JP2002240692A - Electric brake system and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control an electric caliper even if a sensor for detecting an operation state of a brake pedal is broken and to carry out control having high resolution in the whole pedal operation range. SOLUTION: Plural sensors for detecting the operation state of the brake pedal are mounted to the brake pedal. The plural sensors are each provided with at least a leg-power sensor 13c, a stroke sensor 13a and a stroke sensor 13b. Piston thrusting values are calculated based on the leg-power output values and the stroke output values from the plural sensors, and the piston thrusting values are outputted to the respective electric calipers 11a-11d to control the electric calipers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric brake system and a computer program for controlling an electric caliper for applying a braking force to each wheel based on an output value from a sensor for detecting an operation state of an automobile brake pedal.

[0002]

2. Description of the Related Art An example of a conventional electric brake system is disclosed in Japanese Patent Application Laid-Open No. H11-171006. In the electric brake system disclosed in this publication, only one stroke sensor is provided for the brake pedal, and this stroke sensor is connected to the ECU. The ECU is connected to an electric caliper that applies a braking force to wheels. According to this electric brake system, when an output signal corresponding to the amount of depression of the brake pedal is issued from the stroke sensor, the ECU sends a control signal corresponding to the output signal of the stroke sensor to the electric caliper, and the electric caliper And exerts a predetermined braking force on the vehicle.

[0003]

In the above-mentioned conventional electric brake system, since there is only one sensor for detecting the operation state of the brake pedal, it cannot be confirmed whether or not the sensor value is correct. In addition, there has been a problem that the control of the electric caliper for applying a braking force to the wheel when the sensor has failed becomes impossible.

[0004] In general, brake pedal characteristics are as follows.
As shown in FIG. 2, when only the stroke sensor is used, the first half has a characteristic that the pedal pressure is increased more than the pedaling force and the second half has the characteristic that the pedaling power is increased more than the pedal stroke. There is a problem that the detection resolution in the high stroke area is inferior, and when only the tread force sensor is used instead of the stroke sensor, the detection resolution in the low tread force area is inferior.

In an electric brake system of this type, which detects the operation state of a brake pedal with a sensor, the pedal characteristics are mechanically created by a pedal simulator. Alternatively, the pedal characteristics cannot be accurately grasped by only one of the stroke sensors, and as a result, the electric caliper cannot be controlled according to the driver's pedal operation.

The present invention has been made in view of the above circumstances, and an object of the present invention is to control an electric caliper even when a sensor for detecting an operation state of a brake pedal has failed. Control with high resolution is possible in the pedal operation range of the electric brake system. Furthermore, even if the pedal simulator varies due to mechanical tolerances, the electric brake system and the electric brake system which can perform control according to the driver's pedal operation It is to provide a computer program to be executed.

[0007]

In order to achieve the above object, an electric brake system according to claim 1 of the present invention comprises:
A plurality of sensors for detecting the operation state of the brake pedal are provided on the brake pedal, and a plurality of electric calipers (the electric calipers 11a to 11c according to the embodiment) which apply a braking force to each wheel based on output values from the plurality of sensors. 11d
The plurality of sensors are a tread force sensor (tread force sensor 13c according to the embodiment) for detecting a tread force when a brake pedal is depressed.
) And a stroke sensor (corresponding to the stroke sensors 13a and 13b in the embodiment) for detecting a stroke when the brake pedal is depressed. The output value of the pedaling force from the pedaling force sensor and the stroke sensor Brake control means for calculating a piston thrust value based on the stroke output value, outputting the piston thrust value to each of the electric calipers, and controlling the electric calipers (the main controller 14 and the motor controller 12A, 12B).

In the electric brake system according to the second aspect of the present invention, the brake pedal is provided with a plurality of sensors for detecting the operation status of the brake pedal, and each wheel is controlled based on the output values from the plurality of sensors. An electric brake system that controls a plurality of electric calipers that provide power, wherein the plurality of sensors are a tread force sensor that detects a tread force when a brake pedal is depressed, and a stroke when the brake pedal is depressed. A target deceleration calculating means for calculating a target deceleration of the vehicle based on a treading force output value from the treading force sensor and a stroke output value from the stroke sensor. Equivalent) and the target deceleration of the vehicle calculated by the target deceleration calculation means,
A piston thrust calculating means for calculating a piston thrust value of an electric caliper provided on each of the front and rear wheels (corresponding to the main controller 14 in the embodiment); and a piston thrust value calculated by the piston thrust calculating means is converted into each electric caliper. (Refer to the motor controllers 12A and 12B of the embodiment).

