JPH02115905A - Track controller for mobile vehicle - Google Patents

Abstract

PURPOSE:To realize accurate and safe travel control according to a generated track by detecting the target of a travel path photographed by a travel vehicle and relative position relation with the target, and generating a track. CONSTITUTION:A computer 3 recognizes the end of a path as the target of the travel path from an image, and generates a functional track by prescribed operation based on the relative distance of the end of the path with the travel vehicle, and computes and outputs the rotating speed NL and NR of both wheels so as to move along the track to a travel controller 4. When difference exists between the number of revolution speed NL and NR of both wheels, the travel vehicle can be steered in a desired direction. Generally speaking, since no steep change occurs in the target such as the end of the travel path or a white line, etc., the functional track is set as a circulator track. When one circular track is generated, the next circular track can be generated before the travel vehicle completes the travel of the circular track.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device that controls the running of a moving vehicle by detecting running targets such as road edges, white lines, and the like.

(Prior Art) In such conventional travel control, it is common to perform travel control along a guideway provided outside. This system recognizes the edge of the road and the position of the own vehicle, which is determined from the speed of the own army, the direction of movement of the own army, the distance traveled by the vehicle, etc., and performs feedback control based on the relationship between the edge of the road and the position of the own army. This is to control the orbit.

On the other hand, Japanese Patent Application Laid-open No. 144914/1983 discloses that when tracking a predetermined trajectory, the travel distance I2+, 12g is determined based on the target angle θ determined from this trajectory, two encoder inputs θ, and 02. Then, the vehicle travels so that the target trajectory is sandwiched between the steering directions θ and 02, and follows the trajectory on average.

(Problems to be Solved by the Invention) Of the above two conventional technologies, the former faithfully traces the shape of the road edge in order to control the running along the road edge, but it is based on information from the outside world. It is necessary to constantly calculate the vehicle's position and distance traveled, which places a heavy burden on software and hardware.

Furthermore, although the latter conventional technology does not require information about the outside world, it does require an encoder sensor or the like to know the direction, and it is also necessary to know the travel distance β11°C2.

Therefore, the present invention was proposed in order to eliminate the drawbacks of the above-mentioned conventional examples, and its purpose is to provide a trajectory control device for a moving vehicle that can easily guide a moving vehicle without the need to calculate the travel distance. This is where we propose.

(Means and operations for achieving the object) The configuration of the trajectory control device for a mobile vehicle according to the present invention for achieving the above object includes an imaging means for taking an image of the outside world, and a traveling route target and the target from the image. a detection means for detecting a relative positional relationship between the vehicle and the moving vehicle; a generating means for generating a trajectory defined by a predetermined function based on the relative positional relationship; and a traveling control of the moving vehicle in accordance with the generated trajectory. The present invention is characterized by comprising a control means.

(Embodiment) An embodiment in which the present invention is applied to a type of mobile vehicle in which two drive wheels are rotated by two motors and steering is performed by the difference in rotation will be described below with reference to the accompanying drawings.

The principle of this embodiment will be explained based on FIGS. 1A and 1B. FIG. 1A explains a type of control in which a mobile vehicle 1o is provided with steering wheels 5L and 5R each having two independent driving wheels arranged in the center. Further, the generated trajectory is also an example of a circular arc.

FIG. 3 is a diagram illustrating the configuration of the trajectory control system of the mobile vehicle 10. Reference numeral 1 denotes an imaging device attached to a moving vehicle, and the captured images are stored in a memory 2. calculator 3
recognizes the trailing edge as the target of the travel route from this image, creates a predetermined function trajectory based on the relative distance between the trailing edge and its own troops, etc., using a predetermined calculation described later, and follows this trajectory. Thus, the rotational speeds NL and NR of both wheels are calculated and output to the cruise control device 4. Rotation speed N of both wheels
If there is a difference between L and NR, the vehicle will be steered in the desired direction. In general, targets such as road edges and white lines do not change rapidly, so in this embodiment, the function trajectory is an arcuate trajectory. When one arcuate trajectory (the arcuate trajectory is defined by the radius of curvature) is created, the next arcuate trajectory is created before the vehicle has finished traveling on the created arcuate trajectory. That is, by creating a simple circular arc trajectory and controlling the steering along the trajectory in an open-loop manner, there is no need to calculate the travel distance, which reduces the burden on hardware and software.

First, the principle of an embodiment in which the steering wheel is in the center will be explained with reference to FIGS. 1A and 1B. In Figure 18, 21
is the end of the road, and the rectangle 2Q is the imaging range by the imaging device 1 of the moving vehicle 10.

In the figure, the range from point 0 to point B is the locus of the road edge detected within this range. In this trajectory control, a trajectory is created based on the relative distance between the tangled end and the own army, and in the case of FIG. 1A, point B is used as the "base point" for generating the arcuate trajectory.

Now, the traveling trajectory of the moving vehicle is generated with the following conditions attached.

(2): In other words, the condition is that the center point P of the moving vehicle remains at least a distance d from the base point B even after the circular arc trajectory has been created and the vehicle has traveled the circular arc. This distance d is determined, for example, so that the moving vehicle does not touch the tied end, and is a constant value, but an arbitrary value. In this way, the starting point and ending points P and S of the arc are determined. That is, S is the position when the center point P of the moving vehicle has finished moving along the circular arc.

