JP4879462B2 - Vehicle braking method and vehicle braking device - Google Patents

Description

  The present invention relates to a vehicle braking method and a vehicle braking device for braking and stopping a host vehicle by brake assist (hereinafter referred to as BA).

  Conventionally, in a vehicle having a BA function, if the driver depresses the brake pedal at a certain depressing speed at a certain amount or more, the BA of the brake mechanism is activated (intervened) as an emergency state of collision avoidance occurs. When the brake pedal is depressed, a braking force larger than the normal braking force is generated.

  At that time, in order to ensure sufficient safety, the distance between the vehicle and the vehicle's front object (obstacle) such as a preceding vehicle ahead is detected, and the shorter the distance (the closer it is), the more It is predicted that the possibility is high, and it is proposed to increase the assist force of the BA (see, for example, Patent Document 1).

  On the other hand, as an object ahead of the vehicle (obstacle) that may collide with the vehicle in front of the driving lane, not only an object that moves (runs) at a certain speed or more, such as a vehicle (preceding vehicle), but also a vehicle There are also people and bicycles that are extremely slow compared to the other.

  In order to prevent the BA from inadvertently operating and preventing smooth travel, the distance between the vehicle and the object detected by the laser radar or the like is less than the set safety distance (shortened). If the BA is operated in response to the depression of the brake pedal, the above-mentioned object such as a person or a bicycle moves slowly compared to an automobile or the like, so it is overlooked. Since a situation where it is not detected or a situation where it is detected unnecessarily (excessively) occurs, for such an object moving at low speed, only when the detection below the safe distance continues for a predetermined time at a predetermined frequency It is also proposed to intervene BA (see, for example, Patent Document 2).

JP-A-10-297452 (paragraphs [0033]-[0034], [0042]-[0044], FIG. 1, FIG. 3, FIG. 5, FIG. 6) Japanese Patent Laid-Open No. 11-255087 (paragraphs [0003], [0013], FIGS. 1 and 3)

As in the prior art, the possibility of collision is predicted by paying attention to the distance between the host vehicle and its front object (obstacle), and the assist force of the BA increases as the distance decreases. since the constant velocity of the preceding object with respect to the vehicle to predict the (relative speed or actual speed (absolute speed)) is not taken into account, when the emergency condition collision avoidance occurs, the timing of B a intervention is not appropriate, There is a risk of BA intervention being too early or too late.

  Similarly, with respect to an object in front of the own vehicle that moves at a low speed, only when the detection distance between the own vehicle and the object is less than the safe distance continues for a predetermined time at a predetermined frequency, Even if it is intended to ensure proper driving, it cannot be said that the prediction of the possibility of collision is sufficiently high by itself, and when a collision avoidance emergency situation occurs, the BA intervention timing may not be an appropriate timing. Therefore, there is a possibility that the BA cannot be reliably intervened at the optimum timing.

Further, in the braking of this type of BA intervention, when the emergency condition collision avoidance occurs, there is a possibility that B A does not intervene for some reason.

The judgment of the possibility of collision and the operation of the brake pedal have individual differences, and depending on the driver, the operation may tend to be delayed.

  An object of the present invention is to improve safety by ensuring that a BA intervenes at an optimal timing when an emergency state for avoiding a collision occurs.

In order to achieve the above-described object, the vehicle braking method of the present invention is configured such that the combination of the distance between the traveling vehicle and the object ahead of the vehicle and the measured value of the relative speed of the object ahead of the vehicle with respect to the vehicle is set. Because it becomes a combination of the predicted collision range, when detecting the collision avoidance state where the possibility of collision between the own vehicle and the object ahead of the own vehicle is high, regardless of whether or not the driver depresses the brake pedal, the vehicle brake mechanism, the vehicle braking method for controlling the braking state BA intervened, the time difference between the timing of the daily operation, said main collision avoidance state detection timing and the driver performs a depression operation of the brake pedal BA intervention Based on the average value, the slower the driver's brake operation, the wider the collision prediction range, making it easier to detect the collision avoidance state. That (claim 1).

Further, the vehicle braking device of the present invention is a collision in which a combination of a measured value of the distance between the traveling vehicle and the object ahead of the vehicle and a measured value of the relative speed of the object ahead of the vehicle is set. Because it is a combination of prediction ranges, it detects a collision avoidance state where the possibility of collision between the vehicle and the object ahead of the vehicle is high, and regardless of whether or not the driver depresses the brake pedal, the mechanism, in a vehicle brake system for controlling the braking state BA intervened, in daily operation, the average time difference between the timing at which the detection timing and the driver of a substantial collision avoidance state performs a depression operation of the brake pedal BA intervention Based on the above, it is characterized by having a correction function that makes it easier to detect the collision avoidance state by expanding the collision prediction range as the driver's brake operation is slower ( Motomeko 2).

