JP2013024735A - Mobile body and movement surface detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the position and posture of a mobile body moving on a movement surface with low contrast and also the shape of the movement surface under an environment with low illuminance.SOLUTION: A mobile body and movement surface detection system 1 includes: a mobile body 3; a light emission part 4 arranged on the mobile body 3; a stereo camera 5 and a ranging sensor 6 which are arranged at positions to look down at the mobile body 3; a processing part 7 for processing the outputs of the stereo camera 5 and the ranging sensor 6; and a display part 8 for displaying the output of the processing part 7. The stereo camera 5 captures the stereo image of the light emission part 4. The ranging sensor 6 emits light toward the movement surface and ranges the movement surface on the basis of the flight time of light to be returned after reflection against the movement surface. The processing part 7 detects the position and posture of the mobile body 3 on the basis of the stereo image captured by the stereo camera 5 and detects the shape of the movement surface on the basis of the output of the ranging sensor 6. The display part 8 displays the position and posture of the mobile body 3 and the shape of the movement surface.

Description

  The present invention relates to a system for detecting the position and posture of a moving body such as a robot and the shape of a moving surface on which the moving body moves.

  Conventionally, refining is performed in a refinery by hydrodesulfurizing crude oil in a reaction furnace. A granular catalyst is used for this treatment. As shown in FIG. 5, the reaction furnace 2 has an in-furnace floor surface 22 through which oil permeates and the catalyst does not pass. The furnace floor 22 has holes 23 through which the catalyst passes. On the in-furnace floor surface 22, a slope of the residual catalyst 24 forming an angle of repose around the hole 23 is formed. In order to discharge the remaining catalyst 24 to the outside of the reaction furnace 2, a ladder 25 is temporarily installed in the reaction furnace 2 from the upper opening of the reaction furnace 2, and an operator enters the reaction furnace 2 to break the slope of the remaining catalyst 24. Is discharged from the hole 23. The discharged catalyst is recovered and regenerated.

  In the reaction furnace 2, there are substances such as volatile oil and hydrogen that may cause an explosion or fire. In order to prevent an explosion or a fire, the reactor 2 may be filled with nitrogen at the time of work to be made oxygen-free. Further, the inside of the reaction furnace 2 is dim and dust is standing up, and the visibility is not good. Thus, the working environment in the reaction furnace 2 is very severe. Prior to work in the reaction furnace 2, the remaining catalyst 24 may be immersed in water. In this case, the entire reactor 2 is filled with water, and water is drained after a predetermined time. Thereby, the inside of the reaction furnace 2 is washed, and the catalyst remaining in the reaction furnace 2 is in a state containing water. If the catalyst contains water, explosions and fires are prevented and dust is reduced. Further, even if oxygen is put into the reaction furnace 2, heat generation of the catalyst can be suppressed, so that an oxygen deficiency operation by an operator is avoided. However, the catalyst containing water cannot be regenerated. Since the catalyst is expensive, when water is sprayed on the remaining catalyst 24, the cost of refining crude oil increases significantly.

  In order to relieve workers from harsh work in the reactor 2, it is desired to develop and introduce a robot for unmanned work. Since this robot moves on an unstable slope composed of the remaining catalyst 24, it is necessary to detect not only the position of the robot but also its posture. Moreover, since the slope which is the movement surface 21 deform | transforms with the movement and operation | work of a robot, it is necessary to detect shapes, such as an inclination of the movement surface 21, an unevenness | corrugation.

  In general, a moving robot is equipped with a visible light video camera and grasps the surrounding situation and the self-position based on an image captured by the mounted video camera. However, since the illuminance is low in the reaction furnace 2 and the moving surface 21 made of the remaining catalyst 24 is a monotone with extremely low contrast, the position of the robot and the shape of the moving surface 21 can be grasped with a video camera mounted on the robot. Is difficult.

