Browse Topic: Chassis

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Global–Regional Energy Balance Climate Modeling Framework for Country-Level Temperature Projections Based on CO₂ Radiative Forcing2026-24-0021To be published on 09/21/2026
This study presents a computational framework for estimating country-level temperature projections based on global radiative forcing from CO₂ emissions. The methodology integrates a carbon-cycle accumulation module, a logarithmic radiative forcing formulation, and a dynamic one-box energy balance model (EBM) to simulate global mean temperature evolution. Atmospheric CO₂ concentration is computed from cumulative global emissions using an airborne fraction parameter. Radiative forcing is then determined using the established logarithmic relationship between concentration and forcing. The global temperature response is calculated dynamically by solving the transient energy balance equation, incorporating effective heat capacity and climate sensitivity parameters. To regionalize projections without relying on high-resolution General Circulation Models (GCMs), an empirical regional amplification factor is introduced. This coefficient is derived from historical regression between observed
Gutierrez, Marcos, Taco, Diana, Sampietro-Saquicela, Jose, Bermudez-Herrera, Leandro
Structural Robustness and Regime-Dependent Uncertainty in a Reduced-Order Physics Model for Vehicle Fuel Consumption Using Monte Carlo Analysis2026-24-0015To be published on 09/21/2026
Accurate prediction of vehicle fuel consumption typically relies either on simplified empirical correlations or on high-fidelity simulations that are computationally expensive. However, the structural robustness of reduced-order physics-based models under parametric uncertainty has not been systematically quantified. In particular, the interaction between model simplifications and uncertainty in vehicle and fuel properties across different operating regimes remains insufficiently investigated. This study presents a reduced-order physics-based framework derived from fundamental force and energy balances to estimate fuel consumption in L/100 km. The model includes aerodynamic drag, rolling resistance, inertial effects, drivetrain efficiency, and fuel lower heating value. Unlike purely empirical formulations, the proposed structure preserves physical interpretability while remaining computationally efficient. Monte Carlo simulations are employed to propagate simultaneous uncertainties in
Gutierrez, Marcos, Taco, Diana
Characterisation of Brake Wear PM2.5 and PN10 Emissions Across Pad/Disc Technologies, Vehicle Types and Braking Behaviours, Under Real World Conditions2026-24-0022To be published on 09/21/2026
This paper summarises targeted brake emissions investigations undertaken as part of the Department for Transport’s Non Exhaust Emissions programme. The work was carried out to improve understanding of particulate mass and particle number emissions from friction braking and to assess the influence of component selection, vehicle technology, operating conditions, and control measures on those emissions. Starting from a pre-developed brake enclosure and sampling system methodology, these were further refined to improve airflow management, reduce leakage, and minimise sampling artefacts. The updated system was integrated with a suite of particulate measurement instruments, including MPEC (hot and cold), APC10, DMS500, and eFilter, enabling simultaneous measurement of volatile and non volatile PN10 plus PM2.5. A matrix of nine brake pad formulations and two disc types was tested on a common C segment vehicle platform across chassis dyno and on road cycles, together with controlled braking
Andersson, Jon
Understanding Tyre Wear Particle Emissions: Volatile Dominance, Variability, Coarse Particles and Measurement System Development for Chassis Dynamometer Use2026-24-0018To be published on 09/21/2026
This paper presents a set of targeted tyre emissions studies carried out within the Department for Transport’s Non Exhaust Emissions programme. The work was directed at improving the measurement of airborne particles generated by tyres, and at examining the factors that influence particle number and particle mass emission, plus explored physical tread wear. To achieve this, a revised sampling duct system was developed with high extraction flow and partial wrap-around of the tyre, and a coarse hard-wearing surface was applied to the chassis dyno roller. The sampling system supplied Total PN4, PN10 (volatile and non volatile), PM2.5, and particle size instrumentation. Multiple tyre types were selected to represent a broad range of sizes, constructions, manufacturers, compounds, and mileages. Tests were performed on a dedicated tyre testing facility using PG42, WLTC, and RDE based cycles, together with additional cycles designed to investigate the influence of temperature, speed, and
Andersson, Jon, Campbell, Michael, de Vries, Simon, Kramer, Louisa, Marshall, Ian, Southgate, Jason, Waite, Gary
Simulation-Based Development and Evaluation of Heat-Quantity-Based Thermal Operating Strategies for Automotive Applications2026-24-0012To be published on 09/21/2026
Efficient and robust thermal management is a key prerequisite for reproducible vehicle testing and energy-efficient powertrain operation. Conventional thermal operating strategies are commonly based on temperature setpoints and often neglect the dynamic relationship between heat input, system inertia and transient operating conditions, leading to increased energy demand and limited reproducibility under highly dynamic driving cycles. This paper presents a simulation-based development and evaluation of a heat-quantity-based thermal operating strategy for automotive applications. Instead of controlling the system solely via temperature targets, the proposed approach utilizes accumulated and instantaneous heat input as central decision variables for thermal control, explicitly accounting for thermal system dynamics. The investigation is conducted using a detailed vehicle simulation model including a physically-based thermal system representation. An innovative decentralized thermal
Stenger, Erik, Fiore, Luis, Weimer, Niko, Beidl, Christian
Component Dynamics of a Motorcycle Brake Caliper: Analysis and Experimental Validation of Seal-Groove Mechanics and Controlled Rollback Design.2026-01-0823To be published on 09/14/2026
