JP2017100654A - Traveling control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology which makes a vehicle travel at a proper target speed when the vehicle travels at a curve having a gradient within a range of speed limit.SOLUTION: In S400, a traveling control device acquires a speed limit of a road on which an own vehicle travels, and in S404, sets an upper speed limit at which the own vehicle does not slide when traveling at a curve on the basis of a friction coefficient between the own vehicle and a road face on which the own vehicle travels. In S406, when the own vehicle travels at the curve, the traveling control device sets a lower speed as a proper speed by comparing the speed limit and the upper speed limit, and in S408, when the own vehicle travels on a linear road, sets the speed limit as the proper speed. In S414, when the own vehicle travels at a front part of an uphill, or a downhill, the traveling control device sets a correction amount with respect to the proper speed from a gradient of a slope and the proper speed, and in S416, sets a target speed by correcting the proper speed by the correction amount. In S420, the travel control device makes the own vehicle travel at the target speed.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a technique for controlling the vehicle speed of a host vehicle.

  Various technologies for controlling the driving of a vehicle, from those that assist the driver's driving operation in terms of driving force, braking force, steering angle, etc., to those that automatically perform all driving control on behalf of the driver The technology is known.

  In the technique disclosed in Patent Document 1, a point at which the speed limit defined by a road sign or the like is switched low is detected, and the switched speed limit is set as a target speed. If the current vehicle speed exceeds the set target speed, the vehicle speed is reduced to the target speed.

  Further, in the technique disclosed in Patent Document 1, a target speed for entering a curve is set using a smaller one of a preset allowable lateral acceleration or a road surface friction coefficient and a turning radius of the own vehicle. doing. If the current vehicle speed exceeds the target speed, the vehicle speed is reduced to the target speed.

  In addition to the speed limit and the curve, if you approach the top of the uphill and it is difficult to see the other side of the top, or if you drive down the slope and the vehicle speed increases, reduce the vehicle speed so as not to disturb the driver. It is possible.

JP 2009-6828 A

  If the road is a curve and you drive on the part of the top of the uphill or downhill, the speed limit, the target speed for driving the curve, and the target speed set based on the road gradient It is conceivable that the speeds are acquired or calculated independently, and the slowest speed among the three speeds is set as the target speed.

  Here, when setting the target speed based on the road gradient, the correction amount for the current vehicle speed is calculated based on the current vehicle speed and the road gradient, and the target speed is set by correcting the current vehicle speed. It is possible to set.

  However, if the current vehicle speed is so slow that correction is not necessary and the correction amount for the current vehicle speed calculated based on the current vehicle speed and the road gradient is 0, the current vehicle speed is based on the current vehicle speed and the road gradient. The target speed to be set is the current vehicle speed.

  When the current vehicle speed is slower than the vehicle speed set based on the speed limit and the target speed when traveling on the curve, the current vehicle speed is set as the target speed. The current vehicle speed is set as the target speed even when the vehicle is traveling at a higher vehicle speed than the current vehicle speed, as long as the road is currently traveling.

  In this way, the three speeds of the speed limit, the target speed when driving on the curve, and the target speed set based on the road gradient are independently acquired or calculated, and the three speeds are obtained. If the slowest speed is set as the target speed, an appropriate target speed may not be set.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for traveling a vehicle at an appropriate target speed when traveling on a sloped curve within a speed limit range.

  The travel control device (10) of the present invention includes a speed limit unit (22, S400), an upper limit speed unit (24, S404), an appropriate speed unit (26, S406, S408), and a gradient acquisition unit (28, S410). ), A target speed unit (30, S416, S418), and a vehicle speed control unit (40, S420).

  The speed limit part acquires the speed limit of the road (200) on which the vehicle (100) is traveling. The upper limit speed unit sets an upper limit speed at which the vehicle does not skid when the vehicle travels a curve, based on a friction coefficient between the vehicle and the road surface on which the vehicle travels.

  When the vehicle travels on a curve, the appropriate speed section compares the speed limit acquired by the speed limit section with the upper limit speed set by the upper speed limit section, and sets the slower speed as the appropriate speed. When traveling, set the speed limit as the appropriate speed. The gradient acquisition unit acquires an uphill or downhill gradient.

