Special Vehicle Research Articles

Research progress on transmission performance of special vehicles based on power loss characteristics analysis

The vehicle transmission system is a power transmission device between the engine and the wheel load. As the connecting hub of the power system, the travel system and the braking system, it ensures the mobility and safety of special equipment in combat missions. From the four aspects of the transmission system structure composition characteristics, power transmission characteristics, energy flow characteristics and vehicle power characteristics, it is demonstrated that the transmission efficiency is an important technical indicator for evaluating the performance of the transmission system; based on the analysis of the relationship between power loss and transmission efficiency, a global model framework of the power loss of the transmission system is established from the perspective of the generation mechanism and structural characteristics, providing a theoretical basis for the performance characterization of the transmission system; from the three aspects of theoretical numerical research, simulation research and experimental demonstration research of transmission efficiency, the difficulties and key points of the research on the power loss of the vehicle transmission system are discussed, and it is pointed out that the multi-media and multi-parameter coupling simulation analysis and experimental research of large-scale mechanical equipment under complex operating conditions can provide guidance for the performance optimization and health management of vehicle transmission components, and the performance evaluation and matching design of the transmission system; it is expected that the comprehensive transmission efficiency analysis under multiple factors, as well as the coupling research of power loss characteristics, efficiency characteristics and performance degradation characteristics based on intelligent algorithms have practical engineering significance for the performance monitoring and evaluation of large-scale mechanical equipment.

Design and Implementation of Unity-based Special Unmanned Vehicle Operating Simulator

Special unmanned vehicles can replace personnel to perform military tasks with high risk coefficients, such as long-distance reconnaissance, guided irradiation, and weapons strikes. In order to ensure that the special unmanned vehicle can quickly and accurately complete the established task action, the operator should carry out a large number of trainings in advance for the task content, if the training is directly used in the early stage of the training to manipulate the training, which has the security risks, it’s easy to increase the operator's psychological pressure, and the actual training site can't realistically restore the task scene, the training effect is also single. In view of the above problems, this paper designs a special unmanned vehicle control simulator, which enables the trainers to intuitively understand the task content and key points, and at the same time can control the unmanned vehicle in the virtual task environment to carry out the established task training and result review and analysis, so as to rapidly improve the control level of the trainers and ensure the successful completion of the established task.

Sound quality evaluation in special vehicles based on multiple linear regression

The issue of interior sound quality in specialized vehicles has received widespread attention, which could directly affect the riding comfort of the vehicle. This research primarily focuses on the objective quantification of subjective perception of sound qualitySQ in special vehicles. The noise of special vehicles under different working conditions is measured and analyzed, and psychoacoustic parameters and A-weighted sound pressure levels are calculated. The subjective evaluation of interior sound quality was conducted using the grading scale method. A multiple linear regression model is used to establish the correspondence between subjective perceptions and objective parameters. It provides a reference basis for evaluating the sound quality of special vehicles.

Policy recommendations on supporting employee financial participation

Purpose From the first PEPPER report in 1991 until this PEPPER V Report the EU has not only expanded from 12 Members States to currently 27 but also faced complex and urgent challenges. Both the financial crisis of 2008/09 and the coronavirus disease 2019 (COVID-19) pandemic 2020/21 have left their marks on “Social Europe”. Although the overall dynamic of employee financial participation (EFP) across the EU 27 is positive, EFP is declining in terms of its share of household income in the light of the concentration of capital ownership and of capital income. Along with the issue of distributive justice, other challenges, such as business succession in small and medium enterprises (SMEs) that have been on the agenda for decades, and new ones like the extension of EFP to social enterprises, are calling for action.Design/methodology/approach From the comparison of the countries, the cluster analysis and the background of the importance of legal framework and fiscal incentives, two general principles can be derived: (1) establishing EFP schemes through legislation is of primary importance as countries that provide a stable and transparent regulatory framework for EFP also show a wider implementation of EFP practices; (2) when properly designed, fiscal incentives promote the spread of EFP effectively as both countries with a long tradition of tax incentives for EFP (e.g. UK, France) and those with a more recent development (e.g. Austria) confirm.Findings It is against this background that the following policy recommendations should be read. Tax incentives should (and in most countries they actually do) target those taxes, which constitute the heaviest burden in the national taxation system. (1) Tax incentives should be provided for both employees and the employer company. (2) Even substantial tax incentives may prove inefficient when the pre-conditions for eligibility are too restrictive, complex or inflexible. (3) Some forms of tax incentives are more suitable for certain types of plans, e.g. deferred taxation for employee share ownership (ESO), capital gains tax in lieu of personal income tax for dividends and sale of shares, or tax exemptions for matching contributions for European Employee Stock Ownership Plans (ESOPs).Originality/value In light of this need for SME action and the great potential for introducing ESO in this enterprise segment, from our recommendations we emphasise in particular: Alleviating the evaluation problem in unlisted SMEs through debt-to-equity-swaps. ESO may initially take the form of an employee loan to the company, creating corporate debt, which is subsequently converted into company shares. Facilitating share transfers in privately held limited liability companies (LLCs) by ending the requisite for notarial certification (Italy and France) or limiting it to the identity of seller and buyer. ESO in SMEs via intermediary entities, e.g. trusts, foundations, LLCs or other special purpose vehicle (SPVs) to hold and administer employee shares (AT, IE, UK, HU, FR, SI, USA).

