JP7121489B2 - moving body - Google Patents

Description

The present invention relates to a moving body that measures distances to surrounding objects using a distance measuring sensor.

2. Description of the Related Art Among conventional moving bodies, one having a distance measuring sensor is known. By using the result of distance measurement by the distance measuring sensor, for example, self-position identification and positioning to a target position can be performed (see Patent Document 1, for example).

JP 2010-160671 A

However, as described in Patent Document 1 above, there is a problem that the accuracy of the position (position estimation result) obtained by self-localization is not so high. For example, a position obtained by self-localization may have an error on the order of tens of centimeters. In addition, when positioning to a target position as described in Patent Document 1, it is necessary to measure the distance used for the positioning in advance by actually arranging the moving body at the target position. , there was also a problem that the load for that is large.

The present invention has been made to solve the above problems, and it is possible to obtain information used for movement control with higher accuracy than self-localization, and the information used for positioning is It is an object of the present invention to provide a moving body that does not need to be measured in advance.

In order to achieve the above object, a mobile object according to the present invention is an autonomously moving mobile object comprising a moving mechanism for moving the mobile object and a range sensor for measuring distances to surrounding objects in a plurality of directions. , a wall detection unit that detects surrounding walls by a time-independent method using the measurement result of the range sensor, and a movement control unit that controls the movement mechanism using the detection result of the wall by the wall detection unit. ,
Such a configuration detects the surrounding walls in a time-independent manner, thus enabling detection of walls with higher accuracy and in a shorter time than time-dependent self-localization. Then, using the detection result of the wall, it becomes possible to detect, for example, a slip of the moving body or a deviation from the path of the moving body. Further, for example, the information used for positioning can be positioned using wall detection results without measuring in advance.

Further, in the moving body according to the present invention, the wall detection section may detect the wall by Hough transform from the measurement result.
Such an arrangement allows surrounding walls to be detected with greater accuracy than time-dependent self-localization.

Further, in the moving body according to the present invention, the wall detection section may detect the wall by the least squares method from the measurement result.
Such an arrangement allows surrounding walls to be detected in a shorter time than time-dependent self-localization.

Further, in the moving body according to the present invention, the movement control section may acquire the deviation of the moving body using the detection result of the wall by the wall detection section, and use the deviation to control the movement mechanism.
With such a configuration, for example, when slippage of the moving body is detected, the moving body is controlled to stop, and when deviation from the moving body's path is detected, the moving body is moved along the route. You will be able to control it to return to

Further, in the moving body according to the present invention, the movement control section may control the movement mechanism so as to eliminate the deviation.
With such a configuration, by using the detection result of the wall, it becomes possible to control the moving body to return to its original path. This allows for more precise movement.

In addition, the moving body according to the present invention further includes a current position acquisition unit that acquires the current position of the moving body by time-dependent self-localization using the measurement result of the ranging sensor. The movement mechanism may be controlled using the current position acquired by the acquisition unit.
With such a configuration, the current position acquired by the current position acquiring unit is used to grasp the global position and movement control is performed, and the detection result of the wall is used to detect local displacement. movement can be controlled by

According to the moving object of the present invention, it is possible to detect walls with higher accuracy than time-dependent self-positioning and in a short time. control can be realized.

1 is a block diagram showing the configuration of a moving object according to an embodiment of the present invention; FIG. 4 is a flow chart showing the operation of a moving object according to the same embodiment; FIG. 4 is a diagram for explaining detection of a wall in the same embodiment; FIG. 4 is a diagram for explaining detection of a wall in the same embodiment; FIG. 4 is a diagram for explaining wall detection using Hough transform in the same embodiment; A diagram showing an example of temporal change of the distance to the wall in the same embodiment. A diagram showing an example of time change of the angle with respect to the wall in the same embodiment. A diagram showing an example of temporal change of the distance to the wall in the same embodiment. A diagram showing an example of time change of the angle with respect to the wall in the same embodiment.

Hereinafter, a moving body according to the present invention will be described using embodiments. In the following embodiments, constituent elements and steps with the same reference numerals are the same or correspond to each other, and repetitive description may be omitted. The moving body according to the present embodiment detects surrounding walls using the distance measurement result of the distance measurement sensor, and performs movement control using the detection result.