Pad - Rotor separation is critical to effective braking performance, pedal feel and NVH. In floating brake calipers, this separation is primarily governed by the seal and groove mechanics. Current studies primarily focus on the mechanics through empirical methods on single seal-groove systems for car calipers. However, a significant literature gap exists for motorcycle seal grooves and any system that utilizes a two seal-groove system with a primary pressure seal and a secondary dust seal. Since 75% of automobiles registered in India are motorcycles and Anti-lock braking becoming mandatory from 2026, designing a caliper with precise seal-groove mechanics becomes critical. This study proposes a theoretical framework by modeling the seals as a shear-beam and predicting the rollback using stick-slip hysteresis and resistive forces of the piston. Experimental validation was performed on three production motorcycle calipers, with the measured rollback and the piston push following the
Vaitheeswaran, Gyaneshwar, N, Manoj, M, Mahesh, Yogesh, Deepak, Rai, Ashutosh
Machine Learning Prediction of Wear of NAO Brake Pad Using Scaled-Down FMVSS 135 Testing2026-01-0808To be published on 09/14/2026
Brake pad lifespan significantly influences environmental pollution and public health due to non-exhaust particulate emissions. Global vehicle production reached approximately 7 billion units in 2025, with brake systems generating an estimated 50,000 to 100,000 metric tons of wear debris annually, underscoring the need for improved durability and material optimization. This study investigates the capability of a Fully Connected Neural Network (FCNN) to predict brake pad wear and support formulation optimization. Controlled experiments were performed using a simplified FMVSS 135 protocol on a Universal Mechanical Tester (UMT) to simulate realistic braking conditions. Wear loss was measured under varying normal loads, sliding velocities, and interface temperatures. An FCNN was selected for its ability to capture nonlinear interactions between operating conditions and tribological responses. Despite a limited but high-quality dataset, the application of data standardization
Katakam, Abhishek, Eslamiat, Hossein, Kancharla, Sai Krishna, Filip, Peter
Optimization of Hydraulic Disc Brake Caliper Parameters to Achieve Near Zero Residual Drag in Two-Wheeler Brake Systems2026-01-0820To be published on 09/14/2026
Residual drag in hydraulic disc brake systems is an inherent phenomenon caused by elastic deformation of piston seals, geometric tolerances, and frictional interaction between piston, seal, and brake pads. Even minimal unintended pad-to-disc contact after brake release can generate residual torque, leading to increased rolling resistance, temperature rise, accelerated pad wear, and reduced vehicle efficiency. With growing emphasis on performance optimization and energy efficiency in two-wheeler applications, minimizing brake drag without affecting braking response has become an important design objective. This paper presents the design, analysis, and experimental validation of a zero-drag floating brake caliper concept developed to reduce residual brake torque through optimization of piston seal characteristics and groove geometry. The study focuses on understanding piston rollback behavior as the primary mechanism governing pad clearance after pressure release. Analytical evaluation
Badade, Ashish Laxman
Architecting Safety-Critical Systems for AI-Enabled Software-Defined Vehicles: A Compute, Timing, and Isolation Framework with a Brake System Case Study2026-01-0811To be published on 09/14/2026
Software-defined vehicle (SDV) platforms are reshaping safety-critical system design by consolidating braking and other motion-control functions on centralized heterogeneous edge compute that also executes physical-AI workloads. This consolidation breaks traditional assumptions of fixed ECUs and simple timing envelopes, complicating assurance of determinism, isolation, and fail-operational behavior for ASIL-D brake functions. Building on a decentralized brake-by-wire (BbW) architecture with dual controllers, redundant low-voltage power grids, and smart electromechanical brake corner actuators, this paper proposes a systems-level framework for architecting safety-critical functions in AI-enabled SDVs along three dimensions: compute, timing, and isolation. The framework classifies conventional and AI-based functions and maps them to heterogeneous compute classes; defines architectural patterns that combine safety islands, power-domain redundancy, and hardware partitioning to support
srinivasaraghavan, soumyasudharsan
Influence of Scrub Radius on Steering Dynamics, Bearing Durability and Wheel-End Packaging in Heavy Commercial Vehicles2026-01-0831To be published on 09/14/2026
Front axle geometry is a critical determinant of vehicle performance in heavy commercial vehicles (HCVs), directly influencing steering feel, component life, and maintenance costs. This paper investigates the effects of increasing scrub radius—defined as the lateral distance between the tire contact patch center and the steering axis intersection with the ground—on steering dynamics, durability, and packaging. A larger kingpin offset generating a positive scrub radius improves steering leverage and reduces steering torque, particularly beneficial for power-assisted steering systems. However, its broader implications for wheel-end design require detailed evaluation. High-fidelity multi-body dynamics models, validated through instrumented vehicle testing, were employed to quantify these effects under diverse scenarios, including low-speed maneuvering, high-speed lane changes, and severe braking. Results indicate that a controlled increase in scrub radius (10–20 mm) reduces steering
Pandiyan, Mahendran, Saxena, Saurabh
Assessing brake wear particle emissions and performance characteristic of NAO-ceramic formulation for Euro 7 Compliance2026-01-0828To be published on 09/14/2026
