a low speed range from 0.01 m/s to 0.2 m/s, comparing with the acoustic Doppler velocity meter, the maximum measurement relative error is –9.43%. In a high speed range from 0.8 m/s to 9.6 m/s, comparing with the nozzle standard flow rate system, the maximum relative measurement error is –1.65%. The prototype system is tested in a shallow sea in Lingshui, Hainan. The sinking speed of the prototype system that sinks together with a crane down to a water depth of 50 m, and the towing speed of the system together with the ship at a depth of 2 m are tested. The test proves that the prototype system works normally in a shallow sea environment.

The sensorless control strategy of UAV rotor motor in full speed range

UAV (Unmanned Aerial Vehicle) has broad application prospects in various fields. In order to meet the needs of stability and efficiency during flight, a surface-mounted permanent magnet synchronous motor is used as its rotor motor, and a position sensorless control technology is used to control the rotor motor with high efficiency and high dynamic response. This paper proposes a position sensorless control strategy in the full speed range for the actual application requirements of UAV. In low speed ange, I/F control strategy with speed-open-loop and current-closed-loop is. In medium and high speed range, a sliding mode observer is adopted to provide estimated rotor position and speed. To achieve smooth switching from I/F control stage to speed closed-loop stage, a switching algorithm is proposed. The feasibility of the proposed hybrid control strategy is verified by simulation results.

Fault Tolerant Sensorless Control Strategy With Multi-States Switching Method for In-Wheel Electric Vehicle

The in-wheel electric vehicle with distributed drive units has better stability and flexibility than traditional centralized drives, but may encounter a higher failure rate due to additional actuators and sensors, especially that the faults of the wheel-side position sensor make motor torque out of control. To overcome this problem, a fault-tolerant control strategy with a multi-states switching method is proposed. The strategy judges the sensor failure by verifying redundant speed information, realizes sensorless control schemes by flux-observer based algorithm in high-speed range and I-F control algorithm in low-speed range with low acoustic noise, and applies adaptive transition process between different control schemes. To pursuit high stability, the signal-to-noise analysis for fault judgment due to sensorless estimation accuracy is discussed. Meanwhile, the principle of I-F resonant oscillations during the transition process is initially deduced in detail, and the conclusion of stability condition is obtained. Finally, the influence of system parameters on resonance performance is analyzed by simulation, and the effectiveness and reliability of the proposed strategy for the risk-controlling process are verified by experiments.

Guided Event Filtering: Synergy Between Intensity Images and Neuromorphic Events for High Performance Imaging.

Many visual and robotics tasks in real-world scenarios rely on robust handling of high speed motion and high dynamic range (HDR) with effectively high spatial resolution and low noise. Such stringent requirements, however, cannot be directly satisfied by a single imager or imaging modality, rather by multi-modal sensors with complementary advantages. In this paper, we address high performance imaging by exploring the synergy between traditional frame-based sensors with high spatial resolution and low sensor noise, and emerging event-based sensors with high speed and high dynamic range. We introduce a novel computational framework, termed Guided Event Filtering (GEF), to process these two streams of input data and output a stream of super-resolved yet noise-reduced events. To generate high quality events, GEF first registers the captured noisy events onto the guidance image plane according to our flow model. it then performs joint image filtering that inherits the mutual structure from both inputs. Lastly, GEF re-distributes the filtered event frame in the space-time volume while preserving the statistical characteristics of the original events. When the guidance images under-perform, GEF incorporates an event self-guiding mechanism that resorts to neighbor events for guidance. We demonstrate the benefits of GEF by applying the output high quality events to existing event-based algorithms across diverse application categories, including high speed object tracking, depth estimation, high frame-rate video synthesis, and super resolution/HDR/color image restoration.

A 2.5MW Wind Turbine TL-EMPC Yaw Strategy Based on Ideal Wind Measurement By LiDAR

This paper analyzes the yaw data of the 2.5MW wind turbine of XEMC Windpower Company, and the real wind information collected by the wind farm, and proposes a two-level economic model predictive control (TL-EMPC) yaw strategy based on ideal wind measurement by light detection and ranging (LiDAR). This strategy comprehensively considers the power loss caused by yaw misalignment and the structural loads of the yaw bearing during the yaw process, making the yaw system more efficient and economical: In the high wind speed range, the yaw system has a higher sensitivity by setting the threshold of the yaw error angle, so as to fully capture wind energy; in the low wind speed range, fully consider the fatigue load of the critical parts of the wind turbine during the yaw process, thus Improve the economy of the wind turbine yaw system. The fatigue load and limit load of the yaw actuator at different yaw speeds are analyzed, and the best yaw speed is obtained. The finite control set of the yaw speed is established, which is used as the constraint set of the second-level minimum objective function. Finally, an external controller was used to simulate the 2.5MW wind turbine model in Bladed, and the effectiveness of the control strategy was verified.

