JP2907861B2 - Road surface condition detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road surface condition detecting device for detecting whether or not a road μ (friction coefficient) on right and left roads is a split road having different roads.

(Prior art) The prevention of excessive slip of the drive wheels on the road surface during acceleration or the like is necessary in order to effectively obtain the propulsion of the vehicle and to prevent the vehicle body from spinning. It is effective. Then, in order to prevent the slip of the drive wheel from becoming excessive, the torque applied to the drive wheel that causes the slip may be reduced.

Japanese Patent Application Laid-Open No. 58-16948 and Japanese Patent Application Laid-Open No. 60-56662 disclose conventional slip control or traction control. Both of the techniques disclosed in these publications reduce the torque applied to the drive wheels by using a braking force applied to the drive wheels by a brake and reducing the generated torque of the engine itself. Has become. More specifically, Japanese Patent Application Laid-Open
In the device disclosed in JP-A-16948, when the slip of the driving wheel is small, only the braking of the driving wheel is performed, and when the slip of the driving wheel is large, in addition to the braking of the driving wheel, the torque generated by the engine is added. Is to be reduced. Further, in Japanese Unexamined Patent Publication No. 60-56662,
When only one of the left and right drive wheels has a large slip, braking is performed on only one of the drive wheels having a large slip, while when both the left and right drive wheels have a large slip, the brake is applied to both drive wheels. In addition to braking, the generated torque of the engine is reduced. As described above, those disclosed in the above publications mainly use braking of the drive wheels by the brake, and reduce the torque generated by the engine in an auxiliary manner.

(Problems to be Solved by the Invention) By the way, there are a split road and a uniform road on a road surface on which an automobile runs. The uniform road has a μ on the left and right road surfaces, that is, μ on the ground surface of the left drive wheel and a μ on the ground surface of the right drive wheel.
And the split road is a case where the right and left road surfaces μ are different from each other. Knowing whether or not the road is a split road is important for effectively propelling a vehicle. For example, when performing the above-described traction (slip) control by adjusting the generated torque of the engine, the control target wheel is selected as a low μ-side drive wheel or a high μ-side drive wheel. In addition, the running state of the automobile is greatly changed. In addition, for example, in the case of a four-wheel drive vehicle in which torque can be independently distributed to four wheels, knowing whether or not the vehicle is on a split road is a factor in determining how to perform torque distribution. It becomes important.

(Object of the Invention) The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a road surface state detection device capable of accurately determining whether or not a road is a split road. I do.

(Structure and operation of the invention) In order to achieve the above-mentioned object, the present invention has the following structure. That is, left rotation detection means for detecting the rotation speed of the left drive wheel, right rotation detection means for detecting the rotation speed of the right drive wheel, and receiving the output from both the detection means, the rotation speed of one drive wheel is Within a predetermined time from the point of occurrence of the spin that becomes larger than the rotation speed of the other drive wheel by a predetermined value or more, the spin is generated again in the one drive wheel, and the rotation speed of the other drive wheel is changed within the predetermined time. Determining means for determining that the road is a split road on condition that the road has not risen by a predetermined value or more.

In the present invention configured as described above, basically, when so-called spin occurs when one rotation speed of the left and right driving wheels is higher than the other rotation speed by a predetermined value or more, the rotation speed of the left or right drive wheel is higher. Is estimated to be a split road having a low μ on the drive wheel side.

In addition, in order to provide certainty by the above basic estimation, a determination condition that a spin is generated again in the same drive wheel within a predetermined time after the spin is generated is added.

Further, in order to further increase the certainty factor, a determination condition that the rotation speed of the other drive wheel does not increase by a predetermined value or more within a predetermined time is added.

Note that an example in which the rotation speed of the other drive wheel has increased by a predetermined value or more can be when a slip occurs in the other drive wheel, as shown in an embodiment described later. More specifically, when the rotation speed of the other drive wheel is higher than the rotation speed of the one drive wheel by a predetermined amount (2 to 3 km / h as described in the following embodiments). In addition, it is possible to set the time when the rotation speed of the other drive wheel increases by a predetermined value or more.

(Effect of the Invention) As described above, according to the present invention, it is possible to accurately determine whether or not a road is a split road.

(Example) Hereinafter, an example of the present invention will be described with reference to the attached drawings. In the embodiment, a vehicle that performs traction control (slip control) uses a determination result as to whether or not the vehicle is on a split road in order to more appropriately perform the traction control.

In FIG. 1, a vehicle A has left and right front wheels 1FL and 1FR as driven wheels, and left and right rear wheels 1RL and 1RR as driving wheels. That is, the generated torque of the engine 2 mounted on the front of the vehicle body is changed by the vehicle transmission 3, the propeller shaft 4,
After passing through the differential gear 5, the power is transmitted to the left rear wheel 1RL via the left drive shaft 6L, while being transmitted to the right rear wheel 1RR via the right drive shaft 6R.

Related to Transmission The automatic transmission 3 includes a torque converter 11 and a multi-stage transmission gear mechanism 12. This transmission gear mechanism 12
Is hydraulically actuated as is known, and in the embodiment, is for four forward speeds and one reverse speed. That is, gear shifting is performed by changing the combination of excitation and demagnetization of the solenoid 13 incorporated in the hydraulic circuit. The solenoid 13 is controlled by a shift control unit UAT. The control unit UAT stores two types of shift characteristics as shown in FIGS. 4A and 4B in advance,
A shift, that is, upshifting or downshifting, is performed based on one of the shifting characteristics. Of the two types of shift characteristics, the one shown in FIG. 4A is used for normal running, that is, during non-traction control. Also, 4B
The one shown in the figure is used only during traction control. More specifically, each shift characteristic is set with the vehicle speed and the throttle opening as parameters.
The shift characteristics of FIG. 4B are different from those of FIG.
It is set so as not to have a shift line with the speed and to offset all the shift speeds to the low vehicle speed side as a whole and to increase the torque applied to the drive wheels.

The control unit UAT receives inputs from a throttle opening signal and a vehicle speed signal (in the embodiment, a rotation speed signal of the propeller shaft 4) from the sensors 61 and 62, and also receives from a traction control control unit UTR described later. Receive output. That is, only when a signal indicating that the traction control is being performed is input from the control unit UTR, the shift control is performed based on the shift characteristics of FIG. 4B, and at other times, the shift control is performed based on the shift characteristics of FIG. 4A. Do.

