JPH0733777B2 - Vehicle drive force control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle driving force control device that suppresses slippage of drive wheels.

(Prior Art) A conventional vehicle driving force control device is disclosed in
The device described in JP-A-60-43133 is known.

This conventional device is configured to forcibly close the throttle valve and reduce the driving force when the slip ratio of the driving wheels is larger than a preset value.

(Problems to be Solved by the Invention) However, in such a vehicle driving force control device, the slip ratio between the tire and the road surface is uniquely calculated based on the detected driving wheel speed and the vehicle body speed. However, since the driving force decrease control is performed when the slip ratio becomes larger than the predetermined slip ratio threshold value,
If this slip ratio threshold value is set to a small value based on the driver who performs general gentle driving operation, it is not limited to high μ roads and low μ roads, and it is possible to drive the corners by power sliding while swinging the rear with FR cars. For drivers who prefer to
It is not interesting, and if the slip ratio threshold value is set to a large value based on the driver who likes sporty driving such as power slide, the drive wheel slip is allowed too much and the driver will not feel the accelerator. There is a lack of safety such as spin occurring during operation.

As a driving force control device that solves the above problems, there is disclosed in Japanese Patent Laid-Open No.
The device described in Japanese Patent No. 23831 has been proposed.

This conventional device enables power slide traveling by changing the slip determination value so that it increases as the accelerator pedal depression amount increases.

However, since the accelerator depression amount that changes the slip judgment value is detected by the signal from the sensor, even if the detected accelerator depression amount is the same, it was intentionally performed by a skilled driver for power slide running. I can't tell if it's a real thing or something that an inexperienced driver did.

Therefore, even if a skilled driver can achieve the purpose during intentional accelerator operation, excessive driving slip is allowed during inadvertent accelerator operation by an inexperienced driver, resulting in unstable vehicle behavior and driving safety. This creates problems in terms of sex.

In addition, if the driver recognizes that the driving force control device is installed, it is sufficient to step on the accelerator more than necessary from the sense of security that it is okay to perform a slightly rough accelerator operation. Conceivable.

(Means for Solving Problems) The present invention has been made for the purpose of solving the above problems, and in order to achieve this object, the present invention uses the following solving means.

The solution means of the present invention will be described with reference to the claim correspondence diagram shown in FIG. 1. The drive wheel speed detection means a for detecting the drive wheel speed.
A vehicle body speed detecting means b for detecting a vehicle body speed, an actual slip rate calculating means d for calculating an actual slip rate between the tire and the road surface based on the driving wheel speed and the vehicle body speed, and an accelerator operation amount at least at a predetermined time. Is the first driving operation pattern, and is the second driving operation pattern when the number of times the accelerator operating speed exceeds the set value is small due to the large accelerator operating amount in the predetermined time, and the accelerator operating in the predetermined time The number of times that the accelerator operation speed exceeds the set value due to the large amount is large,
In addition, when the second driving operation pattern is selected, the driving operation pattern detection means c which is the third driving operation pattern, and the slip ratio threshold when the detected driving operation pattern is the first driving operation pattern Is set to a small value, the slip ratio threshold is set to a large value as the operation pattern changes from the first operation pattern to the third operation pattern, and the accelerator operation speed is set to a set value when the accelerator operation amount is large for a predetermined time. Is exceeded and the first driving operation pattern is selected, the slip ratio threshold value is set to a value smaller than the threshold value set in the third driving operation pattern. Threshold setting means e
And a driving force control means f for performing a driving force reduction control to suppress a drive wheel slip when the actual slip ratio exceeds the slip threshold value.

(Operation) When the accelerator operation amount is small at least for the predetermined time, the driving operation pattern detecting means c detects that the driving operation pattern is the first driving operation pattern, and the slip ratio threshold setting means e detects the slip ratio. The threshold value is set to a small value. Therefore, the driving force control means f performs the driving force reduction control for suppressing the drive wheel slip when the actual slip ratio exceeds the slip ratio threshold value by the set small value during traveling.

In other words, it is considered that the driving operation pattern is careful and careful when the accelerator operation amount is small at least in the predetermined time. In this case, high running safety is ensured by the slip prevention control that hardly allows the drive wheel slip. To be done.

Then, the driving operation pattern detection means c detects the second driving operation pattern when the accelerator operation amount is large in a predetermined time and the number of times the accelerator operation speed exceeds the set value is small, and the slip ratio threshold setting means. At e, the slip ratio threshold value larger than that of the first driving operation pattern is set.

Therefore, the more sporty the accelerator operation, which is determined by the accelerator operation amount and the accelerator operation speed, is, the higher the allowable level of the drive wheel slip is, and the driver's acceleration request can be met.