ВЫСОКОПРОИЗВОДИТЕЛЬНЫЙ ИНФОРМАЦИОННО-УПРАВЛЯЮЩИЙ КОМПЛЕКС ДЛЯ ПЕРСПЕКТИВНОГО ВЫСОКОСКОРОСТНОГО ВЕРТОЛЕТА

Relevance Onboard computing systems (OCS) of modern aircraft (AC) have a system-oriented decentralized structural organization. The decentralized principle provides that the OCS is built in the form of a certain set of subsystems, between which the functional distribution of tasks is carried out. In this case, each of the specialized subsystems performs its functional task, exchanging, if necessary, information with other subsystems through the corresponding information transmission channels. However, as the functional tasks become more complex and their number increases, the decentralized principle of building on-board systems has largely exhausted its capabilities. First of all, this concerns such promising developments as the project to create a high-speed helicopter. The implementation of the concept of a promising high-speed helicopter requires the development of a high-performance on-board information and control complex capable of performing various functions in order to ensure high speed and long flight range, as well as the possibility of landing on unprepared sites. Aim of research The aim of research is to increase the performance of the on-board computer complex by forming an open architecture based on combining COST products, planning computing processes and choosing the optimal structural organization of the hardware. The objectives of the research project: 1. creation of a high-performance information and control complex based on open architectures and on the basis of integrated modular avionics; 2. using the optimization method of this complex to select the optimal possible solution to problems for a high-speed promising helicopter. Methods of research Method of generalized ranks is being worked out in detail. Ranking is made according to four criteria: total product volume, product weight, product availability, and product performance evaluation. Results The scientific novelty of this research project lies in solving problems associated with the formalization of procedures for the optimal configuration of the onboard information and control complex, based on the choice of methods for forming a set of acceptable options for onboard equipment that meet the modern concept of modular avionics, and the principles of heuristic optimization of the vector optimization base. The methods proposed in the work make it possible to improve the quality of the tasks assigned to high-speed helicopters by introducing a high-speed on-board information and control complex that meets the optimal requirements for performing the tactical and technical characteristics of a combat vehicle, which uses optimal COTS modules used on the basis of integral modular avionics. The introduction of the results of the research project into the development of promising high-speed helicopters will, according to estimates, increase the performance of the assigned tasks in front of the combat vehicle by 5–10 %.

A Hybrid Method of Rounded Hexagon Flux Direct Torque Control for Traction Motor in Mid-Speed Range

This paper proposes improved segment direct torque control (DTC) for full speed range in high-power urban rail vehicles engaged in frequent starting and braking. In the mid-speed range, based on a detailed harmonic analysis and comparison, a hybrid method of a rounded hexagon flux for DTC is proposed that can reduce the harmonic distortions in current and voltage. In addition, a circular flux is adopted to eliminate torque ripple in the low-speed range and a hexagon flux is adopted in the high-speed range to eliminate switching frequency. A transition control strategy for different speed segments is presented, and a smooth transition can be achieved. Hence, system stability and security are improved. The operation characteristics and design considerations for the proposed method are also introduced. Finally, a simulation model and a prototype of a full speed range system are built. The simulation and experimental results validate the effectiveness and the advantages of the proposed method.

Improving resistance properties of high-speed ships

Sustainable engineering solutions facilitate and/or force the use of energy more efficiently and, thus, reducing the carbon emission to the atmosphere. This study is related to improving resistance properties of ships, especially in the high speed range, in which they consume large amount of fuels. In this investigation, the model of the Kriso Container Ship (KCS) was taken as the basis to be studied and she was hydrodynamically analysed through the commercial software STAR-CCM+. After the successful validation of the results obtained in these computational fluid dynamics (CFD) analyses by those of the experiments of this model published in [1], the simulations carried out on the models equipped with stern flaps and a combination of stern flaps and interceptors for reducing resistance of the models, were performed in the same manner using the same software. Then the results obtained in all analyses were discussed by comparing those with the test ones.