Brake fluid pressure adjustment relation Each wheel 1FR to 1RR is provided with a brake 21FR to 21RR. The calipers (wheel cylinders) 22FR to 22RR of the brakes 21FR to 21RR are connected via pipes 23FR to 23RR.
The fluid pressure adjusting units 24 are individually connected to each other. The hydraulic pressure is supplied to the hydraulic pressure adjusting unit 24 from a master cylinder 26 as a hydraulic pressure generation source that generates hydraulic pressure by a depression operation of a brake pedal 25 via a pipe 27. In addition, the hydraulic pressure adjusted by the pump 28 from the reservoir tank 29 by the pump 28
, And can release the hydraulic pressure to the reservoir tank 32 via the pipe 31.

The hydraulic pressure adjusting unit 24 is provided for each of the pipes 23FL to 23RR.
Each of the solenoid valves has the following operation. First, a state in which the hydraulic pressure generated in the master cylinder 26 is transmitted to each of the brakes 21FL to 21RR as it is. At this time, the brake operation is completely the same as normal brake operation, and the brake fluid pressure to each of the brakes 21FL to 21RR is independently controlled regardless of the magnitude of the fluid pressure generated at the master cylinder 26. It can also increase and decrease the pressure. Control for increasing and decreasing the brake fluid pressure is performed by the ABS control unit UABS.

Signals from the sensors 63 to 66 that detect the rotational speeds of the wheels 21FL to 21RR are input to the ABS control unit UABS. Then, the control unit UABS basically reduces the brake fluid pressure for the wheel in the locked state when detecting the locked state of each of the wheels 21FL to 21RR for controlling the anti-brake lock. Then, when the wheel returns to the unlocked state, the brake fluid pressure is increased again. Further, during traction control by the traction control control unit UTR, the rear wheels 21RL and 21RR as drive wheels receive signals from the traction control.
Control for supplying brake fluid pressure as appropriate.

Engine generated torque adjustment The traction control control unit UTR is driven by 21F drive wheels.
In order to reduce the torque applied to the L and 21RR, brakes are applied to the drive wheels 21FL and 21RR via the ABS control unit UABS, and the torque generated by the engine is also reduced. For this reason, during the linkage mechanism between the throttle valve 42 and the accelerator pedal 43 provided in the intake passage 41 of the engine,
A throttle opening adjustment mechanism 44 is interposed.

The throttle opening adjustment mechanism 44 will be described with reference to FIG. First, first, second, and third levers 112, 113, and 11 that can be slid in the left and right directions in the figure, respectively.
The first lever 112 is connected to the accelerator pedal 43 via an accelerator wire 112a, and the second lever 113 is connected to the throttle valve 41 via a throttle wire 112t. The second lever 113 is provided with a return spring 121
As a result, the throttle valve 41 is biased rightward in the drawing, that is, in the direction in which the throttle valve 41 is closed.

The third lever 114 has a first locking portion 114a that can contact the first lever 112 from the right side in the drawing, and a second locking portion that can contact the second lever 113 from the right side in the drawing. A portion 114b.
A first spring 116 is provided between the first lever 112 and the third lever 114 so as to bias the first locking portion 114a in a direction in which the first locking portion 114a contacts the first lever 112. Further, between the second lever 113 and the third lever 114, a second locking portion 11 is provided.
A second spring 122 that urges 4b in a direction in which it contacts the second lever 113 is stretched. The urging force of the first spring 116 is set larger than the urging forces of the second spring 122 and the return spring 121.

The first lever 112 is provided with a locking portion 112a at a position on the right side of the second lever 122 in the drawing, whereby the second lever 122
The relative displacement of the first lever 112 relative to the first lever 112 to the right in the drawing by a predetermined amount or more is restricted.

A pressing lever 111 is disposed on the left side of the third lever 114 in the drawing. The pressing lever 111 is driven in the left-right direction in the figure by a motor 106, and the leftward movement by a predetermined amount or more is regulated by contacting the stopper 123.

The operation of the throttle opening adjusting mechanism 44 configured as described above will be described.

First, there is a state in which the pressing lever 111 is in contact with the stopper 123. At this time, since no external force acts on the third lever 114, the first to third levers 112, 113, and 114 are
As shown in FIGS. 7A and 7B, the throttle opening is always integrated, and a throttle opening corresponding to the accelerator opening can be obtained. 0-100% changed). FIG. 2 (a) shows the case where the throttle opening is 0% (the accelerator opening is also 0%), and FIG. 2 (b) shows the case where the throttle opening is 75% (the accelerator opening is also 75%).
Is shown. In the case of FIG. 2 (b), there is still a gap between the pressing lever 111 and the third lever 114, and this gap is a margin for changing the throttle opening from 75% to 100%. Yes, when the throttle opening reaches just 100% (when the accelerator opening reaches 100%),
The third lever 114 is lightly abutted against the pressing lever 111.

When the pressing lever 111 is driven by the motor 106 in the direction shown in FIG. 2B from the state shown in FIG. 2B, the third lever 114 is forced against the first spring 116 as shown in FIG. Is moved to the right. Thus, the throttle opening is returned to the closing direction even if the accelerator opening is the same.
FIG. 2 (c) shows a state where the throttle opening is returned until the throttle opening is fully closed when the accelerator opening is 75%. At this time, the locking portion 112a of the first lever 112 is moved to the second position. Lever 1
Touched to 13.

From the state of FIG. 2 (c), the accelerator opening is set to 100% as shown in FIG. 2 (d). At this time, the first lever 112 is moved leftward in FIG.
a moves the second lever 113 to the left in the figure. As a result, the throttle opening changes from 0% in FIG. 2 (c) to 25% in FIG. 2 (d).

As described above, in this embodiment, at least the throttle valve 42 can be opened up to 25% by the accelerator full-opening operation.
Even when 111 sticks (sticks), it is possible to run on its own, such as going to a repair shop.