  2. Description of the Related Art A device is known in which a plurality of light emitting diodes are provided on a moving object (moving body), the light emitting diodes are photographed with three fixed cameras, and the position and orientation of the object are detected based on the photographed images. (For example, refer to Patent Document 1). However, since the illuminance is low in the reactor 2 and the moving surface 21 is monotone, even if the moving surface 21 is photographed with such an apparatus, the shape of the moving surface 21 cannot be detected.

JP 2004-50356 A

  An object of the present invention is to solve the above-described problem and to detect the position and posture of a moving body that moves on a moving surface with low contrast and the shape of the moving surface in an environment with low illuminance.

  The moving body and the moving surface detection system of the present invention include a moving body that moves on the moving surface, a light emitting unit that includes three or more point light sources arranged on the moving body, and a position overlooking the moving body. A stereo camera and a distance sensor, a processing unit that processes the output of the stereo camera and the distance sensor, and a display unit that displays the output of the processing unit, the stereo camera including the light emitting unit The distance measuring sensor emits light to the moving surface, measures the distance of the moving surface based on the flight time of the light reflected and returned by the moving surface, and the processing unit The position and orientation of the moving object are detected based on the stereo image captured by the stereo camera, and the shape of the moving surface is detected based on the output of the distance measuring sensor, and the position and orientation of the moving object and the shape of the moving surface are detected. Is displayed on the display section. Characterized in that it.

  In the moving body and the moving surface detection system, it is preferable that each of the point light sources emits light having a wavelength range different from the wavelength of light emitted from the distance measuring sensor while having different spectral distributions.

  In the moving body and moving surface detection system, it is preferable that the moving body and the moving surface detection system include an operation unit that remotely controls the movement of the moving body.

  In the moving body and moving surface detection system, it is preferable that the moving body autonomously moves based on the position and posture of the moving body detected by the processing unit and the shape of the moving surface.

  According to the present invention, since the stereo camera captures a stereo image of the light emitting unit that emits light, the stereo image can be captured even in a low illuminance environment, and the position and orientation of the moving object can be detected based on the stereo image. it can. Since the distance measuring sensor measures the moving surface based on the flight time of light, the shape of the moving surface can be detected even when the contrast of the moving surface is low.

The block block diagram of the mobile body and moving surface detection system which concern on one Embodiment of this invention. Sectional drawing of the reactor provided with the system. The perspective view of the moving body in the system. The figure explaining calculation of the position of the point light source in the system. Sectional drawing of the conventional reactor.

  A moving body and a moving surface detection system (hereinafter referred to as a detection system) according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, in the present embodiment, the detection system 1 is used in a reaction furnace 2. The detection system 1 includes a moving body 3 that moves on a moving surface 21, a light emitting unit 4 disposed on the moving body 3, a stereo camera 5, and a distance measuring sensor 6 in the reaction furnace 2. The light emitting unit 4 includes three or more point light sources 41. In the present embodiment, the number of point light sources 41 is three. The stereo camera 5 and the distance measuring sensor 6 are provided at a position overlooking the moving body 3. The detection system 1 includes a processing unit 7 and a display unit 8 outside the reaction furnace 2. The processing unit 7 processes the outputs of the stereo camera 5 and the distance measuring sensor 6. The display unit 8 displays the output of the processing unit 7.

  The stereo camera 5 captures a stereo image of the light emitting unit 4. The distance measuring sensor 6 emits light to the moving surface 21 and measures the distance of the moving surface 21 based on the flight time of the light reflected by the moving surface 21 and returning. The processing unit 7 detects the position and orientation of the moving body 3 based on the stereo image captured by the stereo camera 4, and detects the shape of the moving surface 21 based on the output of the distance measuring sensor 6. The posture of the moving body 3 is the orientation of the moving body 3 in the three-dimensional space, and is represented by, for example, the angle of yaw, pitch, and roll. The shape of the moving surface 21 is the inclination and unevenness of the moving surface 21, the boundary of the moving surface 21 with the wall surface of the reactor 2, and the like. The processing unit 7 displays the position and posture of the moving body 3 and the shape of the moving surface 21 on the display unit 8.

