JPH0251786B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-skid control device for a vehicle, and in particular, when a signal from a stop switch is a signal indicating a non-braking state of the vehicle, the braking state of the vehicle is determined from the slip rate of the wheels. The present invention relates to an anti-skid control device that can accurately perform anti-skid control when a stop switch fails or is disconnected.

An anti-skid system for vehicles that automatically controls brake hydraulic pressure according to driving conditions to solve the problems of poor steering, impaired vehicle stability, and increased braking distance caused by wheels locking during vehicle braking. As one of the controls, a vehicle speed sensor is provided that generates a signal corresponding to the vehicle's wheel speed, and a stop switch is provided that is linked to the brake pedal and turns on when the driver operates the brakes. By determining whether or not the vehicle is in the braking state, it is detected that the vehicle is in the braking state, and at least when the braking state of the vehicle is detected, the slip rate of each wheel is determined to be the optimum slip rate based on the signal from the vehicle speed sensor. There is a system that controls the brake equipment installed on each wheel so that the

However, in this type of anti-skid control device, the stop switch is
Since the braking state of the vehicle is detected by determining the ON state, for example, if the stop switch malfunctions or breaks, the stop switch may not work even though the driver is operating the brakes. It is determined that the brake is in the OFF state, and the braking state of the vehicle cannot be detected. Therefore, even if the vehicle is in a state where anti-skid control should be performed, anti-skid control will not be performed.
In this case, the driver operates the brakes assuming that the anti-skid control device is working normally, so the wheels are more likely to lock, resulting in a more dangerous situation than in a vehicle not equipped with an anti-skid control device.

In addition, as a countermeasure to the above, it is also possible to install a stop switch abnormality detection circuit that detects stop switch failure or disconnection, and to display a warning lamp or the like to notify the driver of an abnormality in the anti-skid control device. It is being However, by providing the above-mentioned stop switch abnormality detection circuit, it is possible to notify the driver of an abnormality in the anti-skid control device.
In the end, anti-skid control could not be performed,
If the stop switch malfunctions while braking the vehicle,
If the wire breaks, it will be in a dangerous situation as described above. Therefore, an anti-skid control device provided with a stop switch abnormality detection circuit as described above only increases the cost and cannot be expected to be very effective.

In order to solve the above-mentioned problems, the present invention detects the braking state of the vehicle from the wheel slip rate when it is determined that the stop switch is in the OFF state, and detects the braking state of the vehicle from the wheel slip rate. It is an object of the present invention to provide an anti-skid control device capable of performing good anti-skid control.

The structure of the present invention to achieve this purpose is the first
As shown in the figure, it is equipped with a vehicle speed sensor that generates a signal corresponding to the wheel speed of the vehicle, and a stop switch that is linked to the brake pedal and detects the driver's brake operation, and at least based on the signal from the stop switch. a brake determining means for determining a braking state of the vehicle; and at least after the braking determining means determines that the vehicle is in a braking state, the brake is adapted to a vehicle running state determined based on a signal from the vehicle speed sensor. In an anti-skid control device equipped with an electronic control circuit that generates a hydraulic control signal, when a signal indicating a non-braking state of the vehicle is input from the stop switch to the braking determination means, the braking determination means is determined based on the signal from the vehicle speed sensor. The vehicle is judged to be in a braking state when the slip rate of the wheels is greater than the predetermined slip rate. The gist of the present invention is an anti-skid control device characterized in that it is provided with comparison means for comparing the skids.

In this way, in the anti-skid control device of the present invention, the braking determining means is provided with a comparing means, and when a signal indicating a non-braking state of the vehicle is inputted from the stop switch, the comparing means performs a determination based on a signal from the vehicle speed sensor. A comparison is made between the slip rate of the wheels and a predetermined slip rate set to determine the braking state, and if the slip ratio of the wheels is greater than the predetermined slip ratio, it is determined that the vehicle is in the braking state. . Therefore, even if the stop switch malfunctions or the signal line from the stop switch to the braking determination means is disconnected, and the braking determination means cannot determine the braking state of the vehicle based on the signal from the stop switch, the comparing means can detect the vehicle's braking condition. It becomes possible to determine the braking state.

In the present invention, when the stop switch outputs a signal indicating the braking state of the vehicle in the braking determining means, the comparing means does not operate, and the braking state of the vehicle is determined based on the signal from the stop switch. That is, in the present invention, the braking state of the vehicle is mainly determined based on the signal representing the braking state of the vehicle output from the stop switch, and only when the stop switch is not outputting a signal representing the braking state of the vehicle, wheel slippage is determined. This is done by comparing the slip rate with a predetermined slip rate. The reason for this will be explained below.

First, if a stop switch is not provided and the braking state of the vehicle is determined based only on the slip rate of the wheels, erroneous determination may occur under various driving conditions. For example, when driving on a rough road, vibrations in the suspension system may cause the wheel speed output from the vehicle speed sensor to become unstable, resulting in a signal that appears as if slipping has occurred.
In this case, if the anti-skid control is performed without depending on the depression of the brake pedal, the driver may feel uncomfortable due to malfunction, and there may be problems with the durability of the actuator. Therefore, when determining the braking state from the slip rate of the wheels, it is desirable to set a relatively large reference slip ratio for determining the braking state in order to prevent such erroneous determination.

