KR101639815B1 - Detecting method of bank-road - Google Patents

Abstract

The present invention relates to a bank load detecting method, and more particularly, to a method and apparatus for detecting a bank load, which includes a first yaw rate estimated through a value measured by a yaw rate sensor, a second yaw rate estimated through a value measured by a lateral acceleration sensor, It is possible to judge whether or not the low friction road surface is running or the bank road is running.

Description

DETECTING METHOD OF BANK-ROAD [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bank load detecting method, and more particularly, to a bank load detecting method capable of comparing a plurality of estimated yaw rate values to determine whether or not a vehicle runs on a bank load.

2. Description of the Related Art Generally, an electronic stability program (hereinafter referred to as ESP) of a vehicle is a system for securing stability of a vehicle as an understeer which is pushed outward beyond a desired traveling course or an undesired turning speed of the vehicle By controlling the braking force and the driving force at oversteering which causes the vehicle stability to be lost due to the sudden decrease of the turning radius, it compensates the undesired vehicle turning moment and maintains the vehicle as a desired turning trajectory.

Such a vehicle stability control system allows a vehicle to travel on a sloping road surface with only a small steering angle when the vehicle runs on a steep road surface in a lateral direction of the vehicle, such as a bank road used for vehicle performance test, The turning speed is small but the vehicle turning speed measured by the vehicle is large. Therefore, the turning state of the vehicle is incorrectly controlled by mistaking the vehicle state as the oversteer state according to the difference of the turning speed, There is a problem that stability is impaired.

In order to prevent this, it is also possible to calculate the lateral inclination angle through the vehicle speed and the lateral acceleration value measured through the lateral acceleration sensor, and to change the oversteer control based on the calculated lateral inclination angle magnitude of the road surface However, there is a problem that the bank road and the road surface can not be distinguished from the low friction road surface.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and system for determining the reliability of an ESP system by determining whether or not a vehicle is traveling on a bank load through a plurality of estimated yaw rate values from respective sensors of a vehicle, And a method for detecting a bank load.

In order to achieve the above-mentioned object, a bank load detecting method according to the present invention is a method for detecting a bank load of a vehicle, comprising the steps of: detecting, at a first yaw rate calculated from a yaw rate sensor of a vehicle, A gradient angle estimating step of estimating a gradient angle by subtracting the yaw rate from the yaw rate and estimating a gradient angle; and a gradient angle comparing step of determining whether the estimated gradient angle estimated in the gradient angle estimating step is equal to or greater than a first reference value, Wherein the absolute value of the first yaw rate is greater than the absolute value of the third yaw rate | Yaw3 | calculated through the steering angle of the vehicle, and the absolute value of the third yaw rate is greater than the absolute value of the third yaw rate Yaw2 |> | Yaw3 |> | Yaw2 |, which is greater than an absolute value (| Yaw2 |) of the second yaw rate, when the third yaw rate is greater than the second yaw rate And the first yaw rate is larger than the third yaw rate, a filtering step of calculating a filtering gradient angle obtained by filtering an estimated gradient angle by multiplying a first gain by the estimated gradient angle when aw1 |> | Yaw3 |> | Yaw2 | And if the filtering gradient angle is larger than the second reference value, it is determined that the running road on which the vehicle travels is a bank load having a gradient angle.

In the filtering step, if the yaw rate comparison step does not satisfy | Yaw1 |> | Yaw3 |> | Yaw2 |, the filtered gradient angle obtained by multiplying the estimated gradient angle by the second gain, which is a value smaller than the first gain, Can be calculated.

In the filtering step, if the estimated gradient angle is less than the first reference value in the gradient angle comparing step, a filtering gradient angle obtained by filtering the third gradient, which is smaller than the second gain, by the estimated gradient angle may be calculated .

If the filtering gradient angle is less than the second reference value in the gradient angle determination step, it can be determined that the vehicle is not traveling on the bank road.

The bank load detecting method according to the present invention can improve the reliability of the ESP system by determining whether the vehicle is traveling through the bank load through a plurality of estimated yaw rate values from respective sensors of the vehicle.

1 is a flowchart illustrating a bank load detection method according to an embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily carry out the present invention.

Referring to FIG. 1, a method of detecting a bank load according to an embodiment of the present invention is illustrated.

First, the bank load detection method calculates a first yaw rate (Yaw1) based on a yaw rate value measured at a yaw rate sensor of a vehicle, calculates a first yaw rate (Yaw1) based on a lateral acceleration value measured by a vehicle lateral acceleration sensor 2 Yaw rate (Yaw2) is calculated. The estimated gradient angle Bc is calculated S1 by subtracting the second yaw rate Yaw2 from the first yaw rate Yaw1 to estimate whether the road surface on which the vehicle travels is a bank road. Here, a bank road is a curved road on which the road on which the vehicle is traveling has biaxial sideways, and means a road that must be rotated in the direction in which the draft angle exists.