FIG. 1 is a block diagram showing the configuration of a moving body 1 according to this embodiment. A moving body 1 according to the present embodiment moves autonomously, and includes a moving mechanism 11, a distance measuring sensor 12, a wall detecting section 13, a map storing section 14, a current position acquiring section 15, a moving and a control unit 16 . It should be noted that the autonomous movement of the mobile body 1 may mean that the mobile body 1 moves to the destination based on its own judgment, instead of moving according to an operation instruction received from a user or the like. The destination may, for example, be manually determined or automatically determined. Also, the movement to the destination may or may not, for example, be along a movement route. Further, moving to the destination by one's own judgment may be, for example, moving to the destination by the moving body 1 judging the traveling direction, movement, stop, or the like. Alternatively, for example, the moving body 1 may move so as not to collide with an obstacle. The mobile body 1 may be, for example, a trolley or a moving robot. The robot may be, for example, an entertainment robot, a surveillance robot, a transport robot, a cleaning robot, or a robot that shoots moving images or still images. , or other robots.

The moving mechanism 11 moves the moving body 1 . For example, the moving mechanism 11 may or may not be capable of moving the moving body 1 in all directions. Being able to move in all directions means being able to move in any direction. The moving mechanism 11 may have, for example, a running portion (eg, wheels) and a driving means (eg, a motor, an engine, etc.) that drives the running portion. In addition, when the moving mechanism 11 can move the moving body 1 in all directions, the traveling part may be an omnidirectional moving wheel (for example, an omni wheel, a mecanum wheel, etc.). For a mobile object that has omnidirectional wheels and is capable of moving in all directions, see Japanese Patent Application Laid-Open No. 2017-128187, for example. Since a known mechanism can be used as the moving mechanism 11, detailed description thereof will be omitted.

The ranging sensor 12 measures distances to surrounding objects in multiple directions. The distance sensor 12 may be, for example, a laser sensor, an ultrasonic sensor, a distance sensor using microwaves, a distance sensor using stereo images captured by a stereo camera, or the like. The laser sensor may be a laser range sensor (laser range scanner). Note that these distance measuring sensors are already known, and description thereof will be omitted. In this embodiment, the case where the distance measuring sensor 12 is a laser range sensor will be mainly described. Also, the moving body 1 may have one laser range sensor, or may have two or more laser range sensors. In the latter case, all directions may be covered by two or more laser range sensors. Further, when the distance measuring sensor 12 is an ultrasonic sensor, a distance sensor using microwaves, or the like, the distance in a plurality of directions may be measured by rotating the distance measuring direction of the distance measuring sensor 12. A plurality of distance measuring sensors 12 arranged in each direction may be used to measure distances in a plurality of directions. The distance measuring sensor 12 may measure distances in a predetermined range of directions, or may measure distances in all directions. For example, the distance measuring sensor 12 may measure distances in multiple directions only in front of the mobile object 1 . Further, for example, the distance measuring sensor 12 may measure distances in a plurality of directions at predetermined angular intervals around the entire circumference (360 degrees). The angular intervals may be constant, such as 1-degree intervals, 2-degree intervals, 5-degree intervals, and the like. The information obtained from the ranging sensor 12 may be, for example, the distances to surrounding objects for each of a plurality of azimuth angles with respect to a certain orientation of the moving body 1 . By using the distance, it becomes possible to know what kind of objects exist around the moving body 1 in the local coordinate system of the moving body 1 .

FIG. 3 is a diagram for explaining the measurement of the distance to the wall W1 by the distance measuring sensor 12, and is a diagram of the moving body 1 viewed from above. As shown in FIG. 3, the angles and distances to a plurality of measurement points P are measured by emitting laser beams in various directions from the ranging sensor 12 of the moving body 1 moving in the direction of the thick arrow. can be measured. Note that FIG. 3 shows a situation in which the laser is emitted only in the direction of the wall W1, but the laser is normally emitted in other directions as well. Then, by using the measurement result regarding the measurement point P, each measurement point in the local coordinate system of the moving body 1 shown in FIG. The coordinate values of P can be obtained. Acquisition of coordinate values for each measurement point P may be performed by the distance measurement sensor 12 or may be performed by another component. In the present embodiment, a case where the distance measuring sensor 12 also acquires coordinate values in the local coordinate system of the moving body 1 for each measurement point will be mainly described.

