JP2005063184A - Self-propelled moving device and position correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-propelled moving device capable of surely arriving at a destination by correcting the position coordinate data of the self-propelled moving device. <P>SOLUTION: This self-propelled moving device has a drive part 112 so as to travel in a route in which a light emitting device for transmitting a unique identification code as optical signal is arranged. The device further comprises an arithmetic part 110 for calculating the measured position coordinate from the traveling distance and traveling direction obtained by measuring the operation of the drive part; a light receiving part 102 for converting the optical signal to an electric signal; a recognition part 104 for recognizing the identification code from the electric signal; a range finding part 106 for calculating distance data to the light emitting device based on the amplitude of the electric signal; a direction detection part 107 for calculating advancing direction data based on a plurality of distance data; and a correction part 108 for calculating an actual position coordinate based on the identification code, the distance data and the direction data, and correcting the measured position coordinate data according to the actual position coordinate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a self-propelled mobile device and a position correction method.

  Conventionally, in order for a self-propelled mobile device to reach its destination autonomously, a guide cable that emits electromagnetic waves and a guide tape that reflects light have been provided in the path. Self-propelled mobile devices have moved along these guide cables or guide tapes. However, laying a guide cable or a guide tape over the entire route in advance requires a lot of labor. In this case, in order to change the route, it is necessary to re-install a guide tape or the like.

  Conventionally, there is a method of measuring the current position of the self based on the amount of rotation of the gyro and the wheel of the self-propelled mobile device. According to this method, a guide cable and a guide tape are not necessary. However, there is a problem that an accurate current position cannot be measured due to wheel misalignment or gyro drift.

  In order to cope with this problem, the robot described in Patent Document 1 includes a light receiving unit including a plurality of light receiving elements arranged in the left-right direction of the robot, and a light transmitting unit that irradiates light to a position where the robot main body is guided. The movement direction of the robot body is calculated according to the light receiving state of the light receiving unit.

  The robot described in Patent Document 2 includes an infrared transmission / reception unit and a distance detection unit. The infrared transmission / reception means communicates with the position correction means fixedly arranged on the path using infrared rays, thereby correcting the position data of the robot to preset position data. The distance sensing means measures the separation distance data and thereby corrects the position error of the robot.

Further, in the robot described in Patent Document 3, the user has position signal generating means, and the robot receives direction signal from the position signal generating means and detects direction transmission means for detecting the transmission direction. I have.
JP 2002-215235 A No. 2821375 patent Japanese Utility Model Publication No. 4-40714

  The robot of Patent Document 1 needs to include a light emitting unit (light transmitting unit) in order to guide the robot. In addition, the robot requires a large number of light receiving elements in order to control the moving direction of the robot with high resolution. Further, since it is necessary to arrange a large number of light receiving elements on the left and right, this robot is not suitable for miniaturization.

  In the robot of Patent Document 2, the separation distance data measured by the distance sensing means does not necessarily indicate the distance between the position correction means that transmitted the unique code signal and the robot. For example, when a plurality of position correction means are arranged close to each other, it is unclear which distance correction data indicates the distance between the position correction means and the robot. Therefore, the robot may not be able to correct the position coordinate data accurately.

  In the robot of Patent Document 3, since the light emitting part of the position signal generating means is installed on the user's head, the height of the light emitting part and the light receiving part do not match depending on the height of the user's back. Therefore, when a light receiving element with low directivity of light receiving sensitivity is used, there arises a problem that the light receiving unit does not react. In order to avoid this problem, when a light receiving element with a wide directivity of light receiving sensitivity is used, the light receiving unit receives not only the direct light from the light emitting unit but also the light reflected by the surrounding environment. As a result, the robot cannot specify the position of the position signal generating means and cannot reach the position where the user exists.

  Accordingly, an object of the present invention is to provide a self-propelled mobile device that can correct the position coordinate data of the self-propelled mobile device and reliably reach the destination.