According to the first and second aspects of the invention, the slower the brake operation for BA intervention by the driver of the own vehicle, the wider the predicted collision range becomes, so that the collision avoidance state can be detected more easily. Since it is detected early, the possibility of collision can be monitored and detected in consideration of the slow speed of the driver's brake operation. When the possibility of collision becomes high, the condition is automatically or on condition that the driver shows his intention to brake with his / her foot on the brake pedal, that is, regardless of whether or not the driver depresses the brake pedal. Intervenes.

Therefore, the possibility of collision is monitored and detected in consideration of the slow speed of the brake operation of the driver, regardless of the relative speed of the object ahead of the vehicle and whether or not the driver is stepping on the brake pedal. Regardless of the operation speed, etc., safety can be improved by ensuring that the BA intervenes at an optimal timing.

  Next, an embodiment of the present invention will be described with reference to FIGS.

1 is a block diagram of a braking device provided in the host vehicle 1, FIG. 2 is a detailed configuration diagram of the brake mechanism (brake actuator) of FIG. 1, and FIGS. 3 and 4 are flowcharts for explaining the operation of FIG. 5 is an explanatory diagram of a combination of the distance and speed (relative speed) in the collision prediction range of FIG. 1, and FIG. 6 is an explanatory diagram of the traveling state of the vehicle.

<Configuration>
A. "overall structure"
The vehicle 1 shown in FIG. 1 detects and monitors the distance between the vehicle 1 and the object ahead of the vehicle such as the preceding vehicle and the relative speed of the object ahead of the vehicle 1 during traveling. Similar to a well-known vehicle having a so-called follow-up running function or the like, it is provided with a front exploration sensor 2 comprising exploration radar such as laser radar, millimeter wave radar, imaging means such as a CCD camera, or a combination thereof (sensor fusion). The sensor 2 captures and recognizes an object ahead of the host vehicle such as a preceding vehicle by a known radar scan, image processing of a captured image, or a combination thereof.

  The electronically controlled vehicle 1 includes various sensors such as a wheel speed sensor 3 and a stop lamp switch 4 and switches, and the wheel speed sensor 3 detects the vehicle speed (vehicle speed) from the wheel speed of the vehicle 1. The lighting of the stop lamp is detected from the contact signal of the stop lamp switch 4.

  When the driver puts his / her foot on the brake pedal and the brake pedal is slightly displaced in the depressing direction, the stop lamp switch 4 is pressed and turned on by this displacement, and generates a stop lamp lighting contact signal.

  Then, the detection signals of the sensors 2 and 3 and the contact signal of the stop lamp switch 4 are taken in by an electronic control unit (ECU) 5 for braking control having a microcomputer configuration. Various control programs are executed, and the brake actuator 7 is controlled based on the operation of the driver's brake pedal and the various signals taken in.

  Further, when the driver indicates the intention to put the foot on the brake pedal to apply the brake, the ECU 5 is based on the contact signal of the stop lamp switch 4 indicating the lighting operation of the stop lamp 8 regardless of the depression amount of the brake pedal. Turns on the stop lamp 8.

B. “Configuration of brake actuator 7”
The brake actuator 7 is a hydraulic pump type having a BA function, and a master cylinder (hereinafter referred to as M / C) pressure generated according to a driver's brake pedal depression force is used as a normal control pressure (cylinder pressure) of the wheel cylinder. Then, during an emergency braking in which the M / C pressure becomes equal to or higher than the set pressure of the BA intervention start reference by the depression operation for avoiding the collision of the brake pedal, that is, the depression operation in which the depression amount becomes a predetermined amount or more with a change over time of a certain amount For example, a configuration as shown in FIG. 2 is used to generate a large braking force by the intervention of the BA and to stop the vehicle 1 quickly.

  The pressurizing mechanism of the brake actuator 7 is configured in the same manner as a general hydraulic pump type brake actuator having a BA function, and its hydraulic system is composed of two systems of the right side and the left side of the same configuration. For convenience of explanation, only the right system portion related to the right front wheel and the rear wheel is shown, and the left system portion related to the left front wheel and the rear wheel is not shown.

  An M / C 73 is connected to the brake pedal 71 via a brake booster 72, and a reservoir tank 74 that stores brake fluid (brake oil) is connected to the M / C 73.

  Further, a hydraulic pressure path 701 as an upstream inflow trunk is connected to the M / C 73, and the brake hydraulic pressure corresponding to the depression force of the brake pedal 71 of the driver passes through the hydraulic pressure path 701 as the M / C pressure. The upstream valve 702 of the pressure regulating valve is transmitted to the upstream valve 702. The upstream valve 702 is opened and closed by the ECU 5 until the M / C pressure is increased to the BA intervention start reference set pressure Pr from the start of the brake operation. Controlled.

