KR101795251B1 - Method for controlling braking force by considering driver's propensity to brake - Google Patents

Abstract

The present invention relates to a method for controlling a braking force in consideration of a drivers propensity to brake and, more specifically, provides a method for controlling a braking force in consideration of a drivers propensity to brake, which corrects and controls a braking force in accordance with a request of a driver in consideration of a drivers propensity to brake. Therefore, a braking feel is appropriately maintained to prevent the driver from feeling that a brake pedal works improperly, and at the same time, the braking force is reduced to improve fuel efficiency.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a braking force control method,

The present invention relates to a braking force control method considering a braking tendency of a driver, and more particularly, to a braking force control method for controlling a braking force of a driver in consideration of a driver's braking tendency, The present invention relates to a braking force control method for controlling a braking force of a vehicle.

Generally, the driver adjusts the vehicle braking amount to match the characteristics of the braking device mounted on the vehicle. That is, the driver adjusts the vehicle braking amount in accordance with the characteristics of the braking device.

To this end, the driver grasps the characteristics of the braking device through repetitive vehicle braking and adjusts the braking amount by adjusting the pedal force and the like according to the characteristics of the braking device.

However, even if the same braking device is mounted on the same vehicle, it may feel that the depression of the brake pedal is sensitive depending on the driving propensity of the driver and the physical conditions, and that the deceleration does not occur as much as the driver depresses the brake pedal. There is a problem that the sense of familiarity is deteriorated.

The present invention relates to a driver control system that corrects and controls a braking force according to a driver's request in consideration of a braking tendency of a driver, thereby appropriately maintaining the braking force so that the driver does not feel that the brake pedal is being pushed, And a braking force control method considering the braking tendency.

Accordingly, it is a first object of the present invention to provide a braking force control apparatus for a vehicle, comprising: a first step of determining whether a braking force learning for correcting a target braking force, which is generated in accordance with a stroke of a brake pedal, A second step of selecting a braking force correction criterion for determining a braking force correction learning amount of the target braking force among the driver braking demand amount and the fuel consumption ratio when the braking force learning is possible; And a third step of performing braking force learning by correcting the target braking force using the braking force correction learning amount determined in accordance with the selected braking force correction standard.

Specifically, in the first step, it is determined whether the vehicle is suddenly stopped based on the deceleration of the vehicle, whether the safety distance to the front vehicle is secured according to the vehicle speed, the stroke variation and the variation frequency of the brake pedal, and the vehicle is located apart from the intersection by a predetermined distance Whether or not the front signal light signal is in a traveling state, whether there is a traffic sign associated with the vehicle speed reduction state on the road under driving, whether the yaw rate and lateral acceleration of the vehicle are less than the reference yaw rate and the reference lateral acceleration, respectively, It is determined that the braking force learning is possible if the conditions for whether the steering angle is less than the reference steering angle are satisfied.

The second step may include: calculating an on-demand stop score (Davg) indicating a degree of satisfaction of a driver braking demand; Calculating an economy stop score (Escore) indicating a degree of satisfaction of fuel economy in a braking situation; Calculating a total stop score (Tscore) as a sum of the on-demand stop score (Davg) and the economy stop score (Escore) based on the economy stop weight (?); And determining a braking force correction standard on the basis of a driver braking demand amount and a fuel consumption ratio according to a magnitude comparison result of an on-demand stop score (Davg) and an economy stop score (Escore) when the total stop score is less than a set reference stop score.

The step of calculating the on-demand stop score (Davg) includes the steps of: quantifying the driver braking demand satisfaction rate according to the stroke variation amount of the brake pedal whenever stroke variation of the brake pedal occurs; And determining an on-demand stop score (Davg) as a value obtained by averaging the numerical satisfaction of the driver braking demand,

The step of determining the economy stop score (Escore) includes: calculating an optimum fuel-economy required deceleration; Calculating a difference value (DECdiff) between the vehicle actual deceleration and the fuel economy optimum required deceleration; Calculating an economy stop score (Escore) as a value obtained by cumulatively adding the difference value (DECdiff) generated during vehicle braking,

In the step of determining the braking force correction reference, the on-demand stop score (Davg) is compared with the economy stop score (Escore). If the on-demand stop score is equal to or higher than the economy stop score, If the demanded stop score is below the economy stop score, the fuel economy is selected as the braking force correction standard.