Overview of Traction Control The traction control control unit UTR includes a brake control via the ABS control unit UABS and a motor of the throttle opening adjustment mechanism 44 for traction control.
The engine control by controlling 106 and the shift control via the shift control unit UAT are performed. The control unit UTR includes sensors 63 to 6 for detecting each wheel speed.
6, a throttle opening signal from the sensor 67, an accelerator opening signal from the sensor 68, and an opening signal of the motor 106 from the sensor 69 are input in addition to the signal from the ABS control unit UABS. .

FIG. 3 shows the contents of the traction control by focusing on the engine control and the brake control. In FIG. 3, the driven wheel speed (sometimes expressed as the vehicle speed by an arithmetic mean of the rotational speeds of the left and right front wheels) is indicated as WFN,
The spin determination value as the first determination value is shown as WFN + 10, the spin convergence determination value as the second determination value is shown as WFN + 3, and the target slip value for the engine is SET (WFN + Δ
E), and set the brake target slip value to SBT (WFN
+ ΔB). The motor opening in FIG. 3 is 100% at the position shown in FIG. 2 (a) and 0% at the position shown in FIG. 2 (c).

The magnitude relationship between each of the above-mentioned determination values and the target value is, in order from the largest to the smallest, a spin determination value (first determination value), a brake target value, an engine target value, and a spin convergence determination value (second determination value). It is set to be.

The assumption that the, t ₀ at the time an acceleration is fully open (throttle opening, even 100% motor opening), the slip value of the driven wheels at this time exceeds the spin determination value. At this time, the throttle opening (motor opening) is reduced to SM at a stroke, and the brake fluid pressure is also increased in order to quickly converge the large slip of the drive wheels. This t ₀ point from a predetermined time (e.g. 0,5 sec) elapsed time point t _1, the slip value of the driven wheel is convergence criterion value (WFN + 3)
It is when it is still bigger than. At this time, the throttle opening is gradually reduced. While we perform the gradual comprising such reduction in the throttle opening, t ₂ time, the slip value target slip value SB brake of the driven wheel
Since it becomes T or less, the brake fluid pressure is reduced to almost zero. Then, the slip value of the driven wheel at t ₃ time is convergence criterion value (WFN + 3). This t ₃ point, so as to avoid giving a deceleration feeling caused by the applied torque reduction to the drive wheels, the throttle opening recovery opening FI
It is enlarged all at once to AG. Thereafter, feedback control is performed so that the slip value of the drive wheel becomes the target slip value SET for the engine. By the accelerator is returned significantly during this feedback control, the accelerator opening and the throttle opening and the motor opening angle are matched t ₄ time, the accelerator opening is fully closed eventually decreased further thereafter. The t ₄ time after the throttle opening degree becomes zero both eventually is reduced with a decrease in the accelerator opening. Further, the motor opening is increased, and the motor fully opens (the pressing lever 111 contacts the stopper 123).

Details of Traction Control (Flowchart) Now, details of the traction control will be described with reference to the flowcharts of FIGS. In the following description, P or Q indicates a step.

Main (Fig. 8) After the system is initialized in P1, when it is confirmed in P2 that the predetermined measurement timing is reached, P3
In, signals from the sensors 62 to 69 are read.

At P4, a spin determination is made,
This is for determining how the actual slip values of the left and right driving wheels 1RL and 1RR are positioned with respect to the spin determination value and the spin convergence determination value in FIG.

In P5, it is determined whether or not the currently traveling road surface is a split road. That is, it is determined whether or not the road is a split road in which μ (friction coefficient) of the road surface on which the left drive wheel 1RL is in contact with the ground is greatly different from μ of the road surface on which the right drive wheel 1RR is in contact with the ground. Things.

In P6, the determination of the start and the end of the traction control are performed.

In P7, μ of the currently running road surface is estimated.

In P8, it is determined whether or not traction control is currently being performed. If the determination in P8 is YES, and it is confirmed in P9 that it is the engine control timing, the target position of the motor indicating the engine control amount, that is, the magnitude of the throttle opening, is determined in P10. Subsequently, when it is confirmed that P11 and the timing for performing the brake control have been confirmed, in P12, the brake control amount, that is, the magnitude of the braking force to be applied to the drive wheel 1RL or 1RR is determined. Then, the control amount determined in P10 and P12 is
Output at P13 or P14.

If the determination in P8 is NO, in P16, the target position of the motor is set to 100% (the state of FIG. 2A), and then the flow shifts to P13.

After P13 and P14, in P15, the gearshift control, more specifically, as the gearshift characteristic, whether to use the normal gear shown in FIG. 4A or the gear for traction control shown in FIG. 4B A command signal is output to a control unit UAT for speed change control.

9 (P4 in FIG. 8) In P21, the arithmetic mean value of the rotational speeds WFL and WFR of the left and right drive wheels is determined by the driven wheel speed (vehicle speed) WF for traction control.
Set as N.

After P21, when the determination of either P22 or P23 is YES, that is, one of the rotation speeds WRL and WRR of the left and right drive wheels is determined to be larger than the spin determination value (equivalent to WFN + 10 km / h). If so, proceed to P24. At P24, it is determined whether or not the timer flag is 0. If the determination is YES, the timer value is reset to 0 at P25, the timer flag is set to 1 at P26, and further at P27. The spin flag is set to 1 to indicate that a slip larger than the spin determination value (WFN + 10) has occurred. The processes of P24, P25, and P26 are pre-processes for counting a set time from when the slip value of the drive wheel becomes the spin determination value (WFN + 10).

If the determination in P24 is NO, the timer counts up in P28, and then the timer count value is 500 ms in P29.
It is determined whether it has become larger than ec. This is the case of NO in the determination of P29 and directly proceeds to P27, also If YES in P29, the P30, to indicate that Figure 3 t ₀ a predetermined time from the time (500 msec) has elapsed, time After the flag is set to 1, the flow shifts to P27.

If the determinations in P22 and P23 are both NO, in P31, it is determined whether or not the rotation speed WFL of the left driving wheel 1RL has become smaller than the spin convergence determination value (equivalent to WFN + 3 km / h). If the determination in P31 is YES, the spin flag is reset to 0 in P33. Also, N in the determination of P31
In the case of O, it is determined in P32 whether or not the rotation speed WRR of the right drive wheel RR is smaller than the spin convergence determination value (WFN + 3). If the determination is YES, the spin flag is set to 0 in P23 described above. Reset.

