Browse Topic: Yaw

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Autonomous Racing Control Using Reinforcement Learning with Racing Line Guidance2026-01-0031To be published on 04/07/2026
In recent years, with the emergence of autonomous racing competitions such as Roborace, autonomous racing cars have become a prominent research focus and have undergone rapid development. This paper establishes a reinforcement learning-based decision-making and control framework for autonomous racing cars, achieving cooperative optimization between high-speed racing and safety control under extreme operating conditions. By integrating a Control Barrier Function constrained reward function for dynamic stability and a racing line-guided path optimization, the proposed framework achieves a synergistic balance between minimum lap time and operational safety. Dynamic stability domain constraints based on a two-degree-of-freedom single-mass rigid-body model and racing line optimization based on track geometric modeling are established. The phase plane stability boundary is constructed using the yaw rate method and double-line method, upon which Control Barrier Function constraints are
peng, tao, Zhang, Weiqi, Li, Zengwen, sudong, jiang
Aerodynamic Proximity Effects Between the DrivAer and AeroSUV Standard Models, Part 1 – Same-Lane Interactions2026-01-0605To be published on 04/07/2026
Road-vehicle platooning is traditionally defined as close-distance longitudinal following in laterally-aligned formation. In this paper, the effects of aerodynamic interactions on the drag of a two-vehicle system are examined by considering the influence of separation distance, cross winds, vehicle size and shape. Testing was undertaken at 30% scale in a large wind tunnel with road-representative freestream turbulence. Separation distances of 0.5, 1.0, and 2.0 vehicle lengths were examined over a range of yaw angles between ±15deg. A highlight of the current study is the characterization of platoon drag-reduction benefits for different sizes and shapes of the lead and follower models, by using a DrivAer model and an AeroSUV model, each with slant-back (Notchback or Fastback) and square-back (Estateback) variants, providing four distinct model pairings. Drag reduction for the lead model appears to be affected mainly by the size of the follower vehicle, while the follower model shows a
McAuliffe, Brian, Ghorbanishohrat, Faegheh
Research on Fault-Tolerant Control Strategy for Drive System Failure of Corner Module-by-Wire Chassis Vehicles2026-01-0620To be published on 04/07/2026
As an emerging research focus, corner module-by-wire chassis vehicles address the pain points of traditional chassis in flexibility, cost, and development efficiency, and have become one of the key infrastructures in the autonomous driving era. However, their large number of actuators significantly increases the risk of failures. This paper analyzes the characteristics of such vehicles and studies the fault-tolerant control for their drive system failures. Firstly, a full-vehicle dynamic model was established, with mathematical modeling conducted for the vehicle body, motor, tire, and corner module system models. Secondly, a hierarchical yaw stability control strategy was designed for the non-faulty actuator scenario: the decision-making and control layer adopted both Sliding Mode Control (SMC) and fuzzy PID control, selecting the method with better performance to output the additional yaw moment; the control allocation layer used a quadratic programming algorithm based on tire load
Zheng, Hongyu, Zhang, Tianhao, Zhang, Yuzhou
A Correction Method to Estimate Wake Effects for Aerodynamic Performance Metrics2026-01-0601To be published on 04/07/2026
Wake effects modify the aerodynamic performance of a road vehicle when driving in traffic. Analysis of wind-tunnel measurements conducted in flows with wake characteristics, using a traffic-wake-simulation system, suggests that conventional uniform-wind performance coefficients can be scaled, using wake-flow-field information, to predict the influence of wake effects. This paper presents a flow-field-averaging method that estimates a dynamic-pressure correction and yaw-angle correction for application to uniform-wind data, to account for changes in performance due to wake effects. This first-order method is shown to provide reasonably-good accuracy when reverse correcting the wind-tunnel wake-effects measurements. Drag-coefficient data for light-duty-vehicle models, which showed wake effects exceeding 20%, were corrected to within 5% of uniform-wind values, while data for heavy-duty-vehicle models, which showed wake effects exceeding 15%, were corrected to within 2% of uniform-wind
McAuliffe, Brian
Lateral stability and energy-saving integrated control of distributed drive vehicles with four wheel hub motors2026-01-0635To be published on 04/07/2026
Abstract: In order to improve the lateral stability and energy optimization of four-wheel hub motor distributed drive vehicles under complex road conditions, a layered control strategy for yaw stability is proposed. The upper controller is designed based on the sliding mode control principle to create a yaw moment controller, establishing both a two-degree-of-freedom model and a seven-degree-of-freedom model for the vehicle, tracking the desired yaw rate, desired center of mass side slip angle, actual yaw rate, and actual center of mass side slip angle to obtain the corresponding additional yaw moment. Moreover, the state of the vehicle is analyzed using the phase plane method of the center of mass side slip angle and yaw rate, and the total additional yaw moment for the vehicle is computed based on weighted calculations according to the state. Additionally, an unscented Kalman filter observer is established to enhance the tracking accuracy of the actual yaw rate and actual center of
shi, cheng'ao, liu, bingsen, Zou, Xiaojun, Wang, Tao, Zhang, Ming
A Cooperative AFS/DYC Control for FWDIEV Based on Dissipative Energy Method2026-01-0619To be published on 04/07/2026
To enhance the lateral stability of four-wheel-drive intelligent electric vehicles (FWDIEV) under extreme operating conditions, this paper proposes a cooperative control strategy integrating active front steering (AFS) and direct yaw moment control (DYC) based on dissipative energy method. A nonlinear three-degree-of-freedom vehicle model is established to analyze the evolution of the vehicle state phase trajectory. A quantitative lateral stability index is constructed using dissipative energy to accurately evaluate the vehicle's lateral dynamics. Utilizing dissipative energy and its gradient information, a time-varying stability boundary is defined under dynamic constraints, and adaptive weighting coordination between the AFS and DYC systems is designed to achieve coordinated control of front steering angle and additional yaw moment. A feedforward–model predictive control (FF-MPC) framework is developed, in which a feedforward module generates compensation based on driver intent to
Zhao, Kun, Zhao, Zhiguo, Wang, Yutao, Xia, Xue, Chen, Xi, Hu, Yingjia
Research on Vehicle Lateral Stability Under Flow Impact During Wading2026-01-0624To be published on 04/07/2026
The growing frequency of extreme rainfall events attributable to global climate change has heightened concerns regarding flood-related hazards to road traffic safety. Under wading conditions, vehicles become susceptible to lateral sliding, flotation, or rollover when exposed to lateral hydrodynamic impacts, jeopardizing both occupant safety and infrastructure integrity. Previous studies have primarily focused on longitudinal sliding instability—such as the critical flow velocity for vehicle motion initiation and buoyancy-related submersion depth—under forward or backward flow, employing theoretical analyses and flume experiments. However, research on the dynamic response of vehicles under lateral flow, the underlying mechanisms of lateral skidding, and multi-degree-of-freedom instability modes remains relatively limited. To address this gap, this study establishes a multi-body vehicle dynamics model for lateral flow conditions, incorporating lateral hydraulic forces and tire-road
Wei, Haoting, Tan, Gangfeng, Lang, Tao, Liu, chongjian, Tang, Jingning
Oscillatory Behavior of Understeering Vehicles2026-01-0623To be published on 04/07/2026
Oscillations in understeering vehicles are occasionally described in the literature, primarily in terms of the poles of the yaw rate response, but perhaps not completely appreciated in their complexity. This work shows that as speeds of the understeering vehicle increase, the increasingly underdamped poles of the yaw rate transfer function combine with the effects of a low frequency zero and a reduced steady-state response to result in oscillations greater than would be expected from eigenvalues alone. A speed range for acceptable yaw rate response is suggested, and it is shown that a typical understeering passenger car operates within this range. As the understeering vehicle’s speed increases beyond this range, the high speed limit of the oscillation frequency is found.
