JPH0723088B2 - Driving force control device for self-propelled vehicle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a driving force control device for a self-propelled vehicle such as an automobile, which improves riding comfort by controlling the rotational speed of driving wheels. It has been devised so that it can be applied to automobiles, tractors, motorcycles and the like.

[Conventional technology]

As a driving force control device, a slip characteristic of a driving wheel or a traveling characteristic value such as a rotation speed is compared with a threshold value set based on the rotation speed of a driven wheel, and a constant value is set with respect to this threshold value. Relatedly, there is known a control device that controls the braking force acting on the drive wheels so that the traveling characteristic value of the drive wheels is maintained.

[Problems to be solved by the invention] The conventional control device uses a value obtained by adding a constant value to the rotation speed of the driven wheels as a threshold value, or a value obtained by multiplying the rotation speed of the driven wheels by a constant ratio. I use it.

Thus, the threshold value is provided to preset the slip ratio of the drive wheels with respect to the driven wheels. Therefore, when the rotational speed of the driven wheel in the low speed range is A and the rotational speed of the same driven wheel in the high speed range is B, for example, a constant value C is applied to both rotational speeds.
If you calculate the slip ratio when Therefore, the slip ratio of the drive wheels in the high speed range becomes small, the frequency of controlling the rotation speed of the drive wheels in the high speed range increases, and a hunting phenomenon occurs and the riding comfort deteriorates.

Further, in the low speed range such as immediately after starting, the threshold value of the driven wheels is set so that the slip ratio of the driving wheels can be made as small as possible and efficient driving torque can be transmitted to the driving wheels. It is desirable that the value is not so large with respect to the rotation speed. However, as described above, the conventional calculation of the threshold value is performed by multiplying the rotation speed of the driven wheel by a constant value or a constant ratio, regardless of the speed range.
When a large drive torque is required for the drive wheels in the low speed range immediately after starting, the threshold value is far from the rotational speed of the driven wheels, so control delay for the drive wheels occurs. Therefore, the drive wheels slip due to the large drive torque, and the drive torque cannot be efficiently increased.

Therefore, in order to efficiently increase the driving torque in the low speed range and to prevent the hunting phenomenon due to the automatic brake control in the high speed range, there arises a technical problem to be solved. The present invention aims to solve the problems.

[Means for solving problems]

The present invention is one in which the threshold value is appropriately changed so that a suitable driving force is always exerted over each speed range, and the structure is the rotation speed detecting means of the driving wheel (1). (13) and rotation speed detection means (20) for the driven wheel (2)
A braking device (B) for applying a braking force corresponding to the braking pressure to the wheels, a threshold value setting means (14) for setting a threshold value (V ₁ ), and a threshold value (V ₁ ). It is configured to instruct the brake device (B) to increase or decrease or maintain the brake pressure in order to control the rotation speed (V _D ) of the drive wheel (1) by comparing the traveling characteristic values of the drive wheel (1). In the driving force control device having the control unit (17), the rotational speed (V _T ) of the driven wheel (2) is divided into a plurality of speed ranges, and the divided speed ranges are different from each other. A threshold value for each speed range is determined by adding a predetermined value, and the predetermined value for each speed range is set for each speed range in accordance with the increase in the rotation speed (V _T ) of the driven wheel (2). A driving force control device for a self-propelled vehicle, wherein the threshold value setting means (14) is configured so as to increase stepwise.

[Action]

