JP6438328B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device capable of distributing driving force to front wheels and rear wheels.

  Conventionally, when a vehicle tries to get over a step, a technique has been proposed that makes it easy to get over the step by increasing the driving force with respect to the amount of depression of the accelerator, that is, improve the overpass performance (for example, Patent Document 1).

JP 2012-2222859 A

  By the way, in a vehicle in which the driving force can be distributed to the front wheels and the rear wheels, when the vehicle tries to get over the step, the difference between the driving force of one of the front wheels and the rear wheel that is in contact with the step. The ratio of the other driving force of the front wheels and the rear wheels that are not in contact with each other contributes to the passing drive force for getting over the step.

  Therefore, in a vehicle in which driving force can be distributed to the front wheels and rear wheels, when the above technique is applied and the vehicle tries to get over the step, simply increasing the driving force provides sufficient riding performance. There was a problem that I couldn't.

  Therefore, an object of the present invention is to provide a vehicle control device capable of improving the step-over performance of a step.

  In order to solve the above-described problems, a vehicle control device according to the present invention is a vehicle control device for a vehicle that can distribute a driving force from a driving source to front wheels and rear wheels, at a step in the traveling direction of the vehicle. A step contact determination unit that determines whether the front wheel or the rear wheel has contacted, and a step contact determination unit that determines that the front wheel or the rear wheel has contacted the step. A driving force distribution control unit that distributes the driving force unevenly to the abutting front wheel or rear wheel.

  The driving force distribution control unit may distribute the driving force to the front wheel or the rear wheel that is in contact with the step so that the maximum distribution ratio can be distributed.

  The driving force distribution control unit may distribute the driving force to the front wheels or the rear wheels that are in contact with the step when the maximum driving force that can be output from the driving source is equal to or greater than a predetermined threshold.

  In addition, a slip detection unit that detects a slip of a front wheel or a rear wheel that is in contact with the step is provided, and the driving force distribution control unit is configured to detect the front wheel and the rear wheel when slip is detected by the slip detection unit. The driving force may be distributed to the wheel so as to reduce the driving force with respect to the front wheel or the rear wheel that is in contact with the step.

  Further, when the front wheel or the rear wheel passes over the step, the driving force may be distributed to the front wheel and the rear wheel with a preset initial distribution.

  According to the present invention, it is possible to improve the step-over performance.

It is a figure which shows the structure of a vehicle. It is the functional block diagram which showed the schematic function of the vehicle control apparatus. It is explanatory drawing for demonstrating a color image and a distance image. It is a figure for demonstrating an example of a vehicle control process. It is explanatory drawing for demonstrating a boarding drive force. It is a figure explaining the overpass driving force for getting over the level difference by the front wheel and the rear wheel when going over the level difference by reverse travel. It is a flowchart which shows the flow of a vehicle control process. It is a flowchart which shows the flow of a driving force distribution process.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is a diagram illustrating a configuration of the vehicle 100. As shown in FIG. 1, the vehicle 100 is a so-called hybrid vehicle having an engine 102, a motor 104, and a generator 106. Here, a hybrid vehicle will be described as an example of the vehicle 100, but an electric vehicle or a motor-free vehicle may be applied as the vehicle 100.

  The engine 102 is a gasoline engine or a diesel engine, and based on the control of the ECU 108 (engine control unit), a driving force is obtained by burning fuel supplied from a fuel tank (not shown), and the obtained driving force is obtained. Is output to the damper 124.

  The motor 104 is connected to the battery 112 via the inverter 110, receives electric power from the battery 112, and transmits driving force to the rotating shaft 114. Further, the motor 104 functions as a generator that generates power by regeneration by applying a braking force to the vehicle 100 instead of the brake 118 or together with the brake 118 when the vehicle 100 is decelerated.

  The generator 106 is connected to the battery 112 via the inverter 110, and causes the battery 112 to store electric power generated by receiving driving force from the engine 102 via a power split mechanism 126 described later. Further, the generator 106 may supply the generated power to the motor 104. Furthermore, the generator 106 also functions as an electric motor (motor) at a timing different from that of power generation, and is driven by electric power supplied from the battery 112 via the inverter 110.

