Browse Topic: Chassis

Items (14,809)

Analysis and Elimination of Transient Impact of Rollers in S-cam Brakes

2026-01-5066

To be published on 08/05/2026

S-cam brake is a drum-type foundation brake used in heavy commercial vehicles. It is a safety-critical device; hence, thorough validation of its performance by lab test rigs and field tests is essential. During prototype testing, an unusual impact was observed during dynamic braking at high pressure application, specifically when the brake drum is rotating, after a period of operation of about 10,000 cycles. This phenomenon was then observed even at static braking when the brake drum was at rest. From initial inspection, it is due to the cam roller, which rides on the web-slot provided at the shoe assembly, while the S-cam is rotating and falls back instantly. This phenomenon occurs repeatedly and creates an audible noise, which needs to be eliminated. The study aims to correlate the phenomenon using finite element analysis (FEA) as in a prototype test and to identify the root cause and optimize the design variables. Since the friction coefficient at the cam roller–web interface is unknown after a period of operation, different values of friction coefficient, ranging from 0.1 to 0.8, are iterated and simulated by rotating the S-cam until the braking effort is reached. The dynamic implicit analysis procedure in Abaqus standard is used to simulate this condition. Based on the results, design variables were improved to mitigate the issue. A quick solution, achieved by modifying a minor feature, successfully prevented the fallback behavior and was validated through physical testing. Furthermore, a permanent solution was developed to eliminate both the “ride-on” and “fallback” phenomena by optimizing component dimensions. This FEA methodology helps to validate the design in an initial concept phase itself for future variants. Using this method, even the structural and fatigue performance of braking parts can be validated at a system-level simulation with better accuracy.

Dinesh Kumar, J., Riyaz Mohamed, D., Vasanth Bharath, S., Rajkumar, S., Murugan, S.

Comparative Analysis of CDTire Model and FTire Model in Vehicle Comfort and Durability Simulation

2026-99-0109

7/31/2026

This paper studies the applicability of the CDTire tire model in vehicle comfort and durability simulations by comparing it with the FTire tire model. Based on a physical 250/50 R19 tire, the corresponding CDTire and FTire models are developed and integrated into a multibody dynamics model of an SUV. After simulations of two handling comfort conditions and one durability condition using the CDTire and FTire models, it is found that, when FTire is used as the base case, CDTire produces a smaller relative error in vehicle comfort simulation, with a maximum of +5.6%. In the durability simulation, the relative error is larger, but the maximum value remains within ±10% at + 9.7%. Therefore, it can be concluded that CDTire is one tire model with acceptable simulation accuracy for vehicle comfort and durability.

Gao, Fengling, Wu, Wenwen, Geng, Hao

Solution of Optimal Parameters of Leaf Springs by Firefly Algorithm Based on Penalty Function

2026-99-0144

7/31/2026

The probe is an important component of the precision instrument. During the measurement process, the deformation of the leaf spring directly affects the accuracy of the displacement of the probe. There are many undetermined parameters for the leaf spring, and some parameters have a non-linear impact on the results. This paper proposes a firefly algorithm that combines penalty functions to solve the optimal solution of the objective function for multi parameter leaf springs. Through strategies such as normalizing mapping intervals, setting small populations between cells, and fine-tuning position update formulas, this algorithm quickly obtains the optimal parameters of the leaf spring, and compares it with the orthogonal experimental method to prove the feasibility of this method, providing a certain theoretical reference value for multi parameter solving.

Yu, Jianghao, Shi, Zhaoyao, Song, Huixu

Comfort Study of Air Suspension System Based on MPC Control

2026-99-0136

7/31/2026

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.

Yin, Zhi

Study on Penetration Damage Characteristics of Honeycomb Non-pneumatic Safety Tiree

2026-99-0167

7/31/2026

To improve the mobility and reliability of special-purpose vehicles that are operated in extreme conditions and to minimize the influence of tire failure on the vehicle’s mobility, this paper investigates how the mechanical properties of honeycomb non-pneumatic tires are affected after high-speed impacts from external projectiles. A prototype of a network non-pneumatic honeycomb tire was initially developed, which was made of polyurethane material. The five parameter model of the Mooney-Rivlin model was selected as its constitutive relation and the experimental study was performed to validate three-dimensional stiffness simulation model for the tire. Secondly, a LS-DYNA-based finite element model was developed to describe the dynamic behaviors of the tire under an external impact at various locations (e.g. tread, single spoke plate and joints), and to investigate the influence of local damage and spoke plate fracture on the stiffness of the tire. The results indicate that the tire has better performance of resisting the impacts at small and medium levels, with the decrease of radial stiffness of the tire less than 4% after experiencing the ultrahigh load; after the spokes plate is broken, the radial stiffness of tire drops significantly by comparing with the intact tire, that is 24.17%, which has a great effect on the support performance of the tire. The findings of this work offer theoretical support and design guidelines for the structural optimization and properties improvement of NPTS.

Yao, Tuzao, Sun, Xiaowang, Zhang, Qiang, Fu, Lei, Huang, Jianbin

Design and Research of Robotic Arm for Belt Conveyor Roller Replacement

2026-99-0187

7/31/2026

To address the high failure rate of rollers in coal mine belt conveyors, the inefficiency of manual replacement, and the operational disruptions caused by maintenance shutdowns, this study proposes a robotic arm system capable of replacing rollers without halting conveyor operations. The research focuses on the kinematic performance and path planning strategy of the robotic arm. A kinematic model is established using the Denavit–Hartenberg (DH) parameters, and the workspace distribution is analyzed via the Monte Carlo method. The results show that the horizontal reach exceeds 2020 mm and the vertical reach extends up to 2000 mm, which fully satisfies the spatial requirements for roller replacement across the entire conveyor system. In the path planning phase, an obstacle expansion model is constructed, and an improved Informed RRT* algorithm is implemented to generate collision-free trajectories, ensuring effective obstacle avoidance. To improve trajectory smoothness, path pruning and cubic B-spline interpolation are applied to refine the initial paths. For trajectory planning in joint space, quintic polynomial interpolation is employed, with boundary conditions set to ensure zero velocity and zero acceleration at both the start and end points, thereby guaranteeing smooth and stable motion of the robotic arm. Simulation results indicate that joint angles, angular velocities, and angular accelerations vary smoothly throughout the roller grasping process, without abrupt changes, and converge to zero at the beginning and end of the trajectory. End-effector trajectory tracking error analysis reveals positioning errors within 0.8 mm for side rollers and 3 mm for central rollers, well within acceptable engineering accuracy thresholds. This work provides a theoretical foundation and a practical implementation framework for advancing automation and intelligent operation in roller replacement tasks within coal mine belt conveyor systems.

Pu, Congyuan, Qian, Ke

Development of Electric Vehicle Oils with High Energy Efficiency and Cooling Performance by Applying Novel Friction Modifier

2026-01-5064

7/31/2026

Improving the efficiency of electric vehicle (EV) transmissions can help to extend the driving range of EVs, and the EV oil used in these transmissions plays an important role. In this study, in order to enhance energy efficiency, we examined the effects of lowering viscosity, traction, and friction in EV oil. While friction modifiers (FMs) have been widely used as friction reduction technologies in the field of tribology for many years, we previously developed a new FM that reduces friction in drive units. We found that a combination of lowering viscosity and using the developed FM was effective for better energy efficiency. The oil formulated with the developed FM improved efficiency by approximately +0.8% to +0.9% compared to commercial EV oil. EV oil also requires cooling performance. We assumed that reducing heat generation through friction reduction would improve cooling performance and examined the effect of lowering viscosity, traction, and friction. Consequently, it was found that a combination of lowering traction and applying the developed FM is effective for reduction in parasitic heat losses. We also examined durability, which is an issue when reducing viscosity. The results suggested that the oil formulated with the developed FM had good durability for gears and bearings. Thus, we succeeded in developing an ultra-low-viscosity EV oil that has excellent energy efficiency and high cooling performance.