EU7 regulation has focused on non-exhaust emission from brake and tire wear and has set the brake particle emission limits accordingly. The current PM10 limit is set at 7 mg/km for IC vehicles and 3 mg/km for EV (electric/battery vehicles) of M1, N1 category. Hence, the brake particle emissions test should be conducted according to the UN Global Technical Regulation No. 24 (GTR-24) procedure on the brake inertia dynamometer. Due to these new requirements; brake systems need to be homologated with regard to EU7 emissions limits. In this study, NAO-ceramic formulation is developed and tested for performance, wear, noise and brake emission on brake inertia dyno using the global standards such as SAE J2522 (AK-Master Performance), SAE J2707B (Block Wear Test), SAE J2521 (NVH) and, Emission Test (WLTP/GTR-24. The developed NAO-ceramic friction grade not only having better friction, wear and NVH properties, but also reduce the brake emissions substantially and meets the current PM10 limit
Kumar, Mukesh, Tomar, Bharat, Ali, Sharafat, Kalel, Navnath
Thermomechanical Fatigue Life Prediction of Lamellar Graphite Cast Iron Brake Disks Using Advanced Material Models and Elastic-Plastic Fracture Mechanics2026-01-0816To be published on 09/14/2026
A comprehensive thermomechanical fatigue (TMF) life prediction methodology is developed for cast iron brake disks. The approach employs transient temperature fields as thermal loads in a nonlinear structural finite-element analysis (FEA). To obtain reliable stress and strain histories for cast iron, a time- and temperature-dependent plasticity model is required that captures viscous effects, nonlinear kinematic hardening, and tension–compression asymmetry. For this purpose, a unified elasto-viscoplastic Chaboche constitutive model coupled with damage is developed and implemented as a user material subroutine (UMAT) in the general-purpose FEA software Abaqus by Dassault Systèmes. In addition, a mechanism-based short-crack TMF model is extended to three-dimensional stress states under transient non-proportional loading conditions for TMF life prediction. The material parameters of the constitutive and the damage models are identified for lamellar graphite cast iron using isothermal and
Lee, Heewook, Garcia, Arnoldo, Liu, Yi, Hazime, Radwan, Boughanmi, Heni, Kassir, Abdallah
Comparison of the Surfaces and Coefficients of Friction of Truck Brake Pads Tested on a Flywheel Test Bench and a Scaled Tester – A Case Study2026-01-0826To be published on 09/14/2026
Mechanical brakes have been used and studied in many areas of mechanical engineering and automotive technology for decades. However, the processes in the contact zone have not yet been described with sufficient accuracy. One reason for this is the inability to observe the contact zone during contact. Studies in which one contact partner is replaced by an optically transparent material influence the processes in the contact area. Researchers are therefore forced to examine the surfaces of the contact partners after the actual contact has taken place. Various measuring systems, such as microscopes or laser sensors for surface structure measurement, are used to measure the surfaces of the brake pads. Due to shorter measuring times, mainly only smaller samples from measurements using pin-on-disc tribometers are examined for this purpose. However, various studies show that the friction and wear values of pin-on-disc tribometers cannot be transferred to real brake systems. For this reason
Rosenthal, Tobias Richard, Wiest, Daniel Christian, Meyer, Henning Jürgen
Data to Decisions: An AI-Driven Test Intelligence Platform for Integrated Analysis of Raw Data, Test Reports, and Specification Compliance in Brake System Validation2026-01-0807To be published on 09/14/2026
Validation of brake systems is increasing in complexity due to electrification, software-defined architecture, integrated control modules, and higher functional safety requirements. Although physical testing remains the primary source of engineering evidence, interpretation of results including DVP&R/PVP&R compliance verification, anomaly detection, documentation, and milestone decision support continues to rely heavily on manual engineering analysis. This results in extended feedback cycles, inconsistent interpretation across teams, and limited traceability between raw data, reports, and governing specifications. To support engineers with more objective validation processes, there is a growing need for structured, data-driven intelligence that transforms dispersed test artifacts into actionable engineering decisions. This paper presents Data to Decisions, an AI-driven Test Intelligence Platform designed for integrated analysis of raw measurement data, test reports, validation plans
Divakaruni, Saikiran, Willey, Joseph, Srivastava, Namrata, Sankar, Arya, Namala, Divya, Gowtham, Rahul Sangani
Advanced Brake Force Distribution on trailers with Bendix Electronic Brake Controller2026-01-0797To be published on 09/14/2026
Commercial vehicle fleets frequently operate with tractors that connect to different trailers and dollies, resulting in combinations with varying brake pad wear across wheel‑ends. Traditional brake force distribution strategies whether proportioned, electronic, or load‑adaptive do not account for these pad life differences. This can lead to uneven brake utilization, irregular maintenance intervals, and increased total cost of ownership (TCO), especially in mixed‑fleet and multi‑trailer operations. This work introduces an advanced brake force distribution function, a mechatronic brake control concept that incorporates brake pad health information into supervisory brake force allocation. In the proposed architecture, the tractor is equipped with a Brake Control ECU, which collects brake pad life status from each trailer or dolly through Pad Wear Sensing ECUs over the Tractor‑Trailer CAN (TT‑CAN) network. The Pad Wear Sensing ECUs report pad wear information only and do not host braking
Ganesha, Vinodkumar
Further Investigation of Brake Squeal: Effect of (Inboard/Outboard) Pads Property Differential2026-01-0799To be published on 09/14/2026
It was reported earlier that the wear differential between the inboard pad and the outboard pad leads to brake squeal generation. The (I/O) pads wear differential can occur due to hardware issues such as brake pad drag and/or two different wear rates of the (I/O) pads, which is caused by two different properties of the pads although the pad formula may be the same. The current investigation focuses on the pad property issues. It is found that pad compressibility differential and pad hardness differential are closely related to brake squeal generation. The property differentials are caused by pad porosity variations. The implications of hardness differential on friction/vibration will be discussed.
