Position estimating system and position estimating method for mobile robot

Abstract

To provide a position estimating system and a position estimating method for a mobile robot, which can prevent the mobile robot from losing track of its own position indoors in a building and can facilitate accurate and smooth movement of the mobile robot.SOLUTION: A position estimating system 1 is provided with a mobile robot 10 including an infrared emitting device 14 and a control device for controlling the movement, and a light receiving device 40 installed on the ceiling 8 of a building 3 or installed on a ceiling mounting portion attached to the ceiling 8. The control device estimates the position of the mobile robot 10 on the basis of position information based on information on the light emitted from the infrared emitting device 14 and received by the light receiving device 40.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a position estimation system and a position estimation method for a mobile robot.

Background Art

[0002] Conventionally, as a position estimation system for a mobile robot, there is one described in Patent Document 1. In this position estimation system, the mobile robot includes a lidar sensor and a storage unit. In this position estimation system, the position of the mobile robot is estimated by comparing the terrain information acquired by the mobile robot via the lidar sensor with the terrain information previously stored in the storage unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor of the present case has found the following new problems. Specifically, it has been found that in an indoor space, a mobile robot may lose its self-position and be unable to perform a task. In particular, in a space such as inside a large atrium of a building, where the ceiling is high, the indoor space is wide, and the space is surrounded by glass walls, waves (for example, lasers, light rays, etc.) emitted by sensors such as lidar sensors mounted on the mobile robot may pass through the side walls and not be easily reflected by the side walls, making it difficult for the mobile robot to acquire information on the reflected waves. It has been found that the case where the movement of the mobile robot is hindered becomes remarkable. Therefore, an object of the present disclosure is to provide a position estimation system and a position estimation method for a mobile robot that can suppress the loss of the self-position of the mobile robot in the indoor area of a building and make it easy for the mobile robot to move accurately and smoothly.

Means for Solving the Problems

[0005] To solve the above problems, a position estimation system for a mobile robot according to the present disclosure includes a mobile robot having one of a light emitting device and a light receiving device, and a control device for controlling movement, and the other of the light emitting device and the light receiving device installed on the ceiling of a building or installed on a ceiling mounting portion attached to the ceiling, and the control device estimates the position of the mobile robot based on position information based on information on light emitted from the light emitting device and received by the light receiving device.

[0006] The position information of the light emitting device or the light receiving device attached to the ceiling or the ceiling mounting portion is known in advance. Therefore, the information on the light emitted from the light emitting device and received by the light receiving device includes position information. According to the present disclosure, since the mobile robot acquires information on the light emitted from the light emitting device and received by the light receiving device, it can acquire information based on the known position information of the light emitting device or the light receiving device attached to the ceiling or the ceiling mounting portion. Therefore, by simply attaching the light emitting device or the light receiving device to the ceiling or the ceiling mounting portion located above the vicinity of the place where the mobile robot is likely to lose its own position, the mobile robot can be prevented from losing its own position, and the mobile robot can be easily moved accurately and smoothly.

[0007] Further, the light emitting device is mounted on the mobile robot, the light receiving device is installed on the ceiling or installed on a ceiling mounting portion attached to the ceiling, and a communication device that transmits position information based on information on light emitted from the light emitting device and received by the light receiving device to the mobile robot is provided, and the light emitting device may emit light in a substantially vertical direction.

[0008] According to this configuration, since the light emitting device emits light in a substantially vertical direction, it is easy to accurately estimate the light emission position, and thus the existence position of the mobile robot. The light may be any light, for example, visible light, ultraviolet light, or infrared light. However, when the light is infrared light, since the infrared light with excellent straightness is emitted in a substantially vertical direction, the infrared light emission position is more easily estimated accurately.

[0009] In addition, since the light-emitting device is configured to be mounted on the mobile robot, it is easy to reduce the number of light-emitting devices whose running costs and maintenance costs are likely to be higher than those of the light-receiving device, and it is easy to reduce the running costs and maintenance costs.

[0010] Further, the light-emitting device is mounted on the mobile robot, and the light-receiving device is installed on the ceiling or installed in a ceiling mounting portion attached to the ceiling. A communication device that transmits position information based on the information of the light emitted from the light-emitting device and received by the light-receiving device to the mobile robot is provided. The light-receiving device includes a plurality of light-receiving portions arranged at intervals. The position information may include the one or more pieces of information related to the light received by one or more of the plurality of light-receiving portions.

[0011] According to this configuration, the light-receiving device includes a plurality of light-receiving portions arranged at intervals, and the control device estimates the position of the mobile robot based on the one or more pieces of information related to the light received by one or more light-receiving portions. Depending on the specifications, in this configuration, when only one light-receiving portion receives light, the position of the mobile robot can be estimated to be near directly below the one light-receiving portion, and it is easy to accurately estimate the position of the mobile robot. Also, in this configuration, even when two or more light-receiving portions receive light, it is easy to accurately estimate the position of the mobile robot by analyzing the difference in the information of the light received by the two or more light-receiving portions.

