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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>Fixed-Time Constraint-Aware Sliding-Mode Control for Ride Comfort Enhancement in Active Vehicle Suspensions</title>
      <link>https://trid.trb.org/View/2732069</link>
      <description><![CDATA[Active vehicle suspensions must improve ride comfort while respecting strict suspension-travel and tire-load constraints under uncertain road disturbances. Although sliding-mode control ensures robustness, conventional designs provide only asymptotic convergence and may generate chattering, limiting transient predictability and practical implementation. This paper proposes a continuous, non-singular fixed-time sliding-mode controller (FxT-SMC) with explicit constraint awareness for nonlinear quarter-car active suspensions. A state-dependent sliding map guarantees fixed-time convergence with an initial-condition-independent settling-time bound, while a smooth reciprocal barrier embedded in the sliding surface enforces forward invariance of the admissible travel set without discontinuous projection. Global fixed-time stability and bounded zero dynamics are rigorously established via Lyapunov analysis. Experimental validation over representative road profiles demonstrates predictable sub-2-second transients, strict satisfaction of travel and tire-load limits, and significant improvements in ISO 2631-1 comfort metrics compared with passive suspension, classical SMC, and super-twisting control. The results highlight the effectiveness of fixed-time, constraint-aware sliding-mode control for practical intelligent active suspension systems.]]></description>
      <pubDate>Wed, 12 Aug 2026 15:14:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2732069</guid>
    </item>
    <item>
      <title>Comfort Study of Air Suspension System Based on MPC Control</title>
      <link>https://trid.trb.org/View/2742523</link>
      <description><![CDATA[Air springs are increasingly replacing traditional shock absorbers in vehicle suspension systems due to their superior mechanical properties, including adjustable stiffness, nonlinear characteristics, and excellent damping performance. To further explore the potential of air suspension in improving ride comfort, this paper focuses on air suspension. We first conducted mechanical characteristic experiments on air springs to obtain their stiffness and damping characteristics under different inflation pressures and excitation frequencies. These tests provide essential mechanical parameters for subsequent modeling and simulation. Based on the experimental data, a simplified 1/4 air suspension simulation model is constructed, taking into account the nonlinear stiffness and damping properties of the air springs. To simulate real-world driving conditions, a random road surface model is introduced as the excitation input. Simulation analysis is conducted to compare the air suspension system with the traditional passive suspension system. The results indicate that, compared to the passive suspension system, the air suspension system integrated with Model Predictive Control(MPC) significantly reduces key performance indicators, including suspension deflection, wheel dynamic load, and sprung mass vertical acceleration. This indicates that the suspension with model predictive control can effectively suppress vehicle vibrations, thereby enhancing ride comfort and driving stability. The results of this study provide an important basis for the optimal design of air suspension systems and have practical application value for improving the suspension performance of the vehicle.]]></description>
      <pubDate>Mon, 03 Aug 2026 15:36:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2742523</guid>
    </item>
    <item>
      <title>Improving Ride Comfort in Autonomous Vehicles with Fractional-Order SMC Active Suspension under Road Uncertainties</title>
      <link>https://trid.trb.org/View/2713928</link>
      <description><![CDATA[Ensuring ride comfort, handling stability, and road adaptability is crucial for developing smart and resilient transportation systems. This paper presents a novel Fractional-Order Sliding Mode Control (FOSMC) strategy for active suspension systems in Connected and Autonomous Vehicles (CAVs/AVs), aiming to enhance ride comfort and robustness under varying road and load conditions. Unlike conventional integer-order SMC approaches, the proposed FOSMC integrates fractional calculus into the sliding surface design, introducing memory and hereditary dynamics that more accurately represent vehicle behavior. This framework mitigates the effect of disturbances, reduces chattering, and enhances actuator operation for intelligent and efficient mobility solutions. The controller’s stability is rigorously analyzed using Lyapunov theory, confirming global asymptotic stability. Simulation results demonstrate that the proposed FOSMC reduces suspension defection by 36%, and control chattering by more than 50% when compared to traditional SMC, demonstrating its potential to improve comfort, stability, and safety in intelligent mobility applications.]]></description>
      <pubDate>Mon, 27 Jul 2026 11:16:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2713928</guid>
    </item>
    <item>
      <title>Optimal Control of Active Quarter-Car Suspensions Using PSO/TLBO-based Optimization and LQR/LQG Strategies under ISO Road Excitations</title>
      <link>https://trid.trb.org/View/2713875</link>