Liu, Richard, Wu, Shane, Wu, Godot, Li, Aihong, Zou, Tianlang
Correlation of tribological characteristics with Brake Emission Factors in automotive disc brakes2026-01-0829To be published on 09/14/2026
Following the recent introduction of the Euro 7 regulations, research on non-exhaust emissions, including brake wear particles, has increased. However, full-scale dynamometer tests are affected by complex variables such as vehicle class and brake system specifications, which makes it difficult to analyze the unique characteristics of friction materials independently. Previous studies have predominantly focused on comparing emission levels by friction material composition or on disc surface treatments, and quantitative correlations, resolved by friction material type, between the physical wear mass of friction materials and the Brake Emission Factor (BEF), remain scarce. In this study, the brake emissions from various friction materials were precisely measured using a scale dynamometer reflecting the UN-GTR No. 24 standards. By applying the WLTP cycle, a quantitative correlation was derived between the friction characteristics and the BEF for each braking section. The results show that
Jang, Pan Gyu, Kim, Duck Hyeon, Jeong, Yoon Oh, Kwon, Sung-Wook, Jung, Kwang Ki, Lee, Jungju
Time-Series Friction Torque Prediction for Drum Brake Systems via Mixed-Effects Random Forest Framework2026-01-0809To be published on 09/14/2026
The application of drum brake systems is expanding due to increasing cost competitiveness requirements in EV and purpose-built vehicle markets, as well as the introduction of EURO-7 particulate emission regulations. In spite of this trend, drum brake friction behavior is not yet fully understood because it is governed by complex and strongly coupled complicating mechanisms, including temperature history, braking conditions, and interactions between drum brake components. To address this gap, this study presents a method for developing a time-series friction torque prediction model using the Mixed-effects Random Forest (MERF) machine learning framework. Time-series data collected from sensors during drum brake dynamometer tests were analyzed to identify the key variables that govern the friction torque. Significant inputs were selected through Exploratory Data Analysis (EDA), considering test-to-test variability and potential mixed effects, and were then used to train and tune the MERF
Yoon, Jungro, Cho, Sunghyun, Kim, Wonjoon
Influence of Caliper Piston Wall Thickness and Hard Anodizing on Thermal Transfer and Seal Rollback Stability in Hydraulic Disc Brakes2026-01-0822To be published on 09/14/2026
Thermal stability and sealing reliability are critical performance parameters in hydraulic disc brake systems, especially under high-energy braking conditions where elevated temperatures directly influence brake fluid behavior and elastomer seal durability. Lightweight design trends increasingly encourage reduction in caliper piston wall thickness to optimize mass and response characteristics; however, such modifications alter the thermal conduction path and transient heat distribution within the piston–seal interface. This study investigates the combined effect of 50% reduction in aluminum caliper piston wall thickness and increase in hard anodizing thickness from 20 µm to 50 µm on heat transfer characteristics and piston seal rollback consistency. A comparative analytical and experimental approach is adopted to evaluate thermal resistance changes due to variation in anodic oxide layer thickness and piston geometry. One-dimensional thermal modeling is correlated with controlled
Badade, Ashish Laxman
Design considerations for optimizing the wheel bearing outer ring bolt‑mounting pattern for reduced drag2026-01-0830To be published on 09/14/2026
Electric vehicles (EVs) place unique and demanding requirements on wheel bearing systems due to their increased vehicle mass, higher torque output, and the need for improved energy efficiency to maximize driving range. These factors elevate the loads transmitted through the bearing‐to‐knuckle joint, often necessitating higher clamp loads to maintain joint integrity. However, increased clamp loads can amplify wheel bearing outer ring distortion, leading to higher rotational drag and reduced bearing durability. Managing and minimizing outer ring distortion is therefore critical for EV wheel bearing design, as well as for high‑performance vehicles that experience extreme lateral loads at the hub‑to‑knuckle interface. This paper investigates key design considerations for optimizing the wheel bearing outer ring and its mounting interface to minimize distortion under elevated clamp loads. A comprehensive CAE‑based Design of Experiments (DOE) is conducted to evaluate the influence of various
Mandhadi, Chaitanya Reddy, Lee, Seungpyo, Bovee, Benjamin, Callaghan, Kevin
Cast-In Brake Disc – An affordable lightweight design for passenger car brake discs2026-01-0821To be published on 09/14/2026
