JPH0343635A - Traction controller - Google Patents

Abstract

PURPOSE:To securely prevent the generation or repetition of slipping by closing a throttle valve at a predetermined speed to a compensation throttle opening at the time of slipping of a wheel, and by opening the throttle valve gradually according to the compensation throttle opening speed at the time of gripping of the wheel. CONSTITUTION:A control unit 30 inputs various signals from sensors 20-24 that detect driving conditions of an automobile, especially, after judging slipping or gripping condition of a wheel based on the relation to a wheel speed and a car speed, it controls opening and closing of a throttle valve 13 of an engine 1 through a motor 14. At the time of slipping of the wheel, a compensation throttle opening is set in relation to the car speed by a means 36, and the throttle valve 13 is closed at a predetermined speed to the compensation throttle opening. At the time of gripping of the wheel, the compensation throttle opening speed is set in relation to a road surface frictional coefficient by a means 37, and the throttle valve 13 is gradually opened according to the compensation throttle opening speed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a traction control device that prevents slippage and optimally accelerates by controlling driving force when wheel slip occurs during rapid acceleration of a vehicle. , relates to throttle valve closing control when slipping and throttle valve opening control when gripping.

[Conventional technology]

Generally, in a vehicle, wheel slip may occur during sudden acceleration due to an increase in engine output, etc. When such wheel slip occurs, slip is prevented by closing a throttle valve and controlling engine output. So-called traction control has been proposed. In this traction control, it is important to determine whether the vehicle is slipping or gripping, how to control the resistance of the throttle valve during slipping, and how to control the opening of the throttle valve during gripping.

Conventionally, regarding the above-mentioned traction control, there is a prior art disclosed in, for example, Japanese Unexamined Patent Publication No. 182434/1983. Here, a reference speed is determined based on the driven wheel speed, and slip is determined based on the relationship between this reference speed and the driving wheel speed.

Further, it is shown that a corrected speed is calculated based on the acceleration of the driving and driven wheels and the driving wheel speed, and in the event of a slip, the throttle valve is opened and closed at a speed proportional to the difference between the reference speed and the corrected speed.

[Problem to be solved by the invention]

By the way, in the prior art described above, slip is determined based on the relationship between the reference speed based on the driven wheel speed and the driving wheel speed, so it cannot be applied to four-wheel drive vehicles. Furthermore, since the reference speed is set regardless of road surface conditions, it is not possible to appropriately determine slips and the like on low-friction roads (low-μ roads) and high-friction roads (high-μ roads). Furthermore, since the throttle valve is opened and closed at a speed proportional to the difference between the reference speed and the corrected speed, the responsiveness of the throttle valve closing control during slipping deteriorates. Furthermore, since the road surface condition is not judged, slips occur repeatedly on low-μ roads, and it takes time to completely resolve them.

On the other hand, on roads other than high friction roads and low vehicle speeds, there are problems such as negative acceleration caused by sudden grip.

The present invention has been made in view of the above, and its purpose is to provide traction that can appropriately determine slippage, etc. according to road surface conditions and improve the responsiveness of slip prevention control. The purpose is to provide a control device.

[Means to solve the problem]

In order to achieve the above object, the traction control device of the present invention provides a correction throttle opening degree setting for slippage in a control system that controls a throttle valve by determining wheel slip and wheel grip based on the relationship between wheel speed and vehicle body speed. means for determining the corrected throttle opening in relation to at least the vehicle body speed, controlling the throttle valve to close at a predetermined speed up to the corrected throttle opening when slipping, and setting means for setting corrected throttle opening speed for gripping. The corrected throttle opening speed is determined in relation to the road surface friction coefficient, and the throttle valve is controlled to gradually open according to the corrected throttle opening speed during gripping.

[For production]

Based on the above configuration, when the wheel speed during sudden acceleration becomes higher than the vehicle speed by more than a set value and a slip is determined, the throttle valve is immediately controlled to close until the throttle opening is corrected according to the vehicle speed at this time, and the driving situation etc. Reliably prevents slipping. When it is determined that grip is present due to a decrease in wheel speed, the throttle valve is controlled to open gradually using the corrected throttle opening speed based on the road surface friction coefficient μ at this time, and returns to normal even on low μ roads while preventing slippage from occurring again. .

