JP2006163558A - Control device of moving truck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of moving a truck capable of inexpensively identifying an object by a simple method even from a relatively remote place without setting a device such as a transceiver on the object or setting an exclusive transceiver on a moving truck. <P>SOLUTION: The moving truck 1 is mounted with a direction and distance detection sensor 3 capable of measuring information for the direction and distance to an external environment. In an object identification part 4, the distance between points where distance information obtained from the sensor 3 is varied by a predetermined threshold or more, compared with the direction of its vicinity is calculated, and when this distance is matched to the outer shape of a preliminarily designated object 6 within a predetermined error range, the part between the points is identified as the object 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for a mobile carriage that performs predetermined work by leaning on a load port, a work table, a desk, or the like in a factory, medical welfare facility, home, or the like.

2. Description of the Related Art In recent years, systems using a mobile robot that autonomously travels with a moving carriage such as a wheel and performs a predetermined operation with a robot arm have been provided in factories, medical welfare facilities, and homes.
In such a system, in order to enable the work by the robot arm, it is necessary to first bring the movable carriage close to the work object such as the load port, the work table, and the desk. In particular, in the case of a trackless mobile trolley in which a guide or the like is not laid on the floor surface, a function for identifying a work object from other objects and accurately measuring the position thereof, that is, an object identification function is required.
As a method for identifying the object of the mobile carriage, for example, a method of identifying an object by installing ultrasonic transceivers on both the object and the mobile carriage and measuring the distance between the transceivers is as follows: It is proposed in Patent Document 1 shown.

FIG. 5 is an overall configuration diagram of the mobile robot system in Patent Document 1 showing the prior art as viewed from above.
In the figure, 1 is a mobile carriage, 2 is a drive unit mounted on the mobile carriage 1 and driving the mobile carriage, and 101 and 102 are ultrasonic transmitters / receivers that detect objects existing around the mobile carriage 1. is there. Reference numeral 4 denotes an object identification unit for identifying a target object based on the detection information of the ultrasonic transceivers 101 and 102, and 5 denotes the progress of the mobile carriage 1 based on the identification information of the object identification unit 4. A command transmission unit 5 that determines a direction and transmits a control command to the drive unit 2. Further, 103 and 104 are ultrasonic transceivers installed at the end points of the object 6 to be approached. The ultrasonic transceivers 103 and 104 are supplied with a power source from a power source (not shown), and are connected to a signal generator (not shown) to control transmission / reception of ultrasonic waves.

Hereinafter, a method for identifying an object in the prior art will be described.
When the ultrasonic transmitter / receiver 101 on the mobile carriage 1 transmits an ultrasonic wave at time t ₀ , the ultrasonic transmitter / receivers 103 and 104 on the object have times t ₁ and t at which time differences occur according to the distances Rl and Rr. ₂ receives the ultrasonic waves. When the ultrasonic transmitters / receivers 103 and 104 return ultrasonic waves after Δt time after reception, the ultrasonic transmitter / receiver 101 receives the ultrasonic waves at times t ₃ and t _{4 at} which further time differences occur. Here, using the time from when the ultrasonic transceiver 101 transmits and receives the ultrasonic wave and the propagation velocity v of the ultrasonic wave in the space, the distances Rl and Rr are Rl = {(t ₃ −t _0. ) −Δt} × v / 2
Rr = {(t ₄ −t ₀ ) −Δt} × v / 2
Is required. In the ultrasonic transceiver 102, the distances Ll and Lr can be similarly obtained, and the position and orientation of the movable carriage 1 relative to the object 6 can be calculated from the above Rl, Rr, Ll, and Lr.

As described above, in the conventional mobile cart shown in Patent Document 1, transmitters are installed at both ends of an object, and a receiver is installed in the mobile cart to measure the distance between the transceivers. Can be identified.
Patent No. 3018837 (6th page, FIG. 7)

However, in the prior art, it is necessary to install a dedicated transmitter / receiver on the moving carriage and the object, and there is a problem that a great deal of cost is required. In particular, in the case of a mobile robot operating in a home or facility, it is practically impossible to install a transmitter / receiver on all objects such as desks and refrigerators due to cost problems, power supply securing problems, and maintenance problems.
On the other hand, in recent years, ID tags that can supply power from the outside without contact have been proposed. If these tags are spread and embedded in all objects, it is considered effective for identifying the objects. However, there are problems that the recognizable distance is short at present and the position of the object cannot be measured accurately.

