JPH0367901B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application This invention relates to a brake control method for an automobile, and particularly to a brake control method that controls the brake so that the effectiveness of the brake remains almost constant regardless of changes in the payload. .

(b) Prior Art The effectiveness of automobile brakes changes depending on various driving conditions, such as the number of passengers, the weight of cargo, the slope of the road, and the coefficient of friction of the friction material of each brake. In automobiles, drivers are required to vary the force on the brake pedal in response to changes in various driving conditions.

Therefore, the applicant has proposed a brake control method that does not require such operations, that is, a brake control method that always provides constant brake effectiveness with a constant brake pedal force regardless of changes in driving conditions. In particular, a patent application has been filed (Japanese Patent Application No. 128738/1982).

The invention according to the above application is based on the fact that the various driving conditions that affect the effectiveness of the brakes, such as the number of passengers on board, do not change as frequently as shown in the figure above. average,
Alternatively, brake control data obtained from past brake control that is not very old compared to the present, such as the effectiveness at a time when the current brake operation was reversed by a minute amount of time in the past, is collected as reference data, and this is used as reference data. It is designed to be used as control data. According to such a control method, brake control can be performed without any time delay from the time the pedal is operated until the required deceleration is obtained.

The above brake control method is based on the premise that various driving conditions do not change as frequently as shown above, and there will be almost no problems even if it is applied to an actual car based on this premise. it is conceivable that.

(c) Problems to be solved by the invention Regarding brake control, which directly affects the safe driving of automobiles, it is necessary to take measures that are as safe and reliable as possible, so when considering the above method from this perspective, it is found that the above method does not meet the standards. It cannot be denied that there is some time delay between the time when the data is collected and the time when the brakes are actually operated, so it is possible that the load may change due to changes in personnel and cargo during that time. Probability cannot be reduced to zero.

Changes in live load are a factor that greatly affects brake effectiveness, so as long as the probability of such changes occurring during the above time delay is non-zero, it is important to take measures to ensure safety and certainty. This is necessary for performing brake control.

Therefore, the present invention provides a brake system that corrects the above data by the amount of change when a change in live load occurs between the collection time of data serving as a reference for brake control and the time of actual brake operation. The purpose is to provide a control method.

(d) Means for Solving the Problems In order to achieve the above object, the present invention adds a vehicle weight detection sensor to the configuration of the prior art described above, and provides a sensor between the standard data collection time and the brake operation time. When a change in vehicle weight is detected by the sensor, a data correction signal is sent to the processing device.

The basic technical idea of this invention will be explained in more detail as follows.

First, the content of the above-mentioned prior art will be explained based on the attached drawings.

FIG. 1 shows an example of a preferable relationship between the pedal depression force F and the vehicle deceleration β. For example, it is determined as follows: β=aF (a is a proportionality constant), and this is input into the information processing device and stored.

Now, at a past point in time when the output P of the actuator that operates the brake fluid pressure generator (master cylinder) is P _o-1 , the vehicle deceleration β at that time is β _o-1
, and if the relationship between the two is a constant proportional relationship, the relationship between the two becomes β _o-1 =bP _o-1 (b is a constant of proportionality) as shown in the graph of FIG. If this relationship is input and stored in the information processing device, when the actuator output P _o during the current brake operation is detected, the above stored data will be referred to and the current deceleration β _o will be calculated as β _o = bP _o . It can be estimated.

On the other hand, since the preferable relationship between pedal depression force F and vehicle deceleration β is stored as shown in FIG.
A preferred deceleration β ₁ (β ₁ =aF ₁ ) corresponding to the pedal force F ₁ during the current brake operation is immediately determined.
Therefore, the required deceleration can be obtained by controlling the output of the actuator from the information processing device so that the estimated deceleration β _o described above becomes β ₁ , that is, P _o =a/bF ₁ . can.

Although the above description has been made on the assumption that the relationships between β and P and β and F have a simple proportional relationship, the same can be said when these have an arbitrary functional relationship.

On the other hand, when a change in the vehicle weight is detected by the vehicle weight detection sensor, the information processing device changes the proportionality constants a and/or b to correct the relationship between the output P _o and the pedal force _F1 , The actuator is controlled based on the correction result. As a result, brake control can be performed based on data corresponding to changes in live load.

(E) Embodiment FIG. 3 shows a partial block diagram of an apparatus for carrying out the method of the present invention.

In the figure, 1 is a brake booster;
A brake pedal 3 is connected to the input shaft 2, and a master cylinder 5 is connected to the output shaft 4. The brake booster 1 is divided into output side and input side pressure chambers 7 and 8 by a piston 6, and outlet side oil passages 10 and 11 of a control valve 9 are connected to each pressure chamber 7 and 8,
A drive pressure source 12 such as hydraulic pressure, pneumatic pressure, or vacuum pressure is connected to the inlet side of the control valve 9 .

