JP2017136960A - Vehicle capable of relaxing collision impact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax comprehensive damage which an own vehicle and an occupant receive due to collision to other object.SOLUTION: The invention is configured to determine possibility of collision of an own vehicle to other object, when it is determined that there is possibility of collision, prompt yaw rotation of the own vehicle, for absorbing a part of collision energy in a collision direction generated due to collision to other object by the yaw rotation of the own vehicle, then disperse acceleration acting the vehicle and an occupant into a linear acceleration in the collision direction and rotation acceleration following to the yaw rotation of the own vehicle which generate no synergy, for relaxing comprehensive damage which the vehicle and the occupant receive due to collision.SELECTED DRAWING: Figure 3

Description

  The present invention relates to mitigating an impact generated in a host vehicle due to a collision with another object.

  When it is predicted that a collision of the own vehicle with another object is inevitable, the steering of the own vehicle may be automatically controlled so that the own vehicle comes into contact with the other object at a portion where the degree of buffering against the impact received by the collision is as high as possible. Is described in Patent Document 1 below.

JP 2005-254923 A

  The impact applied to the host vehicle and its occupant due to the collision of the host vehicle with another object works most severely when it acts linearly along the direction of the collision. If the impact force can be distributed in multiple directions on the spot, the individual impact force will be weakened and the overall damage to the vehicle and passengers can be reduced. One particularly effective way to distribute such impact force in multiple directions is to yaw the vehicle with the energy of the collision.

  Based on the above idea, an object of the present invention is to alleviate comprehensive damage caused to the own vehicle or a passenger due to a collision with another object.

  In order to solve the above problems, the present invention determines the possibility of collision of the own vehicle with another object, and prompts the yaw rotation of the own vehicle when it is determined that there is the possibility. A vehicle with a characteristic is proposed.

  However, since the own vehicle may collide with another object different from the other object due to the yaw rotation of the own vehicle increased by being prompted, the acceleration of the yaw rotation is thereby It may be performed after confirming that there is no possibility of colliding with another object different from the other object.

  As described above, if the vehicle is designed to determine the possibility of a collision of the host vehicle with another object and to promote yaw rotation of the host vehicle when it is determined that there is such a possibility, By absorbing a part of the impact energy in the collision direction caused by the collision by the yaw rotation of the own vehicle and dispersing the acceleration acting on the vehicle and the occupant into the linear acceleration in the collision direction and the rotational acceleration accompanying the yaw rotation of the own vehicle The linear acceleration in the collision direction can be reduced. In this case, in addition to the reduced linear acceleration in the collision direction, the host vehicle and the occupant are subjected to the rotational acceleration associated with the yaw rotation of the host vehicle, but both are accelerations that do not synergize with each other. The total damage caused by the collision can be alleviated, and particularly the total damage received by the passenger who is located near the center of the yaw rotation of the own vehicle can be greatly reduced.

  In addition, the prompting of the yaw rotation is increased by the prompt if it is made after confirming that there is no possibility of the vehicle colliding with another object different from the other object. It is possible to eliminate the inconvenience that the own vehicle collides with another object other than the other object due to the yaw rotation of the own vehicle, and the total damage to the vehicle and the occupant due to the collision can be alleviated.

It is the schematic which illustrates the process in which the own vehicle collides with a preceding vehicle. It is a graph which shows the aspect which the relationship between the braking / driving force and lateral force (side force) which act on the contact point of a wheel, and the aspect which a lateral force changes with the side slip of a wheel. It is a flowchart which shows the response | compatibility control to the vehicle collision by this invention. It is a flowchart which shows the detail of step 60 of FIG. 3 about one Example. It is a flowchart which shows the detail of step 60 of FIG. 3 about another one Example. It is a figure which shows the drive mode of the wheel for making a wheel slip and slide in a 4WD vehicle, a 4-wheel drive force distribution vehicle, and a 2-wheel drive force distribution vehicle. It is a flowchart which shows the control which corrected a part of control shown in FIG.

  Now, as shown in FIG. 1A, it is assumed that the host vehicle 10 is approaching the preceding vehicle 20 from the rear, and the host vehicle approaches the preceding vehicle to a distance that may cause a rear-end collision for some reason. In such a case, many of the drivers will turn the steering wheel so as to avoid the rear-end collision. Therefore, when the own vehicle further approaches the preceding vehicle, the own vehicle 10 is compared with the preceding vehicle 20 as shown in FIG. It is expected that there is some deviation in the lateral direction. The rear-end collision may be avoided by such steering. However, when the rear-end collision by steering cannot be avoided in time, the host vehicle 10 rear-ends the preceding vehicle 20 in a manner that hits the front end as shown in FIG. . In fact, in many rear-end collisions, the rear-end collision car hits the preceding car.