Williams, Daniel
Path Following Strategy for Multi-Axle Vehicles via Nash Game-Based Coordinated Control of AFS and DYC2026-01-0629To be published on 04/07/2026
Due to their complex structure and large inertia, multi-axle hub electric drive vehicles often suffer from response delays and insufficient control sensitivity. To improve path tracking accuracy and handling stability under high-speed and low-adhesion conditions, this paper proposes a coordinated control strategy that integrates a three-dimensional stability assessment with a Nash game-based approach for active front steering (AFS) and direct yaw moment control (DYC) systems. A path tracking control model tailored for multi-axle vehicles is developed, and a robust Tubular Model Predictive Control (Tube-MPC) method is employed to enhance trajectory tracking performance under model uncertainties and external disturbances. Within the prediction horizon of Tube-MPC, the system continuously evaluates whether the vehicle state remains within the stable region. If the state exceeds this region, a Nash game-based coordination mechanism is activated to formulate a multi-objective control game
Lv, Xin, Liu, Zuyang, Shen, Yanhua, Wang, Kaidi
Evaluating the Impact of Drag Coefficient Changes on Driving Energy Using a Probability Distribution Model of Yaw Angle Based on Empirical Data from North American Highways2026-01-0615To be published on 04/07/2026
This study estimates the impact on driving energy of differences in aerodynamic characteristics for yaw angle from natural wind during North American Highway mode driving. A previous study[1] clarified the potential to estimate the fuel consumption impact of natural wind by integrating the CD yaw characteristics and yaw angle occurrence frequency. The natural wind was measured on a vehicle while driving a representative North American Highway test course[2]. The driving energy is predicted from the obtained yaw frequency and CD yaw sweep data in a wind tunnel. Measurements were conducted every weekday for 8 hours in 2023, covering 70% of the traffic volume. The validity of the measurement period was evaluated by the deviation from the annual average of wind direction and speed. Since yaw frequency varies depending on the road environment, it is necessary to weight the road environment type frequency when calculating the driving energy. The frequency was calculated using machine
Onishi, Yasuyuki, Nucera, Fortunato, Nichols, Larry, Metka, Matt
Pre-Crash Scenario Analysis and Generation for Integrated Safety System Virtual Testing with Real Accident Data2026-01-0062To be published on 04/07/2026
Integrated active and passive safety protection systems have made substantial contributions to reducing traffic accidents and mitigating human injuries. However, assessing such systems through vehicle collision tests is limited, as this approach can not cover the wide range of accident scenarios. To address this gap, identifying and generating representative pre-crash scenarios from real-world accidents provides key boundary conditions for the set up of virtual test scenarios. In this study, we used the Future Mobile Traffic Accident Scenario Study (FASS) dataset to reconstruct 112 two-wheeler accidents. For each case, we extracted pre-crash dynamic information, static attributes, and environmental context. An auto-encoder was employed to encode high-dimensional features of scenarios, and K-means clustering was applied to categorize the accidents into eight representative pre-crash scenarios. For each scenario, we examined the motion states of participants and further compared the
Wang, Guojie, Gao, Xin, Liu, Siyuan, Liu, Jiaxin, Li, Quan, shi, liangliang, Nie, Bingbing
Four-Wheel Independent Steering Vehicle Control under Wheel-Corner Brake Faults10-10-04-00282/18/2026
Wheel-corner brake failures can significantly deteriorate vehicle stability and safety, since unbalanced braking forces may introduce an undesired yaw moment. This work investigates a fault-tolerant control strategy for Active Wheel-Corner Systems, exploiting Four-Wheel Independent Steering (4WIS) to mitigate such effects and preserve vehicle stability when brake actuator malfunctions occur. Unlike many existing approaches, the proposed framework does not require explicit fault detection or quantification as a prerequisite for corrective action, eliminating potential delays and uncertainties associated with fault-diagnosis schemes. A reference model for yaw rate and sideslip angle, incorporating combined longitudinal and lateral dynamics, is proposed, and a Weighted Pseudo-Inverse Control Allocation (WPCA) scheme is employed to distribute corrective actions among the four steering angles according to each tire’s capability, compensating for yaw moment imbalances caused by degraded
Sonnino, Samuel, Melzi, Stefano, Caresia, Pietro, Manzoni, Alessandro, Vaini, Gianluca
Modelling and Simulation of Key Vehicle Dynamics Parameters for a Conceptual Race Car2026-26-00851/16/2026
Vehicle dynamics is a vital area of automotive engineering that focuses on analyzing how a vehicle responds to driver inputs and external factors like road conditions and environmental influences. Achieving optimal performance, safety, and ride comfort requires a detailed understanding of longitudinal, lateral, and vertical dynamic behavior. The objective of this paper is to develop and validate the model of a concept Race car and evaluate its vehicle dynamics behavior using IPG CarMaker, a high-fidelity virtual testing environment widely used in industry. The model incorporates a range of vehicle parameters, including suspension parameters like spring and damper characteristics, mass distribution, tire properties and powertrain parameters. The performance evaluation is done as per standard guidelines, including Constant Radius turn test, Sine Steer test and other standard tests like Acceleration, Braking along with Ride and Comfort classification. The key parameters that are
Agrewale, Mohammad Rafiq B., Vaish, Ujjwal
High-Fidelity Modeling of Vehicle Dynamics for Control-Oriented Stability Enhancement2026-26-00931/16/2026
