JPS61244650A - Control device for starting on low mu road surface - Google Patents

Abstract

PURPOSE:To enable an easy start even on a low mu road surface by controlling a driving force for a wheel in such a way that the circumferential speed of said wheel agrees with a car speed, by a control means. CONSTITUTION:When a driver turns on a switch 43 and carries out a starting operation when starting on a low mu road surface such as a frozen road surface etc., a micro-processor 21 gives a certain signal to actuators 37, 38 to release the braking force of wheels 25-28. Then, the micro-processor 21 obtains a car speed from the speed sensors of wheels 27, 28, to judge whether a car has started or not. When the car speed is less than a defined speed, the micro- processor 21 judges that wheels are running idly and gives a control signal to an actuator 42 and moves a master cylinder 41, to increase the braking force against the wheels 25, 26.

Description

[Detailed Description of the Invention] [Summary] The present invention is designed to calculate the relationship between the vehicle speed and the circumferential speed of the wheels when starting on a road surface with an extremely low coefficient of friction (hereinafter referred to as a low μ road surface), such as a snowy road or an icy road. A control means is provided to control the braking force on the wheels so that the .mu.

[Industrial application field]

The present invention relates to a start control device for use on low μ road surfaces, such as snowy roads, icy roads, etc., which can facilitate starting on road surfaces with an extremely small coefficient of friction μ.

[Conventional technology]

When starting a vehicle on a low μ road surface with an extremely low coefficient of friction, such as a snowy road or frozen road, if the wheels spin, the vehicle cannot start. That is, if the wheels spin on a snowy road, they become buried under the snow surface, and if the wheels spin on an icy road, skidding occurs, making it impossible to start. In order to prevent such an inability to start, it is necessary to operate the accelerator, clutch, etc. to start at low speed and with an appropriate low torque, but this is quite difficult driving even for those accustomed to driving on snowy roads. It's technology.

[Problem that the invention seeks to solve]

The present invention solves the above-mentioned problems, and its purpose is to make it easier to start on a low μ road surface such as a snowy road.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention, as shown in the block diagram of FIG. speed detection means 4, and control means for controlling the braking force on the wheels 2 so that the detection results of the vehicle speed detection means 3 and the detection results of the circumferential speed detection means 4 match based on a start command on a low μ road surface. 5.

[For production]

Since the control means 5 controls the braking force on the wheels so that the speed of the vehicle and the circumferential speed of the wheels match, a low μ
It becomes possible to start easily even on the road surface.

[Embodiments of the invention]

FIG. 2 is a block diagram of an embodiment of the present invention, in which 21 is a microprocessor, 22 is a memory, 24 is an output section, and 24 is a block diagram of an embodiment of the present invention.
is an input unit, 25 is a right front wheel, 26 is a left front wheel, 27 is a right rear wheel, 28 is a left rear wheel, 29 to 32 are brake wheel cylinders, and 33 to 36 detect the rotational speed of each wheel 25 to 28, respectively. Speed sensor, 37 is brake wheel cylinder 2
9 an actuator compatible with the brake wheel cylinder 30, 39 an actuator compatible with the brake wheel cylinder 31, 32, 40 a 4-brake petal, 41 a master cylinder, 42 an actuator that operates the master cylinder 41, 43 is a switch that the driver turns on when starting on a low μ road surface. In this embodiment, the left and right front wheels 25 and 26 are drive wheels, and the left and right rear wheels 27 and 28 are non-drive wheels. It has the configuration shown in the figure, and 51 is a hydraulic pump;
52 is an oil tank, 53 is an electromagnetic solenoid, 54 is a coil spring, 55 is a cut valve, 56 is an oil chamber, 57 is a power piston, 58 is a cant valve, and 59 is a coil spring. Incidentally, when the signal b-d applied to the electromagnetic solenoid 53 is "0", the cut valve 55 in each actuator 37 to 39 operates as shown in FIG. 3(A).
Connect the path between the hydraulic pump 51 and the oil chamber, and send the signal b
When -d is 1'', as shown in FIG. 3(B), the path between the hydraulic pump 51 and the oil chamber 56 is blocked and the path between the hydraulic tank 52 is secured.

