Browse Topic: Yaw

Items (818)

Optimal Torque Vectoring Control for Autonomous Electric Vehicles Considering Ride Comfort

2025-01-8310

04/01/2025

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

Coordinated Control Strategy for Longitudinal, Lateral, and Vertical Motions of Distributed Electric Vehicles Based on Model Predictive Control

2025-01-8300

04/01/2025

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

Investigation of Flow Structures in Different Body Types Contributing to Drag Change Due to Crosswind

2025-01-8767

04/01/2025

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

Study on Emergency Obstacle Avoidance Lateral Stability Control of Tractor Semitrailer Vehicles

2025-01-8296

04/01/2025

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

On the Critical Importance of Physical Modelling for the Analysis of Coast-Down Data

2025-01-8774

04/01/2025

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 Data

2025-01-8778

04/01/2025

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

Design Parameter Impact of Wind-Averaged Drag Optimization

2025-01-8772

04/01/2025

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

A Torque Distribution Strategy for the Six-Wheeled Lunar Rover

2025-01-8308

04/01/2025

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

A Sled Test Methodology for 25% Offset Crash Tests

2025-01-8737

04/01/2025

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

Aerodynamic Effect on Vehicle Handling

2025-01-8754

04/01/2025

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

YRSRA: Yaw and Roll Stable Region Analytics for Ground Vehicle System with 5G-V2X

2025-01-8799

04/01/2025

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

Investigation of Skin Friction Topology on the AeroSUV Using GLOF Meter

2025-01-8782

04/01/2025

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

Stability Control for Distributed Drive Electric Vehicles Using Particle Filter and Fuzzy Integral Sliding Mode Control

2025-01-8811

04/01/2025

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

Direct Yaw Moment Control for Distributed Drive Electric Vehicles Based on Full-Order Terminal Sliding Mode

2025-01-7024

01/31/2025

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 Control

10-09-02-0010

01/24/2025

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 Mode

2024-01-7048

12/13/2024

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 Simulink

2024-28-0210

12/05/2024

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 Input

2024-01-7001

11/15/2024

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 Tunnels

15-18-01-0005

10/25/2024

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 Space

10-09-01-0002

10/16/2024

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 Wire

10-08-04-0031

10/10/2024

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

A Novel Torque Distribution Approach of Four-Wheel Independent-Drive Electric Vehicles for Improving Handling and Energy Efficiency

2024-01-2315

04/09/2024

This paper presents a torque distribution strategy for four-wheel independent drive electric vehicles (4WIDEVs) to achieve both handling stability and energy efficiency. The strategy is based on the dynamic adjustment of two optimization objectives. Firstly, a 2DOF vehicle model is employed to define the stability control objective for Direct Yaw moment Control (DYC). The upper-layer controller, designed using Linear Quadratic Regulator (LQR), is responsible for tracking the target yaw rate and target sideslip angle. Secondly, the lower-layer torque distribution strategy is established by optimizing the tire load rate and motor energy consumption for dynamic adjustment. To regulate the weights of the optimization targets, stability and energy efficiency allocation coefficient is introduced. Simulation results of double lane change and split μ road conditions are used to demonstrate the effectiveness of the proposed DYC controller.

Dou, Jingyang, Chen, Zixuan, Zhang, Yunqing, Wu, Jinglai

On the Investigation of Car Steady-State Cornering Equilibria and Drifting

2024-01-2764

04/09/2024

This paper proposes a thorough investigation of steady-state cornering equilibria for cars. Besides equilibria corresponding to normal driving behaviour - herein denoted as stable-normal turn, drifting is attracting increasing attention. When discussing drifting, it is typically assumed that yaw rate and steering angle have opposite signs, i.e. the driver is countersteering, and the rear axle is saturated. Interestingly, another unstable equilibrium is possible, herein referred to as unstable-normal turn. In this work, an attempt to give a comprehensive definition of drift is made. An inverse model is proposed to compute the driver inputs needed to perform a steady-state turn for a given radius and sideslip angle. The mathematical meaning of all equilibria is explored by linearizing the system and analyzing eigenvalues and eigenvectors of the resulting state matrices.

