Automation is being developed and implemented in a variety of industries with the goals of improving overall system performance and reducing the probability and impact of human or operator error. ...However, as automation is introduced, it changes the role of the operator and creates new opportunities for different and unanticipated types of errors. In the rail industry, automated safety protection and optimization systems are being introduced into the locomotive cab. This paper describes a simulator-based investigation of human-automation interaction in the locomotive cab. Three scenarios were conducted in a dynamic and realistic rail simulator with three professional locomotive engineers. This preliminary study identified three distinct errors related to failing to appropriately monitor automation, and suggested potential opportunities for design improvements.
Rolling-element bearing vibrations are random cyclostationary. This paper addresses the problem of noise reduction with simultaneous components extraction in vibration signals for faults diagnosis of ...bearing. The observed vibration signal is modeled as a summation of two components contaminated by noise, and each component composes of repetitive transients. To extract the two components simultaneously, an approach by solving an optimization problem is proposed in this paper. The problem adopts convex sparsity-based regularization scheme for decomposition, and non-convex regularization is used to further promote the sparsity but preserving the global convexity. A synthetic example is presented to illustrate the performance of the proposed approach for repetitive feature extraction. The performance and effectiveness of the proposed method are further demonstrated by applying to compound faults and single fault diagnosis of a locomotive bearing. The results show the proposed approach can effectively extract the features of outer and inner race defects.
•An approach for repetitive transients extraction is proposed.•The approach is based on the formulation of a convex optimization problem.•The non-convex penalty function is used to strongly promote sparsity.•A fast iterative algorithm is derived.•Effectiveness is verified via simulation study and engineering data
Harmful influence of human factor upon industrial processes and while vehicles running control necessitates to search for ways of its minimizing or total elimination. During the trials of ergatic ...system "locomotive team - brigade" assessment of informative functioning capacity of machinist is done with experimentally-statistic method. According to the research done the total number of signals that influence on locomotive brigade in process of movement makes approximately 20000 for during one trip, and the number of signals indicating abnormal situation reaches 165 for one trip. In time of train movement the period of signal processing lays at such interval - 0.3c < toc < 11c. It was stated during calculations with given assumptions that informative functioning capacity of a locomotive brigade approaches the threshold values, which constitute 2-4 bps. Received model allows to evaluate parameters of informative functioning capacity on a locomotive brigade in contrast to the information which should be obtained by a machinist in process of taking management decisions. This enables to define the ways of a locomotive brigade informative functioning capacity decrease.
A regenerative braking energy recovery strategy based on pontryagin's minimum principle (PMP) for Fuel Cell (FC)/Supercapacitor (SC) hybrid power locomotive was proposed in this paper. In the ...proposed strategy, the dynamic coefficient λ is used in PMP during the traction state of the locomotive, which makes system transient hydrogen consumption minimum. What's more, during locomotives brake state, according to the known parameters of SCs and operation indicators, an optimized braking speed curve can also be obtained which has maximum brake recovery rate. The results are obtained from RT-LAB platform testify that the proposed strategy is able to maximize SC absorption braking energy, and the energy recovery rate improves and maintains SC state of charge (SoC) in a reasonable and safe range, and decreases brake resistors energy consumption in the braking process.
•A regenerative brake energy recovery strategy was proposed.•PMP EMS makes system transient hydrogen consumption minimum.•An optimized speed curve can be obtained which has maximum brake recovery rate.•The strategy decreases system hydrogen consumption.
•OSWD outperforms the traditional decomposition methods in resolving mode mixing.•With whale optimization algorithm, OSWD can select the optimal thresholds in the different scenarios.•Even in this ...condition that the fault signal contains multi-component modulation and heavy interference, OSWD can accurately extract all desired fault feature through the iteratively separating the oscillatory components from the residual signal.
