JP2005144606A - Moving robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moving robot capable of preventing erroneous recognition of a robot arm as an obstacle, even when the robot arm passes through a detectable range of an area sensor, by simultaneously operating a moving carriage and the robot arm. <P>SOLUTION: A control means 5 of the moving robot 1 has an arm position calculating part 505 for calculating a position of an area A2 where the robot arm 3 crosses an area A1 when the robot arm 3 passes through the detectable area A1 of the area sensor 4, a detecting area setting part 501 for setting a range of excluding the area A2 from the area A1 as a detecting area, an obstacle map making part 502 for making a distribution map of the obstacle based on a distance and direction information acquired by the area sensor 4, an obstacle detecting part 503 for detecting the existence of the obstacle by comparing the detecting area with the obstacle distribution map, and an obstacle avoiding planning part 504 for transmitting an avoiding command to the moving robot 1 when the obstacle exists. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a mobile robot that performs a predetermined operation with a robot arm 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, it is necessary to ensure safety when a mobile robot and a person coexist without a safety fence. For this reason, many methods have been disclosed in which an obstacle sensor is provided in a mobile robot to detect surrounding objects and a safety ensuring operation such as obstacle avoidance or stop is performed based on the detection result. Among them, a method has been proposed in which a distance measurement type area sensor is used as an obstacle sensor and a detection area is set according to the shape of a known fixed facility (work station) (for example, see Patent Document 1). .
FIG. 7 is a top view for explaining the configuration of the mobile robot showing the prior art.
In the figure, 1 is a mobile robot, 2 is a mobile trolley for driving the mobile robot, 3 is a robot arm mounted on the mobile trolley, 4a to 4d are distance measuring area sensors arranged around the mobile trolley, Control means for driving and controlling the movable carriage 2 and the robot arm 3. The movable carriage 2 moves in the direction of arrow a on the travel path.
As a general area sensor, a laser type area sensor is used as a typical one, and an area within a predetermined angle range is scanned while changing the angle step by step, and coordinate calculation is performed based on the distance of the object and its angle. It has an operation principle of detecting an obstacle in a set area. For this reason, for example, the detectable area A1 of the area sensor 4a forms a so-called fan-shaped area within a predetermined angular range and a predetermined radius in the horizontal direction.
When the operator enters the detectable area A1 of the area sensor 4a, information on the detected distance and direction of the object is transmitted to the control means 5. Based on this information, the control means 5 stops the robot arm 3 or transmits an operation command for avoiding an obstacle to the mobile carriage 2 to ensure safety.
Furthermore, in Patent Document 1, when the robot arm 3 is operated in a state where the fixed facility 6 exists in the detectable area A1, only the other true obstacles are detected without erroneously recognizing the fixed facility 6 as an obstacle. Mention how to detect. That is, the control means 5 excludes a portion corresponding to the fixed equipment 6 from the detectable area A1 of the area sensor 4a, and sets the remaining area A3 as a detection area. Then, the safety ensuring operation is executed only for the obstacle detected in the detection area A3.
FIG. 8 is a flowchart showing a processing procedure in the conventional example.
Realization of mainly safety functions executed by the control means 5 from the time when the mobile robot 1 arrives in front of the fixed equipment 6 until the robot arm 3 performs the work and moves toward the next fixed equipment after the work is completed. It is a flowchart which shows the procedure of the process regarding (obstacle detection). Here, it is assumed that the detection area A3 of the area sensor 4 in each fixed facility is set in advance according to the shape of the fixed facility.
When the mobile robot 1 arrives at the work position in front of the fixed equipment 6 and stops at step ST11, the actual stop position is recognized using the area sensor 4 at the next step ST12, and the work position at teaching Differences in the X, Y, and θ directions are detected. Based on the difference, correction of the operation point of the robot arm 3 and correction of the detection area A3 are performed.
Next, in steps ST13 to ST15, an area sensor self-diagnosis is performed, which is omitted because it is not directly related to this patent. When the self-diagnosis is completed, work by the robot arm is started in step ST16, and in step ST17, the area sensor 4 is turned on to monitor whether an obstacle has entered the detection area A3. At this time, as shown in FIG. 6, the detection area A <b> 3 is set so as to follow the shape of the fixed equipment 6, so that a blind spot can be eliminated in the detection area of the area sensor 4.
Next, in step ST18, it is determined whether or not an obstacle has entered the detection area A3. If there is no entry (No), the operation by the robot arm 3 is continuously executed in step ST19. The
On the other hand, when an operator or another robot enters the detection area A3 (Yes), the area sensor 4 detects the intrusion of the obstacle and outputs an ON signal, and the control means 5 performs step ST20. The operation of the robot arm 3 is temporarily stopped.
Thereby, the safety of the worker is ensured. Further, when an obstacle leaves the detection area A3 in the temporary stop state, the output of the area sensor 4 is turned off, and the operation by the robot arm 3 is resumed.
Then, in step ST21, it is determined whether or not the work in the fixed facility 6 is finished. When the work is finished (Yes), the robot arm 3 is moved to the origin position in step ST22, and the area sensor 4 is turned off. Then, the mobile robot 1 moves toward the next fixed facility. Even when the mobile robot 1 moves, obstacle detection in the traveling direction is performed by an area sensor in front of the movement direction or another obstacle sensor, and the movement is stopped when an obstacle is detected. .
As described above, in the conventional mobile robot shown in Patent Document 1, the distance measuring type area sensor is used as the obstacle sensor, and the detection area is set according to the shape of the known fixed equipment. Only other true obstacles can be detected without erroneously recognizing the obstacle.
Japanese Patent Application Laid-Open No. 2002-264070 (see pages 4 to 6 of the specification, FIG. 1 and FIG. 4)

