JP2016055768A - Brake control device - Google Patents

Brake control device Download PDF

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Publication number
JP2016055768A
JP2016055768A JP2014183790A JP2014183790A JP2016055768A JP 2016055768 A JP2016055768 A JP 2016055768A JP 2014183790 A JP2014183790 A JP 2014183790A JP 2014183790 A JP2014183790 A JP 2014183790A JP 2016055768 A JP2016055768 A JP 2016055768A
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vehicle
brake
collision
towed vehicle
towed
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JP6481196B2 (en
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高志 目崎
Takashi Mesaki
高志 目崎
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三菱自動車工業株式会社
Mitsubishi Motors Corp
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Abstract

A brake control device that prevents a rear-end collision of a towed vehicle during automatic braking is provided. A brake device 17 that brakes a tow vehicle 10, a brake device 31 that brakes a towed vehicle 30 pulled by the tow vehicle 10, and a control unit that controls the brake device 17 and the brake device 31 are provided. , A first collision risk threshold for avoiding a collision of the tow vehicle 10 with a front obstacle at a first known maximum deceleration of the tow vehicle 10, and until the towed vehicle 30 collides with the tow vehicle 10. The rear collision risk time is compared, and if the rear collision risk time is smaller than the first collision risk threshold, the second maximum deceleration of the towed vehicle 30 is set as the deceleration of the towed vehicle 10 and the towed vehicle 30. Then, braking is performed by the brake device 17 and the brake device 31. [Selection] Figure 2

Description

  The present invention relates to a tow vehicle and a brake control device that controls a brake of a towed vehicle towed by the tow vehicle.

  A technique is known in which the acceleration of the towed vehicle is compared with the acceleration of the towed vehicle, and if the latter acceleration is greater than the former acceleration, the electromagnetic brake of the towed vehicle is operated to brake the towed vehicle ( Patent Document 1).

Japanese Patent No. 4654420

  Tow vehicles, particularly large tow vehicles, are highly susceptible to collisions and require automatic braking. However, at the time of towing, which is the main use of large tow vehicles, there is no point in automatically braking only the own vehicle (tow vehicle), and there is a risk that the towed vehicle will collide with the tow vehicle unless braking of the towed vehicle is also considered. There is. Further, even if the towed vehicle is equipped with an automatic brake, the front is always a towed vehicle, so it is not possible to determine the risk of collision with an obstacle ahead. Thus, the tow vehicle needs an automatic brake in consideration of the braking of the towed vehicle.

  The present invention has been made in view of the above problems, and an object thereof is to provide a brake control device that prevents a rear-end collision of a towed vehicle during automatic braking.

A brake control device according to a first invention for solving the above-described problem is
A first brake device for braking the tow vehicle;
A second brake device for braking the towed vehicle pulled by the tow vehicle;
Control means for controlling the first brake device and the second brake device;
The control means includes
A first collision risk threshold for the tow vehicle to avoid a collision with the front obstacle at a known first maximum deceleration of the tow vehicle; and until the towed vehicle collides with the tow vehicle. Compare the rear-end collision danger time,
When the rear collision risk time is smaller than the first collision risk threshold, a second maximum deceleration of the towed vehicle is set as a deceleration of the towed vehicle and the towed vehicle, and the first brake The brake is performed by the device and the second brake device.

A brake control device according to a second invention for solving the above-mentioned problem is as follows.
In the brake control device according to the first invention,
The control means includes
When the collision risk time is equal to or greater than the first collision risk threshold, the first maximum deceleration is set as the deceleration of the towed vehicle and the towed vehicle, and the first brake device and the Brake is performed by the second brake device.

A brake control device according to a third invention for solving the above-described problem is
In the brake control device according to the first or second invention,
Weight detection means for detecting the weight of the towed vehicle;
Vehicle speed detecting means for detecting the vehicle speed of the towed vehicle,
The control means includes
While the towed vehicle and the towed vehicle are traveling, maximum braking is performed using only the second brake device, and a vehicle speed change during the braking is acquired by the vehicle speed detecting means, and the acquired vehicle speed The second maximum deceleration is obtained based on a change, a known first weight of the towed vehicle, and a second weight of the towed vehicle detected by the weight detecting means. .