Experimental investigation on the longitudinal stability of the aerodynamically alleviated marine vehicle with multi-steps

To investigate the hydrodynamic performance and motion characteristics of the ultra-high-speed aerodynamically alleviated marine vehicle (AAMV) with multi-steps, a towing tank test scheme was designed and carried out at the China Special Vehicle Research Institute. The study analyzed the effects of canard angle, flap angle, longitudinal center of gravity, and displacement tonnage on the motion stability of multi-stepped AAMV at different speeds. The results indicate that the canard generates an overturning moment that reduces the resistance but brings forward the speed at which porpoising behavior occurs. Additionally, the backward shift of the longitudinal center of gravity causes motion oscillation during the high-speed planing phase, which negatively affects longitudinal stability. On the other hand, the flaps provide aerodynamic lift and restoring moments, improving the lift-drag ratio and enhancing longitudinal stability. Furthermore, while increased mass may result in higher total resistance, it can actually improve resistance performance per unit mass and improve the lift-drag ratio at cruising speed. The computational fluid dynamics (CFD) method was used to analyze the destabilization mechanism of AAMV under extreme conditions in the test. Numerical results indicate that the longitudinal stability of AAMV is directly affected by the relative positions of the center of gravity and the center of pressure. These results demonstrate the changing rules of resistance performance and longitudinal stability of AAMV under different design parameters, thus providing a powerful tool for optimizing AAMV.

Study of the effects of shallow-buried charge parameters on the lower limb injuries of occupant in special vehicle body

In the process of military missions, special vehicles often encounter shallow buried charge threats that will greatly affect the safety of the occupants. To study the integrated effects of shallow buried charge detonation point, height-to-diameter ratio, burial inclination, weight, and other key parameters on the lower limb injuries of occupant, this study was based on the special body of a shallow buried explosive test and numerical calculation methods. The reliability of the numerical model and the load effect mechanism of the shallow burial charge were studied. Based on this, the lower limb injuries response law of occupant was analyzed with respect to each parameter. The results showed that the bottom charge load mainly came from two-stage ejection loading, in which the first stage was a strong load with short-duration local impact loading and the second stage was a weak load with long-duration extended range loading. By comparing the lower limb injury response of occupant under different charge parameters, we found that the weight of charge had the greatest effect on the extent of occupant injury, followed by the height-to-diameter ratio and burial inclination, while the detonation position had a relatively small effect on the injury magnitude. Finally, a comprehensive prediction model of the lower limb injuries of occupant was obtained by using the Latin hypercube sampling method and the least-squares method, and it was verified that the model had a good matching accuracy.