However, in the conventional mobile robot shown in Patent Document 1, it is assumed that the robot arm 3 operates only when the mobile carriage 2 is stopped, and the operation range of the robot arm 3 is in the detectable area A1 of the area sensor 4. It is assumed that it will not invade. For this reason, the process of excluding the fixed equipment 6 from the detection area is only performed once after the moving carriage stops, and the robot arm is not an object of exclusion in the first place. However, in recent home service robots that have been proposed, it is normal that the moving carriage and the robot arm operate at the same time, and since the operation range of the robot arm is wide, the robot arm moves within the detectable area A1 of the area sensor 4. 3 may also pass. In such a case, the conventional technique has a problem that the control means 5 erroneously recognizes the robot arm 3 detected by the area sensor 4 as an obstacle. If erroneous recognition occurs, the robot arm 3 may stop due to its own detection result, or the mobile carriage 2 may perform obstacle avoidance movements to avoid the robot arm 3, which may interfere with actual work.
The present invention has been made to solve the above-described problem. Even when the moving carriage and the robot arm operate at the same time and the robot arm passes the detectable range of the area sensor, the robot arm is erroneously regarded as an obstacle. An object is to provide a mobile robot capable of preventing recognition.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is a mobile trolley, a robot arm mounted on the mobile trolley to perform work, an area sensor arranged around the mobile trolley to detect an obstacle, and detected by the area sensor And a control means for controlling the mobile carriage or the robot arm to perform a safety ensuring operation based on the information on the obstacle, wherein the control means detects the area sensor by the robot arm. An arm position calculation unit that calculates the position of the area A2 where the robot arm intersects the detectable area A1 when passing through the possible area A1, and a range excluding the area A2 from the detectable area A1 as a detection area A detection area setting unit to be set and an obstacle map for creating an obstacle distribution map from the information acquired by the area sensor. An obstacle detection unit that detects the presence or absence of an obstacle by comparing the creation unit, the detection area set by the detection area setting unit, and the obstacle distribution map created by the obstacle map creation unit; When there is an obstacle, the system is configured by an obstacle avoidance planning unit that plans safety ensuring operations such as stopping and obstacle avoidance and transmits an avoidance command to the mobile robot.
According to a second aspect of the present invention, there is provided a movable carriage, a robot arm mounted on the movable carriage and performing work, a distance measurement with respect to an object disposed around the movable carriage, and an obstacle based on the angle. In the mobile robot, comprising: an area sensor to be detected; and a control means for controlling the mobile carriage or the robot arm to perform a safety ensuring operation based on obstacle information detected by the area sensor. The arm position calculation unit that calculates the position of the area A2 where the robot arm intersects the detectable area A1 when the robot arm passes the detectable area A1 of the area sensor; An arm speed calculation unit for calculating a speed in an area A2 that intersects the detectable area A1 of the sensor; An arm map creation unit for storing the position and speed as an arm map around the mobile robot, and an obstacle map creation unit for converting the distance and direction information acquired by the area sensor to create an obstacle distribution map; There is an obstacle detection unit that detects the presence or absence of an obstacle by comparing the arm map created by the arm map creation unit with the obstacle map created by the obstacle map creation unit In this case, it is characterized by comprising an obstacle avoidance planning unit that plans safety ensuring operations such as stopping and obstacle avoidance and transmits an avoidance command to the mobile robot.
According to a third aspect of the present invention, in the mobile robot according to the first or second aspect, the obstacle avoidance planning unit determines that the robot arm passes a detectable area of the area sensor. In this case, a command for moving the passage area is transmitted to the robot arm.
According to a fourth aspect of the present invention, in the mobile robot according to the first or second aspect, the obstacle avoidance planning unit determines that the robot arm passes a detectable area of the area sensor. In this case, a command for reducing the traveling speed is transmitted to the mobile carriage.

