Vehicle control device

Abstract

To provide a vehicle control device that can control a posture of a vehicle so that the vehicle can easily run over an obstacle existing ahead of the vehicle, without necessarily needing a special suspension mechanism.SOLUTION: A vehicle 10 senses an obstacle 50 existing ahead of the vehicle and controls a rear wheel-side distribution ratio Xr between front wheel driving torque Trf and rear wheel driving torque Trr. An electronic control device 90 makes the vehicle run over the obstacle 50 while increasing a ratio of the rear wheel driving torque Trr in the rear wheel-side distribution ratio Xr when the obstacle 50 which the vehicle can run over is sensed, compared to when the obstacle 50 is not sensed. The increasing of the ratio of the rear wheel driving torque Trr in the rear wheel-side distribution ratio Xr enables the vehicle 10 to incline rearward easily. This enables the vehicle 10 to easily run over the obstacle 50.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device that detects an obstacle ahead of the vehicle and controls the torque distribution between the drive torque of the front wheels and the drive torque of the rear wheels. [Background technology]

[0002] Vehicle control devices that control the attitude of the vehicle body, i.e., the attitude of the vehicle, are known. For example, one such device is described in Patent Document 1. In the vehicle control device described in Patent Document 1, the swing motion of a swing arm that can swing in the front-to-rear direction of the vehicle is controlled while the vehicle is traveling, thereby controlling the vehicle attitude. Furthermore, the swing motion of the swing arm is controlled, and the rotation speed and drive torque of each of the in-wheel motors for the front and rear wheels are controlled, thereby controlling the vehicle attitude. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-306733 Summary of the Invention [Problem to be solved by the invention]

[0004] The control device described in Patent Document 1 requires a special suspension mechanism called a swing arm to control the vehicle's posture, which may increase costs. Therefore, there is a need for a vehicle control device that can control the vehicle's posture to make it easier to overcome obstacles in front of the vehicle without necessarily requiring a special suspension mechanism.

[0005] The present invention has been made against the background of the above circumstances, and its purpose is to provide a vehicle control device that can control the vehicle's posture to make it easier to overcome obstacles in front of the vehicle, without necessarily requiring a special suspension mechanism. [Means for solving the problem]

[0006] The gist of the present invention is a vehicle control device that detects obstacles in front of the vehicle and controls the torque distribution between the drive torque of the front wheels and the drive torque of the rear wheels, and when a overcomeable obstacle is detected, the ratio of the drive torque of the rear wheels in the torque distribution is increased compared to when the obstacle is not detected, allowing the vehicle to overcome the obstacle. [Effects of the Invention]

[0007] According to the present invention, when a climbable obstacle is detected among the obstacles, the ratio of drive torque to the rear wheels in the torque distribution is increased compared to when the obstacle is not detected, and the obstacle is climbed over. By increasing the ratio of drive torque to the rear wheels in the torque distribution, the vehicle is more likely to assume a rearward tilting posture. This makes it easier for the vehicle to climb over the obstacle. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention; [Figure 2] 4 is an example of a flowchart illustrating a control operation of an electronic control device. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. [Example]

[0010] FIG. 1 is a schematic diagram of a vehicle 10 equipped with an electronic control device 90 according to an embodiment of the present invention.

[0011] The vehicle 10 is a well-known four-wheel drive vehicle equipped with front wheels 14 and rear wheels 16 that function as drive wheels. The vehicle 10 is capable of changing the ratio of rear wheel drive torque Trr to total torque, which is the sum of front wheel drive torque Trf [N·m] and rear wheel drive torque Trr [N·m], i.e., rear wheel side distribution rate Xr (=Trr / (Trf+Trr)). The front wheel drive torque Trf is the drive torque of the front wheels 14, and the rear wheel drive torque Trr is the drive torque of the rear wheels 16. "Drive torque" is the torque transmitted from a power source for traveling to each of the drive wheels, the front wheels 14 and the rear wheels 16. The "rear wheel side distribution rate Xr" corresponds to "torque distribution" in this invention. For example, if the vehicle 10 is equipped with a transfer (not shown) that transmits a portion of the output torque of the driving power source to the front wheels 14 and the remainder to the rear wheels 16, the change in the rear wheel distribution rate Xr is realized by adjusting the front wheel drive torque Trf transmitted to the front wheels 14. For example, if the vehicle 10 is equipped with two driving power sources that independently drive the front wheels 14 and the rear wheels 16, the change in the rear wheel distribution rate Xr is realized by adjusting the ratio between the output torques output from the two driving power sources.