  The present invention has been made in view of such problems, and it is relatively far away without installing a device such as a transmitter / receiver on an object and without installing a dedicated transmitter / receiver on a mobile carriage. It is an object of the present invention to provide a control device for a mobile carriage that can identify an object even from a place by an inexpensive and simple method.

  In order to solve the above problems, the present invention is configured as follows.

  The invention of claim 1 includes a moving carriage, a drive unit mounted on the moving carriage for driving the moving carriage, a sensor unit for detecting an object existing around the moving carriage, and detection information of the sensor. An object identification unit for identifying a target object based on the original, a command for determining a traveling direction of the mobile carriage based on the identification information of the object identification unit, and transmitting a control command to the drive unit In the control apparatus for a mobile carriage including a transmission unit, the sensor unit is configured by a direction distance detection sensor capable of measuring information on a direction and a distance from an external environment, and the object identification unit is configured by the sensor. When the distance information obtained from the part calculates the distance between points where the distance information changes more than a predetermined threshold compared to the direction of the vicinity, and the distance matches the contour of the object specified in advance within a predetermined error range Next, identify the object between the points And it is characterized in and.

  Moreover, the invention of claim 2 is the mobile trolley control apparatus according to claim 1, wherein the command transmitting unit uses a line segment connecting the end points of the object obtained from the object identifying unit to the object. It is a proximity surface, and the control command of the movable carriage is transmitted so as to be in a predetermined position / posture with respect to the proximity surface.

  According to a third aspect of the present invention, in the mobile trolley control apparatus according to the first aspect, the sensor section continuously changes the measurement direction, thereby continuously providing information on the direction and distance to the outside environment. It is characterized in that it is configured by what can be acquired.

  According to a fourth aspect of the present invention, in the mobile trolley control apparatus according to the first aspect, the measurement direction is fixed, and the drive unit turns the mobile trolley in response to a command from the command transmission unit. The information on the direction and the distance is continuously acquired.

  Further, the invention of claim 5 is the mobile trolley control apparatus according to claim 1, wherein the object identification unit starts to project a point where the distance information acquired from the sensor unit has changed in a negative direction by a predetermined threshold value or more. It is characterized in that the point is the point, and the point immediately preceding the point that has changed in the positive direction beyond a predetermined threshold is the convex end point.

  The invention according to claim 6 is the control device for a mobile carriage according to claim 1, wherein the object identifying unit is one of the points where the distance information acquired from the sensor unit has changed in the positive direction by a predetermined threshold value or more. The previous point is a concave start point, and the next point that changes in a negative direction by a predetermined threshold or more is a concave end point.

  The invention of claim 7 is the mobile trolley control apparatus according to claim 1, 3 or 4, wherein the sensor unit is configured to contactlessly store identification information stored in a storage medium installed on the object. It includes a readable object identification device.

  According to the first aspect of the present invention, a device such as a transmitter / receiver is not required for an object, and a sensor used for detecting obstacles is also used for a moving carriage only when approaching. Is unnecessary. Furthermore, by using a laser sensor, an object can be detected with high accuracy even from a relatively remote location.

  According to the second aspect of the present invention, it is possible to approach an object in an arbitrary position and orientation.

  According to the third aspect of the invention, it is not necessary to turn the moving body at the time of measurement, so that the object can be detected in a short time.

  According to the fourth aspect of the present invention, the distance sensor that can measure only in one direction can be used, so that the cost can be reduced.

  According to the invention described in claim 5, it is possible to detect a convex object such as a desk or a load port.

  According to the invention described in claim 6, it is possible to detect a concave object such as an open door or an elevator.