The step of calculating the fuel economy optimum required deceleration may further comprise the steps of: (a) setting a basic recommended deceleration; (b) calculating a predicted distance until a vehicle stops while the vehicle is running; (c) calculating a required deceleration until stopping based on the estimated distance calculated in the step (b); (d) determining a greater value of the deceleration calculated in the step (c) and the basic recommended deceleration as the fuel economy optimum required deceleration.

According to the present invention, the braking force for improving the fuel economy can be realized within a range that does not hinder the driver's sense of driver's control.

FIG. 1 is a flowchart showing a case where braking force learning is possible for braking force control according to the present invention, and actuator driving is performed for generating a braking force corrected according to the braking force learning.
2 is a schematic flow chart showing a process of learning braking force when a driver is requested to braking for braking force control according to the present invention.
3 is a flowchart illustrating a process for determining whether braking force learning is possible for braking force control according to the present invention.
4 is a flowchart illustrating a method for determining a braking force correction reference in accordance with the present invention.
Figure 5 is a flow diagram illustrating a method for computing an on-demand stop score (Davg)
FIG. 6 is a diagram for explaining a method of calculating a stroke change amount of a brake pedal according to the present invention; FIG.
7 is a diagram for explaining a calculation method of the degree of satisfaction with respect to the driver's braking demand from the under stroke change amount and the over-stroke change amount of the brake pedal according to the present invention
8 is a flowchart illustrating a method for calculating an economy stop score (Escore) according to the present invention.
9 is a diagram illustrating a method of calculating an economy stop score (Escore) by digitizing the difference value between the fuel economy optimum required deceleration and the actual vehicle deceleration according to the present invention
10 is a schematic diagram showing an interlocking relationship between an economy stop score (Escore) according to the present invention and a difference value (DECdiff) between an optimum required deceleration of fuel consumption and a vehicle actual deceleration
11 is a diagram showing a braking force correction reference determination method according to the present invention;
12 is a graph illustrating a target deceleration rate that varies according to a stroke of a brake pedal after execution of braking force learning according to the present invention

Hereinafter, the present invention will be described with reference to the accompanying drawings.

The present invention relates to a hydraulic-pressure-type braking device in which a braking force is electronically controlled as a driver depresses a brake pedal, wherein the braking force is learned and corrected in accordance with the driver's braking tendency, and the braking force is actively adjusted The braking force can be corrected and controlled based on both the braking force level for improving the fuel economy and the braking force required for the driver so that the braking force is reduced relative to the driver braking force and the driver feels that the brake pedal is pushed Ensure that your feelings are properly maintained. In addition, when it is determined that the driver feels a trembling feeling in braking by reducing the braking force to improve the fuel efficiency, the braking force control is performed in a direction to increase the braking force.

Therefore, in the present invention, when the driver feels that the brake pedal is pushed as much as the driver does not by the reduction of the braking force by reducing the braking force to improve the fuel efficiency of the vehicle, the braking force learning (i.e., the target braking force correction) By slightly reducing the braking force reduction amount in order to improve the fuel efficiency relative to the driver braking required amount by accumulating the braking force little by little in the direction of increasing the braking force of the vehicle with respect to the same pedal depression amount (brake pedal stroke) So that the braking force can be improved to such an extent that the brake pedal does not feel depressed.

As a result, in accordance with the present invention, as the braking force learning amount (i.e., the braking force correction amount) of the vehicle is increased, the braking force desired by the driver, the minimum braking force for improving the fuel economy, and the braking force level of the braking device adapted to the driver The braking force of the braking device which is generated according to the volume of the braking device) is matched with the braking force of the braking device.