Righetti, Giovanni, Binetti, Elisabetta, Pinto de Castro, Ricardo, Lot, Roberto, Massaro, Matteo, Lenzo, Basilio

Vehicle Yaw Dynamics Safety Analysis Methodology based on ISO-26262 Controllability Classification

2024-01-2766

04/09/2024

Complex chassis systems operate in various environments such as low-mu surfaces and highly dynamic maneuvers. The existing metrics for lateral motion hazard by Neukum [13] and Amberkar [17] have been developed and correlated to driver behavior against disturbances on straight line driving on a dry surface, but do not cover low-mu surfaces and dynamic driving scenarios which include both linear and nonlinear region of vehicle operation. As a result, an improved methodology for evaluating vehicle yaw dynamics is needed for safety analysis. Vehicle yaw dynamics safety analysis is a methodical evaluation of the overall vehicle controllability with respect to its yaw motion and change of handling characteristic. The yaw dynamics safety analysis is crucial for understanding how a driver-vehicle system responds to disturbances (external forces such as failure modes) in various driving scenarios and maneuvers., and it plays a significant role in evaluating the overall safety and performance of

paik, Scott, Almasri, Hossam, Rao Medidha, Neelakanta, Capobianco, Anthony, Evans, Andrew, Sevillano, Yvette

Vehicle Yaw Stability Model Predictive Control Strategy for Dynamic and Multi-Objective Requirements

2024-01-2324

04/09/2024

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

A MPC based Cooperated Control Strategy for Enhanced Agility and Stability of Four-Wheel Steering and Drive Electric Vehicles

2024-01-2768

04/09/2024

Multiple actuators equipped in electric vehicles, such as four- wheel steering (4WS) and four-wheel drive (4WD), provide more degrees of freedom for chassis motion control. However, developing independent control strategies for distinct actuator types could result in control conflicts, potentially degrading the vehicle's motion performance. To address this issue, a model predictive control (MPC) based steering-drive cooperated control strategy for enhanced agility and stability of electric vehicles with 4WD and 4WS is proposed in this paper. By designing the control constraints within the MPC framework, the strategy enables single-drive control, single-steering control, and steering-drive cooperative control. In the upper control layer, a linear time-varying MPC (LTV-MPC) is designed to generate optimal additional yaw moment and additional steering angles of front and rear wheels to enhance vehicle agility and lateral stability. In the lower control layer, a linear MPC (LMPC) based

Sun, Haobo, Zhang, Lin, Zhao, Chunlai, Wang, Nian, Zhang, Zeyang, Chen, Hong

Dynamic Yaw Rate Regulation for Moderate Understeer in Four-Wheel Steering Vehicles with Zero Sideslip Angle

2024-01-2516

04/09/2024

The pursuit of maintaining a zero-sideslip angle has long driven the development of four-wheel-steering (4WS) technology, enhancing vehicle directional performance, as supported by extensive studies. However, strict adherence to this principle often leads to excessive understeer characteristics before tire saturation limits are reached, resulting in counter-intuitive and uncomfortable steering maneuvers during turns with variable speeds. This research delves into the phenomenon encountered when a 4WS-equipped vehicle enters a curved path while simultaneously decelerating, necessitating a reduction in steering input to adapt to the increasing road curvature. To address this challenge, this paper presents a novel method for dynamically regulating the steady-state yaw rate of 4WS vehicles. This regulation aims to decrease the vehicle's sideslip angle and provide controlled understeer within predetermined limits. As a result, the vehicle can maintain a zero-sideslip angle during turns with

Guan, Yihang, Zhou, Hongliang, Jing, Houhua, Miao, Weiwei

Improving Vehicle Stability and Comfort through Active Corner Positioning

2024-01-2552

04/09/2024

The emergence of new electric vehicle (EV) corner concepts with in-wheel motors offers numerous opportunities to improve handling, comfort, and stability. This study investigates the potential of controlling the vehicle's corner positioning by changing wheel toe and camber angles. A high-fidelity simulation environment was used to evaluate the proposed solution. The effects of the placement of the corresponding actuators and the actuation point on the force required during cornering were investigated. The results demonstrate that the toe angle, compared to the camber angle, offers more effect for improving the vehicle dynamics. The developed direct yaw rate control with four toe actuators improves stability, has a positive effect on comfort, and contributes to the development of new active corner architectures for electric and automated vehicles.