Since multicomponent modulation and complicated interference simultaneously exist in the vibration signals caused by the bearing compound fault, the fault feature becomes rather weak and is hard to be extracted. Therefore, the diagnosis of bearing compound fault is always considered as the bottle neck issue of machinery condition monitoring. The decomposition methods which can separate the individual component into different modes with appropriate criterion provide an alternative for solving this issue. However, various weaknesses, including mode mixing, depending on predefined mode number and poor noise suppression, seriously restrict their application range. To overcome the disadvantages, a novel decomposition method, swarm decomposition (SWD), is initially introduced in the diagnosis of the machinery fault. Inspired by the swarm intelligence, SWD can intelligently decompose the signal by using the swarm filtering and iterative algorithm. A series of analysis, including an impulse responses test and a numerical validation, verifies SWD has a remarkable performance in the decomposition of multicomponent modulation signal. Yet, the superiority also relies on the choice of thresholds. Therefore, a novel nature-inspired meta-heuristic optimization algorithm, whale optimization algorithm (WOA), is applied to solve the problem. Benefiting from the virtues of SWD and WOA, the proposed optimal swarm decomposition (OSWD) is more suitable for the weak feature extraction from multicomponent modulation signal. Finally, to further highlight its superiority in the diagnosis of the bearing compound fault, a number of simulation and real datasets from the axle box bearings of locomotive are applied. Results show that OSWD can be considered as an alternative to address the bottle neck issue from the bearing compound fault.
Polygonisation is a common nonuniform wear phenomenon occurring in railway vehicle wheels and has a severe impact on the vehicle–track system, ride comfort, and lineside residents. This paper first ...summarizes periodic defects of the wheels, including wheel polygonisation and wheel corrugation, occurring in railways worldwide. Thereafter, the effects of wheel polygonisation on the wheel–rail interaction, noise and vibration, and fatigue failure of the vehicle and track components are reviewed. Based on the different causes, the formation mechanisms of periodic wheel defects are classified into three categories: (1) initial defects of wheels, (2) natural vibration of the vehicle–track system, and (3) thermoelastic instability. In addition, the simulation methods of wheel polygonisation evolution and countermeasures to mitigate wheel polygonisation are presented. Emphasis is given to the characteristics, effects, causes, and solutions of wheel polygonisation in metro vehicles, locomotives, and high-speed trains in China. Finally, the guidance is provided on further understanding the formation mechanisms, monitoring technology, and maintenance criterion of wheel polygonisation.
In recent years the detrimental environmental impacts and concerns of emissions from ever-increasing locomotives have motivated the scientific community to search for alternative fuels based on ...renewable lipids, such as microemulsion based hybrid biofuels (MHBF). Emulsification or hybrid fuel preparation process is one of the simplest among the other biofuel production processes that do not require any chemical reaction or complex chemical handling process. This article specifically reviewed various routes for the preparation of MHBF from renewable lipid (oil) sources. In other words, the exploration of the utility of vegetable oil for MHBF formulation, physicochemical properties, comparison with biodiesel, biodiesel blends and petrodiesel, phase stability and performance analysis of CI engine are the targeted focus of the article. This study has also focused on the effects of various fuel components viz. surfactants, co-surfactants, etc., upon the physicochemical characteristics of MHBF. The microexplosion phenomenon that describes the actual combustion has been illustrated. The stability assurance of MHBF is directly influenced by the hydrophilic-lipophilic balance (HLB) value. The engine performance parameters viz., brake specific fuel consumption, mechanical, volumetric and overall efficiency have been reviewed and found that these values are comparable to the biodiesel blends with petrodiesel and pure petrodiesel. Emissions reported by the various researcher, however, have a positive attribute with respect to SOx, CO and NOx which are always lowest, while using MHBF in comparison to biodiesel and petrodiesel, in contrast to large emissions of thermal NOx in biodiesel. Unburnt hydrocarbon (UHC) is however in the higher side than biodiesel blends and petrodiesel which is manageable with increasing load. It can be ascertained from the review that MHBF can eventually replace the other renewable liquid fuel formulation in due course of time for CI engines in agro-farming machinery or even in heavy-duty vehicles attributed to the simplicity of preparation process.