This study presents an integrated vehicle dynamics framework combining a 12-degree-of-freedom full vehicle model with advanced control strategies to enhance both ride comfort and handling stability. Unlike simplified models, it incorporates linear and nonlinear tire characteristics to simulate real-world dynamic behavior with higher accuracy. An active roll control system using rear suspension actuators is developed to mitigate excessive body roll and yaw instability during cornering and maneuvers. A co-simulation environment is established by coupling MATLAB/Simulink-based control algorithms with high-fidelity multibody dynamics modeled in ADAMS Car, enabling precise, real-time interaction between control logic and vehicle response. The model is calibrated and validated against data from an instrumented test vehicle, ensuring practical relevance. Simulation results show significant reductions in roll angle, yaw rate deviation, and lateral acceleration, highlighting the effectiveness
Duraikannu, Dinesh, Dumpala, Gangi Reddi
Kinematics-Based Differential In-Situ Steering Control for Distributed-Drive Electric Vehicles2025-01-733312/31/2025
In-situ steering can significantly improve the vehicle's maneuverability in narrow spaces, especially suitable for extreme scenarios such as off-road driving and professional operations. For distributed drive electric vehicles, kinematics-based left and right wheel differential control and dynamics-based vehicle yaw control can achieve in-situ steering, however, the two methods have different effects on in-situ steering performance. This paper proposes a kinematics-based distributed drive electric vehicle differential in-situ steering control method, which first establishes the functional relationship between the drive pedal and the expected yaw rate, so that the driver can adjust the steering speed. The initial reference wheel speed is calculated from the expected yaw rate, and the reference wheel speed is adjusted by feedback from the actual and expected yaw rate errors to improve the tracking accuracy. On this basis, the sliding mode control algorithm is used to calculate the
Chen, Jingxu, Li, Yang, Zhang, Yi, Zhao, Hongwang, Qiao, Miaomiao, Wang, Beibei, Wu, Dongmei
Coordinated Control of DYC/ABS for Cornering Braking Based on Driver Intention2025-01-734012/31/2025
This paper proposes a DYC/ABS coordinated control strategy for cornering and braking based on driver intention. A hierarchical control structure is established, where the upper-level controller uses a vehicle dynamics model to calculate the additional yaw moment required by the DYC controller to track the desired yaw rate and sideslip angle, as well as the driver’s intended braking intensity. Taking multiple constraints into account, a quadratic programming algorithm is employed to optimize the distribution of braking forces among the four wheels. The lower-level ABS controller is designed with multiple thresholds and corresponding control phases to precisely regulate the hydraulic pressure of individual wheel cylinders. In emergency braking scenarios where ABS intervention may conflict with the upper-layer braking force allocation, a rule-based, stepwise diagonal pressure reduction compensation strategy is proposed. This strategy fully considers the influence of longitudinal and
Zou, Yan, Ma, Yao, Kong, Yan, Pei, Xiaofei
Centralized Control of Distributed Drive Steer-by-Wire Chassis Considering Tire Force Zoning Constraints2025-01-732912/31/2025
Distributed drive steer-by-wire chassis has significant potential for enhancing vehicle dynamics performance, while also presenting great challenges to vehicle dynamics control. To address the coordination among multiple chassis subsystems and the coupled control allocation of longitudinal and lateral tire forces, this paper proposes a centralized control framework based on optimal yaw moment control. By analyzing the impact of longitudinal and lateral tire forces on vehicle yaw moments, a method for allocating longitudinal and lateral forces with maximum yaw moment as the objective is proposed. On this basis, a hierarchical control architecture is designed, including the driver control layer, motion control layer, tire force allocation layer, and actuator execution layer, to achieve centralized domain control of longitudinal and lateral dynamics in distributed drive steer-by-wire chassis. Finally, the proposed centralized controller is validated using offline simulation and real-time
Wu, Dongmei, Guo, Chunzhi, Liu, Changsheng, Xia, Xin, Li, Miao, Liu, Wei
Research and HIL Test of Rear Wheel Steering Control Strategy Based on Zero Sideslip Angle2025-01-732312/31/2025
This paper briefly introduces the vehicle characteristics of four-wheel steering. Based on the parameters of an electric SUV, a linear two-degree-of-freedom vehicle dynamics model is established, and the transfer function of the rear wheel steering angle is derived to keep the sideslip angle at the center of gravity(CoG) constant at zero and proportional to the front wheel steering angle under steady state. The active rear wheel steering control strategy based on zero sideslip angle is established by MATLAB/Simulink, and a co-simulation model is built with CarSim and the HIL test bench to simulate and analyze the proposed control strategy. Subsequently, through classic handling stability test conditions such as the snake test, steering angle step test, and double lane change test, the influence of active rear wheel steering on vehicle dynamic response indicators such as sideslip angle, lateral acceleration, and yaw rate is studied, and the control effect is compared with that of the
Xu, Xiangfei, Qu, Yuan, Liu, Jiabao
Full-State Decoupling Motion Control Strategy for Distributed Vehicle via Bayesian Parameter Optimization10-10-01-000711/26/2025
With the rapid development of autonomous driving technology, unmanned ground vehicles (UGVs) are gradually replacing humans to perform tasks such as reconnaissance, target tracking, and search in special scenarios. Omnidirectional mobility based on rapid adjustment of vehicle heading posture enhances the applicability of UGVs in specialized scenarios. Omnidirectional mobility signifies the capability for rapid adjustments to the vehicle’s heading angle, longitudinal velocity, and lateral velocity. Traditional vehicles are constrained by the limitations of under-actuation, which prevents active regulation of lateral movement. Instead, they rely on the coordinated regulation of longitudinal and yaw movements, failing to meet the requirements for omnidirectional mobility. Distributed vehicles featuring steering distributed between the front/rear axles and four-wheel independent drive leverage the over-actuation advantages provided by multi-actuator coordinated control, making them