[0012] For example, if the vehicle 10 is an electric vehicle or a hybrid electric vehicle equipped with an electric motor as a power source for driving, the drive battery 30 that supplies power to the electric motor is mounted in the lower part of the vehicle compartment. In this case, the electric motor has at least the electric motor function out of the electric motor function and the electric generator function.

[0013] The vehicle 10 is equipped with a forward detection device 24 capable of detecting an obstacle 50 in front of the vehicle 10 while traveling forward, and a rear detection device 26 capable of detecting an obstacle 50 behind the vehicle 10. For example, the forward detection device 24 and the rear detection device 26 are each well-known millimeter-wave radars. The obstacle 50 may be, for example, a rock falling onto the roadway 70, an object falling from another vehicle traveling in front of the vehicle 10, or the like.

[0014] The vehicle 10 is equipped with an electronic control device 90. The electronic control device 90 corresponds to the "control device" in the present invention. The electronic control device 90 is configured to include a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc., and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program stored in advance in the ROM while utilizing the temporary storage function of the RAM.

[0015] Various signals (e.g., vehicle speed V, distance D from the vehicle 10 to the obstacle 50, height H of the obstacle 50, etc.) based on detection values ​​from various sensors (e.g., vehicle speed sensor 80, front detection device 24, rear detection device 26, etc.) are input to the electronic control device 90. A control signal for controlling the rear wheel distribution rate Xr of the vehicle 10 is output from the electronic control device 90.

[0016] When the electronic control device 90 does not detect an obstacle 50, it controls the rear wheel distribution rate Xr to a predetermined distribution rate Xr1. The predetermined distribution rate Xr1 is a distribution rate determined in advance through experimentation or design, by which the power source of the vehicle 10 is operated to be advantageous in terms of energy efficiency (for example, fuel economy or electricity cost). When the rear wheel distribution rate Xr is controlled to the predetermined distribution rate Xr1, the drive wheels do not slip.

[0017] The electronic control unit 90 determines whether or not an obstacle 50 is detected ahead on the travel path 70 of the vehicle 10 while the vehicle 10 is traveling forward.

[0018] When the electronic control device 90 determines that an obstacle 50 has been detected ahead while the vehicle 10 is traveling forward, the electronic control device 90 determines whether the vehicle 10 is unavoidable from the obstacle 50. Whether the obstacle 50 is unavoidable is determined based on, for example, the distance D [m] between the vehicle 10 and the obstacle 50 and the vehicle speed V [km / h]. The shorter the distance D and the higher the vehicle speed V, the more likely it is that the obstacle 50 is determined to be unavoidable.

[0019] When the electronic control unit 90 determines that the vehicle 10 can avoid the obstacle 50, it again determines whether the obstacle 50 has been detected and whether the vehicle 10 cannot avoid the obstacle 50. For example, if the obstacle 50 has been avoided by the driver operating the steering wheel, when the electronic control unit 90 again determines whether the obstacle 50 has been detected and whether the vehicle 10 cannot avoid the obstacle 50, it determines that the obstacle 50 is not detected ahead of the vehicle 10 while the vehicle 10 is traveling forward. This is because the steering wheel operation has caused the detected position of the obstacle 50 ahead of the vehicle 10 to move to a position that does not obstruct the traveling of the vehicle 10.