FIG. 1 shows a case where braking force learning is possible based on detection results of driver braking request information, vehicle state information, vehicle external environment information, traffic information, and the like, and shows that the actuator is driven for generating braking force FIG. 2 is a flowchart showing a process of learning braking force when a driver braking is requested, and FIG. 3 is a flowchart illustrating a process of determining whether braking force learning is possible.

First, in order to determine whether braking force learning is possible in a situation where a driver braking demand occurs, driver braking request information, vehicle state information, vehicle environment information, and network traffic information detected in real time are used as shown in FIG. 1 .

The driver braking request is grasped based on information such as the stroke of the brake pedal, the pressure of the brake master cylinder, the steering angle of the steering wheel, and the vehicle state is grasped based on information such as vehicle speed, deceleration, yaw rate, lateral acceleration, The external environment of the vehicle is determined based on information such as a distance between the vehicle and a preceding vehicle, a distance between the vehicle and a preceding obstacle, a position of the vehicle (GPS position), a gradient of the road and the network traffic information includes traffic sign position and contents, , An intersection position, a construction position, and the like.

For example, it is possible to determine whether or not the vehicle braking is occurring based on the driver braking request information.

It detects the above information in real time and determines whether or not it is possible to learn the braking force of the vehicle based on the sensed information.

As shown in FIG. 2, when the driver brakes the vehicle by depressing the brake pedal, it is determined whether or not the braking force (target braking force according to the stroke of the brake pedal) can be learned based on the above information, (That is, the braking force correction value) for determining the braking force correction reference value for determining the braking force correction reference value.

Then, the braking force learning is performed by correcting the target braking force using the braking force correction learning amount calculated according to the determined braking force correction standard, and the learned braking force is reflected at the next braking.

Therefore, the final braking force (target braking force + braking force correction learning amount) corrected through braking force learning becomes the target braking force at the next braking.

In other words, the final braking force (target braking force + braking force correction learned amount) corrected by adding the braking force correction learning amount (braking force correction value) to the target braking force matched to the predetermined pedal stroke becomes the target braking force at the next braking.

At this time, the final braking force is realized by driving the actuator for generating the braking force of the braking device.

The in-vehicle control unit for performing the braking force learning together with the braking force learning includes a driver braking demand sensing unit for sensing the driver braking demand, a vehicle state sensing unit for sensing the vehicle state, And a network traffic information sensing unit for sensing the network traffic information.

In addition, in order to determine whether or not the braking force learning is possible when the vehicle braking is requested, in a braking situation in which the conditions such as the sudden braking state, the traffic signal, and the turning state are unclear for determining whether braking force learning is possible, Exclude learning.

Therefore, as shown in Fig. 3, a condition in which the distance from the forward object is sufficiently secured in accordance with conditions other than the sudden braking situation, a condition in which the stroke variation amount of the brake pedal and the variation frequency (movement frequency) A condition in which the vehicle is not in proximity to the vehicle or the traffic light signal in front of the vehicle is a green (signal capable of running) on the basis of the traveling direction, a condition in which there is no traffic sign associated with the vehicle speed reduction situation, If all of these small conditions are satisfied, it is determined whether or not the braking force learning is possible at the time of vehicle braking and the execution of the braking force learning is determined.

Here, whether or not the sudden braking state is determined is determined as the vehicle deceleration magnitude value, and it is determined that the vehicle is not in a sudden braking state if the deceleration of the vehicle is equal to or less than a first reference value (reference deceleration).

The distance to the forward object according to the vehicle speed is determined by comparing with a second reference value (reference interval) that is variably determined according to the vehicle speed, and when the distance from the forward object is equal to or greater than the second reference value, Is secured.

At this time, the second reference value may be acquired from a map constructed in advance to determine a second reference value according to the vehicle speed.

Next, if the stroke variation amount of the brake pedal and the number of times of positional variation of the brake pedal are respectively equal to or less than the third reference value (reference variation amount) and the fourth reference value (reference variation number), the driver's sudden or frequent brake pedal operation .

