Map generation method, map generation device, and surface inspection device

Abstract

This map generation method, which is for generating a two-dimensional map of the movement path of a carriage 10 that moves on a surface of a cylindrical or columnar three-dimensional object 50, includes: an acquisition step for acquiring measurement results of the acceleration and angular velocity of the carriage 10 and a measurement result of the moving distance of the carriage 10; a circumferential angle calculation step for calculating the circumferential angle of the carriage 10 by applying the acceleration measurement result to a first map conversion formula; an axial coordinate calculation step for calculating the axial coordinate of the carriage 10 by applying the angular velocity measurement result and the moving distance measurement result to a second map conversion formula; and a map generation step for generating a two-dimensional map in which a position specified by the circumferential angle and the axial direction coordinate is recorded.

Description

[Technical Field]

[0001] The present disclosure relates to a map generation method and map generation device that generates a two-dimensional map of the surface of a three-dimensional object using a cart that moves on the surface of the three-dimensional object, and a surface inspection device that inspects the surface of a three-dimensional object. [Background technology]

[0002] As disclosed in Patent Document 1, a method for mapping the position and movement path of a cart traveling on the surface of a three-dimensional object is known, for example, of measuring the XY coordinates of the cart using an X-direction accelerometer, a Y-direction accelerometer, and an encoder attached to the cart. Also, as disclosed in Patent Document 2, a method is known in which the amount of movement of the cart is measured using a rotary encoder attached to the cart, and the position and movement path of the cart are mapped one-dimensionally. Furthermore, as disclosed in Patent Document 3, a method is known in which the three-dimensional coordinates of the cart are measured using multiple wire encoders attached to the cart. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-49730 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-50736 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-170766 Summary of the Invention [Problem to be solved by the invention]

[0004] In the method described in Patent Document 1, although it is possible to calculate the circumferential angle on the surface of a cylindrical object from the calculated XY coordinates of the cart, it is not possible to calculate the longitudinal movement distance. Note that information on the diameter of the cylindrical object is required to calculate the circumferential angle on the surface of the cylindrical object from the XY coordinates. In the method described in Patent Document 1, the position and movement path of the cart can only be mapped in the circumferential direction of the cylindrical object. Therefore, when inspecting a cylindrical object using a cart, it is necessary to limit the movement path of the cart to the circumferential direction or to limit the cart to straight travel without turning. In other words, when performing an inspection using the method described in Patent Document 1, the movement of the cart is significantly restricted, which limits the inspection content.

[0005] The method described in Patent Document 2 is capable of measuring the travel distance of a carriage on a cylindrical object and generating a one-dimensional flaw detection map during inspection of the cylindrical object. However, the circumferential angle of the carriage on the surface of the cylindrical object is unknown. Therefore, in order to inspect the entire surface of the cylindrical object, it is necessary to measure the circumferential angle of the carriage using a different method.

[0006] In the method described in Patent Document 3, by obtaining the three-dimensional coordinates of the carriage, it is possible to calculate the circumferential angle of the carriage relative to the surface of the cylindrical object and the longitudinal movement distance. However, in order to convert to the coordinate system of the cylindrical object, the diameter of the cylindrical object and a complex map calculation formula are required. In particular, the diameter of the cylindrical object is often unknown during inspection. When the diameter of the cylindrical object is unknown, there is a large error when converting from the three-dimensional coordinates of the carriage to the coordinate system of the cylindrical object.

[0007] In order to solve the above-mentioned problems, the present disclosure aims to provide a map generation method and map generation device that can easily and accurately generate a two-dimensional map of the position and movement path of a cart on the surface of a three-dimensional object, as well as a surface inspection device that can inspect the surface of a three-dimensional object. [Means for solving the problem]

[0008] A map generation method according to an embodiment of the present disclosure is a method for generating a two-dimensional map of a movement path of a carriage moving along the surface of a cylindrical or columnar three-dimensional object. The map generation method includes: an acquisition step of acquiring measurement results of an acceleration and an angular velocity of the carriage and a measurement result of a movement distance of the carriage along the surface of the three-dimensional object while the carriage moves along the surface of the three-dimensional object; a circumferential angle calculation step of calculating a circumferential angle of the carriage on the surface of the three-dimensional object by applying the measurement results of the acceleration acquired in the acquisition step to a first map conversion formula; an axial coordinate calculation step of calculating an axial coordinate of the carriage on the surface of the three-dimensional object by applying the measurement results of the angular velocity and the measurement results of the movement distance acquired in the acquisition step to a second map conversion formula; and a map generation step of generating a two-dimensional map recording positions identified by the circumferential angle calculated in the circumferential angle calculation step and the axial coordinate calculated in the axial coordinate calculation step.

[0009] A map generating device according to an embodiment of the present disclosure includes a generating unit that generates a two-dimensional map of a movement path of a bogie moving on a surface of a cylindrical or columnar three-dimensional object, and an acquiring unit that acquires measurement results of the acceleration and angular velocity of the bogie and measurement results of the movement distance of the bogie along the surface of the three-dimensional object. The generating unit applies the measurement results of the acceleration of the bogie to a first map conversion formula to calculate a circumferential angle of the bogie on the surface of the three-dimensional object, applies the measurement results of the angular velocity of the bogie and the measurement results of the movement distance of the bogie to a second map conversion formula to calculate an axial coordinate of the bogie on the surface of the three-dimensional object, and generates a two-dimensional map that records positions identified by the circumferential angle of the bogie and the axial coordinate of the bogie.

[0010] A surface inspection apparatus according to an embodiment of the present disclosure includes the map generation device described above and an inspection device that inspects the surface at a predetermined position when the carriage moves to the predetermined position, wherein a generation unit of the map generation device reflects the inspection result of the surface at the predetermined position in a point corresponding to the predetermined position in a two-dimensional map. [Effects of the Invention]

[0011] According to the present disclosure, there are provided a map generation method and map generation device that can easily and accurately generate a two-dimensional map of the position and movement path of a cart on the surface of a three-dimensional object, and a surface inspection device that can inspect the surface of a three-dimensional object. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a block diagram illustrating an example configuration of a map generation system according to the present disclosure. [Figure 2] FIG. 1 is a plan view illustrating an example of the configuration of a carriage according to the present disclosure. [Figure 3A] FIG. 2 is a schematic diagram showing an example of a cylindrical three-dimensional object for which a two-dimensional map is to be generated. [Figure 3B] This is a two-dimensional map in which the surface of the cylindrical three-dimensional object in FIG. 3A is developed and the position can be identified by the axial coordinate and circumferential angle of the cylinder. [Figure 4A] FIG. 10 is a diagram showing an example of a path along which a carriage moves on the surface of a cylindrical three-dimensional object along its axial direction. [Figure 4B] FIG. 4B is a two-dimensional map of the route in FIG. 4A. [Figure 5A] FIG. 10 is a diagram showing an example of a path along which a carriage moves in the circumferential direction on the surface of a cylindrical three-dimensional object. [Figure 5B] FIG. 5B is a two-dimensional map of the route in FIG. 5A. [Figure 6A] FIG. 10 is a cross-sectional view of a cylindrical three-dimensional object viewed in the positive axial direction, showing the axis of acceleration when the reference direction at the initial position of the carriage is clockwise in the circumferential direction. [Figure 6B] FIG. 10 is a cross-sectional view of a cylindrical three-dimensional object viewed in the positive axial direction, showing the axis of acceleration when the reference direction at the initial position of the carriage is counterclockwise in the circumferential direction. [Figure 6C] FIG. 10 is a cross-sectional view of a cylindrical three-dimensional object viewed in the positive axial direction, showing the axis of acceleration when the reference direction at the initial position of the carriage is the positive axial direction. [Figure 6D]FIG. 10 is a cross-sectional view of a cylindrical three-dimensional object viewed in the positive axial direction, showing the axis of acceleration when the reference direction at the initial position of the carriage is the negative axial direction. [Figure 7A] FIG. 10 is a diagram showing the angle of the reference direction of the carriage when the reference direction at the initial position of the carriage is clockwise in the circumferential direction in a plan view of the surface of a cylindrical three-dimensional object. [Figure 7B] FIG. 10 is a diagram showing the angle of the reference direction of the carriage when the reference direction at the initial position of the carriage is counterclockwise in the circumferential direction in a plan view of the surface of a cylindrical three-dimensional object. [Figure 7C] FIG. 10 is a diagram showing the angle of the reference direction of the carriage when the reference direction at the carriage's initial position is the positive axial direction in a plan view of the surface of a cylindrical three-dimensional object. [Figure 7D] FIG. 10 is a diagram showing the angle of the reference direction of the carriage when the reference direction at the initial position of the carriage is the negative axial direction in a plan view of the surface of a cylindrical three-dimensional object. [Figure 8] 10 is an example of a two-dimensional map in which the measurement results of the carriage movement path measured by executing the map generation method according to the present disclosure and the true position of the carriage are recorded on a two-dimensional plane. [Figure 9] 1 is a flowchart illustrating an example of a procedure for a map generation method and a surface inspection method according to the present disclosure. [Figure 10A] 10A and 10B are schematic diagrams showing modified examples of a cylindrical three-dimensional object for which a two-dimensional map is to be generated. [Figure 10B] 10B is a two-dimensional map in which the surface of the cylindrical three-dimensional object in FIG. 10A is developed and the position can be identified by the axial coordinate and the circumferential angle of the cylinder. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of a map generation method, a map generation device, and a surface inspection device according to the present disclosure will be described with reference to the drawings. The drawings are schematic and may differ from the actual device. Furthermore, the following embodiments exemplify devices or methods for embodying the technical ideas of the present disclosure, and are not intended to limit the configuration to those described below. In other words, the technical ideas of the present disclosure can be modified in various ways within the technical scope described in the claims.

