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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>The Energy Consumption Characteristics of Electric Vehicles in the Coastal Area Based on the Powertrain</title>
      <link>https://trid.trb.org/View/2325799</link>
      <description><![CDATA[The sensitivity of the electric vehicle (EV) energy consumption characteristics has seriously hindered the promotion and development of vehicle electrification in the coastal area, as quantities of additional energy are caused by the complex and ever-changing coastal driving conditions. In that case, this paper aims to clarify the quantitative impacts of coastal driving conditions on EV energy consumption characteristics based on the coastal traffic data and the EV powertrain. Firstly, this paper analyzes the coastal driving conditions with the help of multisource traffic data. Secondly, the costal-adapted EV energy consumption model is constructed to reveal the relationship between powertrain performance and coastal driving conditions. Next, the EV coastal driving framework is proposed to identify the EV driving state in the coastal area. Finally, the EV energy consumption spatiotemporal characteristics in a typical coastal road are discussed with the help of simulations. The results show that coastal driving conditions have great impacts on the EV energy consumption characteristics, where the temporal difference of EV energy consumption in coastal areas is as high as 19.4%, causing a 19.1% difference in the SOC, and the EV spatial energy consumption characteristics are deteriorated by the high road slope and reversed wind direction once the EV velocity and acceleration are relatively large.]]></description>
      <pubDate>Mon, 29 Jan 2024 09:15:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325799</guid>
    </item>
    <item>
      <title>Improved Prandini Conflict Detection Algorithm Based on Trajectory Prediction</title>
      <link>https://trid.trb.org/View/2325798</link>
      <description><![CDATA[As a traditional probabilistic mid-term conflict detection algorithm, the Prandini algorithm plays an essential role in ensuring flight safety in the aircraft route area. For the issue of mutation error in the calculation results of the Prandini algorithm, this research provides an improved Prandini conflict detection algorithm. First, the integral of the standard Gaussian distribution is solved using randomization. The minimum prediction interval moment is then calculated, and the critical time points at which conflicts may exist before and after that moment are approximated separately using a bisection method. N moment values are selected uniformly within the time range formed by the two critical time points. The instantaneous conflict probabilities for these N moments are calculated and the maximum value is selected from them as a measure of the likelihood of conflict between the two aircraft over the entire route for an extreme case. Finally, a trajectory position prediction error model is built using actual ADS-B data to verify the performance of this improved algorithm for application in the no route change scenario and the multi-route scenario. The experimental results show that compared with the original Prandini algorithm, the method improves the stability of conflict detection and can meet the requirements of air traffic control (ATC) for medium-term conflict detection.]]></description>
      <pubDate>Mon, 29 Jan 2024 09:15:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325798</guid>
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    <item>
      <title>Overview and Research on Airworthiness and Safety of Electrical Propulsion and Battery Technologies in eVTOL</title>
      <link>https://trid.trb.org/View/2325783</link>
      <description><![CDATA[This overview and study article scrutinizes the evolution and challenges of electric vertical takeoff and landing aircraft (eVTOL), with a primary focus on airworthiness and safety certification. The paper discusses key issues such as high-energy-density aviation-grade batteries and the light weighting of electrical propulsion systems. Utilizing scientific models and real-world data, the study outlines the required battery technology and electrical propulsion specifications for eVTOLs with effective commercial load capabilities. For eVTOLs operating in the 300 km range, aviation-grade batteries must achieve energy densities between 300-600 wh/kg. For those covering a 600 km range, the energy density requirements exceed 600 wh/kg. Compliance with stringent safety standards, including triple certification by the FAA under 14 CFR Part 23, is imperative. This article conducted research and offered flowchart of the complicated FAA standard, which is rare in existing articles. This article also proposed better platform which is more conducive to testing the propulsion and battery systems as well as the overall design of electric aircraft, especially eVTOLs. By establishing this more advanced platform, the authors aim to engage industrial partners both in China and internationally in various aspects such as propulsion technology, battery and material technology, and the overall design, manufacturing, and operation of eVTOL to meet airworthiness and safety requirements.]]></description>
