JPH0769167B2 - Shape discriminator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a shape determination device for determining the shape of an object.

(B) Conventional technology In mobile work vehicles such as cleaning robots, it is necessary to work efficiently while avoiding obstacles. Therefore, various methods have been proposed for shape recognition of objects such as obstacles and walls. In most of the conventional techniques, an ultrasonic range finder is spatially scanned to sample a large number of distance measurement points. As such a conventional method of recognizing a target object, as shown in FIG. 5, an ultrasonic oscillator (T) is provided at the center of the front part of the work vehicle, and ultrasonic receivers (R) are provided on both sides of the ultrasonic oscillator (T).
There are ones arranged one by one, and it is possible to measure six ultrasonic wave propagation times at the same time by emitting one ultrasonic wave, and the shortest distance between the ultrasonic oscillator (T) and the object can be measured by the triangulation method.
It can be calculated by 6C ₂ = 15 calculation methods, and reliability can be improved.

C) Problems to be solved by the invention By the way, in such a recognition method, if the shape of the object in front of the work vehicle is different as shown in FIGS. Since the patterns are different, the method of calculating the distance is different. For this reason, it is necessary to detect the shape of the object and accurately measure the distance to the object according to the shape.

D) Means for solving the problems The present invention has been made in view of the above points,
A plurality of ultrasonic oscillators arranged on the same plane, a plurality of ultrasonic detectors provided between these ultrasonic oscillators, and means for outputting ultrasonic waves from the plurality of ultrasonic oscillators at different times. And means for discriminating the shape of the target object based on the detection pattern when the ultrasonic waves emitted from the plurality of ultrasonic oscillators are detected by the ultrasonic detectors, respectively.

G) Since the shape of an object such as a working wall is recognized, the distance to the object in front can be calculated appropriately and accurately even if the shape changes.

F) Example FIG. ₁ shows a block diagram of an example of the shape discriminating apparatus of the present invention, in which (T ₁ ) and (T ₂ ) are the _first blocks arranged at both front ends of the movable work vehicle (1). , The second ultrasonic oscillator, (P ₁ )
(P ₂ ) is a drive circuit for driving this ultrasonic oscillator (T ₁ ) (T ₂ ), and the switch (Ps ₁ ) (Ps ₂ ) is passed from the control circuit (3) through the interface (2). By turning on alternately, a reset signal is sent to the drive circuits (P ₁ ) (P ₂ ) and ultrasonic waves are alternately emitted from the ultrasonic oscillators (T ₁ ) (T ₂ ). (R ₁ ) (R ₂ ) ... (Rn) is the ultrasonic oscillator (T ₁ )
Ultrasonic detectors equally spaced between (T ₂ ),
Ultrasonic wave receiving circuit (V ₁ ) (V ₂ )… (V
The ultrasonic reception signal is obtained by n). (C ₁ ),
(C ₂ ), (C ₃ ) ... (Cn) are propagation time counting circuits
The internal digital counter is counted until the ultrasonic reception signal is obtained after receiving the t signal. That is, this data Data1 corresponds to the propagation time of ultrasonic waves and is taken into the control circuit (3) through the I / O interface 2. Further, all the ultrasonic wave reception signals are input to the signal comparison circuit (S), and the signal comparison circuit S outputs the device number of the ultrasonic wave detector received first as data to the computer. This is Da
It is indicated by ta2.

FIGS. 2 and 3 show a method of discriminating the shape of an object when using such an apparatus. In the present invention, an object having an edge as shown in FIG. 2 and FIG. Its main purpose is to distinguish between flat objects such as those shown in.
In FIG. 2, the ultrasonic wave emitted from the ultrasonic oscillator (T ₁ ) is reflected by the edge Q of the target object and reaches the ultrasonic wave detectors (R ₁ ) (R ₂ ) ... (R ₆ ). In this example, _six ultrasonic detectors (R ₁ ) (R ₂ ) ... (R ₆ ) are arranged on the straight line connecting the ultrasonic oscillators (T ₁ ) and (T ₂ ). The propagation path of the ultrasonic wave from the ultrasonic oscillator (T ₁ ) is S
Shown by ₁₁ , S ₁₂ , S ₁₃ , S ₁₄ , S ₁₅ , and S ₁₆ . Similarly, the ultrasonic waves emitted from the ultrasonic oscillator (T ₂ ) are S ₂₁ , S ₂₂ , S ₂₃ ,
Propagate with S ₂₄ , S ₂₅ , and S _26, and reach the ultrasonic detector. Given that the ultrasonic wave propagates ideally, the reflected wave arrives fastest from the edge Q perpendicularly to the ultrasonic detector (R ₁ ) (R ₂ )… (R ₆ ) row in front of the work vehicle. It is the point where it was lowered. Therefore, in this case, no matter which of the ultrasonic transmitters (T ₁ ) and (T ₂ ) emits ultrasonic waves, the ultrasonic detector (R ₄ ) or (R ₅ ) first detects ultrasonic waves. , The device number is selected by the signal comparison circuit (S).