[0014] In the present disclosure, the object 40 (see FIG. 3A, etc.) for which a two-dimensional map is to be generated is assumed to be a cylindrical or columnar three-dimensional object. In the following embodiment, a configuration example for generating a two-dimensional map of a surface 42 (see FIG. 3A, etc.) of the object 40 when the object 40 is a cylindrical three-dimensional object will be described.

[0015] (Example of map generation system 1 configuration) 1, a map generation system 1 according to an embodiment of the present disclosure includes a cart 10, a map generation device 20, and an inspection device 30. The cart 10 moves along a surface 42 of an object 40. The map generation device 20 generates a two-dimensional map that records the path traveled by the cart 10 along the surface 42.

[0016] The map generation system 1 does not necessarily have to include the inspection device 30. When the map generation system 1 includes the inspection device 30, it is also referred to as an inspection system. When the map generation system 1 includes the inspection device 30, the inspection device 30 inspects the surface 42 of the object 40 at least at one position along the path along which the cart 10 moves. The map generation device 20 reflects the result of the inspection of the surface 42 of the object 40 by the inspection device 30 in the two-dimensional map by associating it with the position of the cart 10 in the two-dimensional map.

[0017] <Cart 10> 1 and 2, the cart 10 includes a housing 11, a driving device 12, a movement amount measuring device 13, wheels 14, a sensor 15, and a control device 16. The cart 10 is magnetically attached to a surface 42 of an object 40 via the wheels 14, and the driving device 12 drives the wheels 14 to move along the surface 42 of the object 40.

[0018] The wheels 14 are attached to the housing 11. The wheels 14 are made of a material that generates a magnetic force. In this embodiment, the wheels 14 are magnetic wheels with built-in magnets. If the surface 42 of the object 40 is made of a magnetic material, the wheels 14 are magnetically attached to the surface 42 by the magnetic force. By magnetically attaching the wheels 14 to the surface 42, the housing 11 will not fall off the surface 42 even if the surface 42 faces in a direction other than vertically upward. Therefore, the cart 10 can be magnetically attached to the surface 42 and move along the surface 42 not only when the surface 42 of a cylindrical three-dimensional object faces vertically upward, but also when the surface 42 faces vertically downward.

[0019] The number of wheels 14 is not limited to four, and may be three or less, or five or more. The wheels 14 may be replaced with various other means such as caterpillars or crawlers (so-called Caterpillar (registered trademark)).

[0020] The means for attaching the wheel 14 to the surface 42 of the object 40 is not limited to magnetic attachment using magnetic force, but may include various other means such as attachment using a suction cup.

[0021] The drive unit 12 may include a power source such as a motor or an engine. The drive unit 12 is controlled by a control unit 16. The drive unit 12 may move the dolly 10 by rotating the wheels 14. The drive unit 12 is configured to be able to change the direction in which the dolly 10 moves by changing the direction of the wheels 14. In other words, the dolly 10 can move in any direction along the surface 42 while attached to the surface 42 by the wheels 14.

[0022] The driving device 12 may be configured to move the bogie 10 forward or backward. The direction in which the bogie 10 moves forward is also referred to as the reference direction D1. The direction in which the bogie 10 moves backward is the opposite direction to the reference direction. The driving device 12 may be configured to move the bogie 10 in a direction intersecting the reference direction D1. In this embodiment, the driving device 12 moves the bogie 10 forward, but does not move the bogie 10 backward or in a direction intersecting the reference direction D1.

[0023] The movement amount measuring device 13 may include, for example, an encoder. The encoder is an example of a distance measuring sensor. The encoder can measure the movement distance when the bogie 10 moves forward, that is, the movement amount of the bogie 10 along the reference direction D1, by measuring the rotation angle or number of rotations of the wheels 14 driven by the drive device 12, or the number of rotations of the motor or engine of the drive device 12.

[0024] The movement amount measuring device 13 may include a laser Doppler velocimeter, an optical flow sensor, or the like, instead of an encoder as a distance measuring sensor. When a laser Doppler velocimeter or an optical flow sensor is used as a distance measuring sensor, the influence of slippage due to gravity during movement of the dolly 10 is reduced compared to when an encoder is used. By reducing the influence of slippage, the accuracy of measuring the movement amount is improved. As a result, the accuracy of calculation is improved when calculating the position of the dolly 10 using the movement amount measurement results, as described below.

[0025] The sensor 15 is attached to the housing 11 of the dolly 10 and includes an accelerometer that measures the acceleration of the housing 11 and an angular velocity meter that measures the angular velocity of the housing 11. The accelerometer may include an acceleration sensor. The angular velocity meter may include a gyro sensor. The sensor 15 is configured to measure acceleration in the directions of each of the X1-axis, Y1-axis, and Z1-axis, and angular velocity around each of the X1-axis, Y1-axis, and Z1-axis.

[0026] Sensor 15 may be configured as an inertial measurement unit (IMU) that measures the acceleration and angular velocity of housing 11. An inertial measurement unit can detect three-dimensional inertial motion, including translational motion and rotational motion in three orthogonal axis directions, and corresponds to a device that combines an accelerometer and a gyroscope. When sensor 15 is configured as an inertial measurement unit, it can achieve higher measurement accuracy than when sensor 15 is configured with an accelerometer and a gyroscope separately.

[0027] The sensor 15 is installed on the cart 10 so that the X1-axis, Y1-axis, and Z1-axis, which measure acceleration and angular velocity, are aligned along predetermined directions. In this embodiment, the sensor 15 is installed on the cart 10 so that the normal direction of the surface 42 at the position where the housing 11 is magnetically attached coincides with the positive direction of the Z1-axis. The sensor 15 is also installed on the cart 10 so that the reference direction D1 of the cart 10 coincides with the negative direction of the Y1-axis. The sensor 15 is also installed on the cart 10 so that the direction of the cross product of a unit vector in the positive direction of the Y1-axis and a unit vector in the positive direction of the Z1-axis coincides with the positive direction of the X1-axis. In other words, the Z1-axis points toward the central axis of the cylindrical object 40. The X1-axis or the Y1-axis is included in the tangent plane of the surface 42 of the cylindrical object 40. In this embodiment, the X1-axis, Y1-axis, and Z1-axis form a so-called right-handed coordinate system.