  Therefore, at the time of a normal depression operation of the brake pedal 71 in which the M / C pressure becomes lower than the set pressure Pr, the M / C pressure is directly changed from the hydraulic pressure path 703 as the downstream inflow trunk path to the inflow side connection point α, It is transmitted to the front and rear downstream valves 705F and 705R which are pressure increasing valves through the branched front and rear branch paths 704F and 704R, and further, via the front and rear branch paths 706F and 706R, The vehicle 1 is transmitted to the wheel cylinder 10 </ b> F of the front wheel 9 </ b> F and the wheel cylinder 10 </ b> R of the rear wheel 9 </ b> R, and the host vehicle 1 stops (stops) with a braking force corresponding to the depression pressure of the brake pedal 71.

  The front and rear downstream valves 708F and 708R, which are pressure reducing valves, are connected to the branch paths 706F and 706R via the front and rear branch paths 707F and 707R. The downstream valves 708F and 708R are connected before the brake control. It is kept open and is closed during normal brake control and BA brake control, and is opened and closed during automatic brake control in automatic operation or the like.

  Next, the front and rear branch paths 709F and 709R are connected to the downstream valves 708F and 708R, and both branch paths 709F and 709R are coupled at one end of a hydraulic pressure path 710 as an outflow trunk path. Is connected to the suction path 712 of the hydraulic pump 711 of the pressurizing mechanism via the outflow side connection point β.

  The pressure path 714 on the discharge side of the pump 711 driven by the motor 713 is connected to the inflow side connection point α by providing a check valve 715, an accumulator 716, and a pressure switch 717 in order from the pump 711 side. Furthermore, a pressurized liquid supply path 718 is provided between the M / C 73 side end of the hydraulic pressure path 701 and the outflow side connection point β, and a switching valve in order from the hydraulic pressure path 701 side is provided in this path 718. An upstream valve 719 and a check valve 720 are provided. The check valve 715 prevents the backflow from the inflow side connection point α to the pump 711, and the check valve 720 prevents the backflow from the outflow side connection point β to the path 718.

  2, reference numerals 721, 722F, 722R, and 723 are pressure switches for the hydraulic pressure path 701, the branch paths 706F, 706R, and the pressurization path 713, respectively, and the wheel cylinders of the M / C pressure, front and rear wheels 9F, 9R. The pressure and the BA assist pressure are detected, and a signal of the detected pressure is output to the ECU 5.

  When the driver depresses the brake pedal 71 quickly and greatly by an emergency depressing operation for collision avoidance, the M / C pressure is increased to the set pressure Pr in a very short time, and the increase in the set pressure Pr is detected. Based on this, the ECU 5 detects the occurrence of the emergency depressing operation for avoiding the collision and executes the BA control, drives the motor 713 and opens the upstream valve 719 to intervene in the BA.

  At this time, the brake fluid for assist pressurization is sent from the reservoir tank 74 to the hydraulic pump 711 via the M / C 73 and the path 718, and the assist pressure of BA is formed by the discharge of the hydraulic pump 711 and the accumulated pressure of the accumulator 516. When the assist pressure reaches a set level, the upstream valve 519 is closed.

  Then, when the driver depresses the brake pedal, the control pressure having a large M / C pressure + assist pressure obtained by adding the assist pressure to the M / C pressure is supplied from the inflow side connection point α through the downstream valves 705F and 705R. It is transmitted to the cylinders 10F and 10R, and a larger deceleration is generated than in the case of only the M / C pressure, and the own vehicle 1 is stopped by emergency braking.

C. “Means Formed by ECU 5”
When there is a high possibility of collision between the host vehicle 1 and an object ahead of the host vehicle, the ECU 5 automatically intervenes the BA without performing the emergency depressing operation (depressing the brake pedal) for avoiding the collision. Basically, a collision avoidance state detection program comprising steps S1 to S5 in FIG. 3 and a BA intervention control program comprising steps Q1 to Q5 in FIG. 4 are executed, and the following running state detection means and braking control means are provided. .

(I) Traveling state detection means This means includes a combination of a distance between the host vehicle 1 and a front object such as a preceding vehicle and a measurement value of a relative speed of the front object of the host vehicle 1 and a set collision prediction range. of a pre-Symbol distance and means for comparing the combination of the relative velocity, to form the step S1~S4 in FIG 3, after setting the initial values read out various reference values, etc. from the storage unit 6 by step S1 Based on the search result of the sensor 2, the vehicle forward object such as the preceding vehicle is recognized from the presence of the reflected wave, and the distance between the vehicle 1 and the vehicle forward object from the transmission / reception time difference in step S2 (The inter-vehicle distance, etc.) is measured, and the relative speed of the object ahead of the vehicle is measured from the time variation of the measured distance in step S3, and further, the combination of the measured distance and the relative speed is set and set in step S4. did Collision prediction range Noso comparing the combination of these.