However, if this reference slip ratio is set to a large value, it becomes impossible to promptly detect the braking state, and the responsiveness of the anti-skid control is reduced. That is, when determining the braking state of a vehicle based only on the slip rate of the wheels, it is difficult to set a reference slip rate that will quickly and accurately determine the braking state under various driving conditions.

Therefore, in the present invention, the braking state is normally determined by the stop switch, and in the event that the stop switch fails, the braking state of the vehicle is determined based on the slip rate of the wheels and anti-skid control is executed. -ing As a result, according to the present invention, even if the stop switch fails, anti-skid control can be reliably executed when braking is actually performed and the slip rate increases, that is, when anti-skid control is highly necessary. This makes it possible to improve the safety and reliability of the anti-skid control device.

Next, the present invention will be described with reference to examples and drawings.

FIG. 2 is a system diagram schematically showing the overall configuration of an anti-skid control device installed in a rear-wheel drive vehicle.

In the figure, 1 to 4 represent each wheel of the vehicle; 1 is the right front wheel, 2 is the left front wheel, 3 is the right rear wheel, and 4 is the left rear wheel. Numerals 5 to 7 are electromagnetic pickup type or photoelectric conversion type vehicle speed sensors for detecting the wheel speed, respectively. Of these, 5 is attached near the right front wheel 1, and
A right front wheel speed sensor 6 is installed near the left front wheel 2 and generates a signal according to the rotation of the left front wheel 2.
A left front wheel vehicle speed sensor 7 that generates a signal according to the rotation of the vehicle is attached to a propeller shaft 8 that transmits power to the right rear wheel 3 and the left rear wheel 4, which are drive wheels.
This is a rear wheel speed sensor that generates a signal in accordance with the rotation of the propeller shaft 8 corresponding to the average rotational speed of the right rear wheel 3 and the left rear wheel 4. 9 to 12 are hydraulic brake devices, respectively, where the hydraulic brake device 9 is attached to the right front wheel 1, the hydraulic brake device 10 is attached to the left front wheel 2,
The hydraulic brake device 11 is installed on the right rear wheel, and the hydraulic brake device 12 is installed on the left rear wheel 4.
13 is a brake pedal, 13S is linked to the brake pedal 13, and is activated by the driver's brake operation.
Stop switch that turns ON/OFF, 14 is parking brake, 14S is parking brake 1
Parking switch linked to 4 and turned on/off by the driver's parking brake operation, 15
16 represents a hydraulic cylinder that generates brake hydraulic pressure when the brake pedal 13 is depressed, and a hydraulic pump that generates hydraulic pressure in response to engine rotation.
17 to 19 are actuators that adjust the hydraulic pressure from the hydraulic cylinder 15 and the hydraulic pump 16 according to the output from an electronic control circuit 26 (described later) and send it to the hydraulic brake devices 9 to 12;
7 is a right front wheel actuator corresponding to the hydraulic brake device 9 of the right front wheel 1; 18 is a left front wheel actuator corresponding to the hydraulic brake device 10 of the left front wheel 2;
19 is a hydraulic brake device 11, 12 for the rear wheels 3, 4
This is a rear wheel actuator that corresponds to the following. 20 to 23 are hydraulic pipes for guiding the adjusted hydraulic pressure from the actuators 17 to 19 to the hydraulic brake devices 9 to 12; of these, 20 is a line between the right front wheel actuator 17 and the hydraulic brake device 9 of the right front wheel 1; 21 is a hydraulic pipe provided between the left front wheel actuator 18 and the hydraulic brake device 10 for the left front wheel 2; 22 is a hydraulic pipe provided between the rear wheel actuator 19 and the hydraulic brake device 11 for the right rear wheel 3; 23 represents a hydraulic pipe line provided between the rear wheel actuator 19 and the hydraulic brake device 12 of the left rear wheel 4. 24
is a main relay that switches the connection between the electromagnetic solenoids of the actuators 17 to 19 and the power supply source according to the output of the electronic control circuit 26;
25 is for notifying the driver that an abnormality has occurred in the system according to the output of the electronic control circuit 26 when a failure occurs in the anti-skid control device, such as when the electromagnetic solenoid is disconnected or when the vehicle speed sensors 5, 6, and 7 are disconnected. indicates the indicator lamp. 26
is an electronic control circuit, and vehicle speed sensors 5 to 7,
and receiving a signal from the stop switch 13S,
This represents a device that performs arithmetic processing for anti-skid control and generates outputs that control the actuators 17 to 19, the main relay 24, and the indicator lamp 25.