      <description><![CDATA[This paper presents a systematic comparison of PID, LQR, LQG and SMC controllers for active quarter-car suspension, focusing on balancing ride comfort, handling stability, and control effort. PID gains and LQR weighting matrices are optimized using Particle Swarm Optimization (PSO) and Teaching-Learning-Based Optimization (TLBO) algorithms. Performance is evaluated on half-sine bump and ISO 8608 random road profiles, with key metrics including RMS body acceleration, suspension and tire defections, actuator effort, and transient response features such as overshoot and settling time. Statistical analysis over 20 randomized runs reveals that LQR controllers tuned via TLBO and PSO maintain ride comfort comparable to passive suspension while significantly reducing suspension defection and control effort. PID controllers achieve moderate improvements but incur higher actuator effort and suspension travel. LQG offers minor gains over passive suspension but does not outperform optimized LQR controllers. These findings provide practical guidance for designing active suspension controllers that efficiently trade of comfort, stability, and actuator usage in realistic driving conditions.]]></description>
      <pubDate>Mon, 27 Jul 2026 11:16:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2713875</guid>
    </item>
    <item>
      <title>Game-Theoretic Control with Learning-Aware Dynamic Event-Triggered Communication for Vehicle Active Suspension Systems</title>
      <link>https://trid.trb.org/View/2727919</link>
      <description><![CDATA[One critical technology enabling the autonomous operation of intelligent vehicles is the active suspension control, which is responsible for regulating ride comfort, road handling and so on. This paper concentrates on this problem by presenting a novel learning-aware dynamic event-triggered control scheme under limited communication resources and parameter uncertainties. First, the dynamics model of quarter-vehicle suspension is established and its active control problem is formulated as a two-player zero-sum differential game problem containing a joint cost function. Then, relying on event-triggered communication, an actor-critic adaptive learning algorithm is proposed through integral reinforcement learning and weighted experience replay technique. This algorithm can online approximate the optimal control policy against disturbance in the case of unknown internal dynamics. Furthermore, two learning-aware dynamic event-triggered mechanisms are designed for more flexible scheduling of communication resources, enabling the system to dynamically adjust the triggering process based on the learning status and state variations. A distinctive feature of these two mechanisms is their seamless integration into the learning algorithm via dynamic threshold parameters, thereby balancing multiple performance requirements. Finally, the performance of the proposed scheme is demonstrated through a nonlinear example, and further validated on an active suspension system via various simulation scenarios and comparative experiments.]]></description>
      <pubDate>Mon, 27 Jul 2026 11:16:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/2727919</guid>
    </item>
    <item>
      <title>Finite time energy-saving control of active suspension based on force random walk PSO</title>
      <link>https://trid.trb.org/View/2666860</link>
      <description><![CDATA[To reduce energy consumption in the active suspension, this paper proposes a new method for vehicle active suspension control. The energy consumption characteristics of the coupling system is analyzed. On this basis, a finite time controller based on unknown state estimation is proposed, and its global finite time convergence is proved, the upper limit of time convergence is given. Secondly, based on Analytic Hierarchy Process (AHP) and the force random walk PSO algorithm (FRWPSO), a multi-objective optimization function is constructed to determine the control parameters under different driving modes. Finally, simulation experiments show that under random road surfaces and triangular obstacles, the proposed control method can effectively improve suspension comfort and operational stability compared to nonsingular terminal sliding mode control (TSMC), The RMS values of energy consumption decreased by 55.34% and 20.55% respectively, verifying the effectiveness of the proposed control method.]]></description>
      <pubDate>Mon, 27 Jul 2026 09:46:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666860</guid>
    </item>
    <item>
      <title>Preview-based MPC for active suspension control of tank vehicle with lateral liquid sloshing suppression</title>
      <link>https://trid.trb.org/View/2666859</link>
      <description><![CDATA[This paper proposes an active suspension control method for tank vehicle, which can effectively suppress the lateral sloshing of liquid cargo, so as to improve the tank vehicle’s roll stability under the coupling excitation of non-structural road environment and additional moments of liquid cargo. Firstly, to describe the additional moments generated by the liquid cargo when the vehicle is laterally excited, a liquid sloshing equivalent mechanical pendulum model is put forward. Further, realizing the significant influence of road parameters on the roll stability of the vehicle, the liquid-vehicle-road coupling model is derived under the consideration of road curvature and cross-slope. Subsequently, based on the road information obtained in advance, a preview-based model predictive control (MPC) controller is designed to improve the roll stability of the tank vehicle and suppress the lateral sloshing of the liquid. Finally, the simulation is verified based on Matlab/Simulink under two complex scenarios, which indicates that the proposed control method can achieve better control effect compared with the traditional linear quadratic regulator (LQR) controller.]]></description>
