Road-surface inclined-state detection method and vehicle control method
A road-surface inclined-state detection method includes an acquisition step of acquiring a vehicle state where pitching moment causing front wheels of a vehicle to move upward in a vertical direction relative to rear wheels of the vehicle is applied to the vehicle, and where rear suspensions suspending the rear wheels are stroked in a compressing direction, a count step of starting counting after the vehicle state acquired in the acquisition step meets a predetermined condition, and continuing the counting until the vehicle state fails to meet the predetermined condition, and an inclined-state detection step of detecting an inclined state of a road surface R on which the vehicle travels, according to count values counted in the count step.
1 . A road-surface inclined-state detection method, comprising:
an acquisition step of acquiring a vehicle state where pitching moment causing front wheels of a vehicle to move upward in a vertical direction relative to rear wheels of the vehicle is applied to the vehicle, and where rear suspensions suspending the rear wheels are stroked in a compressing direction;
a count step of starting counting after the vehicle state acquired in the acquisition step meets a predetermined condition, and continuing the counting until the vehicle state fails to meet the predetermined condition; and
an inclined-state detection step of detecting an inclined state of a road surface on which the vehicle travels, according to count values counted in the count step.
2 . The road-surface inclined-state detection method according to claim 1 , wherein
a pitch angular velocity of the vehicle, a pitch angle of the vehicle, and a velocity in the vertical direction of a sprung mass of the vehicle are acquired to acquire the vehicle state in the acquisition step, and
the counting is started in the count step after the pitch angular velocity, the pitch angle, and the velocity in the vertical direction acquired in the acquisition step all exceed predetermined thresholds that are each set corresponding thereto.
3 . The road-surface inclined-state detection method according to claim 2 , wherein each of the predetermined thresholds is set at a value greater than or equal to zero.
4 . The road-surface inclined-state detection method according to claim 3 , wherein the count values are cleared in the count step when any of the pitch angular velocity, the pitch angle, the velocity in the vertical direction acquired in the acquisition step falls to be equal to or lower than the predetermined thresholds.
5 . The road-surface inclined-state detection method according to claim 1 , wherein the count values are saturated in the count step when a predetermined time elapses from start of the counting.
6 . The road-surface inclined-state detection method according to claim 1 , wherein a ramp size of a ramp road surface being the road surface is calculated in the inclined-state detection step according to the count values counted in the count step, and
further comprising: a control step of controlling damping forces of at least either front suspensions or the rear suspensions of the vehicle according to the ramp size.
7 . The road-surface inclined-state detection method according to claim 1 , wherein detection of the inclined state ends in the inclined-state detection step when a stroke of the rear suspensions reaches a largest stretch amount.
8 . The road-surface inclined-state detection method according to claim 2 , wherein the pitch angular velocity, the pitch angle, and the velocity in the vertical direction are acquired based on an electric signal from an inertia measurement unit in the acquisition step.
9 . The road-surface inclined-state detection method according to claim 2 , wherein the pitch angular velocity, the pitch angle, and the velocity in the vertical direction are calculated based on an electric signal from a stroke sensor in the acquisition step.
10 . The road-surface inclined-state detection method according to claim 2 , wherein the pitch angular velocity, the pitch angle, and the velocity in the vertical direction are calculated based on an electric signal from an acceleration sensor in the acquisition step.
11 . The road-surface inclined-state detection method according to claim 1 , wherein the inclined state is detected in the inclined-state detection step when a velocity of the vehicle has a value equal to or more than a predetermined threshold.
12 . A vehicle control method, comprising:
an acquisition step of acquiring a pitch angular velocity of a vehicle, a pitch angle of the vehicle, and a velocity in a vertical direction of a sprung mass of the vehicle;
a count step of starting counting after the pitch angular velocity, the pitch angle, and the velocity in the vertical direction calculated in the acquisition step all exceed predetermined thresholds that are each set corresponding thereto;
a ramp-size calculation step of calculating a ramp size according to count values counted in the count step when a road surface is a ramp road surface; and
a control step of controlling damping forces of at least either front suspensions or rear suspensions of the vehicle according to the ramp size calculated in the ramp-size calculation step.
13 . A vehicle control method, comprising:
a calculation step of calculating a pitch angular velocity of a vehicle, a pitch angle of the vehicle, and a velocity in a vertical direction of a sprung mass of the vehicle, where high-pass filter processing to decrease offset components and drift components in the pitch angular velocity, the pitch angle, and the velocity in the vertical direction is applied;
a count step of starting counting after the pitch angular velocity, the pitch angle, and the velocity in the vertical direction calculated in the calculation step while the high-pass filter processing is applied thereto all exceed predetermined thresholds that are each set corresponding thereto;
an inclined-state detection step of detecting an inclined state of a road surface, according to count values counted in the count step; and
a control step of controlling damping forces of at least either front suspensions or rear suspensions of the vehicle according to the inclined state detected in the inclined-state detection step.