JP3614103B2 - Leading vehicle tracking control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a preceding vehicle follow-up control device that travels on a host vehicle following a preceding vehicle that precedes the host vehicle, for example.
[0002]
[Prior art]
As such a preceding vehicle follow-up control device, for example, there is a device described in “New Model Vehicle NISSAN Cima” (Nissan Motor Corporation). The preceding vehicle follow-up control device performs acceleration / deceleration control of the host vehicle so that the inter-vehicle distance to the preceding vehicle determined by, for example, a laser radar becomes an appropriate value according to the traveling speed of the host vehicle. In this example, the acceleration of the host vehicle controls the opening of the throttle valve by a throttle actuator. Deceleration also controls braking fluid pressure from a braking fluid pressure generating device called a brake booster. A command current corresponding to the brake fluid pressure command value set by the control unit is output from the booster control unit to the brake booster, and a brake fluid pressure corresponding to the command current is output from the brake booster to each wheel cylinder. .
[0003]
[Problems to be solved by the invention]
By the way, the preceding vehicle follow-up control devices as described above include those that control the vehicle to a speed range of zero (stop), and those that control at a speed that is higher than the middle / low speed range. Further, for example, an actuator or a device such as TCS (Traction Control System), VDC (Vehicle Dynamics Control), ABS (Antilock Brake system), or so-called hardware is used. Is also possible. However, when diverting the hardware of the device that controls the vehicle to the speed range zero (stop) of the vehicle, or when diverting the dynamic characteristic control device, use these devices. The hardware of the device that does not assume the state where the vehicle stops completely or continues to stop, whereas in the preceding vehicle follow-up control device, if the preceding vehicle stops, the own vehicle also stops and the preceding vehicle If the vehicle continues to stop, the vehicle must also stop. At this time, the brake fluid pressure generated by the brake fluid pressure generating device such as the brake booster does not act directly on the end of the wheel cylinder, but is generated as a source pressure of the dynamic characteristic control device. For example, when the vehicle is stopped, the brake fluid pressure applied to the wheel cylinders must be maintained at a predetermined value that is greater than the allowable value required for stopping the vehicle, but the brake fluid pressure generating device such as a brake booster is used. Since the fluid pressure leaks from the brake fluid pressure system of the dynamic characteristic control device, when the brake fluid pressure to the wheel cylinder is held at a predetermined value that is greater than or equal to an allowable value, the brake fluid pressure of the dynamic characteristic control device is In view of leakage from the system, a predetermined braking fluid pressure must continue to be created. Furthermore, considering individual differences of brake fluid pressure generating devices such as brake boosters and changes in output characteristics over time, the output pressure from the brake fluid pressure generating device, that is, the brake fluid pressure is simply detected, and it exceeds the allowable value. If the command current is continuously output so as to have a predetermined value, there is a problem that the power consumption increases. Such a problem can be solved if a brake fluid pressure of a predetermined value that is equal to or greater than the allowable value is sealed in each wheel cylinder. To this end, a separate valve is provided at the end of the fluid pressure circuit for each wheel cylinder. It becomes necessary to intervene, and individual problems such as structural changes and high costs occur.
[0004]
The present invention has been developed to solve these problems, and an object of the present invention is to provide a preceding vehicle follow-up control device that can reduce power consumption without changing the structure or increasing the cost. It is what.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a preceding vehicle follow-up control device according to claim 1 of the present invention is arranged so that a predetermined inter-vehicle distance is maintained with respect to a preceding vehicle preceding the own vehicle. A preceding vehicle follow-up control device for running or stopping by following the host vehicle, wherein the braking fluid pressure commanding means for outputting a braking fluid pressure command value and the braking fluid pressure creating means for creating a braking fluid pressure In a preceding vehicle follow-up control device comprising command current output means for outputting a command current corresponding to a brake fluid pressure command value from the fluid pressure command means, the brake fluid pressure created by the brake fluid pressure creation means is detected. Braking fluid pressure detecting means, and the braking fluid pressure command means is detected by the braking fluid pressure detecting means when the braking fluid pressure to be created by the braking fluid pressure creating means is held at a predetermined value that is greater than or equal to an allowable value. Braking A holding braking fluid pressure command value with a gradually changing body pressure is set, and the power value of the command current from the command current output means for each holding braking fluid pressure command value is gradually reduced to a predetermined value or less. A holding braking fluid pressure command value is output.
