JPH065928Y2 - Anti-skid controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an anti-skid control device for preventing wheel lock by brake hydraulic pressure control.

(Prior Art) During braking of a vehicle, the rotation state of the wheels or the propeller shaft, that is, the deceleration or slip ratio of the wheels is detected, and the brake fluid pressure is adjusted so as to maintain a certain slip ratio according to the detected value. An anti-skid control device for controlling the vehicle to obtain maximum deceleration and lateral stability of the vehicle body is already known.

Here, for example, when the vehicle travels on a road surface having a high friction coefficient μ between the tire and the road surface, that is, a paved road, the anti-skid control device for high μ road anti-skid control means Skid control is performed,
When traveling on a road surface having a low friction coefficient μ, that is, on a snowy road, anti-skid control for low-μ roads is performed by the low-μ road anti-skid control means.
The determination of the high μ road and the low μ road is determined based on a signal from a G sensor (also referred to as an acceleration / deceleration sensor) mounted on the vehicle body. In addition, when the judgment of the high μ road and the low μ road based on the signal from the G sensor is added, this occurs when the braking force is increased and the anti-skid control is performed until the wheel tends to lock. This is because the deceleration of a moving vehicle is governed by the friction coefficient between the wheels and the road surface. That is, the deceleration (signal from the G sensor) generated in the vehicle at the time of shifting to the anti-skid control utilizes a phenomenon that it is low on the low μ road and high on the high μ road. For example, Japanese Patent Publication No. 58-47381. Are known from.

(Problems to be solved by the invention) Here, the vehicle equipped with the anti-skid control device is a low μ road having a relatively high road surface resistance such as a corrugated road, a gravel road, an uneven road, and a ground road, that is, a wheel. When traveling on a road surface with a low friction coefficient that gives a strong impact (hereinafter referred to as a bad road), the road surface resistance is high unlike snow roads as described above, so the wheels tend to lock when braking the vehicle. It is desirable to perform brake fluid pressure control, that is, anti-skid control for high μ roads to shorten the braking distance. However, if the conventional device is installed and the vehicle runs on the rough road, the low μ
Because of the road, the acceleration / deceleration in the traveling direction of the vehicle at the time of braking is small, and the low μ road signal is sent from the G sensor. Therefore, the anti-skid control for the low μ road, that is, the brake fluid pressure is immediately increased. The control to pull it out was made, and as a result, the braking distance was greatly extended, which was even dangerous.

An object of the present invention is to provide an anti-skid control device having excellent vehicle stability capable of shortening a braking distance when traveling on a low μ road having a relatively high road surface resistance such as a corrugated road, a gravel road, an uneven road, and a ground road. It is in.

(Means for Solving Problems) In order to achieve the above-mentioned object, the anti-skid control device of the present invention calculates a fluctuation frequency of a speed signal from each vehicle speed sensor when the brake is off, and the calculation means. The output from the means is compared with a predetermined value, and when the output is equal to or more than the predetermined value, a comparing means for sending a bad road signal as a bad road and a high μ for generating and sending a high μ road signal. When a brake-on signal is received after receiving the road signal generating means and the bad road signal, a high μ is used instead of the road surface μ signal from the G sensor.
The present invention is characterized by comprising a controller comprising switching means for sending the high μ road signal from the road signal generating means to the anti-skid control means.