[0028] The X1-axis, Y1-axis, and Z1-axis may be interchanged. Therefore, a measurement device combining an accelerometer and an angular velocity sensor, or an inertial measurement unit, may be arranged on the carriage 10 so that one of the three axes for measuring acceleration and angular velocity extends in the normal direction to the surface 42 of the object 40, and the other two axes are included in the tangent plane to the surface 42 of the object 40.

[0029] The sign of the angular velocity around the Z1 axis is positive in the clockwise direction toward the positive direction of the Z1 axis. Similarly, the sign of the angular velocity around the X1 axis is positive in the clockwise direction toward the positive direction of the X1 axis. The sign of the angular velocity around the Y1 axis is positive in the clockwise direction toward the positive direction of the Y1 axis.

[0030] The control device 16 acquires information or data from each component of the bogie 10 and controls the drive device 12 of the bogie 10 to move the bogie 10. The control device 16 may be configured to include at least one processor, such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The control device 16 may be configured with one processor or multiple processors. The processor constituting the control device 16 may control the traveling of the bogie 10 by reading and executing a program stored in a storage unit, which will be described later.

[0031] The control device 16 may include a storage unit. The storage unit stores various types of information or data. The storage unit may store, for example, a program executed by the control device 16, or data or processing results used in processing executed by the control device 16. The storage unit may also function as a work memory for the control device 16. The storage unit may include, but is not limited to, a semiconductor memory. For example, the storage unit may be configured as an internal memory of a processor used as the control device 16, or as a hard disk drive (HDD) accessible from the control device 16. The storage unit may be configured as a non-transitory readable medium. The storage unit may be configured integrally with the control device 16 or may be configured separately from the control device 16.

[0032] The control device 16 may include a communication unit. The communication unit may include a communication interface for communicating with other devices via a wired or wireless connection. The communication interface may be configured to communicate with other devices via a network. The communication unit may include an input / output port for inputting and outputting data to and from other devices. The communication unit transmits and receives necessary data and signals to and from a process computer or a higher-level system. The communication unit may communicate based on a wired communication standard or a wireless communication standard. The wired communication standard may include, for example, a communication standard such as USB (Universal Serial Bus), RS-232C, or RS-485. The wireless communication standard may include, for example, a communication standard such as IEEE 802.11 or Bluetooth (registered trademark), or a cellular phone communication standard such as 3G, 4G, or 5G. The communication unit may support one or more of these communication standards. The communication unit is not limited to these examples and may communicate with other devices or input and output data based on various standards. The communication unit may be configured integrally with the control device 16 or may be configured separately from the control device 16.

[0033] <Map Generation Device 20> As shown in Fig. 1, the map generating device 20 includes an acquisition unit 22, a generation unit 24, and an output unit 26. The map generating device 20 is assumed to be mounted on a carriage 10 as shown in Fig. 2. The map generating device 20 does not have to be mounted on the carriage 10.

[0034] The acquisition unit 22 acquires measurement results of acceleration and angular velocity from the sensor 15 of the cart 10, and acquires detection results of the movement amount of the cart 10 from the movement amount measurement device 13 of the cart 10. If the map generation system 1 includes an inspection device 30, the acquisition unit 22 acquires inspection results of the surface 42 from the inspection device 30.

[0035] The acquisition unit 22 may be configured to include a communication interface for communicating with other devices via a wired or wireless connection. The communication interface may be configured to communicate with other devices via a network. The communication unit may be configured to include an input / output port for inputting and outputting data to and from other devices. The communication unit transmits and receives necessary data and signals to and from a process computer or a higher-level system. The communication unit may communicate based on a wired communication standard or a wireless communication standard. The wired communication standard may include, for example, USB, RS-232C, or RS-485. The wireless communication standard may include, for example, IEEE 802.11 or Bluetooth (registered trademark), or a cellular phone communication standard such as 3G, 4G, or 5G. The acquisition unit 22 may support one or more of these communication standards. The acquisition unit 22 is not limited to these examples and may communicate with other devices or input and output data based on various standards. The acquisition unit 22 may be configured integrally with the generation unit 24 or separately from the generation unit 24.

[0036] The acquisition unit 22 may be configured to include an input device that accepts input of information or data from a person, such as a user, operating the map generation device 20. The input device may be configured to include, for example, a touch panel or a touch sensor, or a pointing device, such as a mouse. The input device may be configured to include physical keys. The input device may be configured to include an audio input device, such as a microphone. The acquisition unit 22 may be configured to be connectable to an external input device. The acquisition unit 22 may be configured to be able to acquire information or data input to the external input device from the external input device.

[0037] The generation unit 24 generates a two-dimensional map of the surface 42, which records the path of movement of the cart 10 along the surface 42 of the object 40. Furthermore, when the generation unit 24 acquires inspection results for the surface 42 from the inspection device 30, the generation unit 24 reflects the inspection results at points in the two-dimensional map that correspond to the positions where the surface 42 was inspected.

[0038] The generation unit 24 may be configured to include at least one processor, such as a CPU or a GPU. The generation unit 24 may be configured with one processor or multiple processors. The processor constituting the generation unit 24 may implement the functions of the map generation device 20 by reading and executing a program stored in a storage unit described below.

[0039] The generation unit 24 may include a storage unit. The storage unit stores various types of information or data used by the map generation device 20. The storage unit may store, for example, a program executed by the generation unit 24, or data or processing results used in the processing executed by the generation unit 24. The storage unit may also function as a work memory for the generation unit 24. The storage unit may include, for example, a semiconductor memory, but is not limited to this. For example, the storage unit may be configured as an internal memory of a processor used as the generation unit 24, or as a hard disk drive (HDD) accessible from the generation unit 24. The storage unit may be configured as a non-transitory readable medium. The storage unit may be configured integrally with the generation unit 24 or may be configured separately from the generation unit 24.

[0040] The output unit 26 may output or display the two-dimensional map generated by the generation unit 24 to an external device. Like the acquisition unit 22, the output unit 26 may be configured to include a communication interface for communicating with other devices via wired or wireless means. The output unit 26 may output the two-dimensional map to an external device through communication using the communication interface. The output unit 26 may be configured to include a display device that displays the two-dimensional map. The display device may be configured to include, for example, an LCD (Liquid Crystal Display), an organic EL (Electro-Luminescence) display or an inorganic EL display, or a PDP (Plasma Display Panel). The display device is not limited to these displays and may be configured to include various other types of displays.

[0041] <Inspection device 30> The inspection device 30 is mounted on the carriage 10 as shown in FIG. 2 . The inspection device 30 may include, for example, a surface flaw detector that detects flaws on the surface 42 of the object 40. The surface flaw detector may include equipment with a flaw detection function, such as an ultrasonic thickness gauge, an electromagnetic ultrasonic meter, an eddy current flaw detector, or a magnetic leakage flux flaw detector. By being mounted on the carriage 10, the surface flaw detector can perform flaw detection on the surface 42 while the carriage 10 moves along the surface 42. The surface flaw detector may, for example, detect flaws present on the surface 42, or, if the object 40 is a pipe, may detect thinning of the pipe. The inspection device 30 is not limited to a surface flaw detector and may include various other inspection devices.