The wall detection unit 13 uses the measurement results from the distance measurement sensor 12 to detect surrounding walls in a time-independent manner. The wall is usually a partition of a room or a wall of a passage, but the side of a large piece of equipment may be detected as a wall. Detecting the position of the wall by a time-independent method means detecting the current position of the wall without using past information. Note that the time-dependent method includes, for example, Monte Carlo position estimation, which will be described later. Detecting a wall may mean detecting the position of the wall in the local coordinate system of the moving body 1, or detecting the distance from the moving body 1 to the wall, or detecting the distance between the moving body 1 and the wall. It may be to detect the angle with. Detecting the position of the wall may be specifying an equation that indicates the position of the wall in the local coordinate system. If the wall is represented by a straight line in the two-dimensional coordinate system, the position of the wall in the local coordinate system of the moving body 1 can be detected by detecting the distance and angle from the moving body 1 to the wall. Detecting the distance and angle from the moving body 1 to the wall can be considered to be the same as detecting the position of the wall in the local coordinate system. It is preferable that the wall detection unit 13 detects a wall while the moving body 1 is moving. This is because the accuracy of the current position obtained by the time-dependent self-localization decreases during movement, whereas the detection accuracy of the wall detected by the wall detection unit 13 does not decrease. When the moving body 1 is stationary, the current position can be obtained with high accuracy even by time-dependent self-localization. The wall detection unit 13 may repeatedly detect the wall. For example, the wall detection unit 13 may detect walls at predetermined time intervals. The wall detection method by the wall detection unit 13 may be any method that does not depend on time. A method of detecting walls using the least squares method will be described. To simplify the explanation, it is assumed that the wall is flat. That is, the case where the wall is indicated by a straight line in the two-dimensional plane coordinate system will be described.

(1) Method of Detecting Walls Using Hough Transform In this method, the wall detection unit 13 detects walls by the Hough transform from the measurement results of the distance measuring sensor 12 . The Hough transform is a technique used to detect straight lines and curves. FIG. 5 is a diagram for explaining the Hough transform. Referring to FIG. 5, a straight line L1 passing through a certain point A (x1, y1) can be expressed as follows.
r=x1·cos θ+y1·sin θ

Here, r is the length of the normal line drawn from the origin to the straight line L1 in the local coordinate system (xy coordinate system), and θ is the angle of the normal line (angle with the x-axis). Note that, for example, r may be a real number, and θ may be a real number ranging from 0 to π. The above equation corresponds to one sinusoidal curve on the r, θ plane. Therefore, it is possible to specify sinusoidal curves on the r and θ planes according to coordinate values (x1, y1), (x2, y2), (x3, y3), . . . can. As shown in FIGS. 3 and 4, since the measurement points P are on a straight line, a plurality of sinusoidal curves corresponding to the plurality of measurement points P intersect at one point, and the intersection is ( A straight line passing through the measurement point P is indicated by r1, θ1). That is, in the xy local coordinate system of FIG. 4, a straight line passing through the measurement point P is obtained as in the following equation. Specifying this equation will find the position of the wall in the local coordinate system.
r1=x·cos θ1+y·sin θ1

On the other hand, since measurement errors actually exist, a plurality of sinusoidal curves corresponding to a plurality of measurement points P intersect at two or more points, and the intersections (r1, θ1), (r2, θ2) , (r3, .theta.3), and so on are obtained. Each straight line corresponding to each intersection will indicate the position of multiple walls, but they originally indicate the position of a single wall. Therefore, for example, among the plurality of intersection points, the intersection point that has the largest number of curves passing through that intersection point may be specified as the intersection point corresponding to the straight line corresponding to the position of the wall. Then, the straight line corresponding to the specified intersection point may be used as the straight line indicating the position of the wall. Further, among the plurality of intersections, the representative values of r and θ are specified for the intersections through which the curve exceeding the threshold passes, and the straight line corresponding to the representative values r and θ is used as the straight line indicating the position of the wall. good too. The representative value may be, for example, an average value, an intermediate value, or the like. Note that r indicates the distance to the wall, and θ indicates the angle of the wall. Therefore, obtaining r and θ corresponding to the specified intersection point may be detecting the wall. In this embodiment, such a case will be mainly described.

