JP2898161B2 - Slip control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slip control device for suppressing a slip of a driving wheel of a vehicle at the time of starting and accelerating on a road surface having a low coefficient of friction, and more particularly, to suppressing a hunting and acceleration fluctuation to thereby improve stability. The present invention relates to an improved slip control device.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing a conventional slip control device described in, for example, JP-A-2-38150. In the figure, 1 is a driving wheel of the vehicle, 2 is a slip detecting means for detecting a slip amount J of the driving wheel 1 with respect to a road surface,
Reference numeral 3 denotes drive torque adjusting means for adjusting the drive torque T acting on the drive wheel 1.

Reference numeral 4 denotes control means for controlling the driving torque adjusting means 3. The driving torque adjusting means 3 is controlled so that the slip amount J becomes equal to the target slip amount Jo (generally, about 10% to 20% of the traveling speed). Feedback control is performed at the set response speed C. The set response speed C is a control amount for the drive torque adjusting means 3.

Reference numeral 5 denotes response speed changing means for changing the set response speed C based on the slip amount J. When the slip amount J becomes larger than the target slip amount Jo by a predetermined value or more, the drive torque T is reduced. The direction is changed so that the set response speed C increases.

Next, the operation of the conventional slip control device shown in FIG. 5 will be described. First, at the time of feedback control of the driving torque T, the driving torque adjusting means 3 is feedback-controlled by the control means 4 at the set response speed C.
Gradually becomes an appropriate value. Accordingly, the slip amount J of the drive wheel 1 is controlled to the target slip amount Jo, and the slip of the drive wheel 1 at the time of start and acceleration is appropriately suppressed while maintaining running stability of the vehicle.

When a re-slip occurs on the drive wheel 1 on a road surface having a low friction coefficient, the response speed changing means 5 responds to the slip amount J, so that the set response speed C in the feedback control of the control means 4 becomes: The value is changed to a large value in a direction to reduce the driving torque T of the driving wheel 1.
As a result, the re-slip quickly converges in a short time, and the slip of the drive wheel 1 is suppressed.

[0007]

As described above, in the conventional slip control device, the drive torque T for the drive wheels 1 is feedback-controlled at the set response speed C. Therefore, when the set response speed C is set to a small value. Convergence deteriorates, and conversely, if the set response speed C is set to a large value, hunting tends to occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a stable slip control device which has excellent responsiveness and has little hunting and acceleration fluctuation.

[0009]

SUMMARY OF THE INVENTION A slip control device according to the present invention includes a driving wheel speed detecting means for detecting a rotating speed of a driving wheel of a vehicle, a vehicle speed detecting means for detecting a running speed of the vehicle, and a rotational speed. And a slip amount calculating means for calculating a slip amount of the drive wheel based on the running speed, a target slip amount calculating means for calculating a target slip amount of the drive wheel based on the running speed, and a deviation between the slip amount and the target slip amount. , A slip change amount calculating means for calculating a temporal change amount of the slip amount, and a slip change direction determination for determining an increase or decrease of the slip amount deviation based on the slip amount deviation and the slip change amount. Means for calculating a control amount for the drive wheel based on a determination result from the slip change direction determining means and a slip amount deviation; Drive torque adjusting means for controlling the drive torque of the drive wheels, the control means comprising: a feedback gain switching means for switching a feedback gain of the control amount in response to the determination result; and Control amount calculating means for calculating the control amount, wherein the feedback gain switching means sets the feedback gain to a first value when the determination result indicates an increase in the slip amount deviation, and sets the feedback result to the slip amount deviation. Is set to a second value smaller than the first value.

[0010]

According to the present invention, the slip amount deviation is increased or decreased, that is, the actual slip amount approaches the target slip amount based on the difference between the target slip amount and the slip amount and the amount of temporal change in the slip amount. It is determined whether or not they are separated from each other, and the feedback gain for calculating the control amount is switched.

[0011]

【Example】

Embodiment 1 FIG. Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention, wherein 4A corresponds to the control means 4, and 1 to 3 are the same as those described above. 6 is the slip amount J and the target slip amount J
A slip amount deviation calculating means 7 for calculating a deviation ΔJ between the slip amount o and a slip change amount calculating means 7 for calculating a temporal change amount J ′ of the slip amount J.

Numeral 8 denotes a slip change direction judging means for judging a change direction of the slip. Based on the slip amount deviation .DELTA.J and the slip change amount J ', the slip amount deviation .DELTA.J increases or decreases, that is, the slip amount J becomes the target slip amount Jo. It is determined whether the vehicle is approaching or moving away from, and the determination result H is input to the control means 4A.