Further, in the driving operation pattern detecting means c, the number of times the accelerator operating speed exceeds the set value is large due to the large accelerator operating amount in the predetermined time, and the third driving operation pattern is selected when the second driving operation pattern is selected. Detected as a driving pattern,
The slip ratio threshold setting means e sets the highest slip ratio threshold.

This is considered to be a skilled driver because the second driving operation pattern is selected, and it is determined that the skilled driver intentionally depresses the accelerator, and the highest slip ratio threshold value is determined. By setting it, it becomes possible to perform power slide driving, etc. that reflects the driver's intention.

On the other hand, the number of times the accelerator operation speed exceeds the set value is large due to the large accelerator operation amount in the predetermined time, but when the first driving operation pattern is selected, the slip ratio threshold setting means e causes the slip to occur. The rate threshold value is set to a value smaller than the threshold value set in the third driving operation pattern.

This is regarded as an inexperienced or cautious driver because a pattern other than the second driving pattern is selected,
When it is determined that such a driver has accidentally stepped on the accelerator, the slip stability threshold is set to a value smaller than the value set in the third driving operation pattern, whereby traveling stability is ensured.

(Examples) Examples of the present invention will be described in detail below with reference to the drawings.

In describing this embodiment, a drive force control device applied to a rear-wheel drive vehicle will be taken as an example.

First, the configuration of the embodiment will be described.

As shown in FIG. 2, the power train P of the rear-wheel drive vehicle to which the driving force control apparatus A of the embodiment is applied is the engine 1,
Transmission 11, propeller shaft 12, rear differential 13, rear drive shafts 14, 15, rear wheels 1
Equipped with 6,17.

The front wheels 18 and 19 are non-driving wheels.

The driving force control apparatus A of the embodiment mechanically disconnects an accelerator pedal 20 which is an accelerator operator and a throttle valve 22 which is provided in a throttle chamber 21 which is an intake system of the engine 10 from an accelerator control wire or the like. Accelerator pedal 20 and throttle valve instead of the mechanical connection of
22 is a control device provided between the input device and
A rear wheel rotation speed sensor 30, a right front wheel rotation speed sensor 31, a left front wheel rotation speed sensor 32, an accelerator potentiometer 33 are provided, a throttle valve control circuit 34 is provided as arithmetic processing means, and a step motor 35 is provided as a throttle actuator.

The rear wheel rotation speed sensor 30 is a drive wheel speed detecting means, is provided on the input shaft portion of the rear differential 13, and outputs a rear wheel rotation signal (vr) corresponding to the rear wheel rotation speed V _R.

An optical sensor, a magnetic sensor, or the like is used as the rear wheel rotation speed sensor 30, and when a pulse signal is output as the rear wheel rotation signal (vr), the throttle valve control circuit 34
In the input interface circuit 341 inside, the F / V converter converts to a voltage according to the frequency of the pulse signal, and the A / D converter converts the voltage value to a digital value.
342 and memory 343.

The right front wheel rotation speed sensor 31 and the left front wheel rotation speed sensor 32
Is a vehicle speed detecting means, which is provided at each axle portion of the front wheels 18 and 19, and rotates the right front wheel rotation signal (vfr) and the left front wheel rotation according to the right front wheel rotation speed V _FR and the left front wheel rotation speed V _FL. Output signal (vfl).

The signal conversion for the CPU 342 of the throttle valve control circuit 34 to read the output signals from both the front wheel rotation speed sensors 31 and 32 is performed in the same manner as the rear wheel rotation speed sensor 30.

The accelerator potentiometer 33 has an accelerator operation amount 1
Is provided at the position of the accelerator pedal 20 and outputs an accelerator operation amount signal (l) corresponding to the accelerator operation amount l.

The output signal from the accelerator potentiometer 33 is
Since it is an analog signal based on a voltage value, it is converted into a digital value by the A / D converter of the input interface circuit 341 and read into the CPU 342 or the memory 343.

The throttle valve control circuit 34 processes the input information from the input sensor and the information temporarily or preliminarily stored in the memory 343 in accordance with a predetermined arithmetic processing procedure and outputs a pulse to the step motor 35 which is a throttle actuator. An electronic circuit centered on a microcomputer that outputs a control signal (c). As internal circuits, an input interface circuit 341, a CPU (central processing unit) 342, a memory (RAM, ROM) 343, and an output interface circuit 344 are provided. I have it.

The step motor 35 is an actuator that opens and closes the throttle valve 22 and includes a rotor and a plurality of stators having an excitation winding, and a forward rotation direction and a reverse rotation direction depend on how a pulse is applied to the excitation winding. Rotate one step at a time.

