JP6222477B2 - Vehicle travel line generator - Google Patents

Description

  The present invention relates to a vehicle travel line generation device, and more particularly, to a travel line generation device that generates a vehicle travel line from entry to exit from a curve.

2. Description of the Related Art Conventionally, techniques for generating a travel line of a vehicle and performing driving support so that the vehicle travels along the travel line or performing automatic driving are known.
For example, in Patent Document 1, in order to contribute to improvement in fuel consumption, a traveling locus is obtained by performing a convergence calculation using an evaluation function including an evaluation of the total amount of brake deceleration heat dissipation while satisfying a constraint condition including a road boundary condition. Describes a traveling locus generation method for generating a traveling locus that suppresses deceleration as much as possible and suppresses energy loss due to heat dissipation by deriving the above.
Further, Patent Document 2 discloses that the entire travel path is derived by performing a convergence operation by an evaluation function including evaluation of speed dispersion and deriving a travel locus in a state where constraint conditions including a road boundary condition are satisfied. Describes a method for generating a traveling locus in which acceleration / deceleration is suppressed as much as possible, a traveling locus with less variation in vehicle speed is generated, and an increase in air resistance due to an increase in maximum speed is suppressed.

JP 2009-113523 A JP 2009-115465 A

  By the way, when the vehicle travels on a curve, a slip angle is generated in the tire, and a lateral force corresponding to the slip angle is generated. A component of the lateral force in the vehicle front-rear direction is a resistance force (cornering resistance) that acts toward the rear of the vehicle. Therefore, in order to generate a travel line with excellent fuel efficiency from entry to exit to a curve, it is desirable to generate a travel line that suppresses cornering resistance generated in the tire.

  However, in the conventional method described above, no consideration is given to the cornering resistance generated in the tire during curve driving, so the generated travel locus does not necessarily suppress the cornering resistance of the tire, and fuel consumption There is room for improvement.

  The present invention has been made in order to solve the above-described problems of the prior art, and provides a vehicle travel line generation device capable of generating a travel line excellent in fuel consumption from entry to exit from a curve. The purpose is to provide.

In order to achieve the above object, a vehicle travel line generation device according to the present invention is a travel line generation device that generates a vehicle travel line from entry to exit to a curve, and relates to the planar shape and gradient of the curve. Curve shape information acquisition means for acquiring shape information, target yaw rate setting means for setting the target yaw rate of the vehicle between the start position and end position of the curve specified based on the shape information related to the planar shape of the curve, And a target yaw rate correction unit that corrects the target yaw rate to be decreased in an ascending gradient section and corrects the target yaw rate to be increased in a descending gradient section.
In the present invention configured as described above, in the ascending slope section of the curve, the tire cornering force is reduced by reducing the front wheel load, but the target yaw rate correcting means corrects the target yaw rate to the decreasing side. As a result, an increase in the steering angle required to achieve the target yaw rate can be suppressed, and thereby an increase in cornering resistance can be suppressed. Also, in the downward slope section of the curve, the tire cornering force increases as the load on the front wheel increases, but the target yaw rate correction means corrects the target yaw rate to the increase side to achieve the target yaw rate. While maintaining the required steering angle, it is possible to realize faster turning, thereby compensating for a decrease in the target yaw rate in the uphill section. Therefore, it is possible to generate a travel line with excellent fuel efficiency from entering the curve to exiting without extending the time required for passing the curve.

In the present invention, it is preferable that the vehicle travel line generation device further decreases the target acceleration in the traveling direction of the vehicle between the start position and the end position of the curve as it goes from the start position to the end position of the curve. Target acceleration setting means for setting so as to monotonously increase from the value of the vehicle to the positive value, and the target yaw rate setting means determines the target yaw rate of the vehicle between the start position and end position of the curve from the start position of the curve. It is set so as to monotonously increase toward an intermediate position between the start position and end position of the curve and monotonously decrease from this intermediate position toward the end position of the curve.
In the present invention configured as described above, the target yaw rate setting means steers by suppressing the target yaw rate to a small value in the vicinity of the start position and end position of the curve where the steering angle tends to increase when the vehicle speed is high and the target yaw rate is increased. In the vicinity of an intermediate position where the increase in the angle is suppressed and the increase in the steering angle can be suppressed even if the vehicle speed is low and the target yaw rate is increased, the target yaw rate is set to a large value and the vehicle is efficiently turned so that it can pass through the curve. The cornering resistance generated in the tire can be reduced without extending the time, and the cornering resistance generated in the tire can be used for deceleration of the vehicle when the target acceleration is negative. Loss can be reduced, which makes it possible to improve fuel economy from entry to exit The traveling line can be generated.