The right front wheel actuator 17, left front wheel actuator 18, and rear wheel actuator 19 are each connected to a hydraulic pump 16
Regulator part 2 that adjusts the hydraulic pressure from
7, a control valve section 28 including an electromagnetic solenoid for increasing/decreasing control for switching the increase/decrease direction of brake oil pressure, and an electromagnetic solenoid for slow/sudden control for switching the gradient of increase/decrease of brake oil pressure into two stages, slow and fast. The hydraulic pressure adjustment unit 29 includes a brake hydraulic pressure adjustment unit 29, and the hydraulic pressure output from each actuator is applied to the brake and hydraulic pressure of each hydraulic brake device via each hydraulic pipe line.
The signal is transmitted to the wheel cylinders and brakes are applied to each wheel. In addition, the electromagnetic solenoid for increase/decrease control decreases the hydraulic pressure when energized, and
For example, the electromagnetic solenoid for sudden control is designed to have a steep increase/decrease gradient when energized.

The above electronic control circuit 26 has a circuit configuration as shown in FIG. A pulse signal suitable for
The other waveform shaping amplifier circuits 31 and 32 are also configured to generate similar pulse signals. 33a
and 33b are buffer circuits electrically connected to the stop switch 13S and the parking switch 14S, respectively, and 34 is an ignition switch 41.
A power supply circuit for supplying constant voltage to the microcomputer 35 etc. when turned on, 35 is a CPU 35a,
ROM35b, RAM35c, I/O circuit 35d
It represents a microcomputer equipped with etc. 3
6 to 40 are each microcomputer 3
Of these, 36 is a right front wheel actuator drive circuit for driving the electromagnetic solenoid of the right front wheel actuator 17, and 37 is a drive circuit for driving the electromagnetic solenoid of the left front wheel actuator 18. 38 is a rear wheel actuator drive circuit for driving the electromagnetic solenoid of the rear wheel actuator 19; 39 is a normally open contact 24;
The main relay drive circuit 40 energizes the coil 24b of the main relay 24 having the reference numeral a to turn on the normally open contact 24a, and the reference numeral 40 represents an indicator lamp drive circuit for lighting the indicator lamp 25.

Next, the processing and operation of the anti-skid control device configured as described above will be explained.

When the ignition switch 41 is turned on,
A constant voltage from the power supply circuit 34 is applied to the microcomputer 35 etc.
The CPU 35a of No. 5 starts executing arithmetic processing according to a program preset in the ROM 35b.

FIG. 5 is a schematic float chart showing the main part of this arithmetic processing. In this processing, first, only at the start of processing, initialization processing for subsequent processing is performed, for example, setting of various flags to be described later. Perform a reset, etc.

Thereafter, steps 102 and 103 are performed depending on the determination result at step 107.
A series of processes consisting of step 104, step 105, step 106, and step 107,
Alternatively, step 102, step 103, step 104, step 105, and step 106
and step 107 and step 108 and step 1
09 is repeatedly executed until the ignition switch 41 is turned off.

In this series of processing, step 102
A control permission determination process and a control start determination process are executed. That is, when calculating the estimated vehicle speed in estimated vehicle speed calculation processing step 104, which will be described later,
In addition to setting and resetting the permission flag Fact for instructing to change the selection of the wheel speed that is one of the plurality of estimated vehicle speed candidates, it also instructs to change the processing content of the traveling route determination processing step 103, which will be described later. Actuate pattern selection step 20 in the timer interrupt routine
6, etc., and a start flag for instructing the selection of a reference speed to be calculated in step 105 of the reference speed calculation processing described later.
Performs Fsta set/reset processing.

Next, in step 103, the type of road on which the vehicle is currently traveling, the coefficient of friction based on the road surface condition, and the unevenness of the road surface are estimated, and the vehicle is estimated to be on a high friction road such as a dry concrete road or a wet road. It is either a medium μ road such as asphalt, or a low μ road such as an icy road, a so-called good road with a very gentle degree of unevenness, a so-called bad road with a certain degree of roughness, or a very rough road. A driving route determination process is executed to determine the nature of the road itself, such as a so-called extremely bad road (including a wavy road), which is likely to cause problems for anti-skid control, according to specific conditions. To roughly describe the content of this discrimination process, the corresponding wheel speed Vw data calculated based on the signals from the individual vehicle speed sensors 5, 6, and 7 (however, for the rear wheel speed, the right rear wheel 3 This corresponds to the average wheel speed of the actual wheel speed and the actual wheel speed of the left rear wheel 4), wheel acceleration Vw data, multiple levels of reference acceleration data stored in advance in the ROM 35b, and reference speed. Based on the plurality of reference speed data calculated in calculation processing step 105, processing corresponding to size comparisons of various combinations of wheel speed, wheel acceleration, and reference speed and reference acceleration is performed for each individual wheel. At the same time, the value of the counter, which is incremented or decremented according to the processing result, is compared in magnitude with a predetermined set value, and the travel route is finally determined based on the comparison result.