Next, the operation of the embodiment will be described.

First, the flow of throttle valve opening / closing control operation in the CPU 342 will be described with reference to the flowchart of the main routine shown in FIG. 3 and the flowchart of the subroutine shown in FIG.

Note that the processing in the main routine of FIG. 3 is performed at a predetermined cycle (for example, 20
msec) is a constant time interrupt process, and the process in the subroutine of FIG. 4 is appropriately started in the main routine according to the signal output cycle to the step motor 35 determined by this constant time interrupt. oci (output compare interrupt) interrupt processing.

(B) Initial setting In the main routine shown in Fig. 3, insert the engine key into the key cylinder and turn the ignition switch from OFF to O.
Starting is started from the time of switching to N, and at the time of the first processing operation, it is judged whether it is the first time (step
100), and proceed to the next initialization step 101.

In this initialization step 101, all the information set during the previous run is cleared.

(B) Slip ratio calculation processing First, based on the input signals from the sensors 30, 31, 32, 33, the rear wheel rotation speed V _R , the right front wheel rotation speed V _FR , the left front wheel rotation speed V _FL
And the accelerator operation amount 1 are read (step 102).

In step 103, the right front wheel rotation speed V _FR and the left front wheel rotation speed
The front wheel rotation speed V _F is calculated by using V _FL .

The formula for calculating the front wheel rotation speed V _F is And is calculated by the average value.

Next, in step 104, the slip ratio S is calculated.

The calculation formula of the slip ratio S is Is.

(C) Slip ratio threshold setting process In step 105, the accelerator operation speed is calculated.

Note that the accelerator operation speed is a change amount of the accelerator operation amount 1 per unit time, for example, the accelerator operation amount ln _-1 read by the previous control activation and the accelerator operation amount ln read by the current control activation. It is calculated by the difference (ln ₋₁ −ln) or the like.

In step 106, a predetermined time (for example, 2
sec), the integrated value Σl of the accelerator operation amount l is larger than the set value k ₁ , that is, whether the driver has performed a rough accelerator operation but a delicate accelerator operation, and performed a rough accelerator operation. In this case, the process proceeds to step 112, and when a delicate accelerator operation is performed, the process proceeds to step 107.

In step 107, a predetermined time (for example, 2
sec), the number of times the accelerator operation speed exceeds the set value ₀ is counted, and it is judged whether or not the number ΣN () is larger than the set value K _2. If it is larger, the process proceeds to step 108, and if it is smaller, the process proceeds to step 110.

That is, step 108 is when "Σl is small and ΣN () is large". The accelerator operation amount l is small, and the accelerator operation speed is high in a pattern that can occur sufficiently for both skilled and inexperienced drivers ( NORMAL pattern; corresponding to the first operation pattern described in the claims), the slip ratio threshold S ₀ is 0.1
(Standard value) is set (step 109).

Step 110 is when "Σl is small and ΣN () is small", and the accelerator operation amount l is small and the accelerator operation speed is small because the pattern of a driver performing a careful driving (CAREFUL pattern; patent) Equivalent to the first driving operation pattern described in the claims), the slip ratio threshold value S ₀ is set to 0.05, which is lower than the standard value, and the stability is enhanced by making the slip detection sensitive. (Step 111).

In step 112, it is judged whether or not the count value ΣN () is larger than the set value k ₂ when it is judged that Σl is large in step 106. If it is larger, the process proceeds to step 115, and if it is smaller, step 113 Go to.

Step 113 is when "Σl is large and ΣN () is small", and the accelerator operation amount l is large and the accelerator operation speed is small because the amount of depression is close to the proper position, which is a dangerous situation. Therefore, it is a case where there is no need to perform a sudden depression or a sudden return operation, and a driver pattern (SKILL pattern; the second driving operation pattern described in the claims) which is considerably skilled at least in accelerator operation. Equivalent to),
Set the slip ratio threshold S ₀ to 0.2, which is higher than the standard value,
Acceleration performance is emphasized although slippage is allowed (step 114).

When the process proceeds to step 115, “Σl is large and ΣN
() Is large, and the accelerator operation amount l is large,
It is not possible to determine whether the accelerator operation speed is high when an inexperienced person or a careful driver inadvertently steps in, or when a skilled driver intentionally steps in. Therefore, in step 115, the operation pattern flag (PTNFLG) is read, and if PTNFLG = A, C, D, it is regarded as a pattern (DANGEROUS pattern) in which an inexperienced person or a general driver inadvertently depresses the accelerator (step 118), slip ratio threshold S ₀
Is set to 0.05, which is lower than the standard value, and the stability is enhanced by making slip detection sensitive (step 119).