Further, FIG. 4 is a flowchart showing part of the processing contents of the microprocessor 21, and the operation of FIG. 2 will be explained below with reference to the same figure.

When starting on a low μ road surface such as a frozen road, the driver first turns on the switch 43 and then performs the starting operation.

Now. Microprocessor 21. When it detects that the switch 43 is turned on when the vehicle speed is zero, it starts the process shown in the flowchart of FIG. 1", "0", and "0" (step 31). When the signal becomes "1", the electromagnetic solenoid 53 in the actuator 39 is energized, and the cut valve 55 is opened between the hydraulic pump 51 and the oil chamber 56 as shown in FIG. 3(B). The path is blocked, and signals c and d
becomes “0”, the actuator 37.38
The inner cut valve 55 is in a condition to connect the path between the hydraulic pump s1 and the oil chamber 56 as shown in FIG. 3(A).

Next, the microprocessor 21 applies a control signal a to the actuator 42 via the output section 23 to bring the master cylinder 41 into a predetermined position (step 32). In this case, the cut valve 55 in the actuator vane 38
is in the state shown in FIG. 3(A), and the cut valve 58 is opened by the hydraulic pressure of the hydraulic pump 51. Therefore, the hydraulic pressure from the master cylinder 41 is applied to the brake wheel cylinders 4 and 30, and as a result, , a predetermined braking force is applied to the wheels 25,26. On the other hand, when the cut valve 55 in the actuator 39 is in the state shown in FIG. 3(B), the position shown in FIG. As shown in FIG. 2, the cut valve 58 closes and the power piston 57 moves to the left, so that no braking force is applied to the wheels 27, 28.

Next, the microprocessor 21 determines the vehicle speed ■ based on the detection results of the speed sensors corresponding to the wheels 27 and 28, which are non-driving wheels (step S3), and then determines whether the vehicle speed ■ determined in step S3 is greater than a predetermined speed. In other words, it is determined whether or not the start of the vehicle has been completed (step S4). If it is determined in step S4 that ■≦, the microprocessor 2 calculates the circumferential speed VR of the wheel 25 based on the detection result of the speed sensor 33 (step S5), and then combines the vehicle speed ■ found in step S3 with It is determined whether the circumferential speed VR and the peripheral speed VR are equal (step S6). If it is determined in step S6 that the vehicle speed V and the circumferential speed VR of the wheels 25 are equal,
That is, when it is determined that the wheels 25 are not spinning, the microprocessor 21 outputs the output signal d-1-'' from the output section 23.
1'' (step S7). As a result, the power piston 57 moves to the left as shown in FIG. 3(B), and the braking force on the wheels 25 is weakened.
If it is determined in step 6 that the vehicle speed V and circumferential speed VR are not equal,
That is, if it is determined that the wheels 25 are idling, the microprocessor 21 sets the output signal d of the output section 23 to 0'' (step s8), and then applies the control signal a to the actuator 42 to move the master cylinder 41. Let °wheel 2
5 (step S9).

Next, the microprocessor 21 determines the peripheral speed VL of the wheel 26 based on the detection result of the speed sensor 34 (step 510), and then calculates the vehicle speed V and peripheral speed ν determined in step S3.
It is determined whether or not L matches (step 511).

Then, in step Sll, the vehicle speed V and the circumferential speed VL of the wheel 26 are
If it is determined that these are equal, that is, if it is determined that the wheels 26 are not idling, the microprocessor 21 sets the output signal C of the output unit 23 to "I" (step 312),
After this, the process returns to step S3. As a result, the power piston 57 moves to the left as shown in FIG. 3(B), and the braking force on the wheels 26 is weakened. Also, step S
If it is determined in step 11 that the vehicle speed V is not equal to the circumferential speed VR, that is, if it is determined that the wheels 26 are spinning, the microprocessor 21 sets the output signal C of the output section 23 to O'' (step 513), the control signal a is applied to the actuator 42 to move the master cylinder 41, and the braking force to the wheels 2G is increased (step 514), after which the process returns to step S3.

