JP2017033433A - Speed control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed control device that can suppress occurrence of undershoot when vehicles slow down.SOLUTION: A speed control device 200 controls a speed of a vehicle 100 travelling along travelling routes composed of a plurality of road sections and having a target speed set with respect to each road section. The speed control device comprises: an actual location acquisition unit 220 that acquires a real location serving an actual location of the vehicle; a real speed acquisition unit 240 that acquires a real speed serving an actual speed of the vehicle; and an acceleration/deceleration control unit 280 that controls an acceleration/deceleration speed of the vehicle so that the real speed follows the target speed set to the road section including the real location. Accompanied by movement of the real location from a first road section to a second road section, when the vehicle decelerates from a first target speed to a second target speed, the first target speed in the first road section is set so that the real speed slows down by a first order delay from the first target speed to the second target speed between a deceleration start location of the first road section and a deceleration end location thereof.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a speed control device.

  In recent years, research and development of an automatic driving system has been promoted as a solution to various problems of automobile traffic in relation to the informationization and intelligence of automobile traffic. For example, an automatic driving system is provided with a target travel route composed of a plurality of road sections and a target speed (also referred to as “regulated speed”) set in advance for each road section in advance. This is a system that performs autonomous traveling control of a vehicle including starting. The vehicle has an accelerator operation amount and a brake so that the actual speed (actual speed) of the vehicle follows the target speed set in the road section including the actual position (actual position) of the vehicle. A speed control device for controlling the operation amount is mounted.

  Patent Document 1 discloses a technique for starting automatic driving of a vehicle along a guide line laid on a traveling road surface based on permission by an automatic driving permission switch as a technique related to automatic driving.

Japanese Patent Laid-Open No. 3-142507

  By the way, in the automatic driving system, when the target speed decreases stepwise (that is, the vehicle decelerates), the actual speed of the vehicle rapidly decreases, and an undershoot occurs where the actual speed falls below the target speed. There was a problem that sometimes.

  The objective of this invention is providing the speed control apparatus which can suppress generation | occurrence | production of an undershoot when a vehicle decelerates.

The speed control device according to the present invention includes:
A speed control device configured to control a speed of a vehicle that is configured of a plurality of road sections and travels along a travel route in which a target speed is set for each road section,
An actual position acquisition unit for acquiring an actual position which is an actual position of the vehicle;
An actual speed acquisition unit for acquiring an actual speed which is an actual speed of the vehicle;
An acceleration / deceleration control unit that controls acceleration / deceleration of the vehicle so that the actual speed follows the target speed set in the road section including the actual position;
With
When the target speed decelerates from the first target speed to the second target speed as the actual position moves from the first road section to the second road section, from the deceleration start position to the end position of the first road section The target speed in the first road section is set so that the actual speed decelerates from the first target speed to the second target speed with a first-order lag.

  According to the present invention, since the target speed is not changed stepwise, but the gradient of the change in the target speed is set to be gradually reduced, the vehicle decelerates from the first target speed to the second target speed. In doing so, it is possible to suppress the occurrence of undershoot in which the actual speed falls below the target speed (second target speed).

It is a functional block diagram which shows the structure of the vehicle in this Embodiment. It is a figure explaining generation | occurrence | production of undershoot. It is a figure explaining the target speed which decelerates with a primary delay. It is a figure explaining the production | generation method of the target speed which decelerates with a primary delay. It is the figure which showed the change of the actual speed of the vehicle at the time of controlling acceleration / deceleration according to the change of the target speed which decelerates with a primary delay.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram showing a configuration of vehicle 100 in the present embodiment. In the present embodiment, vehicle 100 is a large vehicle such as a truck that is a control target in an automatic driving system and is equipped with a diesel engine (internal combustion engine). That is, the vehicle 100 includes a plurality of road sections, and a travel route (for example, an expressway) from which the vehicle 100 will travel and a target speed set in advance for each road section are provided in advance. A configuration for performing autonomous traveling control of the vehicle 100 including stopping and starting is provided.