If the vehicle is located at a position separated from the intersection by a predetermined reference value (reference distance) or more, it is determined that the vehicle is not approaching the intersection. At this time, the vehicle position and the distance to the intersection are determined in real time can do.

It is possible to determine the presence or absence of a traffic sign that causes a vehicle speed reduction situation based on traffic information provided by navigation or electronic traffic sign information and it is possible to determine whether or not there is an electronic traffic sign , It is judged that there is no traffic sign around the vehicle (that is, on the running road) that causes the vehicle speed reduction situation.

The yaw rate, the lateral acceleration, and the steering angle information of the vehicle can be acquired from a yaw rate sensor, a lateral acceleration sensor, and a steering angle sensor installed in the vehicle. The acquired yaw rate and lateral acceleration information are respectively set to a sixth reference value Rate) and the seventh reference value (reference lateral acceleration), or if the obtained steering angle information is smaller than the set eighth reference value (reference steering angle), it is judged that the conditions capable of braking force learning are satisfied.

The braking force learning is performed by correcting the target braking force that matches the stroke of the brake pedal generated in accordance with the driver's abilities. The learned braking force is reflected at the next braking.

Here, the braking force correction is performed from two viewpoints. The first is the viewpoint of whether the braking force is generated as much as the driver wants. An on demand stop score (or driver braking demand satisfaction score) is introduced as an index indicating how much the driver braking demand is satisfied from the viewpoint of the driver braking demand. The second is vehicle fuel efficiency. Since the unnecessary sudden braking deteriorates the fuel efficiency of the vehicle, an index indicating whether the braking force is generated at a level at which the braking force can be improved in terms of fuel economy (that is, an index indicating the degree of satisfaction of the fuel economy in the braking situation) is referred to as an economy stop score Satisfaction score).

The braking force correction learning amount is finally determined by setting a weight (?) As a constant value to what degree the weight is to be given to the fuel consumption point from the two viewpoints, and the on-demand stop score (Davg) and the economy stop score Escore), it is determined which point of view the braking force correction is to be performed on, and then braking force learning is performed according to the braking force correction.

Accordingly, as shown in FIG. 4, the process of selecting and determining the braking force correction reference includes: calculating an on-demand stop score (Davg); Calculating an economy stop score (Escore); Calculating a total stop score (Tscore) as a sum of the on-demand stop score (Davg) and the economy stop score (Escore) based on the economy stop weight (?) Determined for the economy stop score (Escore); If the total stop score is less than the preset reference stop score (T _threshold ), the braking force correction criterion during driver braking demand and fuel consumption is selected and determined according to the magnitude comparison result of the on-demand stop score Davg and the economy stop score (Escore) The braking force correction learning amount is determined and calculated based on the braking force correction reference thus determined.

5, in the step of calculating the on-demand stop score Davg, the pedal stroke pattern generated by the brake pedal depression of the driver is determined, and the stroke change amount according to the pedal stroke pattern is calculated / grasped step; Numerically expressing the degree of satisfaction of the driver's braking demand amount according to the stroke change amount of the brake pedal whenever stroke variation (position variation) of the brake pedal occurs; And determining / calculating an on-demand stop score (Davg) as an average value of the calculated braking demand satisfaction degree.

6 (a) shows the vehicle deceleration and brake pedal stroke as the brake pedal is additionally depressed by the driver since the desired deceleration (required deceleration) does not occur after the driver performs the braking by depressing the brake pedal. Fig. 6 (B) is a situation opposite to (a) in which the vehicle decelerates after the driver depresses the brake pedal and then decelerates to a desired deceleration (over-brakeing) And brake pedal strokes.

Referring to FIG. 6A, if the desired deceleration (required deceleration) does not occur after the lapse of the predetermined time ΔT _A after the driver depresses the brake pedal for braking the vehicle, the driver releases the brake pedal I will step further. The under braking stroke (? S _{underbraking1} ) of the brake pedal which is additionally depressed after a predetermined time (? T _B ) after the brake pedal is further depressed can be calculated.

