JPH02311909A - Mobile robot - Google Patents

Abstract

PURPOSE:To attain the simultaneous bidirectional operations of a mobile robot and also to avoid the obstacles for the running robot by including the driving offset data into the map information and providing a driving control part which controls the drive of the robot based on the offset data. CONSTITUTION:A track correction part 15 counts the pulse signals received from the left and right encoders 12a and 12b to decide a driving distance and the driving speed of a mobile robot and also decides a rotational angle from the difference between the right and left pulse signals. Then the driving distance, the driving speed, and the rotational angle calculated from the pulse signals are compared with the output data given from an environment recognizing part 14 for the production of the speed feedback signals Vxf and Vyf and the feedback signal thetaf of the rotational angle. So that the robot is driven based on the contents of a scene table SCT of a map part 5. Under such conditions, the component elements 6 - 15 form a driving part 20 and a mobile robot constitute the part 20 and a command part 3. Consequently, the single-side pass control, etc., can be applied to the optional section of a driving path. Thus the robot can be smoothly operated.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention is applicable to offset driving, that is, based on a command, driving on the right (or left), driving on the right (or left)
It relates to a mobile robot that can move around, etc.

"Prior Art" In recent years, with the development of FA (factory automation), various mobile robot systems consisting of a plurality of mobile robots and a control station that controls these mobile robots have been developed and put into practical use.

FIG. 7 shows a schematic configuration of this mobile robot system. In this figure, l is a control station, 2 (2-1 to
2-10) is a mobile robot that has wheels on its running section. The control station 1 instructs each mobile robot 2, wirelessly or by wire, about the destination and the work to be performed at the destination. The mobile robot 2 receives instructions from the control station 1, looks at the map information, automatically travels to the instructed location, and
Work as instructed at the location, and when the work is completed, wait for the next instruction.

``Problems to be Solved by the Invention'' By the way, in the conventional mobile robot system mentioned above, 1. If a plurality of mobile robots 2 are allowed to travel simultaneously on a predetermined section of travel path, there is a risk of a head-on collision. Ta.

In order to avoid this, the other mobile robots 2 had to be placed in a standby state until the - mobile robot 2 passes. This has been an impediment to improving the operating efficiency of the mobile robot 2 and, in turn, the work efficiency.

Further, after the travel route has been set, there may be a situation where it is desired to shift a predetermined section of the travel route slightly to the right (or left) due to the introduction and installation of new equipment. Changing the driving route in this way requires major revisions to the map, which is complicated.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a mobile robot that can comply with one-way traffic regulations, etc., in order to achieve smooth operation of the mobile robot.

A further object of the present invention is to provide a mobile robot that can perform offset travel in order to eliminate the complicated task of changing the travel route.

"Means for Solving the Problems" In order to solve the above problems, the present invention includes a map memory that stores map information, searches for a route by looking at the map information in the map memory, and searches for routes. In a mobile robot that automatically travels along a route, the map information includes travel offset data representing a travel offset value from a travel reference line for each travel element road and for each travel direction, and It is characterized by being equipped with a travel control section that controls travel according to data.

"Operation" In this configuration, the mobile robot automatically travels toward the destination along the searched route.

At this time, the vehicle also looks at the travel offset data in the map information and drives accordingly.

According to this configuration, it is possible to restrict one-way traffic on any section of the travel route, making it possible to pass in both directions and avoid obstacles, making it possible for mobile robots to move more smoothly. operation can be achieved.

It is also possible to avoid the complicated work of changing the running or route.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the mobile robot 2. As shown in FIG. Note that the general configuration of the mobile robot system of this example is the same as that of the above-mentioned conventional example (FIG. 7).

In FIG. 1, 3 is a command section, and this command section 3 is
When a destination node designated by radio from the control station 1 that supervises a plurality of mobile robots 2 is supplied via the communication device 4, a map stored in the map unit 5 (described later) The travel command G(x, y, ...) (described later) are sequentially created and output. Here, the node refers to a driving state change point and a driving state monitoring point provided on a travel road, such as a waiting point (station), a stopping point, a branch point, an intersection, a work point, etc. Reference numeral 6 denotes a command receiving section that receives running commands G (X r Y r . . . ) sequentially supplied from the command section 3, and is constituted by a FIFO (first in, first out) buffer.

