| 摘要 |
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. |