Skrickij, Viktor, Šabanovič, Eldar, Kojis, Paulius, Žuraulis, Vidas, Ivanov, Valentin, Shyrokau, Barys

Coordinated Control of Trajectory Tracking and Yaw Stability of a Hub-Motor-Driven Vehicle based on Four-Wheel-Steering

2024-01-2767

04/09/2024

In order to improve the trajectory tracking accuracy and yaw stability of vehicles under extreme conditions such as high speed and low adhesion, a coordinated control method of trajectory tracking and yaw stability is proposed based on four-wheel-independent-driving vehicles with four-wheel-steering. The hierarchical structure includes the trajectory tracking control layer, the lateral stability control decision layer, and the four-wheel angle and torque distribution layer. Firstly, the upper layer establishes a three-degree-of-freedom vehicle dynamics model as the controller prediction model, the front wheel steering controller is designed to realize the lateral path tracking based on adaptive model predictive control algorithm and the longitudinal speed controller is designed to realize the longitudinal speed tracking based on PID control algorithm. Then, the middle layer decides the rear wheel steering angle and the additional yaw moment to maintain the vehicle's yaw stability based

Fu, Yao, Xie, Renmin, Kaku, Chuyo, Zheng, Hongyu

Real-Time Cornering Stiffness Estimation and Road Friction State Classification under Normal Driving Conditions

2024-01-2650

04/09/2024

The tire cornering stiffness plays a vital role in the functionality of vehicle dynamics control systems, particularly when it comes to stability and path tracking controllers. This parameter relies on various external variables such as the tire/ambient temperature, tire wear condition, the road surface state, etc. Ensuring a reliable estimation of the cornering stiffness value is crucial for control systems. This ensures that these systems can accurately compute actuator requests in a wide range of driving conditions. In this paper, a novel estimation method is introduced that relies solely on standard vehicle sensor data, including data such as steering wheel angles, longitudinal acceleration, lateral acceleration, yaw rate, and vehicle speed, among others. Initially, the vehicle's handling characteristics are deduced by estimating the understeer gradient. Subsequently, real-time estimates of the cornering stiffness values are derived by adapting the previously obtained parameters

Balaga, Sanjay Raghav, labella, Mario, Singh, Kanwar Bharat

Compatibility between Handling Agility and Stability of Vehicle using Rear Wheel Steering with Dual-Link Actuators

2024-01-2761

04/09/2024

The experimental control findings of increasing the handling performance so that the yaw motion of the vehicle is nimble and stable utilizing the upgraded rear wheel steering system equipped with dual-link actuators are shown in this work. In most automobiles, the steering axis is well defined in front suspension. However, unless the vehicle's rear suspension is a sort of double wishbone, the steering axis is not clearly defined in regular multi-link rear suspensions. As a result, most current automobiles have a suspension geometry feature in which the camber and toe angles change at the same time when the assist link is changed to steer the back wheels. To create lateral force from the rear tire while preserving maximum tire grip, the dual-link actuators control for modifying the strokes of suspension links must keep the camber angle constant and adjust only the toe angle. The relationship between the motion of two suspension link actuators and the camber angle/toe angle is found in

Park, Jaeyong, Na, Sungsoo

Research on the Control Strategy for Handling Stability of Electric Power Steering System with Active Front Wheel Steering Function

10-08-01-0006

02/07/2024

Due to the presence of uncertain disturbances in the actual steering system, disturbances in the system may affect the handling stability of the vehicle. Therefore, this article proposes an integrated steering system control strategy with stronger anti-disturbance performance. When disturbances exist in the system, the proposed control strategy effectively reduces the attitude changes during the vehicle steering process. In the upper-level control strategy, a variable transmission ratio curve is designed to coordinate the high-speed handling stability and low-speed steering sensitivity of the vehicle. On this basis, a sideslip angle observer is proposed based on the extended state observation theory, which does not depend on an accurate system model, thus determining the intervention timing of the active front wheel steering system. In the lower-level control strategy, DR-PI/DR-PID controllers are designed for the integrated steering system. Finally, experiments are conducted in the

Wei, JinCheng, Zheng, Zhu’An, Chen, JiaLing

Integrated Four-Wheel Steering and Direct Yaw-Moment Control for Autonomous Collision Avoidance on Curved Road

