Denso Corporation

Youichiro Suzuki

Takatoshi Sekizawa

Kenichirou Sanji

Naohito Takasuka

A distance estimation device includes a mobile terminal transmitting a radio wave and an in-vehicle device. The in-vehicle device includes a direction determination unit having a receiver, a distance measurement unit, and a correction unit. The receiver receives the radio wave and is arranged on a side of the vehicle. The direction determination unit determines a direction from which the radio wave comes based on a signal strength of the received radio wave. The distance measurement unit receives the radio wave and measures a distance from an installation position of the distance measurement unit to the mobile terminal based on information other than a signal strength of the received radio wave. The correction unit corrects the measured distance to be a distance from an edge of the vehicle to the mobile terminal based on the determined direction and the installation position.

Distance estimation device and distance estimation system

A tire device has a tire side device and a vehicle body side system, and determines a road surface condition and detects a tire wear state. The tire side device includes a vibration detection unit that outputs a detection signal according to a magnitude of a tire vibration, a control unit extracts a feature amount during one rotation of the tire, and a first data communication unit that transmits a road surface data including a feature amount. The vehicle body side system includes a second data communication unit that receives road surface data, a road surface determination part that determines a road surface condition based on the road surface data, an integral calculation part that calculates an integral value of the feature amount in a specific frequency band included in the road surface data, and a wear determination part that detects the tire wear state from the integral value.

Tire device

A control unit of a tire side device has a feature amount extraction part, a feature amount storage part, a change determination part, a vehicle speed estimation part, and an algorithm switching part. The change determination part determines whether or not there is a change in the road surface condition based on a present feature amount and a previous feature amount stored in the feature amount storage part, and transmits a road surface data including the present feature amount when there is a change in the road surface condition. The algorithm switching part switches based on the vehicle speed estimation by the vehicle speed estimation part whether to transmit the road surface data from the transmission unit when the road surface condition is changed, or to transmit the road surface data without determining whether or not the road surface condition is changed by the change determination part.

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Nisshin, Japan

Youichiro Suzuki