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•Preparation of microemulsion based hybrid biofuels from lipid and comparative study with biodiesel and petrodiesel.•Effects of surfactants and co-surfactants in the overall properties of MHBF formulation.•Ternary diagram for phase stability of MHBF and dependency on HLB value.•Illustration of microexplosion phenomenon during MHBF combustion.•Studies of engine performance, combustion and emission profiles with different MHBF formulations.
•A multiscale fractional order entropy infogram is proposed for machinery fault diagnosis.•The entropy is calculated over a range of scales to extract fault signatures.•The infogram is extended to ...fractional domain and the optimal fraction order is decided.•The optimal band is selected by multiscale fractional order entropy infogram.
The presence of repetitive transients in vibration signals is a typical symptom of local faults of rotating machinery. Infogram was developed to extract the repetitive transients from vibration signals based on Shannon entropy. Unfortunately, the Shannon entropy is maximized for random processes and unable to quantify the repetitive transients buried in heavy random noise. In addition, the vibration signals always contain multiple intrinsic oscillatory modes due to interaction and coupling effects between machine components. Under this circumstance, high values of Shannon entropy appear in several frequency bands or high value of Shannon entropy doesn’t appear in the optimal frequency band, and the infogram becomes difficult to interpret. Thus, it also becomes difficult to select the optimal frequency band for extracting the repetitive transients from the whole frequency bands. To solve these problems, multiscale fractional order entropy (MSFE) infogram is proposed in this paper. With the help of MSFE infogram, the complexity and nonlinear signatures of the vibration signals can be evaluated by quantifying spectral entropy over a range of scales in fractional domain. Moreover, the similarity tolerance of MSFE infogram is helpful for assessing the regularity of signals. A simulation and two experiments concerning a locomotive bearing and a wind turbine gear are used to validate the MSFE infogram. The results demonstrate that the MSFE infogram is more robust to the heavy noise than infogram and the high value is able to only appear in the optimal frequency band for the repetitive transient extraction.
Efficient foraging depends on decisions that account for the costs and benefits of various activities like movement, perception, and planning. We conducted a virtual foraging experiment set in the ...foothills of the Himalayas to examine how time and energy are expended to forage efficiently, and how foraging changes when constrained to a home range. Two hundred players foraged the human-scale landscape with simulated energy expenditure in search of naturally distributed resources. Results showed that efficient foragers produced periods of locomotion interleaved with perception and planning that approached theoretical expectations for Lévy walks, regardless of the home-range constraint. Despite this constancy, efficient home-range foraging trajectories were less diffusive by virtue of restricting locomotive search and spending more time instead scanning the environment to plan movement and detect far-away resources. Altogether, results demonstrate that humans can forage efficiently by arranging and adjusting Lévy-distributed search activities in response to environmental and task constraints.
The objective of the study is research into psycho-physiological methods of control over the functional status of a person for higher efficiency of a pre-trip control of locomotive crew members. It ...is related to the fact that today's medical methods do not reveal some states which decrease a functional reliability level, particularly, a fatigue level and borderline states. The authors selected parameters which, according to the functional system theory, give information on conditions of two regulation levels in the human body, physiological and higher nervous activity, and correspond to the formulated requirements in terms of the procedure. The study experimentally proved the informative value of 27 psycho-physiological parameters for estimation of exhaustion and borderline states. For a state of exhaustion the hemodynamic parameters, including those of arrhythmia, both sinus and slow waves, were of the most informative value. The study revealed the parameter of arterial pressure pulse, the value of which in the post-trip group decreased by 25%. While identifying existence of borderline states by sinus arrhythmia parameters, it turned out that much more people with borderline states were in the exhaustion zone, rather than in the control group (42% and 16% respectively).
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