[0042] The inspection device 30 may output the inspection results of the surface 42 in synchronization with the measurement results of the acceleration and angular velocity and the measurement results of the movement amount of the cart 10. For example, if the measurement results of the acceleration and angular velocity and the measurement results of the movement amount of the cart 10 are associated with the measurement time, the inspection device 30 may output the inspection results of the surface 42 in association with the inspection time. By synchronizing the inspection results of the surface 42 with the measurement results related to the movement of the cart 10, the inspection results can be easily associated with points on the movement path of the cart 10 recorded on the two-dimensional map generated by the map generation device 20.

[0043] The inspection device 30 may inspect the surface 42 while the carriage 10 is stationary. By identifying the position at which the carriage 10 is stationary, the inspection position on the surface 42 is identified. By identifying the inspection position on the surface 42, the inspection results can be easily associated with points on the movement path of the carriage 10 recorded on the two-dimensional map generated by the map generation device 20.

[0044] By associating the inspection positions on surface 42 with the inspection results, map generating device 20 can reflect the inspection results at points corresponding to the inspection positions on the two-dimensional map. In other words, map generating device 20 can reflect data including the positions of flaws detected on surface 42 on the two-dimensional map by performing flaw inspection on surface 42 while creating a two-dimensional map of surface 42 of the cylindrical three-dimensional object that is object 40. When reflecting the inspection results (inspection results) on the two-dimensional map, map generating device 20 may generate a color map as the two-dimensional map.

[0045] When a device that generates a large magnetic field, such as an eddy current flaw detector or a magnetic leakage flux flaw detector, is used as the flaw detection device, the sensor 15 that measures the acceleration and angular velocity of the bogie 10 may be composed of an element or equipment that is less affected by the magnetic field.

[0046] As described above, when the map generation system 1 includes the inspection device 30, it is also referred to as a surface inspection system. The surface inspection system generates a two-dimensional map by unfolding the surface 42 of the cylindrical three-dimensional object, which is the object 40, using the map generation device 20, inspects the surface 42 of the object 40 using the inspection device 30, and combines the inspection results with the two-dimensional map, thereby displaying the flaw detection results, i.e., the inspection results, on the two-dimensional map. By visually checking the flaw detection results, i.e., the inspection results, displayed on the two-dimensional map, the user can easily determine where the flaw detection point, i.e., the thinning point, is located on the surface 42 of the cylindrical three-dimensional object, which is the object 40.

[0047] (Example of operation of map generation system 1) In the map generation system 1 according to an embodiment of the present disclosure, the generation unit 24 of the map generation device 20 calculates the position of the dolly 10 on the surface 42 of the object 40 based on the information or data acquired by the acquisition unit 22. The generation unit 24 can generate a two-dimensional map that records the movement path of the dolly 10 on the two-dimensional plane by plotting points corresponding to the position of the dolly 10 on the two-dimensional plane that corresponds to the surface 42 of the object 40. An example of the operation of the generation unit 24 to generate a two-dimensional map will be described below.

[0048] <Two-dimensional plane obtained by developing the cylindrical surface, which is the surface 42 of the object 40> When the object 40 is a cylindrical three-dimensional object, the map generating device 20 may represent any position on the surface 42 of the object 40 using a cylindrical coordinate system. As shown in Fig. 3A, the position of any point in the cylindrical coordinate system can be uniquely identified by a Z-axis coordinate corresponding to the position in the axial direction of the cylinder, an r-axis coordinate corresponding to the position in the radial direction of the cylinder, and an angle θ corresponding to the position in the circumferential direction of the cylinder.

[0049] The surface 42 of the object 40 corresponds to a cylindrical surface. In a cylindrical surface, the radius is a constant value. That is, the r-axis coordinate corresponding to the position in the radial direction of the cylinder is a constant value. Therefore, any point located on the cylindrical surface 42 is uniquely identified by two parameters: the Z-axis coordinate corresponding to the position in the axial direction of the cylinder, and the angle θ corresponding to the position in the circumferential direction of the cylinder.

[0050] As shown in FIG. 3B, the cylindrical surface 42 is developed into a two-dimensional plane having a Z axis and a θ axis. In the two-dimensional plane of FIG. 3B, the Z axis is set as the horizontal axis, and the θ axis is set as the vertical axis. The θ axis is expressed in a range from −180° to +180°. For convenience, the two-dimensional plane developed into the cylindrical surface has an upper end and a lower end. In the two-dimensional plane developed into the cylindrical surface, the −180° angle at the upper end and the +180° angle at the lower end appear to be separated, but in reality, the −180° angle at the upper end and the +180° angle at the lower end are connected. The angles of the upper and lower ends of the two-dimensional plane are not limited to ±180° and may be set to any other angle, such as 0° or ±90°.

[0051] For example, as shown in Fig. 4A, assume that the cart 10 moves on the surface 42 of the target object 40, which is a cylindrical three-dimensional object, along a path 44 along the axial direction of the cylinder. In this case, the path 44 recorded on the two-dimensional plane on which the surface 42 is developed is represented by a combination of a path 441 that moves in the positive direction of the Z axis, which corresponds to the axial direction of the cylinder, and a path 442 that moves in the negative direction of the Z axis and also in the positive direction of the θ axis, as shown in Fig. 4B.

[0052] For example, as shown in FIG. 5A, assume that the cart 10 moves on the surface 42 of the target object 40, which is a cylindrical three-dimensional object, along a spiral path 45 along the circumferential direction of the cylinder. In this case, the path 45 recorded on the two-dimensional plane on which the surface 42 is unfolded is represented by a combination of paths 451 to 454, each extending from -180° to 180° along the θ axis, which corresponds to the circumferential direction of the cylinder, as shown in FIG. 5B. The Z coordinate of the lower end of path 451 coincides with the Z coordinate of the upper end of path 452. In other words, although the lower end of path 451 and the upper end of path 452 appear to be separated by the lower and upper ends, which are conveniently provided on the two-dimensional plane, they are actually connected. Similarly, the Z coordinate of the lower end of path 452 coincides with the Z coordinate of the upper end of path 453. The Z coordinate of the lower end of path 453 coincides with the Z coordinate of the upper end of path 454. That is, although the paths 451 to 454 appear to be disconnected at the bottom and top of the two-dimensional plane, they are actually connected as a single path.

[0053] <Determining the Position of the Cart 10 on the Surface 42 of the Object 40> When the object 40 is a cylindrical three-dimensional object, the position of the carriage 10 moving along the surface 42 of the object 40 is specified by an axial coordinate and a circumferential angle in a cylindrical coordinate system corresponding to the surface 42, which is a cylindrical surface. In other words, the position of the carriage 10 moving along the surface 42 of the object 40, which is a cylindrical three-dimensional object, is expressed as a point on a two-dimensional plane having a Z axis corresponding to the axial direction and a θ axis corresponding to the circumferential direction of the cylindrical coordinate system. The axial coordinate corresponds to the Z coordinate.

[0054] <<Calculation of the circumferential angle of the bogie 10>> The generation unit 24 of the map generation device 20 can calculate the circumferential angle of the bogie 10 based on the measurement results of the acceleration of the bogie 10. In this embodiment, the object 40 is assumed to be disposed so that the Z axis, which corresponds to the axial direction of the cylindrical surface corresponding to the surface 42 of the object 40, extends in a direction perpendicular to the vertical direction, i.e., along the horizontal direction.

[0055] If the trolley 10 is positioned at the top of the cylindrical surface that is the surface 42 of the object 40, that is, if the trolley 10 is positioned at a point where the circumferential angle is 0°, the Z1 axis along which the sensor 15 of the trolley 10 measures acceleration and angular velocity extends vertically upward.

[0056] Conversely, when the trolley 10 is positioned at the bottom of the cylindrical surface that is the surface 42 of the object 40, that is, when the trolley 10 is positioned at a point where the circumferential angle is +180° or -180°, the Z1 axis along which the sensor 15 of the trolley 10 measures acceleration and angular velocity extends vertically downward.