      <pubDate>Mon, 29 Jan 2024 09:15:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325783</guid>
    </item>
    <item>
      <title>Research on Vibration Control and Energy Study of Vehicle Electromagnetic Suspension Based on Sliding Mode Control</title>
      <link>https://trid.trb.org/View/2325781</link>
      <description><![CDATA[This article proposes an electromagnetic damper (EMD) based on a ball screw mechanical structure actuator. To prove the damping effect of the new damper proposed in this paper. In this paper, the EMD suspension is validated on a quarter vehicle suspension. A mathematical model of quarter vehicle suspension is developed and a sliding mode variable structure controller is designed. This sliding mode controller enables vibration control of the suspension and improves ride comfort. To make the EMD track the ideal current effectively, a variable resistance circuit that can change the electromagnetic damping force is proposed to achieve the graded adjustment of resistance. A semi-active vehicle vibration control strategy was designed, and experiments were conducted using a quarter-vehicle test platform to verify the vibration-damping performance of this EMD suspension. The energy transfer to the road was analyzed and the higher the variable resistance, the more energy is transferred to the vehicle. The experimental results show that the EMD suspension reduces the acceleration RMS by 25.53 %, 23.57 % and 16.48 % under sinusoidal, bump and random road conditions, respectively, compared to the passive suspension. This ensures that the dynamic travel of the suspension and the dynamic loading of the tire is within reasonable limits. The energy of the road surface, the energy consumed by the EMD, the energy transferred to the tire and the energy of the vehicle were also analysed. The experimental results show that the lower the resistance in the EMD circuit, the less energy is transferred to the vehicle, and that the EMD suspension reduces the energy transferred from the road surface to the vehicle by 8 % compared to the passive suspension under random road conditions. The experiment proves that it greatly improves the comfort of the vehicle while ensuring the stability of vehicle control.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325781</guid>
    </item>
    <item>
      <title>Energy and Power System Design and Test Verification for Electric VTOL</title>
      <link>https://trid.trb.org/View/2325777</link>
      <description><![CDATA[Electric technology has gradually changed the form of energy use in transportation. Electric vertical take-off and landing aircraft (eVTOL) will become an important means of transportation in the future, bringing significant changes to urban transportation and providing a more convenient and comfortable travel experience for people. eVTOLs are being extensively researched and developed by the global aviation industry as well as by many innovative technology companies. In this paper, we focus on the system design and testing of the four-axis and eight-propeller eVTOL. The overall parameters of the aircraft are defined, and the energy and power architecture design and analysis are carried out. Carry out the hybrid power supply design of lithium battery and fuel cell, and complete the parameter matching design of power system. The lithium battery and fuel cell hybrid power supply, single propeller test, dual propeller test, system integration verification were carried out, and finally the bench test was carried out to verify the feasibility of the scheme.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325777</guid>
    </item>
    <item>
      <title>Adaptive Robust Tracking Control for Underactuated Quadrotor Unmanned Aerial Vehicle with Prescribed Performance</title>
      <link>https://trid.trb.org/View/2325775</link>
      <description><![CDATA[Quadrotor unmanned aerial vehicle (Q-UAV) is an underactuated system, which is often used in complex environments, such as maintenance tasks in pipelines. However, flying in pipelines will lead to strong ground effect, implying that the Q-UAV will face time-varying uncertainties. Since the flight space is limited, it needs to achieve agile and high-security flight to avoid collisions. This research proposes an adaptive robust tracking control method to ensure that the Q-UAV can complete the agile and high-security flight missions. Agile and high-security flight is guaranteed by achieving prescribed transient and steady-state performance (PTSSP). Our approach takes into account (potentially rapid) time-varying uncertainties with unknown bounds. We formulate the desired flight altitude and attitude trajectories as equality constraints and the PTSSP as inequality constraints, and use state transformation approach to transform the inequality constraints into equality constraints. Simulation results showcase the superior performance of the proposed control method. This study represents endeavor to accomplish agile and high-security flight of Q-UAV while considering (potentially rapid) time-varying uncertainties stemming from complex environments.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325775</guid>
