JP2020004095A - Autonomous mobile body controller and autonomous mobile body - Google Patents

Abstract

To create a mobile path by considering the movement of a mobile obstacle at a collision prediction point.SOLUTION: An AGC controller can three-dimensionally describe an obstacle area in a three-dimensional space including a time base (S5) and searches a path for avoiding an obstacle area (S6); therefore, in consideration of the movement of a mobile obstacle at a collision prediction point, a mobile path for reaching a target position at the shortest time can be created. Thus, the time for reaching the target position can be shortened without having an influence of the movement of the mobile obstacle at the collision prediction point.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an autonomous mobile body control device and an autonomous mobile body.

  In an environment where an autonomous mobile device searches for a route to a target position and generates a moving route, in an environment where there are only fixed obstacles around, an SLAM (Simultaneous Localization and Mapping) that simultaneously performs self-location estimation and environment mapping is used. Technology may be used.

JP 2008-152599 A

However, in an environment where people, forklifts, and the like move as in a factory, it is necessary to detect a moving obstacle located around the autonomous mobile body and search for a route to avoid it.
In Patent Literature 1, a rough collision prediction point is calculated from the current speed and acceleration of an autonomous moving object and a moving obstacle at the time of a route search, and a moving obstacle may be located based on the collision prediction point. It has been proposed to set a certain obstacle region, search for a route avoiding the obstacle region, and generate a moving route. In this case, since the obstacle region set at the time of the route search is two-dimensional (plane), a route that avoids the obstacle region set in the two-dimensional space is searched.

  However, since the moving obstacle at the collision prediction point is usually actually moving, if the moving path is generated in the direction of movement of the obstacle area at the collision prediction point, the collision prediction point is The passing obstacle moves toward the autonomous moving body. For this reason, depending on the movement of the moving obstacle at the collision prediction point, it is assumed that the moving obstacle hinders the autonomous moving body.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an autonomous moving object control device and an autonomous moving object that can generate a moving path by considering the movement of a moving obstacle at a collision prediction point. Is to do.

  According to the first aspect of the present invention, when the obstacle detection unit (8) detects a moving obstacle located around the autonomous mobile unit (1), the obstacle state calculation unit (13) sets the obstacle detection unit to The movement information including the position and time of the detected moving obstacle is calculated. Then, since the obstacle area calculation unit (14) calculates the moving position of the moving obstacle at each predetermined continuous time as the obstacle area based on the movement information, the route planning unit (15) calculates the continuous predetermined time. The movement path of the autonomous mobile body is generated using the obstacle area constituted by Then, the movement control unit (16) controls the movement of the autonomous mobile body along the movement route. This makes it possible to avoid being affected by the movement of the moving obstacle at the collision prediction point.

Functional block diagram showing the configuration of the control device in the first embodiment Perspective view of unmanned transport cart Diagram for explaining a conventional moving route search method Diagram explaining the method of searching for a moving route The figure which shows the moving route which avoids one obstacle area typically A diagram schematically showing a moving route that avoids one obstacle area in the related art Flow chart showing a method of searching for a moving route Diagram showing travel routes to avoid multiple obstacle areas Functional block diagram showing a configuration of a control device according to a second embodiment. Diagram showing passable area FIG. 14 is a diagram illustrating a route generation range according to the third embodiment. FIG. 14 is a diagram illustrating a moving obstacle that is not set as an obstacle area according to the fourth embodiment.

Hereinafter, a plurality of embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding parts are provided with the same reference signs.
(1st Embodiment)
The first embodiment will be described with reference to FIGS.
An automatic guided cart (hereinafter, referred to as AGC) 1 (corresponding to an autonomous mobile body) 1 (corresponding to an autonomous moving body) shown in FIG. 2 is used in a facility such as a factory, for example, and is a SLAM that simultaneously estimates its own position and creates an environment map. By using the technique described above, the vehicle autonomously moves from the current position to the target position.

  SLAM is suitable for an environment where objects with fixed positions are arranged. Since the factory where AGC1 is used is provided with fixed walls, columns, fixed facilities, etc., the factory where AGC1 is used is an environment suitable for SLAM, and it is possible to accurately estimate its own position and map its environment. Creation can be done.

The AGC 1 is equipped with an IMU (Inertial Measurement Unit) (not shown) including a three-axis gyro sensor and a three-axis acceleration sensor as a configuration for estimating its own position and creating an environment map. Recognizable as information.
Hereinafter, description of SLAM will be omitted, and only the configuration related to the present invention will be described.