Specifically, by obtaining a combination of the distance between the vehicle 1 in front of the vehicle and the object ahead of the vehicle, and the relative speed of the object ahead of the vehicle from various driving experiments or the like, for example, FIG. distance D of the collision prediction range of 5 to obtain a velocity (relative velocity) threshold line DV plot of combinations of V.

  At this time, the range above the threshold line DV in FIG. 5 is the avoidance marginal region I where collision avoidance is not necessary, and the region below the threshold line DV is the region where collision avoidance is necessary where collision avoidance is necessary. II, and this region II is the collision prediction range.

  The distance D and the speed V of each combination of the threshold lines DV are set as the threshold distance Dref and the threshold speed Vref, and the measured distance D and the speed V obtained while the vehicle 1 is traveling are Dx and Vx. For example, in step S1, the threshold distance Dref and the threshold velocity Vref of each combination are read from the storage unit 6, and the measured values Dx and Vx are obtained every moment in steps S2 and S3. The threshold speed Vref of the threshold distance Dref equal to the value Dx is compared with the measured value Vx.

  Then, until the ignition switch of the vehicle 1 is turned off and the engine is stopped, the process returns from step S4 to step S1 through step S5, and the above comparison process is repeated.

(Ii) Braking control means This means is based on the comparison of the traveling state detection means, and the combination of the measured values Dx and Vx becomes the combination of the collision prediction ranges, and the distance between the own vehicle 1 and the object ahead of the own vehicle. And when the collision avoidance state in which the possibility of collision between the host vehicle 1 and the host vehicle front object becomes high is detected from the relative speed of the host vehicle front object with respect to the host vehicle, automatically or on condition that the stop lamp 8 is turned on. The brake mechanism 7 of FIG. 2 is controlled to a braking state in which BA intervenes. Therefore , the brake actuator 7 is controlled to be in a braking state in which BA intervenes regardless of whether or not an emergency stepping operation is performed, and basically, steps Q1 to Q5 in FIG. 4 are formed.

As a result of the comparison in step S4 of FIG. 3, the measured value Vx is larger (faster) than the threshold speed Vref of the threshold distance Dref equal to the measured value Dx, and as shown in the running state diagram of FIG. distance measured is equal to or less than the safety distance Dsafe that takes into account the velocity, the step Q1 of FIG. 4, based on the result of the comparison, likely of collision between the vehicle 1 and the own vehicle forward object When it is detected that the vehicle is in a traveling state that requires collision avoidance, that is, a state that requires collision avoidance, even if the M / C pressure is not increased to the set pressure Pr, As in the case where the M / C pressure is increased to the set pressure Pr and step Q5 is passed in an affirmative (YES), the process proceeds to step Q2, the motor 713 is driven, the upstream valve 719 is opened, and the BA intervention braking control is performed. Was rows, in step Q3, Q4, unless it detects the cancellation thereof braking stop or main collision avoidance state of the vehicle 1, continued braking control of BA intervention.

  Note that reference numeral 11 in FIG. 6 denotes a preceding vehicle as an object ahead of the host vehicle, and reference numeral 2 a in the figure denotes a search range of the search sensor 2.

<Operation>
Next, a specific operation of this B A intervention.

  First, when the ignition key of the host vehicle 1 is turned on (engine start), the initial setting in step S1 in FIG. 3 is executed, and the ECU 5 reads the collision prediction reference values Dref, Vref, etc. held in the storage unit 6. To initialize the control environment.

Next, in steps S2 to S4 in FIG. 3, based on the measurement output of the search sensor 2 and the wheel speed sensor 3, the vehicle 1 and the preceding vehicle, bicycle, person, etc. that are captured and recognized by the search sensor 2 are detected. The comparison of the combination of the measured values Dx and Vx of the distance in time with the object ahead of the host vehicle and the relative speed of the object ahead of the host vehicle and the combination of the threshold distance Dref and the threshold speed Vref in the collision prediction range is repeated.

Then, in step Q1 of FIG. 4, the distance measurement value Dx, the measured value Vx speed monitors whether the region II of a main collision avoidance state of FIG. 5, if the normal traveling state, step Q1 From Step Q5, the occurrence of an emergency depressing operation for avoiding the collision of the brake pedal is monitored from the change in the M / C pressure, and the measured values Dx and Vx are in the region II of FIG. Steps Q1 and Q5 are repeated until the collision avoidance state is detected or an emergency stepping operation occurs.