According to the first aspect of the present invention, in order to exclude the area around the robot arm from the detection area even when the movable carriage and the robot arm operate simultaneously and the robot arm passes through the detectable range of the area sensor. Therefore, both safety and work efficiency can be achieved without erroneously recognizing the robot arm as an obstacle.
According to the second aspect of the invention, since not only the position of the obstacle but also the speed is compared, the possibility of erroneous recognition of the robot arm and the true obstacle is reduced.
According to the invention described in claim 3, since the position of the blind spot by the robot arm changes with time, there is no stationary blind spot and the safety is further improved.
According to the fourth aspect of the present invention, deceleration when a true obstacle is detected is facilitated, and the safety of the area sensor 4 against the blind spot can be further enhanced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, description is abbreviate | omitted about the component of this invention the same as a prior art, and only a different point is demonstrated.

FIG. 1 is a top view showing the configuration of a mobile robot common to the embodiments of the present invention, FIG. 2 is a perspective view of the mobile robot of FIG. 1, and FIG. 3 shows the configuration of the control means in the first embodiment of the present invention. It is a block diagram.
In the figure, 501 is a detection area setting unit, 502 is an obstacle map creation unit, 503 is an obstacle detection unit, 504 is an obstacle avoidance planning unit, and 505 is an arm position calculation unit.
The present invention is different from the prior art as follows.
That is, the present invention is based on the condition that the mobile carriage 2 and the robot arm 3 in the mobile robot 1 operate simultaneously, and the robot arm 3 passes through the area A1 that can be detected by the area sensor 4. A region passing through the possible region A1 is indicated by A2. Basically, the passing area A2 is sequentially removed from the detectable area A1, thereby preventing erroneous detection of an obstacle.
As a feature of the control means 5, the joint angle of the robot arm 3 is acquired, and the position of each link constituting the arm is calculated by forward kinematic calculation, and the robot arm 3 can be detected by the area sensor 4. An arm position calculation unit 505 that calculates the position of the area A2 where the robot arm 3 intersects the detectable area A1 when passing through the area A1, and a range excluding the area A2 from the detectable area A1 is set as a detection area A detection area setting unit 501 that performs coordinate conversion of distance and direction information acquired by the area sensor 4 to create an obstacle distribution map, and a detection set by the detection area setting unit 501 An obstacle detection unit 503 that compares the area and the obstacle distribution map created by the obstacle map creation unit 502 to detect the presence or absence of an obstacle. In the case where there is an obstacle, it is configured by an obstacle avoidance planning unit 504 that plans a safety ensuring operation such as stopping or avoiding an obstacle and transmits an avoidance command to the robot arm 3 or the mobile carriage 2. .
FIG. 4 is a flowchart showing the processing procedure of the first embodiment. Specifically, the control means 5 executes when the mobile robot 1 operates the robot 2 while operating the mobile carriage 2. It mainly shows the procedure of processing related to the realization of the safety function (obstacle detection).
In step ST1, the control means 5 calculates the position of the robot arm 3, and in step ST2, the part A2 where the detectable area A1 and the robot arm 3 overlap is excluded from the detectable area A1, and this is used as a detection area. Next, in step ST3, it is monitored whether or not an obstacle has entered the set new detection area. If no intrusion is detected in step ST4 (No), the robot arm 3 and the moving carriage are detected. The operation of 2 is continued. When an intrusion is detected in step ST4 (Yes), stop or obstacle avoidance exercise is performed so as to avoid the obstacle. These processes are repeatedly executed at regular intervals during the operation of the mobile robot 1.
Therefore, since the first embodiment is configured as described above, even when the mobile carriage 2 and the robot arm 3 operate simultaneously and the robot arm 3 passes through the detectable range A1 of the area sensor 4, the periphery of the robot arm 3 is Therefore, it is possible to achieve both safety and work efficiency without erroneously recognizing the robot arm 3 as an obstacle.

