PROBLEM TO BE SOLVED: To set an optimum assist ratio of steering and thereby improve the steering feeling of a driver.SOLUTION: An assist ratio computation device 100 of a power steering system according to the present invention comprises: a driving state acquisition unit 126 for acquiring a driving state that corresponds to a driving route on the basis of information pertaining to the current location of a vehicle and a destination place and an assist ratio acquisition unit 127 for acquiring an assist ratio that corresponds to the acquired driving state that corresponds to the driving route from a database 150 in which an assist ratio is defined for each driving state where the discrete degree of biological information associated with steering decreases.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2018,JPO&INPIT【課題】操舵のアシスト比を最適に設定することで運転者の操舵感を向上する。【解決手段】本発明に係るパワーステアリングシステムの操舵アシスト比演算装置100は、車両の現在地と目的地の情報に基づいて、運転経路に応じた運転状態を取得する運転状態取得部126と、ステアリング操舵に関連する生体情報の離散度が低くなるアシスト比を運転状態毎に規定したデータベース150から、取得した前記運転経路に応じた前記運転状態に応じたアシスト比を取得するアシスト比取得部127と、を備える。【選択図】図1
