JP2016081159A - Mobile entity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mobile entity which, when the position and/or posture of an object has changed due to contact between the object and the mobile entity, is able to reach the same object again targeting the changed position and/or posture.SOLUTION: A mobile entity comprises: a carriage for transporting an article to an object targeting a landmark that is set in the object; storage means 53 for storing the position and posture of the landmark of the object; control means 54 for autonomously controlling the carriage toward the object and making the carriage transport the article on the basis of the position and posture of the landmark of the object stored in the storage means; and detection means 4 for detecting the position and posture of the landmark of the object after the carriage and the object come in contact and the article is delivered. The storage means stores the position and posture of the landmark detected by the detection means.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a moving body that autonomously moves to carry an article.

  A moving body that autonomously moves to a target object based on landmarks installed in the environment is known (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 08-221123

  For example, when an object and a moving body are in contact with each other and an article is exchanged, the position and / or posture of the object may be shifted due to the impact of the contact. For this reason, when a mobile object tries to move to the same target object autonomously again, there exists a possibility that this target object cannot be reached.

  The present invention has been made to solve such a problem, and even if the position and / or posture of an object changes due to contact between the object and a moving body, the changed position and / or posture is targeted. The main object is to provide a moving object that can reach the same object again.

  In one aspect of the present invention for achieving the above object, a target is a landmark provided on an object, and a carriage unit that conveys an article to the object, and a position and an attitude of the landmark of the object Based on the position and orientation of the landmark of the object stored in the storage means, and autonomously controlling the carriage unit to the object and transporting the article to the carriage unit Means for detecting the position and orientation of the landmark of the object after the carriage and the object are in contact with each other and the article is transferred. The means is a moving body that stores the position and orientation of the landmark detected by the detecting means.

  According to the present invention, even if the position and / or orientation of a landmark of an object changes due to contact between the object and a moving object, the same object is reached again with the changed position and / or orientation as a target. A movable body that can be provided can be provided.

It is a block diagram which shows the schematic system configuration | structure of the moving body which concerns on Embodiment 1 of this invention. (A) It is a figure for demonstrating the moving method of a moving body. (B) It is a figure for demonstrating the moving method of a moving body. (C) It is a figure for demonstrating the moving method of a moving body. (D) It is a figure for demonstrating the moving method of a moving body. (E) It is a figure for demonstrating the moving method of a moving body. It is a block diagram which shows the schematic system configuration | structure of the control apparatus which concerns on Embodiment 1 of this invention. It is a flowchart which shows the memory | storage process flow of the landmark memory | storage part which concerns on Embodiment 1 of this invention. It is an example of the characteristic figure which shows the relationship between the relative angle and relative distance of a landmark with respect to a camera, and the detection accuracy of the position and attitude | position of a landmark. It is a figure which shows the timing which memorize | stores the position and attitude | position of a landmark in an environmental coordinate system. It is a flowchart which shows the memory | storage process flow of the landmark memory | storage part which concerns on Embodiment 2 of this invention.

Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic system configuration of a moving object according to Embodiment 1 of the present invention. The moving body 1 according to the first embodiment autonomously conveys an object such as a box to or from an object such as a shelf.
The moving body 1 includes a carriage unit 2 for conveying articles, a moving body detection sensor 3 for detecting the position of the moving body 1, a landmark detection sensor 4 for detecting a landmark of an object, and a carriage unit. And a control device 5 for controlling the movement of.

  The carriage unit 2 includes a carriage main body 21 on which an article such as a box is placed, and a moving device 22 that moves the carriage main body 21. The cart body 21 has, for example, a frame structure having a plurality of defined spaces. The cart body 21 is provided with a space for receiving an empty box from an object such as a shelf and placing the empty box, a space for placing an actual box to be passed to the object, and the like. The cart body 21 is provided with a connecting portion that connects to the object. The cart body 21 connects the connecting portion to the object when transferring the object and the article. In addition, the structure of the said trolley | bogie part 2 is an example, and is not limited to this.

  The moving device 22 includes, for example, a plurality of wheels and a drive unit 221 such as a motor that drives each wheel. The drive unit 221 moves the carriage unit 2 by driving each wheel in accordance with a control signal output from the control device 5. In addition, although the moving apparatus 22 is the structure which moves the trolley | bogie part 2 by driving each wheel, it is not limited to this. The moving device 22 has, for example, a plurality of legs, and the carriage 2 may be moved by driving each leg.