Nakamura, Toshitaka, Furuse, Takashi, Hasegawa, Shinji, Akahori, Shinya, Itou, Kimikazu, Sakurada, Soichiro, Akiguchi, Junnosuke

Application of a Novel Noise-Reduction Material to Reduce Squeak Noise in Automotive Instrument Panels

2026-01-5065

7/31/2026

In recent years, driven by increasing consumer demands for vehicle aesthetics and perceived quality, automotive instrument panels (IPs) have extensively adopted materials with poor friction compatibility, such as chrome-plated strips and synthetic leather. Concurrently, the engineering requirement for tighter matching gaps between components has significantly escalated the risk of friction noise. Traditional mitigation strategies—such as material substitution, increasing gap clearances, or applying physical isolation—are often difficult to implement due to design constraints, rendering the IP a critical high-risk zone for abnormal noise. This paper proposes a methodology to mitigate squeak noise between polycarbonate/acrylonitrile butadiene styrene (PC/ABS) and its mating counterparts by modifying the viscoelastic characteristics of the PC/ABS base material through the addition of a specialized polymer. Furthermore, a neural network model was established to objectively determine the noise compatibility of these materials. Evaluations of the material compatibility before and after modification demonstrate that adding a specific proportion of the special polymer to PC/ABS significantly improves its friction compatibility with materials such as polyvinyl chloride (PVC) skin. The efficacy of this solution was confirmed through application and verification in a mass-production vehicle.

Liu, Zubin, Cao, Chunyu, Hou, Hangsheng

Research on the Topology Design of Electric Vehicle Corner Module Suspension Based on POC Theory

2026-99-0151

7/31/2026

The corner module is an innovative design that combines drive, steering, suspension, and other vehicle structures into a single wheel unit. This achieves a high level of integration for chassis functions. A chassis built on this module can perform more complex movements. Suspension is a key part that decides how the vehicle moves. However, current suspension design approaches lack a systematic methodology for configuration synthesis and analytical verification for the multi-degree-of-freedom (multi-DOF) requirements of the corner module. This study introduces a new method for designing the corner module suspension based on the Position and Orientation Characteristic theory (POC theory). First, the type of suspension DOF is derived from chassis functional requirements by treating the required corner module motion as the target suspension DOF. Then, we decide the number of chains, links, and joints in the mechanism and perform configuration synthesis of suspension mechanism. Next, we combine the selected kinematic pairs and select suspension mechanisms that meet the requirements of suspension DOF. There are two steps of calculation in this process. In this study, the goal is to design a suspension with three links, two loops, and two degrees of freedom. Seven suspension mechanisms with specific loops and components were obtained using the proposed process. Finally, the paper presents the process of mechanism verification. Using the steering link and ground excitation as inputs, theoretical calculations and simulation analysis were conducted to verify that the mechanisms obtained meets the suspension design objectives. This proves that the POC theory-based method for creating multi-DOF suspension is effective.

Kong, Wenkai, Zhu, Wenfeng, Zeng, Zhixuan

Robotic Grinding Trajectory Planning and Correction Method for Large-Scale Complex-Shaped Products

2026-99-0227

7/31/2026

Due to the inherent characteristics of large dimensions, complex curved surfaces, and densely distributed protrusions present in aerospace products, conventional offline programming and trajectory planning techniques for robots primarily prioritize the facilitation of uninterrupted grinding processes and the generation of points along trajectories on surfaces characterized by smoothness. However, these methods encounter challenges in identifying and proactively avoiding surface protrusions during the planning phase. The present paper puts forth a proposal for an automated robot trajectory planning method for grinding operations. This method is predicated on the integration of region partitioning and deformation correction. Specifically, this method first identifies protrusions based on curvature features and rule matching, followed by an analysis of the feasible workspace of a six-axis industrial robot equipped with an external axis. The product surface is discretized into multiple regional units according to the distribution characteristics of protrusions and the constraints of the feasible workspace. Subsequently, a parameter-optimized parallel sectioning method is employed to independently plan trajectories for each unit. The utilization of on-site measured point cloud data facilitates the analysis of contour deviations. In addition, grinding trajectories are dynamically corrected to meet high-precision process requirements. This approach effectively overcomes the challenge that trajectory planning for large-scale, complex-shaped products is easily affected by protrusions. According to the established methodology, the development of an offline programming software system for robotic automatic grinding was initiated. To this end, experiments were conducted on aircraft wall panels to plan and modify grinding trajectories using the proposed method. This process was undertaken to validate the effectiveness and engineering practicability of the proposed method.

Fan, Changhao, Wang, Mingyang, Lv, Ruiqiang, Zhou, Peng

Design and Verification of Underactuated Coupled-Commutation Omnidirectional Mobile Integrated Camping Robot Chassis

2026-99-0820

7/30/2026

To solve the poor mobility of traditional camping vehicle chassis in complex terrains and confined spaces, this paper proposes an underactuated omnidirectional mobile chassis for outdoor camping vehicles. The chassis adopts a coupled commutation mechanism (double-crank elastic special-shaped connecting rods cross sliders), allowing each wheel to realize two motion modes (omnidirectional translation, in-situ rotation) with just one drive motor, reducing system complexity and cost. A control system based on the RoboMaster Development Board C Type integrates PID angle-loop control and motor speed-current dual closed-loop control for motion stability. Kinematic models for these two modes are established to derive the wheel parameter-chassis motion relationship. MATLAB R2023b-ADAMS 2024 co-simulations show the chassis maintains attitude stability under S-shaped curve, circular curve, and in-situ rotation; Qualisys 3D motion capture experiments confirm its stable attitude in omnidirectional movement.

Ren, Yulong, Lu, Zhiguo, Yang, Dongsheng, Wu, Di, Zhang, Tianyu, Qian, Zhenxin

Analysis and Optimization of Braking Deviation for Commercial Vehicles Based on ADAMS

2026-99-0802

7/30/2026

Given the braking deviation of commercial vehicles, this paper discusses the influencing factors and uses Adams simulation software to accurately model the vehicle model due to the unreasonable match between the suspension system and the steering system. Through K&C analysis and dynamics analysis of the model, the root cause of braking deviation is identified, and the simulation method is used to quickly realize optimization and verification.

Yan, Tang, Wang, Jingxian, Sun, Hongyang, Wu, Zhen

Nonlinear and Robust SDRE–H∞ Control for Brake-by-Wire under Variable Friction and μ-split

2026-36-0342

7/30/2026

This paper proposes a nonlinear and robust State-Dependent Riccati Equation (SDRE) combined with H∞ control architecture for brake- by-wire systems, specifically designed to handle severe tire-road friction variations and μ-split scenarios. The primary objective is to maximize deceleration capabilities while rigorously maintaining yaw stability, trajectory tracking, and passenger comfort through jerk limitation. Situated within the domain of active safety, this research addresses robustness against real-world uncertainties by utilizing a high-fidelity 14-degree-of-freedom vehicle model that accounts for longitudinal, lateral, and yaw dynamics, suspension-induced pitch and roll effects, and nonlinear tire behavior with explicit load transfer. To ensure near-optimal slip tracking under variable surface conditions, the system employs online friction estimation via Extended and Unscented Kalman Filters (EKF/UKF) fusing wheel and IMU data to adaptively adjust slip targets. The control strategy is bifurcated: the SDRE component manages dominant nonlinearities through state-dependent gains to prevent wheel lock-up, while the H∞ component provides robust disturbance rejection against parametric uncertainties such as mass variations and sensor noise. Control efforts are distributed via a Quadratic Programming (QP) torque allocator featuring anti-windup mechanisms and explicit saturation handling to compensate for lateral drift during μ-split braking. Validation is conducted through a Model- in-the-Loop (MIL) to Software-in-the-Loop (SIL) pipeline using scenarios including wet surfaces and panic braking. Simulation results demonstrate enhanced yaw stability and controlled deceleration profiles compared to conventional baselines, ensuring computational feasibility for automotive Electronic Control Units (ECUs).

