JP5477067B2 - Vehicle travel control device - Google Patents

Description

  The present invention relates to an apparatus for controlling the traveling of a vehicle by obtaining a driving force, a traveling line, and the like of the vehicle, and more particularly to an apparatus for performing control when traveling a corner portion.

Before and after the circular mosquitoes over blanking the carriageway, such as highways, there is a case where the intermediate relaxation curve connecting the straight line and the circle is inserted, which is called a clothoid curve smoothly by turning the steering wheel a curved section (Corner) is to be able to travel. Therefore, if it can drive | work along the clothoid curve in a corner part, a driver | operator's burden can be eased and stable driving | running | working can be performed.

  Therefore, for example, in the invention described in Patent Document 1, when a section of a clothoid curve is included in the corner portion and the road length of the section is stored as road map information, the section of the clothoid curve in the road map information The invention is configured to obtain the recommended vehicle speed based on the road length of the road and the road length of the constant curvature portion.

  Patent Document 2 discloses an invention configured to obtain a clothoid curve in a corner portion based on information on node points stored in a database of map data in order to perform driving force control suitable for road conditions. Is described.

JP 2006-331000 A JP 2005-214839 A

  In the invention described in Patent Document 1, the information on the clothoid curve set in the corner portion can be taken into the control of the vehicle speed, which may improve the running stability of the corner portion. For the control, it is a precondition that a section of a clothoid curve is provided in the corner portion and the road map information can be obtained. Therefore, in the case where the corner part where the clothoid curve section is not provided or the road map information cannot be obtained, the recommended vehicle speed for driving the corner part cannot be obtained, and there are many such corner parts. As a result, there is still room for improvement in order to drive stably on various roads.

  On the other hand, in the invention described in Patent Document 2, since the clothoid curve is set based on the information of the node point, it follows the clothoid curve even if the section of the clothoid curve and the information are not stored in the map information. It is possible to run or approximate to it. However, if the corner itself is not a curve along the clothoid curve, the clothoid curve is set to cross the actual road diagonally, so when traveling along the clothoid curve set in this way If this happens, a situation may occur in which the vehicle approaches the roadside, and the passenger may feel uncomfortable.

  The present invention has been made paying attention to the above technical problem, and an object of the present invention is to provide a traveling control device that facilitates traveling of a corner portion.

In order to achieve the above object, a first aspect of the present invention is a vehicle travel control device for controlling a vehicle to travel along a planned travel line, and a vehicle width for setting a minimum distance between the host vehicle and a roadside. and interval setting means in accordance with a clothoid constant prompts you distance between put that way end and the vehicle in front of the corner portion of the vehicle becomes the minimum distance or set in the vehicle width interval setting unit clothoid It is characterized by comprising a clothoid curve setting means for obtaining a curve and a control means for controlling the vehicle so as to travel along the clothoid curve obtained by the clothoid curve setting means.

According to a second aspect of the present invention, there is provided a vehicle travel control device that controls a vehicle to travel along a planned travel line, vehicle width interval setting means for setting a minimum distance between the host vehicle and a roadside, The clothoid curve at the corner of the vehicle is determined by the clothoid curve setting means for determining that the distance between the roadside at the corner and the vehicle is equal to or greater than the minimum distance set by the vehicle width interval setting means, and the clothoid curve setting means It was a control means for controlling so as to run along the clothoid curve, before Symbol vehicle width interval setting means, based on the interval of the vehicle in the traveling in the past corners and roadside its corners A vehicle travel control device including means for learning a minimum distance between a roadside and a host vehicle at a front corner portion.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the vehicle includes a vehicle capable of individually controlling driving torques of left and right wheels, and the control means is a clothoid curve obtained by the clothoid curve setting means. The vehicle travel control apparatus includes means for controlling the drive torque of the left and right wheels so as to travel along the road.

According to the present invention, in obtaining the clothoid curve at the front corner portion where traveling is expected, the distance between the roadside (particularly the inward roadside) and the vehicle in the vehicle width direction is equal to or greater than a preset minimum distance. A clothoid curve is obtained as follows. And it controls so that it may drive | work along the clothoid curve. Therefore, when driving in a corner where no clothoid curve is set or a corner where no data on the clothoid curve is available, the ride comfort is reduced by reducing fluctuations in the lateral acceleration in the transition region where the acceleration changes at the entrance and exit. In this case, since the host vehicle does not excessively approach the roadside or the road shoulder, it can be avoided or suppressed that the passenger feels uncomfortable.