  Next, for example, if the driver does not perform an emergency stepping operation for avoiding the collision of the brake pedal 71 even if the speed of the object ahead of the vehicle has occurred and the vehicle 1 has approached the object in front of the vehicle, The collision avoidance state is detected by Q1, and the process proceeds from Step Q1 to Step Q2, the motor 713 in FIG. 2 is driven and the upstream valve 719 is opened to execute the BA intervention braking control, and the BA automatically intervenes. Will be in the braking state.

  Therefore, even if the driver does not depress the brake pedal 71, the assist pressure for the BA intervention is automatically applied to the wheel cylinders 10F and 10R, and the BA intervenes at the optimal timing to brake the vehicle 1 and While giving priority to braking control, collision is avoided and safety is significantly improved.

  When the driver depresses the brake pedal 71 in the BA intervention state, the corresponding M / C pressure is added and applied to the wheel cylinders 10F and 10R, and the own vehicle 1 decelerates and stops more rapidly as the braking force increases.

By the way, in order to improve the safety by the BA intervention, the host vehicle 1 of the present embodiment has the following function (a). In addition, when further improving safety by BA intervention, the following (b), (c
It is preferable that at least one of the functions of

(A) Standard correction function based on individual differences Since there are individual differences in the determination of the possibility of collision and the operation of the brake pedal 71, depending on the driver, there is a tendency that the operation tends to be delayed. When the braking control for BA intervention is performed at an appropriate timing in consideration of the above, the braking control means has a reference correction function based on the following individual differences.

The reference correction function in everyday operation, and holds the detected time difference between the detection timing of the main collision avoidance state of step Q1 of FIG. 4, the timing at which the driver performs the stepping operation of the BA intervention of the brake pedal, further For example, every time the vehicle 1 is started, an average value of the held time difference (average time difference) is obtained, a distance correction value proportional to the average time difference is calculated, and a speed correction in which the polarity of the average time difference is inverted is calculated. It calculates a value, in the initial setting of step S1 of FIG. 3, each combination of threshold distance Dref read from the storage unit 6, the threshold speed Vref, a main collision threshold line DV of 5 moves upward The state is corrected so that the region II (collision prediction range) is widened, and the state where the collision avoidance state is detected becomes easier as the driver's brake operation is slower.

  This correction makes it possible to detect the collision avoidance state earlier than the standard for a driver who seems to be late in the brake operation, and to perform the BA intervention braking control at an optimal timing considering the characteristics of the driver.

(B) Reference correction function based on sensor recognition level Next, when the recognition level (capture level) of the object ahead of the vehicle by the search sensor 2 is considered low, the measurement accuracy of the search sensor 2 is considered low. In such a case, it is preferable from the viewpoint of safety to perform braking control of BA intervention at an early stage.

  Therefore, when safety is more important, the braking control means is provided with a reference correction function based on the sensor recognition degree, and the threshold distance Dref and the threshold speed Vref are corrected according to the recognition degree of the object ahead of the vehicle by the exploration sensor 2. .

That is, the recognition degree of the object ahead of the vehicle in the exploration sensor 2 is, for example, the degree of variation (blurring) in the reception range of the reflected wave in the case of leather radar, and the contour of the image processing result in the case of a CCD camera. variation (blur) on the order of, by said reference correction function, when the recognition degree is low, depending on the extent, the area II of the threshold line DV moves upward main collision avoidance state of FIG. 5 The threshold distance Dref and the threshold speed Vref are corrected so as to widen, and the detection criterion of the collision avoidance state is lowered.

  Specifically, for example, as shown in FIG. 3, a reference correction step S6 based on the degree of broken line sensor recognition is provided between steps S3 and S4. By this step S6, for example, the detection of the exploration sensor 2 in the measurement of step S2 is performed. Based on the determination of the degree, the threshold distance Dref and the threshold speed Vref of each combination read from the storage unit 6 are corrected according to the determined recognition degree.

  Then, by performing the reference correction according to the sensor recognition, the comparison result in step S4 takes into consideration the recognition degree of the exploration sensor 2, and if the recognition degree is low, it is necessary in step Q1 of FIG. The detection criteria for the collision state are relaxed, and the BA becomes easier to intervene to further improve the safety.

(C) BA Intervention Amount Correction Function This correction function increases or decreases the BA intervention amount in accordance with the detection state by detecting the collision avoidance state, and is provided in the braking control means of the ECU 5.

  Specifically, for example, step Q6 for correcting the BA intervention amount indicated by a broken line is provided after step Q1 in FIG. 4, and for example, the degree of the collision avoidance state detected in step Q1 (the degree of the detection state), in other words, the collision The assist pressure setting value is corrected to increase or decrease in proportion to the degree of possibility.