    </item>
    <item>
      <title>EVTOL Flight Control System Safety: An Example of Application Using MBSA</title>
      <link>https://trid.trb.org/View/2325774</link>
      <description><![CDATA[Electrical Vertical Takeoff and Landing (eVTOL) vehicles hold great promises for revolutionizing urban mobility. Their emergences as a transformative transportation technology has led multiple Original Equipment Manufacturers (OEM) competing for market share, with important variety of technical solutions, all necessitating to demonstrate the compliance to safety requirements and regulations. Model Based Safety Analysis (MBSA), newly introduced in ARP4761A and based on compositional and modular representation of failure propagation paths within one system, provides a unique opportunity to increase efficiency by maximizing the possible reuse of safety analyses elements across multiple architectures (“product line” philosophy). Generic library of safety models for elements of variant architectures can be efficiently constructed using MBSA techniques that can then support safety analyses on variant architectures or architectures trade-off. This approach can facilitate a safety process that enable customized safety solutions without complete re-engineering of the safety analyses for each architecture.The purpose of this paper is to present and illustrate one work performed on the definition of a safe Flight Control System for eVTOL, leveraging the capacity of a MBSA based approach to ensure high level of agility and rapid responsiveness. The first sections will present the need, the MBSA approach and a general modelling process that can be used to employ MBSA methodology. Then, an example of eVTOL Flight Control System architecture and safety analyses will be detailed to picture how MBSA, coupled with a generic component library, can provide an easily adaptable safety solution. Finally, we discuss some possible next steps and future work identified in order to certify a solution thanks to this method.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325774</guid>
    </item>
    <item>
      <title>Wide-Range High-Confidence Surge Margin Estimation Method for Aircraft Engine</title>
      <link>https://trid.trb.org/View/2325769</link>
      <description><![CDATA[The confidence of the onboard adaptive model in estimating surge margin significantly affects the operating stability in an aircraft engine’s active surge margin control process. Unfortunately, the existing onboard adaptive models lack high confidence, although wide-ranging in estimation, due to the unknown surge boundaries in component characteristics. Therefore, this paper first accurately estimates the actual surge margin during the engine operating near-surge boundary using a pressure correlation measurement technology. Then, innovatively, the estimated surge margin is used to correct the surge boundary of the nonlinear onboard model of the engine to obtain the actual surge boundary, thereby guaranteeing confidence. Finally, a nonlinear onboard adaptive model based on an improved spherical unscented Kalman filter is employed to achieve wide-range high-confidence surge margin estimation throughout the engine’s life cycle. Simulation results demonstrate that the proposed method is effective and has a high-confidence level in surge margin estimation, ensuring estimation accuracy of over 95% for both standard and degraded engines, far surpassing existing techniques. The proposed method provides a technical means for sensing surge margin in future high-stability engine active control.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325769</guid>
    </item>
    <item>
      <title>A Wind Tunnel Investigation on the Aerodynamics of the Propulsion Wing for a Novel eVTOL Vehicle</title>
      <link>https://trid.trb.org/View/2325768</link>
      <description><![CDATA[With increasing interest in the urban air traffic market for electric Vertical Take-Off and Landing (eVTOL) vehicles, there are opportunities to enhance flight performance through new technologies and control methods. One such concept is the propulsion wing, which incorporates a cross-flow fan (CFF) at the wing's trailing edge to drive the vehicle's flight. This article presents a wind tunnel experiment aimed at analyzing the aerodynamic characteristics of the propulsive wing for the novel eVTOL vehicle. The experiment encompasses variations in angels of attack, free stream velocities and fan rotational speeds. The result verifies that cross-flow fans offer unique flow control capabilities, achieving a tested maximum lift coefficient exceeding 7.6. Since flow from the suction surface is ingested into the CFF, the flow separation at large angle of attack (up to 40°) is effectively eliminated. The aerodynamic performance of the propulsive wing depends on the advance ratio and angle of attack. Generally, with a high advance ratio and sufficient CFF power for flow control, the airfoil's lift coefficient increases with angle of attack, while drag coefficient decreases with higher fan rotational speeds. Additionally, this study identifies improved flow control capability with the presence of a vortex cavity. The propulsion wing shows promising application prospects for eVTOL vehicle.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325768</guid>