When the determination in P32 is NO and after P33, the timer flag is reset to 0 in P35 after the time lapse flag is reset to 0 in P34.

After P35, and after P27, at P36,
Whether it is immediately after the spin occurs, i.e. whether it is immediately after past the t ₀ point in Figure 3 is determined. When the determination in P36 is YES, the flag JF is set to 1 in P36. If the determination in P36 is NO, it is determined in P37 whether or not it is immediately after spin convergence, that is, whether or not it is immediately after the time point t3 in FIG. _{3. If} the determination is YES, P40
The flag JF is set to 2. NO in the judgment of P37
, The flag JF is reset to 0 in P39.

FIGS. 10A to 10D, FIG. 21 (P5 in FIG. 8) Whether the roads of the right and left driving wheels are split roads having different μ (friction coefficient) on the ground surface, or are uniform roads having the same μ. Is to be determined. No.
FIG. 21 is a time chart for easily understanding the relationship between various flags and timers used in the flowcharts of FIGS. 10A to 10D. In this time chart, although the right drive wheel has a second spin again within a predetermined time from the first spin of the right drive wheel, the left drive wheel has spin generated within the predetermined time. Therefore, the case where the determination that the road is the split road is not finally made is shown.

Since a large number of flags are used in FIGS. 10A to 10D, the meaning of each flag will be described first, and a timer for managing a predetermined time will be described. In addition,
In the description of FIGS. 10A to 10D, for simplicity, a state in which one of the left and right drive wheels causes a large slip of a predetermined value or more with respect to the other drive wheel is referred to as “spin occurrence”. Express. Therefore, occurrence of spin in the right driving wheel means that the right driving wheel has slipped by more than the predetermined value with respect to the left driving wheel.

“Flag SPRF” indicates the spin generation state of the right driving wheel, and indicates “1” when spin occurs.

"Flag SPLF" It corresponds to SPRF and is for the left drive wheel.

“Flag SPRFO” is for the right drive wheel and indicates the previous state of the flag SPRF, and is used to distinguish between the first spin generation and the second spin generation. This SPRFO becomes 1 while the flag SPRF falls (becomes 0) and the timer SPRTM counts down. The timer SPRTM becomes 0 or 0 when the next spin occurs.

"Flag SPLFO" Corresponds to the flag SPRFO and is for the left drive wheel.

“Flags SPLR and SPLL” SPLR indicates the possibility that the right road surface is lower μ than the left road surface, and SPLL indicates the possibility that the left road surface is lower μ than the right road surface. Both flags are displayed in hexadecimal notation, and the meaning of the display is as follows. Note that “H” in the following “00H” and the like is an identification code indicating that it is in hexadecimal.

00H: Used for both SPLR and SPLL, during the first spin generation or during timer down count (predetermined time measurement)
Means inside.

01H: Dedicated to SPLR (for right side), indicating that the right side may be a low μ road. That is. Right drive wheel is part 1
It is set to 01H when the second spin is generated within a predetermined time after the first spin is generated.

02H: Dedicated to SPLL (for left side), indicating that the left side may be a low μ road.

80H: Used for both SPLR and SPLL, indicating no spin generation.

The SPLL and SPLR as described above are used to determine whether or not the road is finally a split road by looking at the added value. That is, in order to determine that the road is the split road, at least the added value of the two flags SPLL and SPRL is 81H or 82H. More specifically, SP
One of LL and SPRL indicates no spin 80
H, and the other is 01H or 02H. Therefore, 81H
Or 82H, it is possible to determine which of the right and left road surfaces has a low μ.

"Timer SPRTM" For the right driving wheel, counts the time from spin generation to convergence as shown in FIG. Then, a predetermined time is set by multiplying the counted time by K times (K> 1). In other words, in the present embodiment, the predetermined time is changed according to the time from spin generation to convergence. This timer SPRTM
From the time when the flag SPRF falls (becomes 0)
Start down counting (measurement of a predetermined time).

"Timer SPLTM" This is for the left drive wheel and corresponds to the timer SPRTM.

"Flag CNCRP" For the right drive wheel, when the right drive wheel is spinning, or before the timer SPRTM becomes 0, it is set to 1 when the left drive wheel spins, and is a split road. Is used as data for negating the determination.

"Flag CNCLP" It corresponds to the flag CNCRP and is for the left drive wheel.

"Flag CNCSP" is used as final data for negating the determination that the road is a split road, and is set in accordance with both the flags CNCRP and CNCLP. When the flag is 1, the determination that the road is a split road is denied. .

"Flag CNCF" This is used to deny the determination that the road is a split road. This CNCF is performed to deny the determination that the road is a split road until the second spin convergence is completed. More specifically, in the α region of FIG. 21, there is a possibility that the added value of SPLL and SPRL becomes 81H and an erroneous determination that the road is a split road occurs (see FIG. 21). SPLT is erroneously set to 1 as shown as β), and setting the CNCF prevents the erroneous determination.

“Flag SPLT” indicates a final determination result as to whether or not the road is a split road, and a value of 1 means that the road is a split road. In the embodiment, the determination result of the flag SPLT is used for changing the target slip value for the engine, as shown in FIGS.

“Flag SPW” indicates whether the right or left road surface is low μ when a split road is determined. When 1, the right road surface is low μ, and when 0, the left road surface is low μ. Is shown.

On the premise of the above, FIGS. 10A to 10D will be described with reference to the time chart of FIG.
In the following description, Y indicates a step.

First, the spin generation state of the right driving wheel and the spin generation state of the left driving wheel are identified by the processing of Y1 to Y6 in FIG. 10A. That is, the right drive wheel speed is determined by the processing of Yl to Y3.
When WRR is larger than left driving wheel speed WRL by a predetermined value ΔN or more, flag SPRF is set to 1 in Y2 because spin occurs in the right driving wheel, and flag SPRF is reset to 0 in Y3 otherwise. . Similarly, the processing of Y4 to Y6 sets and resets the left driving wheel flag SPLF. The above ΔN is a predetermined value serving as a threshold value for determination of spin occurrence, and the magnitude of ΔN is 2-3 k in the embodiment.
m / h.