The command receiving unit 6 receives the sent running command G (
X + )'r...) is supplied to the command interpretation section 7 and the trajectory correction section 15. The command interpreting unit 7 interprets a series of running commands G (X * Y +...), . . . to create a running pattern for the mobile robot 2, and issues a servo command as a running butterfly signal "jlvl+θ". The servo command creation unit 8 supplies the travel pattern signals V, . V.

θ is read every predetermined sampling period, and these are used as a feedback signal V*f+vVf+θ, which will be described later.

The deviation signal Δv8. ΔvF+Δθ is calculated and these signals are converted into analog signals and then supplied to the servo control section 9. As a result, the servo control unit 9 adjusts the deviation signal ΔVII+ΔvFlΔθ to zero by 1,
The left and right motors 10a, 10b are drive-controlled to rotate the left and right wheels 11a, llb. Motor 10a, fob
The number of rotations is converted into electric pulses by left and right encoders 12a and 12b connected to the rotation shafts of motors lOa and 10b, respectively, and supplied to the trajectory correction unit 15. Reference numeral 13 denotes an ultrasonic distance measurement unit that actually measures the distance from the mobile robot to the left and right walls using ultrasonic waves. The ultrasonic ranging section 13 drives the ultrasonic transmitters 13a provided on the left and right to emit ultrasonic waves toward the left and right walls, and transmits the reflected waves from the left and right walls to the left and right ultrasonic receivers 13b. The distances to the left and right walls are measured based on the elapsed time. This measurement result is supplied to the environment recognition section 14. The environment recognition section 14 transfers the measurement results to the trajectory correction section 15, detects the presence or absence of walls and changing points (edges), and also supplies the detection results to the trajectory correction section I5. Orbit correction part 1
5 counts the pulse signals sent from the left and right encoders 12a and 12b to determine the travel distance and travel speed, and also determines the rotation angle from the difference between the left and right pulse signals. Then, the trajectory correction unit 15 outputs the travel distance, travel speed, rotation angle calculated from the pulse signal and the output from the environment recognition unit 14 in order to travel based on the contents of the scene table SCT (described later) of the map unit 5. A speed feedback signal Vxr+vyes and a rotation angle feedback signal θC are generated by comparing the data. The above is the configuration of this embodiment, and the above-mentioned components 6 to 15 are the running part 20.
The command section 3 and the traveling section 20 constitute the mobile robot 2.

◇Map (Information) Next, the map (information) stored in the map section 5 will be described in detail.

The map is composed of a node number table NDT, a node connection information table NWT, and a scene table SCT.

(A) Node number table NDT (Fig. 2) As shown in Fig. 2, registered node numbers are stored in the node number table NDT in the order of registration.

(B Network Information Table NWT (Fig. 3) As shown in Fig. 3, the network information table NWT stores network information of registered nodes in association with node numbers.Network Information Table NWT
is composed of the columns shown below.

(1) Mate's World Coordinates Column This column describes the position data of the node in question, which is displayed using the XY coordinate system.

(2) Work point world coordinate column This column describes the position data of the work point displayed in the XY coordinate system. However, if no work point is connected to the node, it will not be described.

(3) Connected Node Number Column This column stores the numbers of other nodes connected to the node in question. In this example, the maximum number of nodes connected to one node is four. Therefore, a maximum of four node numbers are stored.

(4) Scene Table Number Column This column indicates in which scene table SCT a series of scenes (scenes) between nodes corresponding to the connected node number is stored.

(5) Scene Offset Column This column stores a scene pointer (address) indicating from which byte in the scene table SCT a series of scenes between nodes corresponding to the connected node number begins.

The above-described node number table NDT and network information table NWT are referred to when the command unit 3 searches for a route and creates a travel command.

(C) Scene table SCT As shown in FIG.
This table stores a series of scenes (wall conditions) and running conditions from one node to the next node in association with scene pointers (contents of the scene offset field).