  The AGC 1 includes a traveling unit 2 and a control device 3 (corresponding to an autonomous mobile body control device), and can mount a work module (not shown). The work module is responsible for transferring, changing the packaging style, and the like, and various types such as a lifting type, a robot type, a conveyor type, an index type, and a trolley type are prepared. The user can use the AGC 1 for various purposes by appropriately selecting a desired module and mounting the module on the traveling unit 2.

  The traveling unit 2 is configured by mounting a wheel 5 and a motor 6 for driving the wheel 5 on a frame 4, and autonomously moves to a target position set in a passage in a factory where the AGC 1 is used. It can run. The wheel 5 is a Mecanum wheel, and is configured by providing a plurality of barrel-shaped rollers 7 on the circumference of the wheel 5. The roller 7 is mounted so as to be freely rotatable with its axis inclined at 45 degrees with respect to the axis of the wheel 5.

  The driving force of each motor 6 is transmitted to the corresponding wheel 5, and each wheel 5 can be independently rotated forward and backward by the motor 6. The traveling unit 2 is capable of freely traveling in all directions as well as moving forward, backward, and turning by combining the rotation directions of the wheels 5.

As shown in FIG. 1, the control device 3 includes an obstacle detection unit 8, a control unit 9, and an operation display unit 10.
The obstacle detection unit 8 includes the laser radar 11 and the ultrasonic sonar 12 shown in FIG. 2, and detects an obstacle located around the AGC 1 (frame 4). The laser radar 11 has a predetermined angle in the horizontal direction with respect to the front (for example, 270 degrees) set as a detection area, and detects an obstacle located in front of the AGC 1. The ultrasonic sonars 12 are respectively provided at the rear corners of the frame 4 and detect an obstacle located behind the AGC 1. A monocular camera or a stereo camera may be employed as the obstacle detection unit 8.

  The control unit 9 is mainly configured by a microcomputer having, for example, a CPU, a ROM, a RAM, and the like, and includes an obstacle state calculation unit 13, an obstacle area calculation unit 14, a route planning unit 15, and a movement control unit 16. ing. These units 13 to 16 are realized as software by the CPU of the control unit 9 executing a program stored in a ROM or the like. These units 13 to 16 may be configured to be realized by hardware.

  The control unit 9 calculates the moving position and the elapsed time of the moving obstacle by the obstacle state calculating unit 13 with respect to the moving obstacle detected by the obstacle detecting unit 8, and calculates the moving position and the elapsed time based on the calculated moving position and the elapsed time. First, the speed / acceleration information of the moving obstacle is calculated. As a method of calculating the speed / acceleration information, for example, a method of calculating the speed from the current position and the position one step before, or the time taken between them, or another method may be used.

  The operation display unit 10 can display the state of the AGC 1, the state of the work module, and the like, and can display the operation state of the AGC 1, an image representing a recognized environment, the type of the work module, an abnormality related to the AGC 1, a warning, and the like. it can. The operation display unit 10 can be operated by the user, and the control content of the control unit 9 can be changed according to the operation.

  By the way, in the conventional route search, when a moving obstacle located around is detected during the route search, an obstacle region is set in a two-dimensional space corresponding to the moving obstacle, and the obstacle region is avoided. By searching for a route, a moving route that can reach the target position in the shortest time is generated.

  That is, as shown in FIG. 3, first, at t = T0, the corresponding obstacle areas A1 to C1 are set based on the predicted collision points of the moving obstacles A to C, and the obstacle areas A1 to C1 are set. A moving route is generated by searching for a route that can reach the target position in the shortest time while avoiding it. Note that the collision prediction point is the center of each of the obstacle areas A1 to C1.

  When the vehicle reaches the obstacle area A1 (t = T1), obstacle areas B1 and C1 corresponding to the moving obstacles B and C are set, and the obstacle area B1 and C1 are avoided to reach the target position in the shortest time. Search for possible travel routes and generate travel routes. By repeating such operations in order, a movement route to the target position is generated.

  Here, since the obstacle region is represented in two dimensions (a plane), a route is searched so as to avoid a stationary obstacle region in the two-dimensional space. For this reason, no consideration is given to the effect of the movement of the moving obstacle at the collision prediction point, and the moving obstacle affects the generated moving path depending on the movement of the moving obstacle at the collision prediction point. A case can be assumed. For example, when a moving path is generated in the moving direction of the moving obstacle at the collision prediction point, the possibility of being affected by the movement of the moving obstacle at the collision prediction point increases.