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, in the case of a four-wheel drive vehicle with a center differential, reference numeral i is an engine, and this engine l is configured to be transmitted to a center differential device 3 via a transmission 2. The front drive shaft 4 from the center differential device 3 is connected to the front differential device 5. The left and right front wheels 7L are connected via the axle 6.

7R, and the rear drive shaft 8 is connected to a rear differential device IO via a propeller shaft 9 and the like, and further connected to left and right rear wheels 12L and 12R via an axle 11. A motor L4 is connected to a throttle valve L3 of the engine L, and the throttle valve 13 is electrically opened and closed in response to operation of an accelerator pedal (not shown).

Next, regarding the electric control system, the throttle valve 1
Throttle opening sensor 20° attached to 3. Accelerator opening sensor 21 attached to the accelerator pedal. Each wheel speed sensor 22L, 22R, 23L is attached to the left and right front wheels 7L, 7R and the left and right rear wheels 12L, 12R.
and acceleration sensor 24 installed on the 23R1 vehicle body side
These sensor signals are input to the control unit 30.

The control unit 30 includes driving wheel wheel speed calculation means 31 , vehicle body speed calculation means 32 . It has road surface μ detection means 33.

The driving wheel speed calculation means 3i includes four wheel speed sensors 22L, 22R, 23L, and 23R.
pt, +U FRI U RLI U RR is input,
From these, the wheel speed U is calculated as follows.

U = f(U RLI U PR, U RL, U
RR) Here, in order to make it easier to detect slip, the function r takes the larger value of left and right front wheel speed 2jpt+UpR, takes the larger value of left and right rear wheel speed URLr UR*, and calculates the average value of both. seek. That is, U pt >
If V FRIU+u, > U**, then U − (U
RLI U IIt) /2, and thus it is determined to be thick.

The vehicle speed calculating means 32 manually inputs the above-mentioned front left wheel speed UpL + front right wheel speed Up* + rear left wheel speed UllL, right rear wheel speed U□ and the vehicle body acceleration G of the vehicle body acceleration sensor 24, and calculates the vehicle body speed V. Calculate as follows.

V=g(G, Upt,, UpR,17*t,
(MRR) Here, in order to make it easier to detect slip, the wheel speed U is set to be large as described above, and the vehicle body speed V
needs to be set small. Therefore, the function g is determined by selecting the smallest value among the integral value fGdt of the acceleration G and each wheel speed of the four wheels. That is, URR>Upt (-U
pII) > URL > f Gdt, V-J
“Gdt.

The road surface μ detection means 33 detects the road surface friction coefficient μ, and if the value of the road surface friction coefficient μ is low at the time of slipping and slipping is likely to occur, the value of the vehicle body acceleration G is also small. When the value of the road surface friction coefficient μ is high and the road surface is close to a dry road surface, slips are less likely to occur and the value of the vehicle body acceleration G becomes large, and thus the road surface friction coefficient μ becomes proportional to the vehicle body acceleration G. Therefore, the road surface friction coefficient μ is manually set in the road surface μ detection means 33 using the vehicle body acceleration G as μ−kG (k is a constant).

The above-mentioned wheel speed U and vehicle body speed V are determined by the slip determination means 34.
and the grip determination means 35, and the difference between the two ■
and the set value vA. If UV>VA, it is determined that there is a slip, and a slip signal is manually input to the correction throttle opening setting means 36. On the other hand, if U-v≦vA, it is determined that there is a grip, and a grip signal is input to the correction throttle opening speed setting means 37.

The corrected throttle opening setting means 36 controls the throttle valve 13 to close immediately at the time of slip, and closes the throttle valve 13 to a maximum value of 6M and a corrected throttle opening θ corresponding to the slip state. Here, if the corrected throttle opening θ5 is uniformly set to a predetermined value, the vehicle body will generate negative acceleration when the vehicle speed V is high, and the responsiveness to the grip will deteriorate when the vehicle speed V is low. Therefore, the corrected throttle opening θ5 is set proportionally to the vehicle speed V as shown in FIG. 2(a), and this map is searched based on the vehicle speed V to set the corrected throttle opening θS. .