  The target speed unit sets the correction amount for the appropriate speed from the gradient acquired by the gradient acquisition unit and the appropriate speed set by the appropriate speed unit when the vehicle travels in front of the top of the uphill or downhill, The target speed is set by correcting the appropriate speed according to the correction amount. If the vehicle does not travel on the front part of the top of the uphill and the downhill, the appropriate speed is set as the target speed. The vehicle speed control unit causes the host vehicle to travel at the target speed.

  According to this configuration, the centrifugal force is greater than the frictional force within the speed limit range and the vehicle is prevented from skidding sideways with respect to an appropriate speed, at least one of the front part of the uphill and the downhill. The correction amount is set from the road gradient and the appropriate speed. Thereby, if there is no need to correct the appropriate speed, the appropriate speed is set as the target speed, and if there is a need for correction, the correction amount is decelerated with respect to the appropriate speed and the target speed is set.

  Therefore, the vehicle is prevented from slipping due to the centrifugal force being greater than the frictional force within the speed limit range, and the driver is uncomfortable when traveling on at least one of the top of the uphill and the downhill. An appropriate target speed can be set without giving

  Note that the reference numerals in parentheses described in this column and in the claims indicate the correspondence with the specific means described in the embodiment described later as one aspect, and the technical scope of the present invention. It is not limited.

The block diagram which shows the traveling control system by this embodiment. The schematic diagram which shows the centrifugal force and frictional force which act on the own vehicle. The schematic diagram which shows the own vehicle which drive | works the front part of the top of a slope. The flowchart which shows a traveling control process.

Embodiments to which the present invention is applied will be described below with reference to the drawings.
[1. Constitution]
A travel control system 2 shown in FIG. 1 includes a travel control device 10, a camera 50, an acceleration sensor 52, a steering sensor 54, a navigation device 56, a vehicle speed sensor 58, a powertrain system 60, and a brake system 62. It has.

  The travel control device 10 includes a computer including a CPU, RAM, ROM, flash memory, I / O interface, and the like, and includes a vehicle speed setting unit 20 and a vehicle speed control unit 40. The traveling control apparatus 10 executes a program recorded in a non-transitional tangible recording medium such as a ROM or a flash memory, thereby executing a traveling control function corresponding to the program.

The vehicle speed setting unit 20 includes a speed limit unit 22, an upper limit speed unit 24, an appropriate speed unit 26, a gradient acquisition unit 28, and a target speed unit 30.
As shown in FIG. 2, the speed limit unit 22 indicates the speed limit of the road 200 on which the vehicle 100 travels, image data of the road sign 110 captured by the camera 50, map information of the map DB provided in the navigation device 56, and the like. Get from.

  In the upper limit speed unit 24, the road 200 on which the host vehicle 100 travels is a curve based on image data representing the road shape ahead of the host vehicle 100 captured by the camera 50, map information in the map DB provided in the navigation device 56, or the like. Whether it is a curve or not, obtains the radius of curvature.

Furthermore, the upper limit speed unit 24 sets an upper limit speed that suppresses skidding to the outside of the curve when the host vehicle 100 travels on the curve. Details of the setting of the upper limit speed will be described later.
The appropriate speed unit 26 sets the slower speed of the speed limit acquired by the speed limit unit 22 and the upper speed limit set by the upper limit speed unit 24 as the appropriate speed.

  The gradient acquisition unit 28 acquires the gradient of the road 200 on which the host vehicle 100 travels from the map information of the map DB provided in the navigation device 56. Although FIG. 3 shows an uphill road 200, the road 200 may be downhill.

  The target speed unit 30 sets a correction amount for correcting the appropriate speed based on the gradient of the road 200 and the appropriate speed when the vehicle 100 travels in front of the top 220 of the uphill or downhill. As the slope of the uphill and downhill becomes steeper, the correction amount for the appropriate speed may be increased. Then, the target speed unit 30 corrects the appropriate speed with the set correction amount and sets it as the target speed.

  Note that the range represented by the front portion of the uphill vertex 220 is a range in which the driver feels uneasy because the vehicle 100 approaches the vertex 220 and the other side of the vertex 220 is difficult to see. This range is preset according to the gradient by a test drive experiment or the like. As the slope of the uphill becomes steeper, the range in front of the vertex 220 may be lengthened. Also, the driver may set the range of the front portion as appropriate.