Next, in step 104, estimated vehicle speed calculation processing is executed. To give an overview of this process, when creating estimated vehicle speed data, there are three candidate speeds: the calculated wheel speed and the driving acceleration that can be obtained from the actual vehicle driving state (including during braking). The intermediate value of the upper and lower limit values, and the first and second estimated vehicle speeds calculated using two calculation formulas based on the estimated vehicle speed calculated in the previous estimated vehicle speed calculation process, etc. is determined as the estimated vehicle speed. In this case, the wheel speed, which is one of the candidate speeds, is the intermediate value of the three wheel speeds during the period in which the permission flag Fact is in the reset state as described above in the control permission/start determination processing step 102. On the other hand, during the period when the permission flag Fact is set, the wheel speed that takes the maximum value is selected as a candidate.

Next, in step 105, a reference speed calculation process is executed. The outline of this process is that until the start flag Fsta is reversed from the reset state to set, that is, until the start of depressurization (which can also be called the start of control), a control start judgment reference speed is calculated, and the start flag Fsta is After the setting, that is, after the start of control, the standard speed for road noise (vehicle body vibration) countermeasures to prevent malfunction of the actuators 17 to 19 due to road noise, electrical noise, etc., and the depressurization, which is one of the standards for starting depressurization. The data corresponding to the judgment reference speed, the intermediate μ judgment reference speed which is a reference for determining an intermediate μ road, and the low μ judgment reference speed which is a reference for determining a low μ road are at least estimated vehicle speed. It is created from a predetermined arithmetic expression including: Note that the control start determination reference speed is set in step 103 of the traveling route determination process in order to prevent at least one of the actuators 17 to 19 from starting an undesired pressure reduction due to slow braking, especially on a rough road. The value of the subtracted number in the arithmetic expression is made variable according to the characteristics of the road itself determined in . In addition, for the road noise (vehicle body vibration) countermeasure standard speed and decompression judgment standard speed, the value of the subtracted number in the corresponding calculation formula is variable, and the decompression speed can be changed depending on the rough road condition. This prevents excessive depressurization due to overcontrol.

Next, in step 106, a system abnormality check is executed. In this process, the ROM35b
Compare and examine the data corresponding to the operating state of the system element during normal system operation stored in advance with the data representing the operating state of the system element captured during the processing, and if it is determined that the system is abnormal. An abnormality flag indicating the system operating state is set, and if it is determined that there is no abnormality, the abnormality flag is maintained in a reset state or reversed.

Next, in step 107, the abnormality flag is checked to determine whether or not there is a system abnormality. If it is determined that the abnormality flag is not set, that is, if the system is operating normally, the process proceeds to step 102 of the control permission and start determination process as described above. On the other hand, if it is determined that the abnormality flag is set, that is, if an abnormality has occurred in the system or the system is operating abnormally, steps 108 and 109 are sequentially executed, and the control permission and start determination described above are performed. Proceed to processing step 102.

Step 108 is a step for notifying the driver that an abnormality has occurred in the system so that he can confirm that the anti-skid control is not effective. Only when it is determined for the first time that the above occurs, a control signal for lighting the indicator lamp is output to the indicator lamp drive circuit 40. Indicator lamp drive circuit 40, which receives this control signal, latches this control signal so that indicator lamp 25 continues to be lit. This step 108 also includes a process of outputting a control signal to the indicator lamp drive circuit 40 to turn off the indicator lamp 25 when the system automatically returns to the normal operating state after outputting the control signal as described above. It may also be executed by

Step 109 is a step for performing fail-safe processing in the event of abnormal system operation.
7, 18, and 19, regardless of the driving state of the electromagnetic solenoid for increase/decrease control and the electromagnetic solenoid for slow/sudden control at that time, the non-antiskid control mode, that is, the brake oil pressure according to the depression of the brake pedal 13. In order to switch to the normal mode in which braking is performed by the main relay 24, a process is performed to output a control signal to cut off the energization to the coil 24b of the main relay 24. When the coil 24b is no longer energized, the previously closed normally open contact 24a is switched to its normally open state, thereby cutting off the power supply to the electromagnetic solenoids in each of the actuators 17, 18, 19, and at least Normal braking is performed until the system abnormality is resolved. In this system fail-safe processing step 109, in order to further improve safety, the power supply is cut off as described above, and a control signal is output to each actuator drive circuit 36, 37, 38 to turn off the electromagnetic solenoid. It is also possible to perform the following processing at the same time.

FIG. 6 is a flowchart schematically showing a timer interrupt routine that is started to be executed at a predetermined cycle during execution of the main arithmetic processing as described above in FIG.

In this timer interrupt routine, first, in step 201, a process of calculating the wheel speed of each wheel is executed. This wheel speed calculation step 20
1, a predetermined arithmetic expression is calculated that includes the difference between the count value of vehicle speed pulses during the current process execution and the count value of vehicle speed pulses during the previous process execution, a time interval, and a constant. At the same time, if necessary, a filter device, that is, a process of averaging the wheel speeds obtained by a plurality of consecutive calculations of the arithmetic expression is also performed. Note that the counting of the vehicle speed pulses is executed in a vehicle speed interrupt routine to be described later.