Cubillos, Ximena Celia Méndez

Impacts of Automation and Electrification Trends on Pneumatic Braking Systems of Commercial Vehicles

2026-36-0341

7/30/2026

Historically, the demand for advanced technology, efficiency, and safety has been a primary driving force in the evolution of commercial vehicles, particularly with respect to braking systems. More recently, the increasing levels of vehicle autonomy and electrification have emerged as irreversible trends, significantly accelerating the development of new functionalities and innovative electrical/electronic [E/E] architectures. These advancements are essentially focused on performance optimization, risk mitigation, and enhanced system reliability through the application of functional safety and cybersecurity standards, thereby shaping the current landscape of braking system design. From an efficiency standpoint, braking systems with higher levels of electronic content, functional integration – included with regenerative braking systems - and harmonization have been developed to improve energy efficiency and support global scalability. Concurrently, new system configurations are continuously being introduced to enhance vehicle safety and advanced driver assistance capabilities, in alignment with evolving regulatory requirements and market expectations. This paper evaluates the impacts of automation and electrification on commercial vehicle pneumatic braking systems, focusing on Anti-lock Braking Systems [ABS], Electronic Braking Systems [EBS] and air management platforms. It provides a technical overview of both architectures, assessing their capabilities to meet modern requirements such as integration with advanced vehicle architecture, regenerative braking for electrified applications, and Advanced Driver-Assistance Systems [ADAS] support. The study details the evolution of air management systems, with emphasis on electrified vehicles, including key functions such as air compressor charge control, Air Processing Unit [APU] desiccant regeneration, and electronic control strategies. Additionally, it examines key drivers of braking system evolution, braking system selection considering ADAS regulatory developments, Net Zero strategies, and automation trends. The paper further evaluates compliance with functional safety and cybersecurity standards and assesses the readiness of both platforms for emerging mobility concepts. Finally, it highlights the risks of deploying higher levels of autonomy in heavy-duty towing vehicles when operating with non- ABS semi-trailers, identifying this as a critical area for further investigation.

Guarenghi, Vinícius Mendes, Nicora, Fabio, Pizzi, Rafael Fortuna, Resende, Angelo Roberto Rodrigues, Pinto, Gustavo Laranjeira

Development and Validation of a Braking Simulation Model Applied to a 6x2 Vehicle in Compliance with NBR 10966-2

2026-36-0318

7/30/2026

This study presents a comparative analysis of the braking performance of a heavy commercial vehicle under in-gear and out-of- gear conditions, combining experimental tests conducted at 60 km/h with high-fidelity computational simulation. The numerical model incorporates real engine torque, power, and motoring/braking curves, full brake system parameters, dynamic load transfer, tire–road friction characteristics, and ABS actuation. Simulation results were validated against experimental MFDD and stopping distance measurements. The simulation demonstrated a high correlation with the experimental MFDD values (5.3 vs. 5.36 m/s2 in the in-gear condition and 5.6 vs. 5.37 m/s2 in the out-of-gear condition), confirming the robustness of the model. Differences in stopping distance were attributed primarily to the real-world behavior of the ABS and to variability in the road surface friction coefficient. The study concludes that braking with the vehicle in gear provides improved longitudinal stability due to the resistive contribution of engine drag torque, which also reduces the thermal load on the service brakes. Overall, the results reinforce the essential role of simulation as a development, optimization, and certification tool for brake systems.

Junior, Getulio Soares, Canale, Antônio Carlos, de Oliveira, Sergio Henrique Fidelis, Pizzi, Rafael Fortuna

Influence of Wheel Stiffness on Brake Drum Deformation in Commercial Vehicles

2026-36-0309

7/30/2026

This study investigates the influence of wheel structural stiffness and wheel configuration (single- and dual-tire) on brake drum deformation in commercial vehicles equipped with pneumatically actuated drum brakes. A comprehensive multi-method approach was adopted, combining on-vehicle measurements, controlled bench testing using two- and three-dimensional optical metrology, and Finite Element Analysis (FEA) of the rear axle assembly. Three- wheel configurations were evaluated: a dual-tire arrangement (Configuration A) and two single-tire designs with distinct stiffness characteristics (Configurations B and C). Radial distortion was quantified using the displacement difference between the bottom and top regions of the brake drum (ΔZ). The results demonstrate that wheel stiffness and the offset between the wheel-disc attachment point and the ground reaction force are dominant factors governing brake drum deformation. The brake drum equipped with dual-tire configurations exhibited minimal ΔZ, whereas the brake drums equipped with single-tire configurations, particularly the least stiff Configuration C, showed pronounced outward radial displacement and increased deformation asymmetry. Design evaluations conducted under the worst-case configuration confirmed these findings, showing an effective reduction in brake drum deformation achieved by increasing the brake drum collar thickness (–36.1%; +6 kg) and by increasing the wheel rim thickness (–27.8%; +4.5 kg).

de Souza, Cassio Belo Clemente, Santana, Flávio Arcanjo, Henze, Steffen, Pulju, Hendrik, Filho, William Manjud Maluf

Factors that Influence the Determination of Adhesion Utilization of the ABS in Commercial Vehicles: A Case Study

2026-36-0307

7/30/2026

The anti-lock braking system (ABS) plays a fundamental role in preventing wheel lockup and preserving vehicle steerability and stability during braking. In Brazil, ABS is mandatory for commercial vehicles since 2014, following CONTRAN Resolution 380/11, with the objective of improving traffic safety and reducing road accidents. The performance of an ABS is directly influenced by the characteristics of the vehicle’s braking system, including its pneumatic architecture and mechanical component sizing, which determine brake-force distribution and the frequency of ABS intervention. Regardless of these characteristics, developers must ensure that ABS efficiency complies with applicable regulatory requirements. For performance assessment, NBR 10966 Part 6 establishes procedures for measuring and calculating the adhesion utilization of ABS. Represented by the letter epsilon (ε), adhesion utilization quantifies the relationship between the braking performance achieved with ABS active and that corresponding to the vehicle’s maximum braking capacity without wheel slip. This metric provides an indirect evaluation of system efficiency. This work presents a case study conducted during the development of the ABS for a medium-heavy truck equipped with more than two axles. The study consisted of the analysis of results obtained following the adhesion utilization determination methodology defined in NBR 10966 Part 6, and of the evaluation of its applicability to multi-axle vehicles. Despite the braking system and vehicle configuration meeting all minimum static and dynamic performance requirements, the measured adhesion utilization fell below expectations. This outcome prompted a detailed investigation of both the measurement approach used for this vehicle category and the factors affecting the tire–road friction coefficient, which are independent of the braking system itself. The analysis indicated potential improvements in the test methodology for vehicles with more than two axles and highlighted the significant influence of test-track surface conditions on the results obtained.

Dias, Eduardo Miranda, Rudek, Claudemir, Travaglia, Carlos Abílio Passos

Development of an Electronic Braking System Applied to Commercial Vehicles Focused on Improvement of Braking Pedal Feeling and Braking Performance

2026-36-0308

7/30/2026

Embedded electronics are becoming increasingly common in solutions developed for commercial vehicles. Technological advancements enabled the development of electronic solutions that provide braking systems with functions to improve safety, comfort, performance, durability, and cost-effectiveness of wear components. In this context, the electronic braking system, EBS, has become increasingly present in the electronic architecture of commercial vehicles. Considering the functions that can be developed within the electronic braking system, the following stand out: the pedal characterization, which potentially improves comfort and increases the sensation of safety during braking; and the brake force distribution, which can be adjusted to ensure that the vehicle achieves an optimal balance between performance and friction material’s durability. This work consists of the presentation of tests and results of technical activities required to develop an EBS for medium-heavy and heavy-duty vehicles designed for a variety of applications. EBS was developed to prioritize comfort and safety, with optimized braking sensation and performance without compromising the durability of the wear components of the vehicles. Activities started with the experimental determination of the brake factor—a value that transmits to EBS the braking capacity of the truck. In sequence, brake pedal setup was performed based on data extracted from a vehicle equipped with a mechanical braking system and validated by subjective assessment. In addition, the braking force distribution definition started by establishing its target: friction material’s wear equalization or braking performance; went through balancing the mechanical braking power per axle; and finished being validated by data obtained from vehicles in use. Results showed that the implementation of electronic braking systems in commercial vehicles brought several benefits to the product, in particular, improvement of braking feeling when pressing the brake pedal, and in both braking performance and friction material’s durability, which resulted in a better balance between maintenance costs and technical advantages.

