Method for measuring vertical acceleration and velocity of semi-active suspension system
View Patent ↗The present invention relates to a method for measuring a vertical acceleration and a velocity of a semi-active suspension system. Particularly, the present invention provides a method for obtaining a vertical acceleration from vertical accelerations measured from three vertical acceleration sensors of a semi-active suspension system of a vehicle, comprising the steps of: receiving first to third vertical accelerations measured from first to third vertical acceleration sensors; and obtaining a fourth vertical acceleration (Ad) by multiplying the first to third vertical accelerations by correction constants and subsequently summing up them. Therefore, according to the present invention, a fourth vertical acceleration can be obtained by multiplying the three vertical accelerations measured from the three acceleration sensors by the constants for correcting them to accelerations at actually desired damper positions and subsequently summing up them, thereby enabling accurate measurement and correction of the vertical accelerations.
1. A method for controlling a semi-active suspension system, wherein the semi-active suspension system comprises the first to third vertical acceleration sensors which are installed adjacent to three of the four dampers of the vehicle body, the method comprises the steps of:
receiving first to third vertical accelerations measured from first to third vertical acceleration sensors;
obtaining a vertical aeceleration value (Ad) at the position of the fourth damper using said first to third vertical accelerations and the correction constants α, β, γ at the position of the fourth damper where any vertical acceleration sensor is not installed adjacently, wherein the correction constants at the position of the fourth damper is obtained from x and y position value of the fourth damper and X and Y position values of the first to the third acceleration sensors; and
controlling damping forces of the first to fourth dampers according to vertical acceleration values including said vertical acceleration value (Ad) at the position of the fourth damper wherein the vertical Acceleration value (Ad) is obtained from the following equation:
Ad=α×Aa 1+β× Aa 2+γ× Aa 3
and, the correction constants α, β and γ are obtained from the following equation:
α
(
x
,
y
)
=
(
Y
2
-
Y
3
)
x
+
(
X
3
-
X
2
)
y
+
X
2
Y
3
-
X
3
Y
2
(
X
1
-
X
2
)
(
Y
1
-
Y
3
)
-
(
X
1
-
X
3
)
(
Y
1
-
Y
2
)
β
(
x
,
y
)
=
(
Y
3
-
Y
1
)
x
+
(
X
1
-
X
3
)
y
+
X
3
Y
1
-
X
1
Y
3
(
X
1
-
X
2
)
(
Y
1
-
Y
3
)
-
(
X
1
-
X
3
)
(
Y
1
-
Y
2
)
γ
(
x
,
y
)
=
(
Y
1
-
Y
2
)
x
+
(
X
2
-
X
1
)
y
+
X
1
Y
2
-
X
2
Y
1
(
X
1
-
X
2
)
(
Y
1
-
Y
3
)
-
(
X
1
-
X
3
)
(
Y
1
-
Y
2
)
,
where X 1 , X 2 and X 3 are X position coordinate values of the first to third vertical acceleration sensors, Y 1 , Y 2 and Y 3 are Y position coordinate values of the first to third vertical acceleration sensors, and x and y are X and Y position coordinate values of the fourth damper where any vertical acceleration sensor is not installed adjacently.
2. The method as claimed in claim 1 , before the step of controlling damping forces of the first to fourth dampers, further comprising the step of correcting the first to third vertical accelerations measured from the first to third vertical acceleration sensors to three vertical acceleration values at the positions of corresponding the first to third dampers using the following equations:
Aα n [1]=α[1]× Aα [1]+β[1]× Aα[ 2]+γ[1]× Aα [3]
Aα n [2]=α[2]× Aα [1]+β[2]× Aα[ 2]+γ[2]× Aα [3]
Aα n [3]=α[3]× Aα [1]+β[3]× Aα[ 2]+γ[3]× Aα [3]
where Aa n [1], Aa n [2] and Aa n [3] are vertical acceleration values corrected to the vertical accelerations at the positions of first to third dampers, α[1], β[1] and γ[1] are correction constants at the position of the first damper, α[2], β[2] and γ[2] are correction constants at the position of the second damper, and α[3], β[3] and γ[3] are correction constants at the position of the third damper.
3. A method for controlling a semi-active suspension system, wherein the semi-active suspension system comprises the first to third velocity sensors which are installed adjacent to three of the four dampers of the vehicle body, the method comprises the steps of:
receiving first to third velocities measured from first to velocity sensors;
obtaining a velocity value (Vd) at the position of the fourth damper using said first to third velocities and the correction constants α, β and γ at the position of the fourth damper where any velocity sensor is not installed adjacently, wherein the correction constants at the position of the fourth damper is obtained from x and y position value of the fourth damper and X and Y position values of the first to the third velocity sensors; and
controlling damping forces of the first to fourth dampers according to velocity values including said velocity value (Vd) at the position of the fourth damper wherein the velocity value (Vd) is obtained from the following equation:
Vd=α×Vα 1+β× Vα 2+γ× Vα 3
and, the correction constants α, β and γ are obtained from the following equation:
α
(
x
,
y
)
=
(
Y
2
-
Y
3
)
x
+
(
X
3
-
X
2
)
y
+
X
2
Y
3
-
X
3
Y
2
(
X
1
-
X
2
)
(
Y
1
-
Y
3
)
-
(
X
1
-
X
3
)
(
Y
1
-
Y
2
)
β
(
x
,
y
)
=
(
Y
3
-
Y
1
)
x
+
(
X
1
-
X
3
)
y
+
X
3
Y
1
-
X
1
Y
3
(
X
1
-
X
2
)
(
Y
1
-
Y
3
)
-
(
X
1
-
X
3
)
(
Y
1
-
Y
2
)
γ
(
x
,
y
)
=
(
Y
1
-
Y
2
)
x
+
(
X
2
-
X
1
)
y
+
X
1
Y
2
-
X
2
Y
1
(
X
1
-
X
2
)
(
Y
1
-
Y
3
)
-
(
X
1
-
X
3
)
(
Y
1
-
Y
2
)
,
where X 1 , X 2 and X 3 are X position coordinate values of the first to third velocity sensors, Y 1 , Y 2 and Y 3 are Y position coordinate values of the first to third velocity sensors, and x and y are X and Y position coordinate values of the fourth damper where any velocity sensor is not installed adjacently.
4. The method as claimed in claim 3 , before the step of controlling damping forces of the first to fourth dampers, further comprising the step of correcting the first to third velocities measured from the first to third velocity sensors to three velocity values at the positions of corresponding the first to third dampers using the following equations:
Vα n [1]=α[1]× Vα [1]+β[1]× Vα [2]+γ[1]× Vα [3]
Vα n [2]=α[2]× Vα [1]+β[2]× Vα [2]+γ[2]× Vα [3]
Vα n [3]=α[3]× Vα [1]+β[3]× Vα [2]+γ[3]× Vα [3]
where Va n [1], Va n [2] and Va n [3] are velocity values corrected to the velocities at the positions of first to third dampers, α[1], β[1] and γ[1] are correction constants at the position of the first damper, α[2], β[2] and γ[2] are correction constants at the position of the second damper, and α[3], β[3] and γ[3] are correction constants at the position of the third damper.