Further, the distance of closest approach between the host vehicle and roadside when traveling along a clothoid curve set by the co over Na part, because learned on past travel, that the vehicle is too close to the roadside In addition, the approach distance can be prevented from becoming shorter than the distance experienced by the driver.

Furthermore, since the driving force of left and right wheels to travel along a controlled by clothoid curve, it is possible to perform traveling of the corner portion becomes easier, or comfortable driving.

It is a flowchart for demonstrating an example of the control performed by the traveling control apparatus which concerns on this invention. It is a figure which shows typically the positional relationship of a corner part and the own vehicle located in front of it. It is a diagram for demonstrating the calculation method of a clothoid curve. It is a schematic diagram which shows an example of the vehicle which can be made into object by this invention.

  The target vehicle in the present invention is a vehicle on which a driver performs a steering operation or acceleration / deceleration operation, and the most typical example is a four-wheeled vehicle equipped with a power source. In this type of vehicle, the turning ability (turning performance) differs depending on the driving torque at each wheel. For example, when the driving force of the rear wheels is larger than the driving force of the front wheels, it is easy to turn. Similarly, when the driving force is larger than the inner ring, the vehicle is easily turned. Therefore, in a vehicle that can individually control the drive torques of all four wheels, front, rear, left, and right, it is possible to more easily and easily control travel control during turning and straight travel.

  FIG. 4 schematically shows an example of a vehicle that can individually control the driving torque of the front, rear, left, and right wheels. The example shown here is a vehicle configured such that a driving force source such as an in-wheel motor is provided for each wheel, and each driving force source is individually controlled. That is, in FIG. 4, motors MFL, MFR, MRL, MRR are provided corresponding to the left and right front wheels WFL, WFR and the left and right rear wheels WRL, WRR, respectively. The output torque is transmitted to the corresponding wheels WFL, WFR, WRL, and WRR. Also, brakes BFL, BFR, BRL, BRR are provided for each wheel WFL, WFR, WRL, WRR in order to generate negative driving torque, that is, braking torque, in each wheel WFL, WFR, WRL, WRR. By individually controlling the brakes BFL, BFR, BRL, and BRR, the braking torque of each wheel WFL, WFR, WRL, and WRR can be individually controlled.

  Each of the motors MFL, MFR, MRL, and MRR is connected to a motor controller MCR. This motor controller MCR is composed of a capacitor, an inverter, a microcomputer, etc., and outputs each motor MFL, MFR, MRL, MRR individually according to a request based on a driver's operation or a request based on a vehicle state or a road condition. It is configured to control. Further, a navigation system NVS is connected to the motor controller MCR. This navigation system NVS stores map information and road information, uses a self-contained navigation system and GPS (Global Positioning System) to determine the position of the vehicle on the map data, and is automatically combined with the road information or map information. The position of the vehicle is displayed on a display or the like, and the control data is output to another computer such as a motor controller MCR.

  The control device according to the present invention for such a vehicle is based on the position information of the own vehicle obtained by the navigation system NVS, the road information around the own vehicle, and the road information of the front corner portion. It is configured to obtain a travel schedule line and to perform control for traveling the corner portion. The control can be performed by, for example, the motor controller MCR.

  FIG. 1 is a flowchart for explaining an example of the control. In the example shown here, a clothoid curve is obtained as a planned travel line, and the left and right driving torques are controlled so as to travel along the clothoid curve. This is an example of the configuration. In the example shown in FIG. 1, first, the position and vehicle speed of the host vehicle are acquired (step S1). The position of the host vehicle is obtained by the navigation system NVS, and the vehicle speed is obtained by a vehicle speed sensor mounted on the vehicle. Further, the radius R and lane width of the front corner portion are acquired (step S2). These may all be read from data stored in the navigation system NVS. The lane width is both the lane width at the current position of the host vehicle and the lane width at the corner.

  FIG. 2 schematically shows the positional relationship between the corner portion C and the host vehicle VH positioned in front of it. In FIG. 2, a thin broken line Lw indicates a travel line that follows the road shape, and a thick broken line Lt indicates a target travel line. A symbol W indicates a lane width. Based on the acquired position of the own vehicle and the vehicle width at that time at a predetermined time such as when the corner portion C is detected ahead, the end of the own vehicle and the lane (the inward side of the corner portion) Is calculated (step S3). In this case, data on the width of the own vehicle is required, but this may be stored in advance as data on the own vehicle. Further, a minimum distance Dc to be set between the host vehicle and the roadside (inside roadside) is obtained (step S4). This is preferably obtained by learning based on past data such as the average value of the distance between the host vehicle and the roadside at a corner portion that has traveled in the past. However, the present invention is not limited thereto, and may be a value manually input in advance or a value stored in advance in the form of a map or the like for each radius of curvature of the corner portion.

