JP2005028941A - Brake control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake control device free of the risk to become a redundancy system even if it is based on the electric system. <P>SOLUTION: The brake control device is to make brake by-wire control, whereby a braking force is generated by at least one system even if the brake by-wire control is interrupted by a fail-safe controlling means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a brake control device including an electric brake control device.
[0002]
[Prior art]
Conventionally, for example, a technique disclosed in Patent Literature 1 is disclosed as a system for electrically controlling the braking devices of all four wheels. In this publication, since all four wheels are electrically controlled, safety is ensured by providing a power supply system and a supply line with a dual system or more in order to ensure a braking force when the electric system fails.
[0003]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 2000-25591 (see page 4, lower right, FIG. 2).
[0004]
[Problems to be solved by the invention]
However, in the above-described prior art, all systems are redundant systems such as a duplex system from the viewpoint of safety in order to ensure the braking force, so that the system becomes complicated and the cost increases. There was a problem.
[0005]
The present invention has been made paying attention to the above-described problems, and an object of the present invention is to provide a brake control device that does not become a redundant system even if an electric brake control device is used.
[0006]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention is a brake control device that performs brake-by-wire control, and is configured to obtain braking force by at least one system even when the brake-by-wire control is stopped by the fail-safe control means.
[0007]
Therefore, even if the power supply system and the supply line are in a failed state and electric control cannot be performed, the braking force can be reliably obtained. Further, since it is not necessary to configure a redundant system, the cost can be reduced.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
FIG. 1 is a system diagram showing the overall configuration of the first embodiment. The brake system in the present embodiment is composed of a plurality of systems. The unit F is a hydraulic brake-by-wire control unit that controls the operation of the front wheel braking units B1 and B2 based on the braking command signal from the unit M. On the other hand, in the units R1 and R2, an electric brake control means for controlling the operation of the rear wheels B3 and B4 based on the braking command signal from the unit M is provided in each rear wheel. Each front and rear wheel is provided with wheel speed sensors V1S, V2S, V3S, V4S for detecting the wheel speed. These wheel speed sensor values V1, V2, V3, V4 are transmitted to the unit M.
[0009]
The brake pedal 1 is provided with three pedal sensors SEN1, SEN2, and SEN3. Here, as described in SAE981109, as required performance specific to brake-by-wire, there are three performances so that accurate measurement (that is, detection of the driver's operation intention) can be performed even when one sensor fails. In view of the demand for the pedal sensor, the first embodiment also includes three pedal sensors.
[0010]
The unit S is a unit that detects the pedal operation information of the driver, converts the output signals S1 and SEN3 of the SEN1 into electric signals, and transmits them to the unit M. Further, the unit S is configured to be able to communicate with the units R1 and R2.
[0011]
Unit M is a unit that calculates front and rear wheel braking force and transmits a braking command to each unit. Further, the unit M converts the output signal S2 of SEN2, which is the driver's pedal operation information, into an electrical signal. As described above, the pedal sensor signal is converted into an electrical signal by the two units S and M, and even if there is an abnormality due to a sensor failure or the like, it can be reliably detected by either unit. .
[0012]
The unit M is supplied with power from an ignition switch SW1 signal, a brake lamp switch SW2 signal, wheel speed sensor signals (V1, V2, V3, V4) and a power supply source (battery or the like) E. Further, the target braking force is calculated based on the signals S1 and S3 input from the unit S, the signal S2, and other sensor information related to the brake control. Then, braking commands T1, T2, and T4 are transmitted to the unit F, the unit R1, the unit R2, and the unit BG by communication.
[0013]
Further, the unit M supplies the power source E1 of each unit with the on operation of the brake lamp switch SW1 or the ignition switch SW2 as a trigger. On the other hand, the unit is configured to be able to supply or hold power to each unit for a certain period of time with the ignition switch SW1 being turned off as a trigger, and then the power supply is shut off.