To meet evolving automotive demands, Fritz Winter is developing new lightweight brake discs. While alternatives to traditional cast iron discs exist, aluminum compound versions are too costly, and mechanically joined steel hat discs present complex assembly and tolerancing challenges. Fritz Winter’s engineering objective was to create a reliable method for joining a steel hat with a cast iron friction ring directly during the production process. This composite design significantly reduces vehicle weight, without compromising durability, comfort, or NVH performance. The methodology involves inserting a finished, stamped steel hat (2.5 to 3 mm thick) into the casting mold and then casting the friction ring directly onto it. This process eliminates the need for subsequent machining of the hat. During development, several key challenges were overcome. A patent-pending sealing process was created to prevent liquid iron from spilling onto the steel hat. To ensure a strong bond and prevent
von Reth, Thomas
Study on the Friction Characteristics of Disc Brakes with Ceramic Surfaces for High Performance Vehicle2026-01-0827To be published on 09/14/2026
In this study, various methods were reviewed to simultaneously satisfy the high-temperature braking performance required for high-performance vehicles and the brake dust criteria by environmental regulations. Among them, the characteristics of two types of Brake disc with ceramic composite surfaces were evaluated to prevent disc wear even under the condition of using metallic friction materials with excellent fade performance. As a result of the evaluation, carbon ceramic disc without metal-to-metal contact during braking showed superior characteristics compared to hard metal cladding disc.
Kim, Yoon Cheol, yeongwoo, cho, KIM, YOUNGMIN
Precise Simulation and Test Closed-Loop Verification of Drag Torque for Brake Caliper of In-Wheel Electric Motor2026-01-0813To be published on 09/14/2026
Aiming at the industrial pain points of high control difficulty of drag torque, low precision of traditional simulation and lack of authoritative test closed-loop verification for the special brake caliper of in-wheel electric motor, taking the YF3501S73 front brake caliper and YF3502S73 rear brake caliper as the research objects, a high-precision finite element simulation method coupling the nonlinearity of piston seal material with bilateral parallel return springs was proposed, and the simulation boundary conditions were calibrated by finely matching the bench test working conditions. To ensure the authority and engineering practicability of the research results, the drag torque bench test was carried out in strict accordance with QC/T 592-2013 Performance Requirements and Bench Test Methods for Hydraulic Brake Caliper Assemblies, and in alignment with the international brake drag test specifications of SAE J2923 and JASO C448, thus realizing a complete closed loop of simulation
Liu, Yuqi
Finite Element–Based Wear Analysis of Brake Pads2026-01-0817To be published on 09/14/2026
Brake pads are essential components that play a critical role in ensuring vehicle safety and braking performance. Variations in the pad–disc contact interface directly affect the behavior of both the disc and the piston, which can lead to reduced braking efficiency, unstable pedal response, or overall brake system degradation. As wear on the pad surface gradually alters the contact conditions, accurately predicting the evolution of brake pad wear is vital not only for maintaining brake stability but also for assessing long-term component durability. In particular wear behavior observed during the burnish evaluation mode is significant, as this phase governs the stabilization of the pad surface and influences the establishment of a steady friction coefficient. In this study, a finite element–based wear analysis procedure was developed using the Archard wear theory to evaluate the wear behavior of automotive brake pads. A wear direction algorithm and an element distortion control
SONG, SEONG IL, JOO, SANG DON, KIM, MIN SOCK, KERSZBERG, NICOLAS, Lee, Heewook
Physics-Informed Machine Learning Digital Twin of Electro-Mechanical Brakes for Clamp-Force and Friction Estimation2026-01-0806To be published on 09/14/2026
As the industry is rapidly moving towards dry-by-wire architectures, accurate Electro-Mechanical Brake (EMB) models are increasingly critical for safety-relevant force control, diagnostics, and consistent performance over temperature and lining wear. However, widely used EMB identification methods often rely on linearized models or 'characteristic curve' calibrations that struggle to generalize across operating regions where friction, hysteresis, and compliance are strongly non-linear and temperature sensitive. Prior EMB force-estimation literatures addressed pad contact detection, hysteresis and thermal compensated clamp-force estimation, yet practical accuracy gaps remain during transients and under changing friction signatures. This work proposes a digital twin based on Physics-Informed Neural Networks (PINNs) that preserves the EMB's governing dynamics while learning both (i) physically meaningful parameters- such as effective system inertia, damping, stiffness etc., and (ii) a
Rai, Prakhar, Gadhvi, Tirth
A Study on the Development of Brake Moan for CTBA Vehicles Using Simulation2026-01-0814To be published on 09/14/2026