Next, the square of the clothoid constant A at the portion entering the front corner portion C is calculated (step S5), and the length Ltg of the clothoid curve is calculated (step S6). These can be obtained by the clothoid curve calculation method described below. FIG. 3 is a diagram showing the clothoid curve set at the entrance of the corner portion C in the XY coordinates, the amount of deviation d from the center line of the travel line in the vehicle width direction, and the road shape at the corner portion C. The clothoid constant A and its curve length Ltg are determined based on the curvature radius Rf determined by These relationships are expressed by equation (1).

なお、τは点（Ｘ，Ｙ）における接線の傾きである。 Assuming that the origin of the clothoid curve is the origin and the coordinates of the point where the radius of the travel line determined from the road shape is Rf are (X, Y), the above deviation d is expressed by the following equation (2).

Note that τ is the slope of the tangent at the point (X, Y).

According to the relational expression of clothoid, Y and τ are expressed by the following formulas (3) and (4).

When the above sin τ and cos τ are expanded by Maclaurin, the following equations (5) and (6) are obtained.

Therefore, the Y in the above equation (3) and the deviation d in the equation (4) are as in the equations (7) and (8).

Therefore, the clothoid constant A and the curve length Ltg can be approximated by the following equations (9) and (10) using the second term of the macrolin expansion.

  The difference (D−Dc) between the distance D from the host vehicle to the roadside during the straight running and the minimum distance Dc shown in FIG. 2 is substituted for the deviation d in the equations (9) and (10). Thus, the square of the clothoid constant A and the clothoid curve length Ltg in the front corner portion C are obtained.

Further, the length Le from the corner start point to the end point of the clothoid curve is calculated (step S7). Specifically, it can be approximated by the following equation (11).

  Next, the starting position of the clothoid curve is obtained (step S8). As described above, the length Le from the corner start point to the end point of the clothoid curve is calculated, and the coordinates of the end point of the clothoid curve are known as the points where the radius of curvature is Rf. The start point of the clothoid curve can be obtained by subtracting the length Le up to the end point of from the clothoid curve length Ltg. In other words, the starting point of the clothoid curve is a position in front of the corner starting point by a distance of (Ltg−Le = Ltg / 2).

  In order to control the driving force when traveling along the clothoid curve set as described above, first, it is determined whether or not the clothoid curve start point obtained in step S8 has been passed (step S8). S9). If a negative determination is made in step S9, the vehicle does not travel along the clothoid curve, so that it is not necessary to control the driving force in particular, and therefore the process returns without performing any particular control. On the other hand, when the host vehicle reaches the starting point of the clothoid curve and the determination in step S9 is affirmative, the travel time t of the clothoid curve section is calculated (step S10). When traveling at a constant vehicle speed V, the time t is obtained by dividing the length Ltg of the clothoid curve by the vehicle speed V.

The target yaw rate γ is calculated using the travel time t thus determined (step S11). When traveling on a clothoid curve at a constant vehicle speed, the lateral acceleration (lateral G) is
V ³ / A ² (m / s ³ )
It increases with a certain amount of change. Therefore, since the traveling time of the clothoid curve section is “t”, the lateral acceleration is V ³ / A ² × t (m / s ² ).
If it runs so that it becomes, it will run on a clothoid curve. Therefore, since the yaw rate is obtained by dividing the lateral acceleration by the vehicle speed, the target yaw rate γ in step S11 is
γ = V ² / A ² × t (rad / s)
Can be computed as

  In subsequent step S12, the drive torques of the left and right wheels are controlled so that the yaw rate generated in the vehicle becomes the target yaw rate γ. This control can be performed by feedback control based on the deviation between the detected actual yaw rate and the target yaw rate γ, or can be performed by feedforward control. As shown in FIG. 4, in a vehicle provided with motors MFL, MFR, MRL, MRR corresponding to the wheels WFL, WFR, WRL, WRR, the motors MFL, MFR, MRL, It is possible to travel along the clothoid curve by individually controlling the MRR. In this case, since the clothoid curve is set in consideration of the minimum distance Dc between the roadside and the roadside, the vehicle does not approach the roadside excessively, and the driver can be prevented from feeling uncomfortable. . And even if it is a case where it drive | works the corner part which does not have the section of a clothoid curve, since the driving line of a vehicle is set to a clothoid curve, it can drive | work comfortably, without a lateral acceleration changing suddenly.

