JP2003081075A - Braking force control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly control a jackknife phenomenon and thrust up to a tow car by a towed vehicle in combination vehicles where the towed vehicle is supported turnably at a joining point that is set on the tow car as center. SOLUTION: A braking force control device includes means for detecting road gradient (step 1-step 5), means for detecting the total weight of combination vehicles (step 6-step 9), means for controlling, when the vehicles are braked, the braking timing of a towed vehicle to be relatively faster than the braking timing of a tow car in accordance with the road gradient and the total weight of the combination vehicles. In steps 11 to 13, when he vehicle are braked, the device controls the rate of allocation of braking force to the tow car and allocation of braking force to the towed vehicle in accordance with the road gradient and the total weight of the combination vehicles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force control device for an articulated vehicle.

[0002]

2. Description of the Related Art There are trailer swing phenomenon and jack knife phenomenon as vehicle behavior peculiar to a connected vehicle. Particularly, the jack knife phenomenon is apt to occur during braking during traveling on a downhill. This is because when the braking timing of the towed vehicle (starting time of brake operation) is delayed from the braking timing of the towing vehicle (starting time of brake operation), the towed vehicle goes straight while expanding the connection angle with respect to the towing vehicle. This is probably because Therefore, by electrically detecting the depression of the brake in the towing vehicle and transmitting this to the brake device of the towed vehicle as an operation signal, the time difference between the braking timing of the towed vehicle and the braking timing of the towed vehicle ( There is one that eliminates the time lag (JP-A-9-
No. 58442).

[0003]

However, depending on the gradient of the road surface, the towed vehicle pushes up the towed vehicle with a large inertial mass even if the towed vehicle is braked in synchronism with the braking of the towed vehicle. This may cause the connection angle to be bent, which makes it difficult to control (vehicle speed control) especially when turning.

The present invention has been made in view of these problems, and provides a means for appropriately suppressing the jack knife phenomenon and the thrusting of the towed vehicle by the towed vehicle during braking of the vehicle. With the goal.

[0005]

According to a first aspect of the present invention, there is provided a connecting vehicle for rotatably supporting a towed vehicle about a connecting point set on the towing vehicle, the means for detecting a slope of a road surface, and the connecting vehicle. Means for detecting the gross weight, and means for controlling the braking timing of the towed vehicle when the vehicle is being braked so as to be earlier than the braking timing of the towing vehicle according to the slope of the road surface and the total weight of the connected vehicles. It is characterized by being provided.

According to a second aspect of the present invention, in a connected vehicle in which a towed vehicle is rotatably supported around a set connecting point in the tow vehicle, a means for detecting a slope of a road surface and a means for detecting a total weight of the connected vehicle. And means for controlling the ratio of the braking force distribution to the towing vehicle and the braking force distribution to the towed vehicle when the vehicle is braked, according to the slope of the road surface and the total weight of the connected vehicles. .

According to a third aspect of the present invention, in the braking force control device according to the first or second aspect of the invention, the means for detecting the total weight of the connected vehicle is a means for detecting the operating state of the towing vehicle, and a towing vehicle. Means for determining whether the vehicle is accelerating on a flat road based on the driving state of the vehicle;
Estimated value M of the total vehicle weight based on the equation of motion M = F / α
And means for obtaining.

[0008]

According to the first aspect of the present invention, the braking timing of the towing vehicle and the braking timing of the towed vehicle are not always controlled to be constant, but the slope of the road surface and the total weight of the connected vehicle (loading of the towed vehicle). Depending on the quantity), the towed vehicle side is controlled earlier than the towed vehicle side. For this reason,
When the towed vehicle is braked, the towed vehicle is pulled from the rear, and the connection angle is extended. Therefore,
Regardless of the slope of the road surface or the total gravity of the connected vehicle, it is possible to properly prevent the towing vehicle from being pushed up by the towed vehicle and the jack knife phenomenon in which the connection angle is abnormally bent.