Project finance or corporate finance for renewable energy? an agent-based insight

State-of-the-art macroeconomic agent-based models (ABMs) include an increasing level of detail in the energy sector. However, the possible financing mechanisms of renewable energy are rarely considered. In this study, an investment model for power plants is conceptualized, in which energy investors interact in an imperfect and decentralized market network for credits, deposits and project equity. Agents engage in new power plant investments either through a special purpose vehicle in a project finance (PF) structure or via standard corporate finance (CF). The model portrays the growth of new power generation capacity, taking into account technological differences and investment risks associated with the power market. Different scenarios are contrasted to investigate the influence of PF investments on the transition. Further, the effectiveness of a simple green credit easing (GCE) mechanism is discussed. The results show that varying the composition of the PF and CF strategies significantly influences the transition speed. GCE can recover the pace of the transition, even under drastic reductions in PF. The model serves as a foundational framework for more in-depth policy analysis within larger agent-based integrated assessment models.

Desirability of Sukuk as a New Investment Avenue: An Exploratory Study in Bangladesh

Sukuk can be a worthwhile device for meeting demand of those willing to invest in Shariah-compliant avenues of investment, which has been largely catered by Islamic banking products in Bangladesh. Using survey data collected from existing market investors, this study aims to explore the factors contributing to their choice of investment in sukuk. The risk-return preference of the investors is crucial for structuring the sukuk for issuance. Major factors contributing to the investment decision of the sukuk of surveyed participants also include confirmation of the use of proceed of the project in a Shariah-compliant way, risk-adjusted return, timely payment of the expected cash flows, tradability in the secondary market, awareness regarding the expertise, and independence of the Shariah advisors in the Shariah supervisory board (SSB). To facilitate the new instrument and utilize it for the development of the country, especially for the infrastructural development and green projects, government and other policymakers can contemplate offering government guarantee as well as tax exemptions demanded by the respondents of this study. The respondents expressed aversion to longer-term investment opportunities; rather sukuk maturity of up to five years was found desirable. Apprehension for upholding a distinct special purpose vehicle (SPV) and trustee for sukuk was revealed in the study. Although sufficient care was taken in selecting the sample, the limitation of the study is that it may not be deemed conclusive due to the lower sample size. A larger scale study may be conducted to reckon the insight of more potential investors in the market.

Experimental assessment of strength characteristics of anthropogenic soils in a given mining area for justification of tractor propulsion type

BACKGROUND: In mining, there is a need to develop tractors as special robotic vehicles of the robotic mining facility that can efficiently move and work on soils with low bearing capacity, in waterlogged areas and in the underwater position. A preliminary evaluation of the strength characteristics of such a heterogeneous surface of the exploitation area helps to choose an effective concept and technical characteristics of the propulsor of the tractor. AIM: Formation of the database of the physical condition and mechanical properties of the environment in which the tractor will move and operate. METHODS: In order to achieve the aim, preliminary experiments were conducted on the terrain. Typical kinds of soil sites and watered areas, including those of anthropogenic origin, of a given mining area were identified. Full-scale instrumental tests were conducted to determine: granulometric composition of soils; physical and mechanical parameters of these soils at the selected sites using the developed original types of a penetrometer and a shear rig. RESULTS: The database of numerical values of measured strength characteristics of one of the soil types (as an example) as a possible supporting surface for vehicle motion in the area of mining facility operation is presented in a graphical form. The basis of this database is the graphs according to the results of experiments on free settlement and shear with the help of dies of two types of configuration (the round die and the original caterpillar track respectively); the granulometric composition of the selected soils has been evaluated. CONCLUSION: The methodology of preliminary assessment of the soil condition by two indicators of soil strength (the rut depth z depending on the average pressure under the die) and shear (average tangential stresses τ in the contact patch on the motion of the die relative to the soil, depending on the ratio of the normal force and the traction force in the contact plane) has been developed. The 3D model of the coastal and bottom area of the technogenic mining zone has been developed. Design variants of highly efficient types of tractor propulsors are selected on the basis of prediction of maximum allowable stresses in the contact patch with the ground for the bearing surface areas of the considered area of operation.

Integrated Dynamic Modeling and Simulation of Wheeled Vehicle with Outer-Rotor In-Wheel Motors and Key Units

The purpose of this paper is to accurately establish a model of a special vehicle driven by in-wheel motors (IWMs) and investigate its dynamic characteristics. This study proposes a novel integrated vehicle modeling strategy, focusing on the IWM and other key subsystems. Based on this strategy, the vehicle model is developed and simulated in ADAMS. The natural frequencies of the vehicle and transmission characteristics of key components are compared with MATLAB simulation results to validate the accuracy of the model. In the time-domain analysis, the vehicle system’s time-domain characteristics are obtained by using random road spectra of different road grades as excitations. Our simulation results demonstrate that vibration input can be reduced by between 97% and 99% after multi-stage vibration reduction. This work will provide relevant parameters for the design of special vehicles driven by IWMs.