In Y7, it is determined whether or not the current time is determined to be a split road. If the determination is NO, the control shown in FIG. 10D is performed via Y8 and Y9.

Y8 and Y9 are processes for sequentially estimating that the left and right road surfaces are at low μ, and details of Y8 are shown in FIG. 10B and details of Y9 are shown in FIG. 10C. FIG.10B showing the details of Y8 is, after all, what value the flag SPLR, which is the data for split road determination, is set to, ie, 00
H, 01H, or 80H is set. That is, assuming that the determination in Y21 is YES, that is, the timer SPRTM is 0, the route passing through Y21, Y22, and Y23 is the second route.
The ones until time point t ₁ of Figure 1. Also, from Y21 through Y22, Y
Optimum route 24, is when it becomes just time point t ₁ in Figure 21.

If the determination in Y21 is NO, the process reaches Y25. When the determination in Y25 is YES, the process proceeds to Y30, but after this Y30, Y33
Optimum route to Y24 is, becomes up to t ₁ ~t ₃ time points Figure 21.

If NO in the determination of Y25, that is, when no slip current right driving force generated, the processing after Y26 is made, the time ranging from Y26 to Y28 becomes just t ₃ time points in FIG. 21 It is time. The route from Y26 to Y27 is
Corresponds to up to t ₃ ~t ₆ time points Figure 21.

The time when passing through Y30 from Y30 is exactly t _{6 in} FIG.
At this point, the route from Y30 through Y33 to Y32 is
Corresponding to t ₆ after the 1 FIG.

FIG. 10C showing the details of Y9 is for the left drive wheel,
Corresponding to FIG. 10B, and a duplicate description thereof will be omitted. Of course, in FIG. 10C, the flag SPLL which is the split road determination data is set, but the SPLL is set to one of 00H, 02H, and 80H as described above.

After Y9, the processing in FIG. 10D is performed. First, Y61 to Y6
By the processing in step 6, focusing on the right driving wheel, a flag is used as data indicating whether or not to deny the determination that the road is a split road.
The setting process of 1 or 0 of CNCRP is performed. That is,
If spin occurs on the left drive wheel within a predetermined time, it must not be determined that the vehicle is on a split road. In that case, CNCRP is set to 1 in Y64.

At Y67 to Y72, processing similar to the above Y61 to Y66 is performed by focusing on the left driving wheel (CNCLP setting processing).

In Y73, it is determined whether one of the CNCRP and the CNCLP set as described above is “1”. When the determination in Y73 is YES, the determination that the road is a split road is prohibited. In this case, the CNCP is set to 1 in Y74, and when the determination in Y73 is NO, the CNCS is determined in Y75.
P is reset to 0.

After Y74 or Y75, a flag indicating the result of determination as to whether or not the road is finally a split road by the processing after Y76.
SPLT setting processing is performed. That is, the final determination of the split road (SPLT is set to 1) is made up of SPLR and SPLL.
Assuming that the added value with is 81H or 82H, CN
Only when CF is not 1 and CNCP is not 1.

When the determination in Y7 of FIG. 10A is YES, that is, when it is determined that the vehicle is currently on the split road, it is first determined in Y10 whether the flag SPLTF is 1. This flag SPLTF indicates whether or not it has already been determined whether the left or right road surface is a low μ road, and is set to 1 when this determination is made. Therefore, initially Y10
Is NO, and the processing of Y11 to Y14 determines whether the left or right road surface is low μ (SPW = 1).
, The right road surface is low μ, and when SPW = 0, the left road surface is low μ).

If the determination in Y10 is YES, the processing on Y15, Y16, and Y18 causes a spin on the left drive wheel when the right road surface is low μ (SPW = 1), and a low μ road on the left road surface. In (SPW = 0), when a spin occurs in the right driving wheel, it is determined that the roads have returned to the uniform roads, and reset processing of each flag in Y17 is performed.

FIG. 11 (P6 in FIG. 8) In P71, it is determined whether or not the accelerator is almost fully closed (for example, the opening degree is less than 5%). When the determination is YES, the traction control is determined to be unnecessary. , P76, the traction flag is reset to 0.

If the determination in P71 is NO, in P72, it is determined whether or not the traction flag is 1. YES in this determination
In other words, when traction control is in progress, P7
In 5, it is determined whether or not the accelerator opening (same meaning as the throttle opening determined by the accelerator opening) is smaller than the current motor opening (same meaning as the throttle opening determined by the position of the motor 106). Is determined. This P7
If YES in the determination of 5, the process proceeds to P76 (traction control suspension), while if NO in this determination, the control is terminated as it is.

When the determination in P72 is NO, that is, when the traction control is not currently being performed, it is determined in P73 whether the spin flag (see P27 and P33 in FIG. 9) is 1. this
If the determination in P73 is YES, the traction flag is set to 1 in P74 to execute the traction control. If the determination in P73 is NO, the control is terminated.

Thus, in the present embodiment, the traction control start condition is such that a large slip exceeding the spin determination value (WFN + 10) has occurred. The condition for stopping the traction control is when the accelerator is almost fully closed, or when the accelerator opening is reduced to a level at which the traction control becomes unnecessary (determination in P75).

FIG. 12 (P7 in FIG. 8) In FIG. 12, the estimation of the road surface μ is determined based on the vehicle body acceleration G and the vehicle speed. Then, from when the spin flag becomes 0 until a predetermined time has elapsed,
That is, for a while after the time t3 in FIG. ₃ , taking into account that the applied torque to the drive wheels is greatly reduced and sufficient vehicle acceleration cannot be obtained, the vehicle acceleration is detected at this time. I do not have it. Thus, the vehicle acceleration a while after the t ₃ is prevented from being reflected in the FTAG (see FIG. 3), a situation that would impair the sense of acceleration are avoided.

Based on the above, it is determined in P81 whether or not the spin flag is 1. If the determination in P81 is YES, after resetting the spin timer in P92, P
At 88, a predetermined conversion coefficient G is obtained by subtracting the vehicle speed WFNn-1 of the previous time (one time before the control cycle) from the current vehicle speed WFNn.
By multiplying by K, the vehicle body acceleration Gn is calculated. Thereafter, in P89, it is determined whether or not the vehicle acceleration Gn calculated in P88 is larger than the maximum value Gmax of the vehicle acceleration stored so far. If the determination in P89 is YES, the current vehicle acceleration Gn is set to the maximum acceleration G in P90.
After updating the data as max, proceed to P91, N in the judgment of P89
In the case of O, the process directly proceeds to P91 without passing through P90.