Next, in step 202, processing for calculating wheel acceleration for each wheel is executed. This wheel acceleration calculation step 202 includes the speed difference between the wheel speed calculated by executing the wheel speed calculation step 201 and the wheel speed calculated by the previous wheel speed calculation step 201, time, and a constant. In addition to calculating a predetermined arithmetic expression, processing substantially similar to that of the filter device described above is also performed as necessary.

Next, in step 203, it is determined whether or not the permission flag Fact described above in FIG. is set, the route consisting of steps 205 to 208 is executed sequentially.

In step 204 above, the permission flag
During the first process after resetting Fact, a process is performed in which a control signal for this purpose is output to each of the actuator drive circuits 36, 37, 38 in order to return all the actuators 17, 18, 19 to a non-operating state. Each of the actuator drive circuits 36, 37, and 38 to which this control signal is input maintains a state corresponding to this control signal, stops energizing the electromagnetic solenoid of the corresponding actuator, and brake hydraulic pressure control is performed in the normal mode. Make it. Note that the above output processing does not need to be performed in the second and subsequent processing after the permission flag Fact is reset. After passing through this output step 204, normally the process shown in FIG. 5, which has been interrupted, continues to be executed.

On the other hand, in step 205 executed when the permission flag Fact is set, each wheel speed and each wheel acceleration calculated in the wheel speed calculation step 201 and the wheel acceleration calculation step 202, and the reference speed calculation in FIG. A process of comparing various reference speeds calculated in processing step 105 with various preset reference accelerations is executed.

Next, in step 206, the comparison step 2 is performed.
Based on the results obtained in step 05, a process is executed to select a drive pattern for each of the increase/decrease control electromagnetic solenoid and the slow/sudden control electromagnetic solenoid. Note that various drive patterns corresponding to each solenoid are stored in advance in the ROM 35b.

Next, in step 207, the pressure increase mode and the continuous time of the pressure increase mode are monitored, and if the pressure decrease mode continues for a time that is predicted to be impossible based on normal anti-skid control, a permission flag is set. In order to determine that there is a system abnormality even if Fact is being set, and force all actuators 17, 18, and 19 to be inactive in the next step 208, the actuator pattern selection step 206 is selected. A process for changing the drive pattern is executed.

Next, in step 208, a process is executed to output a control signal corresponding to the final drive pattern to the corresponding actuator drive circuits 36, 37, and 38. The actuator drive circuits 36, 37, and 38 to which this control signal has been input respectively drive the corresponding actuator 1 according to this control signal.
A drive output is performed to determine the drive state of 7, 18, and 19. After passing through this output step 208, the process shown in FIG. 5, which has been interrupted, is normally continued.

Figure 7 shows one for each of vehicle speed sensors 5, 6, and 7.
This is a vehicle speed interrupt routine that is executed in correspondence with the vehicle speed sensor and waveform shaping amplifier circuit, and this vehicle speed interrupt routine is executed as shown in FIG. The process is interrupted and execution is started. In this case, it goes without saying that priority is given in advance to the three vehicle speed interrupt routines in consideration of the case where interrupt instructions are generated simultaneously by two or more vehicle speed pulses.

In this vehicle speed interrupt routine, step 3
01 is executed and vehicle speed pulses are counted. Note that this count value is calculated at wheel speed calculation step 20 in the timer interrupt routine as described above.
It is often used in the execution of 1.

Next, the operation of each part controlled by the above-described processing will be briefly explained using FIG. 8, taking the right front wheel 1 as an example.

Fig. 5 assumes that when braking is started, the wheel speed Vwr of the right front wheel 1 first decreases, then the wheel speed Vwl of the left front wheel 2, and the wheel speed Vwt of the rear wheels 3 and 4. Each wheel speed Vwt, Vwr, Vwl,
The acceleration V〓wr of the right front wheel 1, the operating status of the electromagnetic solenoid for increase/decrease control of the right front wheel actuator 17, the electromagnetic solenoid for slow/sudden control of the right front wheel actuator 17, and the output from the right front wheel actuator 17. This figure shows the relationship between brake oil pressure.

In the figure, V ₀ is the actual vehicle speed, Vss, Vsn,
Vsh is the estimated vehicle speed at step 105 in Figure 7.
Various standard speeds calculated based on Vsb,
Vss is the control start judgment reference speed, Vsn is the road noise countermeasure reference speed, Vsh is the decompression judgment reference speed,
In this case, the control start determination reference speed Vss and the depressurization determination reference speed Vsh are determined from the estimated vehicle speed Vsb with the same speed difference ΔV. Further, G ₁ , G ₂ , and G ₃ are reference acceleration data stored in advance in the ROM 35 as described above.

First, when the driver performs a brake operation at time t ₀ and the vehicle starts braking, the right front wheel speed changes.
The anti-skid control starts at time _t1 when Vwr becomes smaller than the control start judgment reference speed Vss, and the electromagnetic solenoid for increase/decrease control and the electromagnetic solenoid for slow/sudden control are turned on (at the same time), and the brake Hydraulic pressure is suddenly reduced.