  As the power split mechanism 126, for example, a planetary gear mechanism including a sun gear, a ring gear, a planetary gear, and a carrier is applied. The sun gear is connected to the rotating shaft of the generator 106, the ring gear is connected to the rotating shaft 114, and the carrier is connected to the engine 102 via the damper 124. In the power split mechanism 126, for example, the driving force transmitted from the engine 102 via the damper 124 is split and transmitted to the generator 106 and the rotating shaft 114. The rotating shaft 114 and the drive shaft 132 are provided with gear mechanisms 128 a and 128 b, respectively, and the gear mechanisms 128 a and 128 b transmit driving force from the rotating shaft 114 to the drive shaft 132.

  The driving force obtained by the engine 102 and the motor 104 is transmitted to the front wheel 120 as a driving force via the rotating shaft 114, the gear mechanisms 128a and 128b, the drive shaft 132, the front differential gear 130, and the front wheel shaft 116. Further, the power obtained by the engine 102 and the motor 104 is transmitted to the rear wheel via the rotating shaft 114, the gear mechanisms 128a and 128b, the drive shaft 132, the electronic control coupling 134, the rear differential gear 136, and the rear wheel shaft 138. 122 is also transmitted as a driving force.

  In the connected state, the electronic control coupling 134 transmits the driving force output from the engine 102 and the motor 104 to the rear wheel 122 via the rear differential gear 136 and the rear wheel shaft 138. Further, the electronic control coupling 134 transmits the driving force output from the engine 102 and the motor 104 only to the front wheels 120 in the disconnected state.

  In the electronic control coupling 134, the initial distribution is set so that the ratio of the driving force transmitted to the front wheels 120 and the driving force transmitted to the rear wheels 122 is 70%: 30%. The electronic control coupling 134 has a ratio of the driving force transmitted to the front wheels 120 and the driving force transmitted to the rear wheels 122 in accordance with the running state and vehicle control processing to be described in detail later, 100%: Adjustment is possible in the range of 0% to 50%: 50%. That is, when the maximum possible driving force is distributed to the front wheels 120, the ratio between the driving force transmitted to the front wheels 120 and the driving force transmitted to the rear wheels 122 is 100%: 0%. When the maximum possible driving force is distributed to the rear wheel 122, the ratio between the driving force transmitted to the front wheel 120 and the driving force transmitted to the rear wheel 122 is 50%: 50%. Become.

  Thus, the vehicle 100 is an AWD (All Wheel Drive) vehicle that is driven only by the front wheels 120 or by the front wheels 120 and the rear wheels 122. Here, an explanation will be given by taking as an example an AWD vehicle that is driven only by the front wheels 120 or by the front wheels 120 and the rear wheels 122, but it is applicable to an AWD vehicle that can distribute the driving force to the front wheels 120 and the rear wheels 122. Can do.

  The vehicle control device 140 is configured by a semiconductor integrated circuit including a central processing unit (CPU), a ROM storing a program, a RAM as a work area, and the like, and comprehensively controls each part of the vehicle 100.

  The vehicle control device 140 is connected to the shift position sensor 150, the accelerator pedal sensor 152, the brake pedal sensor 154, the vehicle speed sensor 156, the acceleration sensor 158, and the rotation speed sensors 160 and 162, and signals indicating values detected by the sensors. Is entered.

  The vehicle control device 140 is connected to the ECU 108 and the inverter 110, and controls driving or power generation of the engine 102, the motor 104, and the generator 106 via the ECU 108 and the inverter 110 based on signals input from the sensors. . ECU 108 detects the engine speed of engine 102 and outputs a signal indicating the engine speed to vehicle control device 140.

  Further, the vehicle control device 140 is connected to the electronic control coupling 134, and controls the coupling state and the disconnection state of the electronic control coupling 134, so that the driving force from the engine 102 and the motor 104 is supplied to the front wheel 120 and the rear wheel. 122.

  Shift position sensor 150 detects a shift position (forward “D”, reverse “R”, parking “P”, neutral “N”, etc.), and outputs a signal indicating the shift position to vehicle control device 140. The accelerator pedal sensor 152 detects an accelerator pedal depression amount (accelerator depression amount) and outputs a signal indicating the accelerator depression amount to the vehicle control device 140. The brake pedal sensor 154 detects the depression amount (brake depression amount) of the brake pedal, and outputs a signal indicating the brake depression amount to the vehicle control device 140.

  The vehicle speed sensor 156 detects the vehicle speed of the vehicle 100 and outputs a signal indicating the vehicle speed to the vehicle control device 140. The acceleration sensor 158 detects the acceleration of the vehicle 100 and outputs a signal indicating the acceleration to the vehicle control device 140. The rotation speed sensors 160 and 162 are, for example, resolvers, detect the rotation speeds of the motor 104 and the generator 106, and output a signal indicating the rotation speed to the vehicle control device 140.