Travaglia, Carlos A. P., Rodrigues, André, Rudek, Claudemir, Dias, Eduardo Miranda, Silveira, Juliana

Feasibility of CFD-thermal-structural simulation based on real braking tests

2026-36-0331

7/30/2026

During the development of mechanical components, engineers use numerical tools as a first step to design, develop, and analyze potential solutions for specific requirements, thereby reducing time- to-market of new components. Furthermore, numerical tools are also highly useful for analyzing components that exhibit failures. For brake discs, numerical analysis must consider not only mechanical behavior but also thermal and fluid dynamic behavior. In this context, as a further step, experimental tests can be performed in test facilities such as dynamometers, where the brake discs are evaluated under different operating conditions to determine their susceptibility to failures such as thermal distortion, judder (hot or cold), squeal, coning, etc. If such failures occur, corrective actions can be implemented using different approaches: a) redesign of the disc and braking system aided by numerical tools; b) tuning of the matching between disc and pad materials; and c) modification of the disc and/or the pad material. Regarding the first approach, the finite element method (FEM) is one of the most important numerical tools, and to obtain reliable results, accurate boundary conditions must be applied. The aim of the study is to demonstrate the feasibility of the CFD-thermal-structural boundary conditions derived from an experimental test performed on a ventilated brake disc assembled in an instrumented vehicle. Firstly, a comparison between an analytical method and the CFD solution was made regarding convective heat transfer coefficient (HTC). The test consisted of 16 main braking cycles from 140 to 0 km/h, conducted under eight different pedal pressure levels. After each main braking, a thermal shock was applied to the disc using water, followed by a secondary braking from 80 to 0 km/h, always with the same pedal pressure. The numerical analysis results showed good agreement with experimental tests in terms of temperature distribution. In addition, axial displacement distribution along the circumference is presented, with emphasis on coning deformation, one of the main triggers for judder.

Bagatini, Pablo Schettert, Viotti, Matias Roberto, Pereira, Leonardo, Tuzzin, Matheus, Titton, Angelo Pradella, Boaretto, Joel, De Leon, Daniel Milbrath

Influence of Aero Enablers on Brake Cooling Performance

2026-36-0317

7/30/2026

Amid growing society concerns about environmental sustainability, fuel consumption has become a key factor in mitigating greenhouse gas emissions. As a result, modern vehicle design increasingly prioritizes aerodynamic drag reduction. However, aerodynamic enhancements can significantly affect brake cooling, since airflow distribution plays a crucial role in braking performance. This study explores the interplay between underbody aerodynamic features and brake cooling efficiency in production vehicles. Three body styles—compact sedan, midsize SUV, and minivan—were evaluated to determine how varying aerodynamic configurations influence airflow around the wheel assemblies. The findings highlight critical trade-offs between aerodynamic optimization and thermal management, offering valuable insights for achieving balanced vehicle development strategies.

Batista, Lorena, Motta, Daniel, Seren, Ericson, Bergel, André, Sarmento, Alisson, Terra, Rafael

PSO-Optimized LQR Control for Anti-Sway and Positioning of Rotary Cranes

2026-99-0860

7/30/2026

This paper proposes a Linear Quadratic Regulator (LQR) parameter optimization method based on Particle Swarm Optimization (PSO) to enhance the grab attitude controller for rotary crane systems, with the objectives of improving positioning accuracy and suppressing load swing. Lagrange’s equations are first used to create a nonlinear dynamic model of the rotary crane, which is then linearized around an operational point to produce a fourth-order state-space representation. Based on this representation, a dual-objective fitness function is created, employing the Integral of Time multiplied by Absolute Error (ITAE) as the performance index and assigning the swing angle error more weight. The important parameters of the LQR weight matrix are optimized using the PSO algorithm. A dedicated novel pre-compensation gain algorithm is then developed to solve the pseudo-inverse of an augmented matrix, thereby removing steady-state error. According to simulation results, the PSO-optimized controller greatly improves the anti-sway performance and positioning accuracy of the system by reducing the peak swing angle and settling time by 33.9% and 55.9%, respectively, as compared to the traditional LQR control.

Yao, Yulei, Xiang, Yang

Innovative Friction Modifier for Copper-Free Brake Pad Applications

2026-36-0313

7/30/2026

The development of copper-free brake pads poses a significant challenge because copper plays a critical role in tribofilm formation and friction stability. This study proposes a novel approach using a recycled flake iron oxide material, characterized by high thermal stability and a unique plate-like morphology, as a sustainable alternative. The material acts as a friction modifier, promoting the formation of stable tribofilms and serving either as a copper substitute or a functional additive. Its iron-oxide composition ensures strong compatibility with the counterface tribofilm, enhancing adhesive friction, while its role as a primary plateau contributes to friction stability and reduced wear. Three application scenarios were investigated: (i) copper substitution in Low-Steel (LS) and Non-Asbestos Organic (NAO) formulations, (ii) partial replacement of steel fibers in copper-free LS formulations, and (iii) synergistic use with iron sulfide in copper-free NAO formulations. Tribological performance was evaluated using a tribometer, and worn surfaces were analyzed by SEM and EDS to characterize tribofilm formation. Results demonstrate that the proposed material provides friction stability and wear resistance comparable to copper in both LS and NAO formulations. Partial substitution of steel fibers improved wear resistance by up to 75%, while synergistic addition with iron sulfide further enhanced friction and wear performance in copper-free NAO pads. These findings highlight the potential of this recycled material as a sustainable and effective alternative for copper-free brake pads, offering both environmental benefits and high tribological performance while reducing reliance on critical raw materials.

Jara, Diego Chávez, Lorenzana, Carlos

Design of a Jamming Test Apparatus for Aircraft Cargo Door Latches

2026-99-0833

7/30/2026

The reliability verification of cargo door latches for civil aircraft requires a safe, accurate, and controlled method for simulating jamming failures in lab settings. We adopt a crank-rocker mechanism with a variable degree of freedom (DOF) to construct a novel jamming apparatus that may be dynamically constrained in order to meet this requirement. The apparatus maintains two DOFs when not in use, which permits the latch mechanism to move freely. Both the guiding shafts and the rotation shafts are simultaneously constrained for a jamming test, reducing the mechanism’s DOFs to zero. This operation creates a precise and passive lock that immobilizes the mechanism without the need for an active external load. This approach offers a more realistic simulation of the sudden jamming brought on by wear, foreign object intrusion, or manufacturing tolerances. A theoretical kinematic analysis is then conducted to calculate the mobility of the mechanism and determine the theoretical conditions and transition paths to reach the two functional states. Moreover, the apparatus implements a real-time computational model based on classical planar linkage force analysis and integrates a multi-sensor system. This model converts sensor data into the torques and jamming forces that are actually delivered to the latch. The findings demonstrate that the proposed design accurately simulates latch jamming conditions while allowing for real-time monitoring and quantification of important dynamic characteristics. Thus, by offering a dependable and effective verification solution for cargo door latches, the apparatus greatly improves testing safety and the value of the data gathered.