On the other hand, when PTNFLG = B, a pattern in which a skilled driver intentionally depresses the accelerator greatly when, for example, a power driver runs the power slide while sliding the rear at a corner (SPORTY pattern; 3) (corresponding to the driving operation pattern 3) (step 116),
By setting the slip ratio threshold value S ₀ to 0.3, which is much higher than the standard value, a considerable amount of slip is allowed and a characteristic that allows power sliding is obtained (step 117).

(D) Driving force control process First, in step 120, the actual step number STEP used in the process described later is read.

In step 121, the slip ratio S is the same as in steps 109 and 11 above.
It is determined whether or not the slip ratio threshold S ₀ set in 1,114,117,119 is exceeded, and if S ≦ S ₀ is determined to be NO, the routine proceeds to step 122 as a normal control pattern, and the accelerator read in step 102 is selected. Based on the manipulated variable 1, the target step number STEP * is calculated as a value indicated by the characteristic line described in the step.

If S> S ₀ in step 121 and YES is determined, the routine proceeds to step 123, where slip suppression control for closing the throttle valve 22 in the fully closing direction is performed as a slip suppression control pattern, and therefore the target step number STEP * Is set to zero.

In step 124, the deviation ε is calculated by subtracting the actual step number STEP from the target step number STEP *, and the motor speed of the step motor 35 is calculated, forward, reverse, and held based on the deviation ε obtained by this calculation. Of the oci interrupt routine and the start cycle of the oci interrupt routine are calculated (step 125), and the step motor set in step 125 is set.
According to the operation control contents of 35, the oci interrupt routine (4th
Figure) is activated (step 126).

Next, the flowchart of the oic interrupt routine will be described with reference to FIG.

First, a determination is made as to whether or not a hold command output for holding the state of the step motor 35 as it is is being output (step 300),
When the holding command is output, the stator side excitation state of the step motor 35 is held (step 301).

When the hold command is not output, the step motor 35
It is determined whether or not the reverse rotation command for reversing is output (step 302). When the reverse rotation command is output, S
TEP is set to STEP-1 (step 303), and the pulse signal for obtaining STEP-1 is output to the step motor 35 (step 301). Further, at the time of outputting a normal rotation command for rotating the step motor 35 in the normal direction, STEP is set to STEP + 1 (step 304) and a pulse signal for obtaining STEP + 1 is output to the step motor 35 (step 301).

The oci interrupt routine is repeated within the start cycle of the main routine according to the start cycle set in step 117.

Next, the operation during traveling will be described.

By the control processing operation described above, when the slip ratio is S ≦ S ₀ and the drive wheel slip does not occur during traveling,
The flow of the normal control pattern proceeds from step 121 to step 122 → step 124, and the throttle valve 22 is controlled to be opened / closed to an opening degree corresponding to the depression position of the accelerator pedal 20.

When the vehicle is starting, accelerating, traveling on a low friction coefficient road, etc., and the slip ratio is S> S ₀ , and the drive wheel slip is occurring, the slip suppression proceeds from step 121 to step 123 → step 124. The flow of the control pattern follows, and the drive wheel slip is suppressed by the closing operation of the throttle valve 22.

In this way, the control for starting and releasing the control for slip suppression is performed by comparing the slip ratio S obtained by calculation with the slip ratio threshold S ₀ set by the driving operation pattern, and this slip ratio threshold S ₀ The control start timing and control release timing for slip suppression are determined depending on the setting of.

Therefore, in the embodiment, in step 106 to step 119, it is determined whether or not the integrated value Σl of the accelerator operation amount l at a predetermined time (for example, 2 sec) which is set in advance is larger than the set value k _1. Predetermined time (for example, 2 sec)
The operation pattern is detected by comparing whether the count value ΣN (i) of the number of times the accelerator operation speed i exceeds the set value i ₀ is larger than the set value k ₂ and judging the operation pattern flag PTNFLG. Different patterns are divided into cases, and the slip ratio threshold S ₀ that is most suitable for each pattern is set.

The following table shows each operation pattern.

Therefore, in the embodiment apparatus, the slip prevention control which emphasizes safety is dealt with for the careful driving operation, while the sport running is allowed by allowing a certain amount of slip for the sporty driving operation. Therefore, it is possible to achieve optimum driving force control while coping with various driving operation patterns.

Further, even for an inexperienced driver or a general driver's operation on the accelerator, it is possible to prevent a dangerous situation such as a spin by judging the previous operation flag PTNFLG.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like within a range not departing from the gist of the present invention. included.