  In addition, the vehicle control device 140 is connected to the imaging devices 164 and 166. In the vehicle 100, the two imaging devices 164 are arranged in a substantially horizontal direction so that the optical axes of the two imaging devices 164 are substantially parallel on the front side of the vehicle 100, and the two imaging devices 166 are arranged on the rear side of the vehicle 100. They are spaced apart in a substantially horizontal direction so that their optical axes are substantially parallel. The imaging devices 164 and 166 are configured to include an imaging element such as a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS).

  And the imaging device 164 images the environment equivalent to the front of the vehicle 100, and produces | generates the color image by a color value. The imaging device 166 captures an environment corresponding to the rear of the vehicle 100 and generates a color image based on color values. Here, the color value is from a YUV format color space consisting of one luminance (Y) and two color differences (U, V), and three hues (R (red), G (green), B (blue)). A numerical value group represented by any one of the RGB color space or the HSB color space consisting of hue (H), saturation (S), and brightness (B).

  FIG. 2 is a functional block diagram showing a schematic function of the vehicle control device 140. As shown in FIG. 2, when the vehicle control device 140 performs the vehicle control process, the step detection unit 170, the step contact determination unit 172, the permission determination unit 174, the driving force distribution control unit 176, the drive control unit 178, the slip It functions as a detection unit 180 and an overpass completion determination unit 182. Further, the level difference detection unit 170 functions as an image processing unit 170a, a three-dimensional position information generation unit 170b, and a three-dimensional object specifying unit 170c.

  The level difference detection unit 170 acquires image data from each of the imaging devices 164 and 166, and detects a level difference in the traveling direction (front and rear) of the vehicle 100 based on the acquired image data. Below, the process which detects a specific level | step difference is demonstrated. Here, a step detection process for detecting a step in front of the vehicle 100 based on the image data acquired from the imaging device 164 will be described. However, based on the image data acquired from the imaging device 166, the rear of the vehicle 100 is described. The step detection process for detecting the step is performed in the same manner.

(Step detection processing)
The image processing unit 170a acquires image data from each of the two imaging devices 164, and selects a block corresponding to a block arbitrarily extracted from one image data (for example, an array of horizontal 4 pixels × vertical 4 pixels) as the other image data. The parallax is derived using so-called pattern matching that is searched from the above. Here, “horizontal” indicates the horizontal direction of the captured color image, and “vertical” indicates the vertical direction of the captured color image.

  As this pattern matching, it is conceivable to compare the luminance (Y color difference signal) in units of blocks indicating an arbitrary image position between two pieces of image data. For example, SAD (Sum of Absolute Difference) that takes a luminance difference, SSD (Sum of Squared Intensity Difference) that uses the difference squared, or NCC that takes the similarity of a variance value obtained by subtracting an average value from the luminance of each pixel There are methods such as (Normalized Cross Correlation). The image processing unit 170a performs such block-unit parallax derivation processing for all blocks displayed in the detection area (for example, horizontal 600 pixels × vertical 180 pixels). Here, the block is assumed to be horizontal 4 pixels × vertical 4 pixels, but the number of pixels in the block can be arbitrarily set.

  However, the image processing unit 170a can derive the parallax for each block, which is a unit of detection resolution, but cannot recognize what kind of three-dimensional object the block is. Therefore, the parallax information is independently derived not in units of solid objects but in units of detection resolution (for example, blocks) in the detection region. Here, an image in which the parallax information derived in this way (corresponding to a relative distance described later) is associated with image data is referred to as a distance image.

  FIG. 3 is an explanatory diagram for explaining the color image 200 and the distance image 202. For example, it is assumed that a color image 200 as shown in FIG. 3A is generated for the detection region 204 through the two imaging devices 164. However, only one of the two color images 200 is schematically shown here for easy understanding. In the present embodiment, the image processing unit 170a obtains the parallax for each block from the color image 200, and forms the distance image 202 as shown in FIG. Each block in the distance image 202 is associated with the parallax of the block. Here, for convenience of description, blocks from which parallax is derived are represented by black dots.