[0057] Furthermore, when the trolley 10 is positioned directly beside the cylindrical surface that is the surface 42 of the object 40, that is, when the trolley 10 is positioned at a point where the circumferential angle is +90° or -90°, the Z1 axis along which the sensor 15 of the trolley 10 measures acceleration and angular velocity extends in a direction perpendicular to the vertical direction, that is, along the horizontal direction.

[0058] When the bogie 10 is stationary or moving at a constant speed, the sensor 15 of the bogie 10 measures acceleration corresponding to the reaction force of gravity acting on the sensor 15. Gravity acts vertically downward. Conversely, the reaction force of gravity acts vertically upward. Therefore, the direction of acceleration corresponding to the reaction force of gravity is vertically upward. For example, when the Z1 axis along which the sensor 15 measures acceleration extends vertically upward, i.e., when the bogie 10 is located at a point with a circumferential angle of 0°, the absolute value of the acceleration along the Z1 axis measured by the sensor 15 matches the acceleration of gravity, and the sign of the acceleration along the Z1 axis is positive. Conversely, when the Z1 axis along which the sensor 15 measures acceleration extends vertically downward, i.e., when the bogie 10 is located at a point with a circumferential angle of +180° or -180°, the absolute value of the acceleration along the Z1 axis measured by the sensor 15 matches the acceleration of gravity, and the sign of the acceleration along the Z1 axis is negative.

[0059] When the bogie 10 is positioned at a point where the circumferential angle is +90° or -90°, the Z1 axis along which the sensor 15 measures acceleration extends horizontally. Therefore, the acceleration of the Z1 axis measured by the sensor 15 is 0. On the other hand, depending on the orientation of the sensor 15, at least one of the X1 axis or Y1 axis along which the sensor 15 measures acceleration has a vertical component.

[0060] When the reference direction D1 of the bogie 10 is along the circumferential direction, the Y1 axis on which the sensor 15 measures acceleration extends along the circumferential direction. Therefore, when the bogie 10 is located at a point where the circumferential angle is +90° or -90°, the Y1 axis extends vertically upward or downward. In this case, the absolute value of the acceleration on the Y1 axis measured by the sensor 15 matches the acceleration of gravity. The sign of the acceleration on the Y1 axis is positive when the Y1 axis extends vertically upward, and negative when the Y1 axis extends vertically downward.

[0061] When the reference direction D1 of the bogie 10 is along the axial direction, the Y1 axis, on which the sensor 15 measures acceleration, extends along the axial direction. In this case, the X1 axis, which is perpendicular to the Y1 axis, extends along the circumferential direction. Therefore, when the bogie 10 is located at a point where the circumferential angle is +90° or -90°, the X1 axis extends vertically upward or downward. In this case, the absolute value of the acceleration of the X1 axis measured by the sensor 15 matches the acceleration of gravity. The sign of the acceleration of the X1 axis is positive when the X1 axis extends vertically upward, and negative when the X1 axis extends vertically downward.

[0062] Furthermore, when the carriage 10 is positioned at a point where the circumferential angle is greater than 0° and less than +90°, the acceleration measured by the sensor 15 has a component on the Z1 axis and a component on at least one of the X1 axis and the Y1 axis.

[0063] As described above, there is a correlation between the circumferential angle of the bogie 10 and the acceleration measurement results of the sensor 15 of the bogie 10. Therefore, the generation unit 24 of the map generation device 20 can calculate the circumferential angle of the bogie 10 based on the acceleration measurement results of the sensor 15.

[0064] Hereinafter, a method for calculating the circumferential angle of the bogie 10 according to the orientation of the reference direction D1 at the initial position of the bogie 10 will be described.

[0065] <<<When the reference direction D1 of the carriage 10 is along the circumferential direction>>> As shown in Fig. 6A, the reference direction D1 of the cart 10 is set to the clockwise direction when the object 40 is viewed in the positive direction of the Z axis. In this case, the acceleration measured by the sensor 15 of the cart 10 is the Z1-axis component α z1 and the Y1 axis component α y1 The circumferential angle θ and the acceleration α of the Z1 axis are used to determine the circumferential position of the carriage 10. z1 and Y1-axis acceleration α y1 The relationship is expressed by the following formula (A1). θ=atan2(α z1 ,α y1 ) (A1) atan2 is the angle (α z1 ,α y1 ) as a component and the angle between the Z1 axis.

[0066] As shown in FIG. 6B, the reference direction D1 of the cart 10 is set to be counterclockwise around the object 40 when viewed in the positive direction of the Z axis. In this case, the acceleration measured by the sensor 15 of the cart 10 is also calculated by the Z1-axis component α z1 and the Y1 axis component α y1 The circumferential angle θ and the acceleration α of the Z1 axis are used to determine the circumferential position of the carriage 10. z1 and Y1-axis acceleration α y1 The relationship is expressed by the following formula (A2). θ=atan2(α z1 ,-α y1 ) (A2) The difference between equation (A1) and equation (A2) is the α input to the atan2 function. y1 This difference is due to the fact that the direction of the Y1 axis when the carriage 10 is positioned at a point where 0°<θ<180° is opposite between Figure 6A and Figure 6B.

[0067] <<<When the reference direction D1 of the carriage 10 is along the axial direction>>> As shown in Fig. 6C, the reference direction D1 of the cart 10 is set to the positive direction of the Z axis. In this case, the acceleration measured by the sensor 15 of the cart 10 is expressed by the Z1-axis component α z1 and the X1 axis component α x1 The circumferential angle θ and the acceleration α of the Z1 axis are used to determine the circumferential position of the carriage 10. z1 and acceleration α of the X1 axis x1 The relationship is expressed by the following formula (A3). θ=atan2(α z1 ,α x1 ) (A3) atan2 is the angle (α z1 ,α x1 ) as a component and the angle between the Z1 axis.

[0068] As shown in Fig. 6D, the reference direction D1 of the cart 10 is set to the negative direction of the Z axis. In this case, the acceleration measured by the sensor 15 of the cart 10 is also calculated by the Z1-axis component α z1 and the X1 axis component α x1 The circumferential angle θ and the acceleration α of the Z1 axis are used to determine the circumferential position of the carriage 10. z1 and acceleration α of the X1 axis x1 The relationship is expressed by the following formula (A4). θ=atan2(α z1 ,-α x1 ) (A4) The difference between equation (A3) and equation (A4) is the α input to the atan2 function. x1 This difference is due to the fact that the direction of the X1 axis when the carriage 10 is positioned at a point where 0°<θ<180° is opposite between Figure 6C and Figure 6D.

[0069] <<<Summary>>> As described above, the relationship between the acceleration measured by the sensor 15 and the circumferential angle varies depending on the direction in the cylindrical coordinate system representing the surface 42 of the object 40 that the reference direction D1 of the bogie 10 faces. The generation unit 24 may select a formula for calculating the circumferential angle from the acceleration measurement results in accordance with the reference direction D1 of the bogie 10. The formula for calculating the circumferential angle from the acceleration measurement results is also referred to as a first map conversion formula. Specifically, the generation unit 24 may calculate the circumferential angle of the bogie 10 by applying the acceleration measurement results of the bogie 10 to the first map conversion formula. The first map conversion formula may be prepared in advance in the map generation device 20.

[0070] When the reference direction D1 of the bogie 10 has a circumferential component and an axial component, the generation unit 24 may calculate the circumferential angle by combining a formula used when the reference direction D1 of the bogie 10 is circumferential and a formula used when the reference direction D1 of the bogie 10 is axial.