Not only are customers' expectations for the development of various products, but also the demand for emotional quality improvement of the products is steadily increasing. Brake NVH, which is generated during vehicle braking, has a lot of influence on the emotional aspects of customers. There are several brake NVH such as judder, squeal, and moan. First, judder is phenomena of handle, brake pedal vibration and noise that occur during braking at the high-speed. The quality of judder has been improved a lot by applying judder detection and compensation logic in internal combustion engines and the heat load on the disc is reduced by regenerative braking in electric vehicles. So the judder problem hardly occurs these days. A squeal is a noise generated during braking at a low speed. The squeal is solved by tuning and shape change of a friction material in the high frequency band and by making the robust systems design such as caliper and disc in the low frequency band. Moan noise is low
KIM, SUNGHO, Kim, Jeongkyu, HWANG, JAEKEUN, Kang, Donghoon
Optimizing Brake Pedal Feel and Driver Comfort in Buses with Pneumatic Braking Systems2026-01-0804To be published on 09/14/2026
Abstract:- Brakes are a critical safety component in vehicles, and every parameter of the braking system plays a vital role in vehicle operation. Among these, brake pedal feel and driver confidence are key factors, in addition to achieving the required brake force, deceleration, and stopping distance. These aspects depend on the system-generated torque, available pneumatic pressure, lining material properties, and Electronic Braking System (EBS) parameters. This paper focuses on the factors influencing brake pedal feel while maintaining a balance between driver comfort and confidence during bus operation. Under optimal braking conditions, brake pedal response and brake torque gradient must align with the driver’s deceleration demands. The braking system must respond promptly, completing the application in the shortest possible duration. The brake torque gradient values specified in the EBS file should be neither too low nor too high, and the brake pedal feel must remain consistent
Pujari, Sachin Subhashrao, Karampurwala, Zoeb, RAJ, AMRITESH
Safe State Definition and Verification for Distributed Multi-Controller EMB Architectures2026-01-0800To be published on 09/14/2026
The Electro-Mechanical Brake (EMB) system is an essential technology for safe braking in modern vehicles. However, the adoption of multi-controller architectures has introduced new challenges to conventional Safe State strategies. Traditionally, the Safe State defined in functional safety means "function shutdown," and in accordance with ISO 26262 definition, aims for an "operational mode without risks exceeding reasonable levels." However, in the multi-controller architecture of EMB systems, the Fail-Operational Safe State concept is applied, where the system continues to provide limited functions even in the event of faults. It is essential to verify whether such operational modes actually satisfy the safety requirements of ISO 26262. This paper redefines the Safe State according to failure modes in EMB systems, analyzes system state transitions, and presents a coherence analysis methodology for validating the availability of resources required to provide limited functions in the
KIM, KANG SAN
Predicting Brake Squeal Occurrence Using Machine Learning with Temporal Feature Analysis of Braking-Torque Test Data2026-01-0812To be published on 09/14/2026
The automotive industry's paradigm shift toward autonomous driving and electrification has introduced new competitors threatening market dominance through differentiated value propositions. In this highly competitive landscape, delivering irreplaceable customer value requires providing sustainable and authentic luxury experiences. Quiet driving represents a tangible value that customers genuinely appreciate. Brake squeal—high-frequency noise arising from torque-induced friction behavior during braking—negatively impacts customer satisfaction and must be suppressed. Despite significant advances in brake squeal prediction modeling, the irregular nature of squeal generation mechanisms has prevented development of a generalized predictive model applicable to product development processes. Development and verification remain largely experimental. This limitation constrains early-phase design validation, as brake squeal is highly sensitive to chassis and braking system design. When squeal
Cho, Sunghyun, Yoon, Jungro, Kim, Yoon Cheol, Kim, Jeongkyu, KIM, SUNGHO, baek, SongYi, KIM, Won Joon, CHOI, KYUNG ROK
Aerodynamic Disc Brake Drag: An Elusive Source of Variability2026-01-0802To be published on 09/14/2026
The ever-present drive to increase vehicle range and efficiency has resulted in disc brake caliper requirements at or near zero residual drag. It is increasingly critical to understand and design around potential edge cases that can drastically increase off-brake drag. One frequently observed, but often misunderstood, phenomenon is drag induced by aerodynamic forces surrounding the brake pad. Complex airflow characteristics surrounding the pad in the brake corner environment can lead to Venturi Effect induced air pressure differentials on each side of the pad, leading to transient, yet pronounced, increases in brake drag. This paper will follow a case study during which brake pad pressure differentials were discovered and experimentally measured, review the Venturi Effect as it relates to brake corners, and explore modelling approaches for identifying and correcting designs that are prone to this phenomenon.