In the present invention, it is preferable that the target yaw rate setting means sets the minimum curvature radius position of the curve as the intermediate position.
In the present invention configured as described above, a target yaw rate can be set in accordance with the shape of the curve, and a traveling line capable of reducing energy loss due to cornering resistance while smoothly turning the curve is generated. be able to.

In the present invention, it is preferable that the target acceleration setting means sets the target acceleration at the intermediate position to zero.
In the present invention configured as described above, an increase in the steering angle can be suppressed by minimizing the vehicle speed at an intermediate position where the target yaw rate becomes the maximum value, and energy loss due to cornering resistance is reduced while smoothly turning the curve. A travel line that can be generated can be generated.

  According to the vehicle travel line generation device of the present invention, it is possible to generate a travel line excellent in fuel consumption from entry to exit to curve.

It is a block diagram which shows the electric constitution of the vehicle carrying the traveling line production | generation apparatus of the vehicle by embodiment of this invention. It is a top view which shows an example of the curve which the driving line production | generation apparatus of the vehicle by embodiment of this invention produces | generates a driving line. It is a flowchart of the travel line production | generation process which the travel line production | generation apparatus of the vehicle by embodiment of this invention performs. FIG. 4 is a diagram illustrating an acceleration / deceleration control curve and a yaw rate control curve set by the vehicle travel line generation device according to the embodiment of the present invention, where (a) is a line showing the yaw rate control curve set by the target yaw rate setting unit. (B) is a diagram showing an acceleration / deceleration control curve set by the target acceleration / deceleration setting unit, (c) is a vehicle traveling along the curve according to the yaw rate control curve of (a) and the acceleration / deceleration control curve of (b). FIG. 4D is a diagram showing cornering resistance generated in the tire in the case of the above, and FIG. 4D is a diagram showing energy loss generated by the cornering resistance shown in FIG. FIG. 5A is a diagram showing the yaw rate control curve of FIG. 4A corrected according to the curve gradient; FIG. 5A is a diagram showing the curve gradient; and FIG. 4B is corrected according to the curve gradient. It is a diagram which shows the yaw rate control curve of Fig.4 (a).

Hereinafter, a vehicle travel line generation device according to an embodiment of the present invention will be described with reference to the accompanying drawings.
First, a vehicle equipped with a vehicle travel line generation device according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing an electrical configuration of a vehicle equipped with a vehicle travel line generation device according to an embodiment of the present invention.

  As shown in FIG. 1, the code | symbol 1 shows the vehicle carrying the traveling line production | generation apparatus of the vehicle by this embodiment. The vehicle 1 includes an outside camera 2 that captures the front of the vehicle 1, a map database 4 that stores shape information related to the planar shape and gradient of the road, a GPS 6 (Global Positioning System), a vehicle speed sensor 8 that detects the vehicle speed, and the vehicle 1. An acceleration sensor 10 that detects acceleration in the traveling direction and a yaw rate sensor 12 that detects the yaw rate of the vehicle 1 are included. Image data taken by the outside camera 2, road shape information acquired from the map database 4, position information acquired by the GPS 6, and detection data detected by each sensor are sent to the ECU 14 (vehicle travel line generation device). Is output.

  The ECU 14 includes a curve shape information acquisition unit 16 that acquires shape information regarding the planar shape and gradient of the curve, a maximum lateral acceleration acquisition unit 18 that acquires the maximum lateral acceleration that the vehicle 1 can generate while turning, and a curve A target acceleration / deceleration setting unit 20 that sets a target acceleration / deceleration in the traveling direction of the vehicle 1 between the start position and the end position, and a target yaw rate that sets the target yaw rate of the vehicle 1 between the start position and the end position of the curve. A setting unit 22, a target yaw rate correction unit 24 for correcting the target yaw rate set by the target yaw rate setting unit 22, a generation line evaluation unit 26 for evaluating the generated travel line, an engine 28 of the vehicle 1 according to the target acceleration, and The acceleration / deceleration control unit 32 that controls the brake 30 and the electric power of the vehicle 1 according to the target acceleration and the target yaw rate. And a steering torque controller 36 which controls the steering 34.