A brake control device according to a fourth invention for solving the above-described problem is
In the brake control device according to any one of the first to third inventions,
A relative speed detecting means for detecting a relative speed between the tow vehicle and the front obstacle;
An inter-vehicle distance detecting means for detecting an inter-vehicle distance between the towed vehicle and the towed vehicle;
The control means includes
Obtaining the first collision risk threshold based on the relative speed detected by the relative speed detecting means and the first maximum deceleration;
The risk of rear-end collision is obtained based on the inter-vehicle distance detected by the inter-vehicle distance detecting means, the first maximum deceleration, and the second maximum deceleration.

A brake control device according to a fifth aspect of the present invention for solving the above problem is
In the brake control device according to the fourth invention,
A relative distance detecting means for detecting a relative distance between the tow vehicle and the front obstacle;
The control means includes
Based on the relative distance detected by the relative distance detection unit and the relative speed detected by the relative speed detection unit, a collision prediction time until the tow vehicle collides with the front obstacle is obtained.
Based on the relative speed detected by the relative speed detection means and the second maximum deceleration, the tow vehicle avoids a collision with the front obstacle with the second maximum deceleration. Find the collision risk threshold of 2,
When the collision risk time is smaller than the first collision risk threshold, and the predicted collision time is less than or equal to the second collision risk threshold, the second maximum is set as the deceleration of the towed vehicle and the towed vehicle. A deceleration is set and braking is performed by the first brake device and the second brake device.

A brake control device according to a sixth aspect of the present invention for solving the above problem is as follows.
In the brake control device according to the fourth invention,
A relative distance detecting means for detecting a relative distance between the tow vehicle and the front obstacle;
The control means includes
Based on the relative distance detected by the relative distance detection unit and the relative speed detected by the relative speed detection unit, a collision prediction time until the tow vehicle collides with the front obstacle is obtained.
When the collision risk time is equal to or greater than the first collision risk threshold, and the predicted collision time is equal to or less than the first collision risk threshold, the deceleration of the towed vehicle and the towed vehicle is determined as the first collision risk. A maximum deceleration is set and braking is performed by the first brake device and the second brake device.

  According to the present invention, it is possible to prevent a rear-end collision of a towed vehicle during automatic braking. Even if the rear-end collision cannot be prevented, the damage can be reduced.

It is the schematic explaining the automatic brake of the tow vehicle and towed vehicle in this invention. It is a block diagram which shows the brake control apparatus which concerns on this invention. FIG. 3 is a first half of a flowchart for explaining a learning procedure of maximum deceleration performed by the brake control device shown in FIG. 2. FIG. 3 is a latter half of a flowchart for explaining a maximum deceleration learning procedure performed by the brake control device shown in FIG. 2. It is a flowchart explaining the procedure of the rear-end collision prevention implemented with the brake control apparatus shown in FIG. It is a graph which compares the conventional and this invention, (a) is a graph at the time of the conventional automatic brake, (b) is a graph at the time of the automatic brake of this invention. It is a time chart which compares the conventional and this invention, (a) is a time chart of the conventional automatic brake, (b) is a time chart of the automatic brake of this invention.

  Hereinafter, an embodiment of a brake control device according to the present invention will be described with reference to FIGS.

(Example 1)
FIG. 1 is a schematic diagram for explaining automatic braking of a tow vehicle and a towed vehicle in the present embodiment. FIG. 2 is a block diagram showing the brake control device of this embodiment. FIGS. 3 and 4 are flowcharts for explaining the learning procedure of the maximum deceleration executed by the brake control device shown in FIG. FIG. 5 is a flowchart for explaining the procedure for preventing a rear-end collision performed by the brake control apparatus shown in FIG. FIG. 6 is a graph comparing the prior art with the present invention, FIG. 6 (a) is a graph during conventional automatic braking, and FIG. 6 (b) is a graph during automatic braking according to the present invention. . 7 is a time chart for comparing the prior art with the present invention, FIG. 7 (a) is a time chart for a conventional automatic brake, and FIG. 7 (b) is a time chart for the automatic brake of the present invention. is there.

  First, with reference to FIG. 1, the outline of the automatic brake of the tow vehicle and the towed vehicle in the present embodiment will be described.

  In the present embodiment, the tow vehicle 10 has a tow device 40 for towing the towed vehicle 30 and a brake control device to be described later. The brake control device is based on a front obstacle sensor 11 (for example, a radar or the like) to be described later. When the obstacle 50 is detected, automatic braking is performed in the host vehicle (the towing vehicle 10) according to the procedure described later, and a brake instruction is given to the towed vehicle 30 to prevent a rear-end collision of the towed vehicle 30. Yes.

