路面摩擦係数推定によるアクティブ四輪操舵車両のプロテクション機能

摘要

A steering command from the driver to an active steering vehicle can be excessive, especially in lower road friction conditions. The present paper discusses protection functions for active steering vehicles. The grip margin is defined as the residual tire force normalized by the radius of friction circle. The isotropic brush model is reanalyzed so that a cubic equation for the estimation of the grip margin can be obtained. A protection function similar to that used in fly-by-wire aircraft is developed for active steering. This protection continuously updates the upper bound for a steering command according to the present vehicle state and the estimated grip margin. The proposed scheme is simulated using CarSim and the numerical results show their basic functionalities.%路面状態の変動は走行の不安定化や事故の原因となrnりやすく，路面摩擦係数の推定にはアクティブ操舵やrn各種の予防安全技術への大きな寄与が期待できrnる．このような方向の先行研究として，ブラシモrnデルを用い，タイヤに作用する制駆動力，横力，輪荷rn重，セルフアライニングトルクなどからグリップマーrnジンを経由する路面摩擦係数の推定手法が提案されてrnいる．