The corrected throttle opening speed setting means 37 controls the opening of the throttle valve (3) to return to its original state when gripping after slipping, and is given a predetermined corrected throttle opening speed 6. 65. During this grip, it is desired to return quickly while preventing repeated slipping, and in this respect the road friction coefficient μ has a large influence. In other words, the lower the road friction coefficient μ, the more likely the slip will be. To avoid this, it is necessary to set the corrected throttle closing speed 6. to a small value.As a result, as shown in Fig. 2 (b), the corrected throttle opening speed 6.sup. Therefore, this map is searched using the road surface friction coefficient μ to determine the corrected throttle opening speed δS.

These throttle closing speed e y + corrected throttle opening degree θ5. Corrected throttle opening speed6. is input to the throttle drive means 38, and a throttle control signal corresponding thereto is output to the motor 14.

On the other hand, the throttle opening θ of the throttle opening sensor 20 is input to the actual throttle opening detection means 89 to detect the actual throttle opening θ. Further, the accelerator opening degree φ of the accelerator opening degree sensor 21 is manually determined by the target throttle opening setting means 40 to set the target throttle opening degree θ according to the accelerator opening degree φ.
. Establish. During normal driving without slippage, the target throttle opening is θ. and actual throttle opening θ
, is manually applied to the throttle drive means 38 to convert the actual throttle opening θ to the target throttle opening θ. The motor 14 is driven by feedback control so as to follow.

Furthermore, the above-mentioned slip and grip judgment signals, actual throttle opening θ1. It has a control mode determining means 41 to which the target throttle opening degree θ0 is input, determines each mode of slip, grip after slip, and normal driving, and inputs this mode signal to the driving means 38. Then, it outputs a throttle control signal according to each mode, especially when gripping after slipping, θ, ≧θ. When it does, it switches to normal mode.

Next, the operation of the traction control device having such a configuration is as follows.
This will be described using the flowchart in FIG. 3 and the timing chart in FIG.

First, by depressing the accelerator pedal at the time of starting, etc., power from the engine 1 is transmitted to the front wheels 7L, 7R and the rear wheels 12L, 12R via the transmission 2° center differential device 3, etc. So the front wheel 7L,
The vehicle travels by rotation of 7R and rear wheels 12L and L2R.

At this time, the flowchart in FIG. 3 is executed, and step 510 (each wheel speed U PLI U PRI 1) is executed.
The RLI '11 RR is read, and in step 5102, the wheel speed U is calculated from the larger average value of the front and rear wheel speeds. Further, in step 5toa, the vehicle body acceleration G detected by the acceleration sensor 24 is read, and in step 5104, the vehicle body speed
pt.

It is calculated using the minimum value of U PRI 27 RLI PRI, and in this way, slip can be detected with high accuracy based on the relationship between wheel speed U and vehicle body speed V.

Also, the actual throttle opening θ2. detected by the throttle opening sensor 20 in step 3105. Accelerator opening φ
Target throttle opening θ according to. is set.

Therefore, in step 3106, it is determined whether there is a slip based on the difference between the wheel speed U and the vehicle body speed V and the set value VA.If the slip is non-slip, the traction control flag F is checked in step 5107, and if it is cleared, the traction control flag F is checked. Judged as normal mode. Then, in step 5 (08), the throttle closing speed 6 is set to the maximum IiiθM, and after clearing the flag F in step 5109, the throttle is controlled so that the actual throttle opening θ follows the target throttle opening θ.

Therefore, the motor 14 operates at a target throttle opening θ corresponding to the accelerator opening φ.

The throttle valve t3 is electrically opened and closed.

On the other hand, when starting suddenly on a low-μ road as shown in Fig. 4, the wheel speed U suddenly increases relative to the vehicle speed V and reaches 2z-v at time t1.
When it reaches av^, it is determined to be a slip and the process proceeds to step 910.
6 to step 8110. Then, a corrected throttle opening θ is set according to the vehicle speed V, and step 5it
At step t, the throttle closing speed 6 is set to the maximum value 6M according to the corrected throttle opening degree θS, and at step 5IL2, the traction control flag F is set. Therefore, at time t1, the throttle valve 13 is immediately controlled to close to the corrected throttle opening θ5 to prevent slippage, as shown in FIG. θ5 is set small to reliably prevent slipping.