If d is set in this way, when the mobile vehicle finishes moving along the circular arc, the mobile vehicle 10 will have moved by ΔX in the X direction and ΔY in the Y direction.

■: When moving on this arc, the wheels of the vehicle must face in the tangential direction. That is, the center of curvature O of the circular arc is on a line segment from point P perpendicular to the X direction. Then, in FIG. 1B, if we define 5P=42=(△X2+△Y2)l/2, we have 1, and <5OQ=ZSPT. In the above formula, β and ΔY are quantities simply determined from the relative distance between the moving vehicle and the tied end, and are obtained by calculation from the image. That is, conventionally, in order to follow a trajectory such as a clothoid curve, it is necessary to obtain a travel distance, but in this embodiment, what is required is at most ΔX and ΔY.

Radius of the arc drawn by the right wheel 5R and the left wheel 5L R R+
If r L is the tread of the wheel, then when △Y > O, r n = R + t / 2 r L = R - t / 2 When △ Y × O, r * = Rl / 2 r (, = R + t / 2. Also, when △Y=, r, : r.

becomes. The rotational speeds Nn and Nt of the left and right wheels at this time have the following relationship.

r, NR rL NL The rotational speeds NR and NL are determined depending on the processing speed of the computer 3 and how faithful the created trajectory is to the running route. Further, the position at which targets such as road edges and white lines are detected may be determined by taking into account the processing speed of the computer 3 and the fidelity of the trajectory.

Next, control when the mobile vehicle is a four-wheeled vehicle with front wheel steering will be explained based on FIG. Note that the same symbol rules as in the case of FIG. 1 are followed. In this type of front wheel, the front wheel is driven by one drive device and a differential gear. In this case, the wheelbase length W must also be taken into consideration.

In the case of this figure 2 as well, the radius of curvature of the circular arc is g= (△x
2+△Y2)l/2, it becomes. At this time, right wheel 5R, left wheel 5. The radius r R* r L of the arc drawn by
' = ((Rl/2)2+W")"28When Y<O, r R= ((R-t/2)"+W")""r
L=((R+l/2)"+W2)"" When ΔY=O, rR=rL. At this time, the rotation speeds NR1N of the left and right wheels have the following relationship.

r, N.

rL NL becomes.

Thus, according to the two embodiments described above, an arcuate trajectory is created based on at least the relative distance between the end of the road and the own troops, regardless of the method of driving the steering wheels. That is, since trajectory creation is easy, the processing amount of the system is not large, and trajectory control is easy. Although this arcuate trajectory does not exactly follow the shape of the road edge, there is no problem because it ensures that the moving vehicle is at least a distance d away from the road edge. FIG. 4 shows the relationship between the road edge as a travel target and the trajectory created in this way. In the figure, the running road edge has a sinusoidal curve shape, and the trajectory is a series of circular arcs, but the trajectory shape is close to a tangled edge shape. In order to draw a more faithful trajectory, increase the frequency of arc creation.

In the above embodiment, two conditions (■) are set to determine the circular arc, but the conditions are not limited to these, and the point is that the radius of curvature and center of the circular arc need only be determined.

Further, in the above embodiment, when the moving vehicle is a car, the trajectory is an arc when the vehicle is steered, so the trajectory is an arc. However, the functional form for drawing a trajectory is not limited to a circular arc. For example, it may be an ellipse.

Further, the method of steering the mobile vehicle is not limited to the above method, and may be one such as rotating a steering wheel.

(Effects of the Invention) As explained above, the trajectory control device for a moving vehicle according to the present invention includes an imaging means that takes an image of the outside world, and a traveling path target and a relative positional relationship between the target and the moving vehicle from the image. The vehicle is characterized by comprising: a detection means for detecting, a generation means for generating a trajectory defined by a predetermined function based on the relative positional relationship, and a control means for controlling the traveling of the mobile vehicle according to the generated trajectory. do.

Therefore, since the generated trajectory is obtained from the relative positional relationship between the target and the moving vehicle obtained from the image, there is no need to know information such as the travel distance or the absolute position of the vehicle, as in the past, so there is no need to know the control burden becomes lighter.

[Brief explanation of the drawing]

1A and 1B are diagrams for explaining the principle of one embodiment of the present invention, FIG. 2 is a diagram for explaining the principle of another embodiment, and FIG. 3 is a diagram for explaining the principle of another embodiment.
FIG. 4 is a diagram illustrating the trajectory control results according to the embodiment shown in FIG. 1 and the embodiment shown in FIG. 2. In the figure, 1...imaging device, 2...memory, 3...computer,
4... Travel control device, 51.1.5L... Steering wheel,
6L, 6R... Drive motor, 20... Imaging range, 2
1... Road edge, 22... Left wheel trajectory, 23...
- Locus of the right wheel, 24... This is the locus of point P. Old Figure Figure 1A

Claims (1)

[Claims] (1) an imaging means for taking an image of the outside world; a detection means for detecting a travel path target and a relative positional relationship between the target and the moving vehicle from the image; and a predetermined function defined based on the relative positional relationship. 1. A trajectory control device for a moving vehicle, comprising: a generating means for generating a trajectory to be generated; and a control means for controlling the traveling of the moving vehicle according to the generated trajectory.