[0071] The generation unit 24 may select formula (A1) to be used when the reference direction D1 of the bogie 10 is clockwise circumferentially, if the inclination of the reference direction D1 of the bogie 10 is within a predetermined angle with respect to the clockwise circumferential direction. The generation unit 24 may select formula (A2) to be used when the reference direction D1 of the bogie 10 is counterclockwise circumferentially, if the inclination of the reference direction D1 of the bogie 10 is within a predetermined angle with respect to the counterclockwise circumferential direction. The generation unit 24 may select formula (A3) to be used when the reference direction D1 of the bogie 10 is the positive direction of the Z axis, if the inclination of the reference direction D1 of the bogie 10 is within a predetermined angle with respect to the positive direction of the Z axis. The generation unit 24 may select formula (A4) to be used when the reference direction D1 of the bogie 10 is the negative direction of the Z axis, if the inclination of the reference direction D1 of the bogie 10 is within a predetermined angle with respect to the negative direction of the Z axis. The predetermined angle may be set to a value less than 45°.

[0072] <<Calculation of the axial coordinate of the bogie 10>> The generation unit 24 of the map generation device 20 can calculate the reference direction D1 of the carriage 10 at any time based on the reference direction D1 at the initial position of the carriage 10 and the angular velocity measurement results obtained by the sensor 15 of the carriage 10.

[0073] As described above, in this embodiment, the Z1 axis along which the sensor 15 of the dolly 10 measures angular velocity is determined so that the normal direction of the surface 42 at the position where the housing 11 of the dolly 10 is magnetically attached coincides with the positive direction of the Z1 axis. The reference direction D1 of the dolly 10 is along the tangential direction of the surface 42. When the dolly 10 rotates around the Z1 axis, the reference direction D1 of the dolly 10 rotates around the Z1 axis. The generation unit 24 can calculate, as the reference direction D1 of the dolly 10 at any time, a direction obtained by rotating the reference direction D1 at the initial position of the dolly 10 by an angle calculated by integrating the angular velocity around the Z1 axis.

[0074] The generation unit 24 can calculate the axial movement amount of the bogie 10 based on the angle of the reference direction D1 of the bogie 10 with respect to the axial direction of the cylindrical coordinate system and the measurement result of the movement amount by the movement amount measurement device 13 of the bogie 10. The generation unit 24 can calculate the axial coordinate of the bogie 10 by adding the axial movement amount of the bogie 10 to the axial coordinate at the initial position of the bogie 10. The generation unit 24 may calculate the axial coordinate of the bogie 10 by assuming that the axial coordinate at the initial position of the bogie 10 is 0. The generation unit 24 may calculate the axial movement amount of the bogie 10 as the axial movement distance from the initial position of the bogie 10.

[0075] Hereinafter, a method for calculating the axial coordinate of the bogie 10 according to the orientation of the reference direction D1 of the bogie 10 will be described.

[0076] <<<When the reference direction D1 at the initial position of the carriage 10 is along the circumferential direction>>> As shown in FIG. 7A, the reference direction D1 of the carriage 10 is the clockwise direction when the object 40 is viewed in the positive direction of the Z axis, that is, the angle θ from the positive direction of the θ axis. z1 In FIG. 7A, the Z1 axis, on which the sensor 15 of the cart 10 measures angular velocity, is assumed to be pointing towards the front of the page. Therefore, the counterclockwise angle is positive. Since the counterclockwise angle is positive, the angle by which the reference direction D1 is tilted counterclockwise from the θ axis is θ. z1It is expressed as:

[0077] Angle θ of the reference direction D1 of the carriage 10 z1 is the angular velocity ω about the Z1 axis measured by the sensor 15 of the carriage 10. z1 The angular velocity ω is calculated as the integrated value of z1 The time for integrating is the travel time t of the carriage 10. In this case, the angle θ z1 is θ z1 =Σ(ω z1 × t) and the angle θ z1 may be calculated by integrating the angular velocity over time.

[0078] When the movement amount of the carriage 10 along the reference direction D1 is L, the generation unit 24 calculates the movement amount L in the Z-axis direction. z can be calculated using the following formula (B1). L z =L×sin(θ z1 ) (B1)

[0079] As shown in FIG. 7B, the reference direction D1 of the carriage 10 is the counterclockwise direction around the circumferential direction when the object 40 is viewed in the positive direction of the Z axis, that is, the angle −θ z1 When the movement amount of the dolly 10 along the reference direction D1 is L, the generation unit 24 calculates the movement amount L in the Z-axis direction. z can be calculated using the following formula (B2). L z =L×sin(-θ z1 ) (B2) Equation (B2) may be transformed into the following equation: L z =-L×sin(θ z1 )

[0080] <<<When the reference direction D1 at the initial position of the carriage 10 is along the axial direction>>> As shown in FIG. 7C, the reference direction D1 of the carriage 10 is at an angle θ z1 When the movement amount of the dolly 10 along the reference direction D1 is L, the generation unit 24 calculates the movement amount L in the Z-axis direction. zcan be calculated using the following formula (B3). L z =L×cos(θ z1 ) (B3)

[0081] As shown in FIG. 7D, the reference direction D1 of the carriage 10 is angled θ z1 When the movement amount of the dolly 10 along the reference direction D1 is L, the generation unit 24 calculates the movement amount L in the Z-axis direction. z can be calculated using the following formula (B4). L z =-L×cos(θ z1 ) (B4)

[0082] <<<Summary>>> As described above, the generation unit 24 may select a formula for calculating the amount of movement in the axial direction based on the measurement results of the angular velocity and the measurement results of the amount of movement of the bogie 10 along the reference direction D1, depending on the orientation of the bogie 10 in the reference direction D1. The formula for calculating the amount of movement in the axial direction is also referred to as a second map conversion formula. Specifically, the generation unit 24 may apply the measurement results of the angular velocity around the Z1 axis to the second map conversion formula to calculate the rotation angle around the Z1 axis from the initial position of the bogie 10, and calculate the reference direction D1 of the bogie 10. The second map conversion formula may be prepared in advance in the map generation device 20.

[0083] The generation unit 24 may select formula (B1) to calculate the axial movement amount of the bogie 10 when the inclination of the reference direction D1 of the bogie 10 is within a predetermined angle with respect to the clockwise circumferential direction. The generation unit 24 may select formula (B2) to calculate the axial movement amount of the bogie 10 when the inclination of the reference direction D1 of the bogie 10 is within a predetermined angle with respect to the counterclockwise circumferential direction. The generation unit 24 may select formula (B3) to calculate the axial movement amount of the bogie 10 when the inclination of the reference direction D1 of the bogie 10 is within a predetermined angle with respect to the positive direction of the Z axis. The generation unit 24 may select formula (B4) to calculate the axial movement amount of the bogie 10 when the inclination of the reference direction D1 of the bogie 10 is within a predetermined angle with respect to the negative direction of the Z axis. The predetermined angle may be set to a value less than 45°.

[0084] The generation unit 24 may select any one of the formulas (B1) to (B4), regardless of whether the inclination of the reference direction D1 of the bogie 10 is closer to the circumferential direction or the axial direction. Regardless of which of the formulas (B1) to (B4) is selected, the generation unit 24 can appropriately calculate the amount of movement of the bogie 10 in the axial direction by appropriately calculating the angle representing the inclination of the reference direction D1 of the bogie 10 in each formula.

[0085] The generation unit 24 may calculate the axial coordinate of the bogie 10 by adding the calculation result of the amount of movement of the bogie 10 in the axial direction to the axial coordinate of the bogie 10 at its initial position.

[0086] <Generation of a 2D map of the movement path of the cart 10> As described above, the generation unit 24 of the map generation device 20 can calculate the circumferential angle and the axial coordinate of the bogie 10 as information for specifying the position of the bogie 10. The generation unit 24 may calculate the circumferential angle and the axial coordinate of the bogie 10 at any time based on the measurement results of the sensor 15 and the measurement results of the movement amount measurement device 13 while the bogie 10 is moving. The generation unit 24 may calculate the circumferential angle and the axial coordinate of the bogie 10 at regular time intervals, or may calculate the circumferential angle and the axial coordinate of the bogie 10 at irregular time intervals.

