JPH0816457B2 - Automotive skid control - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skid control device for an automobile, which performs skid control for controlling a driving force according to a slip state of driving wheels.

(Prior Art) Conventionally, as a skid control (or a traction control) for controlling a rotation speed of a driving wheel of an automobile, there has been disclosed in
As seen in No. 59-202963, when the rotation difference between the driving wheel and the driven wheel exceeds the set value and a slip occurs, the torque transmitted to the driving wheel is reduced by controlling the clutch or the accelerator. Techniques for removing slips are known.

In the skid control as described above, the driving force can be separated from the accelerator operation by the driver according to the driving state of the vehicle, and the optimum driving state can be controlled according to the accelerator operation amount. In particular, when the engine driving force is large and a slip occurs in a slippery road surface state, the driving force is reduced to suppress the slip. However, in the skid control, the situation in which the occurrence of slip exceeds the allowable value changes depending on the road surface condition and the driving condition. On the other hand, when a slip occurs again, even if the road surface condition is the same, control is performed to find the optimum value of skid control to suppress this slip, and it takes time to reach the optimum condition and the response It becomes an obstacle when trying to improve sex.

In other words, slip is likely to occur when the engine is operated in the fully open state, and when the slip begins to occur, the slip rate increases rapidly, so with the occurrence of slip, a predetermined reduction rate occurs. Reduce the driving force,
If skid control is performed to determine whether the slip is decreasing in the reduced state and the driving force is further reduced, the degree of change in the driving force is small and a large slip occurs when the skid control is started. Become. on the other hand,
Increasing the degree of change in the driving force improves the convergence when a slip occurs, but reduces the control stability of the driving force in the optimum slip state.

In addition, since the road surface condition is reflected in the slip condition of the driving wheels, the skid control that detects this slip condition and controls the driving force according to the slip condition also affects the control amount at the initial stage of slip occurrence. Although the road surface condition is reflected, it is reflected as a result of control, and even if the road surface condition is the same, if a slip occurs when the vehicle starts again after stopping once, the same as the previous time The skid control is repeated, and the responsiveness of the control does not change at all. That is, the slip state is detected from the rotational speed difference between the driving wheel and the driven wheel, and the skid control according to the slip state is a feedback control of the driving force of the engine so that the slip becomes a predetermined state. And
It can be estimated from the control result that the road surface is slippery if the slip is large with the same driving force, and thus the road surface state cannot be detected unless the relationship between the slip and the driving force is obtained.

On the other hand, although it is considered that good control can be performed by detecting the road surface condition and reflecting it on the skid control, providing a special sensor for detecting the road surface condition is disadvantageous in terms of cost, and the drive wheel is There is also known a technique of determining the road surface state based on the slip state at the time of slip and performing skid control based on the determination result (see Japanese Patent Laid-Open No. 60-197434), but before entering skid control. Since the road condition is judged, the time required for the judgment,
There is a problem that the control start is delayed and the optimum skid control cannot be performed.

(Object of the Invention) In view of the above circumstances, it is an object of the present invention to provide a skid control device for an automobile, which improves responsiveness in the early stage of slip occurrence in skid control according to slip occurrence. It is a thing.

(Structure of the Invention) The skid control device of the present invention detects the rotation speed of the drive wheel and the rotation speed of the driven wheel, and slips when the rotation speed of the drive wheel is a predetermined value or more than the rotation speed of the driven wheel. Based on the set control amount, and a slip detection unit that determines that the slip is generated, a control amount setting unit that sets a control amount that controls the driving force when the slip detection unit determines that a slip has occurred. A road surface state determination is provided, which has a skid control means configured by a drive force control means for controlling the drive force, and determines the degree of slipperiness of the road surface based on the drive force control amount during the control by the skid control means. Means and a road surface state storage means for storing information on the road surface friction state determined by the road surface state determination means, wherein the control amount setting means is the road surface state in the previous control. It is characterized in that the control amount at the initial stage of slip generation is set on the basis of the information on the road surface friction state stored in the storage means.