[0012] Further, when N and M are natural numbers satisfying (N + M) ≥ 4, in a plan view when the plurality of light-receiving portions are viewed in the vertical direction from below, the plurality of light-receiving portions may include N × M array light-receiving portions arranged in a matrix with substantially the same pitch in N rows and M columns.

[0013] Regarding N×M array light-receiving units arranged in a matrix, in the above plan view, the row direction and the column direction are orthogonal. The pitch may be defined as the center-to-center distance in the plan view between the two light-receiving surfaces of two adjacent array light-receiving units in the row direction, and the pitch coincides with the center-to-center distance in the plan view between the two light-receiving surfaces of two adjacent array light-receiving units in the column direction. Also, the N×M array light-receiving units may be installed on a ceiling that spreads horizontally, or may be installed on a surface inclined with respect to the horizontal direction.

[0014] According to this configuration, since the N×M array light-receiving units are arranged on a checkerboard with the same pitch in the plan view, it is easy to accurately and easily analyze the differences in the information of the light received by three or more array light-receiving units, and it is easy to accurately estimate the position of the mobile robot.

[0015] Also, the position information may be information based on the intensity of the light received by two or more of the light-receiving units.

[0016] According to this configuration, since the information of the light received by two or more light-receiving units is the information of the intensity of the light, it is possible to accurately and easily analyze the differences in the information of the light received by two or more light-receiving units.

[0017] Also, the shortest distance from the side wall of the building in the other of the light-emitting device and the light-receiving device installed on the ceiling or installed on a ceiling mounting portion attached to the ceiling may be 2 m or more.

[0018] The inventor of the present case found in the test run of the mobile robot that the loss of the self-position of the mobile robot occurs significantly at the central part (a position farther from any side wall) in a space such as inside a large atrium of a building, where the ceiling is high, the indoor space is wide, and it is surrounded by glass walls.

[0019] According to this configuration, since the shortest distance from the side wall of the building in the other one of the light-emitting device and the light-receiving device installed on the ceiling or installed on the ceiling attachment part attached to the ceiling is 2 m or more, it is possible to effectively suppress the loss of the self-position of the mobile robot. Needless to say, the shortest distance from the side wall of the building in the other one of the light-emitting device and the light-receiving device installed on the ceiling or installed on the ceiling attachment part attached to the ceiling may be less than 2 m.

[0020] In addition, the method for estimating the position of the mobile robot according to the present disclosure includes a step of installing one of a light-emitting device and a light-receiving device on the mobile robot, a step of installing the other of the light-emitting device and the light-receiving device on the ceiling of the building or a ceiling attachment part attached to the ceiling, and a step of estimating the self-position of the mobile robot based on position information based on information on light emitted from the light-emitting device and received by the light-receiving device.

[0021] According to the present disclosure, since the mobile robot acquires information on light emitted from the light-emitting device and received by the light-receiving device, it is possible to acquire information based on the known position information of the light-emitting device or the light-receiving device attached to the ceiling or the ceiling attachment part. Therefore, by simply attaching the light-emitting device or the light-receiving device to the ceiling or the ceiling attachment part around a location where the mobile robot is likely to lose its self-position, it is possible to suppress the loss of the self-position of the mobile robot and make it easy for the mobile robot to move accurately and smoothly.

Effect of the Invention

[0022] According to the position estimation system and the position estimation method of the mobile robot according to the present disclosure, in the indoor area of the building, it is possible to suppress the loss of the self-position of the mobile robot and make it easy for the mobile robot to move accurately and smoothly.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0024] Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. In the following, when a plurality of embodiments, modification examples, etc. are included, it is initially assumed that new embodiments can be constructed by appropriately combining their characteristic parts. Also, in the following examples, the same components are denoted by the same reference numerals in the drawings, and redundant explanations are omitted. Further, the plurality of drawings include schematic diagrams, and the dimensional ratios of the vertical, horizontal, height, etc. of each member between different drawings do not necessarily match. Also, among the components described below, the components not described in the independent claims indicating the highest-level concept are arbitrary components and not essential components.

[0025] In the following description, each control device 20, 53 is preferably configured by a computer, for example, a microcomputer, and includes a control unit 21, 54 and a storage unit 22, 55. Each control unit 21, 54, that is, various processors includes, for example, a CPU (Central Processing Unit). Further, each storage unit 22, 55 is composed of a hard disk drive (HDD), a semiconductor memory, etc., and the semiconductor memory is composed of a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory). Each storage unit 22, 55 may be composed of only one storage medium or may be composed of a plurality of different storage mediums. The CPU reads and executes a program or the like stored in advance in the storage unit 22, 55. Further, the non-volatile memory stores in advance a control program, a predetermined threshold value, etc. Further, the volatile memory temporarily stores the read program and processing data.