Ren, Jie, Zeng, Xiaohu, Qiu, Xudong, Xie, Youshui

Research on the Design Technology of Anti-Roll Attachment for Seaplanes

2026-99-0803

7/30/2026

This paper takes a seaplane as the research object, based on the roll damping commonly used in the field of ships, to carry out the applicability analysis and design technology research of the roll damping for the seaplane. A T-tail configuration was selected as the attachment. The design process involved sequentially selecting the horizontal stabilizer airfoil, designing the aspect ratio parameters, and determining the strut airfoil. Consequently, two T-tail design schemes with aspect ratios of 0.76 and 1.53 were proposed. Through the hydrodynamic performance analysis of the T-tail design installed on the seaplane, the advantages and disadvantages of the two T-tail designs in the wave environment are studied. The results demonstrate that the aspect ratio of the T-tail’s horizontal stabilizer directly affects the seaplane’s wave-induced motion response. The proposed design with a larger aspect ratio of 1.53 significantly reduces wave resistance and motion response across various conditions. In the case of a relatively small aspect ratio, the maximum pitching motion is reduced by 38.4%, and the maximum heave is reduced by 59%.

Jiang, Ting, Pi, Xufeng, He, Chao, Wen, Changqing, Li, Xu

Theoretical Influence of Load Distribution on ADAS Performance in Commercial Vehicles

2026-36-0339

7/30/2026

Advanced Driver Assistance Systems (ADAS) are increasingly integrated into heavy-duty commercial vehicles to improve road safety, mitigate accident severity, and enhance operational efficiency. In the context of braking systems, however, a significant gap remains between system calibration practices and real-world operating conditions, where most evaluations and validations of ADAS and braking performance are conducted under nominal or standardized load assumptions, which fail to represent the wide variability of payload magnitude and distribution typically observed in trucks, semi- trailers, and buses. Variations in vehicle mass and load distribution directly affect braking efficiency, axle load transfer, center of gravity (CG) position, and stability limits, posing critical challenges to both conventional brake systems and brake-related assistance functions. This paper presents an exploratory qualitative study based on a systematic literature review addressing the influence of variable loading on braking performance and the operation of ADAS in commercial vehicles. Scientific publications, experimental investigations, and technical reports from both academia and industry were thoroughly analyzed, with emphasis on service brake efficiency, load-dependent braking behavior, rollover propensity, and the performance of the ADAS systems. The reviewed studies demonstrate that longitudinal, lateral, and vertical CG displacements significantly modify braking force distribution, actuator effectiveness, and stopping distances, particularly under emergency braking and downhill driving conditions. Improper load distribution was consistently associated with reduced braking margins and increased instability risk. The findings further indicate that integrating load-aware strategies into braking control and ADAS calibration can improve braking consistency, reduce component stress, and enhance overall vehicle safety. As a contribution, this work emphasizes the need to incorporate variable load conditions into braking system evaluation, ADAS development, and certification procedures for heavy commercial vehicles, ensuring robust and reliable performance under real operating conditions.

Rubbo, Bruno Tiago, Dacol, Franco De Bastiani, Do Nascimento, Vagner

Maximizing Autonomy, Minimizing Environmental Impact: The Cooperative Regenerative Braking

2026-36-0316

7/30/2026

In conventional braking systems, the kinetic energy of a vehicle is predominantly converted into heat through friction, a thermodynamically inefficient process. This not only causes progressive wear of components but also leads to the release of various materials, including heavy metals and organic compounds. With increasing concern over non-exhaust emissions, the search for innovative solutions becomes imperative. In electrified vehicles (xEVs), regenerative braking emerges as a strategic technology, converting kinetic energy into electrical energy to recharge the battery and extend range. This process not only enhances the vehicle's energy efficiency but also results in reduced frequency and intensity of mechanical brake usage. Consequently, there is a direct reduction in the wear of friction braking components, which translates into a significant mitigation of particulate matter emissions associated with this wear. The optimization of these systems occurs through Cooperative Regenerative Braking (CRB), which intelligently integrates with hydraulic braking. The primary challenge lies in managing the transition between modes to recover maximum energy without compromising safety and driver comfort. This technical paper explores how CRB employs 'torque blending' via advanced ECUs and software to adjust in real-time the proportion of each braking type, aiming for maximum energy recovery in diverse driving scenarios. To verify the effectiveness of this system, practical tests were conducted on a vehicle. The results obtained from these tests were conclusive, demonstrating significant gains in energy efficiency, with an increased battery recharging capacity during decelerations, optimized by the braking system. This improvement in efficiency directly impacts the reduction in the use of the conventional friction brake system and, consequently, a sharp decrease in particulate matter emissions. In this context, the intelligent and cooperative management of regenerative braking is a strategic and fundamental component for building a more sustainable future in vehicular mobility.

Batagini, Emerson, Romão, Bruno

Research on Model State Machine-Based Simulation and Validation of Civil Aircraft Ground Deceleration Functional Architecture

2026-99-0834

7/30/2026

The implementation of the ground deceleration function in civil aircraft represents a critically complex process that deeply relies on the seamless collaboration of multiple onboard systems, including but not limited to braking, thrust reversal, spoiler, and steering systems. The operational logic governing these systems is highly intricate, characterized by tightly coupled interactions, stringent safety requirements, and a vast array of diverse physical and logical interfaces. This inherent complexity makes it exceptionally difficult to gain a thorough, system-level understanding of the implementation mechanisms and collaborative principles solely through traditional means of examining extensive, yet often fragmented, design documentation. The limitations of document-based analysis frequently lead to unforeseen integration conflicts, which are typically discovered late in the development cycle, resulting in substantial rework costs and project delays. To address this pervasive industry challenge, this paper selects the aircraft ground deceleration function as a representative case study and proposes an innovative, simulation-based validation methodology. This approach systematically utilizes model state machines to create a dynamic digital representation of the system-of-systems, enabling rigorous validation of aircraft deceleration requirements under various operational scenarios. By adopting this model-based systems engineering (MBSE) paradigm for mechanism representation, our approach effectively captures the nuanced coordination, timing dependencies, and dynamic interactions within the multi-system operational logic. It thereby facilitates the intuitive identification, analysis, and resolution of potential design flaws, including logical conflicts, deadlocks, race conditions, and uncovered or ambiguous requirements. Consequently, the method not only provides a robust framework for validating the aircraft’s function-related design requirements with greater confidence but also offers crucial, data-driven support for the iterative optimization and evolution of the overall functional architecture. The fundamental value proposition of this research lies in its transformative capability to convert implicit design knowledge and assumptions—originally scattered across voluminous documents, specifications, and expert minds—into an integrated set of executable, observable, and analyzable formal models. This digital thread enables systems engineers and designers to identify deep-seated integration and coordination issues proactively during the early conceptual and detailed design stages, rather than relying on discovery during the late, costly integration and testing phases. By shifting validation left in the development V-cycle, this approach significantly reduces the risk of major design changes and associated cost overruns later in the project lifecycle. Ultimately, it effectively enhances the overall maturity, safety, certifiability, and operational reliability of complex aircraft function development, paving the way for more efficient and predictable engineering processes.

Wang, Mingqian, Yu, Qiao, Yu, Miao, Tang, Chao

Influence of Roll Gap Control under Acceleration Conditions

2026-99-0867

7/30/2026

During the cold rolling process, when the rolling speed enters the acceleration stage, the rolling force often exhibits a linear decline accompanied by fluctuations. This leads to a decrease in the uniformity of steel strip thickness distribution, resulting in the failure of the outgoing strip to meet quality requirements in terms of shape and thickness. In this paper, a three-dimensional model of a six-high rolling mill is established using Abaqus, and the influence of gap control during the acceleration stage on strip shape is systematically investigated. By analyzing the relationship between rolling force and roll gap variations, a gap compensation strategy based on a dynamic stiffness model is proposed. Simulation results demonstrate that implementing gap compensation during the acceleration stage effectively improves the consistency of strip thickness, with significant reductions in both thickness range and standard deviation.

Tang, Yingxin, Yan, Zhuwen, Cao, Wenjun, Wu, Jiawei

Research on the Performance Evaluation Method of Intelligent Chassis Vehicles Based on AHP

2026-99-0861

7/30/2026

The comprehensive performance evaluation system for intelligent chassis vehicles comprises multi-level indicators and exhibits certain complexity. In this study, the Analytic Hierarchy Process (AHP) is employed to calculate the weights of indicators across different performance levels. Comprehensive performance is evaluated through the integration of objective indicator assessment and subjective scoring, and the evaluation results of the vehicle’s comprehensive performance are ultimately derived. This work provides a scientific scoring method for the product testing and evaluation of intelligent chassis vehicles.