[0006]
In the preceding vehicle follow-up control device according to claim 2 of the present invention, in the invention of claim 1, the braking fluid pressure command means adds to the braking fluid pressure detected by the braking fluid pressure detection means. The holding brake fluid pressure command value is set by gradually decreasing the added value.
According to a third aspect of the present invention, in the preceding vehicle follow-up control device according to the first or second aspect, the braking fluid pressure command means has a predetermined power value of the command current from the command current output means. The holding braking fluid pressure command value when the value becomes equal to or less than the value is set to the holding braking fluid pressure command value from the next time.
[0007]
【The invention's effect】
Thus, according to the preceding vehicle follow-up control device of the first aspect of the present invention, when the braking fluid pressure to be generated by the braking fluid pressure generating means is held at a predetermined value that is greater than or equal to the allowable value, the detected braking is performed. Set the holding brake fluid pressure command value by changing the fluid pressure little by little, and keep the power value of the command current from the command current output means for each holding brake fluid pressure command value gradually smaller than the predetermined value. Since the brake fluid pressure command value is output, for example, the holding brake fluid pressure command value when the power value of the command current is less than or equal to a predetermined value is output from the next to reduce power consumption thereafter. Can do.
[0008]
Further, according to the preceding vehicle follow-up control device of the present invention, since the addition value to be added to the detected brake fluid pressure is gradually reduced and the holding brake fluid pressure command value is set, Even when the braking fluid pressure from the braking fluid pressure generating means is increased by the difference or the output characteristics over time, and the power consumption increases as the braking fluid pressure command value decreases, the braking fluid pressure exceeds the allowable value. The holding brake fluid pressure command value at which the power consumption is not more than a predetermined value can be obtained with certainty.
[0009]
According to the preceding vehicle follow-up control device of the present invention, the holding brake fluid pressure command value when the power value of the command current from the command current output means becomes a predetermined value or less is determined from the next time. Therefore, the power consumption can be reduced without changing the structure and increasing the cost.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a vehicle configuration diagram of a preceding vehicle follow-up control device of the present invention. In this automatic follow-up control device, the braking force and engine for the front wheels 1F and the rear wheels 1R are able to travel following the preceding vehicle while maintaining an appropriate inter-vehicle distance with respect to the preceding vehicle preceding the host vehicle. Output, that is, a configuration capable of controlling the driving force. Among these, the braking force to the front wheel 1F and the rear wheel 1R is controlled by creating the brake fluid pressure to the wheel cylinder attached to each wheel by the brake booster 2. Further, the output of the engine, that is, the driving force is controlled by adjusting the opening of the throttle valve with the throttle actuator 3.
[0011]
On the other hand, a radar sensor 4 is provided in front of the vehicle, and a radar control unit 5 for controlling the radar sensor 3 is provided in the rear of the vehicle. The radar sensor 4 emits radio waves in front of the host vehicle and receives reflected waves from a preceding vehicle or the like. The radar control unit 5 determines whether the preceding vehicle and the preceding vehicle are based on a signal detected by the radar sensor 4. The inter-vehicle distance and the relative speed are calculated.
[0012]
Further, the vehicle is disposed in the brake booster 2 and is disposed in the pressure booster 2 that detects the brake fluid pressure in the master cylinder, and is also disposed in the brake booster 2, and the driver steps on the brake pedal. A brake release switch 8 that detects the opening of the throttle valve, a throttle sensor 9 that detects the opening of the throttle valve, a vehicle speed sensor 10 that detects the traveling speed of the host vehicle, a brake pedal switch 11 that is turned on when the brake pedal is depressed, and the steering angle of the steering wheel Various sensors such as a steering angle sensor 12 for detecting the above are provided.