When the brake hydraulic pressure is suddenly reduced from time t ₁ and the brake is released, the decrease in wheel speed Vwr slows down and the wheel speed Vwr begins to increase, and at time t ₂ , when the reference acceleration G exceeds ₁ , it is used for slow/sudden control. Only the electromagnetic solenoid is turned off, and the brake oil pressure is slowly reduced. Then, when the wheel acceleration V〓wr further increases and reaches a value larger than the reference acceleration _G2 at time _t3 , the electromagnetic solenoid for increase/decrease control is turned off, and the brake oil pressure is gradually increased. Even when the brake oil pressure is gradually increased, the wheel acceleration V〓wr continues to rise until it becomes larger than the reference acceleration _G3 at time t ₄ , and again becomes smaller than the wheel acceleration V〓wr until time t ₅ . The electromagnetic solenoid for slow/sudden control is turned on, and the brake oil pressure increases rapidly. When the wheel acceleration begins to decrease after time _t5 , the electromagnetic solenoid for slow/sudden control is turned off again, and the wheel speed Vwr becomes lower than the road noise countermeasure reference speed Vsn at time _t6.
The brake hydraulic pressure is gradually increased until time t ₆ , and the electromagnetic solenoid for increase/decrease control is ON until time t ₇ when the wheel speed Vwr becomes equal to or less than the pressure reduction judgment reference speed Vsh after time t 6.
The brake oil pressure is gradually reduced. Then, the wheel speed Vwr again reaches the decompression judgment reference speed at time _t7 .
When the voltage drops below Vsh, the electromagnetic solenoid for slow/sudden control is turned on, and the brake hydraulic pressure is suddenly reduced.Then, the same control as described above is performed, and at time _t8 , the electromagnetic solenoid for slow/sudden control is turned off, and at time t. At time _{t 9} , the electromagnetic solenoid for increase/decrease control is OFF, at time t ₁₀ , the electromagnetic solenoid for slow/sudden control is ON, at time t ₁₁ , the electromagnetic solenoid for slow/sudden control is OFF, etc., and the brake hydraulic pressure is The pressure decreases slowly → slowly increases → rapidly increases → slowly increases, and so on.

In this way, the brake oil pressure is controlled for each wheel speed Vwt, Vwr, Vwl, and each wheel 1, 2,
Hydraulic brake devices 9, 10 provided at 3, 4,
By controlling 11 and 12, wheel lock can be prevented and the vehicle can be stopped within a short braking distance.

The processing operations of the present anti-skid control device have been briefly explained below, and next, the main processing of the present invention will be explained in detail according to the flowchart shown in FIG. In addition, FIG. 9 shows the control permission shown in FIG.
This represents the control permission determination process in step 102 of the start determination process, and as described above, when the stop switch 13S is broken or disconnected, control permission is determined by determining the driver's brake operation from the wheel slip rate. It is about making a judgment.

When the ignition switch 41 is turned on and the main control permission determination process is executed for the first time,
First, in step 401, it is determined whether the estimated vehicle speed Vsb obtained in estimated vehicle speed calculation step 104 in FIG. Since it has just been turned on and Vsb has been set to 0 in the initialization process step 101 in FIG. .

When the process of step 402 is executed, a flag is set.
Fact will be determined to be "0", but at this point, since it has just been set to Fact = 0 in the initialization process step 101 of FIG. 5, as described above, the value of "0" is This is maintained as it is, and the main control permission determination process ends, and the process moves to the subsequent control start determination process (not shown). In this way, the series of processes in which the main control permission determination process is completed with only steps 401 and 402 are performed until the vehicle starts running and the estimated vehicle speed Vsh is 0 [Km/h].
This can be continued until the above is reached.

Next, the main control permission determination process while the vehicle is running will be described. First, in step 401, since the estimated vehicle speed Vsh is greater than 0 [Km/h], the determination is ``YES'', and the process moves to the following step 403.

In step 403, it is determined whether or not the stop switch 13S is in the OFF state, and if the stop switch 13S is in the ON state, the process proceeds to step 40.
4, and in step 404, the flag Fbs is set to "0". Here, the flag Fbs is a flag indicating that the driver operated the brake when the stop switch 13S is out of order (or disconnected). In this case, since the stop switch 13S is in the ON state, the stop switch 13S is activated. Determined to be normal and flagged
The FBS is put into a reset state.

On the other hand, if it is determined in step 403 that the stop switch 13S is in the OFF state, the process moves to the subsequent step 405, where it is determined whether the flag Fbs is "0". If we proceed with the discussion assuming that Fbs=0 at this point, it will be determined as "YES" in step 405.
The process moves to the next step 406.

In step 406, it is determined whether or not the parking switch 14S is in the OFF state, and if the parking switch 14S is in the OFF state, it is determined as "YES" in this step 406,
The process moves to the next step 407, and if the parking switch 14S is in the ON state and the determination is "NO", the process moves to step 408. Normally, the parking brake 14 is operated while the vehicle is running, and the parking switch 14S is rarely turned on.If the determination is ``YES'' here, the process of step 407 is executed.