Wu, Shiyu, Wang, Jingxian, Guo, Ruiling, Liang, Dong, Li, Saisai, Yu, Xuetian

Influence of Modified Fly Ash Content on the Properties of Resin-Based Friction Materials

2026-99-1657

7/24/2026

In this study, five resin-based brake pad samples with modified fly ash contents of 0%, 4%, 8%, 12%, and 16% were prepared to investigate the influence of fly ash content on the comprehensive performance of the friction materials. The tribological properties of all samples were evaluated under temperature conditions ranging from 100 °C to 350 °C, and their overall performance was assessed using five evaluation indices. Based on the AHP-MOORA algorithm, sample F12 exhibited the highest comprehensive weighted score of 0.11, followed by samples F0 and F8 with scores of 0.10 and 0.09, respectively, indicating a slight decline. In contrast, the comprehensive weighted scores of F4 and F16 were relatively low, at 0.05 and −0.01, respectively. Among the five composites, F12 demonstrated the best overall performance, with F0 and F8 ranking next, while F4 and F16 performed poorly. These results suggest that, within a certain range, increasing the fly ash content can enhance the comprehensive properties of the material. However, excessive addition of fly ash may lead to the detachment of harder particles during wear, thereby increasing wear thickness and wear rate.

Li, Xiaobiao, He, Kang, Zhao, Zhuanzhe, Wu, Bo, Sun, Fei

Remote Steering Control Systems

J2588_202607 (Current)

7/23/2026

This SAE Information Report establishes a uniform procedure for assuring the manufactured quality, installed utility, and performance of automotive remote steering controls other than those provided by the vehicle manufacturer (OEM). These products are intended to provide driving capability to persons with physical disabilities. The adaptive modifications seek to compensate for lost or reduced function in the extremities of the driver with a disability. Remote steering controls are designed to provide a steering input device alternative to the OEM steering wheel that either reduces the required input force, changes the required range of motion or changes the location of the steering control, or any combination of the above. These controls supplement by power, other than by the driver’s own muscular efforts, the force output of the driver with a disability. Because this is an Information Report, the numerical values for performance measurements presented in this report and in the accompanying Test Procedure, while based upon the best knowledge available at the time, have not been validated by a testing of the Test Procedure.

Adaptive Devices Standards Committee

Modal-Constrained Co-optimization Approach of Thermomechanical Performance and Weight for Straight-Ribbed Brake Discs Using Deep Learning

2026-01-5061

7/22/2026

In this study, an efficient method for concurrent thermomechanical performance and weight optimization under modal constraints is proposed to address the coupled design challenges of thermomechanical characteristics (thermal capacity, thermal deformation, and modal) and structural weight in straight-ribbed brake discs. Based on high-fidelity computer-aided engineering (CAE) simulations of brake disc thermomechanical behavior, a neural network (NN)-based surrogate model and a ResNet-guided geometric feature recognition (RGFG) model for automatic modality recognition were developed, and integrated with a particle swarm optimization (PSO) framework for optimal solution exploration. When applied to a passenger vehicle brake disc case study, the surrogate model of NN demonstrates remarkable accuracy: it shows more than 95% agreement with the CAE results in thermal capacity prediction, the prediction accuracy of thermal deformation exceeds 90% compared to CAE results and 83.4% compared to test result, thereby validating the method’s effectiveness. Compared with conventional CAE approaches, the surrogate model of NN achieves a subsecond prediction speed, significantly reducing computational costs. The surrogate model of RGFG achieves a test accuracy exceeding 95%. Furthermore, the proposed optimization framework offers valuable insights for the inverse design of brake discs.

Han, Simiao, Jiang, Daxin, Han, Chao, Wang, Jinda, Sui, Qinghai

Optimization Design of Automotive Handling Stability Based on ADAMS Insight

2026-99-1801

7/17/2026

This paper systematically optimizes and validates the handling stability of a vehicle using ADAMS/Car software based on vehicle data provided by a car manufacturer. A comprehensive vehicle dynamics model was established, including a body model, an anti-roll bar model, a powertrain model, a steering subsystem model, and a full vehicle model, with a focus on optimizing suspension parameters such as toe angle and camber angle. Validation was carried out using simulation test methods such as dual-wheel synchronous excitation, steering returnability, and angle step input. The results show significant improvements in the vehicle’s yaw rate, steering force, and torque after optimization, with particular excellence in steering return time and transient response. Additionally, steady-state cornering simulation results indicate that the optimized vehicle has improved body roll stiffness and lateral compliance, with increased understeer, further enhancing stability and response speed during steering. The findings of this study improve the handling stability and safety of vehicles and provide valuable references for future automotive design.

Li, Diannuo, Zhu, Jiale, Wang, Dongmei, Wei, Yi, Huang, Yuanyuan, Ban, Lu

Research on Quadrotor Trajectory Tracking Based on Model Predictive Control

2026-99-1850

7/17/2026

Quadrotors (UAVs) are widely used in intelligent inspection, environmental monitoring, and logistics due to their simple structure, strong maneuverability, and vertical take-off and landing capabilities. However, their highly nonlinear, strongly coupled, and highly constrained dynamic characteristics make trajectory tracking control a challenging task. To improve trajectory tracking accuracy and control robustness, this paper proposes a quadrotor trajectory tracking method based on model predictive control (MPC). First, a six-degree-of-freedom dynamic model of the quadrotor is established and linearized with small disturbances to transform it into a state-space model suitable for MPC design. An MPC optimization controller is then constructed, with an objective function that minimizes state error and imposes an input energy penalty, while explicitly considering the system's input and state constraints. Simulation results demonstrate that this method exhibits good tracking accuracy and control smoothness for typical trajectory tracking tasks (such as circular and spiral trajectory tracking). Compared with traditional PID and LQR controllers, the proposed method significantly improves maximum error, mean square error, and interference rejection. This study provides an engineering-feasible optimization control framework for UAV trajectory control.

Peng, Fei, Tao, Zhong, Gao, Qiang, Jia, Bobo

UAV Path Planning Method for Urban-Mountain Mixed Environments Based on Improved Divine Religions Algorithm

2026-99-1840

7/17/2026

This paper, for the first time, applies the Divine Religions Algorithm (DRA) to three-dimensional UAV path planning. Targeting the complex terrain of urban-mountain mixed environments, we propose a novel method that incorporates multiple enhancements, including A* initialization, single-point disturbance mutation, and adaptive weighting. First, the A* algorithm is employed to generate high-quality initial paths, serving as the skeleton of the population. Innovative mechanisms such as terrain-adaptive disturbances and dynamic weight adjustment are integrated to achieve both efficiency and robustness in path optimization. Comparative experiments with Genetic Algorithm (GA) and Crowned Porcupine Optimization (CPO) show that the improved DRA algorithm exhibits significant advantages in terms of path length, safety margin, average altitude variation, average turning angle, and overall cost function. It consistently obtains superior paths and achieves faster convergence. The results demonstrate that the proposed approach provides an efficient, adaptive, and practical intelligent optimization tool for UAV path planning in urban-mountain mixed or similarly complex environments, offering promising prospects for engineering applications.

Fang, Lianyu, Yi, Wenjun

Research on Convergence Analysis of Multi Objective Optimization Algorithm for Lightweight Bus Chassis Architecture

2026-99-1842

7/17/2026

The multi-objective optimization algorithm framework for lightweight bus chassis architecture selects new sample points by utilizing the optimal solution obtained during the iterative process, and then reshapes the dynamic Kriging surrogate model, ultimately achieving the implementation of multi-objective optimization for lightweight bus chassis architecture. Its core lies in whether the NM-MOPSO algorithm can accurately converge to the global optimal solution of the model. This determines the accuracy of the sampling area and the effectiveness of the new sample points. If the algorithm converges inaccurately, it will result in poor performance of the model in the optimal solution region, thereby affecting the accuracy of the solution. Therefore, the precise convergence of NM-MOPSO algorithm is crucial for the success of multi-objective optimization algorithm for lightweight bus chassis architecture.