  Under such circumstances, in the present embodiment, in a situation where the path planning of the AGC 1 is performed in an environment in which a moving obstacle such as a person or a forklift exists, the moving position of the moving obstacle at every continuous predetermined time period Is calculated as a dynamic obstacle area, and the moving path of the AGC 1 is generated using the obstacle area formed by the continuous predetermined time.

  That is, as shown in FIG. 4, the obstacle area calculation unit 14 connects the continuous obstacle areas An, Bn, and Cn (n is a positive natural number) at predetermined time intervals to thereby form an obstacle area Ax in a three-dimensional space. Is calculated, and the route planning unit 15 searches for a route that can reach the target position in the shortest time while avoiding an obstacle region in the three-dimensional space, thereby generating a movement route. The moving route is generated by connecting a plurality of nodes set between the current position and the target position. Then, the movement control unit 16 controls the movement of the AGC 1 along the movement route. In FIG. 4, the obstacle regions are separated from each other with a longer time interval for easy understanding, but each obstacle region is actually continuous.

  More specifically, as shown in FIG. 5, an obstacle region corresponding to the moving obstacle detected at the time of the search is three-dimensionally described in a three-dimensional space (x, y, t), and the obstacle region is represented. Search for a route that can reach the target position in the shortest time while avoiding. That is, a continuous moving position at predetermined time intervals is calculated as a three-dimensional obstacle region based on the calculated moving information such as the speed and acceleration of the moving obstacle. In this case, for example, when the error due to the moving time is not considered, the obstacle area is represented by the following equation, and the trajectory of the moving obstacle is calculated from the calculated movement information such as the speed and the acceleration, and the trajectory is centered. Is calculated.

  Now, as shown in FIG. 5, when an obstacle region that does not consider an error due to the moving time of a moving obstacle is depicted in a three-dimensional space, a cylinder is depicted three-dimensionally. In this case, the inclination direction of the cylinder indicates the moving direction of the moving obstacle, and the inclination angle indicates the magnitude of the moving speed of the moving obstacle.

  Here, when the conventional obstacle region is described in a three-dimensional space, a vertical cylinder with no inclination can be described as shown in FIG. Here, when searching for a route that avoids the cylinder shown in FIG. 6 by the conventional avoidance method, since the collision prediction point is located at the center of the cylinder, the moving route that goes around the inclined direction side of the cylinder is considered. (Shown by a broken line in the figure) and a movement route (shown by a solid line in the figure) that goes around the side opposite to the inclination direction of the cylinder can be assumed. In this case, since the routes that go around on either side of the cylinder have the same distance, the arrival time to the target position is also the same.

On the other hand, since the cylinder shown in FIG. 5 is inclined in the moving direction of the moving obstacle, the path (shown by a broken line in the figure) that goes around the inclined direction of the cylinder goes around the inclined direction side of the cylinder inclined forward. The distance around the front side of the cylinder is longer than the distance indicated by the broken line in FIG. On the other hand, the path (shown by a solid line in the figure) that goes around the opposite side to the direction of inclination of the cylinder goes around the opposite side to the direction of inclination of the cylinder that is inclined forward, and the distance that goes around the cylinder is shown by the solid line in FIG. It is shorter than the distance shown.
5 and 6, it is assumed that the AGC 1 having a size of zero moves toward the target position at a constant speed, and the AGC 1 is described as being movable along the outer peripheral surface of the cylinder.

  The control device 3 performs path planning in a three-dimensional space so as to avoid the obstacle region set as described above. As a route planning technique, as shown in FIG. 7, first, a three-dimensional space is set (S1), and it is determined whether a moving obstacle is detected (S2). If a moving obstacle is not detected (S2: NO), a route search is performed in a three-dimensional space (S6), and a moving route is generated (S7), and then the robot moves along the moving route (S8).

  On the other hand, when a moving obstacle is detected (S2: YES), speed information and acceleration information are calculated by acquiring movement information on the position and time of the moving obstacle (S3), and obstacles are calculated based on the information. An object area is calculated (S4), and the obstacle area is described in a three-dimensional space (S5).

  The above operation is executed each time a moving obstacle is detected, and when the drawing of the obstacle areas corresponding to all the moving obstacles in the three-dimensional space is completed, the target position in which the arrival time is specified in the three-dimensional space is also set. By setting, for example, using a route search method such as RRT (Rapidly-exploring Random Tree), PRM (Probabilistic Roadmap Method), A * (A-star), etc., it is possible to avoid an obstacle area in a three-dimensional space and to minimize the distance to a target position. To search for a route that can be reached (S6). Then, after the movement route is generated (S7), the robot moves along the movement route (S8).