[0087] The generation unit 24 can generate a two-dimensional map of the movement path of the bogie 10 by plotting the calculation results of the circumferential angle and axial coordinate of the bogie 10 at each of multiple times on a two-dimensional plane having a Z axis and a θ axis.

[0088] The generator 24 may generate a two-dimensional map, for example, shown in FIG. 8, in which the measurement results of the position of the carriage 10 are plotted and recorded as a solid line on a two-dimensional plane having a Z axis and a θ axis. The two-dimensional map of FIG. 8 was generated by magnetically attaching the carriage 10 to the surface of an 1800A pipe, moving it axially to the right, and reversing the movement direction every 1000 mm of axial movement. In the two-dimensional map of FIG. 8, the points indicated by solid circles (●) correspond to the true positions of the carriage 10. The solid line plotting the measurement results has an error of within ±5° in the circumferential angle of the θ axis and within ±10% in the axial coordinate of the Z axis, relative to the true position of the carriage 10 indicated by the solid circle. In other words, the map generator 20 according to this embodiment has been shown to have sufficient mapping accuracy.

[0089] When generating the map, the generation unit 24 may acquire measurement results of angular velocity around each of the X1-axis, Y1-axis, and Z1-axis at the initial position of the bogie 10. In order to suppress drift error of the inertial measurement unit or the angular velocity meter, the generation unit 24 may acquire measurement results of angular velocity around the Z1-axis when the bogie 10 is in a stationary state as calibration, and calculate the average value of the angular velocity measurement results over 10 seconds as the drift error. The generation unit 24 may use a value obtained by subtracting the drift error from the measurement results of the angular velocity around the Z1-axis as the value of the angular velocity around the Z1-axis to be applied to the map conversion formula.

[0090] <Reflecting surface inspection results on a 2D map> The generation unit 24 of the map generation device 20 may acquire the inspection results of the surface 42 of the object 40 from the inspection device 30. The generation unit 24 may associate the position of the cart 10 with the inspection results of the surface 42 at that position, and reflect the inspection results of the surface 42 at the corresponding position on a two-dimensional map that records the movement path of the cart 10. In other words, when the cart 10 moves to a predetermined position, the inspection device 30 may inspect the surface at the predetermined position. The generation unit 24 may reflect the inspection results of the surface 42 at the predetermined position on a point on the two-dimensional map that corresponds to the predetermined position.

[0091] For example, when flaw detection is performed on the surface 42 as the inspection of the surface 42, the generation unit 24 may reflect defects such as the positions of scratches or thinning that exist on the surface 42 in the two-dimensional map. When the generation unit 24 reflects the inspection results in the two-dimensional map, the generation unit 24 may generate the two-dimensional map as a color map.

[0092] In the map generation system 1 according to this embodiment, the map generation device 20 is combined with the inspection device 30, so that the inspection results of the surface 42 by the inspection device 30 are reflected and displayed on a two-dimensional map. By displaying the inspection results of the surface 42, it becomes easy to visually determine where defects such as flaw detection points or thinning points exist on the surface 42 of the object 40.

[0093] <Example of map generation procedure> The generation unit 24 of the map generation device 20 may execute a map generation method including the steps of the flowchart illustrated in Fig. 9. The map generation method may be realized as a map generation program executed by a processor included in the generation unit 24. The map generation program may be stored in a non-transitory computer-readable medium.

[0094] The generation unit 24 acquires a reference direction D1 at the initial position of the bogie 10 (step S1). The generation unit 24 selects a first map conversion formula and a second map conversion formula depending on whether the reference direction D1 is along the circumferential direction or the axial direction (step S2). The procedure of step S2 is also referred to as a map conversion formula selection step.

[0095] The generation unit 24 acquires the measurement results of the acceleration and angular velocity of the cart 10 (step S3). The generation unit 24 acquires the measurement results of the movement amount of the cart 10 along the reference direction D1 (step S4). The procedures of steps S3 and S4 are also referred to as an acquisition step.

[0096] The generation unit 24 applies the measurement result of the acceleration of the bogie 10 to the first map conversion formula selected in the procedure of step S2, and calculates the circumferential angle of the bogie 10 (step S5). The procedure of step S5 is also referred to as a circumferential angle calculation step.

[0097] The generation unit 24 applies the angle of the reference direction D1 of the bogie 10 with respect to the θ-axis or the Z-axis and the measurement results of the movement amount of the bogie 10 to the second map conversion formula selected in the procedure of step S2, and calculates the movement amount of the bogie 10 in the axial direction (step S6). In the procedure of step S6, the generation unit 24 may recalculate the angle of the reference direction D1 of the bogie 10 with respect to the θ-axis or the Z-axis based on the measurement results of the angular velocity of the bogie 10.

[0098] The generation unit 24 calculates the axial coordinate of the bogie 10 by adding the axial movement amount of the bogie 10 calculated in the procedure of step S6 to the axial coordinate of the initial position of the bogie 10 (step S7). The procedure of step S7 is also referred to as an axial coordinate calculation step.

[0099] The generation unit 24 plots the position of the bogie 10, which is specified by the circumferential angle of the bogie 10 calculated in the procedure of step S5 and the axial coordinate of the bogie 10 calculated in the procedure of step S7, on a two-dimensional plane having a θ axis and a Z axis, and generates a two-dimensional map that records the movement path of the bogie 10 (step S8). The procedure of step S8 is also referred to as a map generation step.

[0100] The generation unit 24 determines whether the inspection results of the surface 42 have been acquired from the inspection device 30 (step S9). If the inspection results of the surface 42 have not been acquired (step S9: NO), the generation unit 24 ends the execution of the procedure in the flowchart of FIG. 9. If the inspection results of the surface 42 have been acquired (step S9: YES), the generation unit 24 reflects the inspection results of the surface 42 in points in the two-dimensional map that correspond to the positions where the inspection was performed (step S10). After executing the procedure in step S10, the generation unit 24 ends the execution of the procedure in the flowchart of FIG. 9.

[0101] After completing the procedure of step S10, the generation unit 24 may return to the procedure of step S1 and repeat the calculation of the position of the bogie 10 and the generation of the two-dimensional map. In the procedure of step S1, the generation unit 24 may acquire the reference direction D1 of the bogie 10, using the position of the bogie 10 calculated in the procedures of steps S5 and S7 as a new initial position.

[0102] (summary) As described above, according to the map generating device 20 and map generating method of this embodiment, by using two map conversion formulas including a formula for calculating a circumferential angle and a formula for calculating an axial coordinate, the circumferential angle and the axial coordinate of the bogie 10 moving along the surface 42 of the cylindrical object 40 are calculated based on the measurement results of the acceleration and angular velocity of the bogie 10 and the measurement results of the travel distance.

[0103] The map conversion formula is selected depending on the orientation of the reference direction D1 of the bogie 10. Specifically, when the bogie 10 moves in the circumferential direction from the initial position, it moves in a spiral on the surface 42 of the cylindrical object 40. When the bogie 10 moves in the axial direction from the initial position, it moves by turning around on the surface of the cylindrical object 40. Therefore, the generation unit 24 of the map generation device 20 may select the map conversion formula depending on whether the reference direction D1 of the bogie 10 is oriented clockwise or counterclockwise in the circumferential direction, or whether the reference direction D1 of the bogie 10 is oriented in the positive or negative axial direction.

[0104] In addition, by plotting the calculation results of the circumferential angle and axial coordinates of the bogie 10 on a two-dimensional plane having the θ axis and the Z axis, a two-dimensional map recording the movement path of the bogie 10 is generated.