Han, Yangqi, Hu, Jing, Chen, Yajuan, Hu, Guangxue

Analysis of Structural Stiffness Indicators of Manned Lunar Vehicles

2026-99-1827

7/17/2026

The structural stiffness of a manned lunar vehicle is a core indicator ensuring its stable operation in the complex lunar environment. The vehicle’s body structure must meet multiple requirements, including high stiffness, lightweight design, and adaptability to lunar surface conditions. Since lunar gravity is only 1/6 of Earth’s and the terrain is rugged and dusty, the body structure must employ a high-stiffness design to withstand driving impacts and resist deformation, thereby preventing mechanical failures or safety hazards for crew members caused by excessive structural distortion. However, excessive structural stiffness would result in an overweight vehicle body, conflicting with the spacecraft’s lightweight requirements. Thus, the structural stiffness index should be optimized to a lower value while ensuring safe operation during lunar surface driving without compromising performance. This paper calculates and determines the structural bending and torsional stiffness indicators for the manned lunar vehicle’s body through simplified model calculation and the FEA method.

Shen, Zhenghui, Wu, Yingjia, Yang, Jianfeng, Wang, Weijun, Zhang, Chongfeng, Han, Liangliang

Modeling and Damping Optimization Design of Commercial Vehicle Cab Air Suspension System

2026-99-1862

7/17/2026

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.

Li, Saisai, Yang, Chang, Guo, Ruiling, Zhang, Zhongyuan, Liang, Dong, Wu, Shiyu

Effect of Aftermarket Suspension Modifications on ADAS Functionality of Five Light Vehicles

12-09-04-0031

7/15/2026

Advanced Driver Assistance Systems (ADAS) are increasingly prevalent in light vehicles, both in the United States and worldwide. Moreover, ADAS are steadily being incorporated into regulatory requirements globally. Like ADAS, the automotive aftermarket is also increasing in size and significance. As both ADAS and the aftermarket industry are growing, the effect of aftermarket modifications on ADAS functionality should be examined. However, there is very little information available in the public domain about the effect of aftermarket modifications on original equipment ADAS. This work is centered on a considerable research project that was conducted to address the knowledge gap at the intersection of ADAS and the aftermarket. The project investigates five light vehicles that are important to the aftermarket, including four pickup trucks and one sport-utility vehicle. It focuses solely on the effect of popular aftermarket suspension modifications, and it does not evaluate aftermarket ADAS equipment. Typical suspension modifications were applied to the test vehicles in five modification categories, including stock, lower kits, level kits, 3–4 in. lift kits, and 6 in. lift kits. Six ADAS test procedures were performed for the test vehicles, comprised of blind spot detection, crash imminent braking, lane departure warning, pedestrian automatic emergency braking, rear cross traffic alert, and traffic jam assist. The physical tests were developed based on National Highway Traffic Safety Administration (NHTSA) New Car Assessment Program (NCAP) written experimental procedures. Statistical hypothesis testing was performed for the purpose of determining if average measured dynamic responses varied in the modified vehicles compared to stock. The results show that vehicles modified with typical aftermarket modifications will likely retain their ADAS functionality, given the limitations of the small sample size of five vehicles. Vehicles with 6 in. lift kits are expected to exhibit greater variability in their dynamic responses compared to stock. Plans for future work and unanswered research questions are outlined, with the goal of advancing aftermarket ADAS integration and ensuring the safety and performance of modified vehicles.

Bastiaan, Jennifer M., Morales, Luis, Muller, Mike

Reverse Automatic Emergency Braking (AEB) Testing Summary

J3339_202607 (Current)

7/14/2026

This SAE Information Report provides a broad summary of existing Reverse Automatic Emergency Braking test protocols to help assess whether additional test protocols are needed. Eventually, the task force may develop additional protocols to support testing of Reverse Automatic Emergency Braking systems.

Active Safety and Driver Support Systems Standards Committee

On Disturbance-Aware Minimum-Time Trajectory Planning: Evidence from Tests on a Dynamic Driving Simulator

10-10-03-0026

7/13/2026

This work aims to investigate how disturbance-aware, robustness-embedding reference trajectories translate into actual driving performance when executed by professional drivers in a dynamic driving simulator. The study compares three planned reference trajectories against a free-driving baseline (NO-REF) to assess the trade-offs between lap time (LT) performance and steering effort: NOM, the nominal time-optimal trajectory; TLC, a track-limit-robust, time-optimal trajectory obtained by tightening margins to the track edges; and FLC, a friction-limit-robust, time-optimal trajectory obtained by tightening against axle/tire saturation. All reference trajectories share the same minimum LT objective with a small steering-smoothness regularizer, and are evaluated with two professional drivers driving a high-performance car on a virtual track. The reference trajectories stem from a disturbance-aware minimum-LT framework recently proposed by some of the authors, where worst-case disturbance growth is propagated over a finite horizon and used to tighten tire-friction and track-limit constraints, preserving performance while delivering probabilistic safety margins. LT and steering energy (SE) are evaluated as indicators of driving performance and steering effort, respectively, while RMS values of lateral deviation, speed error, and drift angle are used to characterize driving style. The results reveal a Pareto-like trade-off between LT and SE: NOM achieves the shortest LT, but with the highest SE, TLC minimizes SE at the expense of longer LT, while FLC lies near the efficient frontier, markedly reducing SE relative to NOM with only a minor LT increase. Removing reference trajectories (NO-REF) leads to both higher SE and longer LT, confirming that trajectory guidance improves pace and control efficiency. Overall, the findings highlight reference-based and disturbance-aware planning, particularly the FLC variant, as effective tools for training and for achieving fast yet stable trajectories.

Masoni, Matteo, Palermo, Vincenzo, Gabiccini, Marco, Gulisano, Martino, Previati, Giorgio, Gobbi, Massimiliano, Comolli, Francesco, Mastinu, Gianpiero, Guiggiani, Massimo

Simulation Analysis and Optimization Design of Rim Clamping Mechanism

2026-99-0533

7/10/2026

According to the working characteristics of the tire changer, the movement characteristics of its rim clamping mechanism are analyzed, and the complex movement structure is abstracted and simplified into four identical six-bar mechanism subunits. One of the subunits is taken as the research object, and the mathematical model of kinematic analysis is established. Using MATLAB software to simulate and analyze the motion law of each component, the mechanical characteristics of the component are analyzed. The optimization of the design parameters of the “six-bar mechanism subunit” is realized, the rim clamping mechanism becomes more stable, and the clamping force follows the diameter of the rim more closely.

Zhao, Fengqin, Zhou, Liyao, Wang, Mantong, Huo, Fengwei

Path Planning Algorithm for Self-Driving Cars Based on High-Precision Maps and Improved A*

2026-99-0588

7/10/2026

To address the limitations of the traditional A* algorithm in lane-level navigation, we propose an autonomous vehicle path planning algorithm based on high-precision maps and an improved A* algorithm to ensure effective application in complex traffic environments. We construct a hierarchical high-precision map based on the Lanelet2 framework to achieve structured modeling of complex road environments. To address the adaptability issues of the A* algorithm in lane-level navigation, we propose optimization schemes, including heuristic function improvements, path segment division, and target point validity verification, to ensure that vehicles can autonomously change lanes on multi-lane roads. By combining dynamic programming (DP) and quadratic programming (QP), we ensure the safety and smoothness of the path. Simulation results demonstrate that the optimized algorithm enables smooth stopping and starting at traffic lights in structured road environments and autonomous lane changes on multi-lane roads. Compared to using DP alone, QP provides smoother and safer driving paths and exhibits superior obstacle avoidance performance in speed planning. This method effectively ensures the rationality of path planning in complex road environments while strictly adhering to traffic rules, thereby enhancing the safety and reliability of path planning.