Robere, Matthew, Tresmondi, Thales
Influence of Ferritic Nitrocarburizing with Smart-ONC® on the Modal and Damping Behavior of Gray Cast Iron Brake Rotors2026-01-0798To be published on 09/14/2026
Ferritic nitrocarburizing (FNC) with Smart-ONC® post-oxidation has been developed as a production-capable surface engineering solution for gray cast iron (GCI) brake rotors to meet the Euro 7 non-exhaust particulate emission limits. While prior investigations have demonstrated significant PM₁₀ reduction, improved corrosion resistance, and stable braking performance, the influence of FNC on noise, vibration, and harshness (NVH) performance requires systematic evaluation. This study quantified the relative contributions of the alloy composition, rotor geometry, and FNC treatment to the modal frequency and damping behavior. Seven ventilated disc types from multiple foundries were characterized to assess the composition-driven variability. In addition, 120 production discs (ventilated and solid) were measured before and after FNC processing to isolate the treatment effects. Modal properties were obtained using impulse-hammer testing under free-free boundary conditions in accordance with
Awe, Samuel Ayowole, Holly, Mike, Winter, Karl-Michael
Electro-Hydraulic Brake-by-Wire and Off-the-Shelf ABS Integration: Control Design and Hardware in the Loop Validation2026-01-0795To be published on 09/14/2026
This work presents the design of a control logic for an electro-hydraulic brake-by-wire in series with an off-the-shelf ABS unit for motorsport applications. Validation is performed through hardware-in-the-loop testing with a complete hydraulic layout, including the brake-by-wire actuator, the ABS module, and brake calipers. State-of-the-art electro-hydraulic brake-by-wire systems are increasingly adopted in top-level motorsport and are now transitioning to high-performance road vehicles, in combination with ABS and ESC. However, due to motorsport regulations, racing brake-by-wire systems do not incorporate ABS functionality. To combine the performance of motorsport grade actuators with the ease of use required for non professional drivers, a series configuration between brake-by-wire and ABS represents a natural solution. This architecture is also relevant for future road vehicle applications, offering additional redundancy for autonomous driving-ready systems. A dedicated hardware-in
Milivinti, Massimiliano, Gimondi, Alex, Gobbi, Massimiliano, Cantoni, Carlo
Real-time Estimation of Brake Temperature using Physics-Informed Machine Learning Model2026-01-0810To be published on 09/14/2026
The current work presents a novel approach to estimate brake surface temperature in real time to aid in brake wear prognostics. Brake prognostics involve estimating the brake pad wear in real-time that helps in its predictive maintenance. Brakes are a safety critical system for vehicles, therefore, demands accurate and robust pad wear estimation, ensuring vehicle safety. However, it involves several challenges. The estimation of pad wear is fundamentally a two-stage process: the first stage involves the accurate prediction of brake pad surface temperature, while the second stage utilizes this thermal history to calculate cumulative material wear. A significant challenge in estimating brake pad wear without expensive sensor is that it is sensitive to the surface temperature prediction; any error in the thermal model propagates and compounds in the wear prediction stage. To identify surface temperature, traditional physical sensors are often cost-prohibitive or prone to failure in the
Gannavarapu, Shivadath, Pal, Anuj, Fan, Mengdi
A Study on TSC(Technical Safety Concept) design and verification in EMB(Brake By Wire) Systems2026-01-0801To be published on 09/14/2026
The Electro-Mechanical Brake (EMB) system, a dry-type Brake-by-Wire technology, eliminates hydraulic components by directly controlling friction braking through electrical actuators at each wheel. The architecture includes a Main Center Control Unit, a Backup Center Control Unit for redundancy, and four-Wheel Control Units, communicating via CAN FD. Compliance with ISO 26262 functional safety standards is critical due to the EMB system’s role in vehicle braking. As complexity increases, risks such as hardware failures and communication faults must be systematically addressed. This paper presents the design and verification of a Technical Safety Concept (TSC) for EMB systems in accordance with ISO 26262. Safety goals and Functional Safety Requirements derived from HARA analysis guide the System Architecture and TSC development. Key design principles include modularity, redundancy, fault detection, and fail-safe mechanisms. Verification is performed at both system and vehicle levels
KIM, Dokun
A Multi Body Dynamic Analysis of Click Noise Generated in Rear Brake Caliper2026-01-0815To be published on 09/14/2026
As customer awareness of brake-related NVH(Noise, Vibration and Harshness) continues to increase across the automotive industry, noise originating from braking systems is increasingly regarded as important indicator of vehicle quality. Among these issues, intermittent click noise from rear brake caliper is commonly noticed during low-speed driving and initial brake application and is frequently associated with customer dissatisfaction. In the automotive industry, this noise has primarily been addressed through empirical design modifications and component-level testing. However, due to its low reproducibility and impulsive response characteristics, making quantitative prediction and root-cause identification during the design phase difficult. While most previous brake NVH research has mainly focused on continuous vibration phenomena such as squeal and groan, fewer studies have examined single-event impact noise related to pad-to-carrier clearances, contact transitions, and frictional
Choi, Hyeontae, Kim, Sangbum, Park, Ilho, Kim, Taeuk, Kwon, Yongsik, Yang, Soonhong, Ma, Jaehyeon, Kim, Jinwook
A Virtual Methodology to Define Air Tightness Criterion for Brake Calipers Based on Experimental Data2026-01-0818To be published on 09/14/2026