A performance-based mental workload identification method for special vehicle crews

Detecting the mental workload state of armored vehicle crews is of great significance for monitoring the driving state of the crew and improving comprehensive combat effectiveness. In this manuscript, we propose a performance-based mental workload identification method and carry out experimental validation to improve the accuracy of crew mental workload identification and realize the effective classification of mental workload. Based on the virtual simulation system of the special vehicle crew task, this manuscript selects 20 subjects for the mental workload experiment of special vehicle crews. The experiment collected NASA-TLX scale, EEG, eye-tracking data, and performance data. The results show that the mental workload of the crews fluctuates in the segmented tasks of complex operations in typical scenes of special vehicles. The method of determining mental workload using NASA-TLX generates label noise in classification, which is not suitable for special vehicle tasks. Performance-based mental workload identification method is able to recognize fluctuations in the crew's mental workload during segmented tasks. Performance-based and NASA-TXL-based methods were classified using linear discriminant analysis. The results show that the accuracy of the method based on performance is improved by 15.72 %. This manuscript found the NASA-TXL scale is not suitable for the complex tasks of special vehicles, and proposed a performance-based identification method that can help to categorize the mental workload states of special vehicle crews.

How to reduce the influence of special vehicles on traffic flow? A Dogit‐ABM approach

How to reduce the influence of special vehicles on traffic flow? A Dogit‐ABM approach

The Deterrence Effects of Tax Whistleblower Laws: Evidence from New York’s False Claims Acts

In this study, we provide evidence on the effects of state tax whistleblower laws. We exploit a novel 2010 amendment to New York’s False Claims Acts (FCA) that explicitly extended whistleblower incentives to corporate income tax whistleblowers. We identify treated firms (firms exposed to New York’s FCA) using establishment-level data and descriptive analyses. Using a sample of firms exposed to New York and neighboring states, we find evidence that New York’s FCA reduced state tax avoidance. In cross-sectional tests, we find that effects are increasing in firms that grant fewer employee stock options and industry regulation, consistent with deterrence increasing in employee and regulator monitoring. We also find evidence that New York’s FCA deterred federal tax avoidance, consistent with positive vertical tax externalities. Next, we focus on particular tax strategies and find evidence of a reduced probability of Double Irish tax structures, reduced relationships to tax planning banks, reduced use of special purpose vehicles, and reduced outbound tax-motivated income shifting. We also find evidence that firms with the lowest (highest) cost of relocation (1) reduced (did not change) establishment counts in New York but (2) did not change (reduced) state tax avoidance. Finally, we disentangle general ex ante deterrence from ex ante peer deterrence using hand-collected New York tax whistleblower press releases from the Attorney General. We find evidence of both types of deterrence. Overall, this study provides policy-relevant evidence on the deterrence effects of tax whistleblower laws. This paper was accepted by Suraj Srinivasan, accounting. Funding: Y. Lee acknowledges financial support from the College of Business at California State University, Long Beach. S. Ng acknowledges financial support from Singapore Management University. T. Shevlin acknowledges financial support from the University of California, Irvine [the Paul Merage Chair and the Merage School of Business]. A. Venkat acknowledges financial support from the McCombs School of Business at the University of Texas, Austin. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2023.02999 .

Two-stage heuristic algorithm with pseudo node-based model for electric vehicle routing problem