  These curve shape information acquisition unit 16, maximum lateral acceleration acquisition unit 18, target acceleration setting unit, target yaw rate setting unit 22, target yaw rate correction unit 24, generation line evaluation unit 26, acceleration / deceleration control unit 32, and steering torque controller 36 Is for storing a CPU, various programs interpreted and executed on the CPU (including a basic control program such as an OS and an application program that is activated on the OS and realizes a specific function), and programs and various data And a computer having an internal memory such as a ROM or a RAM.

Next, acceleration / deceleration control in the traveling direction of the vehicle 1 performed by the travel line generation device of the vehicle 1 will be described with reference to FIGS.
FIG. 2 is a plan view showing an example of a curve for generating a travel line by the travel line generation device for the vehicle 1 according to the embodiment of the present invention, and FIG. 3 is a travel line generation device for the vehicle 1 according to the embodiment of the present invention. FIG. 4 is a diagram showing an acceleration / deceleration control curve and a yaw rate control curve set by the traveling line generation device of the vehicle 1 according to the embodiment of the present invention. FIG. 5 is a diagram showing the yaw rate control curve of FIG. 4 corrected according to the slope of the curve.

  First, as illustrated in FIG. 2, in the present embodiment, a case where the travel line generation device of the vehicle 1 generates the travel line 40 of the vehicle 1 from entering the left curve 38 to exiting will be described as an example. The curve 38 shown in FIG. 2 is formed by combining, for example, a clothoid curve, an arc, a parabola, and the like.

  Next, the travel line generation process shown in FIG. 3 is a process of generating the travel line 40 of the vehicle 1 from entering the curve 38 to exiting, and is executed after the ignition switch of the vehicle 1 is turned on.

  As shown in FIG. 3, when the travel line generation process is started, in step S <b> 1, the curve shape information acquisition unit 16 converts map data including the shape information of the road for which the travel line 40 is generated into map database. Read from 4. The road for which the travel line 40 is generated is, for example, a road constituting a travel route set in advance by the navigation system.

Next, in step S2, the curve shape information acquisition unit 16 acquires the shape of the curve 38 that generates the travel line 40 based on the map data read in step S1.
For example, the curve shape information acquisition unit 16 specifies a range in which the radius of curvature R is 300 m or less in the travel route of the vehicle 1 from the map data read in step S <b> 1 as the curve 38 that is the generation target of the travel line 40. And the curvature radius in each node of the specified curve 38 is acquired based on map data.

Further, in step S3, the curve shape information acquisition unit 16 acquires the road surface gradient in the curve 38, which is the generation target of the travel line 40 specified in step S2, from the map data read in step S1.
For example, the curve shape information acquisition unit 16 acquires the road surface gradient at each node of the curve 38 that is the generation target of the travel line 40 specified in step S2 based on the map data.

  Alternatively, instead of the above-described steps S1 to S3, the curve shape information acquisition unit 16 specifies the curvature radius R of the road ahead of the vehicle 1 based on the image data in front of the vehicle 1 captured by the outside camera 2, and the curvature thereof. When the radius R is 300 m or less, the road may be specified as the curve 38 that is the generation target of the travel line 40. In this case, the curve shape information acquisition unit 16 sets nodes at regular intervals (for example, 5 m intervals) on the center line of the specified curve 38 based on the image data in front of the vehicle 1 captured by the outside camera 2. Obtain the radius of curvature and the road gradient at.