(2) Method of Detecting Walls Using Least Squares Method In this method, the wall detection unit 13 detects walls by the least squares method from the measurement results of the distance measuring sensor 12 . For example, as shown in FIG. 4, it is possible to acquire coordinate values in the local coordinate system for a plurality of measurement points P corresponding to wall W1. Therefore, the wall detection unit 13 may identify a straight line in the local coordinate system corresponding to the wall W1 by using each coordinate value and using the method of least squares. In this case, if the measurement points used in the least-squares method include measurement points other than the wall position, the detection accuracy of the wall position will be reduced accordingly. Therefore, the wall detection unit 13 may detect the wall using the least-squares method, for example, using measurement points that are certain to be the position of the wall. Whether or not the position of the wall is certain may be determined using, for example, the current position or a map, which will be described later. That is, a measurement point that can be determined to be a wall on the map even considering the error of the current position may be used to detect this wall. It should be noted that the method of using a plurality of coordinate values to identify a straight line most suitable for those coordinate values by the method of least squares is already known, and detailed description thereof will be omitted.

As described above, when walls are detected using the Hough transform or the least-squares method, walls can be detected with higher accuracy than time-dependent self-localization. Walls can be detected in less time than identification. Therefore, by using the wall detection result, finer movement control can be realized than by using the current position obtained by time-dependent self-localization. For example, by using wall detection results, it becomes possible to detect slips that were difficult to detect with time-dependent self-localization, and to perform positioning to a target position with higher accuracy. .

In the above description, the case where the wall is a plane, that is, the case where a wall indicated by a straight line on a two-dimensional plane is detected has been described, but this need not be the case. If the shape of the wall is a curve whose shape is known in advance (for example, an arc, a sine curve, an elliptical curve, etc.), such a curved wall may be detected. Since it is already known that curves can also be handled in the Hough transform and the least squares method, the description of detection of walls of curves is omitted.
Also, time-independent wall detection may be performed by methods other than the Hough transform and the least squares method.

The map storage unit 14 stores a map regarding the moving environment of the mobile body 1 . The map may indicate, for example, the positions of obstacles in the moving environment of the mobile object 1, that is, the positions of objects such as walls and equipment whose distance is to be measured by the distance measuring sensor 12. . Also, the map may be, for example, a map used for self-localization, or may be another map. In this embodiment, a case where the map is used for self-localization will be mainly described. Since the map used for self-localization is already known, its detailed description is omitted. The process by which the map is stored in the map storage unit 14 does not matter. For example, a map may be stored in the map storage section 14 via a recording medium, or a map transmitted via a communication line or the like may be stored in the map storage section 14 . The storage in the map storage unit 14 may be temporary storage in RAM or the like, or may be long-term storage. The map storage unit 14 can be realized by a predetermined recording medium (for example, semiconductor memory, magnetic disk, optical disk, etc.).