The scene table SCT is composed of the columns shown below.

(1) Starting point number field This column stores the number of the starting point node.

(2) End node number column This column stores the number of the end node. Note that the starting point mate and the ending node are simply two adjacent nodes, one of which is referred to as the starting point node and the other as the ending node.

(3) Straight-line distance between nodes column This column stores the value of the straight-line distance from the start point node to the end point node determined from the position coordinates.

(4) Measured distance between nodes column This column stores the measured value of the distance from the start point node to the end point node. However, there is a value only if the node is not a straight line, and if it is a straight line, 0 is stored.

(5) Forward Travel Offset Column This column stores the travel offset value from the reference line when traveling from the starting point mate to the ending node. here,
The reference line generally refers to a straight line connecting a starting point node and an ending point mate (described later). When the above travel offset value is positive, it instructs to travel offset to the left from the reference line (with respect to the direction of travel), and when the travel offset value is negative, it instructs to travel offset to the left from the reference line (with respect to the direction of travel). Instructs the vehicle to drive offset to the right. For example, when the travel offset value is +d (positive), it means that the vehicle should travel a distance d to the left from the reference line (see FIG. 5). On the other hand, -d (negative) means to drive a distance d to the right from the reference line. In this manner, by arbitrarily specifying the travel offset value, it is possible to specify driving on the right, driving on the left, driving on the right edge, or driving on the left edge.

(6) Reverse Travel Offset Column This column stores the travel offset value from the reference line when traveling from the end point node to the start point node. The reference line and travel offset value are as explained in the forward direction travel offset column.

(7) Speed limit column This column stores the maximum speed limit between the nodes.

(8) Left Scene Command Column This column describes the state of the left wall. If there is a wall within the maximum measurement distance of the ultrasonic distance measuring unit 13, the "distance to the wall" and the length of the wall are described. The above-mentioned reference line is specified by the above-mentioned "distance to the wall". In other words, the distance between the left wall and the left side of the mobile robot is
If the robot 2 is kept within the distance from the wall, it means that the mobile robot 2 is positioned on the reference line. Here, if there are changing points (edges) on the wall, set the "distance to the wall" for each changing point on the wall.
and the length to the wall. In addition, the ultrasonic ranging section 1
3. When there is no wall within the maximum measurement distance, that is, in an open state, the distance of the oven section is described.

(9) Right scene command field This column describes the state up to the right wall.

If you replace the left with the right, the description is the same as described in the left scene command column above.

The scene table SCT is referred to by the traveling section 20 when the mobile robot 2 travels.

◇ Travel Command Next, the travel command created by the command unit 3 will be described in detail.

The running command includes a Go command, a WAIT command, and the like.

(1) GO command The Go command is a command that provides information for traveling on a continuous route.

The Go command is written in the following format.

<G O>= G O (x, y, v, θ, p
+ n) Here, X is a variable that specifies the traveling distance ('mm) in the X-axis direction shown in Fig. 5, and when X is positive, the forward distance of the mobile robot 2 is specified, and X is If negative, the backward distance is specified. y is a variable that specifies the traveling distance (mm) in the Y-axis direction shown in Fig. 5. When y is positive, the leftward movement distance of the mobile robot 2 is specified, and when it is negative, the rightward movement distance is specified. It is specified. Further, V is a variable indicating the composite speed of the X-axis (forward/reverse) speed component and the Y-axis (left/right) speed component.

θ is a variable indicating the rotation angle (rad) of the mobile robot 2 at the time of command execution (when θ is counterclockwise, it is assumed to be a positive direction). p is the scene pointer mentioned above. Further, n specifies the mate number reached after the command is executed.

(2) WAIT Command This command is a command that instructs the temporary stop of the running operation, the stopping method, the brake state after stopping, the servo power state after stopping, and also provides information such as the reason for stopping.

The W^IT command is written in the following format.