The slip detecting means 2 includes a driving wheel speed detecting means 21 for detecting a rotational speed R of the driving wheel 1, a vehicle speed detecting means 22 for detecting a running speed V of the vehicle, and a rotational speed R and a running speed V. Slip amount calculating means 23 for comparing and calculating slip amount J, and target slip amount calculating means 24 for calculating target slip amount Jo of drive wheel 1 by multiplying traveling speed V by a predetermined slip ratio. I have. Normally, the vehicle speed detecting means 22 sets the rotational speed of the driven wheel as the traveling speed V.

The control means 4A calculates the control amount C based on the slip amount deviation ΔJ and the feedback gain G, and the feedback gain switching means 41 for switching and setting the feedback gain G of the control amount C in response to the determination result H. And a control amount calculating means 42. In this case, the control amount C is not limited to the above-described set response speed, and various factors can be applied.

The feedback gain switching means 41 increases or decreases the feedback gain G for the control amount C in response to the determination result H. That is, the determination result H
Indicates that the slip amount deviation ΔJ (absolute value) increases, the feedback gain G is set to a relatively large first value. If the determination result H indicates that the slip amount deviation ΔJ (absolute value) decreases, The feedback gain G is set to a second value smaller than the first value.

The control amount calculating means 42 calculates a control amount C for bringing the slip amount J closer to the target slip amount Jo and reducing the slip amount deviation ΔJ to 0 by the feedback gain G.

FIG. 2 is a characteristic diagram showing the relationship between the driving force a and the lateral force b with respect to the slip ratio. The lateral force b is maximum when the slip ratio is 0 and decreases as the slip ratio increases. It can be seen that the maximum value is obtained when the slip ratio is around 0.2. Therefore, the slip ratio used in the calculation of the target slip amount Jo in the target slip amount calculation means 24 is set at around 0.2 (= 20%).

Next, the operation of the first embodiment of the present invention shown in FIG. 1 will be described with reference to the flowchart of FIG. First, signal input processing from various sensors (not shown) mounted on the vehicle body is performed, and the drive wheel speed detecting means 21
Detects the rotational speed R of the drive wheel 1, and detects the vehicle speed detecting means 22.
Detects the traveling speed V of the vehicle (step S1). Normally, the sensor signal is a pulse train corresponding to the number of revolutions, and thus is converted into a speed signal by calculation.

Subsequently, the slip amount calculating means 23 calculates the slip amount J based on the deviation between the rotational speed R and the running speed V, and the target slip amount calculating means 24 calculates the slip amount J based on the running speed V. Jo is calculated (step S2).

Next, the slip amount deviation calculating means 6 calculates a deviation between the slip amount J and the target slip amount Jo, that is, a slip amount deviation ΔJ. The slip change amount J 'is calculated (step S3). Also, the slip change direction determining means 8
Based on the slip amount deviation ΔJ and the slip change amount J ′, it is determined whether or not the absolute value of the slip amount deviation ΔJ has increased, and the determination result H is used as feedback gain switching means.
Input to 41 (step S4).

If the determination result H is YES, that is, if the slip amount J is departing from the target slip amount Jo and the absolute value of the slip amount deviation ΔJ is increasing, the feedback gain switching means 41 The feedback gain G is set to a large first value (step S5).

On the other hand, if the determination result H is NO, that is, if the slip amount J is approaching the target slip amount Jo and the absolute value of the slip amount deviation ΔJ is decreasing, the feedback gain switching means 41 , Feedback gain G
Is set to a second value smaller than the first value (step S
6).

Subsequently, the control amount calculating means 42 controls the driving torque adjusting means 3 based on the set feedback gain G.
Is calculated (step S7). The drive torque adjusting means 3 performs an output for controlling the drive torque T for the drive wheels 1 based on the control amount C (step S8).

Thus, when the slip amount deviation ΔJ is increasing, feedback control is performed by the control amount C based on the large gain so that the slip amount J quickly approaches the target slip amount Jo. Further, when the slip amount deviation ΔJ is decreasing, the slip amount J is approaching the target slip amount Jo, so that the feedback control is performed by the control amount C based on a small gain. Finally, a waiting time process for processing the above steps S1 to S8 in a fixed time is performed (step S9), and the process returns.

FIG. 4 shows the rotational speed R as the running speed V increases.
FIG. 4 is an explanatory diagram showing an example of the variation of R, where P1 is a control start point;
o is a target rotation speed, ΔR is a deviation of the rotation speed R from the target rotation speed Ro, and G1 to G8 are feedback gains that increase and decrease with time t. Here, the rotation speed R corresponds to the slip amount J, the target rotation speed Ro corresponds to the target slip amount Jo, and the rotation speed deviation ΔR corresponds to the slip amount deviation ΔJ.

In FIG. 4, the rotation speed R converges while oscillating with respect to the target rotation speed Ro, and a section in which the absolute value of the rotation speed deviation ΔR increases, and a section in which the absolute value of the rotation speed deviation ΔR decreases. Section appears alternately. That is, time
The first section group of t1 to t2, t3 to t4, t5 to t6, and t7 to t8 is a section in which the absolute value of the rotation speed deviation ΔR increases, and the time t2
A second group of sections t3, t4 to t5, t6 to t7, and t8 to t9 is a section in which the absolute value of the rotation speed deviation ΔR decreases.

