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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" />
    <description></description>
    <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>
    </image>
    <item>
      <title>Vehicle height control of air suspension based on speed adaptive double-zone model prediction</title>
      <link>https://trid.trb.org/View/2617102</link>
      <description><![CDATA[The electronically controlled air suspension (ECAS) system improves the ride comfort and stability of the vehicle by adjusting the vehicle height. Due to the compressibility of air and the inertia of suspension, the ECAS system has the problem of excessive adjustment in the process of vehicle height adjustment, so that the solenoid valve is repeatedly opened and closed. Aiming at this problem, this paper proposes a new vehicle height control method based on speed adaptive double-zone model prediction control (AD-MPC), which realizes the adjustment of vehicle height with less operation of solenoid valve. Firstly, the single-wheeled air suspension is selected as the characteristic model and the spatial state equation is established. Then, the seeker optimization algorithm for the double-zone selection problem is designed to quickly find the best double-zone to obtain a double-zone function that can adapt to the speed. And then, the predictive control method based on AD-MPC is designed. Finally, the effectiveness and feasibility of the method are verified by simulation and experiment.]]></description>
      <pubDate>Tue, 02 Dec 2025 09:58:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2617102</guid>
    </item>
    <item>
      <title>Performance enhancements of semi-active vehicle air ISD suspension</title>
      <link>https://trid.trb.org/View/2563912</link>
      <description><![CDATA[To explore an innovative approach for enhancing the vibration isolation performance of vehicle air suspension systems, this study introduces the inerter element into the vehicle air suspension and investigates the dynamic behavior of the semi-active vehicle air ISD (inerter-spring-damper) suspension. Initially, a dynamic model of the quarter semi-active vehicle air ISD suspension is established, followed by conducting multi-objective optimization of the core parameters using the genetic algorithm. Subsequently, the dynamic performance of the semi-active vehicle air ISD suspension is thoroughly examined through simulations and analyses in both the time and frequency domains. The results demonstrate notable improvements in various aspects: the root-mean-square (RMS) value of the vehicle body acceleration in the semi-active vehicle air ISD suspension is reduced by 12.8%, the RMS value of the suspension working space is decreased by 37.3%, and the RMS value of the dynamic tire load experiences an 8.9% reduction. The findings of this paper indicate that the proposed semi-active vehicle air ISD suspension outperforms both the passive vehicle air suspension and the semi-active vehicle air suspension without an inerter, significantly enhancing the vehicle’s ride comfort, handling stability, and driving safety.]]></description>
      <pubDate>Fri, 21 Nov 2025 08:44:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2563912</guid>
    </item>
    <item>
      <title>A nonlinear model predictive control for air suspension in hub motor electric vehicle</title>
      <link>https://trid.trb.org/View/2506340</link>
      <description><![CDATA[The hub-motor electric vehicle (HM-EV) is considered as an ideal configuration for electric vehicles (EVs). However, the electromechanical coupling effect deteriorates HM-EV ride comfort, which limits its widespread application in EVs. In this study, the HM-EV dynamic system with air springs is proposed to intervene in vehicle attitude and ride comfort. The HM-EV dynamic model with air spring, considering the electromechanical coupling effect, is established and the test validation is investigated. Then quasi-infinite horizon nonlinear model predictive control (QIH NMPC) is designed to improve the longitudinal and vertical dynamic performance. The dynamic performance of passive suspension, air suspension based on QIH NMPC, air suspension based on MPC, and PID control receptively, are compared under several random road scenarios. Finally, the results indicated that the proposed control algorithm can improve ride comfort, reduce motor vibration, and improve longitudinal and vertical dynamic performance.]]></description>
      <pubDate>Thu, 13 Feb 2025 09:36:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2506340</guid>
    </item>
    <item>
      <title>A data-driven suspension kinematics and compliance model considering multi-axis coupling effects</title>
      <link>https://trid.trb.org/View/2506338</link>
      <description><![CDATA[The kinematics and compliance characteristics (K&C) significantly impact a vehicle’s dynamic response. While a comprehensive multibody suspension model can accurately express desired suspension K&C characteristics, the complexity of the model limits its use in real-time applications. The K&C characteristics are usually obtained through decoupled bench tests, whereby it is assumed that the suspension K&C characteristics can be orthogonally decomposed and that the function outputs can be added up to restore the original characteristics, which may not be accurate. Therefore, in this research, a novel suspension K&C simulation/test method is proposed to demonstrate the suspension characteristics under coupled force inputs. A multibody dynamic model of an air suspension is constructed and calibrated through bench tests. Then, a series of coupled tire forces with shapes of space spiral curves are applied to the multibody model to produce the coupled K&C data. A novel data-driven model based on Long Short-Term Memory (LSTM) network is proposed to predict suspension K&C. Finally, the proposed data-driven K&C model and the decoupled K&C model are compared under full vehicle simulations. The results suggest that the proposed method is more accurate than the decoupled K&C model and can express the suspension hysteresis characteristics without further modification.]]></description>
