Design and Implementation of a Tire Force Estimation Model Based on the Extended Kalman Filter

Shota Kitano･Hideki Itoga･Takanori Hibino･Kazuki Kuwabara･Hirotaka Kaneko (Toyota Motor)

From our previous report, it was found that combining an 8-degree-of-freedom vehicle model with an Extended Kalman Filter enables highly accurate estimation of tire forces. However, there is no clear method for determining the system covariance QQQ and observation covariance RRR, which significantly affect the accuracy of the Kalman Filter, and this topic generated considerable discussion during the Q&A session. In this presentation, we propose a method for determining QQQ and RRR by applying an optimization approach that utilizes the estimation error covariance and the observation prediction error covariance, thereby achieving sufficient accuracy.

Influence of Coupling Engagement Level in an Electronic AWD System on Planar and Vertical Vehicle Dynamics

Naoki Hiraga･Koki Yamamoto･Daichi Okazaki･Osamu Sunahara (Mazda)･Katsuya Ishii･Makoto Yamakado･Yoshio Kano･Masaki Yamamoto･Masato Abe (Kanagawa Institute of Technology)

In AWD vehicles equipped with an electronically controlled coupling, torque is transmitted through rotational constraint between the front and rear axles according to the level of longitudinal differential limiting generated by the coupling engagement. This mechanism influences the planar motion and the sprung-mass behavior of the vehicle. In this study, these effects are analyzed, and the effectiveness of a coupling control strategy coordinated with G-Vectoring Control is verified.

Influence of Brake G-Vectoring Control on Double Lane-Change Test Performance

Haruki MAJIMA･Ibuki GENPEI･Masato ABE･Yoshio KANO･Masaki YAMAMOTO･Makoto YAMAKADO (Kanagawa Institute of Technology)･Tomohisa SHIBATA･Yoichi MIZUNO (Toyota Motor)

The influence of Brake G-Vectoring Control on double lane-change test performance was evaluated. Full-scale tests based on ISO 3888-2 (elk test) were conducted, and differences in passing speed, steering operation, and vehicle motion with and without the control were compared. Improvements such as enhanced initial yaw response, contributing to a more intuitive steering feel(INOMAMA-KAN), were observed, indicating factors through which the control contributes to performance enhancement.

Development of an AI-based bushing dynamic stiffness prediction model to improve modeling efficiency for R&H simulations

MIREU KIM･TAEMIN JEONG (Hyundai Motor)

Recently, as AI technology has advanced, attempts to incorporate AI technology into the vehicle modeling process in the CAE field have increased. Previously, the static or dynamic characteristics of vehicle parts were expressed in the form of mathematical functions and substituted with equivalent models. However, this type of modeling technique has limitations in expressing the complex nonlinear dynamic characteristics of vehicle parts. Therefore, this paper proposes a new modeling technique by introducing AI technology to the existing modeling technique and shows that the efficiency of vehicle parts characteristic modeling can be improved.

AN INVESTIGATION OF REAL-TIME ESTIMATOR ON MAXIMUM TIRE GRIP FOR YAW MOMENT CONTROL

JAE YONG PARK･SUNG HO PARK (Hyundai Motor)

The research for determining a driving vehicle's maximal and current tire grip in real-time is presented in this paper. When driving at medium and low speeds, wheel slip is not a major issue for direct yaw moment control (DYC), which is dependent on sensing it. However, frequent wheel slips have a major negative impact on driving performance when driving a high-performance car at high speeds or on a racetrack. Because it is unable to produce more driving and steering force to the tire when it loses grip. Thus, driving performance can be greatly enhanced if the tire operating force of each wheel can be measured in real-time and the tire friction saturation limit can be accurately determined. In this study, a precise tire friction limit model is constructed to better limit driving handling performance using DYC, and the accuracy of the estimation on the current tire grip is validated using actual vehicle measurements.

Energy-Transmissibility-Based Transient Response Analysis of Vehicle Dynamics

TORU YAMAZAKI (Kanaga)･Atsushi Kosegawa (Graduate School of Kanagawa University)･Yudai Araki (Undergraduate of Kanagawa University)

This study extends a previously proposed energy transmissibility model from steady-state to transient vehicle dynamics. A three-degree-of-freedom model, consisting of lateral, yaw, and roll motions, is reformulated in the time domain so that power input, transfer, and dissipation can be tracked during maneuvers. Step and pulse steering inputs, as well as roll disturbances, are applied to evaluate the transient evolution of slip-angle, yaw-rate, and roll-energy states. The results clarify design trade-offs between agility and stability, linking steady and transient behavior, and illustrate how energy-based indices can guide early-stage tuning of mass, damping, and steering characteristics.

Design of an Integrated Steering-Suspension Corner Module

Haoyang Lv･Jianyuan Liu･Jingran Wang･Kaipeng Wang･Hongyuan Jiang･Zihong Zou･Zhouyi Zhen･Mingyan Hu･Mengjian Tian (Shenzhen Technology University)

The steering–suspension design of electric-drive corner modules faces an inherent kingpin parameter conflict: increasing scrub radius for high maneuverability compromises steering lightness and brake stability. This hinders simultaneous high maneuverability and high-speed stability. To address this, a novel dual-kingpin, two-stage integrated suspension steering mechanism is proposed. The primary kingpin is determined by a multi-link suspension, and the assembly, mounted on a supporting component, steers about the secondary kingpin via a crank-rocker linkage. ADAMS/Car simulation validates that the mechanism effectively balances large-angle maneuverability with high-speed stability.