  In this case, the acceleration of the impact acting on the center of gravity of the own vehicle 10 is shifted from the contact portion with the preceding vehicle 20, so that the vehicle 10 is around the contact portion with the preceding vehicle 20 as shown in FIG. Even if the current vehicle is still rotating, a part of the impact energy due to the collision is absorbed by the yaw rotation of the own vehicle, but if the control for promoting the yaw rotation of the own vehicle is performed at this time, more of the impact energy The portion can be absorbed by the yaw rotation of the own vehicle, and damage to the own vehicle and the passenger can be further reduced.

  As is well known, the force acting on the wheel on the road surface is, as shown in FIG. 2A, the force acting between the road surface and the wheel is the coefficient of friction μ between the road surface and the wheel in all directions along the road surface. If the braking / driving force T applied to the wheel increases, the lateral force (side force) F obtained by the wheel becomes 2 of T from the square of μW. Decrease according to the square root of the value minus the power. If a side slip of the wheel is further involved, the braking / driving force T, the side force F, and the side slip angle β are related as shown in FIG. The increase in lateral force due to skidding saturates at βmax of several degrees to 10 degrees. In the figure, a curve 0-Ao shows the correspondence between the side slip angle β and the side force F when the braking / driving force T is zero. A curve 0-A shows the correspondence between the side slip angle β and the side force F when the braking / driving force T is Ta. As can be seen from the correspondence in the figure, Foβ1 and Foβ2 are lateral forces when T is 0 and β is β1 and β2, and Faβ1 and Faβ2 are lateral forces when T is Ta and β is β1 and β2. .

  In the present invention, in consideration of the fact that the lateral force of the wheel changes depending on the braking / driving force T and the side slip angle β as described above, the yaw rotation of the host vehicle 10 in the state shown in FIGS. The control may be executed in the manner shown in the flowchart of FIG.

  In the control shown in FIG. 3, first, in step (S) 10, the speed, position, and traveling direction of an opponent vehicle such as a preceding vehicle that may cause a rear-end collision are estimated. The speed, position, and direction of travel are estimated. Next, in step 30, the road surface friction coefficient is estimated. Based on the data obtained above, in step 40, the possibility of collision of the host vehicle with the opponent vehicle is calculated. Based on the result, step 50 is calculated. It is then determined whether or not a collision is inevitable.

  If the answer to step 50 is yes, that is, if it is determined that a collision is unavoidable regardless of the driver's response, the movement of the opponent's vehicle, or both, the control proceeds to step Proceeding to 60, assuming the state shown in FIG. 1C, the friction coefficient between the road surface and the tire of the host vehicle is reduced, and the host vehicle is in the state shown in FIG. Control for urging the yaw rotation to a greater extent is performed.

  On the other hand, when the answer to step 50 is no, that is, when it is determined that the collision may be avoided depending on the driver's response, the other vehicle's movement, or both, the driver's Care is taken not to control step 60 so as not to interfere with and disturb the response.

  FIG. 4 shows an example of the friction coefficient reduction control for reducing the friction coefficient between the road surface and the tire of the own vehicle in step 60 of FIG. 3 when the own vehicle is a rear wheel drive vehicle or a front wheel drive vehicle. It is a flowchart shown as.

  In this case, first, at step 601, each of the driving wheels is multiplied by the road friction coefficient estimated at step 30 of FIG. A torque Tw that causes slipping due to slippage is estimated. Next, at step 602, a target idling rotational speed is calculated for setting the rotational speed of the driving wheel to a rotational speed suitable for changing the friction with respect to the road surface of the driving wheel from dynamic friction to dynamic friction. In the subsequent step 603, it is determined whether or not the rotational speed of each drive wheel is equal to or less than the target idling rotational speed. If the answer is yes, the control proceeds to step 604 and the Tw estimated in step 601 is reached. The drive wheels are driven with a drive torque whose value is increased by an appropriate increment Δ1. On the other hand, if the answer is no, the control proceeds to step 605, and the drive wheels are driven with a drive torque obtained by reducing the value of Tw estimated in step 601 by an appropriate decrement δ2. In any case, when the drive wheel friction coefficient reduction control is executed as described above, the brake of the non-drive wheel is released in step 606 so that the brake of the non-drive wheel does not hinder the yaw rotation of the vehicle. It is good to keep.