The calculation of the estimated gradient angle (Bc) is performed by a controller of an electronic stability program (ESP) for securing the driving safety of the vehicle.

First, the first yaw rate is calculated from the equation (1) as the yaw rate value generated in the vehicle.

Here, Yaw1 is the first yaw rate, ψ is the yaw rate measured by the yaw rate sensor, and Yos is the yaw rate offset value.

The second yaw rate (Yaw2) is calculated from the equation (2) by the yaw rate estimated through the lateral acceleration generated in the vehicle.

Here, Yaw2 is the second yaw rate, ay is the lateral acceleration value of the vehicle measured by the lateral acceleration sensor, and Vref is the running speed of the vehicle.

And a gradient angle comparator for determining whether the estimated gradient angle Bc calculated by subtracting the second yaw rate Yaw2 from the first yaw rate Yaw1 is greater than a first reference value Bt1 stored in the ESP controller Step S2 is executed. The first reference value Bt1 may preferably be 0.2 (g), but the present invention is not limited thereto.

A yaw rate comparing step S3 for determining a gain value to confirm that the traveling path on which the vehicle travels is an inclined road surface having a gradient angle if the estimated gradient angle Bc is larger than the first reference value Bt1 ). First, the ESP controller calculates the third yaw rate (Yaw3) through the steering angle of the vehicle. This third yaw rate (Yaw3) is calculated by the yaw rate equation (3) estimated through the steering angle of the vehicle.

Where I _L is the steering ratio, I is the inter-axis distance, which is the distance between the front and rear wheels of the vehicle, and V ch is the characteristic speed of the vehicle set in the ESP controller, to be. Therefore, the third yaw rate (Yaw3) is proportional to the steering angle of the vehicle in a vehicle traveling at the same speed.

And the absolute value | Yaw3 | of the third yaw rate Yaw3 is greater than the absolute value | Yaw3 | of the third yaw rate Yaw3, Is larger than the absolute value (| Yaw2 |) of the second yaw rate (Yaw2). That is, in the yaw rate comparison step S3, it is determined whether or not the vehicle satisfies | Yaw1 |> | Yaw3 |> | Yaw2 | to determine whether or not the vehicle is traveling on the bank road.

Then, if the vehicle is traveling on the bank road, the first yaw rate (Yaw1), the second yaw rate (Yaw2) and the third yaw rate (Yaw3) are generated in the vehicle.

And on the bank road, the vehicle is able to rotate the same vehicle at a smaller steering angle than when driving on a flat road. Therefore, if the vehicle is traveling on the bank road, the first yaw rate (Yaw1) calculated through the yaw rate sensor value becomes larger than the third yaw rate (Yaw3) estimated through the steering angle of the vehicle. In this case, the reason why the absolute value is added to the yaw rate is to compare only the yaw rate.

If the vehicle is traveling on the bank road, the gravity applied to the vehicle is canceled by the centrifugal force due to the rotation, and the second yaw rate (Yaw2) estimated through the lateral acceleration sensor value is close to zero. When the vehicle travels on a low friction surface, the second yaw rate value can not be close to 0 because the centrifugal force can not be canceled by gravity. That is, the first yaw rate Yaw1 and the third yaw rate Yaw3 become larger than the second yaw rate Yaw2 only when the vehicle is traveling on the bank road.

Therefore, if | Yaw1 |> | Yaw3 |> | Yaw2 | is satisfied, it is determined that the vehicle is traveling on the bank road.

However, even if the vehicle does not satisfy the condition of | Yaw1 |> | Yaw3 |> | Yaw2 |, the vehicle may be traveling on the bank road, so that even if | Yaw1 |> | Yaw3 |> | Yaw2 | To confirm once, the estimated gradient angle is filtered using the gain, and the bank load verification is performed through the filtering gradient angle.

In order to confirm whether or not the bank road is running through the filtering gradient angle, the first gain and the second gain are filtered to filter the estimated gradient angle Bc according to whether the gradient angle comparison step S2 and the yaw rate comparison step S3 are satisfied. 2 gain and the third gain is set to gain (S4). Then, the filtering gradient angle is calculated by multiplying each of the gains calculated for the estimated gradient angle Bc (S5). Then, it is determined whether or not the vehicle is traveling on the bank road, based on whether or not the filtering gradient angle Bf is larger than the second reference value Bt2 (S6).

If the estimated gradient angle Bc is smaller than the first reference value Bt1 in the gradient angle comparing step S2, it is determined that the vehicle is not likely to travel on the bank road. If the first gain and the second gain (S43), and the filtered gradient angle Bt is calculated by multiplying the estimated gradient angle Bc by the third gain.