Air tightness in brake calipers is a critical requirement for ensuring braking system reliability and safety. However, defining a clear and practical analytical criterion for air leakage prediction remains challenging due to the complex contact behavior at the seal–piston interface. This study presents a virtual methodology to define an air tightness criterion for brake calipers based on experimental evaluation and structural analysis. The seal squeeze ratio was selected as the primary design variable to evaluate its effect on sealing performance. Test samples with different seal squeeze ratios were manufactured, and air tightness was tested under controlled pneumatic pressure to determine when leakage occurred. In parallel, a finite element (FE) structural analysis was conducted to simulate the seal installation process and quantify the resultant contact pressure distribution between the seal and the piston surface. To support reliable structural analysis, preliminary experiments were
Cho, Inyong, Kim, Beomseok
Modeling Brake Torque Hysteresis for Chassis Controls Hardware In the Loop Simulation2026-01-0824To be published on 09/14/2026
It is hardly a new trend for on road, vehicle intensive tuning and testing of chassis control features such as Anti-Lock Brakes, Traction Control, and Electronic Stability Control to move away from vehicle testing and towards non-vehicle test platforms such as Hardware-In the Loop (HIL) simulations and even further into pure math-based simulations. However, a significant acceleration of these activities has been occurring recently in the automotive industry, reducing or eliminating calibration time on vehicles and amplifying the demand for highly representative, non-vehicle test platforms to calibrate and even to validate chassis controls features. In current state of the air HIL simulation, the input (brake pressure) to output (brake torque) of each wheel brake in a vehicle’s brake system is modeled relatively simplistically, including at most pressure and brake temperature sensitivities, usually in lookup table form. Each brake corner contains over 20 different friction interfaces
Antanaitis, David, Ridenour, Nick, Miller, Bryan, Karnjate, Timothy
The Biomechanics of Brake Pedal Feel2026-01-0796To be published on 09/14/2026
Brake pedal feel is arguably the most important driver-facing characteristic of a vehicle’s brake system, as it represents the main interaction between the brake system and the driver and is experienced by the driver in every trip taken. It has traditionally been characterized by three fundamental curves - deceleration versus force at the pedal pad, deceleration versus travel at the pedal pad, and travel at the pedal pad versus force (which is derivable from the other two curves). These characterizations, while useful, stop short of describing what the driver actually experiences - felt through the force in and contraction of his or her leg muscles. When brake pedal feel is traced away from the brake pedal pad and into the driver’s leg, a complex new system emerges, containing the brake system and the biomechanics of the driver. This expanded system is now subjected to - but can also help explain - influences such as seating position, foot position, brake pedal geometry, and the
Antanaitis, David, Antanaitis, Rebecca, Morris, Brock
Influence of Modified Fly Ash Content on the Properties of Resin-Based Friction Materials2026-99-1657To be published on 07/24/2026
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
Li, Xiaobiao, He, Kang, Zhao, Zhuanzhe, Wu, Bo, Sun, Fei
UAV Path Planning Method for Urban-Mountain Mixed Environments Based on Improved Divine Religions Algorithm2026-99-1840To be published on 07/17/2026
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
Fang, Lianyu, Yi, Wenjun
Analysis of Structural Stiffness Indicators of Manned Lunar Vehicles2026-99-1827To be published on 07/17/2026
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
Shen, Zhenghui, Wu, Yingjia, Yang, Jianfeng, Wang, Weijun, Zhang, Chongfeng, Han, Liangliang
Research on Quadrotor Trajectory Tracking Based on Model Predictive Control2026-99-1850To be published on 07/17/2026
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
Peng, Fei, Tao, Zhong, Gao, Qiang, Jia, Bobo
Modeling and Damping Optimization Design of Commercial Vehicle Cab Air Suspension System2026-99-1862To be published on 07/17/2026
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
Li, Saisai, Yang, Chang, Guo, Ruiling, Zhang, Zhongyuan, Liang, Dong, Wu, Shiyu
Research on Convergence Analysis of Multi Objective Optimization Algorithm for Lightweight Bus Chassis Architecture2026-99-1842To be published on 07/17/2026
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
Optimization Design of Automotive Handling Stability Based on ADAMS Insight2026-99-1801To be published on 07/17/2026
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
Li, Diannuo, Zhu, Jiale, Wang, Dongmei, Wei, Yi, Huang, Yuanyuan, Ban, Lu
Design and Analysis of Orthogonal Excitation Eddy Current Brake for High-Speed Trains2026-99-05137/10/2026
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
Huang, Liuwen, Zuo, Jianyong, Zhang, Yu
Design and Testing of a Quasi-Zero-Stiffness Vehicle-Mounted Isolation System with Additional Inerter2026-99-05207/10/2026
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
A Review of UAV Support Technologies for Low-Altitude Airspace Operation and Management2026-99-05977/10/2026
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
Gong, Lei, Ma, Zhenxiao, Luo, Qin
Research on the Influence of Suspension Characteristics on Ride Quality of Railway Wagon2026-99-05117/10/2026
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
Gao, Zhixiong, Ma, Kai, Xiao, Yanmei, Chen, Weidong, Wei, Xiao, Sha, Chengyu, Bian, Huihui
Enhancement of Tractive Trafficability for a Four-Track Unmanned Amphibious Tracked Vehicle2026-99-05787/10/2026
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
Chen, Yaoyao, Gao, Xue, Wang, Wenhao, Xu, Xiaojun
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