02-17-01-0007

01/25/2024

An automatic collision avoidance control method integrating optimal four-wheel steering (4WS) and direct yaw-moment control (DYC) for autonomous vehicles on curved road is proposed in this study. Optimal four-wheel steering is used to track a predetermined trajectory, and DYC is adopted for vehicle stability. Two single lane change collision avoidance scenarios, i.e., a stationary obstacle in front and a moving obstacle at a lower speed in the same lane, are constructed to verify the proposed control method. The main contributions of this article include (1) a quintic polynomial lane change trajectory for collision avoidance on curved road is proposed and (2) four different kinds of control method for autonomous collision avoidance, namely 2WS, 2WS+DYC, 4WS, and 4WS+DYC, are compared. In the design of DYC controller, two different feedback control methods are adopted for comparison, i.e., sideslip angle feedback and yaw rate feedback. The simulation results demonstrate significant

Lai, Fei

Virtual Brake Pull Maneuver Development

2023-36-0021

01/08/2024

The Brake Pull phenomena is the directional deviation when a strong deceleration is applied, this happens due to asymmetries in the vehicle with diverse origins: dimensional, stiffness, damping, friction and loading condition. This phenomenon creates the necessity of driver inputs on the steering wheel adjusting the vehicle direction to keep the straight line. Great part of asymmetries in the vehicle is avoidable due to building quality, correct maintenance, and others. However, an unequal loading condition on the transversal direction of the vehicle is very common: the vehicle occupied only by the driver is a usual condition. This circumstance creates a load asymmetry that can induces the brake pull phenomena. This study aims to create and validate a virtual toll capable of representing the brake pull phenomena caused by a loading asymmetry. A vehicle modeled in multibody dynamics technique representing the vehicle mass inertias, suspension mechanisms kinematics, tire behavior and

Terra, Rafael Tedim

Semi-Active Control Strategy of Shimmy of Straddle-Type Monorail Vehicle and Its Effectiveness Analysis

2023-01-7076

12/31/2023

As an important way of energy saving and environmental protection, the lateral stability of straddle-type monorail vehicle (STMV) has attracted more and more attention. In order to solve this problem, a semi-active lateral control strategy of STMV dynamic model based on magnetorheological fluid damper is proposed. The inverse model of magnetorheological damper is constructed by neural network. An adaptive neural fuzzy algorithm for STMV dynamic model based on body acceleration and velocity feedback is designed, and its feasibility is verified by Kalman filter method. Through the simulation comparison of lateral acceleration and yaw angular acceleration, the control method has good measurement accuracy and can meet the needs of practical engineering measurement. It provides a method and basis for the stability and effectiveness of STMV swing semi-active control.

Zhou, Junchao, Huang, Shangwu, Gao, Jianjie

Bi-stability of the Wake Flow of a Hatchback Car under Zero Yaw Angle Condition

15-17-02-0007

12/09/2023

The aerodynamic performance of automobile especially drag and lift was largely determined by the wake flow, which is three-dimensional, unsteady, and turbulent. The styling of the rear back of the vehicle body has much influence on the wake flow structure, typically including squareback, notchback, and hatchback. Bi-stability of the wake flow of vehicle body makes the aerodynamic force oscillating, which affects the energy consumption and driving stability. This article investigates the bi-stability of wake flow of a hatchback SUV in full-scale automotive wind tunnel. Both aerodynamic force and surface pressure on the rear back of the vehicle were measured. Time series of aerodynamic force and pressure footprint are used to confirm the existence of bi-stability. The effects of some sensitive factors on the bi-stability have been analyzed. The results show that for the given condition with bi-stability phenomenon existing, the change of drag and lift can be 6.36% and 111%, respectively

Yuan, Haidong, Wang, Haiyang, Fan, Guangjun

Assisted Steering Control for Distributed Drive Electric Vehicles Based on Combination of Driving and Braking