If the estimated gradient angle Bc is larger than the first reference value Bt1 in the gradient angle comparing step S2 but the yaw rate comparing step S3 does not satisfy | Yaw1 |> | Yaw3 |> | Yaw2 | A second gain smaller than the first gain and larger than the third gain is set to gain (S42), and the filtering gradient angle Bt is calculated by multiplying the estimated gradient angle Bc by the second gain.

If the estimated gradient angle Bc is larger than the first reference value Bt1 in the gradient angle comparing step S2 but the yaw rate comparing step S3 satisfies | Yaw1 |> | Yaw3 |> | Yaw2 | The first gain larger than the second gain and the third gain is set to gain (S41), and the filtering gradient angle Bt is calculated by multiplying the estimated gradient angle Bc by the first gain.

That is, the gain value for filtering the estimated gradient angle Bc is determined according to whether or not the gradient angle comparing step S2 and the yaw rate comparing step S3 are satisfied.

For example, the first gain may be set to 0.95, the second gain to 0.4, and the third gain to 0.1. Since the filtering gradient angle Bt is different according to the set gain value, the second reference value Bt2 for determining whether or not the vehicle is traveling on the bank road can be set differently depending on the set gain value. When each gain value is set as described above, the second reference value Bt2 can be set to 0.082 (g).

The filtering gradient angle Bf is calculated by multiplying the estimated gradient angle Bc by the gain and compared with the second reference value Bt2 stored in the ESP controller so that the filtering gradient angle Bf is smaller than the second reference value Bt2 , It is determined that the vehicle is traveling on the bank road (S7).

That is, if the filtering gradient angle Bf filtered by the third gain is larger than the second reference value Bt2 even if both of the gradient angle comparing step S2 and the yaw rate comparing step S3 are not satisfied, It is judged that the vehicle runs on the bank road. However, since the filtered gradient angle Gf is calculated by multiplying the estimated gradient angle Bc by the third gain smaller than the first gain or the second gain, the probability that the vehicle is judged to run on the bank load is calculated by the gradient angle comparison step (S2) and the yaw rate comparing step (S3) are satisfied.

If the filtering gradient angle Bf is equal to or less than the second reference value Bt2, it is determined that the vehicle does not travel on the bank road but runs on a flat or low friction road surface (S8).

Thus, in order to detect whether or not the vehicle is traveling on the bank road, the present invention is characterized in that the first yaw rate (Yaw1) estimated through the measured value at the yaw rate sensor and the second yaw rate The yaw rate Yaw2 is compared with the third yaw rate Yaw3 estimated through the steering angle to determine whether or not the vehicle is traveling on the bank road.

As described above, the present invention is not limited to the above-described embodiments, but may be applied to a method of detecting a bank load according to the present invention, It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

Yaw1; First yaw rate Yaw2; Second yaw rate
Yaw3; Third yaw rate Bc; Estimated gradient angle
Bf; Filtering gradient angle Bt1; The first reference value
Bt2; The second reference value

Claims (4)

A gradient angle estimating step of estimating a gradient angle by subtracting a second yaw rate calculated from a value measured by a lateral acceleration sensor of the vehicle at a first yaw rate calculated through a value measured by a yaw rate sensor of the vehicle;
A gradient angle comparing step of determining whether the estimated gradient angle estimated in the gradient angle estimating step is equal to or greater than a first reference value;
Wherein the absolute value of the first yaw rate is greater than the absolute value of the yaw rate of the third yaw rate calculated based on the steering angle of the vehicle, Comparing the absolute value of the third yaw rate with the absolute value of the second yaw rate | Yaw1 |> | Yaw3 |> | Yaw2 |
If the third yaw rate is larger than the second yaw rate and the first yaw rate is larger than the third yaw rate and satisfies | Yaw1 |> | Yaw3 |> | Yaw2 |, the first gain may be set to the estimated gradient angle A filtering step of calculating a filtering gradient angle obtained by filtering an estimated gradient angle by multiplying the estimated gradient angle by a filtering step;
If the filtering gradient angle is larger than the second reference value, determining whether the filtering gradient angle is equal to or greater than the second reference value, and determining whether the filtering gradient angle is greater than the second reference value, And determining a traveling direction of the vehicle. The method according to claim 1,
In the filtering step
If the yaw rate comparison step does not satisfy | Yaw1 |> | Yaw3 |> | Yaw2 |, the filtering gradient angle obtained by filtering the second gradient, which is smaller than the first gain, by the estimated gradient angle is calculated And detecting a bank load. The method of claim 2,
In the filtering step
Wherein when the estimated gradient angle is less than the first reference value in the gradient angle comparison step, the filtering gradient angle obtained by filtering the third gradient, which is smaller than the second gain, by the estimated gradient angle is calculated. Detection method. The method according to any one of claims 1 to 3,
In the bank load running determination step
And judges that the vehicle does not travel on the bank road if the filtering gradient angle is less than the second reference value.

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