In other words, since the detected brake pedal stroke and the required deceleration rate are not satisfied after the driver has depressed the brake pedal first time and the predetermined time (DELTA _{T A} ) has elapsed, the predetermined time DELTA T _B The under brake stroke (? S _{underbraking1} ) of the brake pedal which is additionally (secondarily) depressed, that is, the under-stroke change amount of the brake pedal (δS _{underbraking1} ).

At this time, the brake pedal stroke can be detected through the brake pedal position sensor of the vehicle.

Referring to FIG. 6B, when a vehicle deceleration that is greater than a desired deceleration (required deceleration) occurs after a lapse of a predetermined time ΔT _A after the driver steps on the brake pedal, The pedal pressure is reduced by reducing the pedal pressure. Can reduce the volume of the step on the brake pedal, and to calculate the certain period of time (δT _B) over-braking stroke (δS _{overbraking1)} of the brake pedal according to the pedal tread volume was reduced after the last.

In other words, the driver is also the brake pedal 1 is detected after the lapse of drive behind a certain period of time (δT _A) step on the brake pedal stroke, the required deceleration is generated excessively reducing step on the volume of the second drive (added to) the brake pedal The over brake stroke? S _overbraking1 of the brake pedal, which is changed by adjusting the pedal depression force in addition to (secondarily) calculating the difference between the brake pedal strokes detected after a predetermined time? T _B , The overstroke change amount? S _{overbraking 1} of the brake pedal that occurs due to the failure of the brake pedal can not be obtained.

Accordingly, when the driver depresses the brake pedal at the time of braking the vehicle, it is determined that the stroke pattern of the brake pedal is an under-stroke pattern (or an under braking pattern). When the driver reduces the amount of stepping on the brake pedal, It is judged that the pattern is an overstroke pattern (or an overbraking pattern).

The degree of satisfaction with the driver's braking demand can be quantified (D _underbraking , D _overbraking ) based on the graph shown in FIG. 7 based on the under-stroke change amount? S _underbraking and the over-stroke change amount? S _overbraking of the brake pedal calculated as described above have.

The graphs shown in Figs. 7 (a) and 7 (b) are constructed by previously mapping the stroke pattern of the brake pedal to the under-stroke pattern and the satisfaction of the driver's braking demand in the case of the over-stroke pattern, (D _underbraking , D _overbraking ) on the basis of the overstroke change amount (ΔSunderbraking) and the overstroke change amount (ΔSunderbraking).

According to the braking demand satisfaction map constructed for the under-stroke pattern as shown in Fig. 7 (a), the braking demand satisfaction degree (D _underbraking ) is determined to be a larger value as the under-stroke change amount [Delta] Sunderbraking of the brake pedal has a smaller value The on-demand stop score Davg increases, and as the under-stroke change amount [delta] Sunderbraking has a large value, the satisfaction of the braking demand (D _underbraking ) is determined to be a small value and the on-demand stop score (Davg) decreases. The brake demand satisfaction with the under-stroke change amount (δSunderbraking) (D _{underbraking),} the maximum value (D _{underbraking.max)} and the minimum value in (0) is set, under the stroke change amount (δSunderbraking) to a low value (δSunder.low) (D _{underbraking.max} ), and when it occurs above the high value (delta Sunder.high), it is maintained at the minimum value (0).

According to the braking demand satisfaction map constructed for the overstroke pattern as shown in FIG. 7 (b), the braking demand satisfaction _degree (D _overbraking ) becomes larger as the overstroke variation amount? S overbraking of the brake pedal becomes smaller The determined demand stop score Davg increases and the braking demand satisfaction _degree D _overbraking is determined to be a smaller value as the overstroke change amount? S overbraking has a larger value to reduce the on-demand stop score Davg . At this time, the braking demand satisfaction _degree D _overbraking with respect to the overstroke change amount? S overbraking is set such that the over-stroke change amount? S overbraking is set to the low value? S over.low because the maximum value D _{overbraking.max} and the minimum value 0 are set, (D _{overbraking.max} ), and if it occurs above the high value (delta S _over.high ), it is maintained at the minimum value (0).