[0013]
Further, in the cabin, the preceding vehicle following control system control switch 13 for operating the preceding vehicle following control and setting or changing the content thereof, or the preceding vehicle following control for displaying the content of the preceding vehicle following control is displayed. A system display 14 and a buzzer 15 for informing the system display 14 are also provided. Of these, the preceding vehicle follow-up control system control switch 13 has a plurality of switch functions, for example, a main switch function for turning the system ON and OFF, a vehicle speed adjustment switch function for adjusting the traveling speed of the host vehicle, and an inter-vehicle distance. It is equipped with an inter-vehicle distance adjustment switch function that makes the setting longer or shorter, a cancel switch function that releases control itself, and the like.
[0014]
FIG. 2 is a system configuration diagram of the preceding vehicle follow-up control device of the present embodiment. The preceding vehicle follow-up control system control unit 16 that controls the center of the preceding vehicle follow-up control device is disposed at the rear of the vehicle as shown in FIG. 1 and reads signals from the various switches or sensors described above. Further, the radar sensor 4 is operated via the radar control unit 5, and a control signal is output to the booster control unit 6 and the throttle actuator 3 based on the information, and the control contents are displayed on the preceding vehicle following control system display. 14 or the buzzer 15 is activated. In this embodiment, the automatic transmission control unit (A / TC / U in the figure) 17 for controlling the automatic transmission and the above-described VDC / TCS / ABS control unit (C / U in the figure) 18 are also mutually connected. It communicates, reads the operating status thereof, and provides operating information as a preceding vehicle following control device. The booster control unit 6 generates a command current corresponding to the braking fluid pressure command value from the preceding vehicle follow-up control system control unit 16 and outputs it to the brake booster 2.
[0015]
The preceding vehicle following control system control unit 16 includes an arithmetic processing unit such as a microcomputer. The main arithmetic processing performed in the arithmetic processing device is for acceleration / deceleration control in which the host vehicle travels while maintaining an appropriate inter-vehicle distance with respect to the preceding vehicle. For example, when there is no preceding vehicle, the set vehicle speed value is compared with the current vehicle speed value, and the throttle actuator 3 is controlled so as to approach the set vehicle speed. In addition, when a preceding vehicle appears that is slower than the set vehicle speed, the throttle valve opening is decelerated by adjusting it in the closing direction, and when a larger deceleration is required, a braking fluid pressure command value is output to the booster control unit. Then, the brake fluid pressure is generated and braking is performed by the wheel cylinder. When following the preceding vehicle, the throttle valve opening or the brake fluid pressure is controlled so that an appropriate inter-vehicle distance can be maintained in accordance with a change in the vehicle speed of the preceding vehicle. If the preceding vehicle disappears due to a change in the lane of the preceding vehicle or a change in the lane of the host vehicle during the follow-up traveling, the throttle valve opening is adjusted in the opening direction to accelerate the vehicle.
[0016]
If the preceding vehicle is stopped, the host vehicle must also stop. In the stop control, the brake fluid pressure generated by the brake booster 2 is maintained at a value necessary for the own vehicle to stop. Arithmetic processing performed by an arithmetic processing device such as a microcomputer in the preceding vehicle following control system control unit 16 during the stop control will be described based on the flowchart of FIG. In this arithmetic processing, timer interruption processing is performed every predetermined sampling time (in this case, 100 msec.). In this flowchart, no particular communication step is provided. For example, information obtained in the flowchart is stored in the storage device as needed, and necessary information is read out from the storage device as needed. In addition, the devices communicate with each other, and necessary information is always read from the device that mainly controls the information, and the transmitted information is stored in the storage device as needed.
[0017]
In step S1 of this calculation process, it is determined whether or not the stop control is being performed, that is, whether or not a braking fluid pressure holding command is being executed, according to the individual calculation processing performed in the same step. If there is, the process proceeds to step S2, and if not, the process proceeds to step S3.