Therefore, the first value during the increase of the rotational speed deviation ΔR
Feedback gains G1, G3, G5 for the section group
And G7 are set to large values, and the feedback gains G2 and G2 for the second section group during the decrease of the rotational speed deviation ΔR
G4, G6 and G8 are set to small values. Thus, the rotation speed R quickly converges to the target rotation speed Ro, as shown in the figure, and hunting and acceleration fluctuation are suppressed.

Embodiment 2 FIG. In the first embodiment, the first and second values set by the feedback gain switching means 41 are fixed values, but the slip amount deviation ΔJ
May be changed in a plurality of stages according to the degree of increase or decrease of the rotational speed deviation ΔR.

[0029]

As described above, according to the present invention, drive wheel speed detecting means for detecting the rotational speed of the drive wheels of the vehicle, vehicle speed detecting means for detecting the running speed of the vehicle, rotational speed and running speed Means for calculating the slip amount of the driving wheel based on the vehicle speed, means for calculating the target slip amount of the driving wheel based on the traveling speed, and calculating the deviation between the slip amount and the target slip amount. Slip amount deviation calculating means, slip change amount calculating means for calculating a temporal change amount of the slip amount, slip change direction determining means for determining increase or decrease of the slip amount deviation based on the slip amount deviation and the slip change amount, Control means for calculating a control amount for the drive wheel based on the determination result from the slip change direction determining means and the slip amount deviation; and driving of the drive wheel in response to the control amount A drive torque adjusting means for controlling the torque, a control means for switching a feedback gain of the control amount in response to the determination result, and a control for calculating the control amount based on the slip amount deviation and the feedback gain. And an amount calculating means, wherein the feedback gain switching means sets the feedback gain to a first value when the determination result indicates an increase in the slip amount deviation.
And if the determination result indicates a decrease in the slip amount deviation, the feedback gain is set to a second value smaller than the first value, and the actual slip amount is approaching or away from the target slip amount. Since the drive torque is determined by a control amount having a different feedback gain depending on whether the vehicle is running, there is an effect that a stable slip control device with excellent responsiveness and with little hunting or acceleration fluctuation can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a driving force and a lateral force with respect to a general slip ratio.

FIG. 3 is a flowchart showing an operation of the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a convergence operation of a drive wheel rotational speed according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a conventional slip control device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 drive wheel 21 drive wheel speed detecting means 22 vehicle speed detecting means 23 slip amount calculating means 24 target slip amount calculating means 3 drive torque adjusting means 4A control means 41 feedback gain switching means 42 control amount calculating means 6 slip amount deviation calculating means 7 Slip change amount calculation means 8 Slip change direction judgment means C Control amount G Feedback gain H Judgment result J Slip amount Jo Target slip amount ΔJ Slip amount deviation J 'Slip change amount R Rotation speed T Drive torque V Travel speed

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-108825 (JP, A) JP-A-63-12842 (JP, A) JP-A-4-272435 (JP, A) JP-A-2- 38150 (JP, A) JP-A-2-252930 (JP, A) JP-A-62-1199935 (JP, A) JP-A-3-202648 (JP, A) JP-A-4-179838 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) B60K 41/00-41/28 B60T 7/12-7/22 B60T 8/32-8/96 F02D 29/00-29/06 F02D 41 / 00-41/40

Claims (1)

(57) [Claims] A driving wheel speed detecting means for detecting a rotational speed of a driving wheel of the vehicle; a vehicle speed detecting means for detecting a running speed of the vehicle; a driving wheel speed detecting means for detecting a running speed of the driving wheel based on the rotating speed and the running speed. Slip amount calculating means for calculating a slip amount; target slip amount calculating means for calculating a target slip amount of the drive wheel based on the traveling speed; and a slip amount for calculating a deviation between the slip amount and the target slip amount. Deviation calculation means; slip change amount calculation means for calculating a temporal change amount of the slip amount; slip change direction determination means for determining increase or decrease of the slip amount deviation based on the slip amount deviation and the slip change amount A control means for calculating a control amount for the drive wheel based on a determination result from the slip change direction determining means and the slip amount deviation. And drive torque adjusting means for controlling the drive torque of the drive wheels in response to the control amount, wherein the control means switches a feedback gain of the control amount in response to the determination result. And a control amount calculating unit that calculates the control amount based on the slip amount deviation and the feedback gain, wherein the feedback gain switching unit is configured to perform the control when the determination result indicates an increase in the slip amount deviation. The feedback gain is set to a first value, and when the determination result indicates a decrease in the slip amount deviation, the feedback gain is set to a second value smaller than the first value. Slip control device.