  Returning to FIG. 2, the three-dimensional position information generation unit 170 b uses the so-called stereo method to calculate disparity information for each block in the detection region 204 based on the distance image 202 generated by the image processing unit 170 a. Convert into 3D position information including horizontal distance, height and relative distance. Here, the stereo method is a method of deriving the relative distance of the three-dimensional object from the imaging device 164 from the parallax of the three-dimensional object by using a triangulation method. At this time, the three-dimensional position information generation unit 170b determines the target based on the relative distance of the target part and the detected distance on the distance image 202 between the point on the road surface at the same relative distance as the target part and the target part. The height of the part from the road surface is derived. Since various known techniques can be applied to the relative distance deriving process and the three-dimensional position specifying process, description thereof is omitted here.

  The three-dimensional object specifying unit 170c has an arbitrary target part as a base point, the target part, the difference in horizontal distance, and the difference in height (may include a difference in relative distance) within a predetermined range. Group target parts that are considered to correspond to a three-dimensional object. Here, the predetermined range is represented by a distance in the real space, and can be set to an arbitrary value (for example, 1.0 m). In addition, the three-dimensional object specifying unit 170c also applies to the target part newly added as a result of grouping, with the three-dimensional object being equal, with the difference in horizontal distance and the difference in height being within a predetermined range from the target part. Group parts. As a result, if the distance between the target parts is within a predetermined range, all the target parts are grouped.

  Then, the three-dimensional object specifying unit 170c uses the three-dimensional position information derived by the three-dimensional position information generating unit 170b to specify which three-dimensional object the grouped target portion corresponds to.

  Thus, the vehicle control device 140 executes cruise control for keeping the distance between the preceding vehicle and the preceding vehicle at a safe distance according to the specified three-dimensional object, speed control processing based on the speed limit indicated on the road sign, and the like.

  In the present embodiment, the three-dimensional object specifying unit 170c specifies, as a three-dimensional object, a step whose height is not more than a predetermined value (for example, 20 cm) and the vehicle 100 can get over. In addition, the three-dimensional object specifying unit 170c derives the distance from the front wheel 120 and the rear wheel 122 of the vehicle 100 to the step based on the relative distance to the target portion specified as the step.

  The step contact determination unit 172 determines whether the front wheel 120 or the rear wheel 122 is in contact with the step detected by the step detection unit 170. Specifically, the step contact determination unit 172 has the same or a distance of movement in the direction approaching the step of the vehicle 100 with respect to the distance to the step detected by the step detection unit 170. When it is within the range, it is determined that the front wheel 120 or the rear wheel 122 is in contact with the step. The moving distance in the direction approaching the step of the vehicle 100 is derived from, for example, the rotational speed of the front wheels 120 and the rear wheels 122, the rotational speed of the motor 104, ODO (ODOmeter), and the like.

  Further, when the step contact determination unit 172 determines that the front wheel 120 or the rear wheel 122 is in contact with the step, the wheel contacted with the step, that is, the front wheel 120 contacted with the step, or It is also determined whether the rear wheel 122 is in contact with the step.

  The permission determination unit 174 derives the total driving force that can be output with respect to the moving direction of the vehicle 100 to the level difference, based on the temperature of the motor 104, the remaining amount of the battery 112, the remaining fuel amount of the engine 102, and the like. Then, when the derived total driving force is equal to or greater than a driving force threshold (for example, 50% of the maximum driving force) based on the maximum driving force that the motor 104 and the engine 102 can originally output, the permission determination unit 174 A permission determination is made to allow oversteps. On the other hand, when the derived total driving force is less than the driving force threshold, the permission determining unit 174 performs a non-permission determination that the step cannot be overtaken.

  When the permission determination unit 174 determines that the step can be overridden by the permission determination unit 174, the driving force distribution control unit 176 moves in the direction of overcoming the step based on the signal indicating the accelerator depression amount output from the accelerator pedal sensor 152. It is determined whether the driver is willing to advance the vehicle 100. That is, here, after the front wheel 120 or the rear wheel 122 abuts on the step, it is further determined whether or not the accelerator is depressed to get over the step depending on whether the accelerator depression amount is a predetermined value or more.

  When the driving force distribution control unit 176 determines that the driver intends to get over the step, the driving force distribution control unit 176 gives the maximum possible distribution ratio to the front wheels 120 or the rear wheels 122 that are in contact with the step. The driving force is distributed unevenly so that For example, when the front wheel 120 is in contact with the step, the electronic control coupling 134 is cut and the driving force is distributed in an uneven manner so that the driving force is transmitted only to the front wheel 120. When the rear wheel 122 is in contact with the step, the electronic control coupling 134 is connected, and the ratio of the driving force transmitted to the front wheel 120 to the driving force transmitted to the rear wheel 122 is 50. %: The driving force is unevenly distributed so as to be 50%.