In P91, the road surface μ is estimated from the map shown in FIG. 5 based on the vehicle body acceleration Gmax and the current vehicle speed WFN. In FIG. 5, the road surface μ is classified into five stages with numerical values of 1 to 5, and the larger the numerical value, the larger the friction coefficient. (This is shown in FIGS. 6 and 7 described below. The same applies to the figure).

After P91, in P85, the data is changed with the current spin flag as the previous spin flag.

If the determination in P81 is NO, it is determined in P82 whether or not the previous spin flag was 1. This P82
If the determination is YES, the spin timer sets the predetermined value A in P83.
(For example, seconds), the previous spin flag is reset to 0 in P84, and the process in P85 is performed.

If the determination in P82 is NO, it is determined in P86 whether the count value of the spin timer has become 0 or not.
If the determination is NO, the process of P85 is performed after the countdown of the out-pin timer in P87.

If the determination in P86 is YES, it means that the time when the vehicle body does not detect the acceleration G has passed.
The following processing is performed.

FIG. 13 (P10 in FIG. 8) In FIG. 13, the position of the motor 106 is determined, that is, the throttle opening is determined. In this case, FIG.
t ₀ determines the torque rapidly decreases the amount of time and (SM setting), and the determination of the recovery opening at t ₃ time points of FIG. 3 (FIAG), t ₀
The gradual determination of the amount of torque reduction when the convergence determination value (WFN + 3) is not reached within a predetermined time from the time is performed together. In the embodiment, even when a large slip that exceeds a spin determination value occurs during the traction control, the rapid reduction of imparting torque at Figure 3 t _0, the gradual comprising imparting torque after Figure 3 T ₂ The reduction and the temporary increase of the applied torque at the time point t3 in FIG. ₃ are not performed.

Given the above, in Q1, and a road surface μ estimated and the current vehicle speed WFN, by collating the map shown in FIG. 6, the throttle limit value SM at t ₀ point is determined. The map shown in FIG. 6 is set as a minimum value required to maintain the current vehicle speed.

In Q2, the estimated road surface μ and the current vehicle speed WFN are
Compared to the map shown in the figure, the recovery opening FT at t ₃
AG is determined.

In Q3, it is determined whether or not the current flag JF (see FIGS. 9, P38 to P40) is 1. If the determination in Q3 is YES, in Q4, it is the first time that the spin determination value (WFN + 10) has been reached, that is, whether a slip larger than the spin determination value has occurred during non-traction control. Is determined. If the determination in Q4 is YES, in Q5, the target position (target opening) MTAGn of the motor 106 is changed to Q1
Is set as corresponding to the SM determined in. Then, in Q5, after updating the data of the current SM as SM1, the process proceeds to Q20.

If NO in Q3, it is determined in Q7 whether the flag JF is 2. If the determination in Q7 is YES, in Q11, it is determined whether or not it is the first time a spin determination has been made during traction control. This Q11
Is YES, the target opening MTAGn of the motor 106 is set as FTAG (see FIG. 3) in Q12, and then the process proceeds to Q20.

If the determination in Q7 is NO, it is determined in Q8 whether the time lapse flag (see P30 and P34 in FIG. 9) is 0 or not. If YES in this Q8, is when the slip value of the driven wheel from t ₀ time point of FIG. 3 to the spin convergence criterion value within the predetermined time has not been sufficiently reduced. In this case, after updating the value obtained by multiplying SM1 by a coefficient 0.9 in SM in Q9, the updated SM1 is updated in Q10.
Set as SM and move to Q5. By shifting to Q5, the slip value of the drive wheel becomes the spin convergence judgment value (WFN +
Until the pressure drops to 3), the throttle opening is gradually reduced (SM is reduced by 10% for each control cycle).

If the determination in Q8 is YES, in Q13, it is determined whether or not the split flag SPLT (see FIG. 10D, Y80, Y82, Y83) is 1. When the determination in Q13 is NO, that is, when the vehicle is not currently on the split road, the larger one of the rotational speeds WRL and WRR of the left and right drive wheels is set as the control target wheel speed SE for engine control. Also, Q1
In the case of EYS in the determination of 3, that is, when the vehicle is traveling on a split road, the smaller one of the rotation speeds WRL and WRR of the left and right drive wheels is the engine control target wheel speed SE.
Is set as As described above, when the vehicle is not on a split road, the wheel speed to be controlled is selected with emphasis on stability, whereas when the vehicle is on a split road, the wheel speed to be controlled is selected with emphasis on acceleration. Driving that makes the best use of the driving wheel grip force).

After Q14 and Q15, in Q16, after the slip addition value ΔE (3 <ΔE <10) is determined according to the road surface μ, Q17
In step (1), the target slip value SET for the engine is calculated by adding ΔE to the current vehicle speed (driven wheel speed) WFN (see FIG. 3).

After Q17, in Q18, in the PI control, the feedback control amount (throttle change amount) ΔM is adjusted so that the current rotational speed SE of the drive wheel becomes the engine target slip value SET.
Is determined. More specifically, ΔM is given by the following equation (1).
It is calculated by

ΔM = KP × (ENn−ENn−1) + KI × ENn (1) KP: proportional constant Kl: integral constant EN: SET−SE n: suffix After Q18, the previous motor target position MTAGn in QP19
By adding the change amount ΔM to −1, the current motor target position MTAGn is calculated.

After Q19 and after Q5 and Q12, the process shifts to Q20. In Q20, limit processing is performed so that the motor target position MTAGn falls within the range between the lower limit value SM and the upper limit value 100 (%).

14 (P13 in FIG. 8) In FIG. 14, the response speed for setting the motor to the predetermined target position MTAGn is set optimally, and the MTAGn is realized (output). Note that the response speed is determined by the lever 114 caused by the driving of the motor 106 (the displacement of the lever 111).
Between the lever and the lever 111, and the urging means 1
This is done in consideration of the accelerator feeling caused by the change in the 16 urging forces.