In step S3, the fluid pressure rise control flag F_INTIs reset to “0” and the power saving control flag F_SAVEIs reset to “0”, the brake fluid pressure rise counter T and the brake fluid pressure command value holding counter C are cleared, the coefficient counter n is cleared, and then the process returns to the main program.
[0018]
On the other hand, in step S2, the brake fluid pressure rise control flag F_INTIs a reset state of “0”, the brake fluid pressure rise control flag F_INTIf is in the reset state, the process proceeds to step S4, and if not, the process proceeds to step S5.
In the step S4, the predetermined value P when the vehicle is stopped according to the individual calculation processing performed in the step._ACC-STPBrake fluid pressure command value P_ACCAnd then the process proceeds to step S6. However, although details are not shown here, immediately after the output is started, the fluid pressure command value is increased so as to gradually increase, and the command value is a predetermined value P when the vehicle is stopped._ACC-STPWhen the value is reached, the value is held.
[0019]
In step S6, a brake fluid pressure rising counter T is set to a predetermined value T₀It is determined whether or not the brake fluid pressure rise counter T is equal to or greater than a predetermined value T₀If so, the process proceeds to step 7; otherwise, the process proceeds to step S8.
In step S7, the brake fluid pressure rise control flag F_INTIs set to "1" and then the process proceeds to step S9.
[0020]
In step S9, the coefficient counter n is cleared and the process returns to the main program.
In step S8, the brake fluid pressure rise counter T is incremented and then the program returns to the main program.
In step S5, the power saving control flag F_SAVEIs a reset state of “0”, and the power saving control flag F_SAVEIf is in a reset state, the process proceeds to step S10, and if not, the process proceeds to step S11.
[0021]
In step S11, a coefficient counter predetermined value n set in step S19 described later.₀Is set to the value of the coefficient counter n, and then the process proceeds to step S10.
In step S10, the brake fluid pressure command value P in accordance with the following equation 1 is performed in accordance with individual calculation processing performed in the step._ACCIs calculated and output, and then the process proceeds to step S12.
[0022]
P_ACC= P_SENS+ ΔP₀₀-N · ΔP₀                        ……… (1)
However, P_SENSIs the brake fluid pressure detected by the pressure sensor 8, ΔP₀₀Is a predetermined addition value set in advance, ΔP₀Is a predetermined change amount set in advance. For example, in this embodiment, ΔP₀₀Is 0.4 bar, ΔP₀Is 0.2bar, such as ΔP₀<ΔP₀₀Is set to
[0023]
In step S12, the power saving control flag F_SAVEIs a reset state of “0”, and the power saving control flag F_SAVEIf is in a reset state, the process proceeds to step S13, and if not, the process proceeds to step S14.
In step S13, the brake fluid pressure command value holding counter C is set to a predetermined value C.₀It is determined whether or not the braking fluid pressure command value holding counter C is a predetermined value C.₀If so, the process proceeds to step S15; otherwise, the process proceeds to step S16.
[0024]
In step S15, the average power value I is determined according to the individual calculation process performed in the step.² _AVEAfter calculating, the process proceeds to step S17. This average power value I² _AVEThe brake fluid pressure command value holding counter C is the predetermined value C₀Within a predetermined time until counting up at the brake fluid pressure command value P_ACCIs obtained by the power consumption value of the brake booster 2 when it is held at the value calculated by the above-mentioned formula 1, specifically, the square value of the current value.
[0025]
In step S17, the average power value I calculated in step S15 is calculated.² _AVEIs a predetermined value I set in advance² _AVE0It is determined whether or not the average power value I² _AVEIs the predetermined value I² _AVE0If so, the process proceeds to step S18; otherwise, the process proceeds to step S19.
In step S18, the coefficient counter n is incremented, and then the process proceeds to step S14.
[0026]
In step S19, the power saving control flag F_SAVEIs set to “1”, and then the process proceeds to step S20.
In step S20, the coefficient counter n is set to the coefficient counter predetermined value n.₀Then, the process proceeds to step S14.