<WAIT>=WAIT(f, b, s, r
) Here, f is a parameter that specifies the stopping method.
When f is "0", slow deceleration and stop are performed, and f is "0".
1" means a sudden stop. b is a parameter that specifies the brake state after stopping; when b is "0" it means a state in which the brake is not applied, and when it is "1" it means a state in which the brake is applied. S is a parameter that specifies the servo power state after stopping, and S is "0".
When , it means the servo power is off, and when it is NJ, it means the servo power is on. r is a parameter indicating the reason for stopping; when r is "O", it is a normal pause state; when r is "1", it is a stopped state after work positioning;
” specifies the stop state after returning to the station, and “3” specifies the stop state after job completion.

◇Example of Offset Travel Next, with reference to FIG. 5, a case in which the mobile robot 2 performs offset travel, for example, driving on the left side, will be described.

When the trajectory correction unit 15 receives the scene pointer p, which is a component of the GO command, from the command receiving unit 6, it reads out the scene specified by the supplied scene pointer p from the scene table SCT of the map unit 5. Assume that as a result of looking at the "distance to the wall" in the left scene command field and the right scene command field, it is recognized that the "distance to the wall" is both D. Next, suppose that you look at the travel offset column (if you are traveling in the forward direction, look at the forward offset column) and recognize that the travel offset value is +d. As a result, the trajectory correction section 1
5 recognizes that he must drive a distance d to the left from the reference line. That is, from the right wall (D+
d) Recognize that you must drive on a line that is far away ((D-d) away from the left wall) (see Figure 5)
. Then, in order for the mobile robot 2 to travel on a line that is (D+d) away from the right wall, a rotation angle feedback signal θ is sent.
, and sends it to the servo command creation section 8.

Next, the operation of the mobile robot described above will be explained with reference to FIG.

First, it is assumed that the mobile robot 2 is waiting at node n0, facing toward node n1. here,
When node n is specified as the destination from control station l,
Upon receiving this instruction, the command unit 3 sends the map (information) of the map unit 5
Based on, the shortest path from node n0 to n is searched, and n0→n,→n.

→n, →n, routes are determined. The search methods applied here include the well-known vertical search method and horizontal search method. When the route is determined in this way, the command unit 3 creates the following series of travel commands as commands to be transferred to the travel unit 20.

<c o , )-c o <x O1+O+ v 01
+0+ p a+, n +)<Go,>=GO(X
,,,O,V,,,-1,57QB,p 14
1 n 4) <co 3>= co (x 45
101 V 46. +1.57081 p 4%1 n
s) <GO+>= GO(X 87+01 V
5? , -1,5708,1)6? , n 7) <W
AIT>= WAIT (0, l, 0.0) The first run command <GO,> is the current node n.

Without changing direction, the speed is V. , which means that moving forward by XOI will reach 7-do n. Furthermore, the scene (scene of the surrounding walls) that may be seen while traveling from node n0 to node n1 is p of the scene table SCT.

This shows that it is stored at address l. Second
The th running command <GO,> is from node n1 to θ+
a = -1,5708 rad rotated direction, that is, 90 degrees clockwise, speed "+4
This means that if you move forward by XI4, you will reach 7-do n4. Further, it is shown that the scene of the surrounding wall that may be seen while traveling from node n1 to node p na is stored at address p14. The third running command <G03> is from node n4 to θ, , = +l
, This means that if the node moves forward by X4S at a speed of V□ in a direction rotated by 5708 rad, that is, in a direction turned 90 degrees counterclockwise, it will reach node n5. In addition, the scene that may be seen (the scene of the surrounding walls) while traveling from node n4 to node 7-do n is the scene table SC.
p of T. This shows that it is stored at the address. The fourth run command <G O,> is at node n5
In the direction rotated by θs7=-1,5708 rad from
At and XS? This means that moving forward will reach node n7. Further, it is shown that the scene of the surrounding wall that may be seen while traveling from node n to node n7 is stored at the address of pI7. Further, the fifth running command <WAIT> instructs a temporary stop of the operation (slow deceleration and stop). Then, after stopping, the driver is instructed to apply the brakes and turn off the servo power supply.