Next, in step S4, the target yaw rate correction unit 24 estimates a change in the longitudinal load of the vehicle 1 due to the road gradient of the curve 38 acquired in step S3.
For example, the target yaw rate correction unit 24 determines the position of the vehicle 1 at each node of the curve 38 based on the position of the center of gravity of the vehicle 1 and the road surface gradient at each node of the curve 38 that is the generation target of the travel line 40 acquired in step S3. The load W _fslope applied to the front wheel is calculated by the following formula.
W _fslope = mg (l _r cos θ−hsin θ) / l (1)
Here, m is the vehicle weight, g is the gravitational acceleration, l is the distance between the front and rear axes, l _r is the distance between the rear axis and the center of gravity, h is the height of the center of gravity, and θ is the road gradient.

Next, in step S5, the target yaw rate correction unit 24 determines a yaw rate correction coefficient K _slope used when correcting the target yaw rate based on the longitudinal load distribution of the vehicle 1 due to the road surface gradient of the curve 38 estimated in step S4. To do.
For example, the target yaw rate correction unit 24 calculates the yaw rate correction coefficient K _slope at each node of the curve 38 by the following equation.
K _slope = (l _r cos θ−h sin θ) / l _r (2)
That is, the yaw rate correction coefficient K _slope is less than 1 when the road surface is uphill (θ is positive), and is greater than 1 when the road surface is downhill (θ is negative).

Next, in step S6, the target acceleration setting unit 20, acceleration G _Xent in the traveling direction of the vehicle 1 at the turning start position, acceleration G _xExt in the traveling direction of the vehicle 1 at the pivot end position, and the vehicle 1 A maximum lateral acceleration G _ymax that can be generated during a turn is determined.
For example, the target acceleration / deceleration setting unit 20 determines the maximum lateral acceleration G (for example, 4 m / s ² ) that can be generated in the vehicle 1 while turning at a constant vehicle speed in the linear region of the tire friction characteristics. _Determine as _ymax . Further, the acceleration / deceleration _Gxent in the traveling direction of the vehicle 1 at the turning start position is set to a maximum deceleration (for example, 4 m / s ² ) having a magnitude equal to the maximum lateral acceleration _Gymax, and the traveling direction of the vehicle 1 at the turning end position is set. _{Is set} to the maximum acceleration (for example, 2 m / s ² ) that the vehicle 1 can achieve.

Next, in step S7, the target acceleration setting unit 20, a vehicle speed (initial speed) V _ent at the turning start position, the acceleration G _x in the traveling direction of the vehicle 1 between the start and end of the curve 38 Set the intermediate position to zero. Further, the target yaw rate setting unit 22 sets a maximum value γ _max of the target yaw rate between the start position and the end position of the curve 38.
For example, the target acceleration / deceleration setting unit 20 sets the vehicle speed when the maximum lateral acceleration G _ymax is generated at the curvature radius minimum position of the curve 38 as the initial value of the initial speed V _ent . The target acceleration setting unit 20, the radius of curvature minimum position of the curve 38, to set the acceleration G _x in the traveling direction of the vehicle 1 as the initial value of the intermediate position to 0. In addition, the target yaw rate setting unit 22 sets the yaw rate when the maximum lateral acceleration G _ymax is generated at the curvature radius minimum position of the curve 38 as the initial value of the maximum value γ _max of the target yaw rate.

Next, in step S8, the target acceleration / deceleration setting unit 20 acquires the shape information of the curve 38 acquired in step S2, the acceleration / deceleration _{Gxent in} the traveling direction of the vehicle 1 at the turning start position determined in step S6, and the turning end position. the traveling direction of the acceleration G _xExt of the vehicle 1, and, based on the acceleration G _x set at step S7 in the intermediate position to 0 and sets the acceleration control curve from the pivot start position to the turning end position.
Specifically, the target acceleration / deceleration setting unit 20 adjusts the curve 38 so that the deceleration in the traveling direction of the vehicle 1 monotonously decreases from G _xext to 0 in the section from the turning start position to the intermediate position in the curve 38. The acceleration / deceleration control curve is set so that the acceleration in the traveling direction of the vehicle 1 monotonically increases from 0 to G _xext in the section from the intermediate position to the turn end position. That is, when the acceleration when the vehicle 1 accelerates in the traveling direction is positive and the acceleration when the vehicle 1 decelerates is negative, the acceleration in the traveling direction of the vehicle 1 starts from a negative value as it goes from the start position to the end position of the curve 38. Set the acceleration / deceleration control curve to monotonically increase to a positive value.