CA single track microstructure simulation of nickel base alloy CM247LC and stainless steel S316L, including experimental validation of S316L

Based on powder-bed fusion, a coupled cellular automata (CA) approach to simulate the microstructure and concentration distribution of two different materials, stainless steel S316 L and nickel base alloy CM247LC, in the middle and high scan speed range is presented. Local non-equilibrium models for rapid solidification are considered in this study and described. The simulation outputs from S316L and CM247LC are qualitatively and quantitatively compared with each other and validated with experiments in case of S316L. The melt pool geometry defines the grain morphology. Thin columnar grains and therefore a larger number can be found in the case of CM247LC compared to S316L. The temperature history, cooling rates and diffusivities have a tremendous impact on the grain morphology, based on SLM microstructure cross-section and single crystal simulations. Furthermore, concentration maps are analysed for both materials. In case of CM247LC, concentration maps are suggested as a possibility to predict hot cracks. Temperature dependent diffusivity coefficients and atomic spacing parameters are suggested. Simulations and experimental results are in good agreement.

Experimental research on tribological characteristics of TiAlN coated valve plate in electro-hydrostatic actuator pumps

Moving towards high power density, high dynamic responsibility, and high reliability, the electro-hydrostatic actuators (EHA) have put forward great demand on the piston pumps. As a typical pump control system, EHA pumps need to maintain high efficiency in a wide range of rotational speed and pressure to implement the function of position servo. High speed and wide speed range bring great challenge to the cylinder block/valve plate interface, which has to fulfill simultaneously a bearing and sealing function. Cermet coatings are beneficial to improve the friction and wear performance of the sliding surfaces. In this study, a dedicated frictional test apparatus of cylinder block/valve plate interface has been built which could accurately simulate the working conditions of EHA pumps in a wide operational condition. Equations of the friction coefficient are established based on the combination of experiments and friction theory. When pairing with the tin-bronze cylinder block, friction coefficients of TiAlN coated and nitrided valve plate are calculated by these equations. Additionally, the wear status of these two friction pairs are evaluated by a 3D measuring laser microscope. In the wide speed range of 500–10000 rpm, the decrease percentage of friction coefficient and the wear rate for TiAlN coated valve plate are 52.55%–64.9% and 12–14% of the nitrided one, respectively.

Review of the Design and Technology Challenges of Zero-Emission, Battery-Driven Fast Marine Vehicles

The paper deals with a critical review of unique problems and challenges related to the design and technology of zero-emission, battery driven, fast marine vehicles. The uniqueness of the ensuing ship design problem is the request to fit maximum battery capacity and to ensure minimum required power in order to achieve the set operational requirements for high service speed and sufficient range. The high-speed requirement is inherently connected with the request for minimum structural and lightship weight, while the design needs also to comply with set regulatory safety constraints. The underlying research is in the frame of the EU funded project TrAM (Transport: Advanced and Modular) and leads to the development and construction of a physical demonstrator for operation in the Stavanger area in Norway. The paper discusses the incurring critical issues, discusses the feasibility of the concept and concludes on the way ahead.

High-speed range and velocity measurement using frequency scanning interferometry with adaptive delay lines [Invited

Range (i.e., absolute distance), displacement, and velocity of a moving target have been measured with a frequency scanning interferometer that incorporates a 100,000scans-1 vertical-cavity surface-emitting laser with 100 nm tuning range. An adaptive delay line in the reference beam, consisting of a chain of switchable exponentially growing optical delays, reduced modulation frequencies to sub-gigahertz levels. Range, displacement, and velocity were determined from the phase of the interference signal; fine alignment and linearization of the scans were achieved from the interferogram of an independent reference interferometer. Sub-nanometer displacement resolution, sub-100-nm range resolution, and velocity resolution of 12µms-1 have been demonstrated over a depth measurement range of 300 mm.

Improved Feature-Position-Based Sensorless Control Scheme for SRM Drives Based on Nonlinear State Observer at Medium and High Speeds

The article proposes a nonlinear state observer (NSO) for robust position-sensorless control of switched reluctance motor (SRM) drives over medium- and high-speed range. A classical reference flux-linkage method is adopted to capture a feature position of the SRM, which avoids the use of 3-D magnetic characteristics and has better universality. However, the estimation accuracy of this method would be deteriorated due to flux-linkage errors. To ease the problem, the NSO is developed to enhance the robustness against flux-linkage distortions for more accurate position and speed estimation. This observer can first reconstruct complete position information from a low-resolution feature position. The adverse impact of flux-linkage errors on position estimation is then investigated through a novel small-signal approximation and suppressed by an augmented state estimator. Afterward, a parameter design scheme is given to ensure the observer's stability and improve the capability in distortion suppression. To baseline the performance, comparative experimental validation between the proposed NSO and a widely used linear prediction method is conducted on a 12/8 SRM setup. The results show that the proposed strategy can improve the overall position-sensorless control performance in both the steady and transient states.