Chen, Guoying, Dong, Jiahao, Wang, Xinyu, Zhao, Xuanming, Bi, Chenxiao, Gao, Zhenhai, Zhang, Yanping, He, Rong
Numerical Study to Predict the Impact of Geometric Modification on Aero-Acoustic Behaviour of a Commercial Vehicle2025-28-042610/30/2025
To address the growing concern of increasing noise levels in urban areas, modern automotive vehicles need improved engineering solutions. The need for automotive vehicles to have a low acoustic signature is further emphasized by local regulatory requirements, such as the EU's regulation 540/2014, which sets sound level limits for commercial vehicles at 82 dB(A). Moreover, external noise can propagate inside the cabin, reducing the overall comfort of the driver, which can have adverse impact on the driving behavior, making it imperative to mitigate the high noise levels. This study explores the phenomenon of change in acoustic behavior of external tonal noise with minor geometrical changes to the A-pillar turning vane (APTV), identified as the source for the tonal noise generation. An incompressible transient approach with one way coupled Acoustics Wave solver was evaluated, for both the baseline and variant geometries. Comparison of CFD results between baseline and variant showed
Pawar, Sourabh, Sharma, Shantanu, Singh, Ramanand
Exploring the Correlation between Physiological States and Driving Behavior on Highways with Integrated ECG Measurements2025-01-02927/2/2025
Human driver errors, such as distracted driving, inattention, and aggressive driving, are the leading causes of road accidents. Understanding the underlying factors that contribute to these behaviors is critical for improving road safety. Previous studies have shown that physiological states, like raised heart rates due to stress and anxiety, can influence driving behavior, leading to erratic driving and an increased risk of accidents. In this study, we conducted on-road tests using a measurement system based on the Driver-Driven vehicle-Driving environment (3D) method. We collected physiological signals, specially electrocardiography (ECG) data, from human drivers to examine the relationship between physiological states and driving behaviors. The aim was to determine whether ECG can serve as an indicator of potential risky driving behaviors, such as sudden acceleration and frequent steering adjustments. This information enables automated driving (AD) systems to intervene in dangerous
Ji, Dejie, Flormann, Maximilian, Bollmann, Julian, Henze, Roman, Deserno, Thomas M.
Yaw Motion of Motor Vehicles2025-01-50436/20/2025
Vehicular accident reconstruction is intended to explain the stages of a collision. This also includes the description of the driving trajectories of vehicles. Stored driving data is now often available for accident reconstruction, increasingly including gyroscopic sensor readings. Driving dynamics parameters such as lateral acceleration in various driving situations are already well studied, but angular rates such as those around the yaw axis are little described in the literature. This study attempts to reduce this gap somewhat by evaluating high-frequency measurement data from real, daily driving operations in the field. 813 driving maneuvers, captured by accident data recorders, were analyzed in detail and statistically evaluated. These devices also make it possible to record events without an accident. The key findings show the average yaw rates as a function of driving speed as well as the ratio between mean and associated peak yaw rate. Beyond that, considerably lower yaw rates
Fuerbeth, Uwe
Analysis and Evaluation of Roll Safety Thresholds of Tractor Semi-Trailer Vehicles during Turning Maneuvers Based on the Yaw Rate of Vehicle Bodies and Roll Safety Factor02-18-04-00246/5/2025
Hung, Ta Tuan
Experimental Investigation into Modulated Aeroacoustic Cabin Noise Arising from Unsteady Flow Conditions2025-01-00295/5/2025
The unsteady wind conditions experienced by a vehicle whilst driving on the road are different to those typically experienced in the steady-flow wind tunnel development environment, due to turbulence in the natural wind, moving through the unsteady wakes of other road vehicles and travelling through the stationary wakes generated by roadside obstacles. This paper presents an experimental approach using a large SUV-shaped vehicle to assess the effect of unsteady wind on the modulated noise performance, commonly used to evaluate unsteady wind noise characteristics. The contribution from different geometric modifications were also assessed. The approach is extended to assess the pressure distribution on the front side glass of the vehicle, caused by the aerodynamic interactions of the turbulent inflow in straight and yawed positions, to provide insight into the noise generation mechanisms and differences in behaviour between the two environments. The vehicle response to unsteady wind
Jamaluddin, Nur Syafiqah, Oettle, Nicholas, Staron, Domenic
Simulation and Experimental: Enhanced Stability Control of Electric Vehicle Based on Phase Plane Boundary Analysis10-09-02-00175/5/2025
To optimize vehicle chassis handling stability and ride safety, a layered joint control algorithm based on phase plane stability domain is proposed to promote chassis performance under complicated driving conditions. First, combining two degrees-of-freedom vehicle dynamics model considering tire nonlinearity with phase plane theory, a yaw rate and side slip angle phase plane stability domain boundary is drew in real time. Then based on the real-time stability domain and hierarchical control theory, an integrated control system with active front steering (AFS) and direct yaw moment control (DYC) is designed, and the stability of the controller is validated by Lyapunov theory. Finally, the lateral stability of the vehicle is validated by Simulink and CarSim simulations, real car data, and driving simulators under moose test and pylon course slalom test. The experimental results confirm that the algorithm can enhance the maneuverability and ride safety for intelligent vehicles.