Due to the closing control of the throttle valve 13, the wheel speed U decreases, and when y-v<v^ at time t2, the grip and 111
Cut off. Therefore, from step 5ioe to step 31
07, proceed to step 5 (proceed to step 13, and then step 31)
14, the road surface friction coefficient μ is set by the vehicle body acceleration G,
In step 5l15, the throttle opening speed is corrected according to the road surface friction coefficient μ. is calculated, and in step 911B, this corrected throttle opening speed 4s is stored as throttle closing speed 6, and the throttle is controlled accordingly. Then time t
From 2 onwards, the throttle valve 13 gradually opens and returns from the corrected throttle opening degree θ to the corrected throttle opening speed d, so that the wheel speed U is prevented from returning suddenly and slipping again. , increases substantially along with the increase in vehicle speed V. Here, the corrected throttle opening speed ds is set in relation to the road surface friction coefficient μ, so if the increase in vehicle body speed V is small on a low μ road and slipping is easy, the increase in wheel speed U is also small, and on a high μ road When the increase in vehicle speed V is large, the wheel speed U also increases greatly.

When θ becomes ≧θ0, the process proceeds from step 5113 to step 3108 and returns to the normal mode.

Referring to FIG. 5, another embodiment of the present invention will be described.

This is to set the corrected throttle opening θS using a two-dimensional map of vehicle speed V and vehicle acceleration G, which is expressed as the following equation.

θ5− K o + K 1 ・G + K 2 ・V
(Ko, 1. and 2 are constants) Therefore, according to this map, even if the vehicle speed V is high, if the value of the vehicle acceleration G is small on a low μ road, the corrected throttle opening θ is a relatively small value. This increases the anti-slip effect.

Although the embodiments of the present invention have been described above, they can be similarly applied to two-wheel drive vehicles.

〔Effect of the invention〕

As described above, according to the present invention, in vehicle traction control, the throttle valve is immediately closed when slipping, and the throttle valve is slowly opened when gripping, so that the responsiveness and reliability of slip prevention are improved. It has good properties and can reliably prevent slipping from occurring again when gripping.

Furthermore, in the event of a slip, the corrected throttle opening amount is set based on the vehicle speed or the vehicle acceleration in combination with the vehicle speed, so that slip prevention can be ensured depending on the driving conditions and the road surface friction coefficient.

Furthermore, during gripping, the corrected throttle opening speed based on the road surface friction coefficient can appropriately prevent slip recurrence depending on the road surface condition.

Further, slip and grip can be determined with high accuracy based on the relationship between wheel speed and vehicle body speed taking into account vehicle body acceleration, and can be applied to four-wheel drive vehicles.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing an embodiment of the traction control device of the present invention, Figures 2 (a) and (b) are diagrams showing a map of corrected throttle opening and corrected throttle opening speed, and Figure 3 is a traction control system. FIG. 4 is a characteristic diagram showing the relationship between throttle opening change during slip, wheel speed, and vehicle body speed. FIG. 5 is a diagram showing another map of corrected throttle opening. l...engine, 13...throttle valve, L4...
- Motor, 30... Control unit, 34... Slip determining means, 35... Grip determining means, 36...
Correction throttle opening setting means, 37... Correction throttle opening speed setting means, 38... Throttle driving means

Claims (3)

[Claims] (1) In a control system that controls a throttle valve by determining wheel slip and wheel grip based on the relationship between wheel speed and vehicle body speed, the control system has a correction throttle opening setting means for slippage, and at least the relationship with the vehicle body speed. determines the corrected throttle opening, and controls the throttle valve to close at a predetermined speed up to the corrected throttle opening when slipping, and has a corrected throttle opening speed setting means for gripping, and corrects it in relation to the road surface friction coefficient. A traction control device characterized in that a throttle opening speed is determined and the throttle valve is controlled to gradually open according to the corrected throttle opening speed during gripping. (2) The traction control device according to claim 1, wherein the corrected throttle opening degree and the corrected throttle opening speed are both set as increasing functions with respect to vehicle speed and road surface friction. (3) The traction control device according to claim (1), wherein the corrected throttle opening is set according to vehicle speed and vehicle acceleration.