  The moving body detection sensor 3 is provided in the carriage unit 2 and is a sensor for detecting the position and posture of the moving body 1. The moving body detection sensor 3 includes, for example, a laser range finder, a stereo camera, a three-dimensional sensor, a wheel encoder provided on each wheel, and the like. The moving body detection sensor 3 outputs sensor values relating to the detected position and orientation of the moving body 1 to the control device 5.

  The landmark detection sensor 4 is provided in the carriage unit 2 and is a sensor for detecting the position and orientation of the landmark of the object. The landmark detection sensor 4 is composed of, for example, a monocular camera or a stereo camera. The landmark detection sensor 4 outputs a sensor value related to the position and orientation of the detected landmark to the control device 5. The landmark is, for example, a geometric pattern provided on the side of an object such as a shelf. The moving body 1 moves using the landmark of the object as a target mark.

The control device 5 autonomously moves the moving body 1 by controlling the moving device 22 of the carriage unit 2 based on the sensor value output from the moving body detection sensor 3 and the route information set in advance. Let
The control device 5 includes, for example, a CPU (Central Processing Unit) 5a that performs control processing, arithmetic processing, and the like, a ROM (Read Only Memory) 5b that stores a control program executed by the CPU 5a, an arithmetic program, processing data, and the like. The hardware configuration is centered on a microcomputer including a RAM (Random Access Memory) 5c and the like.

2A to 2E are views for explaining a moving method of the moving body. Here, the case where the mobile body 1 conveys the box which is an article | item to the shelf which is a target object, for example is assumed.
First, the user activates the moving body 1 that stands by in the initial waiting area (FIG. 2A).
The control device 5 autonomously moves the moving body 1 to the shelf by controlling the moving device 22 based on the sensor value output from the moving body detection sensor 3 and the route taught in advance (see FIG. 2 (b)).

  When the moving body 1 approaches the shelf, the control device 5 controls the moving apparatus 22 so that the moving body 1 faces in a direction in which a landmark is predicted. And the control apparatus 5 recognizes the position and attitude | position of a landmark based on the sensor value output from the landmark detection sensor 4 (FIG.2 (c)).

  The control device 5 controls the moving device 22 so that the connecting portion of the carriage main body 21 is connected to the shelf (FIG. 2D). At this time, the position of the shelf shifts due to an impact when the connecting portion of the carriage main body 21 and the shelf are connected. The shelf is, for example, a movable shelf having casters on the lower surface. Therefore, there is a possibility that the shelf is largely displaced due to the impact at the time of connection. The control device 5 moves the box of the carriage main body 21 to the shelf after connecting the connecting portion of the carriage main body 21 to the shelf. The control device 5 moves the box of the carriage main body 21 to the shelf, and then removes the moving body 1 from the shelf.

  The control device 5 autonomously moves the moving body 1 to the initial standby area by controlling the moving device 22 based on the sensor value output from the moving body detection sensor 3 and the route taught in advance. (FIG. 2 (e)).

  As described above, when an article is exchanged, the position and / or posture of the object may be shifted due to the impact of this contact. For this reason, when the conventional mobile body tries to move to the same object autonomously again, there is a possibility that this object cannot be reached.

  On the other hand, the moving body 1 according to the present embodiment detects the position and orientation of the landmark of the target object after the carriage unit 2 and the target object are in contact with each other and the article is transferred, and the detected land Stores the position and orientation of the mark. As a result, even if the position and / or orientation of the landmark of the object changes due to the contact between the object and the moving body 1, the moving body 1 is again the same with the stored position and orientation of the landmark as a target. You can reach the object.

FIG. 3 is a block diagram illustrating a schematic system configuration of the control device according to the first embodiment.
The control device 5 according to the present embodiment includes a moving body detection unit 51, a landmark detection unit 52, a landmark storage unit 53, and a moving body control unit 54.

  The moving body detection unit 51 is based on the sensor value output from the moving body detection sensor 3, and the position and orientation of the moving body 1 in a coordinate system (hereinafter referred to as an environmental coordinate system) based on the environment in which the moving body 1 moves. Is recognized with an accuracy of ± 10 cm, for example. The moving body detection unit 51 outputs the recognized position and orientation of the moving body 1 in the environmental coordinate system to the landmark storage unit 53 and the moving body control unit 54.

