JPS63603A - Guidance system for moving body - Google Patents

Abstract

PURPOSE:To calculate an optimum path extending from the present spot to a target spot, by generating a map having height as a system being capable of coping with even an object which can be got over, and providing a potential field on its map. CONSTITUTION:An image which has been inputted by an image input device 11 of a TV camera, etc., which have been installed to a robot is delivered to a device for calculating what is called a distance image for giving distance information to each picture element on the image by a method of a binocular stereoscopic vision, etc. Subsequently, by using a distance image which has been obtained from this device 12, a map which becomes a premise for calculating an optimum path is generated from a floor surface high level distribution map generating part 13. In a path calculating part 14, this map generates an optimum path extending from the present spot to a target spot by providing a potential field.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the guidance of a mobile robot using visual acuity, and in particular to a mobile robot suitable for autonomously generating a movement route using three-dimensional distance information. Concerning the body's guidance method.

[Conventional technology]

A method of calculating an optimal route based on an image (hereinafter referred to as a distance p quasi-image) in which depth position information to an object is calculated from an image input by an image input device is important in guiding a moving object. For example, it is essential for autonomous driving of cars and for exploring unknown areas such as outer space, planets, and the ocean floor.

As a route search method, for example, IEδ Proceedings, Volume 71, No. 7, 1! July 183 (Procee
d, tngs of The TEEE Vo Q,
71, Nu 7.

Hans P. Moravec () IANS P, MOIIAVEC) in “Stanford Card and CMNY Rubber 1’)” (July 1983) (“
Tha 5tanfordCart andThe C
There is a method described in a document entitled "MU Rover". This method combines a set of points that are thought to constitute an object into one object based on position information obtained from images input from a TV camera. The set of points is modeled as one object, and an ellipse surrounding the set of points is projected onto the floor.From the floor shape map where the ellipse of each object model exists, from the current point to the target point The optimal path to is found as a graph search shortest path problem.

[Problem that the invention seeks to solve]

The problem with the above-mentioned conventional technology is that even if the robot is able to climb over the modeled object, a route is always determined to avoid it, that is, the height is not taken into account.

The purpose of the present invention is to generate a map with height as a method that can deal with objects that can be climbed over, and to create a potential field on the map to find the optimal route from the current point to the target point. The purpose of this invention is to provide a guidance method for an autonomous mobile robot that performs calculations.

[Means for solving problems]

The present invention uses a distance image that provides spatial position information to generate a map (floor height distribution map) whose value is the height from the floor, and at each point on this map, a potential proportional to the height is generated. A peak with a sufficiently large potential at the current location and a valley with a sufficiently low potential at the target location are provided.

[Effect]

According to the above configuration, it is possible to calculate a route (optimal route) along which a moving object naturally moves from the current point to the target point.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the overall configuration of an autonomous mobile robot guidance device according to the present invention. An image inputted by an image input device 11 such as a TV camera installed on the robot is sent to a device 12 that calculates a so-called distance image that provides distance information for each pixel on the image using a method such as binocular stereoscopic vision. and pass it on. Next, using the distance image obtained by this device 12, the floor height distribution map generation unit 13 generates a map that is a prerequisite for calculating the optimal route. The route calculation unit 14 generates an optimal route from the current location to the target location by providing a potential field on this map.

Next, the operation of each processing section will be explained in detail.

As the information obtained by the distance image calculation unit 12, the spatial coordinate position (three-dimensional position is information) of the image for each pixel is determined with the robot's viewpoint E as the origin and the line of sight direction as shown in FIG. It is given as a coordinate system with an axis.

Using this three-dimensional position information, the floor height distribution map generation unit 12 performs the following processing. That is, this three-dimensional position information is converted into the absolute coordinate system ○W-XwYwZw (the plane on which the robot is located is assumed to be the XsYw plane) as shown in FIG. 2, and the height Z of the robot is determined.

Considering a rectangular parallelepiped (calculation area) divided by a length H2 in the line of sight direction and a length W in the horizontal direction on the
Project onto the Y w plane (the plane cut by W and 1).