[0026] In the following description, a case where the light-emitting device that emits light is an infrared-emitting device 14 that emits infrared rays is illustrated. However, the light-emitting device that emits light may emit any light other than infrared rays, for example, ultraviolet rays or visible light. When the light-emitting device emits ultraviolet rays or visible light, the ultraviolet rays or visible light may be laser light or may not be laser light. When the light-emitting device emits visible light, the light-receiving device may include an illuminometer.

[0027] FIG. 1 is a diagram for explaining the operation of the position estimation system 1 of the mobile robot 10 according to an embodiment of the present disclosure, and FIG. 2 is a block diagram showing the configuration of the position estimation system 1. The position estimation system (hereinafter, simply referred to as the position estimation system) 1 of the mobile robot 10 is installed in an indoor space, for example, in an indoor space such as a conference hall or an exhibition hall. When the position estimation system 1 is installed in a large indoor space whose side walls are covered with glass, the operational effects of the technology of the present disclosure can be significantly exhibited.

[0028] The mobile robot 10 is an autonomous mobile robot whose application (command operation) can be input manually or via wireless communication, or is stored (programmed) in advance. The mobile robot 10 is, for example, a mobile robot that performs delivery or food service in an indoor space, a cleaning robot that cleans the floor surface of an indoor space, a security robot that moves in an indoor space, a guiding robot that guides people to a destination in an indoor space, etc. Referring to FIG. 1, the mobile robot 10 accomplishes its purpose by automatically moving on the floor surface 4 of the facility in the indoor space 5.

[0029] As shown in FIG. 1, the position estimation system 1 includes a mobile robot 10 equipped with an infrared emission device 14 and a light receiving device 40 installed on the ceiling 8 of the building 3. The infrared emission device 14 is installed on the upper side of the mobile robot 10 and emits infrared rays R in the height direction of the mobile robot 10. The infrared rays R may be laser light or may not be laser light. In a state where the mobile robot 10 is placed on a horizontal plane, the height direction of the mobile robot 10 coincides with the vertical direction. The infrared emission device 14 is an example of a light emitting device.

[0030] The infrared emission device 14 includes a plurality of light receiving devices 50 attached to the ceiling 8 at intervals from each other. In this embodiment, all of the infrared emission devices 14 are directly attached to the ceiling 8. However, at least a part of the light receiving device may be installed in a ceiling mounting portion attached to the ceiling, or may be installed, for example, in a lighting device, an air conditioner, or an object attached to the ceiling.

[0031] As shown in FIG. 2, the mobile robot 10 includes a moving mechanism 11, a receiving unit 12, an operation unit 13, an infrared emission device 14, a position estimation sensor device 15, a horizontal reference device 16, a battery 17, and a control device 20. The control device 20 has a control unit 21 and a storage unit 22, and the control unit 21 includes a movement path specifying unit 21a, a movement control unit 21b, a position estimation unit 21c, a traveling obstacle determination unit 21d, and an infrared emission control unit 21e.

[0032] The moving mechanism 11 is composed of a known mechanism. For example, it is composed of a plurality of wheels, one or more motors for driving the wheels, and one or more motors for adjusting the moving direction of the wheels, etc. The mobile robot 10 performs the input or programmed movement by controlling the moving mechanism 11 based on the signal from the movement control unit 21b. For example, the rotation speed of the motor for driving the wheels and the phase of the motor for adjusting the moving direction of the wheels are controlled to perform the movement.

[0033] The receiving unit 12 receives the wireless signal transmitted from the light receiving device 40. The receiving unit 12 is composed of an interface for receiving data from the light receiving device 40 according to the wireless communication standard for performing wireless communication with the light receiving device 40. Examples of the wireless communication standard include Bluetooth (registered trademark), Wi-Fi (registered trademark), or Thread / ZigBee (registered trademark), etc. The receiving unit 12 may be able to receive a wireless signal including the usage (operation) information transmitted from an external remote control.

[0034] The operation unit 13 is provided for inputting the usage (operation) information. The operation unit 13 is composed of, for example, a touch panel in which a touch sensor and a display are integrated. Information related to operations and movements is input to the operation unit 13. The movement path specifying unit 21a specifies the movement path of the mobile robot 10 based on at least one of the usage (operation) information transmitted from an external remote control and the information input to the operation unit 13. When the mobile robot 10 moves based on the information of the wireless signal from an external remote control, the operation unit 13 may be omitted. The infrared emitting device 14 includes one or more infrared LEDs (Light Emitting Diodes) and a power supply device. The power supply device has a switching unit composed of a transistor or the like. The infrared emission control unit 21e controls the switching unit to selectively control the power supply to and power cut-off from the infrared LEDs. The light emitting surface of the infrared LEDs is directed upward in the height direction of the mobile robot 10.