A self-propelled mobile device according to an embodiment according to the present invention is a self-propelled mobile device including a drive unit that can travel in a route where a light-emitting device that transmits a unique identification code as an optical signal is arranged. There,
A position coordinate calculation unit that calculates a position coordinate on measurement based on a travel distance and a travel direction obtained by measuring the operation of the drive unit, an optical signal transmitted from the light emitting device, and the optical signal A light receiving unit for converting the signal into a signal, a code recognition unit for recognizing the identification code from the electric signal from the light receiving unit, and between the light emitting device and the light receiving unit based on the amplitude of the electric signal from the light receiving unit A distance measuring unit that calculates distance data indicating a distance, a direction detection unit that calculates direction data indicating a traveling direction based on a plurality of the distance data, a position based on the identification code, the distance data, and the direction data A position coordinate correction unit that calculates coordinates and corrects the position coordinates on the measurement according to the position coordinates.

A position correction method according to an embodiment of the present invention includes a drive unit that can travel in a path in which a light emitting device that transmits a unique identification code as an optical signal is disposed, and receives an optical signal from the light emitting device. A position correction method for correcting the position of a self-propelled mobile device including a light receiving unit,
A step of calculating position coordinates in measurement based on a travel distance and a travel direction obtained by measuring the operation of the drive unit; and the light receiving unit receives an optical signal transmitted from the light emitting device, and the optical signal Converting the signal into an electric signal, recognizing the identification code from the electric signal, and calculating distance data indicating a distance between the light emitting device and the light receiving unit based on an amplitude of the electric signal. Calculating direction data indicating a traveling direction based on a plurality of the distance data; calculating position coordinates based on the identification code, the distance data, and the direction data; And a correction step for correcting the position coordinate data.

  The self-propelled mobile device according to the present invention corrects the position coordinate data of the self-propelled mobile device and can reliably reach the destination.

  Embodiments of the present invention will be described below with reference to the drawings. These embodiments do not limit the present invention.

  The self-propelled mobile device according to the embodiment of the present invention identifies the light-emitting device by an optical signal from the light-emitting device arranged in the path, and uses the optical signal to self-propelled movement with the light-emitting device. Detect the distance to the device. As a result, the self-propelled mobile device can correct the position coordinate data and reliably reach the destination.

(First embodiment)
FIG. 1 is a block diagram of a self-propelled robot 100 (hereinafter simply referred to as a robot 100) according to a first embodiment of the present invention. The robot 100 includes a light receiving unit 102, a code recognition unit 104, a distance measurement unit 106, a direction detection unit 107, a position correction unit 108, a position detection unit 110, a control unit 112, a drive unit 114, an encoder 116, a gyro 117, and a path generation unit. 118, a destination position input unit 120 and surrounding map information 122 are provided.

  The robot 100 includes, for example, two left and right wheels as the driving unit 114, and can move by the two wheels. The target position input unit 120 is a keyboard, a touch panel, or the like that can input coordinate data of a target position. The storage unit 122 stores map information in a region where the robot 100 can move and the position coordinates of the light emitting device 200. When the coordinate data of the target position is input to the target position input unit 120, the route generation unit 118 generates an appropriate route based on the map information in the storage unit 122. The appropriate route is, for example, a shortest route from the robot 100 to the target position or a route that the robot 100 can pass through. The control unit 112 controls the driving unit 114 in accordance with the route generated by the route generation unit 118 and moves the robot 100.

  The drive unit 114 is provided with an encoder 116 for each of the left and right wheels. The gyro 117 measures the angular velocity in the traveling direction of the robot 110. The encoder 116 and the gyro 117 measure the travel direction and travel distance of the robot 100, and the position detection unit 110 calculates the position coordinates of the robot 100 from these measurement results using an odometry calculation method. Hereinafter, the position coordinates of the robot 100 measured by the position detection unit 110 are referred to as “measurement position coordinates”. The position detection unit 110 periodically calculates the position coordinates on the measurement of the robot 100 and feeds back the position coordinates on the measurement to the control unit 112. The control unit 112 controls the drive unit 114 based on the measurement position coordinates obtained from the position detection unit 110.