[0014]
The unit F is configured such that the motor and valve control in the unit can be feedback-controlled by a hydraulic pressure monitor using the hydraulic pressure sensors WP1 and WP2 based on the braking command from the unit M. The front wheel side brake actuator will be described later.
[0015]
Units R1 and R2 are electric brake actuators, each having a control communication line for each rear wheel. Further, the motor and the like in the unit can be controlled based on the braking command from the unit M. This electric brake applies a braking force to the rear wheel based on the pedal operation information of the driver, and generates a braking force by pressing a brake pad against a brake disk by a motor or the like, for example. Further, when operating a brake generator 9 to be described later, the rear wheel side brake actuator 6 generates a braking force by subtracting the braking force generated by the brake generator 9 from the required braking force of the rear wheel. The rear wheel side that employs an electric brake does not generate braking force when the system is shut down during a failure. However, the rear wheel has a smaller braking force than the front wheel (generally, the braking force ratio between the front wheel and the rear wheel is about 7: 3). Even if the brake-by-wire control fails, the braking force is sufficient only with the front wheel. Can be secured.
[0016]
The unit BG is a brake generator, and controls the braking force of the brake generator based on the braking command from the unit M. That is, on the rear wheel side, in addition to the units R1 and R2, a brake generator 9 that generates a braking force by generating electric power by the rotational force of the wheels, and a unit BG that controls the operation of the brake generator 9 are provided. The unit BG monitors the SOC (State of charge) of a battery that can be stored outside the figure, and transmits the SOC to the unit M. Further, the operation of the brake generator 9 is controlled based on the command signal of the unit M.
[0017]
The unit O is another unit related to vehicle operation (for example, an engine unit, an automatic transmission unit, or the like), and transmits and receives information to and from the unit M.
[0018]
Each unit described above is connected by two communication lines, and is roughly divided into a front wheel control system of units S, F, and M and a rear wheel control system of units S, M, units R1, R2.
[0019]
[Configuration of unit F]
FIG. 2 is a circuit diagram showing an oil passage configuration of unit F. Since the hydraulic pressure is basically supplied to the right front wheel FR and the left front wheel FL with the same circuit configuration, only the oil path configuration of the left front wheel FL will be described.
[0020]
A shutoff valve 61 is provided in the oil passage 3c. The shut-off valve 61 is provided with a so-called normally open type that is opened when the power is turned off. During normal brake-by-wire control, the shut-off valve 61 is always closed to shut off the master cylinder pressure.
[0021]
Further, a pump 67 that generates hydraulic pressure by driving the motor 68 is provided. The pump 67 is driven based on a command signal from the unit M and generates a necessary hydraulic pressure. The generated hydraulic pressure is supplied to the oil passage 31 via the one-way valve 66. An oil passage 36 having a relief valve 65 is connected to the oil passage 31. When the hydraulic pressure in the oil passage 31 increases too much, the brake fluid is relieved from the relief valve 65 to the reservoir 4.
[0022]
A pressure increasing valve 63 is provided between the oil passage 31 and the oil passage 32. A piston 64 is provided between an oil passage 35 that supplies hydraulic pressure supplied from the master cylinder side to the wheel cylinder side and an oil passage 32 that executes brake-by-wire control. A pressure reducing valve 62 is provided between the oil passage 32 and the oil passage 34 connected to the reservoir 4.
[0023]
An isolation valve 69 is provided between the oil passage configuration of the left front wheel FL and the oil passage configuration of the right front wheel FR. The isolation valve 69 controls the independent / independent state of the oil path configuration of the left front wheel FL and the oil path configuration of the right rear wheel FR. For example, when the same hydraulic pressure is supplied to both front wheels and a sufficient hydraulic pressure can be discharged by one pump, the isolation valve 69 is opened and only one pump is driven. Even when the two pumps 67 and 77 are driven, the same hydraulic pressure is supplied to both front wheels by opening the isolation valve 69.