[0035] Since it is a well-known configuration, it will not be described in detail, but the position estimation sensor device 15 has a plurality of sensors and acquires information that can estimate the position of the mobile robot 10. For example, the position estimation sensor device 15 has a millimeter-wave sensor (millimeter-wave radar), a lidar (Laser Imaging Detection and Ranging) sensor, an ultrasonic sensor, etc., senses distances from a plurality of walls and targets, wall shapes, etc., compares them with the map it has, and estimates its own position.

[0036] The millimeter-wave sensor irradiates millimeter waves (wavelengths of 1 to 10 millimeters in electromagnetic waves) and measures the distance to an obstacle and the direction of the obstacle from the time it takes for the millimeter waves to be reflected back from an object or the like. The lidar sensor measures scattered light with respect to the irradiation of pulsed laser light and detects the distance to an object at a long distance and the direction of the object. The ultrasonic sensor uses high-frequency ultrasonic waves to identify an object and is mainly used for detecting an object located at a short distance. The position estimation unit 21c recognizes the surrounding situation based on the information from those sensors and autonomously performs the input or programmed movement.

[0037] In addition to or instead of those sensors, the position estimation sensor device 15 may have a rotation speed detection sensor that detects the rotation speed (rotation speed of the wheels) of the wheels of the mobile robot 10 and a wheel direction detection sensor that detects the direction of the wheels. When the position estimation sensor device 15 is equipped with these sensors, based on the information on the position where the mobile robot 10 started moving, the continuous information on the rotation speed (speed) of the wheels from when the mobile robot 10 started moving until now, and the continuous information on the wheel direction, the position of the mobile robot 10 can be inductively estimated.

[0038] The horizontal level 16 is composed of a bubble tube level, a circular level, a laser level, etc., and detects the inclination angle of the plane orthogonal to the height direction of the mobile robot 10 with respect to the horizontal plane. Also, the battery 17 is composed of, for example, a primary battery or a secondary battery, and supplies power to each device. By using the horizontal level 16, the inclination angle of the infrared emission direction with respect to the vertical direction can be specified, so it becomes easier to accurately estimate the position of the mobile robot 10.

[0039] The light receiving device 40 includes a plurality of light receiving devices 50 arranged at intervals. Also, the light receiving device 50 includes a plurality of light receiving elements 51 arranged at intervals, a wireless transmission / reception unit 52 that constitutes a communication device, and a control device 53. The light receiving element 51 detects the intensity of infrared rays. FIG. 3 is a plan view when a plurality of light receiving elements 51 are viewed in the vertical direction from below in the vertical direction, and is a plan view for explaining the arrangement of a plurality of light receiving portions 57 in the plurality of light receiving elements 51.

[0040] As shown in FIG. 3, the plurality of light receiving portions 57 are arranged in a lattice (matrix) pattern on the ceiling 8. In this embodiment, the light receiving portions 57 of 3 rows and 3 columns are arranged on a chessboard with the same pitch in plan view. The nine light receiving portions 57 arranged in 3 rows and 3 columns constitute an array light receiving portion. The identification information and three-dimensional position information of each light receiving portion 57 are stored in advance in the storage portion 55 of the control device 53 in a state where they are associated with each other.

[0041] The light receiving element 51 outputs information regarding the intensity of the received infrared rays to the control device 53 in a state associated with the identification information. As a result, the control device 53 can recognize that infrared rays of a specific intensity have been detected at a specific three-dimensional position. The data generation unit 54a of the control unit 54 shown in FIG. 2 creates data to be transmitted to the mobile robot 10 based on the information from one or more light receiving elements 51 that have detected infrared rays among the nine light receiving elements 51 based on the information from the nine light receiving elements 51.

[0042] This data includes one or more pieces of information in which a three-dimensional position is associated with the intensity of infrared rays detected at that three-dimensional position. The wireless transceiver 52 is configured by an interface for transmitting data to the receiving unit 12 in a wireless communication standard for performing wireless communication with the receiving unit 12 of the mobile robot 10. The wireless transceiver 52 transmits the data generated by the data generation unit 54a to the receiving unit 12 of the mobile robot 10.