The current position acquisition unit 15 acquires the current position of the mobile object 1 . Acquisition of the current position may be performed, for example, using wireless communication, may be performed using the measurement result of the distance to surrounding objects, or may be performed by capturing an image of the surroundings. , may be done using other means by which the current position can be obtained. Known methods for acquiring the current position using wireless communication include, for example, a method using a GPS (Global Positioning System), a method using an indoor GPS, and a method using a nearby wireless base station. Further, for example, as a method of acquiring the current position by using the measurement result of the distance to the surrounding object or taking an image of the surrounding, for example, SLAM (Simultaneous Localization and Mapping) is known. Any method may be used. As the measurement result of the distance to the surrounding object, for example, the measurement result of the distance measuring sensor 12 may be used. In addition, when a pre-created map (for example, a map having measurement results of distances to surrounding objects, a map having a photographed image, etc.) is stored, the current position acquisition unit 15 uses the map to obtain the surrounding The current position may be obtained by identifying the position corresponding to the distance measurement to the object, or the current position may be obtained by capturing an image of the surroundings and using a map to identify the position corresponding to the captured result. You can get the position. At that time, the current position acquisition unit 15 may use the map stored in the map storage unit 14 . Also, the current position acquisition unit 15 may acquire the current position using, for example, an autonomous navigation system. Also, the current position acquisition unit 15 preferably acquires the current position including the orientation (direction) of the moving body 1 . The direction may be indicated, for example, by an azimuth angle measured clockwise, with north being 0 degrees, or by other directional information. The orientation may be obtained by an electronic compass or a geomagnetic sensor. In the present embodiment, a case will be mainly described in which the current position acquisition unit 15 acquires the current position by time-dependent self-localization using the measurement result of the distance measuring sensor 12 . It is also assumed that the map stored in the map storage unit 14 is used in the self-location identification. It should be noted that time-dependent self-localization may be performed, for example, by Monte Carlo localization. In Monte Carlo position estimation, for example, the current position is obtained as follows. First, the model position is estimated using the past position of the moving body 1 and the command speed, and a plurality of current position candidates are specified based on the model position. Then, with respect to the plurality of specified current position candidates, estimated observation positions of objects around the moving body 1 are calculated using a map. After that, the actual observed position by the distance measuring sensor 12 is compared with the estimated observed position, and the estimated observed position closest to the actual observed position is acquired as the final observed position, that is, the current position. Note that time-dependent self-localization methods such as Monte Carlo localization are already known, and detailed description thereof will be omitted.

The movement control unit 16 controls movement of the moving body 1 by controlling the movement mechanism 11 . The control of the movement may be control of the direction of movement of the mobile body 1, start/stop of movement, and the like. The movement control section 16 may control the movement mechanism 11 using the current position acquired by the current position acquisition section 15 . Further, for example, when a route is set, the movement control unit 16 may control the movement mechanism 11 so that the moving body 1 moves along the movement route. More specifically, the movement control unit 16 may control the movement mechanism 11 so that the current position acquired by the current position acquisition unit 15 is along the movement route. Further, the movement control unit 16 may control movement using a map. In that case, the movement control unit 16 may use a map stored in the map storage unit 14, for example.

Further, the movement control unit 16 controls the movement mechanism 11 using the detection result of the wall by the wall detection unit 13 . It should be noted that, as described above, using the detection result of the wall can realize finer movement control than using the current position. For example, the movement control unit 16 may acquire the displacement of the moving body 1 using the detection result of the wall by the wall detection unit 13 and control the movement mechanism 11 using the displacement. Acquisition of the deviation may be performed, for example, by acquiring the difference between the detected distance and angle with the wall and the reference value corresponding to them, and the change (deviation) in the distance and angle per unit time This may be done by obtaining The reference value may be, for example, a value calculated using a route, a map, or the like, or may be a distance or angle to a wall detected in the past (for example, just before). For example, as described above, when the distance r from the moving body 1 to the wall and the angle θ of the wall with respect to the moving body 1 are detected, the movement control unit 16 sequentially, You may remember. The results are, for example, shown in FIGS. 6A and 6B. FIG. 6A is a diagram showing temporal changes in the detected distance r to the wall, and FIG. 6B is a diagram showing temporal changes in the detected wall angle θ. As shown in FIG. 3, when the moving body 1 is moving along the wall W1, that is, when the moving body 1 is moving parallel to the wall W1, at time t in FIGS. 6A and 6B, As indicated by the small range, the distance r to the wall and the angle θ of the wall are substantially constant. On the other hand, as shown in FIGS. 6A and 6B, the distance r and the angle .theta. to the wall may change due to unevenness or inclination of the running surface, or due to wheel slip during movement. When at least one of the detected deviation of the distance r to the wall and the deviation of the angle θ to the wall is greater than or equal to a predetermined threshold value, the movement control unit 16 may stop the moving body 1, or may control the moving mechanism 11 so as to eliminate the deviation. In addition, in FIGS. 6A and 6B, a value detected in the past (a value within a small range of time t) may be used as a reference value for obtaining the deviation.