In the first embodiment, the robot arm 3 calculates the position of the area A2 passing through the detectable area A1 of the area sensor 4 and excludes the area A2 from the detectable area A1, thereby preventing erroneous detection. In this method, there is a possibility that an obstacle existing in a straight line with the area A2 cannot be detected with respect to the area sensor. Therefore, in order to solve this problem, a means for detecting an obstacle by comparing not only the position but also the speed is necessary so that erroneous detection can be further reduced. A second embodiment will be described below as a solution.
FIG. 5 is a block diagram for explaining the configuration of the control means showing the second embodiment of the present invention.
In the figure, 506 is an arm speed calculation unit, and 507 is an arm map creation unit.
The second embodiment is different from the first embodiment in that the robot arm calculates the speed of the area A2 that passes through the detectable area A1 of the area sensor, and the position and speed of the area A2. This is the point that an arm map creation unit 507 for storing an arm map around the mobile robot 1 is provided. The obstacle map creation unit 502 performs coordinate conversion on the distance and direction information acquired from the area sensor 4 and stores the detected position and speed of the obstacle as an obstacle map around the mobile robot 1. Here, the speed information of the obstacle can be obtained by comparing the position information of the previous sample and taking a time difference. Also, the obstacle detection unit 503 compares the arm map with the obstacle map, and determines that only the obstacle that matches in position and speed is the robot arm 3 and excludes it from the detection target. . .
Therefore, since the second embodiment has the above-described configuration, it becomes a comparison object not only with respect to the position but also with respect to speed, so that the possibility of erroneous recognition of the robot arm 3 and the true obstacle is reduced.

FIG. 6 is a perspective view of a mobile robot showing a third embodiment.
In the first embodiment and the second embodiment described above, if the robot arm 3 always occupies a specific portion of the detectable area A1 of the area sensor 4, a blind spot is generated there and an obstacle cannot be detected. There was a problem. The solution is shown below.
In the third embodiment, when the arm position calculation unit 505 determines that the robot arm 3 has passed the detectable region of the area sensor 4, the obstacle avoidance planning unit 504 passes through the robot arm 3. A command for moving the area is transmitted, and as shown in FIG. 6, the robot arm 3 is swung within the detectable area to move the passing area.
According to the third embodiment, since the position of the blind spot by the robot arm 3 changes with time, there is no stationary blind spot and the safety is further improved.

In the third embodiment, when the arm position calculation unit 505 determines that the robot arm 3 has passed the detectable area of the area sensor 4, the obstacle avoidance planning unit 504 Although the example which transmits the instruction | command for moving a passage area was demonstrated, it may replace with this and you may make it reduce the traveling speed of the mobile trolley | bogie 2. FIG. By doing so, deceleration when a true obstacle is detected is facilitated, and the safety of the area sensor 4 against the blind spot can be further enhanced. However, when the robot arm 3 is detected, unlike the case where a normal obstacle is detected, it is not necessary to perform an obstacle avoidance exercise.
In this embodiment, the area sensor is a distance measurement type using a laser described in Patent Document 1, for example, but a vision sensor based on image recognition may be used instead. "

  The present invention presents a measure for preventing the robot arm from being erroneously detected as an obstacle, but can be applied to an object held by the robot arm in exactly the same manner. Further, the present invention can be applied not only to a robot arm but also to an application for preventing erroneous detection of an effector mounted on a moving carriage and operating.