  Therefore, in the BA intervention of step Q2 in FIG. 4, the higher the possibility of a collision, the higher the assist pressure of the BA intervention, the braking force increases, and the safety is further improved.

Next, automatically or example brake mechanism 7 in FIG. 2, subject to lighting that controls the braking state BA intervened stop lamp 8 will be described with reference to the flowchart for explaining the operation of Figure 7.

In the example of this, a situation requiring collision avoidance between the vehicle forward object, i.e., upon detection of the main collision avoidance state of the, to indicate an intention by the driver to brake put the foot on the brake pedal Intervene BA in the condition.

Therefore, in this example executes a program BA intervention control step Q1~Q7 of Figure 7 in place of 4 by ECU 5, the braking control means ECU 5 is, by the detection of a substantial collision avoidance state, the vehicle 1 the stop lamp lighting operation conditions, that controls the brake mechanism 2 to the braking state BA intervened.

  Specifically, as shown in FIG. 7, step Q7 for detecting lighting of the stop lamp 8 is provided after step Q1, and when the collision avoidance state is detected at step Q1, the stop lamp switch 4 is turned on at step Q7. Detects the presence or absence of contact signals.

  The driver's intention to apply the brake by placing his / her foot on the brake pedal 71 generates a contact signal of the stop lamp switch 4 indicating the lighting operation of the stop lamp 8 regardless of the depression amount of the brake pedal. Based on the detection of this signal, BA intervention braking control is performed in step Q2 of FIG.

  Therefore, even if the driver's brake pedal 71 is depressed a little, based on the detection of the driver's intention to apply the brake, the BA intervention braking state occurs simultaneously with the lighting of the stop lamp 8, and the driver's intention is respected and optimized. Safety can be improved by ensuring that the BA intervenes at a proper timing.

  Incidentally, in this example as well, the above-mentioned (a) reference correction function based on individual differences is provided. Furthermore, safety is further improved by providing at least one of (b) a reference correction function based on the degree of sensor recognition and (c) a BA intervention amount correction function.

  Next, another example of controlling the brake mechanism 7 in FIG. 2 to the braking state in which the BA has intervened on the condition that the stop lamp 8 is turned on automatically or on condition of the lighting of the stop lamp 8 will be described with reference to FIG. This will be described with reference to a flowchart for explanation.

  In this example, the possibility of collision between the host vehicle and the object ahead of the host vehicle is detected from the travel prediction of both vehicles in consideration of the distance between the host vehicle and the preceding vehicle, the relative speed of the preceding vehicle, and the like.

Therefore, the braking device of this example is different from the braking device of the above example and the other examples. The ECU 5 executes the BA intervention control program of steps S11 to S17 or S11 to S18 of FIG. 9 instead of FIG. is that provided with the offset ratio estimating means in ECU 5, one technique.

(Iii) Offset Rate Estimating Means This means is used to calculate the laterality between the host vehicle 1 and the preceding vehicle 11 at the predicted collision position from, for example, the predicted travel path L of FIG. 3 is formed by steps S11 to S16 in FIG. 3. In step S11, the same initial setting as in step S1 in FIG. 3 is performed. In steps S12 and S13, Measurements Dx and Vx are obtained by performing the same measurement as in steps S2 and S3 of FIG.

  Further, in step S14, for example, from the change tendency of the latest measurement results of the distance Dx and the speed Vx, the position P of the preceding vehicle 11 shown in FIG. 8 at the future times T1, T2, T3,. (T1), P (T2), P (T3),..., P (Tn) are obtained, and a travel prediction trajectory L of the preceding vehicle 11 connecting the positions P (T1) to P (Tn) is obtained and estimated. .

  Here, the position P (Tn) is a predicted position where the preceding vehicle 11 and the host vehicle 1 collide with each other as shown in FIG. 8 when traveling as it is, and the preceding vehicle 11 at the predicted position P (Tn) is determined in step S14. The offset rate OFx indicating the magnitude of the collision possibility is obtained and estimated by dividing the length Y in which the vehicle 1 and the vehicle 1 overlap in the lateral direction (vehicle width direction) by the vehicle width of the vehicle 1.

  Further, in step S16, the estimated offset rate OFx is compared with the threshold offset rate OFr of the collision prediction range stored in the storage unit 6 in FIG. 1 instead of the threshold distance Dref and the threshold velocity Vref.

  The offset rate OFr is an offset rate that is highly likely to cause a collision and requires a collision avoidance operation, and is set by an experiment or the like.

  Then, until the ignition switch of the host vehicle 1 is turned off, the process returns from step S16 to step S11 via step S17, and the process of FIG. 8 is repeated.