Further, in step S8, the target yaw rate setting unit 22 determines from the turning start position to the turning end position based on the shape information of the curve 38 acquired in step S2 and the maximum value γ _max of the target yaw rate set in step S7. Set the yaw rate control curve.
Specifically, the target yaw rate setting unit 22 makes the target yaw rate monotonically increase from 0 to γ _max in the section from the turning start position to the intermediate position on the curve 38, and from the intermediate position on the curve 38 to the turning end position. The target yaw rate is set so as to monotonously decrease from γ _max to 0 in the interval up to.

Subsequently, in step S9, the target yaw rate correction unit 24 corrects the yaw rate control curve set in step S8 based on the yaw rate correction coefficient determined in step S5.
Specifically, the target yaw rate correction unit 24 multiplies the yaw rate control curve set in step S8 by the yaw rate correction coefficient K _slope determined in step S5. As described above, the yaw rate correction coefficient K _slope is less than 1 when the road surface is uphill (θ is positive) and is greater than 1 when the road surface is downhill (θ is negative). The target yaw rate correction unit 24 performs correction so as to decrease the target yaw rate in the upward gradient section of the curve 38 and corrects the target yaw rate to increase in the downward gradient section.

  In this way, in step S8, the acceleration / deceleration control curve and the yaw rate control curve from the turning start position to the turning end position are set, and in step S9, the yaw rate control curve is corrected, so that the entry to the curve 38 is made to escape. A travel line 40 of the vehicle 1 is generated.

Next, in step S10, the generation line evaluation unit 26 represents the travel line 40 of the vehicle 1 represented by the acceleration / deceleration control curve set in step S8 and the yaw rate control curve set in step S8 and corrected in step S9. An evaluation value for evaluating is calculated.
For example, the generation line evaluation unit 26 calculates an evaluation function J defined by the following formula.
J = (|| ^R P || -R) ² + ( ^O y _ext ) ² + ( ^O Ψ _ext ) ²
Here, ^R P is the shortest distance from the center of the arc forming the lane inner end of the curve 38 to the traveling line 40 of the vehicle 1, R is the radius of the arc forming the lane inner end of the curve 38, ^O _y (γ _{= 0, t ≠ 0)} is the distance from the outer lane edge to the travel line 40 of the vehicle 1 at the turn end position, and ^O Ψ _ext is the direction of the outer lane edge at the turn end position and the direction of the travel line 40 of the vehicle 1 Is an angle.

  Next, in step S11, the generation line evaluation unit 26 determines whether or not the evaluation function J calculated in step S10 is less than a preset target value. This target value is set as a value obtained when the generated travel line 40 is located between the lane inner end and the lane outer end of the curve 38.

As a result, if the evaluation function J calculated in step S10 is not less than the preset target value (is greater than or equal to the target value), the process returns to step 7 and the target acceleration / deceleration setting unit 20 determines the initial speed V _{ent at the} turning start position. and an intermediate position of the acceleration G _x in the traveling direction of the vehicle 1 to 0 between the start and end positions of curve 38, the evaluation function J is set again so as to approach the target value, the target yaw rate setting unit 22 resets the maximum value γ _max of the target yaw rate between the start position and the end position of the curve 38 so that the evaluation function J approaches the target value.
Thereafter, by repeating steps S7 to S11, the convergence calculation is performed so that the evaluation function J is less than the preset target value in step S11.

  In step S11, when the evaluation function J is less than the preset target value, the travel line generation device ends the travel line generation process.

When performing driving assistance or performing automatic driving so that the vehicle 1 travels along the travel line 40 generated by the travel line generation process described above, the acceleration / deceleration control unit 32 performs step S7 of the travel line generation process. The engine 28 and the brake 30 of the vehicle 1 are controlled so as to enter the curve 38 at the initial speed V _ent determined in _Step 1, and after the vehicle 1 enters the curve 38, the actual acceleration of the vehicle 1 detected by the acceleration sensor 10 is detected. Based on the above, the engine 28 and the brake 30 of the vehicle 1 are controlled so as to generate the acceleration / deceleration of the acceleration / deceleration control curve set in step S8 of the travel line generation process. In addition, the steering controller generates the yaw rate of the yaw rate control curve set in step S8 of the travel line generation process and corrected in step S9 based on the actual yaw rate of the vehicle 1 detected by the yaw rate sensor 12. The electric power steering 34 is controlled.