  Further, since the driver's field of view changes depending on the vehicle height, the target speed unit 30 may set the range of the front portion according to the vehicle height. The driver's field of view increases as the vehicle height increases, and the driver's field of view decreases as the vehicle height decreases. Therefore, the target speed unit 30 shortens the range of the front portion of the apex 220 as the vehicle height increases, and lengthens the range of the front portion of the apex 220 as the vehicle height decreases.

  Since the camera 50 and other sensors cannot detect the other side of the vertex 220, the detection range is narrowed. Therefore, a correction amount for correcting the appropriate speed is set in accordance with the slope of the uphill in the portion before the vertex 220, the appropriate speed is decelerated and corrected, and before reaching the vertex 220 of the uphill, the camera 50 and other sensors It is desirable to increase the number of detections.

  Thus, it is desirable that the correction amount for the appropriate speed is set based on the slope of the slope and the appropriate speed, and based on the vehicle height and the detection performance of the camera 50 and other sensors.

The vehicle speed control unit 40 controls the powertrain system 60 and the brake system 62 so that the vehicle speed of the host vehicle 100 becomes the target speed set by the target speed unit 30.
The camera 50 is attached, for example, near the center of the window shield mirror in the passenger compartment of the host vehicle, and images the front of the host vehicle 100 and outputs image data.

The acceleration sensor 52 detects lateral acceleration applied to the host vehicle 100. The steering sensor 54 detects the steering angle of the host vehicle 100.
The navigation device 56 guides the route to the destination based on the current position of the own vehicle 100 and the destination of the own vehicle 100 input from the touch panel or the like. The navigation device 56 receives a positioning signal from a positioning satellite such as a GPS satellite, and maps the vehicle position based on the map information stored in the map DB. The map information stored in the map DB stores a road type, a road speed limit, a road curvature radius, a road gradient, and the like.

  The navigation device 56 uses the map information in the map DB and the vehicle speed detected by the navigation device 56 receiving a positioning signal from a positioning satellite such as a GPS satellite and the speed limit of the road 200 on which the vehicle 100 is traveling. If the road is a curve, the radius of curvature is obtained, and if the road is a slope, the gradient is obtained.

The vehicle speed sensor 58 detects the vehicle speed of the host vehicle 100.
In the case where an internal combustion engine is mounted as a drive source, the powertrain system 60 controls the opening degree of the throttle device and the fuel injection amount according to the drive output commanded from the vehicle speed control unit 40, and uses the motor as the drive source. If it is installed, the power supplied to the motor is controlled.

  The brake system 62 controls an actuator provided in the hydraulic circuit of the hydraulic brake according to the braking force commanded from the vehicle speed control unit 40. When the host vehicle has a motor as a driving source, the brake system 62 controls the power supplied to the motor according to the braking force commanded by the vehicle speed control unit 40 and generates the braking force by the regenerative braking. May be.

[2. processing]
Hereinafter, the traveling control process executed by the traveling control device 10 will be described based on the flowchart of FIG. The flowchart of FIG. 4 is always executed at predetermined time intervals.

  In S400, the speed limit unit 22 determines the own vehicle 100 based on at least one of the image data of the road sign 110 captured by the camera 50 and the map information stored in the map DB provided in the navigation device 56. The speed limit of the road 200 on which the vehicle travels is acquired.

In S402, the upper limit speed unit 24 acquires the curvature radius of the road 200 on which the vehicle 100 is traveling, and determines whether the road 200 is a curve based on the acquired curvature radius.
For example, the upper limit speed unit 24, based on the image data captured by the camera 50, as shown in FIG. 2, the left and right white lines 210 and 212 that define the travel path on which the host vehicle 100 travels, for example, the white line and the road surface. It detects based on the brightness | luminance difference of. Then, the upper limit speed unit 24 calculates the curvature of the road 200 based on the detected coordinates of the left and right white lines 210 and 212, for example.

  Further, the upper limit speed unit 24 may calculate the curvature radius by the following equation (1) based on the lateral acceleration detected by the acceleration sensor 52 and the vehicle speed detected by the vehicle speed sensor 28. In equation (1), the lateral acceleration is α, the vehicle speed is v, and the radius of curvature is r.

r = v ² / α (1)
Further, the upper limit speed unit 24 may acquire the radius of curvature of the traveling road 200 from the map information stored in the map DB and the vehicle position. Further, the curvature radius of the traveling road 200 may be calculated based on the steering angle detected by the steering sensor 54.