This projected floor surface distribution is divided into meshes with -regular interval widths and expressed as both vertices. Considering only those points that have a sufficiently large number of points corresponding to each mesh (points corresponding to each pixel of the distance image, within the calculation area.Hereinafter, the term "points on the altitude distribution map" means this). The maximum height (Zw-component) among those points is taken as the altitude value of that mesh. This is called a floor height distribution map. An example of this floor height distribution map is shown in Figure 3. The λ-circled points in the figure indicate points that were within the calculation area (indicating the presence of an object). Next, based on this floor surface altitude distribution map, the optimal route calculating section 4 calculates the optimal route from the current point to the destination point according to the following procedure.

The optimal route calculation procedure will be explained using FIG. 4.

The path is expressed as a coordinate sequence (route point sequence) (Pfi) ρ = 0° for each distance (unit movement distance M) that the robot can move within a certain period of time with the current point as the initial value. .

(Hand M I ) Centering on the route point P, with the unit moving distance as the radius, select the candidate Pg town (k=o, ・
. . , N) is equally divided into - constant angle widths.

(Procedure ■) Potential Gi V at candidate point P□+1 (
P*+x) is calculated using the following formula.

V (P m”z) = Mar B (P m+I
l aj) + B o (P mHz) + B E (P
mHz) (Procedure III) Let the point Pm+t, which is MinV[P+t), be the next path point 1) a÷.

Here, the meanings of the symbols in (procedure I'I) are as follows.

・B (2 dishes + 1.ai) Point ai on the two-floor altitude distribution map
Consider a curved surface function B of a mountain as shown in FIG. 5(a) with (i=1..9M) as the vertex. However, the value of the vertex is point ai
, i.e., it is proportional to the altitude.

It is a numerical value.

- B a (P, +1): Consider a non-negative function BE similar to 13 above, with the current point E as the apex (its height is sufficiently large). This symbol is the function value at point Pint.

・Ba (Pa+1): A function BG as shown in Fig. 5(b) with the value of the function BE reversed and the top of the valley set as the target point G.
think of. This symbol is the function value at one point Pryu+s.

・Bo (Pant): Area other than the area of the altitude distribution map (
However, consider a function Bo as shown in FIG. 5(c) in order to avoid generating route points on the side opposite to the side where the current point E is located (open). This symbol is the function value at one point Pk+1.

By repeating the above procedure for Q from the current point E (=po) until the following termination condition is satisfied, an optimal route as shown in FIG. 6 is generated.

Termination condition: Origin P to search for the next route point Pa+1 from route point Pg
When the target point G is included in a circular area whose center is 1 and whose radius is the unit movement distance.

Alternatively, assume that the secondary route point P+1 returns to the area searched for the route point Pg (a circular area with the route point Pa-5 as the center and the radius equal to the unit movement distance).

〔Effect of the invention〕

According to the present invention, the following effects are achieved: ・Since the route search is based on a wide range of information in the form of distance images,
The reliability of the calculated optimal route is high.

・What is the height of an object that a mobile robot can climb over?

A route to overcome can be calculated.

As described above, the present guidance method is highly effective in realizing self-produced running of various types of moving objects.

[Brief explanation of the drawing]

Fig. 1 is a block configuration diagram of an apparatus for carrying out the present invention, Fig. 2 is a diagram showing a floor surface calculation area used in the process of generating a floor surface height distribution map, and Fig. 3 is a diagram showing a floor surface height distribution map. For example, Fig. 4 is a diagram showing the Irk suitable route search method, Fig. 5 is a diagram showing the potential function used in route searching, and Fig. 6 is a diagram showing the potential function used in route searching.
The figure shows one result of optimal route calculation.

Claims (1)

[Claims] 1. Convert the object position information obtained by an external sensor that can obtain distance information into an altitude distribution map projected on the floor, and obtain the optimal route from the current point to the target point from the altitude distribution map. A method for guiding a moving body, characterized in that the calculation is performed using a potential field.