A computer program according to a third aspect of the present invention provides a vehicle computer with a plurality of electric calipers for applying a braking force to each wheel based on output values of a pedaling force sensor and a stroke sensor provided on a brake pedal. A piston thrust value calculating process for calculating a piston thrust value based on a tread force output value from a tread force sensor and a stroke output value from a stroke sensor. An output process of outputting a value to each electric caliper is performed by the vehicle computer (corresponding to the main controller 14 and the motor controllers 12A and 12B of the embodiment).

In the present invention, since the electric caliper for applying a braking force to each wheel is controlled based on the detection values from the plurality of sensors for detecting the operation state of the brake pedal, only one of the plurality of sensors is used. Even in the case of failure, the electric lyper can be controlled. In addition, the stroke sensor exerts a high resolution in the first half of the pedal operation and the pedaling force sensor exerts a high resolution in the second half of the pedal operation. Becomes possible. Furthermore, even when the pedal simulator varies due to mechanical tolerances, the electric caliper control can be performed according to the driver's pedal operation because both the stroke sensor and the pedaling force sensor are used as described above.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric brake system according to an embodiment of the present invention will be described below with reference to FIG.

The electric brake system includes a brake pedal 1 operated by a driver and the brake pedal 1.
And a plurality (specifically, four) of electric calipers 11a, 11b, 11c that generate a braking force on the vehicle by being driven by an electric motor (not shown). , 11
and a plurality (specifically, two) of motor controllers 12A and 12B for controlling the electric motors of the electric calipers 11a to 11d.

The electric calipers 11a to 11d are mounted on the front, rear, left and right wheels of the vehicle. For example, an electric caliper 11a for the right front wheel and an electric caliper 11b for the left front wheel are provided by one motor controller 12A. The thrust of the pistons built in 11a, 11b is controlled via a motor, while the electric caliper 11 for the right rear wheel is controlled.
c and the electric caliper 11d for the left rear wheel are one motor controller 12B, and the thrust of the pistons built in the calipers 11c and 11d is controlled via a motor.

The electric brake system includes a plurality of, specifically, three sensors 13a, 13b, and 13c for detecting the operation status of the brake pedal 1, signals from the brake operation sensors 13a to 13c, and wheels (not shown). The plurality of motor controllers 12A and 12B based on a signal from a speed sensor, a signal from a wheel behavior sensor (not shown), and a signal from another controller (not shown).
And a main controller 14 that outputs a control signal such as a braking force command.

Further, in this electric brake system, the plurality of motor controllers 12A and 12B and the main controller 14 are provided with batteries 15A, 15B and 15C, respectively. That is,
The motor controller 12A includes the motor controller 1
A battery 15A for supplying power to 2A, a battery 15B for supplying power to the motor controller 12B is connected to the motor controller 12B, and a battery 15C for supplying power to the main controller 14 is connected to the main controller 14.

Here, all of the above-mentioned brake operation sensors 13a, 13b, 13c are connected to individual batteries 15A, 15B, 15C, respectively. That is, the brake operation sensor 13a has a battery 15A that supplies power to the brake operation sensor 13a, the brake operation sensor 13b has a battery 15B that supplies power to the brake operation sensor 13b, and the brake operation sensor 13c has a battery 15A that supplies power to the brake operation sensor 13c. Each of the batteries 15C to be supplied with power is connected.

The output signals of all the brake operation sensors 13a, 13b, 13c are output to the main controller 14 and all of the plurality of motor controllers 12A, 12B. That is,
The detection signal of the brake operation sensor 13a is transmitted to the main controller 14 and the plurality of motor controllers 12A, 1A.
2B, the detection signal of the brake operation sensor 13b is also output to the main controller 14 and the plurality of motor controllers 12A and 12B, and the detection signal of the brake operation sensor 13c is also output to the main controller 14 and the plurality of motor controllers. 12A and 12B.

During normal operation, as described above, the main controller 14 outputs signals from all the brake operation sensors 13a, 13b, 13c, signals from a wheel speed sensor (not shown), and signals from a wheel behavior sensor (not shown). A plurality of motor controllers 12A, 12B based on a signal, a signal from another controller (not shown), or the like.
Control signals such as a braking force command including anti-lock brake control (ABS control) and vehicle behavior control (VDC control) are output to the motor controller 12.
A and 12B are the electric calipers 1 based on the control signal.
1a to 11d are controlled. The main controller 14 and the motor controllers 12A, 12A
B functions as a brake control means for controlling the electric calipers 11a to 11d. The specific function will be clarified in the following description of the operation.