2023-01-7012

10/30/2023

This paper presents a low-speed assisted steering control approach for distributed drive electric vehicles. When the vehicle is driven at low speed, the braking of the inner-rear wheel is combined with differential drive to reduce the turning radius. A hierarchical control structure has been designed to achieve comprehensive control. The upper-level controller tracks the expected yaw rate and vehicle side-slip angle through a Linear Quadratic Regulator (LQR) algorithm. The desired yaw rate and vehicle side-slip angle are obtained according to the reference vehicle model, which can be regulated by the driver through the accelerator pedal. The lower-level controller uses a quadratic programming algorithm to distribute the yaw moment and driving moment to each wheel, aiming to minimize tire load rate variance. Simulation and real vehicle tests compare three steering modes: front-wheel steering only, front-wheel steering + differential drive assisted steering, and front-wheel steering

Wu, Dongmei, Wang, Cheng, Du, Changqing, Zhang, Yichao

Analytical and Experimental Handling Performance of Ultra-Efficient Lightweight Vehicles

2023-24-0135

08/28/2023

The rising environmental awareness has led to a growing interest in electric and lightweight vehicles. Four-wheeled Ultra-Efficient Lightweight Vehicles (UELVs) have the potential to improve the quality of urban life, reduce environmental impact and make efficient use of land. However, the safety of these vehicles in terms of dynamic behaviour needs to be better understood. This paper aims to provide a quantitative assessment of the handling behaviour of UELVs. An analytical single-track model and a numerical simulation by VI-CarRealTime are analysed to evaluate the dynamic performance of a UELV compared to a city car. This analysis shows that the lightweight vehicle has a higher readiness (i.e. lower reaction time to yaw rate) for step steering and lower steering effort (i.e. higher steady-state value). Experimental analysis through real-time driving sessions on the Dynamic Driving Simulator assesses vehicle responses and subjective perception for different manoeuvres. The driving

Musso, Emanuele, Previati, Giorgio, Mastinu, Gianpiero

Frequency-Domain Analysis and Joint Torque Vibration Suppression Control on Two-Input-Two-Output Torque Difference Amplification Motor Drive System of Electrified Vehicles

10-07-03-0020

06/28/2023

To improve the cornering performance, a torque vectoring differential (TVD) that generates a torque difference between the left and right wheels has been developed. Particularly, the use of multiple electric traction motors can easily achieve this. A TVD with a two-motor-torque difference amplification mechanism (TDA-TVD), which employs a unique alignment of planetary gears, has been studied and it can generate a larger torque difference compared to an individual-wheel-drive (IWD) system in the case of using the equal torque output from the traction motors. However, due to the mechanically complicated driving force transmission system including driveshafts and planetary gears, TDA-TVD is prone to cause torsional vibrations of the driveshaft, and the yaw rate of the vehicle body while differential torque is generated. A previous study derived a dynamic model TDA-TVD and designed a vibration suppression feedforward controller. While the study demonstrated a certain vibration suppression

Fuse, Hiroyuki, Yu, Guangzhi, Fujimoto, Hiroshi, Sawase, Kaoru, Takahashi, Naoki, Takahashi, Ryota, Okamura, Yutaro, Koga, Ryosuke

Flow-Through Transducer for Wind Tunnel Analysis

TBMG-48250

06/01/2023

Existing integral flow-through balances have been limited to five-component force and moment measurements (normal and side force; pitch, yaw, and rolling moment) excluding a sixth desired force measurement: axial force. To enable key aerospace R&D applications, NASA’s Langley Research Center has developed a single-piece flow-through transducer design capable of measuring all six components adding in the Axial force measurement.

Reaction Rod Link in Rear Cab Suspension to Control Cab Dynamics in Tractor-Semitrailer Vehicles

02-16-04-0024

05/24/2023

Articulated vehicles form an important part of our society for the transport of goods. Compared to rigid trucks, tractor-trailer combinations can transport huge quantities of load without increasing the axle load. The fifth wheel (FW) acts as a bridge between the tractor and trailer, which can be moved within the range to achieve rated front and rear axle loads. When the FW is moved front, it adversely affects the cab dynamics and cab suspension forces. Compared to the cab pitch and roll, yaw motion increases drastically. The current study tries to address this issue by providing reaction rod links in the rear cab suspension. In this study, a 4×2 tractor with a three-axle semitrailer is considered by keeping the FW at its frontmost position, which is the worst-case scenario for a cab. Three different cases of reaction rod arrangement and its influence on cab dynamics are studied in comparison with a model without reaction rods. To assess this, time signal–based relative pseudo-fatigue