In step 407, it is determined whether the vehicle speed sensors are normal or not, that is, each vehicle speed sensor 5, which is counted in the vehicle speed interrupt routine shown in FIG.
It is determined whether the signals from 6 and 7 are reliable. If there is an abnormality in the vehicle speed sensor, the answer at step 407 is "NO".
If it is determined that the vehicle speed sensor is normal and the result is ``YES'', the process proceeds to step 409, where a slip rate calculation process is executed.

The slip rate calculation process performed in step 409 refers to the estimated vehicle speed Vsb obtained in the estimated vehicle speed calculation step 104 shown in FIG.
Based on the wheel speed Vw of each wheel determined in the wheel speed calculation step 201 of FIG. Therefore, when the slip rate μw of each wheel is calculated in step 409, the next step 410 is executed.

In step 410, the step 40
It is determined whether any one of the slip ratios μw of each wheel found in step 9 exceeds 30%. Here, if the slip ratio μw of each wheel is all 30% or less, the determination is "NO" and the process moves to step 408. On the other hand, if any one of the slip ratios μw of each wheel exceeds 30%. If there is one, it will be judged as “YES” and the process will proceed to step 4.
11, and the value of the flag Fbs is set to "1".

As described above, the flag Fbs is a flag that is set by detecting the driver's brake operation when the brake switch 13S fails (or breaks), and in this embodiment, steps 401, 403, 405, Step 406,
“YES” in a series of determination processes in step 407
It is determined that step 4 is the key point of the present invention.
09 and step 410, the flag Fbs is set to "1" only when the driver's brake operation is detected from the wheel slip rate. Also, the value of 30% in step 410 is
For example, it is 30%, and is not limited.

The above process describes the process when the stop switch 13S is in the OFF state and the value of the flag Fbs is "0" while the vehicle is running.
Next, the stop switch 13S is activated while the vehicle is running.
To explain the processing when it is in the OFF state and the value of the flag Fbs is set to "1", first, "YES" is selected in step 401, and step 403 is set.
``YES'' is determined, and the process of step 405 is executed.

In step 405, since the flag Fbs is "1", the determination is "NO", and the process moves to step 412.

In step 412, all actuator drive signals output in step 208 of the timer interrupt routine shown in FIG. 6 are turned off for 2 seconds or more.
state or not, that is, all actuators are 2
It is determined whether the pressure is in a state of gradual pressure increase for more than seconds.

If it is determined in step 412 that all actuator drive signals are in the OFF state for 2 seconds or more, it is determined that the anti-skid control has ended, that is, the driver has not operated the brakes, and the flag Fbs is set in step 404. is set to "0".

On the other hand, in step 412, if all actuator drive signals are not in the OFF state, or if more than 2 seconds have not elapsed since they were in the OFF state, the driver's brake operation is continuing and anti-skid control is in progress. It is determined that this is the case, and the process moves to step 408.

The process explained above is a process for setting or resetting the flag Fbs, and then a flag indicating control permission is set based on the value of this flag Fbs.
The process of setting/resetting facts will be explained.

If Fbs=1 in step 411, Fbs=0 in step 404, or in step 406, step 407, or step 4.
10. In the process of step 408, which is executed when the determination is "NO" in any of the processes of step 412, the stop switch 13S is turned OFF, as in the process of step 403.
It is determined whether the state is the same or not.

If the stop switch 13S is in the OFF state, "YES" is determined in step 408, and the flag Fbs is set to "1" in the following step 413.
It is determined whether or not. Here, flag Fbs
If the flag is 0, the determination in step 413 is "NO", the flag Fact is set to "0" in step 402, and the control permission process is ended.

On the other hand, if the stop switch 13S is in the "ON" state and it is determined as "NO" in step 408, or if the flag Fbs is "1" and it is determined as "YES" in step 4013, step 414 is performed. The process is executed and step 41
In step 4, whether or not the system of the anti-skid control device is normal, that is, in step 106, similar to the process in step 107 shown in FIG.
By looking at the abnormality flag set in , it is determined whether the system is normal or not.

When it is determined in step 414 that the system is normal, the process moves to the following step 415, where the flag Fact is set to "1" and the control permission determination process is ended. On the other hand, step 41
If it is determined in step 4 that the system is abnormal, step 402 is executed and the flag Fact is set to "0".
Then, this control permission determination process ends.

In this way, if the stop switch 13S is in the ON state and the system of this anti-skid control device is normal, or if the stop switch 13S is in the ON state,
Even if the anti-skid control device is in the OFF state, the flag Fbs is set to “1” and the system of this anti-skid control device is normal, Step 41 is executed for the first time.
By the process in step 5, the flag Fact is set to "1", and anti-skid control is permitted.