  According to the seventh aspect of the invention, it is possible to achieve both unique recognition of an object and accurate position detection.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of a mobile robot showing a first embodiment of the present invention as viewed from above. Note that FIG. 1 has the same configuration with respect to the prior art shown in FIG. 5 except for a part, and the same reference numerals indicate the corresponding parts.
In the figure, 1 is a moving carriage, 2 is a drive unit, 3 is a sensor unit for detecting an object existing around the moving carriage 1, and 4 is a target object 6 based on detection information of the sensor unit 3. An object identification unit 5 to be identified is a command transmission unit that determines a traveling direction of the mobile carriage 1 based on identification information of the object identification unit 4 and transmits a control command to the drive unit 2.
The features of the present invention are as follows.
That is, the sensor unit 3 uses a direction distance detection sensor capable of measuring information on the direction and distance from the outside environment. As the directional distance detection sensor, for example, a laser type area sensor that is typically used for obstacle detection and the like is adopted as a typical one, and the sensor has an area within a predetermined angle range, for example, in a counterclockwise direction. Scanning is performed while changing the direction for each corner, and data composed of a set of a predetermined direction and a distance to the nearest object existing in the direction can be continuously output. When the output data of the directional distance detection sensor is plotted on FIG. 1, it becomes like a black dot in the figure. Here, when the target object 6 has a shape protruding in the depth direction from another external environment (for example, a wall) such as a load port or a desk, the distance information is the end point of the target object 6 as shown in FIG. It changes greatly in the vicinity of 11 and 12. Therefore, it can be recognized as the end point of the object 6 by detecting this.
As another feature, the object identification unit 4 calculates a distance between points where the distance information obtained from the sensor unit 3 changes by a predetermined threshold or more compared to the direction of the neighborhood, and the distance is calculated in advance. This is a point having a function of identifying a point as an object when it matches the outer shape of the specified object 6 within a predetermined error range.

Next, the operation will be described.
In FIG. 1, when the sensor unit 3 provided on the movable carriage 1 scans an area of a predetermined angle range with respect to the object 6 while changing the direction counterclockwise at every predetermined step angle, Data consisting of a pair with the distance to the closest object existing in that direction is continuously output. Subsequently, in the object identification unit 4, the sensor information obtained by inspecting the set of the direction and distance information with respect to the object 6 using the sensor in the order of the counterclockwise direction is compared with the immediately preceding direction. If the distance information changes in the negative direction (becomes smaller) than the predetermined threshold, the negative direction is determined as the convex start point, and further inspection is continued, and the distance information changes in the positive direction beyond the predetermined threshold. The direction immediately before the increased (increased) direction is determined as the convex end point. When the object identification unit 4 completes the detection of the convex start point and the convex end point of the object 6, the distance between the two points is calculated and matches the external shape of the object 6 specified in advance within a predetermined error range. In addition, the point 6 is identified as the object 6. On the other hand, when the distance exceeds a predetermined error range, it is not regarded as the object 6 and is ignored.

FIG. 2 is a top view showing a method of approaching an object in the present embodiment. Note that some of the same parts as those in FIG. 1 are omitted.
When the object identification unit 4 recognizes the end point of the object 6 by the method shown in FIG. 1, the command transmission unit 5 displays the line segment connecting the end point 11 and the end point 12 of the object 6, and the object 6 is the moving carriage 1. Is the closest surface, that is, the proximity surface. Subsequently, the target point of the movable carriage 1 is determined so as to be in a predetermined position / posture with respect to the proximity surface. For example, when it is desired to approach the moving carriage 1 with a predetermined distance L in parallel with the object 6, it is on a perpendicular bisector connecting the end points 11 and 12, that is, on the center line CC of the object 6. A point that is a distance L away from the object 6 is a target point.

Since the first embodiment has the above-described configuration, it is possible to eliminate the need for a device such as a transmitter / receiver that has been provided for the object 6 in the related art, and the mobile carriage 1 also uses a sensor that is normally used for obstacle detection. Is used only when approaching, a dedicated transceiver can be dispensed with.
Furthermore, by using a laser sensor as the sensor 3, it is possible to detect the object with high accuracy even from a relatively remote location. Then, by controlling the moving carriage 1 with the end point of the object 6 as the proximity plane, the movement carriage 1 can be brought close to the proximity plane of the object 6 with any position and orientation.

FIG. 3 is a top view of a mobile robot showing a second embodiment of the present invention.
The second embodiment is different from the first embodiment in that the sensor unit 3 that does not have a scanning function like a laser type area sensor and that can measure the distance only in one direction is used instead of scanning the sensor 3. The cart itself is configured to turn on the spot, and a set of a turning angle and a measurement distance is used as direction distance information.
Since the second embodiment has the above-described configuration, the direction distance information can be obtained without using an expensive laser area sensor, so that the cost can be further reduced.