In the second invention, the ratio (distribution ratio) of the braking force distribution to the towing vehicle and the braking force distribution to the towed vehicle is
It is controlled according to the total weight of the connected vehicle and the gradient of the road surface. Therefore, when the total weight of the connected vehicle increases and the slope of the road surface (in particular, the degree of descending slope) increases, the distribution ratio on the towed vehicle side becomes larger than the distribution ratio on the towing vehicle side. , A braking force distribution ratio suitable for the load capacity of the towed vehicle is obtained, and the towed vehicle is pushed up by the towed vehicle even during braking while traveling downhill, and the connection angle is abnormally bent. Occurrence can be accurately prevented.

In the third invention, the total weight of the connected vehicle can be accurately estimated without using the weight of the towed vehicle and the load sensor for detecting the weight of the towed vehicle. Further, when the means for detecting the gradient of the road surface is composed of means for detecting the rotational speed and the accelerator opening degree of the engine mounted on the towing vehicle, the means for detecting the total weight of the connected vehicle is provided with these detection signals. Can be realized at low cost.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of FIG. 1, 30 is a tractor (towing vehicle) and 40 is a trailer (towed vehicle), which are connected via a coupler (fifth wheel coupler). 20 to 23 are brake chambers that generate braking force on the wheels of the towing vehicle, 24 and 25 are brake chambers that generate braking force on the wheels of the towed vehicle, 1 is a control unit mounted on the towing vehicle, and 2 is a control unit 1. The modulator 3, which controls the brake pressure (braking force) to be supplied to the brake chambers 20 to 23 of the towing vehicle 30 based on the brake operating signal from the controller 3, also receives the brake chamber 24 of the towed vehicle 40 based on the brake operating signal. , A modulator for controlling the brake pressure (braking force) supplied to 25,
Is. The modulators 2 and 3 are connected to the control unit 1 via serial communication.

The control unit 1 suppresses the towed vehicle 40 from pushing up the towed vehicle 30 during braking and the occurrence of the jack knife phenomenon in which the connection angle is abnormally bent. Each vehicle 3
The braking force distribution to 0 and 40 is controlled as described later. For this control, in the towing vehicle 30, the brake opening sensor 1 for detecting the opening of the brake pedal (the amount of brake operation)
3, an accelerator opening sensor 11 for detecting the opening of the accelerator pedal (accelerator operation amount), an engine rotation sensor 12 for detecting the rotation speed of the engine, and the like.

FIG. 2 is a block diagram showing the configuration of the control system, in which the control unit 1 uses the degree of downhill (the gradient of the downhill) and the degree of uphill (the gradient of the uphill) as parameters to control the braking timing and the braking force distribution ratio, respectively. The control characteristic (see FIGS. 3 to 6) is set. Reference numeral 29 is a means for detecting an uphill / downhill state, and is composed of an engine rotation sensor 12 and an accelerator opening sensor 11.

Based on these detection signals (detection value of engine rotation speed, detection value of accelerator opening), the control unit 1 rotates the engine when the accelerator opening is not> 0 (accelerator opening = 0). The differential value of the speed is determined as the downhill degree. When the accelerator opening is> 0, when the differential value of the engine rotation speed is lower than the reference value P (driving data on a flat road) predicted from the accelerator opening, the difference from the reference value P is used to determine the degree of climbing (engine It is determined as the differential value of the rotation speed / accelerator opening (see FIG. 7).

The control characteristics shown in FIGS. 3 to 6 are settings in which the total weight of the connected vehicle is based on a standard value (for example, the minimum total weight of the connected vehicle) and correspond to changes in the total weight of the connected vehicle. The unit 1 has a function of detecting the total weight of the connected vehicle and changing the control characteristics of the braking timing and the braking force distribution ratio based on the total weight. 9 and 10 are data maps used for this correction processing, in which a correction amount is set according to the total weight of the connected vehicles (total vehicle connection weight).

In FIG. 2, 28 is a means for changing the braking force distribution ratio, 27 is a means for changing the braking timing, and the control unit 1 is the brake opening sensor 1
Based on the detection signal of No. 3, the total braking force (requested braking force) required of the connected vehicle is obtained from the data map as shown in FIG. The total braking force for the towing vehicle 30 is shown in FIG. 6 with the braking timing for adding the correction amount shown in FIG. 9 to the control characteristic shown in FIG.
10 is added to the control characteristic of FIG. 10, the total braking force with respect to the towed vehicle 40 and the towed vehicle 30 is determined as shown in FIG. The braking timing is controlled according to the control characteristic so that the distribution is performed at a ratio according to the braking characteristic shown in FIG. When the degree of descending slope> 0 is determined, the total braking force for the towed vehicle 40 and the towed vehicle 30 is added to the control characteristic of FIG. The correction amount is controlled to be distributed at a ratio.