  When the determination in S402 is Yes and the road is a curve, in S404, the upper limit speed unit 24 calculates an upper limit speed for suppressing the own vehicle 100 from skidding outside the curve when traveling on the curve. In order for the own vehicle 100 not to skid, the friction force Ft between the tire and the road surface received by the own vehicle 100 in a direction opposite to the centrifugal force Fv needs to be larger than the centrifugal force Fv received by the own vehicle 100.

  Here, when gravitational acceleration is g, the mass of the vehicle 100 is M, the vehicle speed of the vehicle 100 is v, the radius of curvature of the curve is r, and the friction coefficient between the vehicle 100 and the road surface on which the vehicle 100 travels is μ. The centrifugal force Fv is expressed by the following equation (2), and the frictional force Ft is expressed by the following equation (3). The friction coefficient μ is set on the assumption that the vehicle 100 is traveling on a wet road surface in order to suppress the side slip of the host vehicle 100 as much as possible.

Fv = Mv ² / r (2)
Ft = μMg (3)
And from the relationship of following Formula (4), if it is the speed range which satisfies following Formula (5), it can suppress that the own vehicle 100 slips to the outer side of a curve.

Fv = Mv ² / r <Ft = μMg (4)
v ² / r <μg (5)
In S404, the upper limit speed unit 24 sets the amount of deceleration to be appropriately set based on the detection error of the sensor, etc., the road surface condition, and the vehicle speed of the host vehicle 100 within the range satisfying the equation (5). The upper limit value subtracted from the speed v calculated as an equation is set as the upper limit speed of the vehicle 100.

In S406, the appropriate speed unit 26 compares the speed limit acquired in S400 with the upper limit speed set in S404, sets the slower speed as the appropriate speed, and proceeds to S410.
If the determination in S402 is No and the road is a straight line, in S408, the appropriate speed unit 26 sets the speed limit acquired in S400 as the appropriate speed, and the process proceeds to S410.

In S410, the gradient acquisition unit 28 acquires the gradient of the road on which the vehicle 100 is traveling from the map information stored in the map DB included in the navigation device 56.
In S412, the target speed unit 30 determines whether or not the vehicle 100 is traveling on a part before the top 220 of the uphill or on the downhill. This determination is made based on the current position of the vehicle 100 acquired from the navigation device 56 and the gradient of the road on which the vehicle 100 travels.

  If the determination in S412 is Yes and the vehicle 100 is traveling on either the front part of the top 220 of the uphill or the downhill, the target speed unit 30 in S414, the road gradient acquired in S410, Based on whether the slope is an uphill or a downhill and the appropriate speed set in S406 or S408, a correction amount for correcting the appropriate speed is acquired using a map or the like. In S416, the target speed unit 30 sets the target speed by correcting the appropriate speed with the correction amount, and the process proceeds to S420.

  If the determination in S412 is No, and the vehicle 100 is not traveling on either the front part of the uphill apex 220 or the downhill, the target speed unit 30 in S418 determines the appropriate speed set in S406 or S408. The target speed is set, and the process proceeds to S420.

  In S420, the vehicle speed control unit 40 determines whether the actual vehicle speed is the target speed based on the difference between the target speed set in S416 or S418 and the actual vehicle speed detected by the vehicle speed sensor 58. The control amount of the driving force and the braking force is commanded to the system 62.

[3. effect]
In the embodiment described above, the following effects can be obtained.
(1) When setting the target speed, first, an appropriate speed is set based on the speed limit and the upper limit speed that suppresses the vehicle from skidding to the outside of the curve when traveling on the curve. Thereby, the appropriate speed which suppresses that the centrifugal force becomes larger than the frictional force and the vehicle slips within the speed limit range can be set.

  And since the amount of correction for the appropriate speed is set based on the road slope and the appropriate speed at the top of the uphill and at least one of the downhill, the vehicle slips within the speed limit range when driving on a curve. In addition, it is possible to set an appropriate target speed when traveling on at least one of the portion before the top of the uphill and the downhill.

  (2) Since the road beyond the apex is difficult to see in front of the top of the uphill slope, the centrifugal force is larger than the frictional force within the speed limit range, and it is at an appropriate speed that suppresses the vehicle from skidding. Even so, the driver may feel anxious just before the top of the uphill.