[0020] When the electronic control device 90 determines that the vehicle 10 cannot avoid the obstacle 50, it determines whether the vehicle 10 can overcome the obstacle 50. Whether the vehicle 10 can overcome the obstacle 50 is determined based on, for example, the height H [m] of the obstacle 50 and the distance L [m] between the roadway 70 and the underside of the body of the vehicle 10. The distance L is determined in advance based on the specifications of the vehicle 10. For example, if the difference (= HL) between the height H and the distance L is greater than a predetermined length d [m], it is determined that the vehicle 10 can overcome the obstacle 50. The predetermined length d is a length that is determined in advance experimentally or by design as being capable of the vehicle 10 overcoming the obstacle 50.

[0021] When the electronic control device 90 determines that the vehicle 10 can overcome the obstacle 50, it changes the rear wheel allocation rate Xr from a predetermined allocation rate Xr1 to an allocation rate Xr2 (>Xr1). The allocation rate Xr2 is an allocation rate that increases the proportion of the rear wheel drive torque Trr compared to the predetermined allocation rate Xr1. For example, the front wheel drive torque Trf is decreased and the rear wheel drive torque Trr is increased. This allows the vehicle 10 to overcome the obstacle 50 in a controlled manner that makes it more likely to lean backward. When the electronic control device 90 determines that the vehicle 10 cannot overcome the obstacle 50, it activates, for example, a well-known automatic brake installed in the vehicle 10 to stop the vehicle 10.

[0022] After changing the rear wheel allocation rate Xr to the allocation rate Xr2, the electronic control device 90 determines whether or not an obstacle 50 is detected behind the vehicle 10 on the road 70 within a predetermined period T. The predetermined period T is, for example, a predetermined period from the time when the obstacle 50 is no longer detected ahead of the vehicle 10 until the vehicle 10 passes the obstacle 50 and the obstacle 50 is assumed to be detected behind the vehicle 10. The predetermined period T is determined according to the vehicle speed V.

[0023] If the electronic control device 90 determines that an obstacle 50 is detected behind the vehicle 10 within the predetermined period T, it determines that the vehicle 10 has passed the obstacle 50. If the electronic control device 90 determines that an obstacle 50 is not detected behind the vehicle 10 within the predetermined period T, it determines that the vehicle 10 has not passed the obstacle 50 safely.

[0024] After determining that the vehicle 10 has passed the obstacle 50, the electronic control unit 90 controls the rear wheel allocation rate Xr to return to the predetermined allocation rate Xr1. After controlling the rear wheel allocation rate Xr to return to the predetermined allocation rate Xr1, the electronic control unit 90 determines whether there is an abnormality in the vehicle system. The vehicle system is the entire device required for the vehicle 10 to run normally.

[0025] The electronic control device 90 controls the vehicle 10 to stop when it determines that the vehicle 10 has passed the obstacle 50 and that there is an abnormality in the vehicle system, and when it determines that the vehicle 10 has not passed the obstacle 50 safely.

[0026] When the electronic control unit 90 determines that the vehicle 10 has passed the obstacle 50 and that there is no abnormality in the vehicle system, it executes control to maintain the running state of the vehicle 10 as it is.

[0027] Fig. 2 is an example of a flowchart illustrating the control operation of the electronic control unit 90. The flowchart in Fig. 2 is repeatedly started while the vehicle is running.

[0028] First, in step (hereinafter, step will be omitted) S10, the rear wheel allocation rate Xr is controlled to a predetermined allocation rate Xr1. After S10 is executed, in S20, it is determined whether or not an obstacle 50 has been detected ahead of the vehicle 10. If the determination in S20 is YES, in S30, it is determined whether or not the vehicle 10 is unable to avoid the obstacle 50.

[0029] If the determination in S30 is YES, then in S40 it is determined whether the vehicle 10 can overcome the obstacle 50. If the determination in S40 is NO, then in S50 the automatic brake is activated to stop the vehicle 10. After execution of S50, the process ends. If the determination in S40 is YES, then in S60 the front wheel drive torque Trf is decreased and the rear wheel drive torque Trr is increased. After execution of S60, then in S70 it is determined whether an obstacle 50 has been detected behind the vehicle 10 within a predetermined period T.