Electric vehicle routing problem (EVRP) is a special vehicle routing problem, which owns several specific characteristics of EV technology including the limited charging stations and the limited cruising range of EVs. This paper proposes a two-stage heuristic algorithm for EVRP with a kind of pseudo node, termed EVRPPN-TSH, which not only contributes to the model innovation but also to the algorithm design. In model innovation, the pseudo node is introduced into the EVRP model, forming EVRPPN, to reduce the search space and time complexity for obtaining service orders of customers from O(n) to O(1). Moreover, different from other research works which only use total distance as the fitness function, an improved fitness function is proposed, which takes all the distance, the electricity and capacity constraints compliance into consideration. In algorithm design, we first adopt the two-stage idea, which divides EVRP into the capacitated vehicle routing problem (CVRP) and a fixed route vehicle charging problem (FRVCP). Then we design a two-stage heuristic algorithm, termed as TSH. Specifically, for CVRP, a route division heuristic algorithm and a depot move heuristic algorithm are designed to divide routes. Further, an adjustment strategy with three operators is designed for adjusting the customer order. For FRVCP, an existing heuristic algorithm is adopted and enhanced by a variable extent shaking algorithm to avoid local trapped. Experimental results show that EVRPPN-TSH generally outperforms other state-of-the-art algorithms. Moreover, EVRPPN-TSH can obtain the best-known solution in all the 7 test cases, and update the best-known solution in test case E101 from 834.84 to 834.22.

Fault Diagnosis Method of Special Vehicle Bearing Based on Multi-Scale Feature Fusion and Transfer Adversarial Learning.

To address the issues of inadequate feature extraction for rolling bearings, inaccurate fault diagnosis, and overfitting in complex operating conditions, this paper proposes a rolling bearing diagnosis method based on multi-scale feature fusion and transfer adversarial learning. Firstly, a multi-scale convolutional fusion layer is designed to effectively extract fault features from the original vibration signals at multiple time scales. Through a feature encoding fusion module based on the multi-head attention mechanism, feature fusion extraction is performed, which can model long-distance contextual information and significantly improve diagnostic accuracy and anti-noise capability. Secondly, based on the domain adaptation (DA) cross-domain feature adversarial learning strategy of transfer learning methods, the extraction of optimal domain-invariant features is achieved by reducing the gap in data distribution between the target domain and the source domain, addressing the call for research on fault diagnosis across operating conditions, equipment, and virtual-real migrations. Finally, experiments were conducted to verify and optimize the effectiveness of the feature extraction and fusion network. A public bearing dataset was used as the source domain data, and special vehicle bearing data were selected as the target domain data for comparative experiments on the effect of network transfer learning. The experimental results demonstrate that the proposed method exhibits an exceptional performance in cross-domain and variable load environments. In multiple bearing cross-domain transfer learning tasks, the method achieves an average migration fault diagnosis accuracy rate of up to 98.65%. When compared with existing methods, the proposed method significantly enhances the ability of data feature extraction, thereby achieving a more robust diagnostic performance.

Research on the evaluation of occupants' work efficiency in summer thermal environment of special vehicles based on subjective thermal sensation

High summer temperatures in special vehicle cabins affect drivers and occupants, reducing efficiency and combat potential. Improving occupant work efficiency is key to enhancing overall combat effectiveness. There's a lack of research on the work efficiency of special vehicle occupants engaged in complex, specialized tasks within cabin thermal environments. This study focused on a special vehicle, discussing the effects of the summer thermal environment in the cabin on personnel efficiency. It linked subjective thermal sensations to work efficiency through questionnaires and task performance evaluations. The best work efficiency environment may not be the environment with the highest thermal comfort. This paper presented a subjective thermal sensation range criterion for maintaining the work efficiency of the occupants in the cabin during the summer. This serves as a basis for optimizing the summer thermal environment and improving the reliability of human-vehicle systems in special vehicle cabins.

Research on an Adaptive Active Suspension Leveling Control Method for Special Vehicles

Adaptive active suspension systems, integral to specialized vehicles, hold significance for their stability and safety. This study introduces a novel adaptive active suspension system featuring four independently controlled wheels employing wheel-hub motors, hydraulic cylinders, pump motor power, controllers, and sensors. A rapid and, within a certain range, leveling and height adjustment control strategy is proposed for this system, utilizing the Kalman filter algorithm. Additionally, the paper examines the front-wheel Ackermann steering model and four-wheel reverse Ackermann transition model to enhance the suspension’s stability. Subsequently, experiments on leveling and height adjustment are conducted, demonstrating the system’s capability to swiftly and accurately rectify the vehicle’s deviation angle within the specified threshold. Following adjustments made by the leveling and height control algorithm, the vehicle body promptly returns to the preset level state and designated height. The leveling control system holds broad applicability in intelligent agriculture, logistics handling, off-road equipment, and other domains, presenting significant practical utility.