Note that, for example, the movement control unit 16 may stop the moving body 1 when the obtained displacement of the wall changes significantly in a short period of time. Specifically, the movement control unit 16 stops the moving body 1 when the deviation (change) per first unit time of at least one of the distance and the angle of the wall exceeds a predetermined threshold value. You may let This is because, in such a case, there is a high possibility that the moving body 1 is slipping or the like. The first time unit is predetermined, and may be, for example, the adjacent time interval between wall detection times. After stopping, the movement control unit 16 causes the wall detection unit 13 to detect the wall, the current position acquisition unit 15 to acquire the current position, and the like again to acquire the current position more accurately. , the movement control for returning to the route may be restarted, or the occurrence of an abnormality may be notified to a person in charge of maintenance or the like by a predetermined method. For example, as shown in FIGS. 6A and 6B, when the deviation (change) of the distance or angle per first unit time (here, it is assumed to be the time interval related to wall detection) becomes large. Alternatively, the movement control unit 16 may control the movement mechanism 11 so that the moving body 1 stops when this is detected.

Further, for example, if the above deviation does not occur for a short period of time, but the deviation regarding the wall increases over a long period of time, the movement control unit 16 may be configured to eliminate the deviation. You may control the moving mechanism 11 to. Specifically, the deviation per unit time of at least one of the distance and the angle of the wall is less than a predetermined threshold value, but the deviation per unit time of the second unit time is equal to or greater than the predetermined threshold value. In this case, the movement control unit 16 may perform control so as to eliminate the deviation. In that case, it is highly possible that the distance to the wall and the angle to the wall are gradually changing due to the unbalanced load and the condition of the running surface. The second unit time is a period longer than the first unit time. The second unit time may be, for example, twice or three times the first unit time, or longer. The predetermined threshold may be the same as the threshold used when performing stop control according to slip or the like. If there is a deviation in the distance between the walls, the movement control unit 16 may change the moving direction of the moving body 1 so as to reduce the deviation in the movement control for eliminating the deviation. good. Further, when the angle of the wall deviates, the movement control unit 16 rotates the moving body 1 so that the angle corresponding to the deviation becomes smaller in the movement control for eliminating the deviation. may be controlled. For example, as shown in FIGS. 6C and 6D, the difference in the distance and angle per the first unit time is small, but the difference in the second unit time (here, three times the first unit time, that is, the wall It is three times the time interval for detection.) If the deviation of the distance or angle becomes large, when the movement control unit 16 detects this, the movement control unit 16 moves so as to eliminate the deviation. Mechanism 11 may be controlled. It should be noted that the control for eliminating this deviation is based on the premise that the distance and angle to the wall do not change in the original movement, that is, in the movement in the absence of disturbances such as unbalanced loads. Therefore, when such a premise is satisfied, the movement control unit 16 may perform control to eliminate the deviation.

As described above, the movement control unit 16 performs control to stop the moving body 1 when, for example, the deviation per unit time of the detected wall exceeds the threshold value, and Although the deviation per unit time is not equal to or greater than the threshold, control may be performed to eliminate the deviation when the deviation per unit time is greater than or equal to the threshold.

Also, in the above description, the distance to the wall and the angle to the wall are essentially constant, and the movement control is performed using the change in deviation from the reference value, which is a constant value. It doesn't have to be. For example, when the moving body 1 moves diagonally with respect to the wall, the distance to the wall gradually increases. In such a case, the movement control unit 16 may acquire the displacement of the wall on the basis of the distance that gradually increases with movement. Even in such a case, if the angle with the wall is constant, the movement control unit 16 may perform movement control using the deviation regarding the angle with the wall.

Next, the operation of the moving body 1 will be explained using the flowchart of FIG.
(Step S101) The distance measurement sensor 12 measures the distance of surrounding objects and acquires the measurement result. The measurement results may be converted into coordinate values in the local coordinate system of the moving body 1 for each measurement point, as described above.