  On the other hand, the light emitting device 200 is fixedly disposed at a target position of the robot 100. The light emitting device 200 stores an identification code. This identification code is used to distinguish the light emitting device 200 from other light emitting devices, or to distinguish the light emitting device 200 from ambient light. The light emitting device 200 converts the identification code into an optical signal and emits it.

  In the robot 100, the light receiving unit 102 receives an optical signal from the light emitting device 200, and converts the optical signal into an electrical signal corresponding thereto. The light receiving unit 102 is, for example, a photodiode. The code recognition unit 104 recognizes the identification code of the light emitting device 200 based on the electric signal from the light receiving unit 102. The distance measuring unit 106 calculates distance data indicating the distance between the light emitting device 200 and the robot 100 using the same electrical signal from the light receiving unit 102. Further, the direction detection unit 107 detects direction data indicating the traveling direction of the robot 100 with respect to the light emitting device 200 based on the plurality of distance data. That is, in this embodiment, the identification code, distance data, and direction data are derived from the same optical signal received by the light receiving unit 102.

  The position coordinates of the light emitting device 200 are stored in advance in the storage unit 122 in association with the identification code. Therefore, the position correction unit 108 can recognize the position coordinates of the light emitting device 200 having the identification code recognized by the code recognition unit 104. Based on the position coordinates of the light emitting device 200, the distance data between the light emitting device 200 and the robot 100, and the direction data indicating the actual traveling direction of the robot 100 with respect to the light emitting device 200, the position correction unit 108 determines the “actual position coordinates” of the robot 100. Can be calculated. This calculation method will be described later.

  The position correction unit 108 further corrects the measurement position coordinates of the robot 100 obtained from the position detection unit 110 to the actual position coordinates of the robot 100. The control unit 112 drives the drive unit 114 according to the corrected position coordinates. The position detection unit 110 starts calculating the position coordinates on the measurement of the robot 100 again from the corrected position coordinates.

  The code recognition unit 104, the distance measurement unit 106, and the position correction unit 108 may be configured by different processors. These may be constituted by one processor.

  By periodically correcting the measurement position coordinates of the robot 100 to the actual position coordinates, the robot 100 can reliably reach the target position. In addition, the light emitting device 200 is disposed in the vicinity of the target position, and the robot 100 moves based on the measurement position coordinates when positioned far from the target position, and transmits an optical signal only when positioned near the target position. It may be used to correct position coordinates on measurement.

  FIG. 2 is a block diagram illustrating a configuration of the light emitting device 200. The light emitting device 200 includes a storage unit 210 that stores an identification code, a modulation circuit 220 that modulates the identification code, and a light emitting element 230 that converts the identification code into an optical signal and emits it. The light emitting element 230 is, for example, an LED or a laser diode. Typically, it is an infrared light emitting LED. The identification code stored in the storage unit 210 is modulated by the modulation circuit 220 and then emitted from the light emitting element 230 as an optical signal. The modulation circuit 220 may be, for example, a circuit that modulates to a carrier frequency of 38 kHz that is generally used for the operation of AV equipment and air conditioners. When the light emitting element 230 has small directivity and the light receiving unit 102 cannot receive an optical signal even when the robot 100 is sufficiently close to the light emitting device 200, a plurality of light emitting elements 230 are arranged at equal angles in the radiation direction, or convex mirrors are arranged. Use to expand the emission angle.

  FIG. 3 is a block diagram illustrating a configuration of the light receiving unit 102 in the robot 100. The light receiving unit 102 includes a light receiving element 310, an amplifier 320, a BPF (Band Pass Filter) 330, a detector 340, an A / D (Analogue / Digital) converter 350, a waveform shaper 360, and a latch circuit 370.