  Based on the sensor value output from the landmark detection sensor 4, the landmark detection unit 52 determines the position and orientation of the landmark of the target object in a coordinate system based on the moving body 1 (hereinafter referred to as a moving body coordinate system). For example, detection is performed with an accuracy of ± several mm. The landmark detection unit 52 is a specific example of detection means. The landmark detection unit 52 outputs the detected position and orientation of the landmark in the moving body coordinate system to the landmark storage unit 53.

  The landmark storage unit 53 is a specific example of the storage unit, and stores the position and orientation of the landmark in the environmental coordinate system. The landmark storage unit 53 includes, for example, the ROM 5b and the RAM 5c. FIG. 4 is a flowchart showing a storage processing flow of the landmark storage unit according to the first embodiment.

The landmark storage unit 53 acquires the position and orientation of the landmark in the moving object coordinate system from the landmark detection unit 52 (step S101).
The landmark storage unit 53 determines whether or not the position and orientation of the landmark in the moving object coordinate system from the landmark detection unit 52 satisfy a predetermined condition (step S102). For example, the landmark storage unit 53 determines the predetermined condition as follows.

  First, the landmark storage unit 53 calculates the relative distance and relative angle of the landmark with respect to the landmark detection sensor 4 based on the position and orientation of the landmark from the landmark detection unit 52. Here, for example, a case where the camera 4 is used as the landmark detection sensor 4 is assumed. In this case, when the relative distance between the camera 4 and the landmark is short and the relative angle of the landmark with respect to the camera (photographing direction) 4 is within a predetermined range, the detection accuracy of the position and orientation of the landmark is high.

  FIG. 5 is an example of a characteristic diagram showing a relationship between the relative angle and relative distance of the landmark with respect to the camera and the detection accuracy of the position and orientation of the landmark. Measurement with a camera is performed in advance, and it can be seen that the detection accuracy of the position and orientation of the landmark increases in the shaded portion near the origin shown in FIG.

  For example, the landmark storage unit 53 determines that the predetermined condition is satisfied when the calculated relative distance and relative angle of the landmark to the landmark detection sensor 4 fall within the hatched portion S of FIG.

  When the landmark storage unit 53 determines that the position and orientation of the landmark in the moving object coordinate system from the landmark detection unit 52 satisfies the predetermined condition (YES in step S102), the landmark storage unit 53 receives the environmental coordinate system from the moving object detection unit 51. The position and orientation of the moving body 1 are acquired (step S103). When the landmark storage unit 53 determines that the position and orientation of the landmark in the moving object coordinate system from the landmark detection unit 52 do not satisfy the predetermined condition (NO in step S102), the landmark storage unit 53 returns to the above (step S101).

  The landmark storage unit 53 is based on the position and orientation of the landmark in the moving object coordinate system from the landmark detection unit 52 and the position and orientation of the moving object 1 in the environmental coordinate system from the moving object detection unit 51. The position and orientation of the landmark in the environmental coordinate system are calculated (step S104).

The landmark storage unit 53 stores the calculated landmark position and orientation in the environmental coordinate system as the current landmark position and orientation (step S105).
In addition, for example, in a box transporting operation in which a landmark is provided on a shelf with casters and the mobile body 1 is connected to the shelf and transports a box, the mobile body 1 is connected to the shelf. Is likely to be displaced (FIG. 2D). Accordingly, the moving body 1 is connected to the shelf, finishes transporting the box and leaves the shelf, and the moving body 1 leaves the shelf to some extent. The landmark storage unit 53 stores the position and orientation of the landmark in the environmental coordinate system at that time. For example, as shown in FIG. 6, the landmark storage unit 53 stores the position and orientation of the landmark in the environmental coordinate system when the relative distance between the camera 4 and the landmark reaches a predetermined threshold.

The moving body control unit 54 is a specific example of a control unit, and calculates a speed target value for controlling the position and orientation of the moving body 1. The mobile control unit 54 performs feedback control with the target landmark position and orientation as target values. For example, when the landmark detection unit 52 detects a landmark, the moving body control unit 54 detects the position and orientation of the moving body 1 in the environmental coordinate system output from the moving body detection unit 51, and the landmark storage unit 53. Based on the position and orientation of the landmark acquired from the above, the speed target value of the moving body 1 is set so that the target landmark falls within the detection range of the landmark detection sensor 4 (for example, the hatched portion in FIG. 5). Is calculated.
The moving body control unit 54 controls the position and orientation of the moving body 1 by outputting a control signal corresponding to the calculated speed target value to the moving device 22.