Liao, Yinsheng, Zhang, Zhijie, Su, Ailin, Zhao, Binggen, Wang, Zhenfeng
Road Surface Adaptive Stationary Steering Coordinated Control of Four-Wheel Hub Motor Vehicles2025-01-50314/29/2025
The wheel hub motor–driven electric vehicle, characterized by its independently controllable wheels, exhibits high torque output at low speeds and superior dynamic response performance, enabling in-place steering capabilities. This study focuses on the control mechanism and dynamic model of the wheel hub motor vehicle’s in-place steering. By employing differential torque control, it generates the yaw moment needed to overcome steering resistance and produce yaw motion around the steering center. First, the dynamic model for in-place steering is established, exploring the various stages of tire motion and the steering process, including the start-up, elastic deformation, lateral slip, and steady-state yaw. In terms of control strategy, an adaptive in-place steering control method is designed, utilizing a BP neural network combined with a PID control algorithm to track the desired yaw rate. Additionally, a control strategy based on tire/road adhesion ellipse theory is developed to
Huang, Bin, Cui, Kangyu, Zhang, Zeyang, Ma, Minrui
On the Critical Importance of Physical Modelling for the Analysis of Coast-Down Data2025-01-87744/1/2025
Novel experimental and analytical methods were developed with the objective of improving the reliability and repeatability of coast-down test results. The methods were applied to coast-down tests of a SUV and a tractor-trailer combination, for which aerodynamic wind-tunnel data were available for comparison. The rationale was to minimize the number of unknowns in the equation of motion by measuring rolling and mechanical resistances and wheel-axle moments of inertia, which was achieved using novel experimental techniques and conventional rotating-drum tests. This led to new modelling functions for the rolling and mechanical resistances in the equation of motion, which was solved by regression analysis. The resulting aerodynamic drag coefficient was closer to its wind-tunnel counterpart, and the predicted low-speed road load was closer to direct measurements, than the results obtained using conventional methods. It is anticipated that applying the novel techniques to characterize the
Tanguay, Bernard, de Souza, Fenella
Verification of the Impact of Coefficient of Drag Variation Due to Natural Wind on Fuel Consumption Based on Actual Driving Data2025-01-87784/1/2025
The natural wind experienced on public roads can increase the yaw angle and therefore drag coefficient (CD), which may contribute to the discrepancy between catalog fuel economy and actual fuel economy. The impact of yaw characteristics alone on fuel economy during actual driving has not been verified or proven as it is difficult to obtain actual driving data under uniform conditions. For this reason, shape optimization is normally performed at zero-yaw through the aerodynamic development phases. In this paper, two vehicles with different yaw sensitivity characteristics are driven simultaneously, and fuel economy measurements are performed simultaneously with ambient airflow, environment, and vehicle conditions. The results where the conditions of the two vehicles match are extracted to clarify the impact of the differences of yaw characteristics on fuel economy. The obtained results matched the values predicted by theoretical calculations for the impact of yaw angle on fuel economy
Onishi, Yasuyuki, Nichols, Larry, Metka, Matt, masumitsu, Yasutaka, Inoue, Taisuke
Investigation of Flow Structures in Different Body Types Contributing to Drag Change Due to Crosswind2025-01-87674/1/2025
To reduce aerodynamic drag during real-world driving, it is essential to consider the effects of crosswinds. The yaw angle dependence of aerodynamic drag is known to vary based on the vehicle body type; however, there are limited studies on the physical mechanisms underlying this difference, particularly through detailed visualizations of the flow structure and its response to yaw angles. This study investigates the differences in flow structures between an SUV and a notchback to understand the mechanism responsible for the variation in yaw angle dependence of CD under quasi-steady yaw angle conditions. Numerical simulations and wind tunnel tests were conducted for both the SUV and the notchback at yaw angles of 0°, 2°, and 5°. Crossflow and total pressure were employed as indicators for visualizing the flow structure, with a focus on the wake behind the vehicle in the visualizations of the wind tunnel tests and simulations. Additionally, isosurfaces of the crossflow velocity magnitude
Nakata, Akihiro, Okamoto, Satoshi, Nishida, Shuhei, Morikawa, Yosuke, Nakashima, Takuji
Optimal Torque Vectoring Control for Autonomous Electric Vehicles Considering Ride Comfort2025-01-83104/1/2025
This study introduces an innovative torque vectoring control strategy designed to enhance ride comfort in autonomous electric vehicles. The approach seamlessly integrates steering and rear axle force control within a model predictive control (MPC) framework, enabling real-time optimization of comfort and handling performance. The proposed control method is applied to a two-rear-motor vehicle model, where the MPC algorithm adjusts steering angles and tire forces to minimize discomfort caused by yaw rate and lateral acceleration. Simulation results from a lane-change scenario demonstrate significant improvements in comfort metrics compared to conventional torque vectoring control strategies. The findings highlight the ability of the proposed method to significantly enhance ride comfort without compromising vehicle dynamics. This integrated and adaptive control strategy offers a promising solution for improving passenger satisfaction in autonomous electric vehicles, with potential
Zhao, Bolin, Lou, Baichuan, He, Xianqi, Xue, Wanying, Lv, Chen
Aerodynamic Effect on Vehicle Handling2025-01-87544/1/2025
Vehicle handling is significantly influenced by aerodynamic forces, which alter the normal load distribution across all four wheels, affecting vehicle stability. These forces, including lift, drag, and side forces, cause complex weight transfers and vary non-linearly with vehicle apparent velocity and orientation relative to wind direction. In this study, we simulate the vehicle traveling on a circular path with constant steering input, calculate the normal load on each tire using a weight transfer formula, calculate the effect of lift force on the vehicle on the front and rear, and calculate the vehicle dynamic relation at steady state because the frequency of change due to aerodynamic load is significantly less than that of the yaw rate response. The wind velocity vector is constant while the vehicle drives in a circle, so the apparent wind velocity relative to the car is cyclical. Our approach focuses on the interaction between two fundamental non-linearity’s: the nonlinear
Patil, Harshvardhan, Williams, Daniel
Design Parameter Impact of Wind-Averaged Drag Optimization2025-01-87724/1/2025