  4A to 4E are timing charts showing the operation of the light receiving unit 102. FIG. With reference to these timing charts, the operation of the light receiving unit 102 shown in FIG. 3 will be described.

  The light receiving element 310 receives an optical signal and converts it into an electrical signal. FIG. 4A shows the waveform of the electrical signal at this time. Next, the amplifier 320 amplifies this electrical signal with a predetermined amplification factor, and uses the signal modulated by the carrier frequency by the BPF 330 to cut the noise component. FIG. 4B shows the waveform of the electrical signal after passing through the amplifier 320 and the BPF 330.

  Next, the electrical signal is transmitted to the A / D converter 350 and the waveform shaper 360 through the detector 340. The A / D converter 350 converts the electrical signal into a digital signal. On the other hand, the waveform shaper 360 shapes the waveform of the electrical signal shown in FIG. 4B so that the code recognition unit 104 can recognize the identification code, and converts it into a digital value shown in FIG. 4C. To do.

  Based on the digital value obtained from the waveform shaper 360, the latch circuit 370 is a voltage value (amplitude) converted into a digital signal by the A / D converter 350 when the digital value shown in FIG. Latch. FIG. 4D shows the timing at which the latch circuit 370 executes latching. An upward arrow shown in FIG. 4D indicates a time when the latch circuit 370 starts A / D conversion of the electrical signal. A downward arrow shown in FIG. 4D indicates the time when the latch circuit 370 executes latching to hold the converted voltage value.

  The voltage value of the electrical signal held by the latch circuit 370 is transmitted to the distance measuring unit 106. Since the voltage value of the electrical signal is proportional to the signal intensity of the optical signal received by the light receiving element 310, the distance measuring unit 106 can calculate the distance between the light emitting device 200 and the robot 100 based on the voltage value of the electrical signal. it can. Note that the light emission intensities of the plurality of light emitting elements 200 are known in advance. Preferably, the light emission intensities of the plurality of light emitting elements 200 are equal.

  On the other hand, the digital value obtained by shaping by the waveform shaper 360 is transmitted to the code recognition unit 104. The code recognition unit 104 converts this digital value into an identification code for identifying the light emitting device 200. FIG. 4E shows a digital value of the identification code. The digital value of the identification code is different from the digital value shown in FIG. 4C, and the digital value is determined according to the low level length of the electric signal.

  5 to 7 are diagrams illustrating how the robot 100 reaches the target position. With reference to these drawings, the operation in which the position correction unit 108 detects the actual position coordinates of the robot 100 will be described in detail. First, referring to FIG. 5, robot 100 travels according to measurement position coordinates until light emitting device 200 enters light receiving range A of light receiving unit 102. The robot 100 travels assuming that the target position is in the direction of the arrow.

Next, referring to FIG. 6, the light emitting device 200 enters the receiving range A, the code recognition unit 104 recognizes the identification code, the ranging unit 106 measures the distance data r _1. Further, when the robot 100 moves by the distance r ₃ , the code recognition unit 104 recognizes the identification code again, and the distance measurement unit 106 measures the distance data r ₂ . The position correction unit 108 confirms that the identification code in the distance data r ₁ is the same as the identification code in the distance data r ₂ . The direction detection unit 107 calculates the direction data θ ₂ from the following equations 1 and 2.
r ₁ sin (θ ₁ ) = r ₂ sin (θ ₂ ) (Formula 1)
r ₂ cos (θ ₁ ) −r ₃ = r ₂ cos (θ ₂ ) (Formula 2)

Further, the position correction unit 108 can calculate the actual position coordinates of the robot 100 based on the distance data r ₂ and the direction data θ ₂ , and make the measured position coordinates coincide with the actual position coordinates. To correct.

  Next, referring to FIG. 7, the robot 100 moves in the direction of the light emitting device 200. As described above, by periodically repeating the operations shown in FIGS. 5 to 7, the robot 100 can reliably reach the target position.