(Step S<b>102 ) The wall detection unit 13 detects surrounding walls using the measurement results from the distance measurement sensor 12 . For example, the wall detection unit 13 may or may not perform processing related to wall detection in all directions of the moving object 1 . When walls are detected in all directions, there is a possibility that even straight lines that are not original walls will be detected as walls. Therefore, for example, when a wall is detected by the Hough transform, the wall detection unit 13 may detect, as a wall, a straight line or the like corresponding to a number of intersections equal to or greater than a predetermined threshold. Further, the wall detection unit 13 identifies the position on the map corresponding to the current position by using the current position acquired by the current position acquisition unit 15 and the map stored in the map storage unit 14, for example. , specify the wall around the position on the map, and detect the wall only in the direction in which the wall exists or only in the direction in which the moving body 1 is moving at a constant distance or angle with respect to the wall. may be performed. A path may also be used, for example, for determining whether it is moving at a constant distance or angle with respect to a wall. Further, information about the detected wall, such as the distance to the wall and the angle of the wall, may be stored in a recording medium (not shown) in association with the time at that time.

(Step S103) The movement control unit 16 uses the detected wall information to determine whether the moving body 1 has shifted. For example, if the distance to the wall or the angle to the wall changes by a threshold value or more, it may be determined that the moving body 1 has deviated. If the moving body 1 is not displaced, the process proceeds to step S104, and if the moving body 1 is displaced, the process proceeds to step S105.

(Step S104) The movement control unit 16 performs normal movement control, that is, movement control when the moving body 1 is not displaced. This control of movement may be, for example, control of movement toward a destination. By repeating the movement control in step S104, the moving body 1 may reach the destination from the departure point.

(Step S105) The movement control unit 16 performs movement control when deviation occurs. For example, the movement control unit 16 may stop the moving body 1 when a large deviation occurs in a short period of time. Then, the movement control unit 16 may restart the movement after obtaining the current position or the like with high accuracy, or may contact the person in charge of maintenance or the like. Further, if a large deviation does not occur in a short period of time, but the deviation increases over time, the movement control unit 16 may control the movement mechanism 11 so as to eliminate the deviation. good.

(Step S106) The movement control unit 16 determines whether or not the destination has been reached. Then, if the destination is reached, the series of movement processing ends, and if not, the process returns to step S101. Note that the movement control unit 16 may determine whether or not the moving body 1 has reached the destination using the current position, or may determine using the wall detection result. In the former case, the movement control unit 16 determines that the mobile body 1 has reached the current position when the current position obtained by the current position obtaining unit 15 becomes a position corresponding to the destination. good too. In the latter case, for example, the target is a point where the distance to the front wall is D1 and the distance to the side (either right or left) wall is D2. The movement control unit 16 obtains the distances to the front and side walls obtained by the wall detection unit 13, and determines that the destination has been reached when the distances are D1 and D2. You can judge. By performing positioning using the wall detection result in this way, it is possible to achieve positioning with higher accuracy than positioning using the current position obtained by time-dependent self-localization. Also, in this case, in positioning using the distance to the wall, there is no need to measure information used for positioning in advance.

The order of processing in FIG. 2 is an example, and the order of each step may be changed as long as the same result can be obtained. Also, although not included in the flowchart of FIG. 2, it is assumed that acquisition of the current position by the current position acquisition unit 15 is repeatedly performed.

As described above, according to the moving object 1 according to the present embodiment, since the surrounding wall is detected by a time-independent method, the wall can be detected with higher accuracy and in a short time than the time-dependent self-localization. be detectable. Therefore, by using the wall detection result, the moving body 1 can realize highly accurate and real-time movement control. For example, using the wall detection result, it is possible to acquire the displacement of the moving body 1 with respect to the wall. It becomes possible to control the movement of the body 1. In this way, safer movement of the mobile body 1 can be realized, and more accurate movement of the mobile body 1 can be realized. On the other hand, time-dependent self-localization is less accurate and less real-time than wall detection according to the present embodiment. Therefore, for example, it is difficult to detect slippage using time-dependent self-localization results.

Note that the wall detected by the wall detection unit 13 can also be used to position the moving body 1 . For example, when an obstacle detection unit (not shown) detects another moving object moving toward the moving object 1 from the front, the movement control unit 16 detects the wall detected by the wall detection unit 13. By using it, the self-moving body 1 can be controlled to retreat near the wall. When the current position obtained by time-dependent self-localization is used, it is difficult to approach the wall due to the large error. This is because there is a danger of colliding with the wall if the robot is closer to the wall than the distance corresponding to the error. On the other hand, since the error in the detection result by the wall detection unit 13 is smaller than the error in the self-localization, it becomes possible to move to a position closer to the wall. In this way, it becomes possible to perform movement control so as to retreat at a position closer to the wall until another moving body passes by. Further, the detection result by the wall detection unit 13 can be used to perform positioning in a place surrounded by walls, such as in an elevator.