With the increasing prevalence of electric vehicles (EVs), decreasing vehicle drag is of upmost importance, as range is a primary consideration for customers and has a direct bearing on the cost of the vehicle. While the relationship between drag and range is well understood, there exists a discrepancy between the label range and the real-world range experienced by customers. One of the factors influencing the difference is the ambient wind condition that modifies the resultant air speed and yaw angle, which is typically minimized during SAE coast-down testing. The following study implements a singular wind-averaged drag (WAD) coefficient which is derived from a 3-point yaw curve to show the impact of yaw as compared to the zero-yaw condition. This leads to an interesting dilemma for the vehicle aerodynamicist: whether to optimize the vehicle's exterior shape for low wind (zero yaw) conditions or for real-world conditions where the ambient wind generally produces a few degrees of yaw
Kaminski, Meghan, D'Hooge, Andrew, Borton, Zackery
YRSRA: Yaw and Roll Stable Region Analytics for Ground Vehicle System with 5G-V2X2025-01-87994/1/2025
Since most of the existing studies focus on the identification of the yaw stable region, but ignore the identification of the roll stable region, this article presents a software tool YRSRA for calculating both the yaw and roll stable region for ground vehicle system with 5G-V2X. And the frequency of rollover instability of commercial vehicles such as trucks and buses is not low, and the cost of rollover accidents is often greater than the cost of yaw instability accidents. Therefore, it is necessary to identify the stability region of yaw and roll at the same time. Firstly, the iterative model of yaw rate and slip angle is constructed through deducing the two-degree-of-freedom vehicle dynamics. Secondly, the load transfer ratio (LTR) is coded with given yaw rate and slip angle. Thirdly, several Illustrative examples are depicted, such as variation of steer angle, road adhesion coefficient and vehicle speed. The software features an easy to generate yaw and roll stability region by on
Tu, Lihong, Zeng, Dequan, Zhang, Zhouping, He, Qixiao, Zhao, Shuqi, Sun, Jing, Wang, Aichun, Yu, Qin, Ming, Jinghong, Wang, Xiaoliang, Hu, Yiming
Stability Control for Distributed Drive Electric Vehicles Using Particle Filter and Fuzzy Integral Sliding Mode Control2025-01-88114/1/2025
The Distributed Drive Electric Vehicles (DDEVs) offer advantages such as independently controllable driving and braking forces at each wheel, rapid response, and precise control. These features enable effective electronic stability control (ESC) by appropriately distributing torque across each wheel. However, traditional ESC systems typically employ single-wheel hydraulic differential braking, failing to fully utilize the independent torque control capabilities of DDEVs. This study proposes a hierarchical control strategy for distributed driving and braking ESC based on particle filter (PF) and fuzzy integral sliding mode control (FISMC). First, the vehicle state estimation layer uses a three-degree-of-freedom vehicle model and the PF to estimate sideslip angle and vehicle speed. Next, the target torque decision layer includes a target speed tracking controller and a yaw moment decision controller. The yaw moment decision controller uses the FISMC to determine additional yaw moment by
Li, Xiaolong, Zheng, Hongyu, Kaku, Chuyo
Investigation of Skin Friction Topology on the AeroSUV Using GLOF Meter2025-01-87824/1/2025
In this study, the aerodynamics and surface flow field of a 1/5 scale SUV vehicle model called “AeroSUV” were experimentally investigated. The aerodynamics and surface flow field investigations were carried out in the wind tunnel at Hiroshima University with a Reynolds number ReL = 1.2×106, baseline yaw angle β = 0° and crosswind conditions β = 5°, 10° and 15° for two rear ends, Estateback and Fastback. The results provide aerodynamic information and detailed surface flow field information for a standard middle-class SUV vehicle with different rear ends, which is important for automotive design. By applying GLOF measurements to automotive aerodynamics, the skin friction topology was revealed in detail as surface flow field information that is useful for understanding the physics of the flow. The skin friction topology clearly shows the separation lines, reattachment lines, and focus points associated with the separation flow, longitudinal vortices and recirculation vortices of this
Hijikuro, Masato, Shimizu, Keigo, Nakashima, Takuji, Hiraoka, Takenori
A Sled Test Methodology for 25% Offset Crash Tests2025-01-87374/1/2025
Sled crash tests are an important tool to develop automotive restraint systems. Compared with full-scale crash tests, the sled test has a shorter development cycle of the restraint system and lower cost. The objective of the present study is to create a cost-effective sled test methodology, calculate the optimal static yaw angle and loading curves, and analyze the motion response and injuries of the dummy in the small overlap crash test. The effectiveness of the proposed methodology was verified under two typical small overlap frontal crash modes: “energy-absorption” and “sideswipe”. The results show that with the calculated yaw angle α, the HIC was different from the small overlap crash model, but all remaining indices were within 5% of the injury criteria. All International Organization for Standardization (ISO) values between the combined accelerations of all parts of the dummy and those of the basic model exceeded 0.75, and some values were above 0.8. Therefore, the proposed sled
Yu, Liu, Chen, Jianzhuo, Wan, Ming Xin, Fan, Tiqiang, Yang, Peilong, Nie, Zhenlong, Ren, Lihai, Cheng, James Chih
Study on Emergency Obstacle Avoidance Lateral Stability Control of Tractor Semitrailer Vehicles2025-01-82964/1/2025
As a crucial component of highway freight systems, tractor semitrailer vehicles play a key role in the transportation industry. However, their complex vehicle structure can lead to significant lateral instability during emergency obstacle avoidance, posing challenges to the vehicle's dynamic stability and safety. To enhance the emergency obstacle avoidance lateral stability of tractor semitrailer vehicles, a direct yaw moment lateral stability control strategy based on differential driving/braking is proposed. First, a 3-degree-of-freedom ideal linear dynamic model of the tractor-semitrailer is established, and its accuracy is validated. Then, a lateral stability control strategy for emergency obstacle avoidance is proposed. The upper-layer controller employs an improved feedforward differential model-free adaptive control (IMFAC) method to track the target yaw rate and vehicle sideslip angle, while the lower-layer controller focuses on optimizing tire load rate. Additionally, a drive
Guo, Shaozhong, Dou, Jingyang
Coordinated Control Strategy for Longitudinal, Lateral, and Vertical Motions of Distributed Electric Vehicles Based on Model Predictive Control2025-01-83004/1/2025
Distributed electric vehicles, equipped with independent motors at each wheel, offer significant advantages in flexibility, torque distribution, and precise dynamic control. These features contribute to notable improvements in vehicle maneuverability and stability. To further elevate the overall performance of vehicles, particularly in terms of handling, stability, and comfort, this paper introduces an coordinated control strategies for longitudinal, lateral, and vertical motion of distributed electric vehicles. Firstly, a full-vehicle dynamics model is developed, encompassing interactions between longitudinal, lateral, and vertical forces, providing a robust framework for analyzing and understanding the intricate dynamic behaviors of the vehicle under various operating conditions. Secondly, a vehicle motion controller based on Model Predictive Control is designed. This controller employs a sophisticated multi-objective optimization algorithm to manage and coordinate several critical