[0043] The position estimator 21c of the mobile robot 10 estimates its own position based on the information from the data generation unit 54a. Next, the principle of this position estimation will be briefly explained. In FIG. 3, an example of the intensity of infrared rays detected by nine light-receiving elements 51 is shown numerically. In this example, the light-receiving element 51a having the light-receiving part 57a detects infrared rays with an intensity of 85, the light-receiving element 51b having the light-receiving part 57b detects infrared rays with an intensity of 50, and the light-receiving element 51c having the light-receiving part 57c detects infrared rays with an intensity of 45.

[0044] The intensity of light is an index representing the brightness or energy of light, and the intensity of light is measured from several different viewpoints. As units of the intensity of light, for example, the following will be described. Photon Flux Density represents the number of photons per square meter per second. Photon Flux Density is generally expressed in the unit of μmol m -2 s -1 and is represented by such a unit. Irradiance is used when measuring the energy of light. The unit of irradiance is W m -2 and is as follows.

[0045] In FIG. 3, position C indicates the central position of the light beam of infrared rays that is emitted from the infrared ray emitting device 14 of the mobile robot 10 and reaches the ceiling 8. If position C is known, the position of the mobile robot 10 can be estimated. The positions of the respective parts of the light receiving device 50 are known, and the height of the light receiving device 50 from the floor surface 4 is approximately determined. Now, let this height be represented by h.

[0046] In three-dimensional coordinates, position C can be represented as (x, y, h) in three-dimensional coordinates. For example, The position of the mobile robot 10 can be represented as (x, y, 0), The position of the light receiving part 57a can be represented as (a1, b1, h), The position of the light receiving part 57b can be represented as (a2, b2, h), The position of the light receiving part 57c can be represented as (a3, b3, h). Also, the distance between the position C and the center position of each light receiving part 57a is (x - a1) 2 +(y - b1) 2 , (x - a2) 2 +(y - b2) 2 , (x - a3) 2 +(y - b3) 2 and so on.

[0047] Due to the characteristics of the infrared rays used, when the infrared rays are emitted in the height direction (coinciding with the substantially vertical direction), when the traveling distance of the light is h, the relationship between the distance from the center position (position C) of the infrared light beam in the plane orthogonal to the traveling direction of the infrared light and the light intensity is known. Therefore, the position estimation unit 21c can calculate x and y using the relationship between the distance from the position C and the light intensity, and estimate the position of the mobile robot 10.

[0048] In the technology of the present disclosure, a light source that emits light having a constant luminous intensity in all directions (emits uniform light in all directions) may be used. In this case, the light intensity is inversely proportional to the square of the distance. Therefore, when the distance between the mobile robot 10 and the light receiving part 57a is r1, the distance between the mobile robot 10 and the light receiving part 57b is r2, and the distance between the mobile robot 10 and the light receiving part 57c is r3, r1 2 ×85 = r2 2 ×50, r2 2 ×50 = r3 2 ×45, r1 2 = h 2 +(x - a1) 2 +(y - b1) 2 , r2 2 = h2 +(x - a2) 2 +(y - b2) 2 、 r3 2 =h 2 +(x - a3) 2 +(y - b3) 2 is established.

[0049] Therefore, since there are five unknowns, namely x, y, r1, r2, and r3, and there are also five mathematical expressions, the values of x and y can be obtained. The values of x and y change by changing the combination of the three light-receiving elements 51 that detect non-zero intensity. The values of x and y may be calculated by taking the average of the values calculated for all possible combinations of the three light-receiving elements 51.

[0050] The inventor of the present invention has found that in an indoor space, a mobile robot may lose its self-position and be unable to perform its tasks. In particular, in a space such as inside a large atrium of a building, where the ceiling is high, the indoor space is large, and it is surrounded by glass walls, waves emitted by sensors such as lidar sensors mounted on the mobile robot may not be reflected well by the side walls, for example, by passing through the side walls, making it difficult for the mobile robot to acquire information on the reflected waves, and the case where the movement of the mobile robot is hindered becomes prominent.

[0051] Furthermore, the inventor of the present invention has found that when the mobile robot 10 loses its self-position, it repeats small-scale movements within a local area for a long time and cannot get out of the local area for a long time, or repeats stopping and turning in a short time, etc., showing characteristic movements. In the present embodiment, in the indoor space where the position estimation system 1 is installed, the mobile robot 10 is test-driven many times in advance, and the operations when it loses its position, the normal operations in the area where the operation of losing its position occurs, and the data of the area where it loses its position are collected. The data of the plurality of characteristic operations, the data of the normal operations in the area where each characteristic operation occurs, and the data of the area where the position is lost are stored in advance in the storage unit 55 of the mobile robot 10.