[0024]
(Brake-by-wire pressurization control)
At the time of pressurization of the front wheel brake by wire, the shutoff valve 61 is closed, the pressure increasing valve 63 provided in the oil passage 31 is opened, and the pressure reducing valve 62 provided in the oil passage 32 is closed. When the hydraulic pressure is supplied from the pump 67, the hydraulic pressure is supplied to the oil passage 31 via the one-way valve 66. This hydraulic pressure is supplied to the piston 64 and strokes the piston 64. By this piston stroke, hydraulic pressure is supplied to the oil passage 35 and the wheel cylinder pressure is increased.
[0025]
(During brake-by-wire decompression control)
At the time of pressure reduction of the front wheel brake by wire, the shutoff valve 61 is closed, the pressure increasing valve 63 provided in the oil passage 31 is closed, and the pressure reducing valve 62 provided in the oil passage 32 is opened. Then, the brake fluid accumulated in the wheel cylinder is reduced in pressure by returning to the reservoir 4.
[0026]
(When system shuts down due to failure)
If any failure occurs in the brake-by-wire control system, the system is shut down. At this time, the shut-off valve 61 is opened and the pressure increasing / decreasing valves 62 and 63 are closed. Thereby, the hydraulic pressure supplied from the oil passage 3c from the master cylinder side is supplied to the front wheel braking means B1 and B2.
[0027]
That is, the unit F includes a pump 67 → one-way valve 66 → oil passage 31 → pressure increasing valve 63 → oil passage 32 → oil passage 33 → piston 64 as a brake-by-wire system. On the other hand, as a normal brake system, an oil passage 3c → an isolation valve 61 → an oil passage 35 is configured. And since these two brake systems are connected via the piston 64, even if a failure occurs in the brake-by-wire system, braking can be performed using an independent normal brake system. It is configured.
[0028]
[Normal braking action]
FIG. 3 is a flowchart showing a normal braking action in the control configuration.
In step 101, the driver's pedal operation is detected by SEN1, SEN2, and SEN3.
In step 102, the sensor values S1 and S3 are converted into electric signals in the unit S and transmitted to the unit M by communication and electric signals.
In step 103, the sensor value S2 is converted into an electric signal in the unit M and transmitted to the unit S by communication and an electric signal.
In step 104, the braking force calculation of the front wheels and the rear wheels is performed in the unit M based on the pedal operation information S1, S2, S3, and the braking command value is transmitted to the unit F and the units R1, R2 through the communication system.
In step 105, the motor and valve control in the unit F are performed in the unit F based on the braking command value from the unit M, and the feedback control of the front wheel braking means B1 and B2 is performed.
In step 106, the unit M transmits a braking command value to the units R1, R2 and the unit BG based on the SOC transmitted from the unit BG to the unit M and the calculated rear wheel required braking force, and the rear wheel braking means. The operation of B3 and B4 is controlled.
[0029]
[Operation when unit M is abnormal]
FIG. 4 is a flowchart showing the operation when the unit M is abnormal.
In step 201, the microcomputer abnormality in the unit M is determined. If the microcomputer is abnormal, the process proceeds to step 204; otherwise, the control flow is terminated.
[0030]
In step 202, an abnormality of the power supply circuit is determined. If the power supply circuit is abnormal, the process proceeds to step 204, and otherwise the control flow is terminated.
[0031]
In step 203, it is determined whether the communication line is abnormal. If the communication line is abnormal, the process proceeds to step 205. Otherwise, the control flow ends.
[0032]
In step 204, the microcomputer in the unit M is stopped.
[0033]
In step 205, it is set that communication with unit F, unit S, unit R1, and unit R2 is impossible.
[0034]
In step 206, unit F, unit S, unit R1, and unit R2 detect an abnormality in unit M due to the failure of communication with unit M.