Jia, Jinchao, Yue, Yang, Sun, Aobo, Liu, Xiao-ang
A Torque Distribution Strategy for the Six-Wheeled Lunar Rover2025-01-83084/1/2025
As a crucial tool for lunar exploration, lunar rovers are highly susceptible to instability due to the rugged lunar terrain, making control of driving stability essential during operation. This study focuses on a six-wheel lunar rover and develops a torque distribution strategy to improve the handling stability of the lunar rover. Based on a layered control structure, firstly, the approach establishes a two-degree-of-freedom single-track model with front and rear axle steering at the state reference layer to compute the desired yaw rate and mass center sideslip angle. Secondly, in the desired torque decision layer, a sliding mode control-based strategy is used to calculate the desired total driving torque. Thirdly, in the torque distribution layer, the optimal control distribution is adopted to carry out two initial distributions and redistribution of the drive torque planned by the upper layer, to improve the yaw stability of the six-wheeled lunar rover. Finally, a multi-body dynamics
Liu, Pengcheng, Zhang, Kaidi, Shi, Junwei, Yang, Wenmiao, Zhang, Yunqing, Wu, Jinglai
Sensitivity Analysis of Virtual Crash Simulation Software Using Design of Experiments (DOE)2025-01-86934/1/2025
This paper is a continuation of a previous effort to evaluate the post-impact motion of vehicles with high rotational velocity within various vehicle dynamic simulation softwares. To complete this goal, this paper utilizes a design of experiments (DOE) method. The previous papers analyzed four vehicle dynamic simulation software programs; HVE (SIMON and EDSMAC4), PC-Crash and VCRware, and applied the DOE to determine the most sensitive factors present in each simulation software. This paper will include Virtual Crash into this methodology to better understand the significant variables present within this simulation model. This paper will follow a similar DOE to that which was conducted in the previous paper. A total of 32 trials were conducted which analyzed ten factors. Aerodynamics, a factor included in the previous DOE, was not included within this DOE because it does not exist within Virtual Crash. The same three response variables from the previous DOE were measured to determine
Roberts, Julius, Civitanova, Nicholas, Stegemann, Jacob, Buzdygon, David, Thobe, Keith
Stability-Based Coordinated Control for Distributed Drive Electric Vehicle Trajectory Tracking and Handling Stability2025-01-83074/1/2025
To address the issue of poor yaw stability in distributed drive electric vehicles under extreme trajectory tracking conditions, this paper proposes a novel control approach that coordinates upper-layer trajectory tracking and stability control with lower-layer active front steering (AFS) and direct yaw moment control (DYC). Firstly, a stability domain boundary is defined in the β−β̇phase plane, and the instability factor is derived based on boundary line characteristics. This factor is used as a weight in the objective function to establish a model predictive control (MPC) for trajectory tracking and handling stability, thereby adjusting the control target weights for both objectives. Secondly, fuzzy logic is used to change the boundary of the phase plane transition field according to the vehicle state to dynamically adjust the intervention timing of the stability control, while AFS and DYC control are used to modify the front wheel steering angle and yaw moment control in the MPC
Dou, Jingyang, Wu, Jinglai, Zhang, Yunqing
Direct Yaw Moment Control for Distributed Drive Electric Vehicles Based on Full-Order Terminal Sliding Mode2025-01-70241/31/2025
Distributed Drive Electric Vehicles (DDEVs), as a significant development form of electric vehicles, have garnered considerable focus owing to their excellent energy utilization efficiency and the capability for flexible torque distribution. However, DDEVs still face numerous challenges in practical applications, particularly in the coordinated control of hub motors and system stability. This paper focuses on the whole-vehicle control technology and distributed control theory of DDEVs and researches the active safety function of Direct Yaw-moment Control (DYC): acceleration and turning. A full-order terminal sliding mode controller is utilized to suppress the chattering of sliding mode control and to reduce torque fluctuations in the output. Results show that the proposed method can enhance the vehicle’s yaw stability and driving safety with the linear sliding mode.
Zhou, Minghao, Wu, Weiwei, Fei, Xueran, Chen, Zhenqiang, Jiang, Longbin, Cai, William
Design of Electric Power Steering Control for Compensating the Torque Steer Effect due to Torque Vectoring Control10-09-02-00101/24/2025
The increased popularity of electric vehicles featuring distributed powertrains is enabling an easy and cost-effective implementation of torque vectoring. This is a renowned technique for controlling vehicle lateral dynamics having the objective of improving both vehicle handling and stability. Nevertheless, the application of torque vectoring at the front axle can increase the difficulty of usual driving tasks. This is because differential longitudinal forces at front tires generate a steering wheel torque, which can be badly perceived by the driver, up to the point of jeopardizing the benefits of having a torque vectoring control. The aim of this article is thus to study in detail the steering torque corruption caused by front axle torque vectoring for proposing some electric power steering control strategies compensating for this effect. Indeed, the electric power steering controllers developed in this study are designed based on the analytical derivation of the torque steer theory
Asperti, Michele, Vignati, Michele, Sabbioni, Edoardo
Path Tracking and Direct Yaw Moment Integrated Control for Autonomous Vehicles with Steer-by-Wire Based on LMI and Terminal Sliding Mode2024-01-704812/13/2024
This paper proposes a path-tracking and direct yaw moment integrated control strategy based on linear matrix inequality (LMI) and terminal sliding mode for autonomous distributed drive electric vehicles (A-DDEVs) equipped with a steer-by-wire (SBW) system. This strategy effectively attenuates the effects of external disturbances and parameter uncertainties on path tracking, thereby enhancing vehicle safety. The control-oriented vehicle model accounts for roll effects, with the system state matrix incorporating mismatched norm bounded uncertainties. Firstly, for overall vehicle motion control, an LMI-based integral sliding mode controller (ISMC) is designed to generate desired front wheel steering angle and additional yaw moment. This aims to converge path-tracking errors and ensure vehicle stability. A sufficient condition for the existence of a sliding surface ensuring asymptotic stability of the sliding mode dynamics is provided, along with a demonstration of the attainability of the