  The reaction furnace 2 is, for example, a furnace that hydrotreats crude oil. The reaction furnace 2 is filled with a granular catalyst. The reaction furnace 2 has an in-furnace floor surface 22 through which oil passes and the catalyst does not pass through. The furnace floor 22 has holes 23 through which the catalyst passes. The catalyst filled in the reaction furnace 2 is discharged out of the reaction furnace 2 by natural dropping from the hole 23. On the in-furnace floor surface 22, a slope of the residual catalyst 24 forming an angle of repose around the hole 23 is formed. This slope is the moving surface 21 of the moving body 3. The moving surface 21 is unstable, and its shape changes as the moving body 3 moves on it.

  The moving body 3 is a robot that moves while pushing the remaining catalyst 24, and as shown in FIG. 3, the main body 31, the crawlers 32 provided on the left and right sides of the main body 31, and the blade provided on the front part. 33, a headlamp 34, and a video camera 35 for monitoring the front. The upper part of the moving body 3 is protected by a protective frame 36. The moving body 3 is moved by driving a crawler 32 by a driving device built in the main body 31 and pushes the remaining catalyst 24 with a blade 33 provided in front. The blade 33 can be moved up and down by an actuator 37. The monitoring video imaged by the video camera 35 is transmitted outside the reaction furnace 2 and displayed on the display unit 8. The monitoring video may be displayed on a display different from the display unit 8.

  The light emitting unit 4 has three point light sources 41 arranged two-dimensionally or three-dimensionally, and functions as a marker for detecting the position and posture of the moving body 3. Each of the point light sources 41 has different spectral distributions and emits light in a wavelength region different from the wavelength of the light emitted from the distance measuring sensor 6. In the present embodiment, the point light sources 41 are arranged at the front center, the left rear, and the right rear on the main body 31, and are a red light emitting diode, a green light emitting diode, and a blue light emitting diode, respectively. Each point light source 41 is identified by the color of light emission. The arrangement of the point light source 41 and the color of light emission are not limited to this.

  The stereo camera 5 has a pair of video cameras (see FIG. 2). This video camera is sensitive to the light emitted from the point light source 41 and has little sensitivity to the light emitted from the distance measuring sensor 6. The stereo camera 5 may be provided with an infrared cut filter that blocks light in the wavelength region emitted from the distance measuring sensor 6. The pair of video cameras in the stereo camera 5 have the same specifications such as the focal length, the shape and size of the imaging surface, the number of pixels, and the like, and are arranged substantially in parallel. Parallel equiposition is a camera arrangement in which the optical axes of a pair of video cameras are parallel and the imaging surfaces are arranged on the same plane, and the horizontal axes of the imaging surfaces are matched. In this embodiment, the optical axis of each video camera is substantially vertically downward. A stereo image captured by the stereo camera 5 is input to the processing unit 7 as a digital signal.

  The distance measuring sensor 6 emits light, measures the time of flight (TOF) of light that is reflected by the object and returns to the distance measuring sensor 6, and outputs the distance to the object as a distance image. This sensor is sometimes called a TOF camera (see, for example, US Pat. No. 2011/0025843). The distance measuring sensor 6 is provided at a position where the entire moving surface 21 in the reaction furnace 2 can be measured (see FIG. 2). The light emitted from the distance measuring sensor 6 is infrared light and has a wavelength range different from that of visible light emitted from the point light source 41.

  The stereo camera 5 and the distance measuring sensor 6 are attached to the frame 51. The frame 51 is suspended from the in-furnace floor surface 22 at a certain height by a chain 52 or the like. With this configuration, in this embodiment, the stereo camera 5 and the distance measuring sensor 6 are provided at a height of about 2 m from the furnace floor 22.