  FIG. 8 is a flowchart showing the operation of the robot 100. The operation shown in FIG. 8 is similar to the operation shown in FIG. 5 to FIG. 7, when the robot 100 moves based on the measurement position coordinates when located far from the target position and when located near the target position. Only the optical signal is used to move while correcting the position coordinates on the measurement. The light emitting device 200 is fixedly disposed at a target position.

  First, the coordinates of the target position are input to the target position input unit 120 (S10). The route generation unit 118 generates a route from the map information and the self position calculated from the position detection unit 110 to the target position (S20). The robot 100 moves according to the generated route (S30). At this time, the robot 100 moves while periodically calculating position coordinates on measurement.

  When the robot 100 moves to the vicinity of the target position and the light receiving unit 102 receives the optical signal from the light emitting device 200 (S40), the position correcting unit 108, as described with reference to FIGS. 100 actual position coordinates are measured (S50).

  The position correction unit 108 determines whether or not the measurement position coordinates are different from the actual position coordinates (S60). If the measured position coordinates are different from the actual position coordinates, the position correction unit 108 corrects the measured position coordinates to the actual position coordinates (S70). The route generation unit 118 newly generates a route based on the corrected position coordinates (S80). The control unit 112 drives the drive unit 114 along this path (S90).

  On the other hand, when the position coordinates on measurement are the same as the actual position coordinates, the position correction unit 108 does not correct the position coordinates on measurement. In this case, the robot 100 continues to move according to the route generated in step S20.

  If the light receiving unit 102 does not receive the optical signal from the light emitting device 200 in step S40, the process returns to step S30, and the robot 100 moves according to the measurement position coordinates until the light receiving unit 102 receives the optical signal. Continue.

  The position detection unit 110 determines whether the robot 100 has reached the target position (S100). If the robot 100 has not reached the target position, the process returns to step S30. When the robot 100 reaches the target position, a series of operations of the robot 100 ends. Note that the robot 100 may decelerate or stop when the distance between the target position and the robot 100 is equal to or less than a predetermined distance.

  In the present embodiment, both the identification code and the distance data are derived from the same optical signal received by the light receiving unit 102. Therefore, even when a plurality of light emitting devices 200 are arranged, it is easy to determine which light emitting device 200 the distance data indicates. Therefore, the position correction unit 108 can accurately correct the position coordinates on measurement, and the robot 100 can accurately reach the target position.

  In addition, this embodiment includes only one light receiving unit 102. Therefore, this embodiment is excellent in miniaturization and is low in cost.

(Second Embodiment)
FIG. 9 is a block diagram of a self-propelled robot 400 (hereinafter simply referred to as the robot 400) according to the second embodiment of the present invention. The robot 400 is different from the first embodiment in that it includes a plurality of light receiving units 102a and 102b. The distance between the light receiving portion 102a and the light receiving portion 102b is set in advance a predetermined distance (in this embodiment is r _3). In addition, the light receiving units 102a and 102b simultaneously receive the optical signals from the light emitting device 200. Thereby, the robot 400 can simultaneously acquire a plurality of distance data.

FIG. 10 is a diagram illustrating a positional relationship between the robot 400 and the light emitting device 200. FIG. 10 is similar to FIG. The robot 400 is moving assuming that the target position is in the direction of the arrow. When the light receiving units 102a and 102b receive the optical signal from the light emitting device 200, the code recognition unit 104 recognizes the identification code from the signals received by the light receiving units 102a and 102b. Distance measuring unit 106 calculates the distance data _{r 2} between the light emitting device 200 and the distance data _{r 1} and the light emitting device 200 between the light receiving portion 102a and the light receiving portion 102b.