The reference value P of the data map (see FIG. 7) used to determine the degree of climbing is given an initial value based on the maximum total weight of the connected vehicles (running data on a flat road). Therefore, regardless of the change in the load capacity of the towed vehicle, the function of changing the setting when the total weight of the connected vehicles is detected by the control unit 1 is appropriately determined in order to appropriately determine the degree of climbing. Be prepared.

FIG. 11 is a flow chart for explaining the control contents of the control unit 1, which is repeatedly executed at a predetermined control cycle. In steps 1 and 2, the accelerator opening and the engine speed are read. In step 3, it is determined whether or not the accelerator opening> 0. If the determination in step 3 is yes, step 4
On the other hand, when the determination in step 3 is no, the process proceeds to step 5.

In step 4, the differential value of the engine speed is calculated from the reference value predicted from the accelerator opening (the initial value is set to the running data on the flat road in the maximum gross weight state of the connected vehicle). If is also low, the degree of climbing (differential value of engine speed / accelerator opening) is determined. In step 5, the degree of descending slope (differential value of engine speed) is determined.

Steps 6 to 9 are processed in parallel with step 4. In step 6, the vehicle is accelerating on a flat road (the rate of increase of the accelerator opening is ≧ 0,
Moreover, it is determined whether or not the degree of climbing = 0). Step 6
If the judgment is no (not accelerating on a flat road),
While jumping to step 10, the determination in step 6 is yes
If (accelerating on a flat road), proceed to step 7.

In step 7, vehicle acceleration α =
Calculate (Vn-Vn-1) / (tn-tn-1). The vehicle acceleration α is obtained as the amount of change (Vn-Vn-1) in the vehicle speed V per unit time (tn-tn-1). The vehicle speed V is calculated from the engine rotation speed and the reduction ratio of the power transmission system (the transmission shift stage is a variable). In step 8, the engine output per unit time (tn-tn-1) (engine rotation speed x engine shaft torque) is obtained from the accelerator opening and the engine rotation speed based on the engine performance curve (output characteristics). The vehicle driving force F is calculated by adding the reduction ratio of the power transmission system to this. In step 9, the total weight M of the connected vehicle is calculated from the vehicle acceleration α and the vehicle driving force F by the equation of motion M = F / α.

In step 10, the brake opening is read. In step 11, brake opening> 0
Determine whether or not. If the determination in step 11 is no, the process jumps to END, while if the determination in step 11 is yes, the process proceeds to steps 12 and 13.

In step 12, the required braking force (total braking force) corresponding to the brake opening is obtained from the data map (see FIG. 8). In step 13, FIG.
~ Based on the control characteristic of Fig. 6 and the correction amount according to the total weight M of the connected vehicle of Figs. 9 and 10, the distribution ratio of the total braking force and the braking timing to the towing vehicle 30 and the towed vehicle 40 are determined. To control. The reference value P in FIG. 7 is changed to a setting P ′ (running data on a flat road) that matches the total weight M of the connected vehicles calculated during acceleration running on a flat road (see FIG. 7).

With this structure, when the vehicle is being braked, the towed vehicle 40 side is braked earlier than the towed vehicle 30 side in accordance with the gradient of the road surface and the total weight of the connected vehicles, and the total braking force is reduced. The distribution is also controlled to an appropriate ratio according to the slope of the road surface and the total weight of the connected vehicles, so that the braking force of the towed vehicle 40 pulls the towing vehicle 30 from the rear, and the connection angle is extended. Like Therefore, even when the descending grade is steep, the towed vehicle 40 is prevented from going straight so as to push up the tow vehicle 30, and the jack knife phenomenon in which the connection angle is abnormally bent can be appropriately suppressed. Therefore, the control of the connected vehicle (vehicle speed control, etc.) during turning while descending a slope is much easier than before.