  Although not shown in FIG. 7, if the route cannot be searched for the set initial target time, the target position is set for a more advanced time and the route search is executed again. If a route for the arrival time and position cannot be searched, a target position is set for a more advanced time, and the route search is executed again. Such an operation is repeated until a movement route for the arrival time and the position can be generated.

  By the way, in an actual route search, a plurality of moving obstacles A to C may be located around the AGC 1 as shown in FIG. 8, and in such a case, a plurality of obstacle areas Ax to Cx are set. A moving path is set in a three-dimensional space, and avoids the obstacle regions Ax to Cx to generate a moving route that reaches the target position in the shortest time.

  When setting an obstacle area, it is effective to set a simple error so that a circle around the locus of the moving obstacle includes a predetermined error. In this case, the moving obstacle has a conical shape represented by the following equation. An example of the error is an error in the movement position due to the elapse of the movement time until the collision prediction point is reached, and an error proportional to time is included in a circle centered on the trajectory. The obstacle region may be set by a method other than this method, such as a method of statistically calculating the position variation, as in the existing technology, or a method other than the method described above.

  As described above, even when a plurality of moving obstacles are located around the AGC 1, the control device 3 three-dimensionally describes an obstacle region corresponding to the moving obstacles in a three-dimensional space, and In this way, it is possible to generate a movement route that can reach the target position in the shortest time while avoiding the obstacle area.

According to such an embodiment, the following effects can be obtained.
The control device 3 of the AGC 1 three-dimensionally describes the obstacle region in a three-dimensional space including the time axis and searches for a route that avoids the obstacle region, and thus considers the movement of the moving obstacle at the collision prediction point. Thus, it is possible to generate a moving route that can reach the target position in the shortest time. This makes it possible to shorten the time to reach the target position without being affected by the movement of the moving obstacle at the collision prediction point.

By setting the obstacle area in the three-dimensional space including the time axis, the obstacle area can be expressed by a mathematical formula, so that a conventional route planning method such as A * or RRT can be applied, and the calculation of the movement route becomes easy. .
By setting an obstacle area for a plurality of moving obstacles, it is possible to suppress the generation of a largely detoured moving route, so that it is possible to shorten the time to reach the target position.

(2nd Embodiment)
A second embodiment will be described with reference to FIGS. The second embodiment is characterized in that a traversable area is provided corresponding to the type of a moving obstacle.
As shown in FIG. 9, an obstacle identification unit 17 is added to the control unit 9. The obstacle specifying unit 17 can identify the type of the moving obstacle by capturing, for example, a person or a forklift that is a moving obstacle using a camera.

  In a factory, a place where a pedestrian passes or a place where a forklift passes is generally set in advance. Therefore, a traversable area corresponding to the type of the moving obstacle is set in advance, and when the type of the moving obstacle is detected by the obstacle identifying unit 17, the obstacle is set in the traversable area set according to the type. Set an area.

  Specifically, for example, in a place where a person is regulated to pass in a straight line, a rectangular parallelepiped traversable area is set in advance in a three-dimensional space as shown in FIG. If a person trying to pass through the passable area is detected, an obstacle area corresponding to the movement of the person is set in the passable area, and the obstacle area is avoided to reach the target position in the shortest time. To generate a moving route.

  According to such an embodiment, the traversable area is set in advance in accordance with the type of the moving obstacle, and the obstacle area is set in the traversable area, so that a shorter moving path is calculated. This makes it possible to shorten the time required to reach the target position.

(Third embodiment)
A third embodiment will be described with reference to FIG. The third embodiment is characterized in that a route is searched in consideration of the running performance of the AGC 1.

  The running performance of the AGC 1 is limited by the maximum speed, the maximum acceleration, the maximum angular speed, and the maximum angular acceleration. Therefore, based on at least one of the movement information of the maximum speed, the maximum acceleration, the maximum angular velocity, and the maximum angular acceleration, the route generation range (the shaded area in FIG. 11) that can be reached by the AGC 1 is calculated, and the area beyond that is calculated. Is restricted so that a route search is not performed.

As a specific example, in the case of the AGC 1 capable of omnidirectional movement using a mecanum wheel as in the present embodiment, for example, if the limit of the maximum speed is defined, the path generation range becomes a conical range as expressed by the following equation. Therefore, the route is searched within the range.