    </item>
    <item>
      <title>Design and Evaluation of Electric Propulsion System for Electric VTOL</title>
      <link>https://trid.trb.org/View/2325760</link>
      <description><![CDATA[Electric vertical take-off and landing aircraft (eVTOL) has become a main trend in general aviation. Battery, power electronic and motor have made big progress in the last decades, most companies and research institutions are focusing on the development of 2-5 seat (2 tons maximum takeoff weight) eVTOL products and strat to put into market. This paper tried to defines the design and analysis process of electric propulsion system taking 2-ton eVTOL as an example. Firstly, the parameters of the aircraft is defined and the power and energy consumption was analyzed based on flight phase. Secondly, the electric propulsion system architecture is defined based on the aircraft design. The design and evaluation of propeller, motor, motor controller and battery were carried out respectively. The optimal design of propeller in hover stage and cruise stage is conducted. Based on the existing products, the selection of the motor and motor controller are conducted, and the matching design with the propeller is analyzed. According to the power and energy requirements of the aircraft, the tradeoff of battery energy density and discharge rate is performed. Finally, the power and energy consumption are re-checked for flight phase. Based on the evaluation in this paper, it is concluded that the current technical status of battery and electric propulsion system can meet the target of 200km range.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325760</guid>
    </item>
    <item>
      <title>Research on Gear Vibration Evaluation Approach of E-Drive System Based on Order Analysis</title>
      <link>https://trid.trb.org/View/2325759</link>
      <description><![CDATA[Gear vibration and noise evaluation approaches are commonly proposed with a variety of way in a transmission system while complicated and obscured, it is difficult to provide a feasible basis for the gear development of E-drive system. Based on the vibration mechanism of E-drive gear meshing and order tracking theory on rotating machinery, this paper expressed the details of gear vibration evaluation approach accordingly during E-drive system’s development phase, combined with objective testing and subjective evaluation correlation analysis, raised the meshing gear order vibration evaluation approach by the means of the testing data target curve-fitting, also verify the reasonableness and validity of this approach on a HEV matched with E-drive system by means of subjective evaluation and objective measurement before and after the gears’ optimization, the clarification shows that significant correlation between subjective evaluation and objective measurement of the meshing gears both of the 23rd and 46th order, It’s been further proved that this approach is reasonable, effective and feasible for the vibration measurement and evaluation of the meshing gears of the E-Motor transmission system. Meanwhile, it also can be used as a reference for the development and diagnosis of powertrain and vehicle.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325759</guid>
    </item>
    <item>
      <title>Study on the Current Status and Evaluation Methods of Noise Certification for Unmanned Aerial Vehicles (UAVs)</title>
      <link>https://trid.trb.org/View/2325757</link>
      <description><![CDATA[This paper tracks the latest development of UAV noise certification regulations in various countries, outlines the current airworthiness noise requirements, focuses on the overview of various UAV noise assessment methods, and analyses the characteristics and differences of the existing UAV noise evaluation methods in terms of evaluation indicators, measurement procedures and data correction. Combined with the existing domestic environmental protection requirements and noise pollution prevention requirements, as well as the requirements of the UAV superseding law, it can be expected that the impact of UAV noise on people will be an important part of the future UAV airworthiness certification, which will be an important guiding significance for states’ legislation and standardization]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325757</guid>
    </item>
    <item>
      <title>Aeroengine Gas Path Parameter Trend Prediction Based on LSTM</title>
      <link>https://trid.trb.org/View/2325754</link>