  The slip detection unit 180 detects the slip of the front wheel 120 or the rear wheel 122 that is in contact with the step while the driving force distribution control unit 176 distributes the driving force in an uneven distribution. As a slip detection method, for example, it is determined that the vehicle is slipping when the rotational speed difference between the front wheel 120 and the rear wheel 122 is equal to or greater than a predetermined rotational speed difference, or the front wheel 120 or the rear wheel 122 that is in contact with the step. And a method of determining slip based on the vehicle speed is applied.

  When the slip detection unit 180 determines that the front wheel 120 or the rear wheel 122 that is in contact with the step is slipping, the driving force distribution control unit 176 is in contact with the front wheel 120 or the rear wheel 122 that is in contact with the step. The driving force is redistributed so as to reduce the driving force transmitted to. For example, when the front wheel 120 is in contact with a step, the distribution of weight distribution is performed so that the ratio of the driving force transmitted to the front wheel 120 and the driving force transmitted to the rear wheel 122 is 100%: 0%. If a slip is detected, the driving force is redistributed so that the ratio of the driving force transmitted to the front wheel 120 and the driving force transmitted to the rear wheel 122 is 90%: 10%. To do.

  As described above, the driving force distribution control unit 176 determines whether the front wheel 120 or the rear wheel 122 in contact with the step is slipped every time the slip detection unit 180 determines that the front wheel 120 or the rear wheel 122 is slipping. The driving force is redistributed so as to reduce the driving force transmitted to the rear wheel 122. However, when the ratio of the driving force transmitted to the front wheels 120 and the driving force transmitted to the rear wheels 122 reaches 70%: 30%, which is set as the initial distribution, the driving force distribution control unit 176 thereafter Even if a slip is detected, the driving force is not redistributed.

  Whether the overpass completion is completed by determining whether the vehicle 100 has moved a certain distance that is assumed to have passed the step after the front wheel 120 or the rear wheel 122 abuts the step. Determine.

  Then, the driving force distribution control unit 176 determines the driving force transmitted to the front wheel 120 and the rear if the front wheel 120 or the rear wheel 122 that is in contact with the step has passed the step. The driving force is distributed such that the ratio of the driving force transmitted to the wheel 122 is 70%: 30% set as the initial distribution.

  FIG. 4 is a diagram for explaining an example of the vehicle control process. Here, the case of overcoming a step by reverse travel will be described.

  As shown in FIG. 4A, it is assumed that there is a step B on which the vehicle 100 can ride over the rear of the vehicle 100 and the vehicle 100 moves backward so as to approach the step B. Then, when the level difference B is detected by the level difference detection unit 170 and the rear wheel 122 of the vehicle 100 comes into contact with the level difference B as shown in FIG. 4B, the level difference contact determination unit 172 It is determined that 122 is in contact.

  Thereafter, the permission determination unit 174 derives the total driving force that can be output by the backward movement of the vehicle 100, and performs permission determination that the step B can be overridden if the derived total driving force is equal to or greater than the driving force threshold. . When the driving force distribution control unit 176 determines that the driver is willing to move the vehicle 100 backward, the driving force distribution control unit 176 sets the electronic control coupling 134 in a connected state and transmits the driving force transmitted to the front wheels 120 and the rear wheels 122. The distribution of the driving force is distributed so that the ratio to the driving force is 50%: 50%.

  Thereafter, as shown in FIG. 4C, when the rear wheel 122 passes over the step B, the overpass completion determination unit 182 determines that the overstep of the step has been completed, and the driving force distribution control unit 176 applies to the front wheel 120. The driving force is distributed so that the ratio between the transmitted driving force and the driving force transmitted to the rear wheel 122 is the initial distribution.

  Then, as shown in FIG. 4D, when the vehicle 100 further moves backward and the front wheel 120 contacts the step B, the step contact determination unit 172 determines that the front wheel 120 contacts the step B. . Thereafter, the permission determination unit 174 derives the total driving force that can be output by the backward movement of the vehicle 100, and performs permission determination that the step B can be overridden if the derived total driving force is equal to or greater than the driving force threshold.

  When the driving force distribution control unit 176 determines that the driver intends to move the vehicle 100 backward, the driving force distribution control unit 176 sets the electronic control coupling 134 in a disconnected state, and transmits the driving force transmitted to the front wheels 120 and the rear wheels 122. The distribution of the driving force is distributed so that the ratio is 100%: 0%.