The position correction unit 108 calculates the direction data θ ₁ and θ ₂ of the light emitting device 200 with respect to the robot 400 by substituting the distance data r ₁ , r _2, and r ₃ into Equations 1 and 2. Furthermore, the position correction unit 108 can calculate the actual position coordinates of the robot 400 based on the distance data r ₁ and r ₂ and the direction data θ ₁ and θ ₂ . The position correcting unit 108 corrects the actual position coordinates so that the measured position coordinates coincide with each other. Further, the robot 400 corrects the traveling direction so that the direction data θ ₁ and the direction data θ ₂ are substantially equal.

  The robot 400 moves in the direction of the light emitting device 200 in accordance with the corrected measurement position coordinates. The robot 400 can reliably reach the target position by repeating this correction operation periodically. The operation flow of the robot 400 is the same as the flow shown in FIG.

  In the first embodiment, one light receiving unit 102 receives a light signal a plurality of times while the robot 100 is moving, thereby acquiring a plurality of distance data. However, since the present embodiment includes a plurality of light receiving units 102a and 102b, a plurality of distance data can be acquired at a time when the light receiving units 102a and 102b simultaneously receive an optical signal. The actual position coordinates of the robot 400 can be obtained from the plurality of distance data. Therefore, in the present embodiment, the actual position coordinates of the robot 400 can be obtained even when the robot 400 is stopped. Furthermore, this embodiment has the same effect as the first embodiment.

  In the first and second embodiments, the light emitting device 200 is arranged at the target position. However, the robot 100 or 400 can also be applied when the target position and the position of the light emitting device 200 do not match. Hereinafter, such a case will be described as a modification.

(Modification of the first embodiment)
FIG. 11 is a diagram illustrating a modification of the first embodiment. In this modification, the light emitting device 200 is disposed at the corner of the obstacle, and the target position and the position of the light emitting device 200 do not match. While the robot 100 moves on the route indicated by the broken line, the distance measuring unit 106 measures the distance data r ₁ and r ₂ . As in the first embodiment, the direction data θ ₁ and θ ₂ are calculated from the distance data r ₁ , r _2, and r ₃ , and the actual position coordinates of the robot 100 are detected. The position correction unit 108 corrects the measured position coordinates to the actual position coordinates. Furthermore, it is possible on the basis of the direction data theta _2, to correct the movement direction of the robot 100.

  This modification has the same effect as the first embodiment. Furthermore, the robot 100 can reliably reach the target position even when the target position and the position of the light emitting device 200 do not match.

(Modification of the second embodiment)
FIG. 12 is a diagram illustrating a modification of the second embodiment. Also in this modified example, the light emitting device 200 is disposed at the corner of the obstacle, and the target position and the position of the light emitting device 200 do not match. The robot 400 moves to the target position along a route indicated by a broken line. The distance measuring unit 106 measures the distance data r ₁ and r _{2 based} on the optical signals received by the light receiving units 102a and 102b. Similar to the second embodiment, the direction data θ ₁ and θ ₂ are calculated from the distance data r ₁ , r _2, and r ₃ , and the actual position coordinates of the robot 400 are detected. The position correction unit 108 corrects the measurement position coordinates to the actual position coordinates. Furthermore, it is possible on the basis of the direction data theta _2, to correct the movement direction of the robot 400.

  This modification has the same effect as the second embodiment. Furthermore, the robot 400 can reliably reach the target position even when the target position does not match the position of the light emitting device 200.

1 is a block diagram of a robot 100 according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a configuration of a light emitting device 200. FIG. 3 is a block diagram showing a configuration of a light receiving unit 102 in the robot 100. 6 is a timing chart showing the operation of the light receiving unit. The figure which shows a mode that the robot 100 arrives at the target position. The figure which shows a mode that the robot 100 arrives at the target position. The figure which shows a mode that the robot 100 arrives at the target position. FIG. 6 is a flowchart showing the operation of the robot 100. The block diagram of the robot 400 according to 2nd Embodiment which concerns on this invention. The figure which shows the positional relationship of the robot 400 and the light-emitting device 200. FIG. The figure which shows the modification of 1st Embodiment. The figure which shows the modification of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Robot 102 Light receiving part 104 Code recognition part 106 Distance measurement part 107 Direction detection part 108 Position correction part 110 Position detection part 112 Control part 114 Drive part 116 Encoder 117 Gyro 118 Path | route generation part 120 Target position input part 122 Peripheral map information 210 Memory | storage Part 220 modulation circuit 230 light emitting element 310 light receiving element 320 amplifier 330 BPF
340 Detector 350 A / D converter 360 Waveform shaper 370 Latch circuit