The top view which shows the structure of the mobile robot common to the Example of this invention 1 is a perspective view of the mobile robot of FIG. The block diagram which shows the structure of the control means in 1st Example of this invention. The flowchart which shows the procedure of the process of 1st Example. The block diagram which shows the structure of the control means in 2nd Example of this invention. The perspective view of the mobile robot which shows 3rd Example of this invention. Top view for explaining the configuration of a mobile robot showing the prior art The flowchart which shows the procedure of the process in a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile robot 2 Mobile cart 3 Robot arm 4 Area sensor 5 Control means 6 Fixed equipment 501 Detection area setting part 502 Obstacle map creation part 503 Obstacle detection part 504 Obstacle avoidance plan part 505 Arm position detection part 506 Arm speed detection part 507 Arm map creation part

Claims (4)

Mobile cart (2),
A robot arm (3) mounted on the movable carriage (2) for working;
An area sensor (4) arranged around the mobile carriage (2) for detecting obstacles;
Movement provided with control means (5) for controlling the mobile carriage (2) or the robot arm (3) to perform a safety ensuring operation based on the obstacle information detected by the area sensor (4) In robot (1),
The control means (5)
When the robot arm (3) passes the detectable area (A1) of the area sensor (4), the position of the area (A2) where the robot arm (3) intersects the detectable area (A1) is calculated. An arm position calculation unit (505) to perform,
A detection area setting unit (501) for setting a range obtained by excluding the area (A2) from the detectable area (A1) as a detection area;
An obstacle map creating unit (502) for creating an obstacle distribution map from the information acquired by the area sensor (4);
An obstacle detection unit (503) that detects the presence or absence of an obstacle by comparing the detection area set by the detection area setting unit (501) and the obstacle distribution map created by the obstacle map creation unit (502). )When,
It is characterized by comprising an obstacle avoidance planning unit (504) that plans safety ensuring operations such as stopping and obstacle avoidance when there are obstacles and sends an avoidance command to the mobile robot (1). Mobile robot to be. Mobile cart (2),
A robot arm (3) mounted on the movable carriage (2) for working;
An area sensor (4) arranged around the mobile carriage (2) for detecting obstacles;
Movement provided with control means (5) for controlling the mobile carriage (2) or the robot arm (3) to perform a safety ensuring operation based on the obstacle information detected by the area sensor (4) In robot (1),
The control means (5)
When the robot arm (3) passes the detectable area (A1) of the area sensor (4), the position of the area (A2) where the robot arm (3) intersects the detectable area (A1) is calculated. An arm position calculation unit (505) to perform,
An arm speed calculation unit (506) for calculating a speed in an area (A2) where the robot arm (3) intersects a detectable area (A1) of the area sensor (4);
An arm map creation unit (507) for storing the position and speed of the area (A2) as an arm map around the mobile robot (1);
An obstacle map creating unit (502) for creating an obstacle distribution map from the information acquired by the area sensor (4);
An obstacle detection unit (503) that detects the presence or absence of an obstacle by comparing the arm map created by the arm map creation unit (507) with the obstacle map created by the obstacle map creation unit (502). )When,
It is characterized by comprising an obstacle avoidance planning unit (504) that plans safety ensuring operations such as stopping and obstacle avoidance when there are obstacles and sends an avoidance command to the mobile robot (1). Mobile robot to be. When the obstacle avoidance planning unit (504) determines that the robot arm (3) has passed the detectable area of the area sensor (4), the obstacle avoidance planning unit (504) The mobile robot according to claim 1, wherein a command for moving the robot is transmitted.   When the obstacle avoidance planning unit (504) determines that the robot arm (3) has passed the detectable region of the area sensor (4), the obstacle avoidance planning unit (504) sets the traveling speed to the moving carriage (2). The mobile robot according to claim 1, wherein a command for reducing is transmitted.

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