  Thereafter, as shown in FIG. 4 (e), when the front wheel 120 passes over the step B, the overtaking completion determination unit 182 determines that the overtaking of the step B has been completed, and the driving force distribution control unit 176 applies to the front wheel 120. The driving force is distributed so that the ratio between the transmitted driving force and the driving force transmitted to the rear wheel 122 is the initial distribution.

  As shown in FIG. 4B, after the distribution of the driving force is distributed with the rear wheel 122 in contact with the step B, the rear wheel 122 is moved to the step B as shown in FIG. The slip detection unit 180 detects the slip of the rear wheel 122 until the vehicle is overtaken. Also, as shown in FIG. 4D, after the front wheel 120 is in contact with the step B, the driving force is distributed unevenly, and then the front wheel 120 gets over the step B as shown in FIG. Until then, the slip detection unit 180 detects the slip of the front wheel 120.

  FIG. 5 is an explanatory diagram for explaining the overpass driving force. In FIG. 5, the front wheel 120 or the rear wheel 122 when contacting the step B is indicated by a solid line, and the front wheel 120 or the rear wheel 122 when riding on the step B is indicated by a broken line.

  Here, as indicated by cross hatching in FIG. 5, the axial weight Ft to which a part of the weight of the vehicle 100 is distributed acts on the front wheel 120 or the rear wheel 122 downward in the vertical direction. Of the axial load Ft, the tangential force component Fta (indicated by a solid arrow in FIG. 4) at the contact point A with the step B on the front wheel 120 or the rear wheel 122 is Ft · sin α.

…（数式１）
ここで、長さｂは、前輪１２０または後輪１２２の半径ｃから段差Ｂの高さＨを減算した値となり、長さａは、パスカルの定理から長さｂ、半径ｃで求められる。すなわち、角αおよび力の成分Ｆｔａは、検出された段差Ｂの高さＨ、および、既知の前輪１２０または後輪１２２の半径ｃから導出される。 This angle α is derived from the cosine theorem by the following formula 1.

... (Formula 1)
Here, the length b is a value obtained by subtracting the height H of the step B from the radius c of the front wheel 120 or the rear wheel 122, and the length a is obtained by the length b and the radius c from Pascal's theorem. That is, the angle α and the force component Fta are derived from the detected height H of the step B and the known radius c of the front wheel 120 or the rear wheel 122.

…（数式２） Further, the following Expression 2 is derived from the relational expression of cos α = b / c and b = c−H. Even using Equation 2, the angle α and the force component Fta are derived from the detected height H of the step B and the known radius c of the front wheel 120 or the rear wheel 122.

... (Formula 2)

  This force component Fta becomes a resistance when overcoming the step B. The angle α gradually decreases as the front wheel 120 or the rear wheel 122 rides on the step B, and the force component Fta continuously decreases as the angle α changes.

  Further, assuming that the running resistance (for example, rolling resistance not affected by the vehicle speed) acting on the entire vehicle 100 at the vehicle speed is the running resistance R, Ft · sin α and R are the sum of the resistances. If the vehicle 100 can output at least a driving force equal to the total driving force Ft · sin α + R that is the sum of Ft · sin α and R, the vehicle 100 can pass over the step B.

  FIG. 6 is a diagram for explaining the overpass driving force for overcoming the step B by the front wheel 120 and the rear wheel 122 when overcoming the step B by reverse travel. As shown in FIG. 6, when the rear wheel 122 is in contact with the step B, the driving force Fr transmitted to the rear wheel 122 that is in contact with the step B is the overpass driving force Fr for getting over the step B as it is. Acting on the step B. On the other hand, the driving force Ff transmitted to the front wheel 120 not in contact with the step B acts on the step B as an overpass driving force Ffcosα that is a product of cosα.

  In the vehicle 100, when the sum of the overpass driving force Fr and the overpass driving force Ffcosα is equal to or greater than the overpassable driving force Ft · sinα + R, the rear wheel 122 can pass over the step B. Accordingly, when the load distribution is unevenly distributed to the rear wheel 122 that is in contact with the step B, the step B is generally reduced with less driving force than when the load is not distributed to the rear wheel 122 that is in contact with the step B. It is possible to get over.