On the other hand, when ultrasonic waves are emitted from the ultrasonic oscillator (T ₁ ) to an object whose surface is flat as shown in FIG. 3, S ₁₁ , S ₁₂ , S ₁₃ ,
It is predicted to propagate with S ₁₄ , S ₁₅ , and S ₁₆ . This is regarded as the intersection of the ultrasonic generator (T ₁₎ and the point surfaces subject to object plane is Q ₁ Q ₁ and each of the detector connecting it straight and the object surface is reflected point . So the earliest,
The reflected wave is considered to be detected by the detector closest to the foot of the perpendicular line from Q ₁ to the front of the work vehicle. Similarly, the ultrasonic waves emitted from the ultrasonic oscillator (T ₂ ) are S ₂₁ , S ₂₂ , S ₂₃ , S ₂₄ ,
Ultrasonic oscillator (T ₂ ) which is considered to propagate as S ₂₅ and S ₂₆
Therefore, the detector closest to the foot of the perpendicular line that descends from the point Q ₂ that is symmetrical to the object surface to the front part of the work vehicle will detect the reflected wave earliest. Therefore, a detector that is different from the case where ultrasonic waves are emitted from the ultrasonic oscillator (T ₁ ) is always selected by the signal comparison circuit (S).

From the above consideration, the output (Data2) of the signal comparison circuit (S) when the ultrasonic wave is emitted from the ultrasonic oscillator (T ₁ ) and the signal comparison circuit (S) when the ultrasonic wave is emitted from the ultrasonic oscillator (T ₂ ).
The outputs are compared, and if they are the same or if they are detector signals that are adjacent to each other, a program is made in the control circuit (3) so as to determine that the shape of the object is the edge state and otherwise the flat state. deep.

As a result, it is detected whether the object in front of the work vehicle is in the edge state or the flat state.

When the shape of the target object is detected in this way, the work vehicle and the target object are detected by using the ultrasonic wave propagation time data Data1 counted by the counting circuits (C ₁ ) (C ₂ ) ... (Cn) according to the shape. The distance to and is calculated.

The flow of such shape detection and distance detection is shown in FIG.

G) Effects of the Invention As described above, the shape determining apparatus of the present invention is configured to set a plurality of ultrasonic oscillators arranged on the same plane, a plurality of ultrasonic detectors provided between these ultrasonic oscillators, and Stagger,
When the means for outputting ultrasonic waves from the plurality of ultrasonic oscillators and the ultrasonic waves emitted by the plurality of ultrasonic oscillators are detected by the ultrasonic detectors, the shape of the object is determined by the detection pattern. Since the shape of a target object such as a wall is recognized, the distance can be accurately detected by a different calculation method depending on the shape, and the position of the work vehicle can be detected more accurately.

[Brief description of drawings]

FIG. 1 is a block diagram of the shape discriminating apparatus of the present invention, FIGS. 2 and 3 are schematic diagrams of states when ultrasonic waves are detected by the shape discriminating apparatus of the present invention, and FIG. 4 shows the operation of the shape discriminating apparatus of the present invention. The flowcharts shown in FIGS. 5, 5 and 6 are schematic state diagrams showing a conventional distance detecting method. (1) …… Work vehicle, (2) Interface, (3)…
… Control circuit, (T ₁ ) (T ₂ ) …… Ultrasonic oscillator, (P ₁ )
(P ₂ ) …… Drive circuit, (Ps ₁ ) (Ps ₂ ) …… Switch,
(R ₁ ) (R ₂ ) ... (Rn) ... Ultrasonic detector, (V ₁ ) (V ₂ ).
… (Vn) …… Ultrasonic receiving circuit, (C ₁ ) (C ₂ )… (Cn)…
… Counting circuit.

Claims (1)

[Claims] 1. A plurality of ultrasonic oscillators arranged on the same plane, a plurality of ultrasonic detectors provided between these ultrasonic oscillators, and ultrasonic transducers from the plurality of ultrasonic oscillators which are staggered at different times. A means for outputting a sound wave, and a means for determining the shape of the target object by the detection pattern when the ultrasonic waves emitted by the plurality of ultrasonic oscillators are respectively detected by the ultrasonic wave detector, Shape determination device consisting of.