  As shown in FIG. 1, the vehicle 100 includes a map information storage unit 120, a travel route information storage unit 140, an actual position detection unit 160, an actual speed detection unit 180, and a speed control device 200.

  The map information storage unit 120 stores map information. The map information includes road information representing roads on the map, and road information used for map display, route search, and the like, as well as facility information representing various facilities adjacent to the road. Road information includes road section information (for example, road width, road length, slope, coefficient of friction between tires and road surface, etc.) related to links (hereinafter referred to as “road sections”) expressed by dividing roads and lanes finely. And node information relating to nodes corresponding to points at both ends of each road section (including points where a plurality of roads such as intersections and branches intersect). If the road section has a curve, the road section information includes information on the radius and curvature of the curve.

  The travel route information storage unit 140 stores travel route information related to a travel route composed of a plurality of road sections. The travel route information includes target speeds set for a plurality of road sections constituting the travel route. The target speed is a speed set in advance so that when the vehicle 100 travels on a road section, the actual speed of the vehicle 100 (hereinafter referred to as “actual speed”) follows.

  The actual position detection unit 160 includes information indicating the longitude and latitude of the vehicle 100 acquired by an autonomous navigation sensor (not shown) or a GPS receiver (not shown) mounted on the vehicle 100, and a map information storage unit 120. The actual position (current position) that is the actual position of the vehicle 100 on the map is detected based on the map information stored in the map. Then, the actual position detection unit 160 outputs the detected actual position to the speed control device 200.

  The actual speed detector 180 is a vehicle speed sensor, for example, and detects the actual speed (traveling speed) of the vehicle 100. Then, the actual speed detection unit 180 outputs the detected actual speed to the speed control device 200.

  The speed control device 200 controls the speed of the vehicle 100 that travels along the travel route indicated by the travel route information stored in the travel route information storage unit 140. As shown in FIG. 1, the speed control device 200 includes an actual position acquisition unit 220, an actual speed acquisition unit 240, a target acceleration / deceleration calculation unit 260, and an acceleration / deceleration control unit 280. The target acceleration / deceleration calculation unit 260 and the acceleration / deceleration control unit 280 correspond to the “acceleration / deceleration control unit” of the present invention.

  The actual position acquisition unit 220 acquires the actual position output from the actual position detection unit 160 and outputs it to the target acceleration / deceleration calculation unit 260.

  The actual speed acquisition unit 240 acquires the actual speed output from the actual speed detection unit 180 and outputs it to the target acceleration / deceleration calculation unit 260.

  The target acceleration / deceleration calculation unit 260 is output from the actual position acquisition unit 220 based on the map information stored in the map information storage unit 120 and the travel route information stored in the travel route information storage unit 140. A target acceleration / deceleration for causing the actual speed output from the actual speed acquisition unit 240 to follow the target speed set in the road section including the actual position is calculated.

  Specifically, the target acceleration / deceleration calculation unit 260 calculates the target acceleration / deceleration by a PI feedback control method for the speed deviation between the target speed and the actual speed.

  The acceleration / deceleration control unit 280 is output from the target acceleration / deceleration calculation unit 260 when the target acceleration / deceleration output from the target acceleration / deceleration calculation unit 260 is a positive value (that is, when the vehicle 100 needs to be accelerated). An accelerator opening (accelerator operation amount of the vehicle 100) is determined with reference to the accelerator map according to the target acceleration / deceleration, and an electronic vehicle control device (ECM) that performs engine control according to the determined accelerator opening is provided. Control. When the target acceleration / deceleration output from the target acceleration / deceleration calculation unit 260 is a positive value, the acceleration / deceleration control unit 280 does not control the accelerator opening, but controls the fuel injection amount, for example. Also good.