  As described above, in the vehicle 100 in which the driving force can be distributed to the front wheel 120 and the rear wheel 122, when the front wheel 120 or the rear wheel 122 contacts the step B, the front wheel 120 or the rear wheel that contacts the step B. The maximum unbalance distribution is performed in 122 as much as possible. As a result, when the step B is carried over, the driving force output from the engine 102 and the motor 104 can be reduced, and the overpass performance can be improved. In particular, in a hybrid vehicle in which the reverse drive is performed only by the motor 104, the power of the engine 102 cannot be added when overcoming the step B by updating, which is particularly useful.

  Next, the flow of the vehicle control process for performing the above-described constant speed traveling process will be described in detail using a flowchart.

  FIG. 7 is a flowchart showing the flow of the vehicle control process. As shown in FIG. 7, when the vehicle control process is executed, the level difference detection unit 170 detects the level difference B (S300). Then, the step contact determination unit 172 detects whether or not the step B is detected in S300, and determines whether the front wheel 120 or the rear wheel 122 is in contact with the detected step B (S302).

  If the front wheel 120 or the rear wheel 122 is not in contact with the step B (NO in S302), the vehicle control process is terminated. On the other hand, when the front wheel 120 or the rear wheel 122 contacts the step B (YES in S302), the permission determination unit 174 derives the total driving force that can be output by the vehicle 100 moving forward or backward (S304).

  Subsequently, the permission determination unit 174 determines whether the total driving force derived in S304 is equal to or greater than the driving force threshold, that is, whether the step B can be overridden (S306). And when the total driving force derived | led-out by S304 is less than a driving force threshold value and the nonpermission determination which cannot pass over a level | step difference is impossible (NO in S306), the said vehicle control process is complete | finished.

  On the other hand, when the total driving force derived in S304 is equal to or greater than the driving force threshold value and permission determination is made that the step B can be overridden (YES in S306), the driving force distribution control unit 176 is output from the shift position sensor 150. It is determined whether the signal indicating the shift position is forward (S308).

  When the signal indicating the shift position output from the shift position sensor 150 is forward (YES in S308), the driving force distribution control unit 176 performs driving force distribution processing for overcoming the step B by moving forward (S310). The driving force distribution process will be described later in detail.

  On the other hand, when the signal indicating the shift position output from the shift position sensor 150 is not forward (NO in S308), the driving force distribution control unit 176 indicates that the signal indicating the shift position output from the shift position sensor 150 is backward. Is determined (S312).

  When the signal indicating the shift position output from the shift position sensor 150 is reverse (YES in S312), the driving force distribution control unit 176 performs driving force distribution processing for overcoming the step B by reverse driving (S310).

  After the execution of the driving force distribution process (S310), the passover completion determination unit 182 determines whether the front wheel 120 or the rear wheel 122 in contact with the step B has completed the step B overpass (S314). Then, when the front wheel 120 or the rear wheel 122 that is in contact with the step B has not completed the overtaking of the step B (NO in S314), the slip detection unit 180 is configured to contact the front wheel 120 or the rear wheel that is in contact with the step B. It is determined whether or not 122 slip has been detected (S316). When the slip of the front wheel 120 or the rear wheel 122 in contact with the step B is not detected (NO in S316), the process returns to S314.

  On the other hand, when the slip of the front wheel 120 or the rear wheel 122 that is in contact with the step B is detected (YES in S316), the driving force distribution control unit 176 applies to the front wheel 120 or the rear wheel 122 that is in contact with the step B. The driving force is redistributed so as to reduce the driving force (S318). Subsequently, the driving force distribution control unit 176 determines whether or not the distribution of the driving force to the front wheels 120 and the rear wheels 122 is the initial distribution (S320). If the distribution is the initial distribution (YES in S320), the vehicle control is performed. The process ends, and if it is not the initial distribution (NO in S320), the process returns to S314.

  Further, when the front wheel 120 or the rear wheel 122 that is in contact with the step B completes the ride over the step B (YES in S314), the driving force distribution control unit 176 transmits the driving force transmitted to the front wheel 120 and the rear wheel 122. The driving force is distributed so that the ratio with the driving force transmitted to the initial distribution becomes the initial distribution (S322), and the vehicle control process ends. Further, when the signal indicating the shift position output from the shift position sensor 150 is not reverse (NO in S312), the driving force distribution control unit 176 drives the driving force transmitted to the front wheels 120 and the driving transmitted to the rear wheels 122. The driving force is distributed so that the ratio with the force becomes the initial distribution (S322), and the vehicle control process is terminated.