[0052] The travel failure determination unit 21d determines whether the mobile robot 10 has encountered a travel failure based on data of a plurality of characteristic operations, data of normal operations in the region where each characteristic operation has occurred, and data of the region where the position has been lost. For example, the travel failure determination unit 21d may determine that the mobile robot 10 has encountered a travel failure when an operation including stop and turning is repeated alternately two or more times within a time of 10 seconds or less. Further, the travel failure determination unit 21d may determine that the mobile robot 10 has encountered a travel failure when the mobile robot stops three or more times in a state of facing different directions within a time of 10 seconds or less.

[0053] The light receiving device 50 is installed above the region where the mobile robot 10 is likely to encounter a travel failure. Data of the operation and the region where the position has been lost when it is determined that the mobile robot 10 has newly encountered a travel failure may be stored in the storage unit 55 afterwards, or the travel failure determination unit 21d may perform machine learning so that the determination of whether the mobile robot 10 has encountered a travel failure can be accurately performed as the travel distance of the mobile robot 10 increases.

[0054] Next, an example of the operation of the position estimation system 1 will be described. FIG. 4 is a flowchart for explaining an example of the operation procedure of the position estimation system 1. When the position estimation system 1 is constructed and the application (command operation) is input manually or by wireless communication, the control starts. In step S1, the input movement operation continues. Subsequently, in step S2, the travel failure determination unit 21d determines whether an obstacle has occurred in the movement of the mobile robot 10. If a negative determination is made in step S2, the process proceeds to step S3, and the movement path specifying unit 21a determines whether the input movement operation has been completed. If an affirmative determination is made in step S3, the control ends. If a negative determination is made in step S3, steps S1 and below are repeated.

[0055] On the one hand, when an affirmative determination is made in step S2, the process proceeds to step S4, where infrared rays are emitted in the height direction from the infrared emission device 14 of the mobile robot 10. Subsequently, in step S5, the light receiving device 40 receives the infrared rays. In step S6, the data generation unit 54a generates transmission data to the mobile robot 10, and the generated transmission data is transmitted to the receiving unit 12 of the mobile robot 10. As described above, the transmission data includes one or more pieces of information in which the three-dimensional position and the intensity of the infrared rays detected at that three-dimensional position are linked. In step S7, the position estimation unit 21c estimates the position of the mobile robot 10 based on the transmission data. By this estimation, the mobile robot 10 can recognize its own position, and then steps S1 and below are repeated.

[0056] As described above, the position estimation system 1 includes a mobile robot 10 having an infrared emission device (light emission device) 14 and a control device 20 that controls movement, and a light receiving device 40 installed on the ceiling 8 of the building 3 or installed on a ceiling mounting portion attached to the ceiling 8. Further, the control device 20 estimates the position of the mobile robot 10 based on the position information based on the information of the light emitted from the infrared emission device (light emission device) 14 and received by the light receiving device 40.

[0057] The position information of the infrared emission device 14 attached to the ceiling 8 or the ceiling mounting portion is known in advance. Therefore, the information of the light emitted from the infrared emission device 14 and received by the light receiving device 40 includes the position information. According to the present disclosure, since the mobile robot 10 acquires the information of the light emitted from the infrared emission device 14 and received by the light receiving device 40, it can acquire the information based on the known position information of the light receiving device 40. Therefore, by simply attaching the light receiving device 40 to the ceiling 8 or the ceiling mounting portion located above the vicinity of the location where the mobile robot 10 is likely to lose its own position, the mobile robot 10 can be prevented from losing its own position, and the mobile robot 10 can be moved accurately and smoothly.

[0058] Further, an infrared emission device 14 is mounted on the mobile robot 10, and a light receiving device 40 is installed on the ceiling 8 or installed in a ceiling mounting portion attached to the ceiling 8. A wireless transceiver (communication device) 52 that transmits position information based on the information of the light emitted from the infrared emission device 14 and received by the light receiving device 40 to the mobile robot 10 is provided. The infrared emission device 14 may emit infrared rays in the height direction of the mobile robot 10.

[0059] According to this configuration, since infrared rays with excellent straightness are emitted in a substantially vertical direction, it is easy to accurately estimate the emission position of the infrared rays and thus the existence position of the mobile robot 10. Further, since the infrared emission device 14 is mounted on the mobile robot 10, it is easy to reduce the number of infrared emission devices 14 whose running costs and maintenance costs are likely to be higher than those of the light receiving device 40, and it is easy to reduce the running costs and maintenance costs. Note that even when the light emitting device is not the infrared emission device 14 but emits light other than infrared rays (for example, ultraviolet rays or visible light), if the light is emitted in the height direction of the mobile robot 10 and emitted in a substantially vertical direction, it is easy to accurately estimate the existence position of the mobile robot 10.