  In addition, when the target acceleration / deceleration output from the target acceleration / deceleration calculation unit 260 is a negative value (that is, when the vehicle 100 needs to be decelerated), the acceleration / deceleration control unit 280 determines from the target acceleration / deceleration calculation unit 260. An EBS (electronically controlled brake system) that determines a braking force (a brake operation amount of the vehicle 100) with reference to a braking force gain according to the output target acceleration / deceleration, and generates a braking force according to the determined braking force To control. In addition, when the target acceleration / deceleration output from the target acceleration / deceleration calculation unit 260 is a negative value, control other than the brake operation amount of the vehicle 100 may be controlled.

  Incidentally, when the vehicle 100 travels along the travel route, if the target speed decreases stepwise (that is, the vehicle 100 decelerates), the actual speed of the vehicle 100 rapidly decreases, and the actual speed becomes the target speed. In some cases, undershoot may occur. FIG. 2 is a diagram for explaining the occurrence of undershoot. In FIG. 2, the dotted line L1 indicates that the target speed is changed from the first target speed (for example, 80 [km / h]) to the second target speed (for example, 80 km / h) as the actual position moves from the first road section to the second road section. , 60 [km / h]). A solid line L2 indicates a change in the actual speed of the vehicle 100 when the acceleration / deceleration is controlled according to the change in the target speed indicated by the dotted line L1. As shown in FIG. 2, when the target speed decreases stepwise from the first target speed to the second target speed, an undershoot occurs in which the actual speed of the vehicle 100 falls below the target speed (second target speed). Further, after the actual position moves from the first road section to the second road section, a section where the actual speed of the vehicle 100 exceeds the second target speed (between position P1 and position P2 in FIG. 2) occurs. End up.

Therefore, in the present embodiment, in the travel route information stored in the travel route information storage unit 140, the vehicle between the deceleration start position P3 and the end position P4 of the first road section as shown by the solid line L3 in FIG. The target speed in the first road section is set in advance so that the actual speed of 100 decelerates from the first target speed to the second target speed with a primary delay. That is, the target speed is not changed stepwise, but is set so that the slope of the change in the target speed gradually decreases. Specifically, the target speed in the first road section is set so as to gradually change with the time function shown in the following equation (1).
Target speed = first target speed + (second target speed−first target speed) × (1-exp (−t / T)) (1)
Here, t is an elapsed time since the start of deceleration, and T is a time constant of a first-order lag (standard response speed).

The first-order delay time constant T is calculated according to the difference between the first target speed and the second target speed. In the present embodiment, the first-order delay time constant T is obtained by dividing the value obtained by subtracting the second target speed from the first target speed by the maximum deceleration of the vehicle 100 as shown in the following equation (2). Is calculated by The maximum deceleration of the vehicle 100 is, for example, 1.0 [m / s ² ], and is uniquely determined by the weight, speed, gear stage, or the like of the vehicle 100.
Primary delay time constant T = (first target speed−second target speed) / maximum deceleration of vehicle 100 (2)

  As described above, the target speed of the first-order lag is generated by the above equation (1), but the deceleration time (t) required to decelerate to the second target speed even if it is attempted to decelerate to the second target speed. Is infinite and cannot be completely decelerated to the second target speed. Therefore, in the present embodiment, a first-order lag target speed is generated as follows. That is, as shown in FIG. 4, a curve of the target speed of the first-order lag that decelerates to 95 [%] (hereinafter referred to as “ratio”) of the speed change width (ΔV) (dashed line L3 ′ in FIG. 4) Is generated. Next, the generated curve is multiplied by a coefficient (1 / 0.95 when the ratio is 95 [%]) to extend the curve to the second target speed (see the solid line L3 in FIG. 4). The ratio may be adjusted, for example, in the range of 65 to 99 [%] according to the difference in the deceleration capability of the vehicle.