  FIG. 8 is a flowchart showing the flow of the driving force distribution process. As shown in FIG. 8, the driving force distribution control unit 176 determines whether the front wheel 120 gets over the step B depending on whether the front wheel 120 is in contact with the step B and the amount of depression of the accelerator exceeds a predetermined value. It is determined whether the pedal has been operated, that is, whether there is a willingness to get over the front wheel (S310-2).

  If there is a willingness to get over the front wheel (YES in S310-2), the driving force distribution control unit 176 distributes the driving force to the front wheels 120 that are in contact with the step B with the maximum possible weight ratio. (S310-4), and the driving force distribution process ends.

  On the other hand, when there is no intention to get over the front wheel (S310-6), the driving force distribution control unit 176 determines whether the rear wheel 122 is in contact with the step B and whether the accelerator depression amount is equal to or greater than a predetermined value. It is determined whether the accelerator pedal has been operated in order for 122 to get over the step B, that is, whether or not there is an intention to ride over the rear wheel (S310-6). When there is a willingness to get over the rear wheel (YES in S310-6), the driving force distribution control unit 176 distributes the driving force to the rear wheel 122 that is in contact with the step with an allotment ratio as much as possible ( S310-8), the driving force distribution process ends. On the other hand, if there is no intention to ride over the rear wheel (NO in S310-6), the driving force distribution control unit 176 returns to the process of S322 (FIG. 7).

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the above-described embodiment, the case where the level difference detection unit 170 detects the level difference B based on the color image 200 has been described, but the level difference B may be detected by other means such as an infrared sensor.

  Further, in the above-described embodiment, the step contact determination unit 172 includes the front wheel 120 or the rear wheel 122 and the step B based on the distance to the step detected by the step detection unit 170 and the moving distance of the vehicle 100. Is detected. However, for example, the contact with the step B may be detected based on the air pressure of the front wheel 120 or the rear wheel 122.

  In the above-described embodiment, the overpass completion determination unit 182 determines the completion of overpass of the front wheel 120 or the rear wheel 122 in contact with the step B based on the moving distance of the vehicle 100. However, the completion of overtaking of the front wheel 120 or the rear wheel 122 in contact with the step B may be determined based on the driving torque or the inclination of the vehicle 100.

  In the above-described embodiment, when the front wheel 120 or the rear wheel 122 contacts the step B, the driving force distribution control unit 176 applies the maximum possible force to the front wheel 120 or the rear wheel 122 that contacts the step B. The limit driving force is distributed unevenly. However, when the front wheel 120 or the rear wheel 122 abuts on the step B, if the driving force is distributed to the front wheel 120 or the rear wheel 122 that is in contact with the step B, the maximum possible driving force is deviated. It is not necessary to distribute.

  The present invention can be used for a vehicle control device capable of distributing driving force to front wheels and rear wheels.

B Step 100 Vehicle 102 Engine (drive source)
104 Motor (drive source)
120 front wheel 122 rear wheel 140 vehicle control device 170 step detection unit 172 step contact determination unit 176 driving force distribution control unit 180 slip detection unit

Claims (5)

A vehicle control device for a vehicle capable of distributing driving force from a driving source to front wheels and rear wheels,
A step contact determination unit for determining whether the front wheel or the rear wheel is in contact with a step in the traveling direction of the vehicle;
A driving force distribution control unit that distributes the driving force to the front wheels or the rear wheels that are in contact with the step when the step contact determination unit determines that the front wheel or the rear wheel is in contact with the step; ,
A vehicle control device comprising: The driving force distribution control unit
2. The vehicle control device according to claim 1, wherein the driving force is distributed to a front wheel or a rear wheel that is in contact with the step so as to have a maximum distribution ratio that can be distributed. The driving force distribution control unit
The driving force is distributed to the front wheels or the rear wheels that are in contact with the step when the maximum driving force that can be output from the driving source is equal to or greater than a predetermined threshold value. Vehicle control device. A slip detector for detecting a slip of a front wheel or a rear wheel in contact with the step;
The driving force distribution control unit
When slip is detected by the slip detection unit, the driving force is distributed to the front wheel and the rear wheel so as to reduce the driving force with respect to the front wheel or the rear wheel contacting the step. The vehicle control device according to any one of claims 1 to 3.   5. The driving force is distributed to the front wheel and the rear wheel according to a predetermined initial distribution when the front wheel or the rear wheel passes the step. The vehicle control device according to item.

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