For example, although the example of the throttle valve opening / closing control device is shown as the driving force control means in the embodiment, a fuel cut device is used, or in addition, the engine output is reduced by adjusting the ignition timing, or the wheel is braked. Even if other means such as applying braking force is used, or the driving force is reduced by a combination means, the driving force to the wheels is further controlled by the engagement control of the operation limiting clutch and the 4WD transfer clutch. The present invention is also advantageous in a means for reducing

Further, the steering angle may be detected and the control as in this embodiment may be performed only during cornering.

Further, as the throttle opening / closing control, a device for suppressing slip by map drop control as described in the specification of Japanese Patent Application No. 61-157389 filed by the applicant of the present application may be used.

(Effects of the Invention) As described above, in the vehicle driving force control device of the present invention, the first driving operation pattern is set when the accelerator operation amount is small at least in the predetermined time, and the first driving operation pattern is set in the predetermined time. When the accelerator operation amount is large and the number of times the accelerator operation speed exceeds the set value is small, the second driving operation pattern is set,
Driving operation pattern detecting means for setting the third driving operation pattern when the accelerator operating speed is large for a predetermined time, the number of times the accelerator operating speed exceeds the set value is large, and the second driving operation pattern is selected. When the detected driving operation pattern is the first driving operation pattern, the slip rate threshold value is set to a small value, and the slip rate threshold value is changed as the first driving operation pattern changes to the third driving operation pattern. The slip ratio threshold is set when a large value is set, the number of times the accelerator operation speed exceeds the set value due to a large accelerator operation amount in a predetermined time, and the first driving operation pattern is selected. Since the device is provided with the slip ratio threshold value setting means for setting the value smaller than the threshold value set by the third driving operation pattern, the following effects are listed. It can be achieved.

(1) Judgment of driving operation in a plurality of patterns from careful driving operation to sporty driving operation, and the more slippery driving operation is, the larger the slip ratio threshold value is, so it corresponds to various driving operation patterns. However, optimum drive force control can be performed.

(2) The third driving operation pattern is selected when the second driving operation pattern is selected because the third driving operation pattern is selected only when two conditions, that is, the accelerator operating condition and the second driving operation pattern are selected. Therefore, it is possible to judge that a skilled driver intentionally stepped on the accelerator, and reflect the driver's intention to enable power slide or the like.

(3) The accelerator operation condition is the third operation pattern, but when the first operation pattern is selected, the slip ratio threshold value is set to a value smaller than the value set in the third operation pattern. Therefore, it is possible to judge that an inexperienced person or a careful driver has inadvertently stepped on during the selection of the first driving operation pattern, tighten the slip generation allowance, and ensure running stability. it can.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims showing a vehicle driving force control device of the present invention, FIG. 2 is an overall view showing a driving force control device of an embodiment of the present invention, and FIG. 3 is a throttle valve control circuit of the embodiment. Flowchart diagram showing a main routine of control operation, fourth
The drawing is a flow chart showing a subroutine of control operation in the throttle valve control circuit of the embodiment. a: driving wheel speed detecting means b: vehicle body speed detecting means c: driving operation pattern detecting means c1: first driving operation pattern c2: second driving operation pattern c3: third driving operation pattern d: actual slip ratio calculating means e: slip ratio threshold setting means f: driving force control means

Claims (1)

[Claims] 1. A drive wheel speed detecting means for detecting a drive wheel speed, a vehicle body speed detecting means for detecting a vehicle body speed, and an actual slip ratio between a tire and a road surface calculated by the drive wheel speed and the vehicle body speed. The slip ratio calculation means and the first operation pattern when the accelerator operation amount is small at least in a predetermined time, and when the accelerator operation amount is large in the predetermined time and the number of times the accelerator operation speed exceeds the set value is small. The second driving operation pattern is the third driving operation when the accelerator operation amount is large in a predetermined time, the number of times the accelerator operating speed exceeds the set value is large, and the second driving operation pattern is selected. The driving operation pattern detection means that is a pattern, and when the detected driving operation pattern is the first driving operation pattern, the slip ratio threshold value is set to a small value,
The slip ratio threshold value is set to a larger value as the driving operation pattern becomes the third driving operation pattern, and the number of times the accelerator operating speed exceeds the set value due to a large accelerator operating amount in a predetermined time, and A slip ratio threshold value setting means for setting the slip ratio threshold value to a value smaller than the threshold value set in the third driving operation pattern when the first driving operation pattern is selected; A driving force control device for a vehicle, comprising: a driving force control means for performing a driving force reduction control for suppressing a driving wheel slip when the rate exceeds the slip rate threshold value.