FIG. 1 is an overall configuration diagram for clearly showing the configuration of the present invention. For the automobile 1, the driving wheels 2,3 are calculated based on the rotational speed difference between the driving wheels 2,3 and the driven wheels 4,5 or the rotational acceleration of the driving wheels 2,3.
Slip detection means 7 for detecting the slip state of
When the rotational speeds of the drive wheels 2 and 3 become higher than the rotational speeds of the driven wheels 4 and 5 by a predetermined value or more, the slip detecting means 7
Judge as slipping. This slip detection means 7
The control amount setting means 8 having received the signal of No. 2 sets the control amount for controlling the driving force when it is determined that the slip has occurred, and the signal of the control amount setting means 8 is the driving force control means 9 Is to be transmitted to the slip detecting means 7, the control amount setting means 8 and the driving force control means 9 by adjusting the throttle opening degree of the engine 6 based on the set control amount. Thus, the skid control means 10 is configured to control the driving force so that the slip is in the optimum state when the slip occurs.

Then, during the skid control by the skid control means 10, a road surface state determination means 11 for determining the degree of slipperiness of the road surface based on the driving force control amount by the control amount setting means 8 is provided. The signal of 11 is a road surface state storage means for storing information on the determined road surface friction state.
Output to 12. The control amount setting means 11 sets the control amount at the initial stage of slip generation according to the degree of slipperiness of the road surface, based on the information on the road surface friction state at the time of the previous control stored by the road surface state storage means 12. This is output to the driving force control means 9 and reflected in the skid control.

According to the present invention, during skid control by the skid control means, the road surface state, that is, the degree of slipperiness of the road surface is determined and stored based on the control amount, and this memory is stored when the next slip occurs. It is possible to set the control amount for skid control to the optimum value according to the previous road surface friction state, and immediately set the control amount for skid control at the initial stage of slip occurrence to achieve the optimum state. It is possible to perform control in the vicinity in a short time and have excellent responsiveness. From this state, skid control can be performed according to the state of slip occurrence, and the occurrence of slip can be suppressed early and a larger driving force can be obtained.

(Examples) Examples of the present invention will be described below with reference to the drawings. Second
The figure is an overall configuration diagram of a specific example.

The automobile 1 is provided with left and right driving wheels 2 and 3 and driven wheels 4 and 5, and the driving force of the engine 6 is applied to the driving wheels 2 and 3 by the propeller shaft 15.
And transmitted via the drive shaft 16.

The driving force of the engine 6 is controlled by the operation of the throttle motor 18 that adjusts the opening of the throttle valve 17. The throttle motor 18 has a control unit
A control signal from 20 is output to control its operation, that is, the engine output.

The control unit 20 is installed on the right and left drive wheels 2 and 3 and the driven wheels 4 and 5 in order to detect the slip state of the drive wheels 2 and 3, and detects the rotational speed of each wheel 2 to 5. Rotation speed signals Vr, Vl, Vo from speed sensors 21 to 24
r and Vol are input respectively. Further, in order to detect the operating state of the engine 6, the throttle opening signal T from the throttle sensor 25 for detecting the opening of the throttle valve 17 is detected.
A, an engine speed signal Ne from a speed sensor 26 that detects an engine speed, a gear position signal GP from a gear position sensor 27 that detects a gear shift position of a transmission, an accelerator sensor that detects an operation amount of an accelerator pedal 28 The accelerator signal Aa from 29 is input to the control unit 20, respectively.

The control unit 20 has the functions of the respective means shown in FIG. 1 and calculates the right / left average speeds of the driving wheels 2 and 3 and the right / left average speeds of the driven wheels 4 and 5 to determine the slip ratio based on the difference between the two. Then, a control signal is output to the throttle motor 18 of the engine 6 so that the slip ratio becomes optimum, and the driving force is skid controlled. On the other hand, the degree of slipperiness of the road surface is determined from the relationship between the average throttle opening degree and the engine speed in the skid control, and the control map of the initially set throttle opening degree according to the degree of slipperiness is selected. Next, when slip occurs and skid control of the throttle opening is performed, the initial throttle opening is obtained from the control map selected according to the road surface condition in correspondence with the engine speed and the gear position. The opening is controlled and the skid control is started according to the slip state at the throttle opening.