Even when braking during climbing, similar control is performed based on the degree of climbing, so that pushing up of the towed vehicle 40 onto the towing vehicle 30 is suppressed, and the driver can easily and safely perform the braking operation. The effect is obtained. in this case,
The total weight of the connected vehicle is calculated from the equation of motion M = F / α, and by using the detection signals of the means for detecting the gradient of the road surface (engine rotation sensor 12 and accelerator opening sensor 11), Accurate detection can be obtained at low cost.

The road gradient and the total weight of the connected vehicles may be detected by appropriate sensors. In that case, since the total weight of the connected vehicles does not affect the detection signal (actual measurement value) of the appropriate sensor that detects the slope of the road surface, the reference value P does not need to be changed without depending on the map data as shown in FIG. The control becomes simple. According to the detection signal (actual measurement value) of the sensor, the total weight of the connected vehicle is not limited to the detection during the acceleration traveling on the flat road. Therefore, the correction amounts in FIGS. 9 and 10 can be calculated from the start of the control. 3-
It becomes possible to add to the control characteristic of FIG.

By detecting the friction coefficient of the road surface in the control unit 1, the correction amount corresponding to the friction coefficient is obtained from the data maps as shown in FIGS. 12 and 13, and these are used as the control characteristics shown in FIGS. Additional control is also conceivable.

[Brief description of drawings]

FIG. 1 is a plan configuration diagram of an articulated vehicle that represents an embodiment of the present invention.

FIG. 2 is a block diagram of a control system of the same.

FIG. 3 is a characteristic diagram showing a braking timing according to a degree of descending slope.

FIG. 4 is a characteristic diagram similarly showing a braking timing according to a degree of climbing a slope.

FIG. 5 is a characteristic diagram showing a braking force distribution ratio according to the degree of descending slope.

FIG. 6 is a characteristic diagram similarly showing a braking force distribution ratio according to the grade of climbing.

FIG. 7 is a characteristic diagram that similarly illustrates the grade of climbing.

FIG. 8 is a characteristic diagram similarly showing a total braking force according to a brake opening degree.

FIG. 9 is a characteristic diagram similarly showing a correction amount of the braking timing according to the total vehicle weight.

FIG. 10 is a characteristic diagram showing a correction amount of the braking force distribution ratio according to the total vehicle weight.

FIG. 11 is a flowchart for explaining the control contents of the control unit.

FIG. 12 is a characteristic diagram similarly showing a correction amount of a braking timing according to a road surface friction coefficient.

FIG. 13 is a characteristic diagram showing a correction amount of braking force distribution according to a road surface friction coefficient.

[Explanation of symbols]

1 control unit 2,3 Braking force modulator 11 Accelerator position sensor 12 Engine rotation sensor 13 Brake opening sensor 20-23, 24, 25 Brake chamber 27 Braking timing changing means 28 Braking force distribution changing means 30 towing vehicle 40 towed vehicle

Claims (3)

[Claims] 1. A connected vehicle in which a towed vehicle is rotatably supported around a connecting point set on a towing vehicle, means for detecting a slope of a road surface, means for detecting a total weight of the connected vehicle, and A braking force control device comprising: means for controlling the braking timing of the towed vehicle during braking so as to be relatively earlier than the braking timing of the towing vehicle according to the gradient of the road surface and the total weight of the connected vehicles. . 2. A connected vehicle in which a towed vehicle is rotatably supported around a connecting point set on the towing vehicle, means for detecting a slope of a road surface, means for detecting a total weight of the connected vehicle, and A braking force control device comprising: means for controlling the ratio of the braking force distribution to the towing vehicle and the braking force distribution to the towed vehicle at the time of braking according to the slope of the road surface and the total weight of the connected vehicles. . 3. The means for detecting the total weight of a connected vehicle includes a means for detecting the operating state of a towing vehicle, a means for determining from the operating state of the towing vehicle that the vehicle is accelerating on a flat road, and a flat road. A means for obtaining the vehicle acceleration α and the vehicle driving force F from the driving state of the towing vehicle during acceleration traveling, and means for obtaining the estimated value M of the total vehicle weight based on the equation of motion M = F / α. Either claim 1 or claim 2
And a braking force control device.