  The processing unit 7 includes a memory that stores an image processing program and the like, and a CPU that executes the image processing program and the like. In order to increase the processing speed in the processing unit 7, hardware for image processing such as an FPGA (Field Programmable Logic Gate Array) may be added. When the optical axis of the video camera in the stereo camera 5 is not physically parallel, the processing unit 7 corrects the stereo image by image processing so that the stereo image becomes an image of parallel equivalence. Further, the processing unit 7 corrects distortion of the angle of view caused by the lens of the stereo camera 5. In order to perform these corrections, a simple pattern with a strong contrast such as a checkered pattern is captured in advance, and is stored in the processing unit 7 as correction data. The processing unit 7 calculates the spatial position of the point light source 41 based on the corrected stereo image, the optical axis interval and the focal length of the stereo camera. The processing unit 7 detects the position of the moving body 3 by calculating the spatial position of at least one point light source 41 of the light emitting unit 4, and calculates the spatial position of each of the three point light sources 41. The posture of the moving body 3 is detected. Further, the processing unit 7 processes the distance image output from the distance measuring sensor 6, recognizes the wall surface of the reaction furnace 2 and removes unnecessary objects such as cables, and detects the shape of the moving surface 21. The processing unit 7 has map data in the reactor 2 and refers to the map data in image processing.

  Here, the principle by which the processing unit 7 calculates the spatial position will be described with reference to FIG. 4 (Keiji Miyoshi, “Basics of Stereoscopic Image Recognition by Stereo Method and Application to In-Vehicle Camera”, published by Triqueps Co., Ltd., 2007, reference). The right optical axis AR of the right video camera (hereinafter referred to as the right camera) and the left optical axis AL of the left video camera (hereinafter referred to as the left camera) are parallel. The right imaging surface SR by the right camera and the left imaging surface SL by the left camera are located on the same plane. Let (X, Y, Z) be the actual space coordinate system with the focal point FR of the right camera as the origin. A coordinate system having the origin at the intersection with the right optical axis AR on the right imaging surface SR is defined as (xR, yR). A coordinate system having an origin at the intersection with the left optical axis AL on the left imaging surface SL is defined as (xL, yL). The X, xR, and xL axes are directions from the left camera focal point FL to the right camera focal point FR. yL = yR. The projection point of the actual space point P (X, Y, Z) on the right imaging surface SR is mR (xR, yR), and the projection point on the left imaging surface SL is mL (xL, yL). The parallax is (xL-xR). The focal length is f, and the optical axis interval of the stereo camera is B. At this time, Z = B · f / (xL−xR), X = Z · xR / f, and Y = Z · yR / f, and the spatial position (X, Y, Z) of the point P is calculated.

  The display unit 8 is a visual display device such as a liquid crystal display, and is connected to the processing unit 7. The processing unit 7 aligns and superimposes the image representing the posture of the moving body 3 and the image representing the shape of the moving surface 21 on the display unit 8.

  In addition to the above configuration, the detection system 1 includes an operation unit 9 that remotely controls the movement of the moving body 3. The operation unit 9 includes an input device such as a keyboard and a mouse that accepts an operation input, a CPU that generates a control signal for controlling the movement of the moving body 3 in accordance with the operation input, and is near the display unit 8. Installed. The CPU of the processing unit 7 may also be used as the CPU of the operation unit 9. The operation unit 9 is connected to the moving body 3 by a cable 91. The control signal generated by the operation unit 9 is output to the moving body 3 via the cable 91. The cable 91 also functions as a cable body that suspends the moving body 3 when the moving body 3 is put into the reaction furnace. Operating energy may be supplied to the moving body 3 via the cable 91.

  The moving body 3 may be configured to autonomously move based on the shape of the moving surface 21 measured by the distance measuring sensor 6 and the position and orientation of the moving body 3 detected by the processing unit 7. Such a moving body 3 is an autonomous mobile robot, and includes a storage unit in which map data in the reactor 2 is stored in advance, and autonomously travels on the moving surface 21 with reference to the map data.