  Next, the configuration of the brake control device of this embodiment will be described with reference to FIG.

  The brake control device according to the present embodiment includes a front obstacle sensor 11 (relative speed detection means and relative distance detection means) that detects a relative distance and a relative speed with an obstacle 50 ahead of the tow vehicle 10, and a tow vehicle 10. A vehicle speed sensor 12 that detects the vehicle speed, a yaw sensor 13 that detects the yaw rate (lateral acceleration / deceleration) of the tow vehicle 10, and a brake that detects the brake state of the tow vehicle 10 (for example, on / off of the brake, brake pressure, etc.) The sensor 14 includes a traction sensor 15 that detects a traction state (presence / absence of the towed vehicle 30), and a rear camera 16 (an inter-vehicle distance detection unit) that detects a relative distance (an inter-vehicle distance) from the towed vehicle 30. ing.

  In addition, the brake control device of the present embodiment includes a brake device 17 (first brake device) that brakes the tow vehicle 10, a towed vehicle communication device 18 that communicates with the towed vehicle 30, the above-described sensor, and the like. Information from a towed vehicle 30 (to be described later) is input together with the information from the main control device 20 to give a deceleration instruction to be described later.

  The main control device 20 (control means) has a maximum deceleration calculation unit 21 and a risk determination unit 22.

  Although the details will be described later, the maximum deceleration calculation unit 21 calculates and learns the maximum deceleration (second maximum deceleration G2) of the towed vehicle 30 based on the input information, and learns the towed vehicle. The time until the vehicle 30 collides with the tow vehicle 10 (risk collision time T2) is calculated.

  Although the details will be described later, the risk determination unit 22 calculates a predicted time (collision predicted time TTC) until it collides with the obstacle 50 ahead based on the input information, and the calculated predicted time. When it is less than the danger threshold (first collision danger threshold TTCL or second collision danger threshold TTCL2), that is, when it is determined that there is a danger of collision with the obstacle 50 or rear-end collision of the towed vehicle 30, the collision Alternatively, a deceleration instruction to the brake device 17 is given at a deceleration that prevents a rear-end collision, and a deceleration instruction to a brake device 31 of a to-be-towed vehicle 30 (to be described later) is given via the to-be-trained vehicle communication device 18.

  Further, the brake control device of the present embodiment includes a brake device 31 (second brake device) for braking the towed vehicle 30, a vehicle speed sensor 32 (vehicle speed detecting means) for detecting the vehicle speed of the towed vehicle 30, A brake sensor 33 for detecting the brake state of the tow vehicle 30 (for example, brake on / off, brake pressure, etc.), and a weight sensor 34 (weight detection means) for detecting the weight of the towed vehicle 30 including the load. The information from these sensors is input to the main controller 20 (maximum deceleration calculation unit 21) via the towed vehicle communication device 18.

  Thus, the towed vehicle communication device 18 transmits the vehicle speed, the brake state, and the weight from the vehicle speed sensor 32, the brake sensor 33, and the weight sensor 34 to the main control device 20 (maximum deceleration calculation unit 21) and is dangerous. A deceleration instruction (for example, deceleration, brake pressure, etc.) from the determination unit 22 is transmitted to the brake device 31.

  The sensors described above may be changed to other sensors as long as they have equivalent functions. For example, the rear camera 16 may be changed to a radar or the like as long as the distance between the rear vehicle 16 and the towed vehicle 30 can be detected.

  Next, referring to FIGS. 3 and 4 together with FIGS. 1 and 2, the learning procedure of the maximum deceleration executed by the brake control device of this embodiment will be described. Here, as shown in FIG. 1, the relative distance between the tow vehicle 10 and the obstacle 50 is L1, the relative speed is V1, and the relative distance (inter-vehicle distance) between the tow vehicle 10 and the towed vehicle 30 is L2. The relative speed is assumed to be V2.

(Step S1)
The tow vehicle 10 (main control device 20) establishes communication with the towed vehicle 30 via the towed vehicle communication device 18 when the towed vehicle 30 is connected to the tow device 40. The communication may be wired or wireless.