The basic operation of the control unit 20 will be described based on the flowchart of FIG. After the start, the output signals of the various sensors are read in step S1.
Then, an average speed V of the right and left driving wheels 2 and 3 at the step S2, similarly determine the average velocity V ₀ which right and left driven wheels 4,5 in step S3, based on the difference V-V ₀ which both average speed step The slip ratio S of the drive wheels 2 and 3 is calculated in S4.

In step S5, it is determined whether or not the slip ratio S exceeds a set value Sst (reference slip ratio for starting control). The region of the slip ratio S equal to or less than the set value Sst is a region where the driving force W and the slip ratio S are low and skid control is not performed, as shown in the relationship between the slip ratio S and the driving force W in FIG. Therefore, when the determination in step S5 is NO, the throttle opening TA is set as a function of the accelerator operation amount Aa only in step S12, and the throttle motor 18 is controlled to control the throttle valve 17 at this throttle opening TA. It outputs a control signal (step S14).

On the other hand, if the determination in step S5 is YES and the slip ratio S exceeds the set value Sst, it is determined in step S6 whether or not the previous slip ratio S'is less than or equal to the set value Sst. Starts with YES and the slip ratio S is the set value S
When st is exceeded, the throttle opening TA is set to the initial set value TA ₀ in step S7, and then the process proceeds to step S8.

Step S8 is to determine whether the slip ratio S is equal to or less than the target value S ₀ . As shown in FIG. 5, the target value S ₀ is in the optimum state in which the driving force W is maximized. At the slip ratio S equal to or less than the target value S ₀ , the engine output is increased and the optimum driving force is increased. The target slip state is obtained. On the other hand, when the slip ratio S exceeds the target value S ₀ , the slip ratio S becomes large even if the engine output is increased, and the drive wheels 2 and 3 become idling. The target slip ratio S ₀ is controlled to obtain the optimum driving force.

Therefore, when the determination in step S8 is YES and the slip ratio S is equal to or less than the target value S ₀ , the throttle opening TA is increased by the predetermined value ΔTA in step S9 to increase the engine output. On the other hand, the determination in step S8 is NO.
In the slip area exceeding the target value S ₀ , step S11
In order to reduce the engine output by decreasing the throttle opening TA by a predetermined value ΔTA, the throttle opening TA is set to a value larger than the lower limit TAmin in step S10 so as not to drop below the lower limit TAmin. It is determined whether or not A control signal corresponding to the throttle opening TA corrected and set as described above is supplied to the throttle motor 18 in step S14.
Is output to control the engine output, and the skid control is performed by feedback control so that the slip state associated therewith becomes the optimum state.

Next, in step S13, regarding the skid control so that the slip ratio S becomes the target value S ₀ as described above, the throttle opening TA as the control amount is learned and the initial set value set in step S7 is set. TA ₀ is calculated according to the road surface condition.

Details of the processing contents of step S13 are shown in the subroutine of FIG. First, in step S15, the average value TAa of the throttle opening TA in the skid control is calculated.
At this average throttle opening TAa, the slip ratio S is the target value S
It is a throttle opening required to control to _0, and when the skid control is restarted after the skid control is stopped due to the stop of the vehicle or the like on the same road surface state, the slip ratio S exceeds the set value Sst. The throttle opening is reproduced when the skid control is performed to the target value S ₀ .

Then, in step S16, it is determined whether or not the calculation of the average throttle opening TAa is completed, and if completed, the road surface is calculated from the relationship between the average throttle opening TAa and the engine speed Ne in steps S17 and S18. Determine the state. That is, as shown in the determination table of FIG. 6, the smaller the average throttle opening TAa with respect to the engine speed Ne, the more slippery the road surface condition is. The road surface condition is determined by dividing the areas into areas with area division numbers I = 1, 2, and 3 in order of increasing ease.