  As described above, the moving body 1 according to the first embodiment detects the position and orientation of the landmark of the target object after the cart unit 2 and the target object are in contact with each other and the article is transferred, and the detected landmark is detected. The position and posture are stored. As a result, even if the position and / or orientation of the landmark of the object changes due to the contact between the object and the moving body 1, the moving body 1 is again the same with the stored position and orientation of the landmark as a target. You can reach the object.

Embodiment 2
In the second embodiment of the present invention, the landmark storage unit 53 determines predetermined conditions for the relative distance and relative angle of the landmarks, and further determines the moving speed of the moving body 1 to determine the land in the environmental coordinate system. The position and orientation of the mark are stored.

  As described above, the relative distance and relative angle of the landmark with respect to the landmark detection sensor 4 affect the detection accuracy of the position and orientation of the landmark. However, the moving speed of the moving body 1 also detects the position and orientation of the landmark. Affects accuracy. For example, when a camera is used as the landmark detection sensor 4, if the camera moves at a high speed, the detection accuracy of the landmark is greatly lowered due to the effect of motion blur, and the landmark detection unit may not be able to detect the landmark. is there.

  Accordingly, when the landmark storage unit 53 according to the second embodiment satisfies the predetermined conditions of the relative distance and the relative angle of the landmark and determines that the moving speed of the moving body 1 is equal to or less than a predetermined value, Stores the position and orientation of the landmark in the coordinate system. Thereby, the detection accuracy of the position and orientation of the landmark can be further improved. Note that the landmark storage unit 53 may store the position and orientation of the landmark in the environmental coordinate system when, for example, it is determined that the rotational speed of the wheel of the moving device 22 is a predetermined value or less.

FIG. 7 is a flowchart showing a storage processing flow of the landmark storage unit according to the second embodiment.
The landmark storage unit 53 acquires the position and orientation of the landmark in the moving object coordinate system from the landmark detection unit 52 (step S201).

  The landmark storage unit 53 determines whether or not the landmark position and orientation in the moving object coordinate system from the landmark detection unit 52 satisfy the predetermined conditions of the relative distance and relative angle of the landmark (step S202).

  When the landmark storage unit 53 determines that the position and orientation of the landmark in the moving object coordinate system from the landmark detection unit 52 satisfy the predetermined conditions of the relative distance and relative angle of the landmark (YES in step S202). It is determined whether or not the moving speed of the moving body 1 is equal to or less than a predetermined value (step S203).

  When the landmark storage unit 53 determines that the moving speed of the moving body 1 is equal to or less than the predetermined value (YES in step S203), the landmark storage unit 53 acquires the position and orientation of the moving body 1 in the environmental coordinate system from the moving body detection unit 51. (Step S204).

  The landmark storage unit 53 is based on the position and orientation of the landmark in the moving object coordinate system from the landmark detection unit 52 and the position and orientation of the moving object 1 in the environmental coordinate system from the moving object detection unit 51. The position and orientation of the landmark in the environmental coordinate system are calculated (step S205).

The landmark storage unit 53 stores the calculated landmark position and orientation in the environmental coordinate system as the current landmark position and orientation (step S206).
When the landmark storage unit 53 determines that the position and orientation of the landmark in the moving object coordinate system from the landmark detection unit 52 do not satisfy the predetermined conditions for the relative distance and relative angle of the landmark (NO in step S202). Return to the above (step S201).

  When the landmark storage unit 53 determines that the moving speed of the moving body 1 is greater than the predetermined value (NO in step S203), the landmark storage unit 53 returns to the above (step S201). In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 1 Mobile body, 2 trolley | bogie part, 3 mobile body detection sensor, 4 landmark detection sensor, 5 control apparatus, 51 mobile body detection part, 52 landmark detection part, 53 landmark storage part, 54 mobile body control part

Claims (1)

Targeting a landmark provided on the object, a carriage unit for conveying an article to the object;
Storage means for storing the position and orientation of the landmark of the object;
And a control unit that autonomously controls the carriage unit to the object based on the position and orientation of the landmark of the object stored in the storage unit and transports the article to the carriage unit. Because
A detecting means for detecting a position and an attitude of the landmark of the object after the carriage and the object are in contact with each other and the article is transferred;
The moving body characterized in that the storage means stores the position and orientation of the landmark detected by the detection means.

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