  Next, the ECU 5 of this example includes braking control means similar to the braking control means formed by, for example, steps Q1 to Q5 or steps Q1 to Q6 of FIG. 4, and the step Q1 of FIG. If a collision avoidance state in which there is a high possibility of collision between the host vehicle 1 and the preceding vehicle is detected from the comparison of the offset rates OFx and OFr, the first and second steps are performed in steps Q2 to Q5 or steps Q2 to Q6 in FIG. As in the case of the embodiment, BA can be automatically intervened to avoid a collision and to significantly improve safety.

  By the way, also in this example, safety is further improved by providing the above-mentioned (a) reference correction function based on individual differences, (b) reference correction function based on sensor recognition degree, and (c) BA intervention amount correction function. To do.

Next, the control according to the embodiment of the present invention will be described with reference to FIG. 5 and the flowchart for explaining the operation of FIG.

  In the present embodiment, when the BA intervention is necessary due to the detection of the collision avoidance state, the braking state in which the BA intervenes the brake mechanism 7 in FIG. 2 on condition that the stop lamp 8 is turned on automatically. Instead of controlling the brake pedal automatically, the detection criterion for emergency depression of the brake pedal is lowered on condition that the stop lamp 8 is lit, so that the BA intervenes early with respect to the depression of the brake pedal. Ensure that the BA intervenes at the right time.

  For this reason, the braking device of the present embodiment is different from the braking devices of the above examples in that the ECU 5 executes the BA intervention control program in steps Q11 to Q17 in FIG. 10 instead of FIG. The emergency depressing of the brake pedal 71 is performed automatically upon detection of a collision avoidance state or when the stop lamp is lit (indicating that the driver intends to brake with the foot on the brake pedal 71). The detection criteria for the operation, specifically the detection criteria for the depression amount and the depression speed of the brake pedal 71 that intervenes in the BA, are read from the storage unit 6 by the initial settings in step S1 in FIG. 3 and step S11 in FIG. It is a point to lower from the detection standard of normal BA intervention (standard).

  Then, steps Q11 to Q16 in FIG. 10 substantially correspond to steps Q1 to Q6 in FIG. 4. When the collision avoidance state is detected in step Q11, the process proceeds to step Q15 via steps Q16 and Q17. By detecting an emergency stepping operation from the stepping amount and stepping speed of the brake pedal 71 by Q15, BA is intervened by step Q12.

By the way, when the depression amount and depression speed of the detection criterion for normal BA intervention are ST0 and dST0, and the depression amount and depression velocity of the detection criterion for BA intervention when a collision avoidance state is detected are STe and dSTe, FIG. In the traveling state of the region I, the detection standard for the emergency depression operation of the brake pedal 71 is set to the depression amount ST0 and the depression speed dST0 of the detection criterion for the normal BA intervention read from the storage unit 6, and the collision avoidance state is required. In the traveling state of area II, at step Q17, the detection criteria for the emergency depression operation of the brake pedal 71 are respectively lowered by a set amount to switch the depression amount STe and the depression speed to dSTe.

  Therefore, when an emergency stepping operation occurs for some reason during normal traveling in the state of the region I, the process proceeds from step Q11 to step Q15, and in step S15, the stepping amount ST0 and the stepping speed dST0 are used as a reference. The necessity / unnecessity of BA intervention is detected and judged, and in step Q12, normal BA intervention is performed as necessary under the same conditions as in the above example.

  Further, when the traveling state of the region II is entered, the process proceeds from step Q11 to step S17 via step Q16. After this step S17, the depression amount and the depression speed of the brake pedal 71 are reduced to STe, dSTe, In step Q15, the presence or absence of an emergency stepping operation is detected with reference to the stepping amount STe and the stepping speed dSTe. When the operation is detected, BA intervention for emergency avoidance is performed in step Q12.

  In this case, since the depression amount and depression speed of the BA intervention detection standard are lowered to STe and dSTe, the emergency depression operation is detected even when the depression of the brake pedal 71 is shallower than in the case of the normal BA intervention, and the brake mechanism 7 is promptly operated. It is possible to improve the safety by ensuring that the BA intervenes at an optimal timing while maintaining the original function of the BA that is operated by depressing the brake pedal 71 in the braking state in which the BA intervenes.

Incidentally, even in the case of performing the control of this embodiment includes a reference correction function based on the above (a) individual differences, as the braking operation of the vehicle driver is slow, region II (collision prediction range of a substantial collision state ), The threshold distance Dref and the threshold speed Vref are corrected, the detection criterion of the collision avoidance state is lowered, the direction is made easier to detect the collision avoidance state, and the slow speed of the driver's brake operation is also taken into consideration. Monitor and detect possible collisions. Furthermore, safety is further improved by providing at least one of (b) a reference correction function based on the degree of sensor recognition and (c) a BA intervention amount correction function.