Li, Danyang, Zhao, Youqun, Lin, Fen, Zhang, Chenxi, Yu, Song
An Analytical Method to Study Control Strategy of Torque-Vectoring Transmissions for Electric Vehicles Using MATLAB Simulink2024-28-021012/5/2024
Torque vectoring offers drive flexibility and continuous individual wheel torque regulation, which is unavailable in conventional transmission systems. Electric vehicles with multiple drivetrains and torque-vectoring system can significantly enhance vehicle response and handling, and thus the active safety, efficiency, and performance of the vehicle in all driving conditions. The current methodology of predicting performance characteristics is limited through slip rate calculations and yaw rate calculations. The vehicle dynamic performance evaluations with above said methodologies holds good for dynamic cornering. But in the scenarios where the vehicle moving in straight drive with different wheel traction requirements on either side (split-μ condition) and that requires torque vectoring. These above methods do not help to evaluate the performance of vehicle. Because these methodologies are based on predicting dynamic center-of-gravity values of vehicle. In the proposed methodology
Ramakrishnan, Gowtham Raj, Baheti, Palash
Fast Time-Varying Uncertainty Resisting for Hybrid UAV by Hierarchical Yaw Control with Constrained Input2024-01-700111/15/2024
Yaw control for aircraft using the rudder faces challenges in resisting fast time-varying uncertainty due to the relatively slower response of the rudder. In hybrid unmanned aerial vehicles equipped with both rudders and rotors, the introduction of powered yaw control offers novel solutions for addressing fast time-varying uncertainty by leveraging the quicker response of rotors compared to traditional rudders. This paper presents a hierarchical yaw control approach for hybrid unmanned aerial vehicles, comprising a nominal control for rudders to achieve the desired yaw tracking and a constrained powered yaw control for rotors to resist fast time-varying uncertainty. Given the constrained amplitude of powered yaw control, it is imperative that the designed auxiliary input guarantees adherence to its constraint. Firstly, a nonlinear control for nominal hybrid unmanned aerial vehicle system is formulated to deal with the nonlinearity model, rendering a modest nominal control for rudders
Dai, Jiawen, Liu, Jiaojiao, Yang, Yi, Bai, Jie, Zhang, Zheshuo
Evaluation of an Unsteady Yaw, Gust, and Broadband Turbulence Generation System for Closed-Loop Automotive Wind Tunnels15-18-01-000510/25/2024
This study investigates the flow characteristics in the test section of a model-scale, three-quarters open-jet, closed-loop return wind tunnel equipped with a novel device featuring three subsystems to generate transient yaw, gusts, and turbulence. The effect of each subsystem on the resulting turbulent and unsteady flows is evaluated individually and simultaneously. It is demonstrated that this new turbulence generation system can generate yaw distributions with standard deviations ranging from 2.1° to 8.0°. This replicates a wide range of on-road yaw behavior. Additionally, the subsystems can activate transient yaw events and unsteady gusts. Frequency sweeping was demonstrated to fill a wide range of low-frequency spectra, which helps recreate the on-road flow spectra in wind tunnels. Unsteady gusts of more than 15% of the mean flow velocity were achieved. The active turbulence subsystem generates turbulence levels from a few percent, passively, to over 20% intensity levels actively
Cacho, Gemiel, Marques, Joshua, Van Every, David, Waudby-Smith, Peter, Hanson, Ronald
Integrated Control of Intelligent Vehicle Driving Stability Using Three-Dimensional Phase Space10-09-01-000210/16/2024
To enhance vehicle dynamic stability during driving, we developed a three-dimensional phase space model that incorporates the sideslip angle of center of mass, yaw rate, and lateral load transfer rate. This model enabled real-time evaluation and active control of vehicle stability. First, longitudinal and lateral controllers were implemented to ensure precise vehicle trajectory. Second, a hierarchical control strategy was designed to actively manage the desired sideslip angle, yaw rate, and roll angle based on the vehicle’s destabilizing conditions, thereby maintaining the vehicle within a stable state space. We simulated and tested the stability analysis methods and integrated control strategies for both cars and trucks under DLC (double lane change) and CDC (circular driving condition) scenarios using joint simulations with CarSim/TruckSim and Simulink. The proposed integrated stability control strategy, which combined MPC-based trajectory tracking with direct yaw moment control and
Lai, Fei, Xiao, Hao, Huang, Chaoqun
Integrated Motion Control Strategy Considering Parameter Robustness for Distributed Vehicle by Wire10-08-04-003110/10/2024
To address the issues of functional conflicts in execution subsystems and the deterioration of control performance due to model parameter uncertainties in the motion control of distributed vehicle by wire, this article proposes an integrated control strategy considering parameter robustness. This strategy aims to compensate for model mismatch, resolve functional conflicts, and achieve motion coordination. Based on the over-actuation characteristics of distributed vehicle by wire, this article constructs the dynamic model and utilizes the tire cornering properties along with phase portraits to delineate the working regions of the execution subsystems. To deal with model parameter uncertainties and mismatch, tube-based model predictive control (tube-based MPC) is applied to the control strategy design, which compensates for model deviations through state feedback and constructs a robust positively invariant set (RPI) to constrain the system state. Correspondingly, the weights of control
Chen, Guoying, Bi, Chenxiao, Zhao, Xuanming, Yang, Liunan, Tang, Zhuo, Yu, Huili
Vehicle Yaw Stability Model Predictive Control Strategy for Dynamic and Multi-Objective Requirements2024-01-23244/9/2024
Vehicle yaw stability control (YSC) can actively adjust the working state of the chassis actuator to generate a certain additional yaw moment for the vehicle, which effectively helps the vehicle maintain good driving quality under strong transient conditions such as high-speed turning and continuous lane change. However, the traditional YSC pursues too much driving stability after activation, ignoring the difference of multi-objective requirements of yaw maneuverability, actuator energy consumption and other requirements in different vehicle stability states, resulting in the decline of vehicle driving quality. Therefore, a vehicle yaw stability model predictive control strategy for dynamic and multi-objective requirements is proposed in this paper. Firstly, the unstable characteristics of vehicle motion are analyzed, and the nonlinear two-degree-of-freedom vehicle dynamics models are established respectively. Secondly, the vehicle yaw stability control strategy is designed: The two
Wang, Hanlin, Wu, Jian, Chen, Zhicheng, He, Rui, Li, Haiqiao
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