Further, a pedal force detection sensor 13 is provided between the input shaft 2 and the piston 6, and an output detection sensor 14 is provided between the output shaft 4 and the piston 6. type information processing device 15 (hereinafter simply referred to as processing device 15)
electrically connected to the

A front wheel brake 17 is connected to the master cylinder 5 via an oil passage 16, and a rear wheel brake 20 is connected via an oil passage 18 and a pressure reducing valve 19.

In addition, the vehicle body has a vehicle deceleration detection sensor 21,
A vehicle weight detection sensor 22 is provided, and each sensor 21, 22 is electrically connected to the processing device 15.

The above vehicle weight detection sensor 22 is connected to the vehicle 2.
3. It detects the total load applied to the suspension system or the load applied to a part of it. For example, a load cell is inserted in series with the path that substantially bears the load of the automobile, and the vertical displacement of the suspension system is detected. There are some that detect the fluid pressure of the fluid suspension system, and others that calculate from the natural frequency of the suspended part.

Furthermore, the deceleration of a vehicle can be detected by detecting the rotational speed of an axle, or by inertial force acting on a weight.

A preferable relationship between the pedal depression force F and the vehicle deceleration β is set, for example, as shown in FIG. 1, and is input and stored in the processing device 15.

The processing device 15 also has a relationship between the output P of the actuator and the deceleration β obtained from the detection signal of the output detection sensor 14 and the corresponding detection signal of the deceleration detection sensor 21 (see FIG. 2). ) in chronological order and memorize it. As a result, the processing device 15 stores the relationship between P and β at a certain point in the past.

Further, a detection signal from the vehicle weight detection sensor 22 is input to the processing device 15, and is used as a correction signal for the above-mentioned stored data.

Now, the driver depresses the brake pedal 3 and the output P _o of the actuator 1 is detected, and the processing device 15
is input, the processing device 15 refers to the actuator output P _o-1 at a certain point in the past (for example, during the previous braking) and the corresponding deceleration β _o-1 , and determines the deceleration β from the relationship between the two. Estimate _o .

On the other hand, by operating the brake pedal 3 mentioned above,
When the pedal force F ₁ is detected and input to the processing device 15, the processing device 15 can determine a preferable deceleration β ₁ corresponding to the pedal force F, and the estimated deceleration β _o is determined to be β ₁ The control valve 9 is operated to control the output P _o of the actuator 1 so that the output P o approaches .

In this case, if it is detected by the input from the vehicle weight detection sensor 22 that there is a change in the vehicle weight between the previous brake operation and the current brake operation, the stored data is changed according to the change. is corrected, and the output P _o is controlled according to the correction result.

(F) Effect The brake control method of the present invention is as described above, and when performing brake control with reference to past data, the load load is calculated between the time of collection of reference data and the time of actual brake operation. When there is a change in the stored data, the stored data can be corrected according to the change. Therefore, the effect of keeping the braking effectiveness substantially constant, which is achieved by a constant pedal depression force, can be more effectively achieved in accordance with actual conditions.

[Brief explanation of drawings]

Figure 1 shows brake pedal depression force F and vehicle deceleration β
2 is a graph showing the relationship between actuator output P and vehicle deceleration β, and FIG. 3 is a block diagram showing an embodiment of the present invention. 1...actuator, 2...input shaft, 4...
Output shaft, 5... Master cylinder, 6... Piston, 7, 8... Pressure chamber, 9... Control valve, 13...
Pedal force detection sensor, 14...Output detection sensor, 15...Processing device, 21...Deceleration detection sensor, 22...Vehicle weight detection sensor.

Claims (1)

[Claims] 1 It has an actuator that operates the brake fluid pressure generator, a pressure control valve that acts on the actuator, a vehicle deceleration detection sensor, a pedal depression force detection sensor, and an actuator output detection sensor, and Using an electronic information processing device that processes signals and outputs control signals to the control valve, inputting and storing a preferable relationship between vehicle deceleration and pedal depression force into the processing device;
The relationship between vehicle deceleration during brake operation and actuator output is input and memorized in time series, and the vehicle deceleration relative to the current actuator output is estimated based on the past data in the above time series, and the estimated reduction is calculated. In a brake control method for an automobile, in which the processing device controls the actuator output through the control valve so that the speed becomes a preferable deceleration corresponding to the current pedal depression force, a vehicle weight detection sensor is provided and the reference data is collected. A brake control method for an automobile, characterized in that when a change in vehicle weight is detected by the sensor between a brake operation time and a brake operation time, a data correction signal is sent to a processing device.