In step S16, the brake fluid pressure command value holding counter C is incremented, and then the process proceeds to step S14.
[0027]
In step S14, the brake fluid pressure P detected by the pressure sensor 8 is obtained._SENSIs a preset allowable value P_SENS0It is determined whether or not the brake fluid pressure P_SENSIs allowable value P_SENS0If it is the following, the process proceeds to step S21. If not, the process returns to the main program.
In step S21, the fluid pressure rise control flag F_INTIs reset to “0”, and then the process proceeds to step S22.
[0028]
In step S22, the brake fluid pressure command value holding counter C and the fluid pressure rise counter T are cleared, and then the process returns to the main program.
Next, the operation of this arithmetic processing will be described using the timing chart of FIG. This timing chart shows the time t during the preceding vehicle following control.₀₀And the braking fluid pressure P when the vehicle continues to stop and the command current value I of the booster control unit 8_ACCAnd average power value I² _AVEFIG. 4 a shows the command current value I of the booster control unit 8._ACC4b, the average power value I of the booster control unit 8 is shown in FIG.² _AVEIn FIG. 4c, the braking fluid pressure command value P_ACCAnd detected value P_SENSShows the change over time.
[0029]
Time t of this timing chart₀₀The brake fluid pressure P is used to decelerate the vehicle until the vehicle stops at_SENSIs a predetermined value P required for deceleration_SENS-BFWas maintained. And time t₀₀When the host vehicle stops, the brake fluid pressure rise control flag F_INTHas been reset, the process proceeds from step S1 to step S4 of the calculation process of FIG. 3 to step S4, where the brake fluid pressure command value P_ACCGradually increases to the time t₀₁The predetermined value P when the vehicle stops_ACC-STPSince then, the braking fluid pressure command value P_ACCIs the predetermined value P_ACC-STPHold on. Thus, the fluid pressure command value P_ACCCommand current value I when gradually increasing_ACCIs the predetermined value I_STP-INTIt becomes constant and power is consumed accordingly. In addition, the braking fluid pressure P detected by the operation of the brake booster 2_SENSRises slightly after the time t₀₁The predetermined value P when the vehicle is stopped_ACC-STPA slightly lower value.
[0030]
However, the time t₀₁Thereafter, the brake fluid pressure command value P_ACCIs the predetermined value P_ACC-STPIf the current value is held at, the command current value I from the booster control unit 6_ACCBecomes smaller and the output braking fluid pressure P_SENSBecause the ability to further pressurize is lost, the brake fluid pressure P_SENSGradually becomes smaller. In the calculation process of FIG. 3, the flow from step S6 to step S8 is repeated, and the brake fluid pressure rise counter T incremented here is set to the time t.₀₂At a predetermined value T₀That is, that is, counts up, proceeds to step S7, brake fluid pressure rise control flag F_INTAnd the coefficient counter n is cleared in the next step S9.
[0031]
Therefore, when the calculation process of FIG. 3 is performed next, the process proceeds from step S2 to step S5, where the power saving control flag F_SAVEHas been reset, the process proceeds to step S10, and this time t₀₂The predetermined value P when the vehicle is stopped_ACC-STPBrake fluid pressure P has been reduced accordingly_SENSTo the predetermined addition value ΔP₀₀Is the braking fluid pressure command value P_ACC(Because the coefficient counter n is “0”). Along with this, the command current value I from the booster control unit 6_ACCIs the predetermined value I_{ACC (n = 0)}And the brake booster 2 generates pressure, so the braking fluid pressure P_SENSThe pressure reduction slope is slightly reduced. However, since it does not suppress the pressure reduction, the braking fluid pressure P_SENSThe decompression of continues.