(Step S2)
The tow vehicle 10 (main control device 20) acquires the weight M of the towed vehicle 30 via the towed vehicle communication device 18. This weight M is the weight of the towed vehicle 30 including the load.

(Step S3)
The tow vehicle 10 (main control device 20) confirms whether or not the change in the weight M acquired this time is greater than a certain value from the weight M obtained during the previous learning (for example, during the previous travel). Proceed to step S4. This means that if there is a certain change, the previous learning is reset and new learning is performed. On the other hand, if the change is less than a certain value, the series of maximum deceleration learning procedures is terminated. This means that the calculated values (maximum deceleration G2, rear collision danger time T2), which will be described later, are the same as the previous time.

(Step S4)
The tow vehicle 10 (main control device 20) issues a maximum deceleration instruction to the brake device 31 of the towed vehicle 30 via the towed vehicle communication device 18 at a predetermined timing, and the towed vehicle 30 is subjected to the maximum brake. multiply.

  Subsequent steps S5 to S7, including step S4, are procedures for obtaining the maximum deceleration G2 of the towed vehicle 30. In order to obtain the maximum deceleration G2, only the towed vehicle 30 has a maximum. It is necessary to apply the brake. Usually, since the maximum brake is rarely applied, the maximum deceleration G2 is obtained by applying the maximum brake to the towed vehicle 30 in the following cases (1) to (4) as the predetermined timing for applying the maximum brake. To get.

(1)
When applying a normal brake, the brake device 17 of the tow vehicle 10 is not used, and the maximum brake is applied only to the brake device 31 of the towed vehicle 30. In this case, since it is necessary to brake both the towed vehicle 10 and the towed vehicle 30 by the brake device 31 of the towed vehicle 30, the braking force of the towed vehicle 30 can be used more than usual.

(2)
When there are a plurality of brake devices 31 of the towed vehicle 30, a maximum deceleration G2 per one is obtained by partially using the plurality of brake devices 31 of the towed vehicle 30, and the sum is calculated. Thus, the maximum deceleration G2 by all the brake devices 31 is acquired.

(3)
If the towed vehicle 30 has not yet stopped immediately after the towed vehicle 10 is stopped by the brake, only the towed vehicle 30 is braked.

(4)
When the tow vehicle 10 starts, control is performed by an ABS (Antilock Brake System) so that the towed vehicle 30 can be braked at maximum.

(Step S5)
The tow vehicle 10 (main control device 20) monitors the vehicle speed, the yaw rate, and the brake pressure using the vehicle speed sensor 12, the yaw sensor 13, and the brake sensor 14 while the towed vehicle 30 is braked.

(Step S6)
The tow vehicle 10 (main control device 20) uses the rear camera 16, the vehicle speed sensor 12, and the vehicle speed sensor 32 to acquire the relative distance L2 and the relative speed V2 between the tow vehicle 10 and the towed vehicle 30. The relative distance L2 is acquired using the rear camera 16. The relative speed V <b> 2 may be acquired using the rear camera 16, or may be acquired using the vehicle speed sensor 12 and the vehicle speed sensor 32.

(Step S7)
During braking of the towed vehicle 30, the vehicle speed sensor 12, the yaw sensor 13, and the brake sensor 14 are used to “decelerate constantly”, “no lateral acceleration / deceleration”, and “tow vehicle 10 If there is no brake, the process proceeds to step S8, and if any of the conditions "deceleration is not constant", "there is lateral acceleration / deceleration", or "the brake of the tow vehicle 10 is present" Since it is not suitable for the calculation of the deceleration G2, the process returns to step S4. Here, if the towed vehicle 30 decelerates other than the brake device 17 or has a curve, it is determined that it is not suitable for calculating the maximum deceleration G2.

(Step S8)
The tow vehicle 10 (main control device 20) calculates the maximum deceleration G2 of the towed vehicle 30. Here, the weight m of the towed vehicle 10 is known, the weight M of the towed vehicle 30 is acquired in step S2, and the vehicle speed change ΔV due to the maximum brake of the towed vehicle 30 is detected by the vehicle speed sensor 32. Therefore, the maximum deceleration G2 can be obtained using the following equation using the weights m and M and the vehicle speed change ΔV.