Next, an acceleration / deceleration control curve and a yaw rate control curve set by the travel line generation device of the vehicle 1 will be described with reference to FIGS. 4 and 5.
FIG. 4 is a diagram illustrating an acceleration / deceleration control curve and a yaw rate control curve set by the travel line generation device for the vehicle 1 according to the embodiment of the present invention. FIG. 4 (a) is set by the target yaw rate setting unit 22. FIG. 4B is a diagram showing the acceleration / deceleration control curve set by the target acceleration / deceleration setting unit 20, and FIG. 4C is a diagram showing the vehicle 1 in FIG. 4A. FIG. 4D is a diagram showing the cornering resistance generated in the tire when traveling on the curve 38 in accordance with the yaw rate control curve and the acceleration / deceleration control curve of FIG. 4B, and FIG. 4D is the cornering resistance shown in FIG. It is a diagram which shows the generated energy loss. In each diagram of FIG. 4, a solid line indicates a value by the travel line 40 generated by the travel line generation device, and a dotted line indicates a required time that is the same as the required time by the travel line 40 generated by the travel line generation device. The values are shown when the same curve 38 is turned in a steady circle (constant vehicle speed and constant yaw rate). 4 represents the distance from the turning start position on the curve 38, the vertical axis in FIG. 4A represents the counterclockwise yaw rate, and the vertical axis in FIG. 4B represents the vertical axis. Acceleration in the traveling direction of the vehicle 1 (acceleration is positive, deceleration is negative), the vertical axis in FIG. 4 (c) indicates the cornering resistance generated in the tire, and the vertical axis in FIG. 4 (d) is generated by the cornering resistance. Indicates energy loss.
5 is a diagram showing the yaw rate control curve of FIG. 4A corrected according to the slope of the curve 38, FIG. 5A is a diagram showing the slope of the curve 38, and FIG. 4B is a diagram showing the yaw rate control curve of FIG. 4A corrected according to the slope of the curve 38. FIG. 5 represents the distance from the turning start position in the curve 38, and the vertical axis in FIG. 5A represents the slope of the curve 38 (upward is positive and downward is negative). The vertical axis of (b) indicates the counterclockwise yaw rate.

  First, as shown in FIGS. 4A and 4B, in steady circle turning, the yaw rate is constant from the turning start position to the turning end position on the curve 38, and the acceleration / deceleration in the traveling direction of the vehicle 1 is constant at 0. It is. Since the steering angle is constant in this steady circle turning, a constant cornering resistance is generated in the tire from the turning start position to the turning end position as shown in FIG. In this case, in order to maintain a constant vehicle speed in steady circle turning, it is necessary to generate a driving force that cancels cornering resistance, which results in energy loss. As a result, as shown in FIG. 4 (d), the energy loss caused by the cornering resistance continues to increase from the turning start position to the turning end position.

On the other hand, in the yaw rate control curve set by the target yaw rate setting unit 22, as shown in FIG. 4A, the target yaw rate monotonously increases from 0 to γ _max in the section from the turning start position to the intermediate position in the curve 38. In addition, the target yaw rate monotonously decreases from γ _max to 0 in the section from the intermediate position on the curve 38 to the turning end position.
Further, in the acceleration / deceleration control curve set by the target acceleration / deceleration setting unit 20, the deceleration in the traveling direction of the vehicle 1 in the section from the turning start position to the intermediate position in the curve 38 is shown in FIG. monotonically decreases from G _xExt to 0, and the acceleration in the traveling direction of the vehicle 1 in a section to pivot the end position from an intermediate position in the curve 38 increases monotonically from 0 to G _xExt. That is, when the acceleration when the vehicle 1 is accelerated in the traveling direction is positive and the acceleration when the vehicle 1 is decelerated is negative, the acceleration in the traveling direction of the vehicle 1 monotonously increases from the start position of the curve 38 toward the end position.