Wang, Siyu, Zhou, Rong, Shi, Tian, Xu, Zhen, Zhao, Zhiguo

Enhancement of Tractive Trafficability for a Four-Track Unmanned Amphibious Tracked Vehicle

2026-99-0578

7/10/2026

This study addresses the insufficient tractive trafficability of four-track unmanned amphibious tracked vehicles (UATV) in beach terrain by proposing an optimization strategy based on coordinated suspension height and hitch point adjustment. A mathematical model of vehicle drawbar pull was established to systematically analyze the influence mechanisms of vertical load distribution, suspension adjustment, and hitch point elevation on tractive trafficability. DEM-MBD coupling simulations revealed differentiated traction laws under sandy loam and clay conditions, particularly regarding track overlap effects. Results demonstrate that in sandy loam, rear-axle traversal over front-axle tracks reduces drawbar pull due to soil loosening, whereas track overlap enhances drawbar pull in clay through soil compaction. Nine suspension-hitch configurations were tested, validating optimization strategies: increased front-axle loading (Configuration a) in sandy loam and reduced front-axle loading (Configuration f) in clay. These configurations significantly improved tractive trafficability.

Chen, Yaoyao, Gao, Xue, Wang, Wenhao, Xu, Xiaojun

A Review of UAV Support Technologies for Low-Altitude Airspace Operation and Management

2026-99-0597

7/10/2026

In recent years, with the low-altitude economy developing rapidly, the operation and management of low-altitude airspace has gradually become a hot topic. Unmanned aerial vehicles (UAVs) constitute a fundamental component of the low-altitude airspace ecosystem, significantly influencing its structure and functionality. The technological advancement of UAVs has fundamentally transformed the operational paradigm for low-altitude airspace management. This paper presents a comprehensive review of UAV-supported technologies in the context of low-altitude airspace operations and management. It systematically analyzes key technologies and applications of UAVs in areas such as airspace capacity and safety assessment, trajectory planning, and standardized flight management. Drawing from kinematic analysis and traffic flow theory, UAV density control and collision risk prediction offer quantitative insights into airspace capacity evaluation. Additionally, probabilistic analysis and simulation techniques enhance the accuracy and efficiency of safety assessments. In trajectory planning, multi-objective optimization algorithms tailored to operational scenarios—such as logistics delivery and agricultural operations—have significantly improved the utilization of airspace resources. Concurrently, collision avoidance techniques leveraging graph search, numerical optimization, and machine learning ensure flight safety in complex environments. Standardized flight management relies on pilot qualification review, airworthiness certification, and planning standardization, while discussing airspace segmentation strategies based on geofencing and intelligent control systems. Future developments in UAV-supported technologies are expected to trend toward higher precision, intelligence, and regulatory integration. By incorporating cutting-edge fields such as deep reinforcement learning and digital integration, these technologies are poised to further enhance the efficiency and safety of low-altitude airspace management, thereby providing robust technical support for the sustainable growth of the low-altitude economy.

Gong, Lei, Ma, Zhenxiao, Luo, Qin

Design and Testing of a Quasi-Zero-Stiffness Vehicle-Mounted Isolation System with Additional Inerter

2026-99-0520

7/10/2026

Vehicle vibrations during precision instrument transport can cause damage and failure. Existing vibration isolators often lack reliability, mass production feasibility, and easy maintenance. In this paper, we design and analyze a quasi-zero-stiffness vehicle-mounted isolator with an inerter, decreasing dynamic stiffness while raising the effective mass. Theoretical, simulation, and experimental results show improved isolation performance, lower isolation frequency, and a broader isolation bandwidth.

Li, Kai, Lv, Sibo, Sun, Ning, Dai, Shijie

Design and Analysis of Orthogonal Excitation Eddy Current Brake for High-Speed Trains

2026-99-0513

7/10/2026

As high-speed train technology advances, the demands on braking system performance have intensified. Known for their efficiency, reliability, and eco-friendliness, Linear Eddy Current Brakes (LECB) have become a focal point in the research and development of high-speed train braking systems. This paper presents an innovative Orthogonal Excitation Eddy Current Brake (OEECB), which enhances the braking force without modifying the overall dimensions of the conventional LECB. By adding a set of longitudinal excitation coils parallel to the rail surface, the OEECB creates an orthogonal excitation structure that augments the braking force. Initially, this paper outlines the design concept of the OEECB and then analyzes its working principle based on electromagnetic field theory. Subsequently, a finite element solver is employed to numerically model the electromagnetic characteristics of the OEECB. Finally, by comparing the performance differences between the conventional LECB and OEECB, the superiority of the OEECB in enhancing braking performance is demonstrated. The results indicate that under the same excitation current conditions, the OEECB increases the braking force by over 20 % while maintaining a controllable increase in attractive force.

Huang, Liuwen, Zuo, Jianyong, Zhang, Yu

Research on the Influence of Suspension Characteristics on Ride Quality of Railway Wagon

2026-99-0511

7/10/2026

With the country’s economy and people’s consumption capacity increasing, railroad transportation tasks have become more and more frequent, and it is growing the demand for the transportation of high-value goods, fresh produce, etc. Compared with traditional Freight vehicles, express freight vehicles have great advantages in terms of carrying capacity, mobility, and transportation cost, but when it run at a speed of 160 km/h, it often occurs that failure of axle-box rubber springs, primary vertical dampers, secondary lateral dampers, anti-yaw dampers, and air springs. How to ensure the safety and stability of the train under suspension system failure conditions is a problem that needs to be solved during the design process. In this paper, through multi-body system dynamics software, a nonlinear dynamics model of lateral and vertical coupling of the vehicle system is established to analyze the influence of suspension system failure on the stability of 160 km/h express freight vehicles. The analysis results show lowering the operating speeds can meet the Ride Quality of the Vehicles in special conditions.

Gao, Zhixiong, Ma, Kai, Xiao, Yanmei, Chen, Weidong, Wei, Xiao, Sha, Chengyu, Bian, Huihui

Research on Low-Altitude Economic Air Traffic Control Model Based on Spatiotemporal Constraint Reinforcement Learning

2026-99-0580

7/10/2026

With the rapid development of the low-altitude economy—represented by drone logistics, aerial inspections, and air taxis—air traffic has exhibited new characteristics including diverse forms, high density, and significant speed differences. To address these changes, the traditional air traffic control system requires upgrades, particularly in dynamic aircraft scheduling. This study proposes an air traffic control model (DS-ATM) tailored to this domain, built on the Deepseek large model. By integrating spatiotemporal graph neural networks with multi-objective reinforcement learning algorithms, the model achieves real-time path planning and conflict resolution in complex airspace environments. Validated using public datasets such as OpenSky Network, NASA UTM Dataset, and METAR meteorological data, experimental results demonstrate its significant advantages in reducing conflict rates and scheduling delays.

Li, Rui, Zhao, Fangyu, She, Yue, Li, Wujie

Fifteen Instrumented Motorcycle Crash Tests into a Barrier and Stiffness Comparison of Standard and Upside-Down Forks

2026-01-5059

7/10/2026

Fifteen instrumented crash tests were performed using a 2005 Yamaha R6 motorcycle. Seven tests were performed with upside-down (USD) forks and eight tests were performed with standard forks. The 2005 Yamaha R6 provided a platform where both types of front forks could be interchanged. For all tests, the motorcycle was delivered into a concrete block at speeds varying between 5 and 23 mph. Seven tests were conducted at low speeds to determine the onset of permanent deformation. Eight tests were conducted at higher speeds to observe the wheelbase reduction of the motorcycle and its relationship to impact speed. This paper summarizes the data from these tests related to wheelbase reduction, impact dynamics, and post-impact movement, allowing comparison between two different suspension systems and historical datasets.

Lucernoni, Anthony, Boyd, Dusty, Wahba, Ronny, Taeuber, Andre, Stoner, Jacob, Law, Trevor

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