If the determination result in step S4 is YES, it is assumed that the vehicle has started, and the control signal a is applied to the actuator 42 to end the operation of the actuator 42 (step 515), and then the output section 23 outputs the output signal b- All d are set to "0" (step 516), and the process is then terminated.

In the above-described embodiment, the process shown in the flow chart of FIG. Alternatively, the process shown in the flowchart of FIG. 4 may be executed, or the vehicle may be equipped with an ultrasonic sensor or the like that detects the road surface condition, and if the detection result of the sensor at the time of starting is a low μ road surface, the Of course, the process shown in the flowchart of FIG. 4 may also be performed.

It goes without saying that a temperature sensor may be further mounted on the vehicle, and if the temperature at the time of starting is low, the process shown in the flowchart of FIG. 4 may be performed.

In addition, in the case of automatic transmission vehicles,
Of course, when the vehicle speed is zero, the brake switch is on, and the accelerator switch is on, the process shown in the flowchart of FIG. 4 may be performed.

Further, although not explained in the above embodiment, the output signals b and d between the output parts may be always held at "0" except when starting (and the brake It goes without saying that the signals -d may be controlled so that the slip ratio between the wheels and the road surface becomes an appropriate value.Furthermore, in the embodiment described above, the speed sensor 35.
Although the speed of the vehicle is determined based on the detection results of the speed sensors 35 and 36, it is of course possible to determine the vehicle speed based on the detection results of the speed sensors 35 and 36 and the steering angle.

〔Effect of the invention〕

As explained above, the present invention provides vehicle speed detection means (in the embodiment, speed sensors 35 and 36) for detecting the vehicle speed of the vehicle.
, a microprocessor 21, etc.), a circumferential speed detection means for detecting the circumferential speed of the wheels of the vehicle (in the embodiment, it consists of a speed sensor 33, 34, a microprocessor 21, etc.), and a control for controlling the braking force for the wheels so that the detection result of the vehicle speed detection means and the detection result of the circumferential speed detection means coincide with a start command (in the embodiment, switch 43 is turned on); Since the vehicle is equipped with means (in the embodiment, it consists of actuators 37 to 39, 42, etc.), it has the advantage that it can easily start on a low μ road surface.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a block diagram of an embodiment of the present invention, FIG. 3 is a sectional view showing an example of the configuration of actuators 1 to 39, and FIG. 4 is a processing content of the microprocessor 21. FIG. 1 is a vehicle, 2.25 to 28 are wheels, 3 is a vehicle speed detection means,
4 is a circumferential speed detection means, 5 is a control means, 21 is a microprocessor, n is a memory, Yari is an output section, U is an input section, 29-
32 is a brake wheel cylinder, 33 to 36 are speed sensors, 42 is an actuator, Tochi is a brake pedal, 41 is a master cylinder, 43 is a switch, 51 is a hydraulic pump, 52 is an oil tank, 53 is an electromagnetic solenoid,
54 is a coil spring, 55 is a cut valve, 56 is an oil chamber, 57 is a power piston, 59 is a cut valve, and 59 is a power piston.
is a coil spring.

Claims (1)

[Scope of Claims] Vehicle speed detection means for detecting the vehicle speed of a vehicle; circumferential speed detection means for detecting the circumferential speed of the wheels of the vehicle; and a detection result of the vehicle speed detection means based on a start command on a low μ road surface. A start control device for a low μ road surface, comprising: control means for controlling a braking force on the wheels so that the detection result of the circumferential speed detection means coincides with the detection result of the circumferential speed detection means.