[0030] If the determination in S70 is YES, then in S80 it is determined that the vehicle 10 has passed the obstacle 50, and the rear wheel allocation rate Xr is controlled to a predetermined allocation rate Xr1. After S80 is executed, in S90 it is determined whether or not there is an abnormality in the vehicle system. If the determination in S70 is NO, then in S100 it is determined that the vehicle 10 has not safely passed the obstacle 50. In both cases where the determination in S90 is NO or after S100 is executed, a command to stop the vehicle 10 is issued in S110, i.e., the automatic brake is activated. After S110 is executed, the process ends. In all cases where the determination in S20 is NO, where the determination in S30 is NO, and where the determination in S90 is YES, the process returns.

[0031] According to this embodiment, when a climbable obstacle 50 is detected ahead of the vehicle 10, the ratio of the rear wheel drive torque Trr in the rear wheel side allocation rate Xr is increased and the vehicle 10 is allowed to climb over the obstacle 50, compared to when the obstacle 50 is not detected. Increasing the ratio of the rear wheel drive torque Trr in the rear wheel side allocation rate Xr makes the vehicle 10 more likely to assume a rearward tilting posture. This makes it easier for the vehicle 10 to climb over the obstacle 50. For example, if the drive battery 30 is mounted below the passenger compartment, the vehicle 10 will be able to climb over the obstacle 50 more easily, reducing damage to the underside of the vehicle body, and reducing damage to the drive battery 30 caused by the obstacle 50.

[0032] The above-described embodiments of the present invention are merely illustrative, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0033] In the above-described embodiment, the vehicle 10 is equipped with the forward detection device 24 and the rearward detection device 26, but the present invention is also applicable to a vehicle that is equipped with the forward detection device 24 but not the rearward detection device 26, for example.

[0034] In the above-described embodiment, when the determination in S40 in the flowchart of FIG. 2 is NO, the automatic brake is activated and the vehicle 10 is stopped. However, when the determination in S20 in the flowchart of FIG. 2 is YES, the automatic brake may be activated so that the vehicle 10 can easily avoid the obstacle 50.

[0035] In the above embodiment, the vehicle 10 is a full-time four-wheel drive vehicle, but the present invention is also applicable to part-time four-wheel drive vehicles.

[0036] In the above-described embodiment, a swing arm for controlling the posture of the vehicle 10 is not provided, but a swing arm may also be provided. In such a case, the swing operation of the swing arm is controlled while the proportion of the rear wheel drive torque Trr in the rear wheel distribution rate Xr is increased, so that the vehicle 10 is more likely to assume a rearward tilt posture and to overcome the obstacle 50 more easily.

[0037] In the above-described embodiment, the vehicle 10 is equipped with an electric motor as a power source for traveling, but the present invention is also applicable to vehicles that do not have an electric motor. If the vehicle does not have an electric motor, the drive battery 30 is not mounted under the passenger compartment, but even in such a case, the vehicle can easily overcome the obstacle 50, and damage to the underside of the vehicle body is reduced. [Explanation of symbols]

[0038] 10: Vehicle, 14: Front wheel, 16: Rear wheel, 50: Obstacle, 90: Electronic control unit (control unit), Trf: Front wheel drive torque (Front wheel drive torque), Trr: Rear wheel drive torque (Rear wheel drive torque), Xr: Rear wheel side distribution rate (torque distribution)

Claims

[Claim 1] A vehicle control device that detects an obstacle ahead of a vehicle and controls torque distribution between a front wheel drive torque and a rear wheel drive torque, When a climbable obstacle is detected among the obstacles, the ratio of the driving torque of the rear wheels in the torque distribution is increased compared to when the obstacle is not detected, and the vehicle climbs over the obstacle. A vehicle control device characterized by:

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