A step S17 decides whether or not the average throttle opening TAa is larger than the boundary line A dividing the region I = 3, and a step S18 judges that the average throttle opening TAa is smaller than the boundary line B dividing the region I = 1. It is determined whether or not it is large. When the determination in step S17 is NO, the slipperiness is greatest, and the region I is set to 3 in step S21. When the determination in step S18 is YES, the slipperiness is high. In step S19, the area I is set to 1 in a small state, and the determination in step S18 is
If NO, the region I = 2 is set in step S20.

Then, after determining the road surface condition as described above, the initial setting value TA ₀ of the throttle opening is obtained from the map corresponding to the region I in step S22. As shown in FIG. 7, this map shows that the initial setting value TA ₀ of the throttle opening is set based on the relationship between the engine speed Ne and the gear position GP, and this map corresponds to the road surface condition. Region I = 1,2,
It is formed every three. In the map of the region I = 3 with respect to the map of the region I = 1, the initial set value TA ₀ is set to a small value even if the engine speed Ne and the gear position GP are the same. The above result is stored in the memory, and in the setting of step S7, the optimum initial set value TA ₀ is set according to the operating state at that time.

According to the above-described embodiment, in the skid control in which the throttle opening TA is adjusted and the slip ratio S is feedback-controlled toward the target slip ratio S ₀ , the control amount, that is, the throttle opening TA is the road surface under the operating condition. The throttle opening TA is compared with a reference value corresponding to the engine speed Ne at each gear shift position GP to determine the road surface condition, and the result is stored in a memory. Remember. Next, when the skid control is once stopped due to the shift to light load operation, and the accelerator operation amount increases again and the slip ratio S exceeds the set value Sst, it is selected according to the road surface condition. Set the throttle opening to the initial setting value TA ₀ read from the map,
The skid control from the throttle opening to the target slip ratio S ₀ is started.

The road surface condition classification in the table of FIG. 6 in the above embodiment may be further subdivided. Further, the control of the driving force may be performed by controlling various engine output adjusting means in addition to the throttle opening adjustment.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram for clarifying the configuration of the present invention, FIG. 2 is an overall configuration diagram of a specific example, FIG. 3 is a basic flowchart diagram for explaining the operation of a control unit, and FIG. 4 is a road surface. FIG. 5 is a flowchart showing a subroutine for determining the condition, FIG. 5 is a characteristic diagram showing the relationship between the slip ratio and the driving force, FIG. 6 is a characteristic diagram showing a table for road condition determination, and FIG. 7 is a throttle opening. It is a figure which shows the map of the initial setting value of. 1 ... Automobile, 2,3 ... driving wheels 4,5 ... driven wheels, 6 ... engine 7 ... slip detecting means 8 ... control amount setting means, 9 ... driving force control means, 10 ...
Skid control means 11 Road surface condition determination means, 12 …… Road surface state storage means 17 …… Throttle valve 18 …… Throttle motor 20 …… Control unit 21 to 24 …… Speed sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-237047 (JP, A) JP 60-128057 (JP, A) JP 60-197434 (JP, A)

Claims (1)

[Claims] 1. A slip detecting means for detecting the rotational speed of a drive wheel and the rotational speed of a driven wheel, and determining that the vehicle is slipping when the rotational speed of the drive wheel is a predetermined value or more than the rotational speed of the driven wheel. And a control amount setting means for setting a control amount for controlling the driving force when the slip detection means determines that a slip has occurred, and a driving force control for controlling the driving force based on the set control amount. In a skid control device for an automobile having a skid control means configured by means, during control by the skid control means, a road surface state determination means for determining the degree of slipperiness of the road surface based on the driving force control amount, And a road surface state storage means for storing information on a road surface frictional state determined by the road surface state determination means, wherein the control amount setting means stores the road surface state storage in the previous control. Skid control system of a motor vehicle, characterized by being configured for setting a control amount of the slip generated early on the basis of information about the road surface friction state stage is stored.