  In the detection system 1 configured as described above, the moving body 3 is placed in the reaction furnace 2 after the reaction furnace 2 is filled with nitrogen. The position and orientation of the moving body 3 and the shape of the moving surface 21 detected by the distance measuring sensor 6 are displayed on the display unit 8. In the case of remotely controlling the movement of the moving body 3, the worker operates the operation unit 9 while looking at the display on the display unit 8 in an office or the like outside the reaction furnace 2. When the moving body 3 is autonomously moved, information on the position and posture of the moving body 3 and the shape of the moving surface 21 detected by the processing unit 7 is transmitted to the moving body 3 via the cable 91. Based on such information, the mobile body moves autonomously with reference to map data. The moving body 3 moves while breaking the slope of the remaining catalyst 24 with the blade 33, and discharges the remaining catalyst 24 from the hole 23. The discharge of the residual catalyst 24 is confirmed by the shape of the moving surface 21 displayed on the display unit 8.

  According to the detection system 1 according to the present embodiment, since the stereo camera 5 captures a stereo image of the light emitting unit 4 that emits light, a stereo image can be captured even in an environment with low illuminance in the reactor 2, and the stereo image Based on this, the position and orientation of the moving body 3 can be detected. Since the distance measuring sensor 6 measures the distance of the moving surface based on the time of flight of light, the shape of the moving surface 21 can be detected even if the contrast of the moving surface 21 is low. Further, since the position and orientation of the moving body 3 and the shape of the moving surface 21 are displayed on the display unit 8, the position and orientation of the moving body 3 with respect to the shape of the moving surface 21 can be grasped, and the movement of the moving body 3 can be understood. Control becomes easy.

  Since each of the point light sources 41 emits light having different spectral distributions (lights having different colors), each point light source 41 can be identified and the position of each point light source 41 is detected. Thus, the posture of the moving body 3 can be detected. Further, since the point light source 41 emits light (visible light) in a wavelength range different from the wavelength of light (infrared rays) emitted from the distance measuring sensor, the operations of the distance measuring sensor 6 and the stereo camera 5 do not interfere with each other. .

  Since the movement of the moving body 3 is remotely operated, the moving body 3 can be operated away from a harsh environment, and the worker is released from the harsh work.

  When the mobile body 3 is moved autonomously, work is saved.

  In addition, this invention is not restricted to the structure of said embodiment, A various deformation | transformation is possible in the range which does not change the summary of invention. For example, the target for which the detection system 1 is used is not limited to the reaction furnace 2. The moving body 3 can be used for various operations by attaching a robot arm, a tool or the like instead of the blade 33. The number of point light sources 41 of the light emitting unit 4 may be four or more. Thereby, even if light emitted from some of the point light sources 41 is blocked by a catalyst or the like, the probability that the light emitted from the three point light sources 41 is captured by the stereo camera 5 is increased, and the posture of the moving body 3 is detected. The probability of doing will increase.

DESCRIPTION OF SYMBOLS 1 Mobile body and moving surface detection system 3 Mobile body 4 Light emission part 41 Point light source 5 Stereo camera 6 Distance sensor 7 Processing part 8 Display part 9 Operation part

Claims (4)

A moving body that moves on the moving surface;
A light emitting section having three or more point light sources arranged on the moving body;
A stereo camera and a distance measuring sensor provided at a position overlooking the moving body;
A processing unit for processing outputs of the stereo camera and the distance measuring sensor;
A display unit for displaying the output of the processing unit,
The stereo camera captures a stereo image of the light emitting unit,
The distance measuring sensor emits light to the moving surface, measures the distance of the moving surface based on the flight time of the light reflected and returned by the moving surface,
The processing unit detects the position and orientation of the moving body based on a stereo image captured by the stereo camera, detects the shape of the moving surface based on the output of the distance measuring sensor, and detects the position and orientation of the moving body. And a moving surface detection system for displaying the shape of the moving surface on the display unit.   2. The moving body and the moving surface according to claim 1, wherein each of the point light sources emits light having a wavelength range different from a wavelength of light emitted from the distance measuring sensor while having different spectral distributions. Detection system.   The moving body and moving surface detection system according to claim 1, further comprising an operation unit that remotely controls movement of the moving body. The moving body and moving surface detection system according to claim 1, wherein the moving body moves autonomously based on the position and posture of the moving body detected by the processing unit and the shape of the moving surface. .

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