(Operation) According to the present invention, the output from each wheel speed sensor is input to the calculation means, the fluctuation frequency of the wheel speed when the brake is off is calculated in the calculation means, and the fluctuation frequency is input to the comparison means. However, when the fluctuating frequency is equal to or higher than a predetermined value that can be regarded as a bad road by the comparison means, a bad road signal is input to the switching means. On the other hand, when the brake signal is also input to the switching means and the brake-on signal is received after the bad road signal is received, the high μ road signal from the high μ road signal generation means is replaced with the road μ signal from the G sensor. The brake fluid pressure is supplied to the skid control means, and the brake fluid pressure control for the high μ road is performed by the anti-skid control means for the high μ road.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an anti-skid control device showing an embodiment of the present invention. As shown in FIG.
The anti-skid control device of the present invention detects a G-sensor 1 that sends a high μ road signal when the vehicle is in high speed deceleration and a low μ road signal when the vehicle is in low acceleration / deceleration, and detects the speed of each wheel of the vehicle. A wheel speed sensor 30 that sends a speed signal corresponding to the speed, a brake switch 40 that detects the operation of the brake pedal and sends an on / off signal thereof, each modulator 50 that controls the brake fluid pressure of each wheel, and G sensor 1, wheel speed sensor 30 and brake switch
In response to the signal from 40, the controller 5 which sends a drive signal to each modulator 50 is provided. Here, the G sensor 1 and the wheel speed sensor 30 have known structures,
Each modulator 50 is also of a known type such as a hydraulic type or a pneumatic type in which hydraulic pressure or pneumatic pressure is used to control the brake hydraulic pressure by operating a solenoid, or an electric type in which the brake hydraulic pressure is directly controlled by operating a solenoid. When the controller 5 receives the high μ road signal during braking, it receives the high μ road anti-skid control means 64 for performing the brake fluid pressure control for the high μ road and the low μ road signal. Is an anti-skid control means composed of an anti-skid control means 65 for performing brake fluid pressure control for low μ roads.
66, a calculating means 62 for calculating the fluctuation frequency of the speed signal when the brake switch 40 is off, and the output from the calculating means 62 is compared with a predetermined value. However, the comparison means 63 for sending the bad road signal, the high μ road signal generating means 69 for generating and sending the high μ road signal, and the ON signal from the brake switch 40 when receiving the bad road signal In this case, the same function as the switching means 68 for sending the high μ road signal from the high μ road signal generating means 69 to the anti-skid control means 66 instead of the road surface μ signal from the G sensor 1 can be achieved. This is a configured microcomputer, and a program capable of achieving the above functions is written in the ROM in the controller 5 to store and process each set value and data table. The flowchart of the program written in the ROM is as shown in FIG.

The operation of this apparatus will be described below according to the program.

When the program starts, first the flag is set to 0 in step 1, and the process proceeds to step 2 and step 2
Then, each sensor, G sensor 1, wheel speed sensor
30. Read the output value from the brake switch 40 and proceed to step 3. In step 3, it is determined whether or not the brake switch 40 is on, that is, whether or not the brake pedal is depressed, and if it is depressed. If it is not depressed, the process proceeds to step 5. In step 5, the variable frequency of each wheel is calculated based on the output value from each wheel speed sensor 30, and the process proceeds to step 6, , It is determined whether or not the fluctuating frequency is equal to or higher than a predetermined value. Here, wavy roads, gravel roads, uneven roads,
The waveform of the wheel speed when traveling on a low μ road having a relatively high road surface resistance such as a ground road, that is, a bad road, may be a short sine wave having a short cycle or a short sine wave having a jagged shape on the waveform. Since it is known and the frequency at the time of the bad road is set as a predetermined value, if the calculated fluctuating frequency is equal to or higher than the predetermined value, it is judged as a bad road and the process proceeds to step 7, In step 7, the flag is set to 1, and then the process returns to step 2. On the other hand, if it is smaller than the predetermined value, it is determined that the road is not a bad road and the process proceeds to step 8. In step 8, the flag is set to 0 and then the process proceeds to step 2. Return. The predetermined value referred to here is a value determined experimentally. After returning to step 2, the process proceeds to step 2 and step 3 as described above, and if it is determined in step 3 that the brake switch 40 is on, that is, the brake pedal is depressed, step 4
Then, in step 4, it is determined whether or not there is a slip wheel. If there is no slip wheel, it is not necessary to perform anti-skid control, so the process returns to step 2. On the other hand, if there is a slip wheel, step In step 9, it is determined whether or not the flag is 0, that is, whether or not the road is a bad road. Here, if the flag is 0, it is determined that the road is not a bad road, and the process proceeds to step 11. If the flag is not 0, that is, if the flag is 1, the road is a bad road and the process proceeds to step 10. The anti-skid control, that is, the control for delaying the brake fluid pressure release timing in order to slightly lock the wheels is performed on the modulator, and then the process returns to step 2. On the other hand, if it is determined in step 9 that the road is not a bad road and the process proceeds to step 11, it is determined in step 11 whether or not the G sensor 1 is off. Step 10
Go to step 10, perform anti-skid control for high μ road, and then return to step 2. If it is on, that is, if running on low μ road that is not bad road such as snowy road, go to step 12. Then, in step 12, anti-skid control for the low μ road, that is, control for advancing the brake fluid pressure release timing to prevent the wheel locking tendency from being advanced is performed on the modulator, and then the process returns to step 2.