A threshold value (V ₁ ) obtained by adding a non-constant predetermined value to the rotation speed (V _T ) of the driven wheel (2) is set in each speed range, and this predetermined value is set. Is determined so that the larger the rotation speed (V _T ) is, the larger the value becomes, and the threshold value (V ₁ ) is taken into consideration in consideration of fluctuations in friction coefficient, running resistance, etc. in the husband's speed range. Therefore, it is possible to expect driving force control in which the riding comfort is improved by reducing the frequency of controlling the rotation speed of the driving wheels over a wide speed range.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. Second
FIG. 1 shows a circuit diagram of a driving force control device applied to an automobile as an example of a motor vehicle, and FIG. 1 shows a block diagram thereof. For example, the left and right front drive wheels (1), (1 )
The braking force acts on the driven wheels (2) and (2) at the rear position by the action of the brake device (B), and the exemplified brake device (B) is the wheel (1). ), (2) to the brake cylinder (4) provided corresponding to the rotor (3), the pressure oil of the master cylinder (6) is pushed into the proportioning valve (PV) as the brake pedal (5) is depressed. Pressure oil of the pump (7) is supplied by the opening or closing operation of the hold valve (HV) and the delay valve (DV) which are supplied via the gate valve (GV) or controlled as described below. With the supply,
The brake piston (8) has a structure in which the brake shoe is pressed against the rotor (3). Here, the proportioning valve (PV) has a function of changing the ratio of the amount of pressure oil supplied to the wheels (1) and (2), and the gate valve (GV) is opened. The pressure oil of the master cylinder (6) can be supplied to the brake cylinder (4) or shut off from the supply of the master cylinder (6) by an operation or a closing operation. The hold valve (HV) can be opened or closed. Therefore, it has a function of supplying or shutting off the pressure oil of the pump (7) to the brake cylinder (4), and the decay valve (DV) is opened or closed in the brake cylinder (4). The pressure oil of
Alternatively, the discharge is cut off. Further, in the illustrated throttle device, the fuel control valve (10) is opened in accordance with the operation amount of the accelerator operating member (9) such as the accelerator pedal, and the amount of fuel corresponding to this opening is supplied to the engine. Is.

Next, an example of the control means will be described. Each drive wheel (1)
The rotation speed of the drive wheel (1) is measured by the rotation sensor (S ₁ ) and the rotation speed calculation unit (12) configured by the microcomputer (11) (for example, rotation speed). , Slip rate, acceleration, etc.) and a rotation speed detection means (13) for detecting a rotation speed (V _D ) as an example,
A threshold value (V ₁ ) as a desired rotation speed for controlling the rotation speed of the drive wheel (1) is calculated by the threshold value setting means (14). That is, the rotation speed detected by the rotation sensor (S ₂ ) is used as the rotation speed calculation unit (15) of the driven wheel (2).
Is calculated as the rotation speed (V _T ) of the driven wheel (2), and a predetermined value that differs according to this rotation speed (V _T ) in the threshold setting unit (16) is added, for example. The threshold value (V ₁ ). That is, the predetermined value may be determined based on the rotational speed (V _T) the friction coefficient or the running resistance or the like is brought calculated according to the magnitude of the driven wheel (2).

If the predetermined value (ΔV) determined in the low speed range of the rotation speed (V _T ) of the driven wheel (2) is used as it is in the high speed range of the rotation speed (V _T ), The slip rate in the high speed range is smaller than the slip rate in the low speed range where the rotation speed (V _T ) is low. For this reason, the frequency of controlling the rotation speed of the drive wheel (1) is increased and the riding comfort is deteriorated. Therefore, as shown in the upper part of FIG. 3, in the low speed range of the rotation speed (V _T ), a small value (ΔV ₁ ) or (ΔV ₂ ) is set to the rotation speed of the driven wheel (2). The threshold value (V ₁ ) is set to a small value by adding it to (V _T ). Further, in the speed range where the rotation speed (V _T ) is high, a large predetermined value (ΔV ₃ ) or (ΔV ₄ )
Was added to the rotation speed (V _T ) of the driven wheel (2) to set the threshold value (V ₁ ) to a large value. Thus, the threshold value (V ₁ ) makes it possible to obtain a friction coefficient of 10 to 30% in each speed range of the drive wheel (1) which is the most appropriate value.

The control unit (17) provided in the microcomputer (11) for controlling the brake device (B) determines the rotation speed (V _D ) of the drive wheel (1) with respect to the threshold value (V ₁ ). The gate valve (GV), the hold valve (HV), and the delay valve (DV) can be instructed to open / close by judging whether the size is larger or the speed is further increased. That is, the variation of the rotational speed (V _D ) of the drive wheel (1) is shown in the upper part of FIG. 3, and the gate valve (G
V), etc., and the progress of the brake pressure in the brake cylinder (4) at the bottom of the figure, when the motor vehicle is started, the gate valve (GV)
If the hold valve (HV) and the day valve (DV) are both closed when is opened (step,
), The braking operation by the brake pedal (5) remains possible.