When such a running command is received by the command receiving unit 6, as described above, the command receiving unit 6 transfers the received running command to the command interpreting unit 7, and also transfers the received running command to the command interpreting unit 7.
The trajectory correction unit 15 adjusts the scene pointer p, which is a component of the command.
Transfer to. The command interpreter 7 interprets the supplied travel command, creates a travel pattern (speed pattern, rotation pattern), and sends it to the servo command creator 8.

On the other hand, when the trajectory correction unit 15 receives the scene pointer, it reads out the scene specified by the scene pointer p from the scene table SCT of the map unit 5, and instructs the environment recognition unit 15 to follow the instructions and contents of the scene. The output data from the encoders 12a and 12b are compared with the output pulses from the encoders 12a and 12b to create feedback signals of speed and rotation angle.

In this way, when the travel offset value specified by the scene pointer po+ is -dot, the mobile robot 2 moves from node n0 to node n, as shown in FIG.
When the travel offset value specified by the scene pointer p14 is 10d14, the vehicle travels on the left side between node n and node n4, and the travel offset value specified by the scene pointer p45. is -dSt
In this case, nodes n4 to 71d n% run on the right side, and the scene pointer pS? When the traveling offset value specified by is O, from node n to node n7
During this period, the vehicle will be driven in the center of the driving route (reference line).

In this way, according to the above configuration, it is possible to run offset with respect to the reference travel path, so that a mobile robot that travels in the forward direction and a mobile robot that travels in the reverse direction simultaneously exist with respect to any travel path. Even in this case, collisions can be avoided.

In addition, in the above-mentioned embodiment, the offset value described in the travel offset column is constant between the nodes (for example, between node n and node n6), but the offset value is not limited to this. Alternatively, the distance between nodes n0 and n1 may be divided into predetermined sections, and different offset values may be set for each section. If you do this, /-do n. If obstacles exist irregularly between node n1 and node n1, it is possible to avoid the obstacles and travel in a zigzag pattern.

"Effects of the Invention" As explained above, the present invention provides that the map information includes travel offset data representing a travel offset value from a travel reference line for each travel element road and for each travel direction, and Since it is equipped with a travel control unit that controls travel according to the travel offset data, it is possible to drive on the right or left side, on the right edge, or on the left edge of the road in any section according to what the travel offset data indicates. It can be carried out. Therefore, simultaneous two-way traffic, obstacle avoidance, etc. are possible, and even smoother operation of the mobile robot can be achieved.

Further, the complicated work of changing the driving route can be avoided.

[Brief Description of the Drawings] Figure 1 is a block diagram showing the electrical configuration of a mobile robot according to an embodiment of the present invention, and Figure 2 shows the configuration of a node number table stored in the map section of the mobile robot. FIG. 3 is a conceptual diagram showing the structure of a network information table stored in the map section, FIG. 4 is a conceptual diagram showing the structure of a scene table stored in the map section,
Fig. 5 is an explanatory diagram for explaining offset travel of the mobile robot, Fig. 6 is an explanatory diagram for explaining the operation of the mobile robot, and Fig. 7 is a mobile robot system to which the mobile robot is applied. FIG. 3 is a diagram showing the configuration. ■・・・Control station, 2,2~1~2-10...
...Mobile robot, 3...Command section, 5...
...Map section, NDT...Node number table,
NWT・・・Network information table, SCT
・・・・・・Number table, 6・e・・・・Command reception section, 7 ”・・・・Command interpretation section, 8...
・Servo command creation section, 9... Servo control section, 1
2a, 12b... Encoder, 13...
・Ultrasonic ranging section, 14...Environment recognition section, 15.
...Track correction section, 20...Travel section, no.
on l+n! +I'l'l+na+nll+n@nma.・・・−Node. Figure 7■ w--h, -111----------Go--Figure 3 Ne・, Totsu-ri 1) ^ In a bottle, Arnaud 14-'3n's Ne. , twerk emotional body heat θtsu

Claims (1)

[Scope of Claims] A mobile robot having a map memory for storing map information, searching for a route by looking at the map information in the map memory, and automatically traveling along the searched route, comprising: is characterized by comprising a travel control unit that includes travel offset data representing a travel offset value from a travel reference line for each travel element road and for each travel direction, and that controls travel in accordance with the travel offset data. A mobile robot.