First, in Q31, the target position MTAGn of the motor is 100
(%), That is, whether the traction control is unnecessary. YES in this Q31 determination
When, in Q32, the current position (opening) of the motor 106
Is larger than a predetermined value αm (for example, 80%). If NO in the determination of Q32, in Q40, the MT
After AGn is set as it is as the last day position MTAGF,
MTAGF is output in Q39.

If the determination in Q32 is YES, in Q33, the filter time constant D is set as Dm, and then the flow shifts to Q38.

If NO in Q31, it is determined in Q34 whether the motor target position MTAGn is larger than the current accelerator opening ACP. If the determination in Q34 is YES, in Q41, it is determined whether the value obtained by subtracting the ACP from MTAGn is smaller than a predetermined value αa (for example, 5%). This Q41
If the determination is YES, the filter time constant D is
After setting as Da, move to Q38. If NO in Q41, the process shifts to Q40.

If the determination in Q34 is NO, it is determined in Q35 whether the current accelerator opening ACP is smaller than a predetermined value αc (for example, 5%). If the determination in Q35 is YES,
After the filter time constant D is set as Dc in
Move to 8. If NO in Q35, Q40
Move to.

In Q38, a final target position of the motor 106 (corresponding to a change in the motor 106, that is, a change in the throttle opening) MTAGF is determined by performing a filtering process based on the following equation (2).

MTAGF = D × MTAGn + (1−D) × MTAGn−1 (2) Of course, after Q38, MTAGF is output in Q39.

The magnitude relationship between the filter time constants is set as follows in the embodiment.

Dm <Dc <Da <1 FIG. 15 (P12 in FIG. 8) First, in Q51, the slip addition value ΔB is determined according to the road surface μ, and subsequently, in Q52, this ΔB and the vehicle speed (driven wheel speed) WFN are added. By doing so, the brake target slip value SBT is calculated (see FIG. 3). In the embodiment, the relationship is set so that ΔB> ΔE (SBT> SET) because the traction control is performed mainly by the engine as much as possible.

In Q53, the feedback control amounts TCCR and TCCL are determined by PI control so that the current slip value becomes the target slip value SBT independently for each of the left and right drive wheels 1RL and 1RR. More specifically, according to the following equations (3) and (4), TC
CR and TCCL are calculated.

TCCR = KBP × (ENRn−ENRn−1) + KBI × ENRn (3) TCCL = KBP × (ENLn−ENLn−1) + KBI × ENLn (4) ENR = WRR−SBT ENL = WRL−SBT KBP: proportionality constant KBI: integration constant n: suffix In the Q54, it is coded (converted to an integer) for output to the control unit UABS for ABS. That is, TCCR is converted to an integer as TCTR, and TCCL is converted to an integer as TCTL. After this
In Q55, the integer TCTR and TCTL are −7
The limit processing is performed so as to fall within the range of +7 to +7.

Fig. 16 (P14 in Fig. 8) The block chart in Fig. 16 corresponds to the ABS-driven type. In the case of the ABS-driven type, the control unit UA for ABS is used.
When there is a request signal from the BS, the control of FIG. 16 is performed by an interrupt process.

First, in Q61, a signal TBR is output to the ABS control unit UABS as to whether or not to request the brake control due to the traction control (when TBR = 0, it means that the brake control by the traction control is required). And TBR =
1 means no request).

In Q62, ABS sends SOT to control unit UABS.
Signals (increase and decrease in brake fluid pressure for left and right drive wheels 1RL, 1RR, and signals TCTR, TCTL of the magnitude) are output.

In Q63, it is determined based on the SIT signal from the ABS control unit UABS whether or not the ABS control is currently being performed. If the determination in Q63 is YES, the ABS flag is set to 1 to indicate that the ABS control is being performed in Q64. If NO in Q65, the ABS flag is reset to 0 in Q65.

Normally, it is unlikely that the ABS control and the traction control are required at the same time.However, for example, when driving on a rough road at a considerable speed, the drive wheel temporarily separates from the road surface and falls considerably hard on the road surface. When the vehicle falls, the vehicle may be brought into a rotational state where ABS control is required temporarily due to a braking action from a road surface.
However, how to use the determination result of a bad road or a good road utilizing such a phenomenon will not be described.

17 (P15 in FIG. 8) In Q71, it is determined whether or not the traction control is currently being performed. If the determination in Q71 is YES, in Q72, a signal to the effect that the traction control shift characteristic shown in FIG. 4B should be selected is output to the shift control unit UAT. Thereafter, in Q73, the flag TE is set to 1 which indicates that the traction control shift characteristic has been selected as the shift characteristic.

If NO in Q71, the flag TE is set to 1 in Q74.
Is determined. If the determination in Q74 is NO, in Q76, the control unit FAT for shifting
After waiting for a command to select the shift characteristic for normal running shown in FIG. 4A, the flag TE is reset to 0 in Q77.

If the determination in Q74 is YES, in Q75, it is determined whether or not the accelerator opening is zero. NO in this Q75 determination
If so, the flow shifts to Q72, and if the determination in Q75 is YES, the flow shifts to Q76.

As described above, in the embodiment, once the traction control shift characteristic is selected, the condition is returned to the normal traveling shift characteristic on condition that the accelerator is fully closed. By doing so, excessive re-generation of slip due to a change in the shift characteristic is prevented.

Relationship between UTR and UABS The control unit UTR for traction control and the control unit UABS for ABS control are both configured using a microcomputer, but signals transmitted and received between the two control units will be described.

First, from the UTR, a signal indicating the presence or absence of a traction control request is a TBR signal as described above (when 1 indicates that there is no traction control, when 0 indicates that there is traction control). Shown).

Each of the control units UTR and UABS has communication modules MT and MA for serial transmission (see FIG. 1), and an 8-bit signal is transmitted and received by time division transmission using these modules.