The deceleration distance Lpre from the deceleration start position P3 to the end position P4 is the difference between the second target speed and the first target speed (speed change width ΔV = second target speed−first target speed) and the first-order delay. It is calculated based on the constant T. In the present embodiment, the deceleration distance Lpre is calculated by the following equation (3).
Deceleration distance Lpre = {first target speed + ΔV × (1−exp (−t / T)}) obtained by time integration with a deceleration time up to 95% of the absolute value of the speed change width (3)

  FIG. 5 is a diagram showing a change in the actual speed of the vehicle 100 indicated by a two-dot chain line L4 when the acceleration / deceleration is controlled according to the change in the target speed that decelerates with a first-order delay as shown by the solid line L3. As shown in FIG. 5, it can be seen that there is almost no undershoot in which the actual speed of the vehicle 100 falls below the target speed (second target speed). In addition, as a result of starting deceleration before the end position of the first road section, there is a section where the actual speed of the vehicle 100 exceeds the second target speed after the actual position moves from the first road section to the second road section. You can see that they are not.

  As described above in detail, in the present embodiment, the speed control device 200 includes a plurality of road sections, and the speed of the vehicle 100 that travels along a travel route in which a target speed is set for each road section. To control. The speed control device 200 includes an actual position acquisition unit 220 that acquires an actual position that is an actual position of the vehicle 100, an actual speed acquisition unit 240 that acquires an actual speed that is an actual speed of the vehicle 100, and an actual position. An acceleration / deceleration control unit (target acceleration / deceleration calculation unit 260, acceleration / deceleration control unit 280) that controls the acceleration / deceleration of the vehicle 100 is provided so that the actual speed follows the target speed set in the road section. When the target speed decelerates from the first target speed to the second target speed as the actual position moves from the first road section to the second road section, between the deceleration start position and the end position of the first road section The target speed in the first road section is set so that the actual speed decelerates from the first target speed to the second target speed with a primary delay.

  According to the present embodiment configured as described above, the target speed is not changed stepwise, but the gradient of the change in the target speed is set to be gradually reduced. When decelerating from the speed to the second target speed, it is possible to suppress the occurrence of undershoot in which the actual speed falls below the target speed (second target speed).

  In the above embodiment, when the target speed decelerates from the first target speed to the second target speed as the actual position moves from the first road section to the second road section, deceleration of the first road section starts. The example in which the target speed in the first road section is set in advance so that the actual speed decelerates from the first target speed to the second target speed with a primary delay between the position and the end position has been described. The invention is not limited to this. For example, when the vehicle 100 travels along the travel route, the timing at which the target speed approaches the road section (second road section) where the target speed decelerates from the first target speed to the second target speed (for example, the second road section). The timing at which the vehicle 100 arrives at a position 500 [m] before the start position) so that the actual speed of the vehicle 100 decelerates from the first target speed to the second target speed with a primary delay. The target speed may be changed.

  In addition, each of the above-described embodiments is merely an example of actualization in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. That is, the present invention can be implemented in various forms without departing from the gist or the main features thereof.

  The present invention is useful as a speed control device that can suppress the occurrence of undershoot when the vehicle decelerates.

DESCRIPTION OF SYMBOLS 100 Vehicle 120 Map information storage part 140 Travel route information storage part 160 Real position detection part 180 Real speed detection part 200 Speed control device 220 Real position acquisition part 240 Real speed acquisition part 260 Target acceleration / deceleration calculation part 280 Acceleration / deceleration control part

Claims (3)

A speed control device configured to control a speed of a vehicle that is configured of a plurality of road sections and travels along a travel route in which a target speed is set for each road section,
An actual position acquisition unit for acquiring an actual position which is an actual position of the vehicle;
An actual speed acquisition unit for acquiring an actual speed which is an actual speed of the vehicle;
An acceleration / deceleration control unit that controls acceleration / deceleration of the vehicle so that the actual speed follows the target speed set in the road section including the actual position;
With
When the target speed decelerates from the first target speed to the second target speed as the actual position moves from the first road section to the second road section, from the deceleration start position to the end position of the first road section The target speed in the first road section is set so that the actual speed is decelerated with a first order delay from the first target speed to the second target speed during
Speed control device. The deceleration distance from the deceleration start position to the end position is calculated based on the difference between the second target speed and the first target speed and the time constant of the first-order lag.
The speed control apparatus according to claim 1. The time constant of the first-order lag is calculated according to the difference between the first target speed and the second target speed.
The speed control apparatus according to claim 1 or 2.

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