[0105] That is, a two-dimensional map recording the movement path of the bogie 10 is generated based on the measurement results of the acceleration and angular velocity of the bogie 10 and the measurement results of the movement distance. Therefore, according to the map generation device 20 and map generation method of this embodiment, a two-dimensional map is generated without inputting the diameter of the cylindrical object 40. As a result, even if the diameter of the cylindrical object 40 is unknown, a two-dimensional map recording the movement path of the bogie 10 can be generated easily and accurately.

[0106] In particular, in the above-described embodiment, a map conversion formula is selected according to the reference direction D1 at the initial position of the bogie 10, so that a two-dimensional map recording the movement path of the bogie 10 can be easily and accurately generated regardless of the direction in which the bogie 10 moves, including the circumferential direction or the axial direction.

[0107] (Variation) In the above-described embodiment, the angle θ corresponding to the circumferential position of the cylinder illustrated in FIG. 3A and the θ-axis in the two-dimensional plane having the Z-axis and the θ-axis illustrated in FIG. 3B are expressed in the range of −180° to +180°. Here, the angle θ corresponding to the circumferential position of the cylinder and the θ-axis in the two-dimensional plane are not limited to the above example and may be expressed in other ranges of values. For example, as shown in FIGS. 10A and 10B, the angle θ corresponding to the circumferential position of the cylinder and the θ-axis in the two-dimensional plane may be expressed in the range of 0° to 360°.

[0108] In the two-dimensional plane obtained by unfolding the cylindrical surface, the upper end (0°) and the lower end (360°) are separated, but in reality, the upper end (0°) and the lower end (360°) are connected. The angles of the upper and lower ends of the two-dimensional plane are not limited to 0° and 360°, and may be set to any other angle, such as 90°, 180°, or 270°.

[0109] When the angle θ and the θ axis are expressed in the range from 0° to 360°, the above-described first map conversion formulas (A1) to (A4) are replaced with the following formulas (A1′) to (A4′). θ=atan2(-α z1 ,-αy1 ) (A1') θ=atan2(-α z1 ,α y1 ) (A2') θ=atan2(-α z1 ,-α x1 ) (A3') θ=atan2(-α z1 ,α x1 ) (A4')

[0110] Moreover, the above-mentioned second map conversion formulas (B1) to (B4) can be replaced with the following formulas (B1') to (B4'). Lz = L × sin(θ z1 ) (B1') Lz = L × sin(-θ z1 ) (B2') Lz = L × cos(θ z1 ) (B3') Lz = -L × cos(θ z1 ) (B4')

[0111] As explained as a modified example, even if the expression of the angle θ and the numerical range of the θ axis is changed, it is possible to calculate the circumferential angle and axial coordinate of the bogie 10 in the same way as in the above-described embodiment.

[0112] Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art could make various modifications or alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are included within the scope of the present disclosure. For example, the functions included in each component or step can be rearranged so as not to cause logical inconsistencies, and multiple components or steps can be combined or divided into one. The embodiments of the present disclosure can also be realized as a program executed by a processor included in an apparatus or a storage medium on which a program is recorded. It should be understood that these are also included within the scope of the present disclosure.

[0113] Furthermore, in the above-described embodiment, a configuration example has been described in which a two-dimensional map of the outer peripheral surface of a cylinder is generated as surface 42 of object 40. However, surface 42 of object 40 is not limited to the outer peripheral surface of a cylinder, and a two-dimensional map of the inner peripheral surface of a cylinder may also be generated. When cart 10 moves on the inner peripheral surface of a cylinder, the orientation of cart 10, i.e., the axis of sensor 15, is reversed compared to when cart 10 moves on the outer peripheral surface of a cylinder. Therefore, by reversing the signs of at least some of the parameters, such as acceleration, included in the map conversion formula described above, it is possible to generate a two-dimensional map of the inner peripheral surface of a cylinder. [Explanation of symbols]

[0114] 1. Map Generation System 10 Cart (11: Housing, 12: Drive unit, 13: Movement amount measuring device, 14: Wheel, 15: Sensor, 16: Control device) 20 map generating device (22: acquisition unit, 24: generation unit, 26: output unit) 30 Inspection equipment 40 Object (42: Surface) 44, 441, 442, 45, 451-454 Travel route

Claims

1. A map generation method for generating a two-dimensional map of a movement path of a cart moving on a surface of a cylindrical or columnar three-dimensional object, comprising: an acquisition step of acquiring measurement results of the acceleration and angular velocity of the carriage and measurement results of the movement distance of the carriage along the surface of the three-dimensional object while the carriage moves along the surface of the three-dimensional object; a circumferential angle calculation step of calculating the circumferential angle of the bogie on the surface of the three-dimensional object by applying the acceleration measurement results acquired in the acquisition step to a first map conversion formula, which is a mathematical formula for calculating the circumferential angle of the bogie from the acceleration measurement results of the bogie, and which is selected depending on the direction of a reference direction, which is the direction in which the bogie moves forward; an axial coordinate calculation step of calculating an axial movement amount of the bogie by applying the angular velocity measurement result and the movement distance measurement result acquired in the acquisition step to a second map conversion formula, which is a mathematical formula for calculating an axial movement amount of the bogie based on the angular velocity measurement result of the bogie and the movement distance measurement result of the bogie, and which is selected depending on the direction of the reference direction, and calculating an axial coordinate of the bogie on the surface of the three-dimensional object by adding the calculated axial movement amount of the bogie to an axial coordinate of the bogie at an initial position; a map generating step of generating a two-dimensional map in which positions specified by the circumferential angle calculated in the circumferential angle calculating step and the axial coordinate calculated in the axial coordinate calculating step are recorded; A map generation method including:

2. The map generating method according to claim 1 , further comprising a map transformation formula selection step of selecting the first map transformation formula and the second map transformation formula based on a reference direction at an initial position of the carriage moving on the surface of the three-dimensional object.

3. a generating unit that generates a two-dimensional map of a movement path of a carriage that moves on a surface of a cylindrical or columnar three-dimensional object; an acquisition unit that acquires measurement results of the acceleration and angular velocity of the carriage and measurement results of the movement distance of the carriage along the surface of the three-dimensional object; Equipped with The generation unit calculating a circumferential angle of the bogie on the surface of the three-dimensional object by applying the measurement result of the acceleration of the bogie to a first map conversion formula, which is a formula for calculating a circumferential angle of the bogie from the measurement result of the acceleration of the bogie, and which is selected depending on the direction of a reference direction, which is the direction in which the bogie moves forward; calculating an axial movement amount of the bogie by applying the measurement results of the angular velocity of the bogie and the measurement results of the movement distance of the bogie to a second map conversion formula, which is a formula for calculating an axial movement amount of the bogie based on the measurement results of the angular velocity of the bogie and the measurement results of the movement distance of the bogie, and which is selected depending on the direction of the reference direction; and calculating an axial movement amount of the bogie on the surface of the three-dimensional object by adding the calculated axial movement amount of the bogie to an axial coordinate of the bogie at an initial position; generating a two-dimensional map recording positions identified by the circumferential angle of the bogie and the axial coordinate of the bogie; Map generator.

4. The map generating device of claim 3 , further comprising an accelerometer for measuring the acceleration of the carriage, and an angular velocity meter for measuring the angular velocity of the carriage.

5. The map generating device according to claim 3 , further comprising an inertial measurement unit that measures three-axial acceleration and angular velocity of the carriage.

6. 6. The map generating device according to claim 5, wherein the inertial measurement unit is arranged on the cart so that one of the three axes for measuring acceleration and angular velocity extends in the normal direction of the three-dimensional object, and the other two axes are included in a tangent plane to the surface of the three-dimensional object.

7. a map generating device according to any one of claims 3 to 6; and an inspection device that inspects a surface at a predetermined position when the carriage moves to the predetermined position; A surface inspection apparatus, wherein the generation unit of the map generation device reflects the inspection result of the surface at the predetermined position in a point corresponding to the predetermined position in a two-dimensional map.

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