      <pubDate>Mon, 27 Jul 2026 09:46:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666859</guid>
    </item>
    <item>
      <title>Modeling and Damping Optimization Design of Commercial Vehicle Cab Air Suspension System</title>
      <link>https://trid.trb.org/View/2732209</link>
      <description><![CDATA[Based on the theory of vehicle dynamics, this paper first constructs a dynamic model of the cab air suspension system, laying a core theoretical framework for subsequent optimization research. At the level of performance evaluation indicators, the root mean square (RMS) values of the cab’s vertical acceleration, roll acceleration, and pitch acceleration are selected as key parameters. On this basis, an objective function for the damping matching of the cab air suspension system is established, clarifying the optimization direction. Building on this objective function, the paper further takes into account the constraint conditions in the actual operation of the system, using the probability of the cab air suspension system hitting the limit stop as a constraint. Finally, a complete mathematical model for the damping matching of the cab air suspension system is formed, and a genetic algorithm is used to solve this model, ensuring the scientificity and feasibility of the optimization results. To verify the effectiveness of the established model and optimization method, this paper conducts verification based on the aforementioned dynamic simulation model of the cab air suspension system: the frame displacement signals collected under actual random road conditions are used as the model input, and the established mathematical method for damping matching is applied to carry out the optimal matching design of the damping parameters of the cab air suspension system. The simulation optimization results show that the performance of the optimized system is significantly improved: the RMS value of vertical acceleration is reduced by 5% compared with that before optimization, the RMS value of roll angular acceleration is reduced by 11.2%, and the RMS value of pitch angular acceleration is reduced by 4.7%. In conclusion, the method constructed in this paper can effectively improve a practical and feasible reference for the damping optimization design of the cab suspension system.]]></description>
      <pubDate>Tue, 21 Jul 2026 11:33:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2732209</guid>
    </item>
    <item>
      <title>Hierarchical control of vehicle active suspension system with uncertain sprung mass and time-varying disturbance</title>
      <link>https://trid.trb.org/View/2680749</link>
      <description><![CDATA[A hierarchical control strategy is proposed for nonlinear uncertain active suspension systems. To provide the target force needed for the suspension, the top controller is built with a sliding mode controller that is based on a nonlinear disturbance observer. To precisely follow the goal force, the bottom controller is made in the style of a backstepping adaptive controller. Coordinated control of the suspension dynamic displacement and sprung mass acceleration of the nonlinear uncertain suspension system is realized by the controller. Firstly, a nonlinear filter is incorporated to maintain the vehicle body’s vertical motion stability while meeting the suspension’s mechanical structural limitations. Secondly, the nonlinear disturbance observer is used to compensate the influence of uncertain sprung mass, mechanical structure nonlinearity and external disturbance. Thirdly, a coordinated adaptive backstepping tracking controller to estimate the uncertain parameters resulting from the physical characteristic change of the electro-hydraulic actuator is designed using backstepping technology and Lyapunov stability theory. This allows the control object to precisely track the goal force generated by the upper controller and guarantee the body’s stability. Finally, the effectiveness of the hierarchical controller is analyzed under random road, bumpy road conditions.]]></description>
      <pubDate>Tue, 30 Jun 2026 15:52:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2680749</guid>
    </item>
    <item>
      <title>Optimization Control of Automotive Active Suspension Based on Deep Deterministic Policy Gradient Algorithm</title>
      <link>https://trid.trb.org/View/2711447</link>