  Here, the relationship between the above-described specific example and the present invention will be briefly described. The functional means for executing the control in step S4 shown in FIG. 1 corresponds to the vehicle width interval setting means in the present invention. The functional means for executing the control in step S7 corresponds to the clothoid curve setting means in the present invention, and the functional means for executing the control in steps S10 to S12 corresponds to the control means in the present invention.

  In the present invention, a new clothoid curve suitable for the host vehicle may be set as a scheduled travel line at the corner portion in front of the host vehicle. Therefore, the corner portion in front has a clothoid curve section. Not only when it is designed not to have, but even when it is designed to have a clothoid curve section, a clothoid curve suitable for the host vehicle is set as the scheduled driving line, and the driver's Discomfort can be eliminated or suppressed. Briefly describing this, the amount of deviation in the straight line portion in front of the corner portion is determined based on the length of the clothoid curve designed in the front corner portion and the radius of the corner portion. This is an operation opposite to the operation of the clothoid curve calculation method described with reference to FIG. 3 described above. A difference (D−Dc) between the distance D between the own vehicle and the roadside in the straight line portion and the minimum distance Dc between the own vehicle and the roadside that has been determined in advance by learning or the like is added to the deviation amount calculated in this way. The amount of deviation of the clothoid curve. The clothoid constant and the clothoid curve length are newly obtained from the new deviation amount and the above-described expressions (9) and (10), and a new control target of the own vehicle is set based on the clothoid constant and the clothoid curve length. By doing so, it is possible to set a clothoid curve suitable for the traveling of the host vehicle, which is different from the clothoid curve designed in the front corner portion, and to perform corner traveling suitable for the host vehicle.

  As described above, in the control device according to the present invention, it is possible to perform control using the distance (distance) between the host vehicle and the roadside obtained when the corner portion traveled in the past. The distance (distance) can be determined based on the position of the vehicle by the navigation system NVS and the road information stored in the navigation system NVS. In addition, millimeter waves, microwaves, radar, lasers, super It is good also as actually measuring using a sound wave etc.

  Further, in the above specific example, as an example of controlling the driving torque of the left and right wheels based on the target yaw rate as the control for traveling along the calculated clothoid curve, the traveling control in this invention In addition to controlling the drive torque, the planned travel line based on the calculated clothoid curve is displayed on the display, windscreen, etc. in the navigation system NVS, thereby prompting the driver to travel along the clothoid curve. May be. In addition, the target vehicle in the present invention may be a vehicle having two front and rear wheels as drive wheels. In that case, in order to generate a yaw for traveling along a clothoid curve, What is necessary is just to control the driving force of a driving wheel to magnitude, or just to perform such control of driving torque in conjunction with control of a steering angle.

  In the present invention, it is not particularly necessary that the distance between the host vehicle and the roadside at the corner portion coincides with the above-mentioned minimum distance, and it may be more than the minimum distance.

  WFL, WFR ... front wheel, WRL, WRR ... rear wheel, MFL, MFR, MRL, MRR ... motor, BFL, BFR, BRL, BRR ... brake, MCR ... motor controller, NVS ... navigation system, C ... corner part, VH ... Own vehicle.

Claims (3)

In a vehicle travel control device for controlling a vehicle to travel along a travel schedule line,
Vehicle width interval setting means for setting a minimum distance between the host vehicle and the roadside;
Clothoid curve to determine the clothoid curve in accordance with the clothoid constant prompts it distances between put that way end and the vehicle in front of the corner portion of the vehicle becomes the minimum distance or set in the vehicle width interval setting means Setting means;
And a control means for controlling the vehicle to run along the clothoid curve determined by the clothoid curve setting means. In a vehicle travel control device for controlling a vehicle to travel along a travel schedule line,
Vehicle width interval setting means for setting a minimum distance between the host vehicle and the roadside;
Clothoid curve setting means for obtaining a clothoid curve at a corner portion in front of the host vehicle so that a distance between the roadside and the host vehicle at the corner portion is equal to or greater than a minimum distance set by the vehicle width interval setting means;
Control means for controlling the vehicle to travel along the clothoid curve determined by the clothoid curve setting means;
With
Before SL vehicle width interval setting means, based on the interval of the vehicle in the traveling in the past corners and roadside its corners, a means for learning a minimum distance between the roadside and the vehicle in front of the corner vehicles running control apparatus for you comprising. The vehicle includes a vehicle that can individually control the driving torque of the left and right wheels,
3. The vehicle according to claim 1, wherein the control unit includes a unit that controls driving torques of left and right wheels so as to travel along the clothoid curve obtained by the clothoid curve setting unit. Travel control device.

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