  FIG. 5 shows a friction coefficient reduction control for reducing the friction coefficient between the road surface and the tire of the own vehicle in step 60 of FIG. 3, a four-wheel drive vehicle (4WD vehicle) and a driving force distribution vehicle (torque vectoring vehicle). It is a flowchart shown as one Example about the case of.

  In this case, in step 611, for each of the four wheels (n = 1, 2, 3, 4), the shared load is multiplied by the road surface friction coefficient estimated in step 30 in FIG. By multiplying the conversion coefficient αn, the torque Twn that causes each wheel to slip by slipping is estimated. Next, at step 612, a target idling rotational speed for calculating the rotational speed of each wheel so that the friction with respect to the road surface of each wheel is changed from static friction to dynamic friction is calculated. Next, at step 613, the rotational speed of each wheel is controlled to the target idling rotational speed for each wheel.

  In a four-wheel drive vehicle (4WD vehicle) and a driving force distribution vehicle (torque vectoring vehicle), the drive direction of each wheel can be changed as shown in FIG. 6 in addition to the drive mode during normal forward drive and reverse drive. it can. In addition, even if it is a front-wheel drive vehicle or a rear-wheel drive vehicle, if it is a driving force distribution vehicle, it can change as shown in FIG. The control for sliding the wheel by idling to promote the yaw rotation of the vehicle body does not add an undesirable acceleration to the vehicle by the driving for idling the wheel, and further applies a moment in the yaw rotation direction to the vehicle body. The wheel idling control of FIG. 5 may be performed by incorporating various driving modes as shown in FIG.

  That is, in a 4WD vehicle, the pair of front wheels and the pair of rear wheels can be driven separately, so that the pair of front wheels and the pair of rear wheels are in opposite directions as shown in FIGS. 6 (A) and 6 (B). When driven, it is possible to induce slippage due to idling of the wheels without accelerating the vehicle and to accelerate the yaw rotation of the vehicle. In the case of a four-wheel drive force distribution vehicle or a two-wheel drive force distribution vehicle, as shown in FIGS. 6 (C), (D), and (E), the vehicle is also driven by the drive for idling the wheels. A moment for rotating it around its center of gravity can be added, and it is possible to more accurately implement the yaw rotation of the vehicle accompanying the collision according to the present invention.

  FIG. 7 urges the yaw rotation of the own vehicle when it is determined that there is a possibility of collision of the own vehicle with another object, and a part of the impact energy in the collision direction caused by the collision with the other object Even if it is converted into yaw rotation energy of the own vehicle that does not synergize with energy to alleviate the total damage that the vehicle and particularly the occupant suffer, the vehicle is different from the other object due to the yaw rotation of the own vehicle increased by being promoted. Considering that there is a possibility of colliding with another object, the yaw rotation is promoted after confirming that there is no possibility that the vehicle will collide with another object. It is a flowchart which shows the control incorporating incorporating. In the flowchart of FIG. 7, the same step numbers as those in FIG. 3 are assigned to the same steps as those in the flowchart of FIG.

  In this embodiment, when the answer to step 50 is yes, the control proceeds to step 51, and when the step 60 is executed based on the calculation results of steps 10 to 40, the host vehicle Is checked for the possibility of a secondary collision that collides with another object, and it is then determined in step 52 whether there is a possibility of a secondary collision. In this case, the answer to step 52 is no, and if there is no possibility of a secondary collision even after executing step 60, the control proceeds to step 60 to reduce the coefficient of friction between the road surface and the tire of the host vehicle, Control for prompting the host vehicle to perform yaw rotation is performed, but if the answer to step 52 is yes, step 60 is bypassed. In other words, this is by converting a part of the impact energy in the collision direction into the yaw rotation of the own vehicle that does not synergize with this by prompting the yaw rotation of the own vehicle when there is a possibility of collision of the own vehicle with another object The control is executed to reduce the total damage to the vehicle and particularly to the occupant due to the collision, on condition that there is no possibility that the own vehicle will collide with another object by the urged yaw rotation.

  While the invention has been described in detail with reference to embodiments, it will be apparent to those skilled in the art that various modifications can be made to the embodiments within the scope of the invention.

  10 ... own car, 20 ... preceding car

Claims (1)

  A vehicle characterized in that the possibility of a collision of the own vehicle with another object is determined, and the yaw rotation of the own vehicle is urged when it is determined that the possibility exists.

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