[0032]
The brake fluid pressure P that continues to be reduced in this way_SENSOn the other hand, in the calculation process of FIG. 3, the fluid pressure command value P is similarly determined in step S10._ACCIs calculated and output. At the same time, the process proceeds from step S12 to step S13 to step S16, where the flow of incrementing the brake fluid pressure command value holding counter C is repeated. Eventually, time t₀₃The brake fluid pressure command value holding counter C is set to a predetermined value C₀When the above is reached, that is, when the count is counted up, the process proceeds from step S13 to step S15 in the calculation process of FIG.₀₂To the time t₀₃Average power value up to² _AVEIs calculated. This time t₀₃I calculated by² _AVEIs the predetermined value I² _AVE0Larger predetermined value I² _{AVE (n = 0)}Therefore, in the arithmetic processing of FIG. 3, the process proceeds from step S17 to step S18, and the coefficient counter n is incremented to “1”. Therefore, when the calculation process of FIG. 3 is performed next, in step S10, the braking fluid pressure P at that time is calculated._SENSTo the predetermined addition value ΔP₀₀And then the predetermined change amount ΔP₀Is the brake fluid pressure P_ACCWill be set to.
[0033]
This time t₀₃Subsequent braking fluid pressure command value P_ACCIs the time t₀₃Since it is smaller than the previous one, the command current value I from the booster control unit 6_ACCIs the predetermined value I_{ACC (n = 0)}Smaller predetermined value I_{ACC (n = 1)}Braking fluid pressure P_SENSHas a slightly larger slope of decompression than before. The brake fluid pressure P that continues to be reduced in this way_SENSOn the other hand, in the calculation process of FIG. 3, the fluid pressure command value P is similarly determined in step S10._ACCIs calculated and output. At the same time, the process proceeds from step S12 to step S13 to step S16, where the flow of incrementing the brake fluid pressure command value holding counter C is repeated. Eventually, time t₀₄The brake fluid pressure command value holding counter C is set to a predetermined value C₀When the above is reached, that is, when the count is increased, the process proceeds again from step S13 to step S15 of the calculation process of FIG.₀₃To the time t₀₄Average power value up to² _AVEIs calculated. This time t₀₄Average power value I calculated by² _{AVE (n = 1)}Is also the predetermined value I² _AVE0Larger predetermined value I² _{AV E (n = 1)}Therefore, in the arithmetic processing of FIG. 3, the process proceeds from step S17 to step S18, and the coefficient counter n is incremented to “2”. Therefore, when the calculation process of FIG. 3 is performed next, in step S10, the braking fluid pressure P at that time is calculated._SENSTo the predetermined addition value ΔP₀₀And then the predetermined change amount ΔP₀The value obtained by subtracting the double value of the brake fluid pressure P_ACCWill be set to. In this embodiment, the braking fluid pressure command value P at this time_ACCBrake fluid pressure P_SENSMatched.
[0034]
This time t₀₄Subsequent braking fluid pressure command value P_ACCIs the time t₀₄Since it is smaller than the previous one, the command current value I from the booster control unit 6_ACCIs the predetermined value I_{ACC (n = 1)}Smaller predetermined value I_{ACC (n = 2)}Braking fluid pressure P_SENSHas a slightly larger slope of decompression than before. The brake fluid pressure P that continues to be reduced in this way_SENSOn the other hand, in the calculation process of FIG. 3, the fluid pressure command value P is similarly determined in step S10._ACCIs calculated and output. At the same time, the process proceeds from step S12 to step S13 to step S16, where the flow of incrementing the brake fluid pressure command value holding counter C is repeated. Eventually, time t₀₅The brake fluid pressure command value holding counter C is set to a predetermined value C₀When the above is reached, that is, when the count is increased, the process proceeds again from step S13 to step S15 of the calculation process of FIG.₀₄To the time t₀₅Average power value up to² _AVEIs calculated. This time t₀₅Average power value I calculated by² _{AVE (n = 2)}Is the predetermined value I² _AVE0Therefore, in the calculation process of FIG. 3, the process proceeds from step S17 to step S19, and the power saving control flag F_SAVEIn the next step S20, the coefficient counter n at that time, that is, “2” is set to the coefficient counter n.₀Set to.