[0060] Further, an infrared emission device 14 may be mounted on the mobile robot 10, and a light receiving device 40 may be installed on the ceiling 8 or installed in a ceiling mounting portion attached to the ceiling 8. A wireless transceiver 52 that transmits position information based on the information of the light emitted from the infrared emission device 14 and received by the light receiving device 40 to the mobile robot may be provided. The light receiving device 40 includes a plurality of light receiving portions 57 arranged at intervals, and the position information based on the information of the light emitted from the infrared emission device 14 and received by the light receiving device 40 may include the information related to the light received by one or more light receiving portions 57 included in the plurality of light receiving portions 57.

[0061] According to this configuration, the light receiving device 40 includes a plurality of light receiving units 57 arranged at intervals, and the control device 20 estimates the position of the mobile robot 10 based on the above-mentioned one or more pieces of information related to the light received by one or more light receiving units 57. Depending on the specifications, in this configuration, when only one light receiving unit 57 receives light, the position of the mobile robot 10 can be estimated to be near directly below the one light receiving unit 57, and it is easy to accurately estimate the position of the mobile robot 10. Further, in this configuration, even when two or more light receiving units 57 receive light, it is easy to accurately estimate the position of the mobile robot 10 by analyzing the difference in the information of the light received by the two or more light receiving units 57.

[0062] In the example shown in FIG. 3, the array light receiving units were arranged in 3 rows and 3 columns. However, when N and M are natural numbers satisfying (N + M) ≥ 4, in a plan view when looking at a plurality of light receiving units 57 in the vertical direction from below, the plurality of light receiving units 57 may include N × M array light receiving units arranged in a matrix with a substantially identical pitch and arranged in N rows and M columns.

[0063] Here, regarding the N × M array light receiving units arranged in a matrix, in the above-mentioned plan view, the row direction and the column direction are orthogonal. The pitch may be defined as the center-to-center distance in the above-mentioned plan view between the two light receiving surfaces of two adjacent array light receiving units in the row direction, and the pitch coincides with the center-to-center distance in the above-mentioned plan view between the two light receiving surfaces of two adjacent array light receiving units in the column direction. Further, the N × M array light receiving units may be installed on a ceiling extending in the horizontal direction, or may be installed on a surface inclined with respect to the horizontal direction.

[0064] According to this configuration, since the N × M array light receiving units are arranged on a checkerboard with the same pitch in a plan view, it is easy to accurately and easily analyze the difference in the information of the light received by three or more array light receiving units, and it is easy to accurately estimate the position of the mobile robot 10.

[0065] Further, the position information based on the information of the light emitted from the infrared emission device 14 and received by the light receiving device 40 may be information based on the intensity of the light received by two or more light receiving units 57.

[0066] According to this configuration, it is possible to accurately and easily analyze the difference in the information of the light received by two or more light receiving units. Note that the information of the light detected by the light receiving device may be wavelength information or the like of the light, and may not be the intensity information of the light.

[0067] In addition, the shortest distance from the side wall of the building 3 in the light receiving device 40 installed on the ceiling 8 or installed in the ceiling mounting portion attached to the ceiling 8 may be 2 m or more.

[0068] The inventor of the present invention has found through the running test of the mobile robot 10 that the loss of the self-position of the mobile robot 10 occurs significantly at the central part (a position farther from any side wall) in a space where the ceiling is high, the indoor space is wide, and the space is surrounded by glass walls, such as inside the large atrium of the building.

[0069] According to this configuration, since the shortest distance from the side wall of the building 3 in the light receiving device 40 installed on the ceiling 8 or installed in the ceiling mounting portion attached to the ceiling 8 is 2 m or more, it is possible to effectively suppress the loss of the self-position of the mobile robot 10. Needless to say, the shortest distance from the side wall of the building 3 in the light receiving device 40 installed on the ceiling 8 or installed in the ceiling mounting portion attached to the ceiling 8 may be less than 2 m.

[0070] In addition, the method for estimating the position of the mobile robot according to the present disclosure includes a step of installing an infrared emission device 14 on the mobile robot 10, a step of installing a light receiving device 40 on the ceiling 8 of the building 3 or in a ceiling mounting portion attached to the ceiling 8, and a step of estimating the self-position of the mobile robot 10 based on the position information based on the information of the light emitted from the infrared emission device 14 and received by the light receiving device 40.

[0071] According to the present disclosure, since the mobile robot 10 acquires information on the light emitted from the infrared emission device 14 and received by the light receiving device 40, it is possible to acquire information based on the known position information of the light receiving device 40 attached to the ceiling 8 or the ceiling attachment portion. Therefore, by simply attaching the light receiving device 40 to the ceiling 8 or the ceiling attachment portion around a location where the mobile robot 10 is likely to lose its self-position, the mobile robot 10 can be prevented from losing its self-position, and the mobile robot 10 can be moved accurately and smoothly.