  G2 = ΔV × (m + M) / M

(Step S9)
The tow vehicle 10 (main control device 20) calculates the rear collision risk time T2 until the towed vehicle 30 collides during the maximum brake. Here, the relative distance L2 is acquired using the rear camera 16 in step S6, the maximum deceleration G1 (first maximum deceleration) of the tow vehicle 10 is known, and the maximum deceleration G2 is determined in step S8. Therefore, using the relative distance L2 and the maximum decelerations G1 and G2, the rear-end collision danger time T2 can be obtained using the following equation.

T2 = (2 × L2 / (G1-G2)) 1/2

  However, when G1 = G2, T2 is treated as “∞”, and when G1 <G2, T2 is an imaginary number. In this case, T2 is treated as “∞”.

  In this way, a series of learning procedures for the maximum deceleration G2 is completed, whereby the tow vehicle 10 (main control device 20) learns and learns the maximum deceleration G2 of the towed vehicle 30 being towed. Based on the maximum deceleration G2, the rear-end collision danger time T2 is obtained. This is because even if the braking force of the towed vehicle 30 at the time of maximum braking is known, the maximum deceleration G2 varies depending on the weight M of the towed vehicle 30. Therefore, the maximum deceleration G2 is determined by the learning procedure. Learning.

  Next, referring to FIG. 5 together with FIG. 1 and FIG. 2, a procedure for preventing a rear-end collision performed by the brake control device of the present embodiment will be described.

(Step S21)
The tow vehicle 10 (main control device 20) uses the front obstacle sensor 11 to obtain the relative distance L1 and the relative speed V1 between the tow vehicle 10 and the front obstacle 50.

(Step S22)
The tow vehicle 10 (main control device 20) calculates the predicted collision time TTC with the obstacle 50 ahead using the relative distance L1 and the relative speed V1 acquired in step S21.

  TTC = L1 / V1

(Step S23)
The first collision risk threshold value TTCL of the tow vehicle 10 and the rear collision risk time T2 of the towed vehicle 30 are compared. If T2 ≧ TTCL, the process proceeds to step S24. If T2 ≧ TTCL is not satisfied, that is, T2 <TTCL. Advances to step S25. This first collision risk threshold value TTCL is defined by TTCL = V1 / G1 using the relative vehicle speed V1 between the towing vehicle 10 and the obstacle 50 ahead and the known maximum deceleration G1 of the towing vehicle 10. Yes, this corresponds to the shortest time for avoiding a collision with the obstacle 50 ahead by the brake of the maximum deceleration G1.

(Step S24)
In the case of T2 ≧ TTCL, in other words, even if the vehicle is decelerated at the maximum deceleration G1 of the tow vehicle 10, the maximum deceleration G2 of the towed vehicle 30 is equal to or greater than the maximum deceleration G1, so that the towed vehicle 30 is towed. If there is no risk of collision with the vehicle 10, it is further checked whether there is a risk of collision with the obstacle 50 ahead, that is, whether TTCL ≧ TTC. If TTCL ≧ TTC, step S26 is performed. If TTCL ≧ TTC is not satisfied (TTCL <TTC), the process returns to step S21.

(Step S25)
When T2 ≧ TTCL is not satisfied, that is, when T2 <TTCL, in other words, when the vehicle is decelerated at the maximum deceleration G1 of the tow vehicle 10, the maximum deceleration G2 of the towed vehicle 30 is less than the maximum deceleration G1. If there is a possibility that the towed vehicle 30 may collide with the towed vehicle 10, it is further checked whether there is a risk of a rear-end collision of the towed vehicle 30, that is, whether TTCL2 ≧ TTC. Advances to step S27, and when TTCL2 ≧ TTC is not satisfied (when TTCL2 <TTC), the process returns to step S21.

  This second collision risk threshold value TTCL2 is defined by TTCL2 = V1 / G2 using the relative vehicle speed V1 between the tow vehicle 10 and the front obstacle 50 and the maximum deceleration G2 of the towed vehicle 30. This corresponds to the shortest time for avoiding the collision with the obstacle 50 ahead by the brake of the maximum deceleration G2.

(Step S26)
When TTCL ≧ TTC, the predicted collision time TTC is equal to or shorter than the first collision risk threshold value TTCL, and there is a risk that the tow vehicle 10 will collide with the obstacle 50 ahead. In this case, as described above, In addition, when T2 ≧ TTCL and T2 ≧ TTCL, there is no danger that the towed vehicle 30 will collide with the towed vehicle 10, so that both the towed vehicle 10 and the towed vehicle 30 are decelerated. A maximum deceleration G1 of 10 is set. Here, since deceleration is performed using the maximum deceleration G1, the start timing of the brake (TTC = TTCL) is later in steps S24 → S26 than in steps S25 → S27.