Self-excited vibration of an impeller blade of the waterjet propulsion shaft in a naval vessel caused by flow-induced thrust load

Recently, one of the blades of an impeller installed in the water-jet propulsion shaft of a particular naval vessel was fractured. Macro and microscopic investigation of the fracture surface indicated that the fracture was caused by mechanical fatigue. Therefore, root cause analysis is performed related to the vibration fatigue. Measurement of the accelerations on the thrust bearing housing showed that very high vibration occurred at the high-speed range over 600 rpm, and that the frequency of vibration did not vary according to the variation in rpm. Since dynamic thrust load is applied on the impeller blade, it can be assumed that the dynamic thrust load is represented as a nonlinear function of the ship speed and the rotation speed of the impeller. When the equation of motion of the shaft is derived with this assumption, it can be known that the shaft system can be unstable at certain condition where the self-exciting vibration occurs.In this research, numerical analysis and experiments are conducted to verify the assumption that the root cause of the impeller’s fracture is self-exciting vibration from the increasing flow-induced thrust load of the impeller.

Buried PM inner rotor magnetic gear evaluation

Inner rotor SFPMR glued on the rotor surface with material of high compressive strength but low tensile strength cannot sustain the centrifugal force in the high-speed operation, thus require retaining sleeve. Electrical motor employ the retaining sleeve to increase the rotor strength, but so far in MG, there are limited design that employ this technique. Another method to avoid PM from displaced is by buried into the rotor yoke. However, this method may result in lower torque and noise. In this paper, new MG structure is designed. The inner rotor surface mount PM of magnetic gear is rearrange as buried PM. First, the torque analysis of the MG is simulated without counting any loses. Then, gear efficiency is simulated over high speed range and compared to the original topology to identify the amount of reduction of the torque. The result agrees that the buried rotor reduced the torque output 3 times lower than the surface mount PM and disturb the torque which result in high torque ripple over 240%.

Behavior of the Speed and Temperature of the Solar Wind during Interplanetary Disturbances Creating Forbush Decreases

Forbush decreases of cosmic rays are caused by two types of solar sources: coronal holes and coronal mass ejections. In some cases, the identification of the solar source with the interplanetary disturbance causing the Forbush decrease is difficult and requires a thorough and detailed analysis of the solar-wind characteristics. In these cases, it is useful to compare the behavior of the proton temperature and speed of the solar wind. In this paper, this comparison is carried out based on a large amount of experimental material summarized in the IZMIRAN databases. The dependence of temperature on speed for a quiet solar wind is found to have a power character with a steeper spectrum in the low-speed range (V < 425 km/s; exponent index 3.37 ± 0.02) than in the high-speed range (V ≥ 425 km/s; exponent index 2.21 ± 0.02). Based on the obtained T–V dependence, the expected proton temperature Texp and the temperature index KT = Tobs/Texp (Tobs is the observed temperature) are calculated for every hour with available data on the solar-wind parameters from July 1965 to December 2018. This index is anomalously high in the regions of the interaction different speed solar-wind streams and is anomalously low inside magnetic clouds. This makes it possible to detect the Forbush decreases associated with these interplanetary structures and to identify their solar sources.

Quick and seamless transition method for I‐f to sensorless vector control changeover and on‐the‐fly start of PMSM drives

A smooth changeover from the I-f method to closed-loop sensorless vector control is a critical requirement for permanent magnet synchronous motor (PMSM) drives using a back-emf based sensorless algorithm for medium- to high-speed range control. The existing methods provide a smooth transition by aligning the angle generated by I-f control to the sensorless estimated angle. However, the overall start-up time increases due to the additional transition interval, which limits the usability of these methods for applications requiring a quick start-up. Furthermore, the use of a direct transition method to reduce the changeover time results in speed and current oscillation if the estimated position using sensorless algorithm is having an error. In the proposed method, the inverter pulses are disabled for a short duration and the machine back-emf is measured after the stator current falls to zero. Therefore, a quick and seamless transition is achieved in the proposed method by accurately estimating the rotor position from the sensed back-emf. The proposed method is also extended to perform on-the-fly start for power failure ride through during short time power supply interruption. The performance of the proposed method is verified using simulation and experiment on a 25 kW PMSM drive.