      <pubDate>Tue, 11 Feb 2025 09:13:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2506338</guid>
    </item>
    <item>
      <title>Model reference backstepping control for semi-active air suspension systems with parameter uncertainty</title>
      <link>https://trid.trb.org/View/2437569</link>
      <description><![CDATA[The electronically controlled semi-active air suspension systems have been widely used to improve the vehicle ride comfort and road holding performance by adjusting the damper stiffness. This work focuses on the design of a damping force controller to enhance the ride comfort, road holding and stability under the presence of unknown air spring pressure. Firstly, an improved skyhook suspension reference model is developed to generate the desired dynamic criteria (i.e. vehicle body acceleration, pitch and roll angles). Secondly, by employing the backstepping technique, a novel damping force controller is proposed to approach the desired dynamic criteria. Thirdly, a parameter estimation method is also designed to estimate the air spring pressure to obtain the air spring force. Comparative studies are carried out among passive suspension systems, and the semi-active air suspension systems with the proposed model reference damping force control, traditional backstepping control and existing sliding mode control. Numerical results show that a significant improvement of ride comfort can be observed with the semi-active air suspension system based on the proposed model reference backstepping controller.]]></description>
      <pubDate>Mon, 21 Oct 2024 13:33:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/2437569</guid>
    </item>
    <item>
      <title>Modeling and state-preview height control of electronically controlled air suspension system based on experiment</title>
      <link>https://trid.trb.org/View/2437591</link>
      <description><![CDATA[In the control of electronically controlled air suspension system (ECAS), the precision and stability of height control are important targets to measure the efficiency. In the control process of an ECAS system, the phenomenon of “overinflation,”“overdeflation,” and frequent inflating and deflating is commonly existed, which is rooted in the hysteresis characteristic of the system. Based on the bench test, the system identification and quantitative performance analysis of solenoid valves and air springs were carried out, and a refined ECAS system model was built. A PID control strategy is optimized and a state-preview height control strategy is established. AMESim and Simulink are used to build the vehicle and controller models. The accuracy of the model is verified by the comparison between the co-simulation and the field test, and the conclusion is drawn that the state preview height control strategy can improve the smoothness of the height control.]]></description>
      <pubDate>Fri, 18 Oct 2024 13:42:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2437591</guid>
    </item>
    <item>
      <title>Research on design and characteristic of a new type of air suspension system with magnetic negative quasi-zero stiffness</title>
      <link>https://trid.trb.org/View/2329960</link>
      <description><![CDATA[This paper designs a quasi-zero stiffness suspension with an air spring and a magnetic spring in parallel to improve the vehicle ride comfort. The proposed new suspension does not change the overall layout of the air suspension or affect the handling stability, reducing the system’s natural frequency by a sound vibration isolation effect for a low-frequency vibration and finally improving ride comfort. The feasibility of quasi-zero stiffness suspension is verified by mathematical modeling of air spring and magnetic spring, and reasonable structural parameters are set for the simulation experiment. The 1/4 vehicle model with two degrees of freedom is built in MATLAB / Simulink. Select body acceleration, suspension working space, and tire dynamic load as evaluation indexes to test the comfort performance of the proposed suspension. The result shows that the proposed new suspension has a noticeable effect on reducing the acceleration of the vehicle body and significantly improves the vehicle ride comfort.]]></description>
      <pubDate>Mon, 05 Feb 2024 09:35:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2329960</guid>
    </item>
    <item>
      <title>Influence of suspension schemes on medium-low speed maglev vehicle-guideway dynamic interaction</title>
      <link>https://trid.trb.org/View/2310063</link>
