JPH0662078B2 - 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 is suitable for a small slip without causing any trouble in steering operation while traveling on a curve. It has been devised to obtain driving force, and can be applied to four-wheel vehicles such as automobiles and tractors.

[Conventional technology]

As a driving force control device, a traveling characteristic value such as a slip ratio or a rotation speed of a driving wheel is compared with a threshold value set based on the rotation speed of a driven wheel, and a constant relationship is established with respect to this threshold value. In addition, there is known a configuration in which the braking force acting on the drive wheels is controlled so that the traveling characteristic value of the drive wheels is maintained.

[Problems to be solved by the invention]

Since the conventional control device always adopts a configuration in which the braking force is controlled for each of the left and right drive wheels, when the drive wheels on one of the left and right sides are being braked, the other side has no brake. However, during steering operation or when there is a left-right difference in the adhesion coefficient of the road surface, a large deviation in the traveling direction may occur only with the brake control for each wheel.

That is, when only the left drive wheel (1) enters the high adhesion road surface (R) in the curved road illustrated in FIG. 5, the driving force of only the left drive wheel (1) suddenly increases. Then, the slip becomes extremely small, and the vehicle, which was being steered in the direction of arrow D ₁ , is moving in the direction of arrow D ₂ due to the large driving force on the left side. Then, the problem that the vehicle slips appears.

[Means for solving problems]

This invention has been devised so that a suitable driving force can be obtained by eliminating the deviation in the traveling direction that occurs based on the difference between the driving forces of the left and right driving wheels on a curved road.
The configuration is the rotational speed of each of the driving wheel (1) and the driven wheel (2).
Rotational speed detection means (14), (15) for detecting (V _D ) (V _T ), vehicle speed calculation means (17), and a braking device for applying a braking force corresponding to the braking pressure (P) to the wheels ( and B), the threshold (threshold setting means for setting the V ₁₎ (16), by comparison of the running characteristic values of the drive wheel (1) for the threshold (V _1), driving wheels (1 ) Driving force control having a control unit (19) configured to instruct the brake device (B) to increase or decrease or maintain the brake pressure (P) in order to control the rotation speed (V _D ). The device is provided with a steering angle detecting means (S ₃ ) for detecting the steering angle (α), the detected steering angle (α) is equal to or greater than the angle threshold value (α _C ), and the vehicle speed (V) is for more vehicle speed threshold value (V _C), controls the left and right wheels co brake pressure, to perform the same or, if excluding the traveling state of the left and right drive wheels (1) every Additional control unit to perform control of the brake pressure (P) and standing (1
It is a driving force control device for a self-propelled vehicle characterized by comprising the above 9).

[Action]

In the case of straight traveling or low speed traveling on a curved road, the braking force control is performed on the left and right driving wheels (1),
Since it is performed every (1), excessive slip is promptly suppressed and each drive wheel (1), (1) exerts a suitable drive force, and the steering angle (α ) Above the angle threshold (α _C ), and when the vehicle speed (V) exceeds the vehicle speed threshold (V _C ), both the left and right drive wheels (1) and (1) are Since the same braking pressure will be controlled, the difference between the driving forces of the left and right drive wheels (1), (1) will be sufficiently small, and the turning operation will be performed as if operated by the steering wheel. It is something that will be done.

[Embodiment] Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows a circuit diagram of a driving force control device applied to an automobile as an example of a self-propelled vehicle, and FIG. 1 shows a block diagram thereof. For example, the front left and right drive wheels (1) , (1) and the following driven wheels (2), (2), the braking force acts by the action of the brake device (B), the illustrated brake device (B), respectively When the brake pedal (5) is stepped on the brake cylinder (4) provided corresponding to the rotors (3) of the wheels (1) and (2), pressure oil in the master cylinder (6) is propagated A pump (7) is supplied by opening or closing a hold valve (HV) or a delay valve (DV), which is supplied through a valve (PV) and a gate valve (GV) or controlled as described below. ), The brake piston (8) moves the brake shoe to the rotor (3).
It uses a structure that is pressed against.

Here, the proportioning valve (PV) has a function of changing the ratio of the amount of pressure oil supplied to the wheels (1), (2), and the gate valve (GV) is opened. The operation or closing operation switches the pressure oil in the master cylinder (6) to the brake cylinder (4) so that it can be supplied or cut off.The hold valve (HV) can be opened or closed. Therefore, transfer the pressure oil from the pump (7) to the brake cylinder (4).
Has a function of supplying or shutting off the supply, and the decay valve (DV) discharges or shuts off the pressure oil in the brake cylinder (4) by its opening or closing operation. . Further, the throttle device has a structure in which a fuel control valve is opened according to an operation amount of an accelerator operating member such as an accelerator pedal, and fuel of an amount corresponding to the opening is supplied to the engine.

Next, an example of the control means will be described. Left and right drive wheels
The rotation speeds of (1) and (1) are measured by the rotation sensor (S ₁ ), and the rotation speeds of the left and right driven wheels (2) and (2) are measured by the rotation sensor (S ₂ ). , For example, the rotational speeds (V _Da ), (V _Db on the left and right sides of the drive wheel (1) in the respective rotational speed calculation units (12) and (13) that are configured by using the microcomputer (11). ) And the rotation speed detecting means (14) and (15) for detecting the rotation speed (V _T ) of the driven wheel (2), respectively, and the threshold value (V ₁ as a control reference of the driving wheel (1) (V ₁ ) Is set by the threshold value setting means (16) based on the rotation speed (V _T ).