Next, based on the rotation speed (V _T ) of the driven wheel (2), one of the corresponding predetermined values (ΔV ₁ ), (ΔV ₂ ), etc. is read (step,) and, for example, V _T The threshold value (V ₁ ) is calculated by adding V ₁ (step). When the rotation speed (V _D ) reaches the threshold value (V ₁ ) for the first time (time point t _{0 in} FIG. 3), the gate valve (GV) naturally remains open, so that the gate valve (GV) When closed, the hold valve (HV) is opened, pressure oil is supplied to the brake cylinder (4), and the brake operates (steps ,,), and thereafter, the rotation speed (V _D )
The difference between the previous time point and the current time point will be detected to determine whether or not the speed is increasing. If the rotation speed (V _D ) is equal to or higher than the threshold value (V ₁ ) and the speed is increasing. If so (ta, tb, tc in Fig. 3), the hold valve (HV) is opened and the day valve (DV) is closed (step,), so the pressure oil of the pump (7) enters the brake cylinder (4). The supplied brake pressure will increase, and the rotation speed (V _D )
Is above the threshold value (V ₁ ) and is not accelerating (td, te, tf in Fig. 3), both the hold valve (HV) and the decay valve (DV) are closed. The pressure oil in the brake cylinder (4) is retained, and when the rotation speed (V _D ) falls below the threshold value (V ₁ ) (tg, th, ti), hold valve (HV)
Is closed and the decay valve (DV) is opened (step), the pressure oil in the brake cylinder (4) is discharged, the brake pressure is reduced, and these control operations are repeated to drive wheels ( The slip of 1) gradually disappears (ti in Fig. 3). When the rotation speed (V _D ) does not exceed the threshold value (V ₁ ) even after a certain time t ₁ seconds has elapsed since the hold valve (HV) opened (tx in FIG. 3). ) Is the one in which the gate valve (GV) is opened and the decay valve (DV) is closed to end the above-mentioned braking force control, and the driving wheel (1) does not exceed the threshold value (V ₁ ). With the rotation speed (V _D ) approaching the rotation speed (V _T ) of the driven wheel (2), a stable driving state with a small slip is maintained.

Further, in the above-mentioned embodiment, the number of drive wheels (1) is singular,
A plurality of them may be used, a generator type rotation sensor may be used as the rotation speed detection means (13), and the brake device (B) may be either air or hydraulic pressure.

In FIG. 2, reference numeral (18) is a pressure switch and reference numeral (19).
Is an accumulator.

〔The invention's effect〕

As described above, the driving force control apparatus for a self-propelled vehicle according to the present invention divides the rotational speed (V _T ) of the driven wheel (2) to provide a plurality of different speed ranges, and the speed ranges are respectively different according to the speed range. setting a plurality of predetermined values different Tsu, a predetermined value selected on the basis of the rotational speed of the driven wheels (2) (V _T), speed (V _T) of the driven wheel (2) and said predetermined value Thus, the threshold value (V ₁ ) is calculated and set. Therefore, drive wheels (1)
The friction coefficient range in each speed range can be set with a threshold value (V ₁ ) that takes into consideration fluctuations in running resistance and the like. Thus, the coefficient of friction of the road surface that is not constant over a wide speed range can be effectively used, and the occurrence of hunting can be suppressed and the driving force control with improved riding comfort can be performed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention. FIG. 1 is a block diagram of a control device, FIG. 2 is a circuit diagram of the control device, FIG. 3 is a control characteristic diagram, and FIG. It is a flow chart. Explanation of symbols (1) …… Drive wheels (2) …… Driven wheels (13), (20) …… Rotation speed detecting means (14) …… Threshold setting means (17) …… Control section (B)… Brake device (V ₁ ) Threshold value (V _D ), (V _T ) ... Rotation speed

Claims (1)

[Claims] 1. A rotating speed detecting means for a driving wheel, a rotating speed detecting means for a driven wheel, a brake device for applying a braking force corresponding to a brake pressure to a wheel, and a threshold value setting means for setting a threshold value. And a control unit configured to instruct the brake device to increase or decrease or maintain the brake pressure in order to control the rotation speed of the drive wheel by comparing the traveling characteristic value of the drive wheel with this threshold value. In the driving force control device, the rotational speed of the driven wheel is divided into a plurality of speed ranges, and a different threshold value is added to each of the divided speed ranges to obtain a threshold value for each elementary range. And the threshold value setting means is configured such that the predetermined value for each speed range is increased stepwise for each speed range in accordance with the increase in the rotational speed of the driven wheel. A driving force control device for a self-propelled vehicle that features.