[0035]
In step 207, a hydraulic brake that supplies a master cylinder pressure generated by a driver's pedal operation to the front wheel braking means B1 and B2 is put into a state where it can be implemented. Since unit F receives pedal operation information S1 of SEN1 from unit S, normal brake-by-wire control may be performed based on S1.
[0036]
In step 208, a target braking force is calculated based on the electrical signals S1 and S2 of SEN1 and SEN3 input to the unit S, and a braking force command is transmitted to the units R1 and R2.
[0037]
In step 209, normal brake-by-wire control is performed on the rear wheel braking means B3 and B4.
[0038]
As described above, when an abnormality occurs in the unit M, the front wheel side performs a hydraulic brake by a driver's pedal operation or performs a brake-by-wire control based on the calculation in the unit F, and the rear wheel By performing brake-by-wire control on the side based on the calculation in the unit S, it is possible to achieve almost the same braking operation as normal operation.
[0039]
[Operation when unit S is abnormal]
FIG. 5 is a flowchart showing the operation when the unit S is abnormal.
In step 301, a microcomputer abnormality in the unit S is determined. If the microcomputer is abnormal, the process proceeds to step 304; otherwise, the control flow ends.
[0040]
In step 302, an abnormality of the power supply circuit is determined. When the power supply circuit is abnormal, the process proceeds to step 304 and step 306, and otherwise, the control flow ends.
[0041]
In step 303, it is determined whether the communication line is abnormal. If the communication line is abnormal, the process proceeds to step 305. Otherwise, the control flow ends.
[0042]
In step 304, the microcomputer in the unit S is stopped.
[0043]
In step 305, it is set that communication with unit M, unit R1, and unit R2 is impossible.
[0044]
In step 306, the normal values of the pedal operation information S1 and S3 are set to be undetectable.
[0045]
In step 307, the units R1 and R2 detect an abnormality of the unit S when communication with the unit S is not established.
[0046]
In step 308, the unit M diagnoses an abnormality in the pedal operation information S1 and S3. Alternatively, the unit S abnormality is detected when communication with the unit S is not established.
[0047]
In step 309, the target braking force is calculated from the pedal operation information S2 in the unit M, the braking force command is transmitted to the unit F, and the process proceeds to step 311.
[0048]
In step 310, the target braking force is calculated from the pedal operation information S2 in the unit M, a braking force command is transmitted to the units R1 and R2, and the process proceeds to step 312.
[0049]
In step 311, normal brake-by-wire control is performed on the front wheel braking means B1, B2.
[0050]
In step 312, normal brake-by-wire control is performed on the rear wheel braking means B3 and B4.
[0051]
That is, even if an abnormality occurs in the unit S, normal brake-by-wire control can be achieved based on the signal S2 of SEN2 input to the unit M.
[0052]
[Operation when unit F is abnormal]
FIG. 6 is a flowchart showing the operation of the unit F abnormality.
In step 401, a microcomputer abnormality in the unit F is determined. If the microcomputer is abnormal, the process proceeds to step 404; otherwise, the control flow is terminated.
[0053]
In step 402, an abnormality of the power supply circuit is determined. If the power supply circuit is abnormal, the process proceeds to step 404, and otherwise the control flow is terminated.
[0054]
In step 403, it is determined whether the communication line is abnormal. If the communication line is abnormal, the process proceeds to step 405. Otherwise, the control flow ends.
[0055]
In step 404, the microcomputer in the unit F is stopped.
[0056]
In step 405, it is set that control abnormality in the unit F and communication with the unit M are impossible.
[0057]
In step 406, the unit M detects an abnormality in the unit F due to the failure to establish communication with the unit F.
[0058]
In step 407, the unit M stops the brake-by-wire control on the front wheel side.
[0059]
In step 408, the unit M calculates a target braking force on the rear wheel side and transmits a braking command to the units R1 and R2.