      <description><![CDATA[A comparative study was conducted on Levitation Frame with Mid-set Air Spring (LFMAS) and Levitation Frame with End-set Air Spring (LFEAS). First of all, the work done by air spring force and by track excitation on two levitation frames were analysed, respectively, and the mechanism of the low dynamic interaction of LFMAS with guideway was explained theoretically; then, dynamics simulation and coupled vibration test on LFEAS and LFMAS were carried out using coupled vibration test bench of single levitation frame. Theoretical equations show that both the work done by the air spring forces and by track excitation on LFMAS are less than those on LFEAS under the same vibration condition, demonstrating that LFMAS has better levitation stability than LFEAS. Simulation and test results show that the fluctuation of levitation gap as well as the vibration acceleration of track beam platform, levitation frame and car-body of LFMAS are all smaller than those of LFEAS; with the increase of sine excitation frequency or vehicle speed, the superiority of LFMAS in dynamics performance is more obvious.]]></description>
      <pubDate>Tue, 02 Jan 2024 09:19:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2310063</guid>
    </item>
    <item>
      <title>Fixed-Time Control for a Quadrotor With a Cable-Suspended Load</title>
      <link>https://trid.trb.org/View/2059404</link>
      <description><![CDATA[This paper is concerned with the motion control for a quadrotor with a cable-suspended load (QCSL). A fixed-time control strategy is presented to improve the transient response and robustness of the QCSL with external disturbance. The overall control scheme is designed with a cascade structure to better cope with the underactuated property of the QCSL and the indirect effect of the control force on the load’s velocity through the tensile force on the cable. The simulation results are given to demonstrate the performance of the proposed scheme. Furthermore, actual flight tests were performed on a new experimental QCSL to validate the effectiveness of the proposed control strategy.]]></description>
      <pubDate>Tue, 28 Feb 2023 09:20:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2059404</guid>
    </item>
    <item>
      <title>Research on nonlinear model and fuzzy fractional order PIλDμ control of air suspension system</title>
      <link>https://trid.trb.org/View/1949052</link>
      <description><![CDATA[To improve the ride comfort of wheeled armored vehicles, air springs are used. To describe the vehicle motion more accurately, a nine-degree-of-freedom air suspension system for the whole vehicle was established, and its equations of motion were derived. Through theoretical analysis of the stiffness characteristics and forces on the air springs, the nonlinear restoring force was obtained as a cubic polynomial of the air spring displacement. The simulation results obtained by fitting the polynomial and radial basis function curves with MATLAB/Simulink software are consistent with the actual test results, thus verifying the correctness of the nonlinear air spring polynomial model. Finally, a fuzzy fractional order PIλDμ controller is designed and simulated for the vehicle-seat-body model in terms of wheel dynamic load, suspension dynamic deflection, body acceleration, and other indicators. The simulation results show that the fuzzy fractional order PIλDμ Proportion Integral Differential (PID) control strategy has better overall performance than the PID control strategy, fuzzy control strategy, and fuzzy PID control strategy.]]></description>
      <pubDate>Tue, 28 Jun 2022 09:43:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/1949052</guid>
    </item>
    <item>
      <title>Design and Development of Front Air Suspension for Front Engine Bus with Floor at Entry Plus One Step</title>
      <link>https://trid.trb.org/View/1826768</link>
      <description><![CDATA[The automotive industry is heading towards introduction of newer and newer technology aimed at providing better comforts and value to the end user. The public/ private transport vehicles in urban/rural areas with FE has wide level of acceptance in South East Asian countries. The acceptance of FE buses is mainly because of the ram air cooling of the engine, lesser maintenance, higher fuel efficiency, etc., whereas rear engine buses with entry plus one step are deprived of these benefits. Hence, the authors have designed and developed a new Front Engine Semi -Low Floor bus having floor at E+1 step. The primary design challenge was to meet the uniform floor throughout the length of the vehicle. This uniqueness will help in easy ingress and egress of the passengers which helps in reducing the turn around rime of the vehicle. Other challenges includes, meeting the customer requirements in terms of application, load and duty cycle for this new design. Commercial Vehicle industry in India finds reliability as one of the most interesting subjects to work on, as it has significant impact on warranty cost (for manufacturer) and on product uptime (for customers), both of which are definitely the key parameters that define the products success. This paper explains the design and validation challenges faced during the development of front air suspension for front engine bus having floor at E+1. First half of the paper explains the design challenges and their solutions during the design and development of front air suspension for front engine bus having floor at E+1 and second half explains the validation challenge i.e. to optimize the validation method for this design. This has been done by closely co-relating the RLDA and the rig level testing of the front suspension of a typical front engine bus. The RLDA was captured at specified points and these points were derived based on the high stress areas in CAE analysis. The RLDA was then converted into block cycles and the rig level testing is carried out for the braking plus vertical load case. This co-relation activity helps in reducing the validation time. The future scope of the study includes the extending same exercise for other load cases i.e. cornering plus vertical and vertical load case so that the complete testing time can be optimized.]]></description>