FIG. 4 is a top view of a mobile robot showing a third embodiment of the present invention.
In the third embodiment, the object 6 is a gap such as a door or an elevator, and a method for passing through the gap is provided. Contrary to the convex portion detection in the first embodiment, the concave portion can be detected. It differs in the point of the structure made. Specifically, the set of direction and distance information is inspected in the counterclockwise direction, and the distance information is changed to a positive direction by a predetermined threshold or more (increased) in the forward direction compared to the immediately preceding direction. The direction is determined as the concave start point. Further, the inspection is continued, and the concave end point is determined based on the direction in which the distance information has changed (decreased) in the negative positive direction after a predetermined threshold.
Since the third embodiment is configured as described above, it is possible to easily identify gaps such as doors and elevators without using a device such as a transceiver.

In the above embodiment, the object is identified by using only the direction distance detection sensor. However, when there are a plurality of objects having the same shape in the sensor field of view, it is difficult to discriminate only by the outer shape. . In such a case, the ID tag sensor as described above can be embedded in the object, and the type of the object can be directly recognized by the ID tag reading device on the mobile carriage side.
Thereby, the unique recognition of the target object by an ID tag sensor and the exact position detection by a laser sensor can be made compatible.

  Although the present invention presents a method for identifying an approaching object of a moving carriage, it can be similarly applied as a method for identifying a grasping object of a robot arm mounted on a moving carriage.

1 is an overall configuration diagram of a mobile robot according to a first embodiment of the present invention as viewed from above. The figure which shows the approach method to the target object in a present Example The top view of the mobile robot which shows 2nd Example of this invention The top view of the mobile robot which shows 3rd Example of this invention Overall configuration diagram of the mobile robot system in Patent Document 1 showing the prior art viewed from above

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile trolley 2 Drive part 3 Sensor part 4 Object identification part 5 Command transmission part 6 Object 11, 12 End point

Claims (7)

A mobile trolley,
A drive unit mounted on the movable carriage for driving the movable carriage;
A sensor unit for detecting an object existing around the movable carriage;
An object identification unit for identifying a target object based on detection information of the sensor;
A command transmission unit for determining a traveling direction of the mobile carriage based on the identification information of the object identification unit, and transmitting a control command to the drive unit;
In the control apparatus of the mobile carriage provided with
The sensor unit is composed of a direction distance detection sensor capable of measuring information on the direction and distance with the outside environment,
The object identification unit calculates a distance between points where the distance information obtained from the sensor unit changes by a predetermined threshold or more compared to a direction in the vicinity, and the distance is set to an outline of the object specified in advance. A control apparatus for a mobile carriage characterized by identifying a point as an object when they coincide within a predetermined error range.   The command transmission unit sets a line segment connecting the end points of the target object obtained from the target object identification unit as a proximity surface of the target object, and the moving carriage so as to have a predetermined position and posture with respect to the proximity surface 2. The control apparatus for a mobile carriage according to claim 1, wherein the control command is transmitted.   The mobile trolley according to claim 1, wherein the sensor unit is configured to continuously acquire information on a direction and a distance from an external environment by continuously changing a measurement direction thereof. Control device.   The sensor unit has a fixed measurement direction, and the drive unit continuously acquires information on the direction and distance from the outside environment by turning the movable carriage in response to a command from the command transmission unit. The control apparatus of the moving trolley | bogie of Claim 1.   The target object identification unit sets a point at which the distance information acquired from the sensor unit has changed in a negative direction by a predetermined threshold or more as a convex start point, and then a point immediately before a point by which the distance information has changed in a positive direction by a predetermined threshold or more. 2. The control device for a mobile carriage according to claim 1, wherein the point is a convex end point.   The target object identification unit sets the point immediately before the point where the distance information acquired from the sensor unit has changed in the positive direction over a predetermined threshold as a concave start point, and then changed in the negative direction over a predetermined threshold. 2. The control device for a mobile carriage according to claim 1, wherein the point is a concave end point.   5. The mobile carriage according to claim 1, wherein the sensor unit includes an object identification device capable of reading identification information stored in a storage medium installed on the object in a non-contact manner. Control device.

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