In other words, as the under-stroke change amount [Delta] Sunderbraking or the over-stroke change amount [Delta] Soverbraking is smaller, the driver's braking demand satisfaction _degree (D _underbraking , D _overbraking ) is determined to be a large value and the braking demand satisfaction _degree (D _underbraking , D _overbraking ) The greater the value of the on-demand stop score (Davg) is determined to be, since it means that the driver braking demand is satisfied.

During braking, the driver typically repeats the situation of increasing the pedal depression by stepping on the brake pedal additionally, or decreasing the pedal depression of the brake pedal, more than once until the desired deceleration is achieved.

Therefore, every time the stroke fluctuation (position fluctuation) of the brake pedal occurs, the satisfaction of the driver's braking demand amount (D _underbraking , D _overbraking ) according to the stroke variation amount of the brake pedal is numerically expressed as described above.

Accordingly, when a situation in which the driver further depresses the brake pedal occurs several times (n times) during the vehicle braking, the braking demand satisfaction degree (D _underbraking ) in which the stroke variation amount (delta Sunderbraking) is quantified every time the stroke change of the brake pedal occurs _{. n} ) to calculate the first driver's braking demand satisfaction _degree (D _{underbraking.avg} ) as the calculated value, and even when a situation in which the driver during braking reduces the amount of depression of the brake pedal occurs several times (m times) The second driver braking demand satisfaction _degree (D _{overbraking.avg} ) is calculated as a value calculated by averaging the braking demand satisfaction _degree (D _{overbraking.m} ) obtained by digitizing the stroke variation amount (ΔSoverbraking) whenever the stroke variation of the pedal occurs.

The on-demand stop score (Davg) is finally determined as a value calculated by averaging the first driver's braking demand satisfaction _degree (D _{underbraking.avg} ) and the second driver's braking demand satisfaction _degree (D _{overbraking.avg} ).

The process of calculating the on-demand stop score (Davg) based on the satisfaction of the driver's braking demand (D _{underbraking.n} , D _{overbraking.m} ) can be expressed as Equation 1 below.

Equation 1:

Next, as shown in FIG. 8, calculating the economy stop score (Escore) includes: determining an optimum required deceleration for fuel economy (or for improving fuel economy); Calculating a difference value (DECdiff) between an actual deceleration of the vehicle and an optimum required deceleration for the fuel economy; And calculating an economy stop score (Escore) as a value obtained by cumulatively adding the difference value (DECdiff) generated during vehicle braking.

In the step of determining the optimum required deceleration for the fuel economy, the optimum required deceleration for fuel economy improvement based on the vehicle current position information (GPS position information), the distance information between the traffic information and the preceding vehicle, .

Specifically, the optimum required deceleration (or the 'optimum fuel-economy required deceleration') for the fuel economy is an optimum required deceleration determined in consideration of the fuel consumption relative to the driver's braking demand, so as to prevent sudden braking, Is a determined value.

Wherein the fuel economy optimum required deceleration is determined by: setting a basic recommended deceleration; Calculating a predicted distance (a predicted stopping distance) until the vehicle stops while the vehicle is running; Calculating a required deceleration (stop deceleration) until stopping based on the estimated stop distance; And determining the fuel economy optimum required deceleration based on the stop deceleration and the basic recommended deceleration.

The basic recommended deceleration is set as a constant deceleration value for improving the fuel economy during braking.

The stop estimated distance is calculated as a smaller value of the distance to the preceding vehicle and the current position of the vehicle and the distance to the intersection stop line in front of the vehicle. Such a stop estimated distance is calculated only when the preceding traffic light information is a red signal .

The stop deceleration (a) is calculated on the basis of the estimated stopping distance S and the current vehicle speed V1, and can be specifically calculated using the following equation (2).