(Step S27)
When TTCL2 ≧ TTC, the predicted collision time TTC is equal to or shorter than the second collision risk threshold value TTCL2, and there is a risk that the towed vehicle 30 may collide with the towed vehicle 10. As the deceleration, the maximum deceleration G2 of the towed vehicle 30 is set together. Here, since deceleration is performed using the maximum deceleration G2 smaller than the maximum deceleration G1, the brake start timing (TTC = TTCL2) is earlier in the step S25 → S27 than in the case of the step S24 → S26. By this early timing brake, the collision with the obstacle 50 in front of the tow vehicle 10 is also prevented. This timing will be described later with reference to FIGS. 6B and 7B.

  Thus, in steps S26 to S27, the smaller one of the maximum deceleration G1 of the towed vehicle 10 and the maximum deceleration G2 of the towed vehicle 30 is set as the deceleration of the towed vehicle 10 and the towed vehicle 30. Will do.

(Steps S28 to S29)
The tow vehicle 10 (main control device 20) has the deceleration (maximum deceleration G1) set in step S26 or step S27 at the timing (TTC = TTCL or TTCL2) determined in step S24 → S26 or step S25 → S27. Alternatively, G2) is used to instruct the tow vehicle 10 and the towed vehicle 30 to decelerate, and the tow vehicle 10 and the towed vehicle 30 are stopped.

  As described above, when it is determined that there is a collision risk (when the predicted collision time TTC is equal to or less than the first collision risk threshold TTCL) or when it is determined that there is a rear-end collision risk (the predicted collision time TTC is the second collision). When the risk threshold TTCL2 or less), the tow vehicle 10 and the towed vehicle 30 are stopped by the brake device 17 and the brake device 31 at the maximum deceleration G1 or G2, thereby causing a collision with the front obstacle 50 or a towed object. The towing vehicle 10 and the towed vehicle 30 can be stopped without a rear-end collision with the vehicle 30. Even if the collision and rear-end collision cannot be prevented, the damage can be reduced.

  Here, comparison of the conventional automatic braking graph shown in FIG. 6A and the automatic braking graph of this embodiment shown in FIG. 6B will explain the rear-end collision prevention of this embodiment. To do. 6A and 6B, the solid line indicates a change in the distance between the obstacle 50 ahead and the tow vehicle 10, and the dotted line indicates a change in the inter-vehicle distance between the tow vehicle 10 and the towed vehicle 30. Is shown.

As a premise, a case is considered in which the tow vehicle 10 and the towed vehicle 30 are decelerated to avoid the obstacle 50 while traveling at a vehicle speed of 100 km / h (≈27.7 m / s). At this time, the maximum deceleration G1 of the tow vehicle 10 is set to 7 m / s 2 and the maximum deceleration G2 of the towed vehicle 30 is set to 6.5 m / s 2 .

Conventionally, when the tow vehicle 10 avoids the obstacle 50 by automatic braking and the maximum deceleration G1 = 7 m / s 2 is used, the first collision danger threshold TTCL = 3.95 seconds. For example, if the brake is started when the predicted collision time TTC reaches 4 seconds (4 seconds before the collision), the collision with the obstacle 50 can be prevented (see the solid line in FIG. 6A). However, since the towed vehicle 30 uses the maximum deceleration G2 = 6.5 m / s 2 smaller than the maximum deceleration G1, if the inter-vehicle distance (relative distance L2) = 1 m, the rear-end collision danger time T2 = 2 seconds. Even if braking is started when the predicted collision time TTC reaches 4 seconds (4 seconds before the collision), the towing vehicle 10 collides with the towing vehicle 10 before avoiding a collision with the obstacle 50. (See the dotted line in FIG. 6A).

Therefore, in this embodiment, the rear-end collision danger time T2 (2 seconds) is smaller than the first collision danger threshold value TTCL (3.95 seconds), so that both the towed vehicle 10 and the towed vehicle 30 are decelerated. The maximum deceleration G2 of the vehicle 30 = 6.5 m / s 2 is used. In this case, since the second collision risk threshold value TTCL2 = 4.26 seconds, for example, the brake is started when the collision prediction time TTC becomes 4.3 seconds (4.3 seconds before the collision). For example, the collision with the obstacle 50 can be prevented (see the solid line in FIG. 6B), and the tow vehicle 10 and the towed vehicle 30 have the same deceleration, so that the distance between the vehicles is maintained and the towed object is maintained. The rear-end collision of the vehicle 30 can also be prevented (see the dotted line in FIG. 6B).