[0035]
In this timing chart, the time t₀₅The detected brake fluid pressure P at_SENSIs the allowable value P required for the stop_SENS0Therefore, the process proceeds from step S14 to step S21, where the brake fluid pressure rise control flag F_INTIn step S22, the brake fluid pressure rising counter T and the brake fluid pressure command value holding counter C are cleared.
[0036]
Therefore, when the calculation process of FIG. 3 is performed next, the time t₀₀Similarly to step S1, the process proceeds from step S1 to step S4 to step S4, where the brake fluid pressure command value P_ACCGradually increases to the time t₀₆The predetermined value P when the vehicle stops_ACC-STPSince then, the braking fluid pressure command value P_ACCIs the predetermined value P_ACC-STPHold on. Also at this time, the command current value I_ACCIs the predetermined value I_STP-INTIt becomes constant and power is consumed accordingly. In addition, the braking fluid pressure P detected by the operation of the brake booster 2_SENSRises slightly after the time t₀₁The predetermined value P when the vehicle is stopped_ACC-STPA slightly lower value.
[0037]
And the time t₀₆Thereafter, the brake fluid pressure command value P_ACCIs the predetermined value P_ACC-STPIf the current value is held at, the command current value I from the booster control unit 6_ACCBecomes smaller and the braking fluid pressure P_SENSGradually becomes smaller. In the calculation process of FIG. 3, the flow from step S6 to step S8 is repeated, and the brake fluid pressure rise counter T incremented here is set to the time t.₀₇At a predetermined value T₀That is, that is, counts up, proceeds to step S7, brake fluid pressure rise control flag F_INTAnd the coefficient counter n is cleared in the next step S9.
[0038]
Therefore, when the calculation process of FIG. 3 is performed next, the process proceeds from step S2 to step S5. Here, the power saving control flag F_SAVEIs set, the process proceeds to step S11, where the coefficient counter predetermined value n₀Is set to the value of the coefficient counter n. Accordingly, when the process proceeds to the next step S10, the brake fluid pressure P_SENSTo the predetermined addition value ΔP₀₀And the predetermined change amount ΔP₀Is obtained by multiplying the coefficient counter by n, that is, a predetermined change amount ΔP.₀The value obtained by subtracting the double value of the brake fluid pressure command value P_ACCSet to In the arithmetic processing of FIG. 3, the power saving control flag F_SAVEIs set, and the flow of jumping from step S12 to step S14 is repeated, so that the detected braking fluid pressure P is detected._SENSIs the allowable value P required for the stop_SENS0The command current value I from the booster control unit 6 until_ACCIs the time t₀₄The same predetermined value I as after_{ACC (n = 2)}And the average power value I² _{AVE ( n = 2)}Is also the predetermined value I² _AVE0It becomes as follows.
[0039]
Thus, in the present embodiment, the braking fluid pressure P detected when the braking fluid pressure is maintained, such as when the vehicle is stopped._SENSBrake fluid pressure command value P_ACCAnd set each brake fluid pressure command value P_ACCMean power value I of booster control unit 6 against² _AVEIs the predetermined value I² _AVE0Gradually smaller braking fluid pressure command value P so that_ACCCommand current I_ACCAverage power value I² _AVEIs the predetermined value I² _AVE0Braking fluid pressure command value P when_{ACC (n = 2)}Is output from the next, so that power consumption thereafter can be reduced.
[0040]
Also, the detected braking fluid pressure P_SENSThe value to be added to the addition value ΔP (= ΔP₀₀-N · ΔP₀), The power consumption I consumed by the booster control unit 6²5 and the added value ΔP may be as indicated by a broken line, for example, due to individual differences of the booster control unit 6 or changes with time, even if the original characteristic is as indicated by a solid line in FIG. In the present embodiment, the addition value ΔP is gradually reduced to reduce the braking fluid pressure command value P._ACCTherefore, the brake fluid pressure command value P is determined by the individual difference of the booster control unit 6 and the change over time._ACCEven when the power consumption increases as the value of the brake fluid decreases, the brake fluid pressure P_SENSTo tolerance P_SENS0While maintaining the above, the average power value I² _AVEIs the predetermined value I² _AVE0Brake fluid pressure command value P_ACCCan be assured.