The signal SOT transmitted from the UTR is shown in FIG. The signal SOT has eight bits b to i, where each bit has the following meaning. First, bits be are:
For the left rear wheel 1RL, the control time of the brake fluid pressure is indicated by bits b to d, and specifically, the ON time of the solenoid valve of the fluid pressure adjusting unit 24 is indicated as a numerical value of 0 to 7 (FIG. 15). Q55). The bit e indicates whether the pressure is increased or decreased (the difference between + and-). Bits f to i are for the right rear wheel 1RR. Bits f to h indicate the control time of the brake fluid pressure, and bit i indicates the distinction between pressure increase and pressure reduction.

The signal SIT transmitted from UABS is shown in FIG.
The signal SIT has eight bits b to i, but practically only four bits d, e, h, and i are used. The bit h is an echo back of the traction control data reception confirmation, where h = 0 indicates a match or the signal TBR is 1 (high), and h = 1 indicates a mismatch. The inverted signal of the bit h is the bit d. Bit i indicates the ABS control state. I = 0 indicates that the ABS is not being controlled, and i = 1 indicates that the ABS is being controlled. The bit e indicates an inverted signal of the bit i.

The traction control data is always transmitted from the UTR to the UABS, and when the traction control is requested, the UABS controls the brake fluid pressure in preference to the ABS control (UTR initiative). On the other hand, only when there is a request signal from UABS (for example, when ABS is not controlled,
A request signal is output in synchronization with the output timing of the brake fluid pressure adjustment signal), and traction control data transmission can be performed (led by UABS).

Details of the ABS Control The ABS control, as is known, prevents the wheels from locking to the road surface due to excessive braking. In this embodiment, the lock state of each wheel with respect to the road surface is indicated by a lock value defined by the following equation (5).

Lock value (S1) = (vehicle speed−wheel speed) / vehicle speed (5) As is apparent from the above equation (5), the larger the lock value S1, the greater the tendency that the wheels are locked. means. And, generally, this lock value S1 is 0.1
The brake force (brake fluid pressure adjusting unit 24) for each wheel is feedback-controlled (for example, PI control) so that the target value is set in a range of 0.2. In this case, the target value can be changed according to the road surface μ (for example, the target value is set to 0.1 on a snowy road, and set to 0.2 on a pavement road).
To).

As a condition for starting the ABS control, in the embodiment, the lock value S1
Is larger than a predetermined start determination value R1 (R1> R2). Further, as a condition for stopping the ABS control, in the embodiment, the lock value S1 is a predetermined end determination value R2.
It is set as when it is smaller than (0 <R2 <0.1).

Next, an example of the ABS control will be described with reference to FIG. 20, taking the case of the traction control initiative as an example.
In the following description, X indicates a step.

First, after each wheel speed is read in X1, each wheel speed is output to the control unit UTR for traction control in X2 (for example, included in the SIT signal).

In X3, it is determined whether or not the flag TBR is 0. When the determination of X3 is YES, that is, when brake control for traction control is required,
At X4, signals TCTR and TCTL indicating the brake control amount from the control unit UTR are read (see the description of FIG. 8). Then, at X5, the brake control read at X4 is output to the brake fluid pressure adjustment unit 234.

On the other hand, when NO is determined in the determination of X3, that is, when the brake control for traction control is not necessary, the estimation of the vehicle speed is estimated in X6 in the same manner as described in, for example, the traction control section, and then in X7. The lock value S1 is calculated based on the equation (5).

After X7, it is determined in X8 whether the lock flag is 1 or not. When the lock flag is 1, it indicates that the ABS control is being performed. If the determination in X8 is NO, that is, if the ABS control is not currently being performed, it is determined in X9 whether the current lock value S1 is greater than the ABS control start determination value R1. If the determination in X9 is YES, the lock flag is set to 1 in X10, then the brake control amount is determined in X11 by, for example, PI control, and in X12, the brake control amount is
Output to 24.

If the determination in X8 is YES, it is determined in X13 whether the current lock value S1 is smaller than the ABS control end determination value R2. If the determination in X13 is NO, the process shifts to X11 and brake control by ABS control is continued. If the determination in X13 is YES, the lock flag is reset to 0 in X14.

After the above X5, X12, X14, or when the determination of X9 is NO, the process proceeds to X15, and the SIT signal is output to the traction control control unit UTR (see the description of FIG. 19). .

[Brief description of the drawings]

FIG. 1 is an overall system diagram showing one embodiment of the present invention. 2 (a) to 2 (d) are schematic diagrams showing different operation states of the throttle opening adjustment mechanism. FIG. 3 is a diagram schematically showing the contents of traction control. FIG. 4A is a diagram showing an example of shift characteristics used during normal running. FIG. 4B is a diagram showing an example of shift characteristics used during traction control. 5 to 7 are views showing maps used for control of the present invention. 8 to 17 and 20 are flowcharts showing control examples of the present invention. FIG. 18 and FIG. 19 are diagrams showing signals transmitted and received between a control unit for traction control and a control unit for ABS control. FIG. 21 is a time chart showing the relationship between a flag and a timer used for split road determination. 1: Engine 63-66: Sensor (wheel speed) UTR: Control unit (for traction control) UABS: Control unit (for ABS control) UAT: Control unit (for shift control)

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16H 59/66 F16H 59/66 G01N 19/02 G01N 19/02 B // F16H 59:36 (72) Inventor Hiroshi Tsukahara Hiroshima No.3-1 Shinchi, Fuchu-cho, Aki-gun Mazda Co., Ltd. (56) References JP-A-2-220958 (JP, A) JP-A-1-197158 (JP, A) JP-A-1-182154 (JP, A) JP-A-1-204854 (JP, A) JP-A-2-77351 (JP, A) JP-A-2-1022861 (JP, A) JP-A-1-257654 (JP, A) JP-A-64 -44371 (JP, A) JP-A-60-22548 (JP, A) JP-A-60-255560 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60T 8/34- 8/58 B60T 8/24 B60T 8/00

Claims (1)

(57) [Claims] 1. A left rotation detection means for detecting a rotation speed of a left drive wheel, a right rotation detection means for detecting a rotation speed of a right drive wheel, Within a predetermined time from the point of occurrence of the spin at which the rotation speed becomes larger than the rotation speed of the other drive wheel by a predetermined value or more, the spin is generated again on the one drive wheel, and the other drive wheel is rotated within the predetermined time. A determination unit that determines that the vehicle is on a split road on condition that the rotation speed does not increase by a predetermined value or more.