THE AIRCRAFT ENGINE PROPELLER MAIN CHARACTERISTICS DETERMINATION IMPROVED METHOD

An improved method of the fixed and variable pitch propeller aerodynamic characteristics determining that based on the vortex theory is presented. It is shown that the design of propellers has it`s peculiarities, it does not take into account a number of factors that affect the propeller operation to one or another degree. This actualized the special purpose unmanned aerial vehicles engines propellers aerodynamic characteristics calculating methodology improvement. Since the use of the propeller profiles performances in the design requires the air compressibility correction introduction already after the selection of the propeller, that complicates the design, therefore the mathematical model of the variable-pitch propeller working process has been improved based on the profile model with the correct consideration of the Mach and Reynolds numbers influence on the aerodynamic characteristics of the air screw. This advantage of the developed airfoil model allows the design and verification of a subsonic propeller for ground and flight operations. Methods of design and verification calculations of propeller blades are presented. Verification of the improved methodology was carried out by comparing calculated data with known experimental data. The reliability of the improved aircraft engine propeller main performances determination methodology is substantiated by the correct application of the numerical and experimental methods of aerodynamics, the consistency of theoretical provisions with experimental data. The satisfactory coincidence of the calculated data obtained by the improved method of the engine propeller main performances determination allowed us to draw a conclusion concerning its efficiency. The improved technique for the main performances of an aircraft engine propeller determination does not require knowledge on the propeller profiles aerodynamic characteristics from which the blade is drawn, since these characteristics are calculated based on known geometric data, taking into account the Mach and Reynolds numbers. This allows you to design and build a subsonic propeller of both fixed pitch and variable pitch.

Modifying Injection Equipment Components for Their Adaptation to Work with Greener Hydrogen-Containing Fuels for Non-Road Vehicle Engines

This article presents the authors’ considerations regarding the possibilities of developing fuel equipment for modern compression ignition engines used in special and non-road vehicles. The paper discusses the process of fuel combustion and atomization in the chamber of a piston combustion engine. The paper then presents the concept of modifying the atomizer of a modern fuel injector for operation using hydrogen-containing fuels of plant origin. The authors present a review of tests performed using an engine dynamometer on a modern engine with a Common Rail system running on biofuel. The CI engine operated with standard and modified fuel injectors. During the tests, the external ecological characteristics of the engine were analyzed as a function of rotational speed; the values of injection doses at individual rotational speeds and their effects on the characteristics were read from the current parameters, and the pressure and temperature in the engine’s combustion chamber were measured. The research results show that implementing the changes proposed by the authors of this work is a good direction for the development of compression ignition engines.

A Novel Double Closed Loop Control of Temperature and Rotational Speed for Integrated Multi-Parameter Hydro-Viscous Speed Control System (HSCS)

Hydro-viscous clutch has already become an inevitable choice for special vehicle transmission in the present and future. As a nonlinear system with a large hysteresis loop, its speed control performance is affected by input rotational speed, lubricating oil temperature, lubrication pressure, and other factors. The traditional control method cannot adjust the temperature and rotational speed, which will lead to problems of narrow speed range, poor rotational speed stability, and large dynamic load impact. In order to solve the above problems, this paper studies the control method of an integrated multi-parameter hydro-viscous speed control system (HSCS) in a controlled environment. Through the mechanism analysis of the law of HSCS, the influence law of speed and temperature during the system operation is found. The temperature closed loop based on model predictive control (MPC) is introduced to control the rotational speed, and then the traditional PID control results are compensated according to the speed closed loop. Next, a novel double closed loop control method of temperature and rotational speed for HSCS is formed. Finally, the simulating verification is carried out. Compared with the traditional control method, the design method in this paper can adjust the control parameters according to the temperature of the lubricating oil and the input rotational speed and effectively expand the domain of HSCS and the speed control stability. The effective transmission ratio is extended to 0.2~0.8, and the hydro-viscous torque and speed fluctuation under the engine rotational speed fluctuation are reduced by more than 30%. The novel control method of HSCS designed in this paper can effectively improve the influence of input rotational speed and lubricating oil temperature on the speed control performance of HSCS and can be widely used in nonlinear HSCS such as hydro-viscous clutch.