  In addition, for example, a step similar to step Q7 in FIG. 6 is provided between step Q11 and step Q16 in FIG. 10, and when the collision avoidance state is detected, the stoppage of the stop lamp 8 is used as a condition. The presence or absence of an emergency stepping operation may be detected based on STe and the stepping speed dSTe.

  Further, the ECU 5 may detect the collision-required avoidance state by any of the comparison of the traveling state detection unit in FIG. 3 and the offset rate estimation unit in FIG.

  Next, in the present embodiment, step Q17 in FIG. 10 reduces the detection reference stepping amount and stepping speed by the respective set amounts regardless of the magnitude of the collision possibility in the collision avoidance necessary state. dSTe, for example, in step Q17, for each of the detection reference depression amount and depression velocity, a set amount proportional to the magnitude of the collision possibility determined by comparing step S4 in FIG. 3 and step S11 in FIG. The detection characteristics of the emergency depressing operation may be varied according to the degree of possibility of collision.

In this case, the simplest, the in FIG. 11 if example embodiment (a), holding depression amount STe, the data of the characteristic diagram for the measured value Dx of the distance depression speed dSTe in the storage section 6 of the (b), a main collision avoidance When the state is detected, the stepping amount STe and the stepping speed dSTe may be set based on the distance measurement value Dx at that time. Note that Dmax in the figure is a limit distance that is determined to be a collision-avoidance state, and varies depending on the measured speed value Vx and the like.

  In this case, there is an advantage that safety and operability are improved without giving the driver an uncomfortable feeling of operability.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit thereof. For example, the brake actuator 7 is different from that shown in FIG. A configuration may be used, and a processing procedure, each reference value, and the like of the ECU 5 may be different from those in the above embodiment.

  Of course, the present invention can also be applied to the case where the pressurizing mechanism of the BA system is a hydraulic pump type having a configuration different from that of the above-described embodiment and when the BA system is not a hydraulic pump type.

  By the way, the exploration sensor 2 and the wheel speed sensor 3 shown in FIG. 1 can also be applied to the so-called follow-up control.

1 is a block diagram of an embodiment of the present invention. It is a detailed block diagram of the brake mechanism (brake actuator) of FIG. It is a flowchart for operation | movement description of FIG. It is a flowchart for operation | movement description of an example of the brake assist intervention of FIG. It is explanatory drawing of the combination of the distance of the collision prediction range of FIG. 1, and speed (relative speed) . It is a figure of the driving | running | working state for operation | movement description of FIG. 6 is a flowchart for explaining the operation of another example of the brake assist intervention of FIG. 1. It is an illustration of a predicted travel trajectories Atorei of the present invention. 7 is a flowchart for explaining the operation of still another example of the brake assist intervention of FIG. 1. It is a flowchart explaining control of embodiment of this invention. (A), (b) is explanatory drawing in the case of varying the depression amount and depression speed of the brake pedal of embodiment of this invention.

1 Vehicle 5 ECU
7 Brake actuator 8 Stop lamp 71 Brake pedal

Claims (2)

Since the combination of the distance between the traveling vehicle and the vehicle front object and the measured value of the relative speed of the vehicle front object with respect to the vehicle is a combination of the set collision prediction range, the vehicle and the vehicle When a collision avoidance state that increases the possibility of collision with an object ahead is detected, the brake mechanism of the host vehicle is controlled to a braking state in which the brake assist intervenes regardless of whether the driver depresses the brake pedal. A vehicle braking method comprising :
In daily operation, based on the average value of the time difference between the timing at which the detection timing and the driver of the main collision avoidance state performs a depression operation of the brake pedal of the brake assist intervention as driver brake operation is slow, spread the collision prediction range A vehicle braking method that makes it easy to detect the collision avoidance state. Since the combination of the measured value of the distance between the traveling vehicle and the object in front of the vehicle and the measured value of the relative speed of the object in front of the vehicle is a combination of the set collision prediction range, When a collision avoidance state in which the possibility of collision between the vehicle and the object in front of the host vehicle becomes high is detected, the brake mechanism of the host vehicle is braked by the brake assist regardless of whether the driver depresses the brake pedal. A vehicle braking device for controlling the state ,
In daily operation, based on the average value of the time difference between the timing at which the detection timing and the driver of the main collision avoidance state performs a depression operation of the brake pedal of the brake assist intervention as driver brake operation is slow, spread the collision prediction range A vehicle braking apparatus comprising a correction function that facilitates detection of the collision-avoidance state.

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