Further, the vehicle speed (V) is calculated by the vehicle speed calculation means (17) based on the rotation speed (V _T ) of the driven wheels (2), and the steering wheel is
The steering angle (α), which is the rotation operation amount of (18), is detected by the steering angle detection means (S ₃ ) configured by using, for example, a potentiometer, and is configured by the microcomputer (11). In the control unit (19), the rotation speed (V _Da ), (V _Db ),
The threshold value (V ₁ ), the vehicle speed (V), and the steering angle (α) are input respectively, and rotation as an example of the traveling characteristic value of the driving wheel (1) (for example, rotation speed, slip ratio, acceleration / deceleration), etc. The control unit (19) judges the position of the speed (V _Da ) and (V _Db ) with respect to the threshold value (V ₁ ), etc., and determines the gate valve (GV) and hold valve (HV). ), And a command for opening / closing control of each of the delay valve (DV).

That is, the changes in the rotational speeds (V _Da ) and (V _Db ) of the left and right drive wheels (1) and (1) and the changes in vehicle speed (V) and steering angle (α) are shown in the upper part of FIG. 3, respectively. For example, the opening and closing control status of the gate valve (GV) etc. is shown at the bottom of the figure for the left and right drive wheels.
As shown in (1) and (1) respectively, when a self-propelled vehicle is started,
The rotation speeds (V _Da ) and (V _Db ) rise rapidly, and at the time points (a ₁ ) and (b ₁ ) when the threshold value (V ₁ ) is reached, the respective gate valves (GV)
Closed to block pressure oil from the master cylinder (6) and supply pressure oil to the left and right brake cylinders (4) using the respective old valves (HV) to drive the left and right drive wheels (1). , (1) The brake is controlled so that the rotation speed (V _Da ), (V _Db ) reaches the maximum value and starts decelerating.
At (a ₂ ), (b ₂ ), the hold valve (HV) is closed and the brake pressure (P) in the brake cylinder (4) is maintained as it is, then the time (a ₂ ) below the threshold value (V ₁ ) ₃ ) and (b ₃ ), the decay valve (DV) is opened and the pressure oil in the brake cylinder (4) is discharged.After that, the rotation speed (V _Da ),
(V _Db ) and threshold (V ₁ )
The (HV) and the decay valve (DV) are basically controlled as described above.

The vehicle speed (V) exceeds the vehicle speed threshold (V _C ) preset by the vehicle speed threshold setting unit (20), and the steering angle (α) is equal to the angle threshold setting unit. When the angle threshold (α _C ) preset by (21) is exceeded, that is, in the zone (Z) of FIG. 3, the left and right drive wheels are
Both (1) and (1) are configured such that the control unit (19) outputs a command so that the brake pressure (P) is controlled to the same value. _Da ) and (V _Db ) are controlled so that the left and right drive wheels (1) and (1) are controlled together by the relationship of the higher rotational speed (V _Db ) to the threshold value (V ₁ ). It is configured (time points a ₄ , b ₄ , a ₅ , b ₅ ,
a _6).

When the steering angle (α) returns below the angle threshold (α _C ) after turning, the braking force control is performed again for each of the left and right drive wheels (1), (1). (Time points a ₇ , a ₈ , ..., And b ₆ ,
b ₇ , ...), and thus the stable driving force is controlled.

In the above-described embodiment, the case of front wheel drive is used, but the present invention can be applied to the case of rear wheel drive in the same manner as described above.

〔The invention's effect〕

The driving force control device for a self-propelled vehicle according to the present invention is configured as described above, and in the case of straight traveling or low speed traveling on a curved road, the braking force control is performed for each of the left and right driving wheels. Since it is performed every (1), (1), excessive slip is quickly suppressed and each drive wheel (1), (1)
Will produce a suitable driving force, and the steering angle (α) will be set to the angle threshold on a curved road.
(alpha _C) by operating above, and, when there was summer and the vehicle speed threshold value (V _C) or more of the vehicle speed (V) is left and right drive wheels (1), (1) both the same brake pressure Since the control will be performed, the difference between the driving forces of the left and right drive wheels (1), (1) will be sufficiently small, and as a result, an incorrect turning force due to the difference between the left and right drive torques will not appear. Therefore, the turning motion is performed smoothly as if the steering wheel was operated.

[Brief description of 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, FIG. 4 is a control flow chart, and FIG. [Fig. 3] is an explanatory diagram in a curve traveling. References (1) …… Drive wheels, (2) …… Driven wheels (14), (15) …… Rotation speed detection means (16) …… Threshold setting means, (17) …… Vehicle speed calculation means ( 19) …… Control unit, (P) …… Brake pressure (B) …… Brake device, (V _C ) …… Vehicle speed threshold (V) …… Vehicle speed, (V ₁ ) …… Threshold value (V _D ), (V _T ) …… Rotation speed (S ₃ ) …… Steering angle detection means (α) …… Steering angle (α _C ) …… Angle threshold

Claims (1)

[Claims] 1. A rotation speed detecting means for detecting respective rotation speeds of a driving wheel and a driven wheel, a vehicle speed calculating means, a brake device for applying a braking force corresponding to a brake pressure to the wheel, and a threshold value are set. By comparing the threshold value setting means and the driving characteristics of the driving wheels with respect to this threshold value,
A steering angle detection for detecting a steering angle in a drive force control device having a control unit configured to instruct the brake device to increase or decrease or maintain the brake pressure in order to control the drive force of the drive wheels. Means
If the detected steering angle is greater than or equal to the angle threshold value and the vehicle speed is greater than or equal to the vehicle speed threshold value, the brake pressure should be controlled to be the same for both the left and right wheels, and the above running conditions should be excluded. In this case, the drive force control device for a self-propelled vehicle is characterized in that the control unit is configured to control the brake pressure independently for each of the left and right drive wheels.