      <description><![CDATA[The suspension system of a car is a core component that affects the smoothness and handling stability of the vehicle. Compared to traditional passive and semi-active suspensions, active suspension has greater potential for performance improvement by actively outputting control force through actuators. However, the design of its controller faces challenges such as model uncertainty, road excitation randomness, and multi-objective optimization. This article proposes an active suspension optimization control strategy based on the Deep Deterministic Policy Gradient (DDPG) algorithm. Firstly, a two degree of freedom 1/4 vehicle active suspension dynamic model was established, which includes actuator dynamics. Subsequently, a comprehensive reward function was designed with the optimization objectives of vehicle vertical acceleration, suspension dynamic stroke, and tire dynamic load, taking into account both actuator output force and energy consumption. The intelligent agent (Actor Critic network) learns the optimal control strategy through continuous interaction with the environment (suspension model), without relying on an accurate system model. The simulation experiment was conducted on the MATLAB/Simulink platform, using filtered white noise to simulate random road inputs. The results show that compared with traditional methods such as linear quadratic regulator and ceiling damping control, the proposed DDPG controller reduces the vertical acceleration (smoothness) of the vehicle body by about 31.2% and 22.5%, while constraining the suspension dynamic stroke and tire dynamic load within safety limits, demonstrating superior comprehensive performance and robustness. This study provides new ideas for intelligent control of active suspension under complex working conditions.]]></description>
      <pubDate>Tue, 30 Jun 2026 09:45:06 GMT</pubDate>
      <guid>https://trid.trb.org/View/2711447</guid>
    </item>
    <item>
      <title>Development and implementation of an advanced robust control strategy for quarter-car active suspension systems</title>
      <link>https://trid.trb.org/View/2701313</link>
      <description><![CDATA[This study investigates the development of an advanced robust control strategy for a quarter-car active suspension system to optimize ride comfort and road handling. Traditional PID controllers struggle with trade-offs between comfort and stability under real-world conditions like variable road profiles and parametric uncertainties. To address this, we propose a novel H8 robust control integrated with µ-synthesis, explicitly handling uncertainties in suspension parameters (sprung/unsprung mass, stiffness, damping, tire stiffness). Mathematical modeling and MATLAB/Simulink simulations demonstrate significant improvements: a 54% reduction in peak vertical body acceleration (3.95 m/s2 to 1.816 m/s2) and a 35% decrease in suspension deflection (0.078 m to 0.020 m) compared to passive systems. Frequency-domain analysis shows a 92.42% reduction in resonance peaks at 10 rad/s, with over 30% energy savings. Time-domain simulations confirm stability under transient disturbances, with actuator forces constrained to ±1.3 kN. The integration of µ-synthesis with H8 control efficiently manages parametric variations and unmodeled dynamics. Comparative evaluations highlight the approach’s superiority over passive and conventional active systems, offering promising applications for autonomous and electric vehicles. This work lays the groundwork for future research on adaptive, energy-efficient suspension systems.]]></description>
      <pubDate>Tue, 30 Jun 2026 09:45:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2701313</guid>
    </item>
    <item>
      <title>New improved on–off damping force control algorithm for modern hybrid-damper-based lateral suspension systems in railway vehicles</title>
      <link>https://trid.trb.org/View/2701300</link>
      <description><![CDATA[Pure semiactive suspension systems combine the advantages of passive and active suspension systems to achieve superior performance. The robustness of pure semiactive suspension systems remains limited under certain conditions, such as those involving power loss, actuator failures, or sensor failures. To address these problems, the present study developed a modern hybrid-damper-based lateral suspension system that uses a new improved on–off damping force control algorithm. This modern suspension system integrates a conventional passive suspension system with a semiactive magneto-rheological damper, while the new control algorithm generates a constant yield stress force or zero yield stress force for the damper, based on a vibration velocity-threshold of car body. The performance of the developed method was evaluated primarily using simulations with a quarter railway vehicle model developed in MATLAB/Simulink under harmonic oscillation of railway tracks. The simulation results indicated that within a low-frequency range below 3 Hz, the proposed method outperformed a conventional passive suspension system and a modern suspension system employing a skyhook control algorithm, with the car body acceleration produced with the proposed method in the quarter railway vehicle model being 53.79% and 6.7% lower than those produced with the other two systems, respectively. Moreover, a comprehensive evaluation was performed using a full railway vehicle model developed in SIMPACK, with a mass rapid transit route, track irregularities, and crosswind effects considered to replicate real-world operating conditions. In the full railway vehicle model, the proposed method improved passenger comfort and running safety, reducing the root mean square of comfort index by 21.14% and 15.47% compared with the conventional passive suspension system and modern suspension system employing a skyhook control algorithm, respectively, and decreasing the peak values of derailment coefficient by 13.86% and 13.03% compared with the conventional passive suspension system and modern suspension system employing a skyhook control algorithm, respectively. In conclusion, the proposed method demonstrates high ride quality, high safety level, and practical feasibility, offering significant potential for real-world applications. However, experimental research is needed to further validate our simulation results.]]></description>
