Maximization of Total Tangential Force Based on Rear-Front Driving Torque Distribution Control

Takane Akiyama･Yuki Yokokura･Kiyoshi Ohishi (Nagaoka University of Technology)･Jun-Ichi Fukui･Kenta Tatsuda･Yasumasa Imamura･Hirotaka Mochizuki (Mazda)

For both vehicle safety and operability, maintaining the vehicle's optimal total tangential force in response to the varying relationship between the tyre and the road surface is crucial. Particularly in All-Wheel-Drive (AWD) vehicles with independent front and rear drives, the flexibility of the front-rear drive force distribution ratio achieves this goal. This study investigates a drive-force distribution control method that maximises the sum of the tangential forces of the front and rear wheels, with the AWD vehicle as the control object.

Study on road friction information for next-generation road traffic safety
-Construction of new system to improve measurement procedures and accuracy-

Ichiro Kageyama (Consortium on Advanced Road-Friction Database)･Atsushi Watanabe･Yukiyo Kuriyagawa･Tetsunori Haraguchi (Nihon University)･Tetsuya Kaneko (Oosaka Sangyo University)･Minoru Nishio (Absolute)

Road friction information is crucial for ensuring the safety of autonomous driving and ADAS-equipped vehicles, and this information is considered essential, especially on snowy and icy roads in winter. In this study, we have been continuously measuring this road friction information, and we have now constructed a new measurement system to simplify the measurement procedure and improve measurement accuracy for wider-area measurements. This presentation will describe the overview of the system and provide examples of measurement results.

Estimation of Grip Margin and Road μ focusing on Motor Drive System Vibration

Eiichi Ono･Norio Yonezawa (Toyota Central R&D Labs.)･Tadakatsu Koyabu (DENSO)

The resonance phenomenon observed in wheel speed varies depending on the road surface friction condition. By utilizing this characteristic, it becomes possible to estimate the grip margin and the road surface friction coefficient (μ). In this paper, we propose an estimation method that makes use of the driveshaft resonance phenomenon in motor-driven vehicles. Furthermore, experimental verification of road surface μ estimation will be conducted on a proving ground where road surface μ is controlled.

Measurement of Three-Component Force Distribution in a Tire Contact Patch during Steering at Standstill Using Tread-Block Scanning

Tomonori Sakai (Honda R&D)･Masami Matsubara･Shuto Shimizu (Waseda University)

During steering at standstill, significant shear deformation occurs within the tire contact patch, resulting in a complex distribution of friction forces between the tread blocks and the road surface. In this study, we proposed a scanning measurement method capable of measuring contact forces at the tread block level, with the aim of elucidating the mechanical behavior within the tire contact patch during steering at standstill.

Loosening Progression of Wheel Nuts at Zero Axial Force

Takanobu Kawano･Ayako Okamoto･Yusuke Kimura (SOKEN)･Takahiro Tsuji･Yosuke Kimura (Toyota Motor)･Moe Suzuki (SOKEN)

The progression of loosening after the loss of clamping force in wheel fastening systems remains unclear, despite its importance for preventing tire detachment accidents. In this study, a tire test rig was used to measure the behavior of a nut under zero axial force conditions. The results indicate that an unloaded nut repeatedly contacts and separates from the wheel hole during tire rotation, thereby generating a force acting in the rotational direction of the nut, which may contribute to the progression of loosening.