      <description><![CDATA[Accurately predicting the trend of aero-engine gas path parameters is crucial for ensuring safe flight and enabling condition-based maintenance. However, the demanding and uncertain service environment introduces challenges in dealing with the noisy and non-stationary data collected by engine gas path sensors. Traditional time series models struggle to accurately predicts parameter trends, resulting in insufficient fitting and prediction accuracy. In this paper, the authors address these challenges by leveraging the characteristics of engine post-flight data and introducing Long Short-Term Memory (LSTM), a type of artificial neural network in deep learning. We construct both single-feature input and multi-feature input LSTM prediction models for six key indicators of engine gas path performance.The authors analyze the models' capabilities for single-step and multistep predictions. To evaluate the effectiveness of their approach, the authors compare the LSTM model with the traditional Autoregressive Moving Average (ARMA) model and support vector regression (SVR) method. The results demonstrate that the LSTM model outperforms the traditional ARMA and SVR models in terms of prediction accuracy and stability. This indicates that utilizing LSTM is an effective approach for improving the accuracy of engine gas path parameter prediction. By accurately predicting these parameters, the author can enhance flight safety and enable more efficient condition based maintenance.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325754</guid>
    </item>
    <item>
      <title>Research on Energy Management of Micro-Gas Turbine Range Extended Electric Vehicle Based on Battery Life Prediction</title>
      <link>https://trid.trb.org/View/2325752</link>
      <description><![CDATA[In this work, in order to reduce the overall cost of the micro-gas turbine range extended electric vehicle (MGT-REEV), the energy management strategies of the micro gas turbine range extender were discussed. The overall vehicle cost includes equivalent fuel cost and battery loss cost. The authors defined a cost function to qualify the overall vehicle cost and three rule-based energy management strategies were built and compared. The REEV model was built based on the Cruise platform, energy management strategies were built based on Matlab. The authors discussed thermostat strategy, the constant speed multi-point strategy and optimal curve multi-point strategy under Worldwide Harmonized Light Vehicles Test Cycle (WLTC). The results showed that the constant multi-point strategy had a better effect on reducing the vehicle overall result compared with the other two control. Finally, the multi-objective genetic algorithm based on Isight software was used to optimize the selection of multiple operating points to optimize the vehicle overall cost. The optimized constant speed energy management strategy reduced the overall cost by 6.08% compared to the thermostat strategy. In brief, through the above comparisons and optimization, the influences of different energy management strategies on fuel consumption and battery loss were revealed, which provides a good reference for engineering applications.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325752</guid>
    </item>
    <item>
      <title>Research on Switchable Energy-Regenerative Suspension System</title>
      <link>https://trid.trb.org/View/2325750</link>
      <description><![CDATA[Electromagnetic energy-regenerative suspension can convert the kinetic energy generated by the suspension vibration into electrical energy for energy recovery. However, most research has focused on achieving maximum energy-regenerative efficiency without simultaneously considering the suspension’s damping control, leading to suboptimal vibration damping performance. This paper proposes a novel switchable energy-regenerative suspension (SERS) system, which includes an electromagnetic damper (EMD) and a switchable circuit. First, a detailed description of the mechanical structure and the switchable circuit structure of SRES, and their working principles, is provided. Within the switchable circuit, a double-throw switch is used to connect the damping control module and the energy recovery module. Based on this, the system can switch between these two modules, balancing both vibration damping performance and energy recovery functionalities. Then, corresponding dynamic model is developed. In the damping control model, adjusting the resistance value of the load resistor can alter the system’s damping to achieve better vibration damping performance and enhance driving comfort. In the energy recovery module, adjusting the duty cycle of the PWM signal input to the MOSFET can maintain a stable output voltage, ensuring a continuous and smooth power supply to the energy storage device. In order to obtained a better vibration damping performance, a dynamic controller for adjusting damping is designed. The simulation analysis is conducted, which demonstrates the proposed SERS system can significantly improve vibration damping performance of suspensions and shows excellent energy recovery performance.]]></description>
      <pubDate>Thu, 25 Jan 2024 11:08:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325750</guid>
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