Tire burst prediction device
A tire burst predicting device which can predict occurrence of bursting of a tire and gives an alarm properly is provided. A break point frequency is estimated on the basis of time series data of wheel speed detected at a wheel speed sensor from frequency response of a first order model to which a transmission characteristic from a road surface disturbance to a wheel speed is approximated. A braking force gradient corresponding to the estimated break point frequency is estimated, on the basis of a map, which is prestored, representing a relationship between break point frequencies and braking force gradients. Extra high frequency components are eliminated from the estimated braking force gradient by a low pass filter to reduce estimation dispersion. Differentiators detect changing speed of the braking force gradient. An alarm is given when there is a possibility of bursting of tire when the detected changing speed reaches or exceeds a predetermined threshold value.
1. A tire burst predicting device comprising:
wheel speed detecting means which detects a speed of a wheel;
ground contact state estimating means which estimates a physical quantity representing a ground contact state between the wheel and a road surface on the basis of the detected wheel speed;
rate of change detecting means which detects a rate of change of the estimated physical quantity representing the ground contact state between the wheel and the road surface; and
predicting means which predicts occurrence of bursting of the wheel by judging whether or not the detected rate of change is a value outside of a predetermined range.
2. The tire burst predicting device of claim 1 further comprising alarming means which gives an alarm relating to bursting of the wheel, wherein the predicting means judges whether or not the detected rate of change is a value outside of the predetermined range, and the alarming means gives the alarm in a case in which the detected rate of change is a value outside of the predetermined range.
3. The tire burst predicting device of claim 1 further comprising driving force suppressing means which suppresses a driving force of the wheel, wherein the predicting means judges whether or not the detected rate of change is a value outside of the predetermined range, and the driving force suppressing means suppresses the driving force of the wheel in a case in which the detected rate of change is a value outside of the predetermined range.
4. The tire burst predicting device of claim 2 further comprising driving force suppressing means which suppresses a driving force of the wheel, wherein the predicting means judges whether or not the detected rate of change is a value outside of the predetermined range, and the driving force suppressing means suppresses the driving force of the wheel in a case in which the detected rate of change is a value outside of the predetermined range.
5. The tire burst predicting device of claim 1 , wherein the ground contact state estimating means comprises smoothing means which smoothes the physical quantity representing the ground contact state, and a differentiator which differentiates the smoothed physical quantity representing the ground contact state.
6 .The tire burst predicting device of claim 2 , wherein the ground contact state estimating means comprises smoothing means which smoothes the physical quantity representing the ground contact state, and a differentiator which differentiates the smoothed physical quantity representing the ground contact state.
7. The tire burst predicting device of claim 3 , wherein the ground contact state estimating means comprises smoothing means which smoothes the physical quantity representing the ground contact state, and a differentiator which differentiates the smoothed physical quantity representing the ground contact state.