Road-Surface Condition Estimating Device
First Claim
1. A road-surface condition estimating device comprising:
- driving-wheel-speed detecting means that detects a speed of a driving wheel;
driven-wheel-speed detecting means that detects a speed of a driven wheel;
driven-wheel-acceleration detecting means that detects an acceleration of the driven wheel;
driving-wheel-speed difference calculating means that calculates a difference between a currently detected driving wheel speed and a previously detected driving wheel speed as a driving-wheel-speed differencedriven-wheel-speed difference calculating means that calculates a difference between a currently detected driven wheel speed and a previously detected driven wheel speed as a driven-wheel-speed difference ;
acceleration difference calculating means that calculates a difference between a currently detected driven-wheel acceleration and a previously detected driven-wheel acceleration as a driven-wheel-acceleration difference;
ground-load calculating means that calculates a ground load acting on the driving wheel;
characteristic calculating means that calculates an amount of change in a road-surface friction coefficient with respect to an amount of change in a slip rate in a characteristic curve that indicates a relationship between the road-surface friction coefficient and the slip rate, the calculation being performed on the basis of the driving wheel speed, the driven wheel speed, the driving-wheel-speed difference value, the driven-wheel-speed difference value, the driven-wheel-acceleration difference, and the ground load; and
road-surface-condition determining means that determines a road-surface condition on the basis of the amount of change in the road-surface friction coefficient.
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Accused Products
Abstract
A front-wheel speed is calculated as a wheel speed of driving wheels, a rear-wheel speed is calculated as a wheel speed of driven wheels, a rear-wheel acceleration is calculated as a wheel acceleration of the driven wheels, a front-wheel-speed difference value is calculated as a driving-wheel-speed difference value, a rear-wheel-speed difference value is calculated as a driven-wheel-speed difference value, a rear-wheel-acceleration difference value is calculated as a driven-wheel-acceleration difference value, and a front-wheel ground load is calculated as a ground load acting on the driving wheels. Based on these calculated values, a gradient of a tire-characteristic curve indicating an amount of change in road-surface friction coefficient with respect to an amount of change in slip rate is calculated, and the calculated gradient of the tire-characteristic curve is compared with preset threshold values, whereby a road-surface friction coefficient as a road-surface condition can be determined.
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Citations
4 Claims
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1. A road-surface condition estimating device comprising:
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driving-wheel-speed detecting means that detects a speed of a driving wheel; driven-wheel-speed detecting means that detects a speed of a driven wheel; driven-wheel-acceleration detecting means that detects an acceleration of the driven wheel; driving-wheel-speed difference calculating means that calculates a difference between a currently detected driving wheel speed and a previously detected driving wheel speed as a driving-wheel-speed difference driven-wheel-speed difference calculating means that calculates a difference between a currently detected driven wheel speed and a previously detected driven wheel speed as a driven-wheel-speed difference ; acceleration difference calculating means that calculates a difference between a currently detected driven-wheel acceleration and a previously detected driven-wheel acceleration as a driven-wheel-acceleration difference; ground-load calculating means that calculates a ground load acting on the driving wheel; characteristic calculating means that calculates an amount of change in a road-surface friction coefficient with respect to an amount of change in a slip rate in a characteristic curve that indicates a relationship between the road-surface friction coefficient and the slip rate, the calculation being performed on the basis of the driving wheel speed, the driven wheel speed, the driving-wheel-speed difference value, the driven-wheel-speed difference value, the driven-wheel-acceleration difference, and the ground load; and road-surface-condition determining means that determines a road-surface condition on the basis of the amount of change in the road-surface friction coefficient. - View Dependent Claims (2, 3, 4)
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Specification