[0060]
In step 409, a hydraulic brake that supplies a master cylinder pressure generated by the driver's pedal operation is made available for the front wheel braking means B1 and B2.
[0061]
In step 410, normal brake-by-wire control is performed on the rear wheel braking means B3 and B4.
[0062]
That is, even if an abnormality occurs in the unit F, the front wheel side can perform hydraulic braking by the driver's pedal operation, and the rear wheel side can achieve normal brake-by-wire control.
[0063]
As described above, in the brake control device according to the first embodiment, the unit F1 that performs hydraulic brake-by-wire control on the front wheel side and the unit R1, that performs electric brake-by-wire control on the rear wheel side is provided. R2 was provided. In particular, the front wheel side is configured such that the master cylinder pressure generated by the driver's pedal operation when the system is shut off can be supplied to the front wheel braking means B1 and B2.
[0064]
Therefore, even when the power supply system or supply line is lost and the system is shut down due to a failure state, the braking force can be reliably obtained by the hydraulic brake of the front wheels. In addition, since braking force can be obtained reliably in a failed state, there is no need to use more than two power supply systems and supply lines as a countermeasure against electrical system failures, eliminating the complexity of the system associated with redundant systems. The cost can be reduced (corresponding to claims 1 and 2).
[0065]
(Embodiment 2)
Next, a second embodiment will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described.
[0066]
FIG. 7 is a system diagram showing the overall configuration of the second embodiment. In the first embodiment, the brake generator 9 and the unit BG are provided. In the second embodiment, only the units R1 and R2, which are electric brake-by-wire control devices, are provided on the rear wheel side. .
[0067]
In the first embodiment, the braking command signal T2 is output to the units R1 and R2. However, in the second embodiment, a separate braking command signal (T2 is assigned to each unit R1). The unit R2 is different in that T5) is output. With this configuration, the braking force of the rear wheels can be controlled independently, and vehicle behavior control and the like can be executed.
[0068]
(Embodiment 3)
Next, Embodiment 3 will be described. In the third embodiment, the unit F that controls the front wheel braking means B1 and B2, the unit M that calculates the braking force based on various sensor values, the other unit O related to vehicle operation, and the rear wheel braking means B3 and B4. It is comprised from the unit R1, R2 which controls. The unit F is a hydraulic type, and even if the system is shut off when a failure occurs, the braking force can be generated by the driver's operation of the brake pedal, as in the other embodiments. .
[0069]
The brake pedal 1 is provided with three pedal sensors SEN1, SEN2, and SEN3. In the first and second embodiments, the pedal operation information of the driver is detected in the unit S, the output signals S1 and SEN3 of the SEN1 are converted into electrical signals, transmitted to the unit M, and the output signal S1 of the SEN2 Only was transmitted to the unit M and converted into electrical signals. On the other hand, in the third embodiment, the unit S is abolished and all output signals S1, S2, S3 are transmitted to the unit M.
[0070]
FIG. 9 is a block diagram illustrating an internal configuration of the unit M according to the third embodiment. In the unit M, a first control microcomputer M1 and a second control microcomputer M2 are provided. The first control microcomputer M1 and the second control microcomputer M2 perform transmission / reception of sensor signals and the like, and also monitor one failure mutually.
[0071]
Further, the power supply system E1 to the unit M branches into a P1 system and a P2 system inside the unit M. The power supply EP1 supplied from the P1 system is supplied to the first control microcomputer M1 and SEN1, SEN2. The power supply EP2 supplied from the P2 system is supplied to the second control microcomputer M2 and SEN3.
[0072]
Three pedal sensors SEN1, SEN2,. All the signals of SEN3 are transmitted to both the first control microcomputer M1 and the second control microcomputer M2.
[0073]
A front wheel control communication line T1 for outputting a braking command signal to the unit F is provided in the first control microcomputer M1. A communication line T3 with another vehicle unit that outputs a command signal to the unit O is provided in the second control microcomputer M2. A rear wheel control communication line T2 for outputting a braking command signal to the units R1 and R2 is provided in both the first control microcomputer M1 and the second control microcomputer M2.