The brake operation sensors 13a, 13b, 13c for detecting the operation state of the brake pedal 1 are:
Two (for example, brake operation sensors 13a and 13b)
Is a stroke sensor for detecting a pedal stroke, and the remaining one (for example, the brake operation sensor 13c) is a pedaling force sensor for detecting a pedaling force.

Next, the operation of the electric brake system configured as described above will be described. Brake operation sensor 13a, 1
3b, 13c, based on signals output to the main controller 14, that is, the brake operation sensors 13a, 1
The main controller 14 outputs a control signal such as a braking force command to the motor controllers 12A and 12B based on the pedaling force output value and the stroke output value from 3b and 13c.
Thus, the electric calipers 11a to 11d are controlled normally.

Here, three brake operation sensors 13a
13c is input to the main controller 14. It is difficult to recognize the normal / abnormal state of the output value from one brake operation sensor. Operation sensors 13a to 13c
This is because it is possible to recognize normal / abnormal by comparing these output values with the output values. Therefore, when the output value of one of the three brake operation sensors is significantly different from the output values of the other sensors, the main controller 14 indicates that the sensor is abnormal. It can be displayed through the display means.

Note that the two stroke sensors 13a, 1
When 3b is normal, an average value of the sensor values is obtained, and control is performed based on the average value. When one of the two stroke sensors 13a and 13b is abnormal, control is performed using the output value of the normal sensor.

The three brake operation sensors 13
Each of a, 13b, and 13c includes at least one pedal force sensor and one stroke sensor for the following reason. That is, as described above, since the brake characteristics are as shown in FIG. 2, the detection resolution in the low pedaling force region is poor in the case of the control using only the pedaling force sensor, and the control using only the stroke sensor is not effective. In this case, there is a problem that the detection resolution in the high stroke area is inferior. However, as in the electric brake system shown here, control using a pedal force sensor and a stroke sensor requires high detection resolution in all pedal operation areas. It is possible.

As another reason, the brake pedal characteristics shown in FIG. 2 are mechanically produced by the pedal simulator 10, and therefore vary due to mechanical tolerances. Therefore, one of the pedaling force sensor and the stroke sensor cannot grasp the pedal characteristics, and as a result, there is a possibility that the electric section or the lipper cannot be controlled according to the driver's pedal operation. As shown in the electric brake system, the control uses the pedaling force sensor and the stroke sensor, so even if there is variation due to mechanical tolerances, it is possible to control the braking force according to the driver's pedal operation. It is.

A specific method of controlling the electric lypar on the basis of the pedaling force output value of the stroke sensor and the stroke output value of the pedaling force sensor will be described. Based on the pedaling force output value of the pedaling force sensor and the stroke output value of the stroke sensor , In the main controller 14,
The target deceleration of the vehicle is calculated by target deceleration calculation means incorporated therein. That is, the distance from the origin is calculated by substituting the pedaling force output value (N) from the pedaling force sensor and the stroke output value (mm) from the stroke sensor into the following equation (1) and storing the distance in advance in the storage unit of the main controller. The target deceleration is calculated from the map shown in FIG.

(Equation 1)

Here, A and B are coefficients for weighting one of the stroke sensor and the pedaling force sensor. C is a coefficient that satisfies the condition that the distance L from the origin is 100 when the stroke sensor and the pedaling force sensor are each at the maximum.

Next, based on the calculated target deceleration, piston thrust values of the electric calipers 11a to 11d, which are the ideal distribution of the front and rear wheels shown in FIG. 5, are calculated. Specifically, various conditions are substituted into the following equations (2) and (3), and the piston thrust value is calculated by the piston thrust calculation means built in the main controller 14.

(Equation 2) Note that the values of the front wheel axle load, the rear wheel axle load, the total load of the vehicle body, the height of the center of gravity, the wheel base, the effective radius of the tire, the effective radius of the disk, and the pad μ shown here are values that are naturally determined when the vehicle is determined.

Then, the piston thrust value calculated in this way is output in the form of an electric signal to each of the calipers 11a to 11d via the motor controllers 12A and 12B. As described above, the braking control by the electric caliper according to the driver's pedal operation can be performed. The operations of the main controller and the motor controller described above are executed by a computer program input in advance.