Claims (5)

In a self-propelled mobile device having a drive unit that can travel in a route where a light emitting device that transmits a unique identification code as an optical signal is arranged,
A position coordinate calculation unit that calculates a position coordinate on measurement based on a travel distance and a travel direction obtained by measuring the operation of the drive unit;
A light receiving unit that receives an optical signal transmitted from the light emitting device and converts the optical signal into an electrical signal;
A code recognition unit for recognizing the identification code from an electric signal from the light receiving unit;
A distance measuring unit that calculates distance data indicating a distance between the light emitting device and the light receiving unit based on an amplitude of an electrical signal from the light receiving unit;
A direction detection unit that calculates direction data indicating a traveling direction based on a plurality of the distance data;
A self-propelled moving apparatus comprising: a position coordinate correction unit that calculates position coordinates based on the identification code, the distance data, and the direction data, and corrects the position coordinates on the measurement according to the position coordinates. The light emitting device transmits an optical signal including a unique identification code, modulated at a specific frequency,
A filter that passes a specific frequency component of the electrical signal from the light receiving unit;
A waveform shaper that shapes the electrical signal that has passed through the filter;
A latch circuit that holds the amplitude of the electrical signal that has passed through the filter when the electrical signal shaped by the waveform shaper is at a high level;
The code recognition unit is connected to the waveform shaper, recognizes the identification code from the electric signal waveform-shaped by the waveform shaper,
The self-propelled mobile device according to claim 1, wherein the distance measuring unit is connected to the latch circuit and calculates the distance data based on an amplitude of the electric signal held by the latch circuit.   The direction detection unit has a first position when the identification code when present at the first position is the same as the identification code when present at a second position different from the first position. Calculating the direction data based on the distance data when present at the second position, the distance data when present at the second position, and the distance between the first position and the second position. The self-propelled mobile device according to claim 1, wherein A plurality of the light receiving parts are provided apart from each other,
The code recognition unit recognizes the identification code based on the electrical signal from each of the light receiving units,
The distance measuring unit is based on the amplitude of the electric signal from the first light receiving unit when the identification codes from the first light receiving unit and the second light receiving unit are the same among the plurality of light receiving units. First distance data between the light emitting device and the first light receiving unit is calculated, and the light emitting device and the second light receiving unit are calculated based on the amplitude of the electric signal from the second light receiving unit. Calculating the second distance data between
The direction detection unit calculates the direction data based on the first distance data, the second distance data, and a distance between the first light receiving unit and the second light receiving unit. The self-propelled mobile device according to claim 1, wherein the mobile device is a mobile device. Position of a self-propelled mobile device including a drive unit that can travel in a route where a light emitting device that transmits a unique identification code as an optical signal is disposed, and a light receiving unit that receives an optical signal from the light emitting device A position correction method for correcting
Calculating the position coordinates on measurement by the travel distance and travel direction obtained by measuring the operation of the drive unit;
The light receiving unit receives an optical signal transmitted from the light emitting device, and converts the optical signal into an electrical signal;
Recognizing the identification code from the electrical signal;
Calculating distance data indicating a distance between the light emitting device and the light receiving unit based on an amplitude of the electrical signal;
Calculating direction data indicating a traveling direction based on a plurality of the distance data;
A position correcting method comprising: calculating a position coordinate based on the identification code, the distance data, and the direction data, and correcting the position coordinate data on the measurement according to the position coordinate.

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