[0074]
(Operation Based on Configuration of Embodiment 3)
The operation of each of the above configurations will be described.
[Configuration of first control microcomputer and second control microcomputer due to the abolition of unit S]
In the third embodiment, the configuration can be simplified by eliminating the unit S that converts the pedal sensor signal into an electric signal. At this time, as a countermeasure against the failure of the pedal sensor signal, the first control microcomputer M1 and the second control microcomputer M2 are provided in the unit M, and all the pedal sensor signals are transmitted to both control microcomputers. Therefore, even if a failure occurs in any one of the three pedal sensors, both control microcomputers can always receive other sensor signals.
[0075]
Further, even if a failure occurs in one of the first control microcomputer M1 and the second control microcomputer M2, the same sensor signal is input to the control microcomputer that has not failed, so that stable control is achieved. be able to.
[0076]
[Configuration of rear wheel control communication line T2]
For the units R1 and R2 that perform rear-wheel brake-by-wire control, which is an electric brake, a rear-wheel control communication line T2 is provided in both the first control microcomputer M1 and the second control microcomputer M2. That is, the units R1 and R2 are electric, and when a failure occurs in the electric system, the braking force cannot be generated. Therefore, by adopting a configuration in which a braking command signal can be output from both control microcomputers M1 and M2 to the rear wheels, a countermeasure against failure can be achieved, and the rear wheel braking force can be ensured.
[0077]
[Combined with P1 and P2 systems]
The power supply (P1 system) to the first control microcomputer M1 and SEN1, SEN2 and the power supply (P2 system) to the second control microcomputer M2 and SEN3 were set as separate systems. Therefore, even if a failure occurs in one of the power supply systems, it is possible to ensure the operation of one control microcomputer and at least one pedal sensor.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a system configuration of a brake control device according to a first embodiment.
FIG. 2 is a hydraulic circuit diagram showing a circuit configuration of a unit F in the first embodiment.
FIG. 3 is a flowchart showing an operation of the brake control device according to the first embodiment when the system is normal.
FIG. 4 is a flowchart showing the operation of the brake control device according to Embodiment 1 when unit M is abnormal.
FIG. 5 is a flowchart showing the operation of the brake control device according to Embodiment 1 when unit S is abnormal.
6 is a flowchart showing an operation when the unit F is abnormal in the brake control device according to Embodiment 1. FIG.
FIG. 7 is a block diagram showing a system configuration of a brake control device according to a second embodiment.
FIG. 8 is a block diagram illustrating a system configuration of a brake control device according to a third embodiment.
FIG. 9 is a block diagram showing the configuration of unit M in the third embodiment.
[Explanation of symbols]
1 Brake pedal 3 Master cylinder 4 Reservoir 62, 72 Pressure reducing valve 63, 73 Pressure increasing valve 64, 74 Piston 67, 77 Pump 68 Motor 69 Isolation valve WP1, WP2 Hydraulic pressure sensor

Claims (2)

This is a brake control device that includes two systems of a front wheel side and a rear wheel side, or two systems of diagonal wheels, and electrically controls at least one of each system to perform brake-by-wire control. And
Fail detection means for detecting the failure of each system;
When a failure is detected by the fail detecting means, fail safe control means for stopping the brake-by-wire control,
Even if the brake-by-wire control is stopped by the fail-safe control means, braking means for obtaining a braking force by at least one system;
A brake control device comprising: The brake control device according to claim 1, wherein
The brake control device is configured to have two systems, a front wheel side and a rear wheel side,
The braking means is a system on the front wheel side, is capable of executing brake-by-wire control, and is capable of pressurizing brake fluid in a wheel cylinder by a pedaling force of a driver's brake operation when a failure occurs. A brake control device characterized by being a device.

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