In the above embodiment, three sensors for detecting the operation state of the brake are provided. However, the present invention is not limited to this, and two or four or more sensors may be provided. In short, it is sufficient if there are a plurality of sensors, one of which is a pedaling force sensor and the other is a stroke sensor.

[0030]

According to the electric brake system according to the first aspect of the present invention, the electric caliper for applying a braking force to each wheel is controlled based on the detection values from the plurality of sensors for detecting the operation state of the brake pedal. Therefore, even if one of the plurality of sensors fails, the electric lyper can be controlled.The stroke sensor exhibits high resolution in the first half of the pedal operation and the pedaling force sensor exhibits high resolution in the second half of the pedal operation. Therefore, control with high resolution can be performed in all pedal operation areas. Further, even when the pedal simulator varies due to mechanical tolerances, the electric caliper control can be performed according to the driver's pedal operation because both the stroke sensor and the pedaling force sensor are used as described above.

According to the electric brake system of the present invention, the plurality of sensors detect a depression force sensor for detecting a depression force when the brake pedal is depressed, and detect a stroke when the brake pedal is depressed. A target deceleration calculating means for calculating a target deceleration of the vehicle based on a pedaling force output value from the pedaling force sensor and a stroke output value from the stroke sensor. Based on the target deceleration of the vehicle,
Since it has piston thrust calculation means for calculating the piston thrust value of the electric caliper provided for each of the front and rear wheels, and electric lyper control means for outputting the piston thrust value calculated by the piston thrust calculation means to each electric caliper, According to the driver's operation of the brake pedal, the electric calipers of the front and rear wheels can exert ideal braking force.

According to the computer program of claim 3 of the present invention, the invention of claim 1 can be suitably implemented.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an electric brake system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a pedal depression force and a pedal stroke of a brake pedal used in the electric brake system according to the embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a target control force and braking forces on front and rear wheels in the electric brake system.

FIG. 4 is a diagram showing a relationship between a distance L from an origin and a target deceleration in the electric bull brake system.

FIG. 5 is a diagram showing a relationship between deceleration and front and rear wheel piston thrust in the electric brake system.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Bureki pedal 10 Pedal simulator 11a-11d Electric caliper 12A, 12B Motor controller 13a, 13b Brake operation sensor (stroke sensor) 13c Brake operation sensor (pedal force sensor) 14 Main controller 15A-15C Battery

Claims (3)

[Claims] An electric motor for controlling a plurality of electric calipers for applying a braking force to each wheel based on output values from the plurality of sensors provided on a brake pedal for detecting an operation state of the brake pedal. A brake system, wherein the plurality of sensors include a pedal force sensor that detects a pedal force when a brake pedal is depressed, and a stroke sensor that detects a stroke when the brake pedal is depressed, the pedal force sensor And a brake control unit that calculates a piston thrust value based on a pedaling force output value from the vehicle and a stroke output value from a stroke sensor, outputs the piston thrust value to each of the electric calipers, and controls the electric calipers. An electric brake system characterized by the following. 2. An electric motor for controlling a plurality of electric calipers for applying a braking force to each wheel based on output values from the plurality of sensors provided on a brake pedal for detecting an operation state of the brake pedal. A brake system, wherein the plurality of sensors include a pedal force sensor that detects a pedal force when a brake pedal is depressed, and a stroke sensor that detects a stroke when the brake pedal is depressed, the pedal force sensor A target deceleration calculating means for calculating a target deceleration of the vehicle based on the pedaling force output value from the vehicle and a stroke output value from the stroke sensor; based on the target deceleration of the vehicle calculated by the target deceleration calculating means, Piston thrust calculating means for calculating a piston thrust value of an electric caliper provided for each of the front and rear wheels; Electric brake system, comprising an electric Ryaripa control means for outputting a piston thrust value calculated in unit each electric caliper. 3. A computer for a vehicle which functions as brake control means for controlling a plurality of electric calipers for applying a braking force to each wheel based on output values of a pedaling force sensor and a stroke sensor provided on a brake pedal. A computer program, comprising: a piston thrust value calculation process for calculating a piston thrust value based on a tread force output value from a tread force sensor and a stroke output value from a stroke sensor; and an output for outputting the piston thrust value to each electric caliper. And a computer program for causing the vehicle computer to execute the following.