As described above, in the present invention, the anti-skid control for the high μ road is always performed during the control on the bad road regardless of the road μ signal of the G sensor, so that the braking distance is maintained while maintaining the vehicle stability. Can be significantly shortened.

For comparison, the inventor of the present invention examined the change over time in braking deceleration when driving on a rough road in order to compare the braking performance of the device of the present invention with that of the conventional device. In the case of the uneven road, which is called, the graph is as shown in Fig. 4. Here, the solid line A represents the case where braking is performed by conventional anti-skid control, that is, anti-skid control for low μ roads.
A one-dot chain line B shows the case where braking is performed by the anti-skid control of the present invention, that is, anti-skid control for high μ roads, and a dotted line C shows the case where braking is performed by a normal braking system without anti-skid control. There is. As is clear from this, it was proved in both figures that the device of the present invention has a larger braking deceleration and superior braking performance than the conventional device.

(Effects) As described above, according to the present invention, the fluctuation frequency of the wheel speed when the brake is off is calculated, and when the calculated value is equal to or higher than the predetermined value that can be regarded as a bad road, the brake for the high μ road is applied during braking. Since the hydraulic pressure control is performed, it is possible to greatly reduce the braking distance while maintaining the vehicle stability during braking on bad roads.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an antiskid control device showing an embodiment of the present invention, FIG. 2 is a flow chart of a program stored in the controller shown in FIG. 1, and FIG. 3 is the device of the present invention. Of the braking deceleration during traveling on a wavy road for comparing the braking performance between the conventional device and the conventional device, and FIG. 4 is a diagram for comparing the braking performance of the device of the present invention with that of the conventional device during traveling on the cross road. It is a time-dependent change figure of braking deceleration. 1 ... G sensor, 5 ... controller, 30 ... wheel speed sensor, 40 ... brake switch, 50 ... modulator, 62 ... calculating means, 63 ... comparing means, 64 ... high μ road anti-skid Control means, 65: anti-skid control means for low μ road, 66: anti-skid control means, 68: switching means, 69: high μ road signal generating means.

Claims (1)

[Scope of utility model registration request] 1. A wheel speed sensor for detecting each wheel speed of a vehicle and sending a speed signal corresponding to the wheel speed, a high μ road signal when the vehicle has a high acceleration / deceleration, and a low μ signal when the vehicle has a low acceleration / deceleration. Each of the wheels has a G sensor that sends out a road signal, a brake switch that detects ON / OFF of the brake, and a modulator that controls the brake fluid pressure in the brake pipe. In the locked state, when the high μ road signal is received, the brake fluid pressure control for the high μ road is performed by the high μ road anti-skid control means, and when the low μ road signal is received, the low μ road signal is low. In an anti-skid control device having anti-skid control means for preventing low μ road brake hydraulic pressure control by the road anti-skid control means, the speed signal when the brake is off And a comparing means for comparing the output from the calculating means and a predetermined value, and when the output is equal to or more than the predetermined value, a bad road signal is transmitted as a bad road. A high μ road signal generating means for generating and transmitting a high μ road signal, and after receiving the bad road signal,
When a brake-on signal is received, a controller comprising switching means for sending the high μ road signal from the high μ road signal generating means to the antiskid control means in place of the road surface μ signal from the G sensor. An anti-skid control device characterized by being provided.