  In this case, the cornering resistance generated in the tire monotonously increases in the section from the turning start position to the intermediate position with the change of the steering angle corresponding to the target yaw rate, and the turning ends from the intermediate position in the curve 38. It decreases monotonously in the section up to the position.

Here, the cornering resistance shown in FIG. 4C is a section below the braking force required to achieve the deceleration in the acceleration / deceleration control curve shown in FIG. 4B (from the turning start position in FIG. 4). In the section up to the position A), the cornering resistance can be used for deceleration of the vehicle 1, so that no energy loss occurs in this section.
Further, as shown in FIG. 4 (c), the maximum value of the cornering resistance generated in the tire in accordance with the yaw rate set by the target yaw rate setting unit 22 is larger than the cornering resistance generated in the steady circular turning. The cornering resistance shown in (c) is greater than or equal to the braking force required to achieve the deceleration in the acceleration / deceleration control curve shown in FIG. 4B, or the acceleration is positive in the acceleration / deceleration control curve (in FIG. 4). The total amount of cornering resistance generated in the tire in the section from the position A to the turn end position) is smaller than the total amount of cornering resistance generated in the same section in the case of steady circular turning. Therefore, as shown in FIG. 4D, the energy loss due to the cornering resistance that occurs when the vehicle 1 travels along the curve 38 according to the acceleration / deceleration control curve and the yaw rate control curve set by the travel line generator is a steady circle. Compared to energy loss when turning, it is greatly reduced.

Further, as shown in FIG. 5, the target yaw rate correction unit 24 corrects the yaw rate control curve set by the target yaw rate setting unit 22 so as to decrease the target yaw rate in the upward slope section of the curve 38, and In the gradient section, correction is made to increase the target yaw rate.
That is, in the ascending slope section of the curve 38, the tire cornering force decreases as the front wheel load decreases. However, the target yaw rate is corrected to the decreasing side, so that it is necessary to achieve the target yaw rate. An increase in steering angle is suppressed, thereby suppressing an increase in cornering resistance.
On the other hand, in the downward slope section of the curve 38, the tire cornering force increases as the front wheel load increases. However, the target yaw rate is corrected to the increasing side, and is necessary to achieve the target yaw rate. Faster turning can be realized while maintaining the steering angle, and this can compensate for a decrease in the target yaw rate in the uphill section.

Next, further modifications of the embodiment of the present invention will be described.
In the above-described embodiment, the vehicle 1 equipped with the travel line generation device of the vehicle 1 has been described as an example in which an internal combustion engine 28 such as a gasoline engine or a diesel engine is mounted as a power source. Instead, or together with these engines 28, a battery and a motor may be mounted on the vehicle 1 as a power source. In this case, the acceleration / deceleration control unit 32 controls the motor and the brake 30 of the vehicle 1 according to the acceleration / deceleration control curve set in the acceleration / deceleration control process.

In the embodiment described above, the target acceleration / deceleration setting unit 20 sets the target acceleration / deceleration so that the acceleration / deceleration control curve is linear, but the acceleration in the traveling direction of the vehicle 1 ends from the start position of the curve 38. The acceleration / deceleration control curve may set the target acceleration / deceleration in a curved shape such as a cos curve as long as it monotonously increases toward the position.
In the above-described embodiment, the target yaw rate setting unit 22 sets the target yaw rate so that the yaw rate control curve is linear, but the acceleration in the traveling direction of the vehicle 1 is changed from the start position of the curve 38 to the end position. The target acceleration / deceleration may be set in a curve shape such as a cos curve as long as it increases monotonously as it goes to.

  Next, effects of the travel line generation device for the vehicle 1 according to each of the above-described embodiments of the present invention and modifications of the embodiments of the present invention will be described.