      <pubDate>Tue, 30 Jun 2026 09:45:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2701300</guid>
    </item>
    <item>
      <title>Can seat suspensions mitigate motion sickness and enhance vibration comfort while being driven? A subjective assessment of the K-Seat</title>
      <link>https://trid.trb.org/View/2681559</link>
      <description><![CDATA[Prolonged exposure to whole-body vibration (WBV) is a key contributor to motion discomfort in vehicles, including motion sickness and ride comfort. This issue becomes more compelling in automated vehicles, where occupants are expected to frequently engage in non-driving-related activities and will expect high comfort levels. Hence, enhancing seat design to mitigate WBV is essential for improving ride comfort across vehicle types. Therefore, this study, which primarily addresses vertical accelerations, optimized an existing seat suspension (K-Seat) and subjectively assessed discomfort using 24 participants (13 males and 11 females) exposed to a 29-minute driving session. The experiment was conducted with a conventional Toyota Yaris seat in a driving simulator, where a K-Seat model was used to emulate the effect of the seat suspension. Thus we evaluated the K-Seat, which has shown great promise for attenuating low-frequency vibrations; however, it had never been tested on human participants. The results show an overall reduction of 50% in reported motion sickness using the motion illness symptoms classification scale (MISC). Subjective discomfort was also alleviated for head and upper back. In addition, perceived discomfort was analyzed based on gender, illustrating a greater effectiveness of the K-Seat in enhancing lower neck comfort for females than for males.]]></description>
      <pubDate>Thu, 18 Jun 2026 08:54:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2681559</guid>
    </item>
    <item>
      <title>A Novel Stiffness Prediction Model of Rolling Lobe Air Springs
                    Considering Irregular Piston Contour Geometry: Development and Experimental
                    Validation</title>
      <link>https://trid.trb.org/View/2706185</link>
      <description><![CDATA[
                
                An accurate air spring model is essential for the design and optimization of air
                    suspension systems to achieve superior performance. This article presents a
                    novel stiffness model for a rolling lobe air spring (RLAS), formulated using
                    stiffness characteristic parameters. Prediction models for these parameters,
                    including effective area and its change rate, as well as effective volume and
                    its change rate, are derived through geometric analysis, based on polynomial
                    fitting of the irregular piston contour. The local contour cone angle of the
                    piston is determined by differentiating the polynomial function, capturing the
                    geometry-dependent variation across the profile. Additionally, a nonlinear
                    hysteresis model for the rubber bellows is integrated, combining a Berg friction
                    component and a Kelvin-Voigt fractional derivative viscoelastic model to
                    represent the amplitude- and frequency-dependent behavior of the RLAS. The
                    proposed model is parameterized through quasi-static and dynamic bench tests
                    under varying amplitudes and frequencies and is validated against both
                    experimental data and an existing modeling approach. Comparative results
                    demonstrate that the proposed model effectively and accurately predicts the
                    static and dynamic responses of the RLAS.
            ]]></description>
      <pubDate>Tue, 26 May 2026 17:03:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/2706185</guid>
    </item>
    <item>
      <title>A fully active automotive suspension based on a rotary hydraulic valve</title>
      <link>https://trid.trb.org/View/2701188</link>
      <description><![CDATA[Active suspensions are commonly used in high-end vehicles to improve ride comfort and road holding. Commercial hydraulic active suspensions for cars typically employ directional solenoid valves to control hydraulic fluid flow, thereby modifying the dynamic behavior of output actuators. However, these valves require fast, accurate actuation, which is often hindered by their intrinsic nonlinear behavior. This research presents a fully active suspension based on the use of a novel rotary valve. The proposed design is compact and highly integrated with a permanent-magnet synchronous machine for precise position control. To test its validity, a prototype of the actuation system is simulated, built and tested. Experiments on the position control loop of the valve spool demonstrate that the proposed system is able to fulfill the necessary actuation bandwidth for an automotive suspension. Static and dynamic experiments on the actuator output validate the ability to yield forces in the four quadrants of the force-speed plane.]]></description>
      <pubDate>Wed, 20 May 2026 09:10:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2701188</guid>
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