Equation 2:

Equation 2 can be derived using the kinetic energy formula until the current vehicle speed becomes zero. That is, if V1 is the current vehicle and V2 is the vehicle speed at the stop,

And F = m * a, so that the above equation 2 is derived.

Then, the fuel economy optimum required deceleration is determined as a larger value among the stop deceleration and the basic recommended deceleration.

The difference value DECdiff between the fuel economy optimum required deceleration and the actual deceleration can be calculated by comparing the fuel consumption optimum deceleration calculated as described above with the actual deceleration of the vehicle by braking.

9, the actual deceleration by the fuel economy optimum required deceleration and the braking is variable during the vehicle braking according to the driver's demand, so that the difference between the optimum fuel consumption deceleration required during the vehicle braking time and the actual deceleration (DECdiff) are cumulatively added by integrating and integrating them to calculate an economy stop score (Escore).

As shown in FIG. 10, the calculated economy stop score (Escore) maintains the maximum value when the difference value DECdiff occurring during the vehicle braking is below a predetermined value, and when the difference value DECdiff exceeds the predetermined value Thereafter, it gradually decreases.

Next, a total stop score (a total sum) is calculated as a sum of the on-demand stop score (Davg) and the economy stop score (Escore) based on the economy stop weight (?) Determined to set a weight on the fuel consumption side among vehicle fuel economy and driver braking demand Tscore), and the total stop score Tscore is calculated as shown in Equation 3 below.

Equation 3: Tscore =? Escore + (1 -?) 占 Davg

In the step of determining the braking force correction reference, as shown in FIG. 11, the values of the on-demand stop score Davg and the economy stop score (Escore) are compared to select a braking force correction reference. Davg) is equal to or greater than the economy stop score (Escore), the driver braking demand is selected as the braking force correction reference, and when the on-demand stop score (Davg) is less than the economy stop score (Escore), the fuel economy is selected as the braking force correction reference.

When the driver's braking demand is selected as the braking force correction reference, the braking force correction learning amount is determined by reflecting the driver's braking intent, and the corrected target braking force (i.e., final braking force) is calculated based on the target braking force and the braking force correction learning amount Braking force correction value).

At this time, the braking force correction learning amount is used to correct the target braking force value corresponding to the pedal stroke on the basis of the pedal stroke when the stroke change amount is the maximum value.

In other words, the target braking force to be corrected is determined by referring to the pedal stroke before the additional brake pedal operation of the driver, which is obtained in the under braking situation and the over braking situation, is performed. If the number of times of additional operation of the brake pedal is several The target braking force in the pedal position when the stroke variation amount is the maximum is determined as the target braking force to be corrected.

When the stroke pattern of the brake pedal is an under-stroke pattern, the braking force correction learning amount is determined as a positive (+) value. When the stroke pattern of the brake pedal is an overstroke pattern, the braking force correction learning amount is determined as a minus (-) value.

The braking force correction learning amount is determined as a positive (+) value proportional to the under-stroke change amount or as a negative (-) value proportional to the overstroke change amount, since the braking force correction amount required by the driver is not satisfied as the stroke change amount increases. do.

In addition, when the fuel consumption is selected as the braking force correction reference, the braking force correction learning amount is determined so that the fuel economy can be improved in view of the fuel efficiency, not the driver's braking intent. The corrected target braking force (i.e., final braking force) And the braking force correction learning amount (braking force correction value).

At this time, the braking force correction learning amount is determined as a value proportional to the economy stop score (Escore).

In addition, the target braking force is gradually increased during the braking time to reach the final braking force (target braking force + braking force correction learned amount), and the target braking force is gradually increased during the braking time. So that the driver does not feel a sense of heterogeneity in which the feeling of change is suddenly changed.

Further, the braking force learning accumulation can be performed as the vehicle braking under the condition capable of learning the braking force is repeatedly performed. Therefore, when the braking force correction learning amount exceeds a predetermined constant value, not the target braking force but also the actual braking force can be corrected.

FIG. 12 is a graph illustrating a target deceleration varying with the stroke of a brake pedal after execution of braking force learning according to the present invention, and shows the effect obtained by the braking force control according to the present invention.

