ROAD SURFACE CONDITION ESTIMATING METHOD, ROAD SURFACE CONDITION ESTIMATING TIRE, ROAD SURFACE CONDITION ESTIMATING APPARATUS, AND VEHICLE CONTROL APPARATUS
First Claim
1. A road surface condition estimating method comprising:
- detecting the vibration of a tire of a running vehicle;
dividing the detected tire vibration into vibration in a pre-trailing domain, the domain existing before a trailing edge position, and vibration in a post-trailing domain, the domain existing after a trailing edge position, and at the same timeextracting signals of tire vibration in the pre-trailing domain or signals of tire vibration in a time range corresponding to the pre-trailing domain;
obtaining a frequency spectrum by analyzing the frequencies of the extracted signals; and
thereaftercalculating a vibration level in a predetermined frequency band from the obtained frequency spectrum; and
estimating a road surface condition based on the calculated vibration level.
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Abstract
The vibration of a tire 10 of a running vehicle in the circumferential direction or the width direction is detected by a road surface condition estimating tire 10, provided with an acceleration sensor 11 and a signal processing unit 12. Data of a detected vibration waveform are divided into data of three domains, namely, a pre-leading domain, a contact patch domain, and a post-trailing domain, and then the vibration levels in the pre-leading domain and the contact patch domain, respectively, are extracted. At the same time, a vibration component in a low-frequency band and a vibration component in a high-frequency band are extracted respectively from the vibration levels in the respective domains, and respective vibration level ratios R, which are each a ratio thereof, are calculated. Then, on the vehicle body side, the condition of a road surface on which the vehicle is running is estimated, based on the calculated vibration level ratio R and a map 32M, stored in a storage means 32, showing a relationship between the vibration level ratio R of tire vibration and road surface conditions. Thus a road surface condition can be estimated with accuracy even when there are changes in temperature or vehicle speed.
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Citations
45 Claims
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1. A road surface condition estimating method comprising:
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detecting the vibration of a tire of a running vehicle; dividing the detected tire vibration into vibration in a pre-trailing domain, the domain existing before a trailing edge position, and vibration in a post-trailing domain, the domain existing after a trailing edge position, and at the same time extracting signals of tire vibration in the pre-trailing domain or signals of tire vibration in a time range corresponding to the pre-trailing domain; obtaining a frequency spectrum by analyzing the frequencies of the extracted signals; and
thereaftercalculating a vibration level in a predetermined frequency band from the obtained frequency spectrum; and estimating a road surface condition based on the calculated vibration level. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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2. A road surface condition estimating method comprising:
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detecting the vibration of a tire of a running vehicle; dividing the detected tire vibration into vibration in a pre-trailing domain, the domain existing before a trailing edge position, and vibration in a post-trailing domain, the domain existing after a trailing edge position, and at the same time extracting signals of tire vibration in the pre-trailing domain or signals of tire vibration in a time range corresponding to the pre-trailing domain; obtaining a time-series waveform of tire vibration including only the frequencies in a predetermined frequency range by passing the extracted signals through a band-pass filter of the predetermined frequency band; and
thereaftercalculating a vibration level in the predetermined frequency band from the obtained time-series waveform of tire vibration; and estimating a road surface condition based on the calculated vibration level. - View Dependent Claims (11)
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26. A road surface condition estimating tire comprising:
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a tire vibration detecting means disposed on the air chamber side of an inner liner in a tire tread area, the tire vibration detecting means detecting the vibration of a tire of a running vehicle; and a signal extracting means for extracting signals of the pre-trailing domain of the tire vibration detected by the tire vibration detecting means. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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Specification