Bhat, Sindhoor

Experimental Investigation into Modulated Aeroacoustic Cabin Noise arising from Unsteady Flow Conditions

2025-01-002905/05/2023

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

The Influence of Traffic Wakes on the Aerodynamic Performance of Heavy Duty Vehicles

2023-01-0919

04/11/2023

Road vehicles have been shown to experience measurable changes in aerodynamic performance when travelling in everyday safe-distance driving conditions, with a major contributor being the lower effective wind speed associated with the wakes from forward vehicles. Using a novel traffic-wake-generator system, a comprehensive test program was undertaken to examine the influence of traffic wakes on the aerodynamic performance of heavy-duty vehicles (HDVs). The experiments were conducted in a large wind tunnel with four primary variants of a high-fidelity 30%-scale tractor-trailer model. Three high-roof-tractor models (conventional North-American sleeper-cab and day-cab, and a zero-emissions-cab style) paired with a standard dry-van trailer were tested, along with a low-roof day-cab tractor paired with a flat-bed trailer. Amongst these, trailer variants provided a total of 10 HDV configurations that were tested in uniform turbulent flow over a range of freestream yaw angles between ±15°, and

McAuliffe, Brian, Barber, Hali, Ghorbanishohrat, Faegheh

The Integrated Trajectory Tracking, Yaw Stability and Roll Stability Model Predictive Control for Autonomous Vehicle in Limited Handling Condition

2023-01-0667

04/11/2023

In the current literature, the research studies on the trajectory tracking control and stability control strategy for autonomous vehicles in limited condition mostly focus on the yaw plane control, but few of the studies have considered the combined control performance of trajectory tracking, yaw and roll stability, and the roll stability is critical under the extreme cornering condition for autonomous vehicles. Aiming at the above shortages, this study designs the model predictive control (MPC) strategy for the autonomous vehicles under the limited handling condition, which integrates the front and rear wheel active steering control, four-wheel independent drive and braking control and active suspension control to comprehensively improve the trajectory tracking accuracy, yaw plane stability and roll plane stability of the vehicle under the extreme condition. In the internal prediction model of the MPC, the yaw plane dynamics, roll plane dynamics and suspension system models are

Li, Boyuan, Li, Wenfei, Hua, Wei, Velenis, Efstathios

Modeling and Verification of Tire Nonlinearity Effect on Accuracy of Vehicle Yaw Rate Calculation

2023-01-0753

04/11/2023

The desired yaw rate is a vital target parameter for vehicle stability control, which is currently determined as a steady-state yaw rate by the linear single-track vehicle model. Tire nonlinearity deteriorates the effect of vehicle stability control at larger lateral acceleration. This paper proposes a new calculation method of the steady-state yaw rate considering the tire nonlinearity based on the brush tire model. To validate and verify the proposed method, step steering tests of the target vehicle under different lateral accelerations are carried out on a real proving ground. The results show that when the lateral acceleration is relatively small, the difference between the calculation results of the proposed method and the traditional one is not apparent, and both methods can provide a good estimation for the steady-state yaw rate; however, when the lateral acceleration is relatively large, the difference becomes apparent. It can be shown that the linear tire model cannot be able

Min, Delei, Wei, Yintao

Dynamic Switch Control of Steering Modes for 4WID-4WIS Electric Vehicle Based on MOEA/D Optimization

2023-01-0641

04/11/2023

To overcome the shortcoming that vehicles with multiple steering modes need to switch steering modes at parking or very low speeds, a dynamic switch method of steering modes based on MOEA/D (Multi-objective Evolutionary Algorithm Based on Decomposition) was proposed for 4WID-4WIS (Four Wheel Independent Drive-Four Wheel Independent Steering) electric vehicle, considering the smoothness of dynamic switch, the lateral stability of the vehicle and the energy economy of tires. First of all, the vehicle model of 4WID-4WIS was established, and steering modes were introduced and analyzed. Secondly, the conditions for the dynamic switch of steering modes were designed with the goal of stability and safety. According to different constraints, the control strategy was formulated to obtain the target angle of the active wheels. Then aiming at the smoothness of the dynamic switch, the active wheel angle trajectory was constructed based on the B-spline theory. And the MOEA/D algorithm was used to