  If the same thing is done by changing the conditions, the result is as follows.

As a premise, a case where the tow vehicle 10 and the towed vehicle 30 are decelerated to avoid the obstacle 50 while traveling at a vehicle speed of 60 km / h (≈16.7 m / s) is considered. At this time, the maximum deceleration G1 of the tow vehicle 10 is set to 7 m / s 2 and the maximum deceleration G2 of the towed vehicle 30 is set to 6 m / s 2 .

Conventionally, when the tow vehicle 10 avoids the obstacle 50 by automatic braking and the maximum deceleration G1 = 7 m / s 2 is used, the first collision risk threshold value TTCL = 2.38 seconds. For example, if the brake is started when the predicted collision time TTC is 2.4 seconds (2.4 seconds before the collision), the collision with the obstacle 50 can be prevented. However, since the towed vehicle 30 uses a maximum deceleration G2 = 6 m / s 2 smaller than the maximum deceleration G1, if the inter-vehicle distance (relative distance L2) = 1 m, the rear-end collision danger time T2 = 1.41 seconds. Even if the brake is started when the predicted collision time TTC is 2.4 seconds (2.4 seconds before the collision), the tow vehicle 10 will not be able to avoid the collision with the obstacle 50. The rear end hits 10.

Therefore, in the present embodiment, the rear-end collision danger time T2 (1.41 seconds) is smaller than the first collision danger threshold TTCL (2.38 seconds), so that the deceleration of the tow vehicle 10 and the towed vehicle 30 is both The maximum deceleration G2 = 6 m / s 2 of the towed vehicle 30 is used. In this case, since the second collision risk threshold value TTCL2 = 2.78 seconds, for example, the brake is started when the predicted collision time TTC becomes 2.8 seconds (2.8 seconds before the collision). Thus, the collision with the obstacle 50 can be prevented, and the rear-end collision of the towed vehicle 30 can be prevented.

  In addition, since there is a delay in the deceleration instruction of the main control device 20 (danger determination unit 22), or there is a delay until the brake device 17 and the brake device 31 perform the braking after the deceleration instruction, As described above, the first collision risk threshold value TTCL and the second collision risk threshold value TTCL2 are desirably set at a timing earlier than the calculated value as described above.

  FIG. 7A is a conventional time chart corresponding to FIG. 6A described above, and FIG. 7B is a time chart according to the present embodiment corresponding to FIG. 6B described above.

  Conventionally, since automatic braking is performed without taking into account the towed vehicle 30, as shown in FIG. 7A, the first collision risk threshold value TTCL is set as the brake start timing, and the predicted collision time TTC When the vehicle reaches the first collision risk threshold TTCL, the brake switch is turned on, and the tow vehicle 10 decelerates at the maximum speed G1 and the towed vehicle 30 decelerates at the maximum speed G2. As a result, as shown in FIG. 6A, the towed vehicle 30 collides with the towing vehicle 10 before the towing vehicle 10 avoids a collision with the obstacle 50.

  On the other hand, in this embodiment, since automatic braking is performed taking into account the towed vehicle 30, as shown in FIG. 7B, the second collision risk threshold TTCL2 is used as the brake start timing. When the predicted time TTC reaches the second collision risk threshold value TTCL2, the brake switch is turned on, and the tow vehicle 10 and the towed vehicle 30 are decelerated at the same maximum speed G2. As a result, as shown in FIG. 6B, collision with the obstacle 50 can be prevented, and rear-end collision of the towed vehicle 30 can be prevented.

  The present invention is suitable for a towing vehicle equipped with an automatic brake.

