Road condition monitoring system
First Claim
1. A road condition monitoring system comprising:
- an acceleration sensor for detecting an acceleration of a vehicle and producing a signal corresponding thereto;
conversion means for receiving said signal from said acceleration sensor and converting said signal into one of at least two predetermined values in response to a magnitude of said acceleration every cycle of a predetermined time period;
summing means for summing up said one of at least two predetermined values in a predetermined number of consecutive cycles to provide a total value in the last cycle thereof;
memory means for storing the total value provided by said summing means; and
determination means for selecting one of at least two standard values in response to the condition of increase or decrease of the total value in the present cycle provided by said summing means as compared with the total value in the previous cycle stored in said memory means, said determination means comparing the total value in the present cycle with said one of at least two standard values to produce a road condition signal corresponding to a result of comparison.
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Accused Products
Abstract
The invention is directed to an arrangement for monitoring a road condition which determines the coefficient of friction of the road surface on the basis of a signal corresponding to an acceleration of a vehicle detected by an acceleration sensor. The signal is converted into one of at least two predetermined values by conversion means in response to a magnitude of the acceleration every cycle of a predetermined time period. The converted value is summed up by summing means by a predetermined number of consecutive cycles to provide a total value in the last cycle thereof which is stored in memory means. Then, in determination means, one of at least two standard values is selected in response to the condition of increase or decrease of the total value in the present cycle provided by the summing means as compared with the total value in the previous cycle stored in the memory means. And, the total value in the present cycle is compared with the above one of at least two standard values to produce a road condition signal corresponding to a result of comparison which represents the coefficient of friction of the road surface. The present system is applicable to an anti-skid control system for an automotive vehicle.
22 Citations
6 Claims
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1. A road condition monitoring system comprising:
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an acceleration sensor for detecting an acceleration of a vehicle and producing a signal corresponding thereto; conversion means for receiving said signal from said acceleration sensor and converting said signal into one of at least two predetermined values in response to a magnitude of said acceleration every cycle of a predetermined time period; summing means for summing up said one of at least two predetermined values in a predetermined number of consecutive cycles to provide a total value in the last cycle thereof; memory means for storing the total value provided by said summing means; and determination means for selecting one of at least two standard values in response to the condition of increase or decrease of the total value in the present cycle provided by said summing means as compared with the total value in the previous cycle stored in said memory means, said determination means comparing the total value in the present cycle with said one of at least two standard values to produce a road condition signal corresponding to a result of comparison. - View Dependent Claims (2, 3, 4)
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5. A road condition monitoring system comprising:
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an acceleration sensor for detecting an acceleration of a vehicle and producing a signal corresponding thereto; conversion means for receiving said signal from said acceleration sensor and converting said signal into one of three predetermined values in response to a magnitude of said acceleration every cycle of a predetermined time period; summing means for summing up said one of three predetermined values in a predetermined number of consecutive cycles and providing a total value in the last cycle thereof; memory means for storing the total value provided by said summing means; and determination means for providing a first high standard value, a first low standard value, a second high standard value higher than said first high standard value, and a second low standard value higher than said first low standard value, and determining the condition of increase or decrease of the total value in the present cycle provided by said summing means as compared with the total value in the previous cycle stored in said memory means, wherein said determination means compares the total value in the present cycle with said first high and low standard values, when the total value in the present cycle decreases, to produce a first road condition signal in case of being higher than said first high standard value, a second road condition signal in case of getting lower than said first high standard value, and a third road condition signal in case of getting lower than said first low standard value, and wherein said determination means compares the total value in the present cycle with said second high and low standard values, when said total value in the present cycle increases, to produce said first road condition signal in case of exceeding said second high standard value, said second road condition signal in case of exceeding said second low standard value, and said third road condition signal in case of being lower than said second low standard value, and produce a road condition signal determined on the basis of the total value in the previous cycle when the total value in the present cycle is the same as the total value in the previous cycle. - View Dependent Claims (6)
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Specification