Referring to FIG. 12, Case 1 shows a case where the target deceleration relative to the initial (before braking force learning) is reduced as the target braking force decreases after learning the braking force, and Case 2 shows a case where the initial Before braking force learning) is the case where the target deceleration is reduced.

Since it is desirable to limit the range of variation through correction of the target braking force at this time, by setting the lower limit of the braking force correction learning amount that does not affect the running stability and the upper limit value that can satisfy the regulatory requirement level, The target deceleration can be limited to the minimum and maximum values of the target deceleration after the braking force learning.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. Modifications are also included in the scope of the present invention.

Claims (7)

A first step of determining whether a braking force learning for correcting a target braking force generated according to a stroke of a brake pedal is possible when a vehicle braking is required;
A second step of selecting a braking force correction criterion for determining a braking force correction learning amount of the target braking force among the driver braking demand amount and the fuel consumption ratio when the braking force learning is possible;
And a third step of performing braking force learning by correcting the target braking force using the braking force correction learning amount determined in accordance with the selected braking force correction standard,
The second step includes: calculating an on-demand stop score (Davg) indicating the degree of satisfaction of the driver braking demand;
Calculating an economy stop score (Escore) indicating a degree of satisfaction of fuel economy in a braking situation;
Calculating a total stop score (Tscore) as a sum of the on-demand stop score (Davg) and the economy stop score (Escore) based on the economy stop weight (?);
Determining a braking force correction reference during driver braking demand and fuel consumption according to a comparison result of magnitude values of an on-demand stop score (Davg) and an economy stop score (Escore) when the total stop score is less than a set reference stop score;
And a braking force control means for controlling the braking force based on the driver's braking tendency.
The method according to claim 1,
In the first step, whether the vehicle is suddenly stopped based on the deceleration of the vehicle, whether the safety distance from the front vehicle is secured according to the vehicle speed, the stroke fluctuation amount and the variation frequency of the brake pedal, whether the vehicle is located apart from the intersection by more than a predetermined reference distance, Whether the signal light signal in front is in a travelable state, whether there is a traffic sign related to a vehicle speed reduction situation on a road under driving, whether the yaw rate and lateral acceleration of the vehicle are less than a reference yaw rate and a reference lateral acceleration, And determining whether braking force learning is possible if all of the conditions for determining whether the braking force is less than the steering angle are satisfied.
delete The method according to claim 1,
The step of calculating the on-demand stop score (Davg)
Numerically expressing the degree of driver braking demand satisfaction according to the stroke variation of the brake pedal whenever stroke variation of the brake pedal occurs;
Determining an on-demand stop score (Davg) as a value obtained by averaging the calculated driver braking demand satisfaction degree;
And a braking force control means for controlling the braking force based on the driver's braking tendency.
The method according to claim 1,
The step of determining the economy stop score (Escore)
Calculating a fuel economy optimum required deceleration;
Calculating a difference value (DECdiff) between the vehicle actual deceleration and the fuel economy optimum required deceleration;
Calculating an economy stop score (Escore) as a value obtained by cumulatively adding the difference value (DECdiff) generated during vehicle braking;
And a braking force control means for controlling the braking force based on the driver's braking tendency.
The method according to claim 1,
In the step of determining the braking force correction reference,
Comparing the on-demand stop score (Davg) with the economy stop score (Escore), if the on-demand stop score is above the economy stop score, then the driver braking demand is selected as the braking force correction standard. If the on-demand stop score is below the economy stop score, Is selected as the braking force correction reference.
The method of claim 5,
The step of calculating the fuel economy optimum required deceleration includes:
(a) setting a default recommended deceleration;
(b) calculating a predicted distance until a vehicle stops while the vehicle is running;
(c) calculating a required deceleration until stopping based on the estimated distance calculated in the step (b);
(d) determining a greater value among the deceleration calculated in the step (c) and the basic recommended deceleration as the fuel economy optimum required deceleration;
The braking force control method comprising the steps of:

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