DESCRIPTION OF SYMBOLS 10 Tow vehicle 11 Front obstacle sensor 12 Vehicle speed sensor 16 Rear camera 17 Brake device 20 Main control device 30 Towed vehicle 31 Brake device 32 Vehicle speed sensor 34 Weight sensor 40 Tow device 50 Obstacle

Claims (6)

  1. A first brake device for braking the tow vehicle;
    A second brake device for braking the towed vehicle pulled by the tow vehicle;
    Control means for controlling the first brake device and the second brake device;
    The control means includes
    A first collision risk threshold for the tow vehicle to avoid a collision with the front obstacle at a known first maximum deceleration of the tow vehicle; and until the towed vehicle collides with the tow vehicle. Compare the rear-end collision danger time,
    When the rear collision risk time is smaller than the first collision risk threshold, a second maximum deceleration of the towed vehicle is set as a deceleration of the towed vehicle and the towed vehicle, and the first brake And a brake control device that performs braking by the second brake device.
  2. The brake control device according to claim 1, wherein
    The control means includes
    When the collision risk time is equal to or greater than the first collision risk threshold, the first maximum deceleration is set as the deceleration of the towed vehicle and the towed vehicle, and the first brake device and the A brake control device that performs braking by a second brake device.
  3. In the brake control device according to claim 1 or 2,
    Weight detection means for detecting the weight of the towed vehicle;
    Vehicle speed detecting means for detecting the vehicle speed of the towed vehicle,
    The control means includes
    While the towed vehicle and the towed vehicle are traveling, maximum braking is performed using only the second brake device, and a vehicle speed change during the braking is acquired by the vehicle speed detecting means, and the acquired vehicle speed The second maximum deceleration is obtained based on a change, a known first weight of the towed vehicle, and a second weight of the towed vehicle detected by the weight detecting means. Brake control device.
  4. In the brake control device according to any one of claims 1 to 3,
    A relative speed detecting means for detecting a relative speed between the tow vehicle and the front obstacle;
    An inter-vehicle distance detecting means for detecting an inter-vehicle distance between the towed vehicle and the towed vehicle;
    The control means includes
    Obtaining the first collision risk threshold based on the relative speed detected by the relative speed detecting means and the first maximum deceleration;
    The brake control device characterized in that the rear-end collision danger time is obtained based on the inter-vehicle distance detected by the inter-vehicle distance detection means, the first maximum deceleration, and the second maximum deceleration.
  5. The brake control device according to claim 4, wherein
    A relative distance detecting means for detecting a relative distance between the tow vehicle and the front obstacle;
    The control means includes
    Based on the relative distance detected by the relative distance detection unit and the relative speed detected by the relative speed detection unit, a collision prediction time until the tow vehicle collides with the front obstacle is obtained.
    Based on the relative speed detected by the relative speed detection means and the second maximum deceleration, the tow vehicle avoids a collision with the front obstacle with the second maximum deceleration. Find the collision risk threshold of 2,
    When the collision risk time is smaller than the first collision risk threshold, and the predicted collision time is less than or equal to the second collision risk threshold, the second maximum is set as the deceleration of the towed vehicle and the towed vehicle. A brake control device, wherein a deceleration is set and braking is performed by the first brake device and the second brake device.
  6. The brake control device according to claim 4, wherein
    A relative distance detecting means for detecting a relative distance between the tow vehicle and the front obstacle;
    The control means includes
    Based on the relative distance detected by the relative distance detection unit and the relative speed detected by the relative speed detection unit, a collision prediction time until the tow vehicle collides with the front obstacle is obtained.
    When the collision risk time is equal to or greater than the first collision risk threshold, and the predicted collision time is equal to or less than the first collision risk threshold, the deceleration of the towed vehicle and the towed vehicle is determined as the first collision risk. A brake control device, wherein a maximum deceleration is set and braking is performed by the first brake device and the second brake device.
JP2014183790A 2014-09-10 2014-09-10 Brake control device Active JP6481196B2 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000043705A (en) * 1998-07-29 2000-02-15 Mitsubishi Motors Corp Automatic deceleration control device combination vehicle
JP2007084047A (en) * 2005-08-24 2007-04-05 Hino Motors Ltd Automatic brake control device
JP2008183970A (en) * 2007-01-29 2008-08-14 Nissan Diesel Motor Co Ltd Cms brake control device, and its control method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000043705A (en) * 1998-07-29 2000-02-15 Mitsubishi Motors Corp Automatic deceleration control device combination vehicle
JP2007084047A (en) * 2005-08-24 2007-04-05 Hino Motors Ltd Automatic brake control device
JP2008183970A (en) * 2007-01-29 2008-08-14 Nissan Diesel Motor Co Ltd Cms brake control device, and its control method

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