      <pubDate>Tue, 24 May 2022 10:05:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/1826768</guid>
    </item>
    <item>
      <title>Engineering design of a manipulator for mounting an air suspension compressor to a car chassis</title>
      <link>https://trid.trb.org/View/1908995</link>
      <description><![CDATA[This article is aimed at the engineering design of a manipulator, which is pneumatically controlled. It will serve for mounting the compressor of an air suspension system to the chassis of a sport utility vehicle (SUV) produced in the Slovak Republic. The manipulator will be used on an assembly line, on which SUVs are assembled. The designed device belongs to a group of dedicated devices, which are not produced within a serial production, however, it is the only functional prototype. Together with the manipulator structure, a pneumatic part of the assembly line including individual components, schemes and the pneumatic system will be proposed. Within the project process, all necessary customer demands, technical and safety standards have to be met. Moreover, ergonomic requirements for handling the device and other acts on the workplace have to be considered.]]></description>
      <pubDate>Wed, 20 Apr 2022 16:15:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1908995</guid>
    </item>
    <item>
      <title>Application of machine learning approach on improving quality of semi-trailer truck air suspensions</title>
      <link>https://trid.trb.org/View/1903443</link>
      <description><![CDATA[A combination of the machine-learning-approach (MLA) and optimal-fuzzy-logic-control (OFLC) is proposed for semi-trailer truck air suspensions to enhance the ride-quality and road-friendliness. A dynamics model of semi-trailer truck is built for the simulation. The root-mean-square accelerations of the vertical vibration (awzd), pitching (awφd), and rolling angle (awθd) of the tractor driver, and dynamic load-stress factor (κ) of wheel-axles are selected as indexes. Based on the data map of road surfaces and optimal rules of OFLC, the MLA is developed to control semi-trailer truck air suspensions. Results show that vehicle air suspensions optimised by OFLC and MLA are overall superior to passive air suspensions under different simulations. Especially, the awzd, awφd, awθd, and κ with MLA are markedly reduced by 13.29%, 11.05%, 17.78%, and 11.41% compared to OFLC under combined roads of level-E, level-C, and level-D. Consequently, the vehicle's ride-quality and road-friendly are further enhanced by applying MLA.]]></description>
      <pubDate>Mon, 28 Feb 2022 09:42:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1903443</guid>
    </item>
    <item>
      <title>An investigation into the ride comfort of buses using an air suspension system</title>
      <link>https://trid.trb.org/View/1862652</link>
      <description><![CDATA[The paper focuses on the ride comfort criteria of a two-axle bus using an air suspension system. First of all, based on the Gensys model, a nonlinear model of an air spring element linked to an auxiliary air tank is investigated. The parameters of the air spring model are determined through real experiments in both static and dynamic load modes with the error between the theoretical simulation model and the real experimental data being less than 8%. Then, a full bus model using the dependent suspension system takes into account the driver model mentioned in two cases of using air suspension and leaf suspension. Simulation results in the time domain with different motion states show that the ride comfort of the bus using air suspension system is improved by about 20%, when compared to the bus using the leaf suspension system. Meanwhile, the road holding criteria are maintained.]]></description>
      <pubDate>Mon, 26 Jul 2021 15:48:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1862652</guid>
    </item>
    <item>
      <title>Development of Quasi-static Curve Negotiation Analysis Procedure Considering Hysteretic Behavior of Air Suspension Systems</title>
      <link>https://trid.trb.org/View/1853260</link>
      <description><![CDATA[Whereas air suspension is widely used for railway vehicles as secondary suspension, its hysteretic behavior possibly exerts a non-negligible influence on a vehicle's running characteristics, including unwanted wheel load variations in curves. To enable accurate and quick prediction of vehicle curve negotiation performances considering hysteretic air suspension behavior, this study proposes a new quasi-static curve negotiation analysis procedure using a thermodynamic air suspension system model that expresses in detail nonlinear airflow characteristics. This approach allows the elimination of the limitations of existing full dynamic simulation models associated with high computational intensity and is suited for vehicle running simulations over long-distances.]]></description>
      <pubDate>Fri, 25 Jun 2021 18:36:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/1853260</guid>
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