  First, the target acceleration setting unit monotonously changes the target acceleration in the traveling direction of the vehicle 1 between the start position and the end position of the curve 38 from a negative value to a positive value as it goes from the start position to the end position of the curve 38. The target yaw rate setting unit 22 sets the target yaw rate of the vehicle 1 between the start position and the end position of the curve 38 between the start position and the end position of the curve 38 from the start position of the curve 38. The curve 38 is monotonically increased toward the intermediate position and monotonically decreased from the intermediate position toward the end position of the curve 38. Therefore, the start of the curve 38 where the steering angle easily increases when the vehicle speed is high and the target yaw rate is increased. In the vicinity of the position and end position, the target yaw rate is suppressed to a small value to suppress an increase in the steering angle, the vehicle speed is decreased and the target yaw rate is increased By increasing the target yaw rate in the vicinity of the intermediate position where the increase of the steering angle can be suppressed, the cornering resistance generated in the tire can be reduced without increasing the time required for passing the curve 38, and the target acceleration is negative. In the interval of the value, the cornering resistance generated in the tire can be used for deceleration of the vehicle 1, thereby reducing the energy loss due to the cornering resistance. Therefore, it is possible to generate the travel line 40 having excellent fuel efficiency from entering the curve 38 to exiting.

  Further, the target yaw rate setting unit 22 sets the minimum curvature radius position of the curve 38 as an intermediate position, so that the target yaw rate can be set in accordance with the shape of the curve 38, and the curve 38 is smoothly turned by the cornering resistance. The traveling line 40 capable of reducing energy loss can be generated.

  Further, since the target acceleration / deceleration setting unit 20 sets the target acceleration at the intermediate position to 0, the vehicle speed can be minimized at the intermediate position where the target yaw rate becomes the maximum value, and the increase of the steering angle can be suppressed. It is possible to generate the travel line 40 capable of reducing energy loss due to cornering resistance while smoothly turning.

  Further, the target yaw rate correction unit 24 corrects the target yaw rate to decrease in the upward gradient section of the curve 38 and corrects the target yaw rate to increase in the downward gradient section. In this section, the cornering force of the tire decreases as the load on the front wheels decreases, but by correcting the target yaw rate to the decreasing side, it is possible to suppress an increase in the steering angle necessary to achieve the target yaw rate, Thereby, the increase in cornering resistance can be suppressed. In the downward slope section of the curve 38, the tire cornering force increases as the load on the front wheel increases, but the steering necessary to achieve the target yaw rate by correcting the target yaw rate to the increasing side. A faster turn can be achieved while maintaining the angle, which can compensate for a decrease in the target yaw rate in the uphill section. Therefore, it is possible to generate the travel line 40 with excellent fuel efficiency from entering the curve 38 to exiting without extending the time required for the curve 38 to pass.

1 Vehicle 2 Outside Camera 4 Map Database 6 GPS
8 Vehicle speed sensor 10 Acceleration sensor 12 Yaw rate sensor 14 ECU
16 Curve shape information acquisition unit 18 Maximum lateral acceleration acquisition unit 20 Target acceleration / deceleration setting unit 22 Target yaw rate setting unit 24 Target yaw rate correction unit 26 Generation line evaluation unit 28 Engine 30 Brake 32 Acceleration / deceleration control unit 34 Electric power steering 36 Steering torque controller 38 curve 40 driving line

Claims (4)

A travel line generation device that generates a travel line of a vehicle from entry to exit to a curve,
Curve shape information acquisition means for acquiring shape information regarding the planar shape and gradient of the curve;
Target yaw rate setting means for setting a target yaw rate of the vehicle between the start position and end position of the curve specified based on the shape information relating to the planar shape of the curve;
The vehicle has a target yaw rate correction unit that corrects the target yaw rate so as to decrease in an ascending section of the curve and corrects the target yaw rate to increase in a descending section. Travel line generator. Further, a target for setting the target acceleration in the vehicle traveling direction between the start position and the end position of the curve so as to monotonously increase from a negative value to a positive value as it goes from the start position to the end position of the curve. Having acceleration setting means;
The target yaw rate setting means monotonously increases the target yaw rate of the vehicle between the start position and end position of the curve from the start position of the curve toward an intermediate position between the start position and end position of the curve. 2. The vehicle travel line generation device according to claim 1, wherein the vehicle travel line generation device is set to increase and monotonously decrease from the intermediate position toward the end position of the curve.   3. The vehicle travel line generation device according to claim 2, wherein the target yaw rate setting means sets the minimum curvature radius position of the curve as the intermediate position.   4. The vehicle travel line generation device according to claim 2, wherein the target acceleration setting means sets the target acceleration at the intermediate position to zero.

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