  Also, depending on the slope of the downhill, the driver may feel uneasy even if the centrifugal force is greater than the frictional force within the speed limit range and the vehicle is at an appropriate speed that prevents the vehicle from skidding.

Therefore, by correcting the appropriate speed based on the appropriate speed and the slope, it is possible to reduce the anxiety that the driver feels when traveling on the part before the top of the uphill and on the downhill.
(3) By correcting and decelerating the appropriate speed based on the appropriate speed and gradient at the portion before the top of the uphill, for example, the number of times that the camera 50 takes an image before reaching the top of the uphill is increased. . Thereby, based on the image data which the camera 50 images, the frequency | count of detection of the road environment and driving environment ahead of the own vehicle increases.

[4. Other Embodiments]
(1) The friction coefficient used for calculating the frictional force acting in the direction opposite to the centrifugal force may be set to be appropriately variable according to the road surface condition. For example, the friction coefficient may be set based on weather information acquired by communication from the outside, or the driver may input the friction coefficient to the travel control device 10 based on the weather. Further, a friction coefficient for calculating a friction force acting on the opposite side to the centrifugal force may be set based on a slip ratio calculated from the vehicle speed and the tire rotation speed.

  (2) In the above embodiment, the function executed by the traveling control device 10 is realized by software by executing a program recorded in a non-transitional tangible recording medium such as a ROM or a flash memory. On the other hand, a part or all of the functions executed by the traveling control device 10 may be configured by hardware using one or a plurality of ICs.

  When some or all of the functions of the traveling control device 10 are configured by electronic circuits that are hardware, it can be provided by digital circuits including a large number of logic circuits, or analog circuits.

  (3) The functions of one constituent element in the above embodiment may be distributed as a plurality of constituent elements, or the functions of a plurality of constituent elements may be integrated into one constituent element. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified only by the wording described in the claims are embodiments of the present invention.

  (4) In addition to the travel control device 10 described above, a travel control system 2 including the travel control device 10 as a constituent element, a travel control program for causing the computer to function as the travel control device 10, and the travel control program are recorded. The present invention can also be realized in various forms such as a recording medium and a travel control method.

2: traveling control system, 10: traveling control device, 20: vehicle speed setting section, 22: speed limit section, 24: upper limit speed section, 26: appropriate speed section, 28: gradient acquisition section, 40: vehicle speed control section, 100: Own car, 200: road, 220: apex

Claims (4)

A speed limit unit (22, S400) for acquiring a speed limit of the road (200) on which the host vehicle (100) is traveling;
Based on the coefficient of friction between the host vehicle and the road surface on which the host vehicle travels, an upper limit speed section (24, S404) that sets an upper limit speed at which the host vehicle does not skid when traveling on a curve;
When the vehicle travels on the curve, the speed limit obtained by the speed limit unit is compared with the upper limit speed set by the upper limit speed unit, and the slower speed is set as an appropriate speed. When traveling on a straight road, an appropriate speed part (26, S406, S408) for setting the speed limit as the appropriate speed;
A gradient acquisition unit (28, S410) for acquiring an uphill or downhill gradient;
When the vehicle travels in front of the top of the uphill or the downhill, the correction amount for the appropriate speed is calculated from the gradient acquired by the gradient acquisition unit and the appropriate speed set by the appropriate speed unit. Set the target speed by correcting the appropriate speed with the correction amount, and set the appropriate speed as the target speed when the vehicle does not travel on the top of the uphill and the downhill. A target speed section (30, S416, S418);
A vehicle speed control unit (40, S420) for driving the host vehicle at the target speed set by the target speed unit;
A travel control device (10) comprising: The travel control device according to claim 1,
The upper limit speed unit acquires the friction coefficient based on a road surface state on which the host vehicle travels.
Travel control device. In the traveling control device according to claim 1 or 2,
The upper limit speed unit sets the upper limit speed so that a frictional force received by the host vehicle in a direction opposite to the centrifugal force is greater than a centrifugal force received by the host vehicle when traveling on the curve.
Travel control device. In the travel control device according to any one of claims 1 to 3,
The target speed unit sets the correction amount from the gradient, the appropriate speed, and the vehicle height of the host vehicle.
Travel control device.

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