[0041]
From the above, the preceding vehicle following control system control unit 16 and the entire arithmetic processing of FIG. 3 constitute the braking fluid pressure command means of the present invention, and similarly, the brake booster 2 constitutes the braking fluid pressure generating means. The booster control unit 6 constitutes command current output means, and the pressure sensor 8 constitutes braking fluid pressure detection means.
[0042]
In the following embodiments, a microcomputer is used for each arithmetic processing unit, but various logic circuits may be used instead.
[Brief description of the drawings]
FIG. 1 is a vehicle configuration diagram showing an embodiment of a preceding vehicle follow-up control device of the present invention.
FIG. 2 is a system configuration diagram of the preceding vehicle follow-up control device of FIG. 1;
FIG. 3 is a flowchart showing calculation processing during stopping performed in the preceding vehicle follow-up control system control unit of FIG. 2;
4 is a timing chart for explaining the operation of the arithmetic processing of FIG. 3;
FIG. 5 is an explanatory diagram showing the relationship between the power consumption of the booster control unit and the fluid pressure addition value.
[Explanation of symbols]
1F, 1R are wheels
2 is a brake booster
3 is a throttle actuator
4 is a radar sensor
5 is a radar control unit
6 is a booster control unit
8 is a pressure sensor
16 is a preceding vehicle following control system control unit

Claims (4)

A preceding vehicle follow-up control device that travels or stops by causing the preceding vehicle to follow the preceding vehicle so that a predetermined inter-vehicle distance is maintained with respect to the preceding vehicle preceding the own vehicle, and a braking fluid pressure command value And a command current output unit for outputting a command current corresponding to a brake fluid pressure command value from the brake fluid pressure command unit to the brake fluid pressure generating unit for generating the brake fluid pressure A preceding vehicle follow-up control device comprising: a brake fluid pressure detecting means for detecting a brake fluid pressure created by the brake fluid pressure creating means, wherein the brake fluid pressure command means is created by the brake fluid pressure creating means. When the braking fluid pressure to be held is held at a predetermined value that is greater than or equal to an allowable value, a holding braking fluid pressure command value is set by gradually changing the braking fluid pressure detected by the braking fluid pressure detecting means, and each holding braking pressure is set. Fluid pressure As power value of the command current from the command current output means for decree value less than or equal to a certain value, the preceding vehicle following control apparatus and outputs a progressively smaller holding brake hydraulic pressure command value. 2. The brake fluid pressure command means sets a holding brake fluid pressure command value by gradually reducing an addition value to be added to the brake fluid pressure detected by the brake fluid pressure detection means. Preceding vehicle follow-up control device. The braking fluid pressure command means sets the holding braking fluid pressure command value when the power value of the command current from the command current output means becomes a predetermined value or less to the holding braking fluid pressure command value from the next time. The preceding vehicle follow-up control device according to claim 1 or 2. A preceding vehicle follow-up control device that travels or stops by causing the preceding vehicle to follow the preceding vehicle so that a predetermined inter-vehicle distance is maintained with respect to the preceding vehicle preceding the own vehicle, and a braking fluid pressure command value And a command current output unit for outputting a command current corresponding to a brake fluid pressure command value from the brake fluid pressure command unit to the brake fluid pressure generating unit for generating the brake fluid pressure A preceding vehicle follow-up control device comprising: a braking fluid pressure detecting means for detecting a braking fluid pressure created by the braking fluid pressure creating means; and the command current output means created by the braking fluid pressure creating means. The command current is set so that the power value of the command current becomes equal to or less than a predetermined value according to the brake fluid pressure detected by the brake fluid pressure detection means when the power brake fluid pressure is held at a predetermined value that is greater than or equal to an allowable value. Gradually Preceding vehicle following control apparatus characterized by changing the old value.

Images