Further, in the present embodiment, when the current position is not used for movement control, the mobile body 1 does not have to include the current position acquisition unit 15 .

Further, in the above embodiments, each process or function may be implemented by centralized processing by a single device or single system, or may be implemented by distributed processing by multiple devices or multiple systems. It may be realized by

Further, in the above-described embodiment, when the information is passed between the components, for example, when the two components that exchange the information are physically different, one of the components output of information and reception of information by the other component, or one component if the two components that pass the information are physically the same from the phase of processing corresponding to the other component to the phase of processing corresponding to the other component.

In the above embodiments, information related to processing executed by each component, for example, information received, acquired, selected, generated, transmitted, or received by each component Also, information such as thresholds, formulas, addresses, etc. used by each component in processing may be stored temporarily or for a long period of time in a recording medium (not shown), even if not specified in the above description. Further, each component or an accumulation section (not shown) may accumulate information in the recording medium (not shown). Further, each component or a reading unit (not shown) may read information from the recording medium (not shown).

Further, in the above embodiment, if the information used in each component etc., for example, information such as thresholds, addresses and various set values used in processing by each component may be changed by the user, the above The user may or may not be able to change such information as appropriate, even if not explicitly stated in the description. If the information can be changed by the user, the change is realized by, for example, a reception unit (not shown) that receives a change instruction from the user and a change unit (not shown) that changes the information according to the change instruction. may The reception of the change instruction by the reception unit (not shown) may be, for example, reception from an input device, reception of information transmitted via a communication line, or reception of information read from a predetermined recording medium. .

Further, in the above embodiment, when two or more components included in the mobile object 1 have communication devices, input devices, etc., the two or more components may physically have a single device. , or may have separate devices.

Further, in the above embodiments, each component may be configured by dedicated hardware, or components that can be realized by software may be realized by executing a program. For example, each component can be realized by reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory by a program execution unit such as a CPU. During the execution, the program execution unit may execute the program while accessing the storage unit or recording medium. In addition, the program may be executed by being downloaded from a server or the like, or may be executed by reading a program recorded on a predetermined recording medium (for example, an optical disk, a magnetic disk, a semiconductor memory, etc.). good. Also, this program may be used as a program constituting a program product. Also, the number of computers that execute the program may be singular or plural. That is, centralized processing may be performed, or distributed processing may be performed.

Moreover, it goes without saying that the present invention is not limited to the above-described embodiments, and that various modifications are possible and are also included within the scope of the present invention.

As described above, according to the mobile object of the present invention, by using the detection result of the wall, it is possible to achieve highly accurate and real-time movement control, and it is useful as a mobile object that moves autonomously. .

1 Mobile 11 Moving Mechanism 12 Ranging Sensor 13 Wall Detecting Part 14 Map Storage Part 15 Current Position Acquisition Part 16 Movement Control Part

Claims (4)

A mobile body that moves autonomously,
a moving mechanism for moving the moving body;
a ranging sensor that measures distances to surrounding objects in multiple directions;
a wall detection unit that detects surrounding walls in a time-independent manner using the measurement results of the ranging sensor;
a current position acquisition unit that acquires the global current position of the moving object by time-dependent self-localization using the measurement result of the ranging sensor;
Using the detection result of the wall by the wall detection unit, the local displacement of the moving object is obtained, the displacement is used to control the moving mechanism, and the current position obtained by the current position obtaining unit is obtained. and a movement control unit that controls the movement mechanism using the moving body. 2. The moving body according to claim 1, wherein said wall detection unit detects a wall from said measurement result by Hough transform. 2. The moving body according to claim 1, wherein said wall detection unit detects a wall from said measurement result by a least-squares method. 4. The moving body according to any one of claims 1 to 3, wherein said movement control section controls said movement mechanism so as to eliminate said deviation.

Images