  According to such an embodiment, the route generation range is set in consideration of the traveling performance of the AGC 1, and the route search is performed within the range. Generation of a route can be suppressed, and a deviation between the calculated moving route and the actually moving route can be suppressed.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIG. The fourth embodiment is characterized in that an obstacle area corresponding to a moving obstacle that does not affect the movement of the AGC 1 is excluded from the calculation target.

As shown in FIG. 12, for the moving obstacles B and C that do not affect the movement of the AGC 1, that is, move in a direction different from the movement direction of the AGC 1, the obstacle area is excluded from the calculation.
Specifically, both the speed vector of the AGC 1 and the speed vector of the moving obstacle are multiplied by a positive number, and it is determined whether or not the speed vectors intersect, so that the moving obstacles A to C prevent the movement of the AGC 1 from moving. It is to determine whether or not, and a determination method other than this method may be used.

  According to such an embodiment, by calculating the route by excluding the obstacle region corresponding to the moving obstacle that is not involved in the movement of the AGC 1, the calculation time in the route planning can be shortened. It becomes short, and it becomes possible to start moving quickly.

(Other embodiments)
The setting of the target position may be set on a straight line parallel to the time axis at the target position, and when the target position is reached, the movement path may be generated so as to move on the straight line.
Alternatively, a three-dimensional grid map may be added to the three-dimensional space, a cubic grid overlapping the predicted area of the moving obstacle may be set as the obstacle area, and path planning may be performed.
As a part of the route planning, a method other than the method described above may be used.

  Although the present disclosure has been described in accordance with the embodiments, it is understood that the present disclosure is not limited to the embodiments and the structures. The present disclosure also encompasses various modifications and variations within an equivalent range. In addition, various combinations and forms, and other combinations and forms including only one element, more or less, are also included in the scope and spirit of the present disclosure.

  In the drawing, 1 is an AGC (autonomous moving body), 2 is a traveling unit, 3 is a control device (autonomous moving body control device), 8 is an obstacle detection unit, 13 is an obstacle state calculation unit, and 14 is an obstacle area calculation. , 15 is a route planning unit, 16 is a movement control unit, and 17 is an obstacle specifying unit.

Claims (7)

An obstacle detection unit (8) for detecting a moving obstacle located around the autonomous moving body (1);
An obstacle state calculation unit (13) that calculates movement information including a position and a time of the moving obstacle detected by the obstacle detection unit;
An obstacle area calculation unit (14) that calculates, as an obstacle area, a movement position of the moving obstacle at every predetermined time based on the movement information;
A route planning unit (15) configured to generate a travel route of the autonomous mobile using the obstacle area configured by the continuous predetermined time;
A movement control unit (16) that controls the movement of the autonomous moving body along the movement path;
Autonomous mobile control device equipped with   The autonomous mobile body control device according to claim 1, wherein the obstacle area is set as a three-dimensional space represented by a moving position of the autonomous mobile body in a two-dimensional space and an elapsed time. An obstacle identification unit (17) for identifying the type of the moving obstacle by the obstacle detection unit;
The route planning unit is set as a traversable area through which the moving obstacle passes, and the trajectory is set within the traversable area set according to the type of the moving obstacle identified by the obstacle identifying unit. The autonomous mobile body control device according to claim 1, wherein an obstacle area is set.   The route planning unit sets a route generation range of the autonomous mobile based on the movement information including any one or more of a maximum speed, a maximum acceleration, a maximum angular speed, and a maximum angular acceleration of the autonomous mobile. The autonomous mobile body control device according to any one of claims 1 to 3.   The route planning unit calculates the moving direction of the moving obstacle by the obstacle detecting unit, and does not calculate the obstacle region when the moving direction of the moving obstacle is not toward the moving route. The autonomous mobile control device according to any one of claims 1 to 4.   The autonomous mobile body control device according to any one of claims 1 to 5, wherein the route planning unit calculates each of the obstacle areas corresponding to two or more of the moving obstacles. An autonomous mobile body (1) including a traveling unit (2) and a control device (3),
The control device includes:
An obstacle detection unit (8) for detecting a moving obstacle located around the traveling unit;
An obstacle state calculation unit (13) that calculates movement information including a position and a time of the moving obstacle detected by the obstacle detection unit;
An obstacle area calculation unit (14) that calculates, as an obstacle area, a movement position of the moving obstacle at every predetermined time based on the movement information;
A route planning unit (15) configured to generate a travel route of the traveling unit using the obstacle region configured by the continuous predetermined time;
A movement control unit (16) that controls movement of the traveling unit along the movement path;
An autonomous mobile body configured to have:

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