According to the anti-skid control device of this embodiment, the stop switch 13S is activated by the above-described process.
Not only when is in ON state, but also when stop switch 13S is in OFF state,
Parking switch 14S is in the OFF state,
If the vehicle speed sensor is normal, the driver's brake operation, that is, the braking state of the vehicle, can be detected from the slip rate μw of each wheel, and the stop switch 1
Even if the 3S is out of order (or disconnected), the flag Fact indicating anti-skid control permission can be set to "1". Therefore, even when the stop switch 13S is out of order (or disconnected), good anti-skid control can be performed depending on the vehicle running condition.

In this embodiment, the determination processing in steps 406 and 407 is provided between the time when it is determined in step 403 that the stop switch 13S is in the OFF state and the time when the slip rate calculation processing step 409 is executed. This is for the reason explained below.

First, step 406, parking switch 14
The process of determining whether or not S is in the OFF state is that the parking switch 14S is intentionally turned on by the driver while the vehicle is running;
It is thought that the driver himself is expecting the wheels to lock, etc., and braking of the vehicle by operating the parking brake 14 is different from braking by operating the brake pedal 13, and is independent of the oil pressure of the hydraulic brake system. Since the brakes are applied mechanically, wheel lock cannot be prevented even if the brake hydraulic pressure is controlled by anti-skid control. Therefore, if the parking switch 14S is in the ON state, it is decided to directly proceed to step 408. be.

In addition, the process of determining whether the vehicle speed sensor is normal in step 407 is performed when the signal from one vehicle speed sensor is abnormal, for example, if the signal is not received due to a disconnection, or if the signal is not received from another vehicle speed sensor due to a sensor failure. If the number of pulses is significantly lower than the traffic signal, the wheel slip rate will exceed 30%, and the flag Fbs will be set to "1" even if the driver is not applying the brakes. Therefore, if the vehicle speed sensor is abnormal, it is decided to directly proceed to step 408.

Furthermore, in step 412, the process of determining whether or not all actuator drive signals are in the OFF state for 2 seconds or more is performed by detecting that the brake operation by the driver has been completed and setting the flag Fbs to "0". '', but 2 seconds in this case is similar to 30% in step 410, for example, 2 seconds, and is not limiting.

As detailed above, the anti-skid control device of the present invention, when the stop switch is malfunctioning or disconnected and the driver's brake operation is not detected by the signal from the stop switch,
By determining whether the slip rate of the wheels is greater than or equal to a set value, it is possible to detect the driver's brake operation in the event of a stop switch failure or disconnection. Therefore, according to the anti-skid control device of the present invention, it is possible to constantly detect the driver's brake operation, and good anti-skid control can be performed even when the stop switch is broken or disconnected, resulting in safer anti-skid control. It becomes a control device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIGS. 2 to 9 show an embodiment of the present invention.
FIG. 2 is a schematic system diagram showing the overall structure of the anti-skid control device of this embodiment, and FIG. 3 is a block diagram showing the main structure of the actuators 17 to 19 that send brake oil pressure to each wheel in FIG.
4 is a block diagram showing the circuit configuration of the electronic control circuit 26 in FIG. 2, FIG. 5 is a flowchart showing the main arithmetic processing of the microcomputer 35 shown in FIG. 7 is a flowchart showing a vehicle speed interrupt routine that is also processed by the microcomputer 35. FIG. 8 is a flowchart showing the operation waveforms of each part of the anti-skid control device. FIG. 9 is a flowchart showing the control permission determination processing performed at step 102 shown in FIG. 5, which is the key point of the present invention. ...Vehicle speed sensor, 13S...Stop switch, ...Brake judgment means, ...Brake oil pressure control signal, ...Electronic control circuit, ...Comparison means, 5...Right front wheel speed sensor, 6...Left front wheel speed sensor , 7... Rear wheel speed sensor, 9, 10, 1
1, 12... Hydraulic brake device, 13... Brake pedal, 14... Parking brake, 14S
... Parking switch, 17 ... Right front wheel actuator, 18 ... Left front wheel actuator, 19
...Rear wheel actuator, 35...Microcomputer, 35a...CPU, 35b...ROM,
35c...RAM, 35d...I/O circuit.

Claims (1)

[Scope of Claims] 1. A vehicle speed sensor that generates a signal corresponding to the wheel speed of the vehicle, a stop switch that is linked to a brake pedal and detects a driver's brake operation, and at least a signal from the stop switch. and a braking determination means for determining the braking state of the vehicle based on the braking state of the vehicle, and at least after the braking determining means determines that the vehicle is in the braking state, the vehicle travel state is determined based on the signal from the vehicle speed sensor. In an anti-skid control device including an electronic control circuit that generates a brake oil pressure control signal, when a signal indicating a non-braking state of the vehicle is inputted to the braking determination means from the stop switch, the braking determination means determines whether the braking is performed based on the signal from the vehicle speed sensor. A comparison is made between the required slip ratio of the wheels and a predetermined slip ratio set to determine the braking state, and if the slip ratio of the wheels is greater than the predetermined slip ratio, it is determined that the vehicle is in the braking state. An anti-skid control device characterized by being provided with comparison means for determining.