Qiao, Yiran, Chen, Xinbo, Li, Ran

Optimal Torque-Vectoring Control Strategy for Energy Efficiency and Vehicle Dynamic Improvement of Battery Electric Vehicles with Multiple Motors

2023-01-0563

04/11/2023

Electric vehicles comprising multiple motors allow the individual wheel torque allocation, i.e. torque-vectoring. Powertrain configurations with multiple motors provide additional degree of freedom to improve system level efficiencies while ensuring handling performances and active safety. However, most of the works available on this topic do not simultaneously optimize both vehicle dynamic performance and energy efficiency while considering the real-time implementability of the controller. In this work, a new and systematic approach in designing, modeling, and simulating the main layers of a torque-vectoring control framework is introduced. The high level control combines the actions of an adaptive Linear Quadratic Regulator (A-LQR) and of a feedforward controller, to shape the steady-state and transient vehicle response by generating the reference yaw moment. A novel energy efficient torque allocation method is proposed as a low level controller. The torque is allocated on each wheel

Manca, Raffaele, Castellanos Molina, Luis MIguel, Hegde, Shailesh, Tonoli, Andrea, Amati, Nicola, Pazienza, Luigi

Combined Path Following and Vehicle Stability Control using Model Predictive Control

2023-01-0645

04/11/2023

This paper presents an innovative combined control using Model Predictive Control (MPC) to enhance the stability of automated vehicles. It integrates path tracking and vehicle stability control into a single controller to satisfy both objectives. The stability enhancement is achieved by computing two expected yaw rates based on the steering wheel angle and on lateral acceleration into the MPC model. The vehicle's stability is determined by comparing the two reference yaw rates to the actual one. Thus, the MPC controller prioritises path tracking or vehicle stability by actively varying the cost function weights depending on the vehicle states. Using two industrial standard manoeuvres, i.e. moose test and double lane change, we demonstrate a significant improvement in path tracking and vehicle stability of the proposed MPC over eight benchmark controllers in the high-fidelity simulation environment. The numerous benchmark controllers use different path tracking and stability control

Lenssen, Daan, Bertipaglia, Alberto, Santafe, Felipe, Shyrokau, Barys

Active Control of Front Wheel Steering Geometry Based on Nonlinear Three-Step Method

2022-01-7110

12/22/2022

With high integration, high efficiency and high flexibility, the front wheel independent Steer-by-Wire system (SbW) is a key link between autonomous vehicles and intelligent chassis technology, and is one of the current focused research in industry and academia. In this paper, a strategy for active control of steering geometry of the Steer-by Wire independent steering system is proposed based on the nonlinear three-step method and Ackermann geometry relationship with the control goal of improving the driving stability and handling performance of the vehicle. The control strategy takes the front wheel steering angle difference and yaw moment as the control variables, and tracks the expected side slip angle and yaw rate as the control objectives. A more accurate vehicle model, and a nonlinear tire model with a reference vehicle model, is used to design the three-step controller to improve the effectiveness of the steady-state control and reduce the system error. When designing the

Wang, Yifei, Wang, Fei, Li, Weifeng, Gao, Bingzhao, Meng, Dele, Tian, Mengjian

Research on Path Planning and Tracking Control for Automatic Emergency Steering of Intelligent Vehicle on Curved Road

2022-01-7108

12/22/2022

A warning MAP diagram method for automatic emergency steering of intelligent vehicle on curved road to avoid collision is proposed. Firstly, the path planning of emergency steering collision avoidance for vehicle on curved road is carried out, using fifth-degree and seventh-degree polynomials with the vehicle point mass model. Secondly, the vehicle lateral kinematic model is used for controller design to track the desired trajectory by Stanley control algorithm. Thirdly, the Carsim dynamics model is investigated with feedback control on lateral displacement and yaw angle of the vehicle, so as to correct the front wheel steering angle based on Stanley control algorithm. Finally, the simulation and analysis are carried out for the driving stability of the vehicle under different combinations of speed, road adhesion coefficient and obstacle distance. According to the predetermined thresholds of vehicle sideslip angle, yaw rate and lateral acceleration, the minimum safety distance required

Lai, Fei

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