[0072] The present disclosure is not limited to the above-described embodiments and their modifications, and various improvements and changes can be made within the scope of the matters described in the claims of the present application and their equivalent scope.

[0073] For example, the case where the mobile robot 10 is equipped with a light emitting device and the light receiving device 40 is fixed to the ceiling or the ceiling attachment portion has been described. However, the mobile robot may be equipped with a light receiving device, and the light emitting device may be fixed to the ceiling or the ceiling attachment portion.

[0074] Also, the case where the position of the mobile robot 10 is estimated by the mobile robot 10 has been described. However, the position of the mobile robot 10 may be estimated by the light receiving devices 40, 140, and the position estimation information of the mobile robot 10 may be wirelessly transmitted from the light receiving devices 40, 140 to the mobile robot 10.

[0075] Also, the case where all of the plurality of light receiving portions 57 are arranged on the grid of equal pitch in a plan view when viewed from the lower side in the vertical direction has been described. However, the light receiving device may have only one light receiving portion. Or, as shown in FIG. 5, the light receiving device 140 may include one or more light receiving devices 150, and the plurality of light receiving portions 151 included in the light receiving device 150 do not have to be arranged on the grid of equal pitch. Even in this case, in order to accurately and easily estimate the position of the mobile robot, when N and M are natural numbers satisfying (N + M) ≧ 4, in a plan view when the plurality of light receiving portions 151 are viewed in the vertical direction from the lower side, it is preferable that the plurality of light receiving portions 151 include N × M array light receiving portions arranged in a matrix of N rows and M columns with substantially the same pitch.

Description of Signs

[0076] 1 Position Estimation System, 3 Building, 4 Floor Surface, 5 Indoor Space, 8 Ceiling, 10 Mobile Robot, 11 Moving Mechanism, 12 Receiver, 13 Operation Unit, 14 Infrared Emission Device, 15 Position Estimation Sensor Device, 16 Horizontal Level, 17 Battery, 20, 53 Control Device, 21, 54 Control Unit, 21a Moving Route Specifying Unit, 21b Movement Control Unit, 21c Position Estimation Unit, 21d Traveling Obstacle Determination Unit, 21e Infrared Emission Control Unit, 22, 55 Memory Unit, 40, 140 Light Receiving Device, 50, 150 Light Receiving Equipment, 51 Light Receiving Element, 52 Wireless Transceiver, 54a Data Generation Unit, 57, 57a, 57b, 57c, 151 Light Receiving Unit.

Claims

1. A mobile robot having one of a light emitting device and a light receiving device, and a control device for controlling movement, and the other of the light emitting device and the light receiving device installed on the ceiling of a building or installed on a ceiling mounting portion attached to the ceiling, and a position estimation system for a mobile robot, wherein the control device estimates the position of the mobile robot based on position information based on information on light emitted from the light emitting device and received by the light receiving device.

2. The light emitting device is mounted on the mobile robot, and the light receiving device is installed on the ceiling or installed on a ceiling mounting portion attached to the ceiling, and includes a communication device that transmits position information based on information on light emitted from the light emitting device and received by the light receiving device to the mobile robot, The light emitting device emits light in the height direction of the mobile robot. The position estimation system for a mobile robot according to claim 1.

3. The light emitting device is mounted on the mobile robot, and the light receiving device is installed on the ceiling or installed on a ceiling mounting portion attached to the ceiling, and includes a communication device that transmits position information based on information on light emitted from the light emitting device and received by the light receiving device to the mobile robot, The light receiving device includes a plurality of light receiving portions arranged at intervals, The position information includes the information related to the light received by one or more of the light receiving portions included in the plurality of light receiving portions. The position estimation system for a mobile robot according to claim 1.

4. When N and M are natural numbers satisfying (N + M) ≧ 4, in a plan view when the plurality of light receiving portions are viewed in the vertical direction from below, the plurality of light receiving portions include N×M array light receiving portions arranged in a matrix in N rows and M columns with substantially the same pitch. The position estimation system for a mobile robot according to claim 3.

5. The position information is information based on the intensity of light received by two or more of the light receiving portions. The position estimation system for a mobile robot according to claim 3 or 4.

6. The shortest distance from the side wall of the building in the other of the light emitting device and the light receiving device installed on the ceiling or installed on a ceiling mounting portion attached to the ceiling is 2 m or more. The position estimation system for a mobile robot according to claim 1.

7. A step of installing one of a light emitting device and a light receiving device on a mobile robot, and installing the other of the light emitting device and the light receiving device on the ceiling of the building or a ceiling mounting portion attached to the ceiling; estimating the position of the mobile robot based on position information based on information on light emitted from the light emitting device and received by the light receiving device; A method for estimating the position of a mobile robot, comprising:

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