JP6342705B2 - Boom collision avoidance device for work equipment - Google Patents

Description

  The present invention relates to a boom collision avoidance device for a work machine that is used in a work machine having a work boom and that avoids a collision between the boom and the obstacle in order to prevent the boom from colliding with an obstacle during work.

  Some working machines having a working boom include a device that restricts the position and posture of the boom in order to prevent the boom from interfering with an obstacle during work. For example, the height limiting device described in Patent Document 1 geometrically positions the crane boom based on detection values such as a boom angle and a boom length in order to prevent the boom from interfering with an obstacle located above during operation. The control is performed so that the boom position does not exceed the designated work regulation range.

JP 2003-267666 A

  However, in the technique described in Patent Document 1, since the position of the boom of the crane is calculated geometrically, in order to set the work regulation range, for example, it is suspended between two power poles that become obstacles. Distance data from the obstacles such as the electric wire, such as how far the electric wire stands from the top of the crane boom, in which direction it is suspended, and how high it is (Environmental data) must be accurate.

Also, the height of the top of the boom changes each time depending on the extension of the crane outriggers. If the position information is not grasped, the relative position of the boom top of the crane with respect to the obstacle such as an electric wire cannot be grasped and the operation is not performed accurately. Therefore, there is a problem that it is difficult to set a complicated work regulation range. In addition, when the work environment data is an input error so-called “poca mistake” or the work environment data itself is incorrect information, the height limit setting value is set to a position higher than the obstacle, The boom may collide with an obstacle.
Here, the technique described in Patent Document 1 geometrically calculates the position of the boom with respect to the obstacle. However, in order to avoid the obstacle, as another measure that does not input the work environment data, It is also possible to use sound waves or laser scanning. For example, in the case of using ultrasonic waves, the distance from the time until the ultrasonic waves are transmitted and reflected and returned to the obstacle can be measured. Further, for example, in the case of laser scanning, the distance to the obstacle can be measured by irradiating the surroundings with a laser and how to shift the irradiation point.

However, when using an ultrasonic sensor, if the ultrasonic directivity is wide, pinpoint measurement cannot be performed and the detection accuracy becomes rough. On the other hand, if the ultrasonic directivity is narrow, a wide range is measured. Has the problem of requiring a large amount of sensors. In the case of laser scanning, if the obstacle is easy to absorb light, such as black, it becomes difficult to detect, and it is necessary to increase the laser intensity to perform measurement under sunlight irradiation conditions. Therefore, there is a problem that it is dangerous when there is a person in the vicinity.
Therefore, the present invention has been made in view of such problems, and it is not necessary to set an artificial work regulation range, and there is a person in the vicinity of a complex-shaped obstacle quickly and nearby. It is another object of the present invention to provide a boom collision avoidance device for work implements that can start work safely.

  In order to solve the above problems, a boom collision avoidance device for a working machine according to an aspect of the present invention is used in a working machine having a working boom, and prevents the boom from colliding with an obstacle during work. A boom collision avoidance device for work implements for avoiding a collision between the boom and the obstacle, wherein a video camera provided at a tip of the boom and an image captured by the video camera are subjected to image processing, and An image processing unit that calculates a separation distance between the boom and the obstacle based on the result of the image processing, and a collision between the boom and the obstacle is avoided based on the information about the separation distance output from the image processing unit. And a collision avoidance control unit that performs collision avoidance control.

  Here, in the boom collision avoidance device for a work machine according to an aspect of the present invention, the video camera is provided so as to photograph a column from a tip of the boom, and the image processing unit is the video camera. The column image taken at any time and a reference image are compared to determine the presence or absence of an obstacle based on the difference between the images, and when it is determined that there is an obstacle, the bottom surface of the boom and the obstacle And the collision avoidance control unit may collide the lower surface of the boom with the obstacle based on the generated information on the separation distance. In some cases, it is preferable to perform an alarm to the operator or collision avoidance control that regulates the deceleration, stop or operation direction of the boom.

  Further, in the boom collision avoidance device for work implements according to an aspect of the present invention, the video camera is provided only in one unit so as to photograph the column from the tip of the boom, and the posture of the video camera is It is preferable that the optical axis is set so that its own optical axis is substantially parallel to the extending direction of the lower surface of the boom, and the point where the extended line of the optical axis intersects the upper part of the column is set as the boom base point.

  Furthermore, in the boom collision avoidance device for a work machine according to one aspect of the present invention, the image processing unit processes the entire image including the boom base point and the uppermost part of the obstacle in a bitmap format. Based on the obtained pixels, the whole image is recognized as a grid point divided into a grid, and the number of grid points in the vertical direction of the pixel between the top of the obstacle and the boom base point in the whole image is calculated. And it is preferable to acquire the calculated number of grid points as the information on the separation distance.

  According to the boom collision avoidance device for a work machine according to an aspect of the present invention, the configuration includes a video camera and an image processing unit, and performs collision avoidance control based on image processing. Whether or not there is a possibility of collision can be determined based on the image information. Since the video camera and the image processing unit function as a proximity sensor, it is possible to eliminate human error such as a mistake in setting the work regulation range. In addition, since there is no need for prior settings for inputting work environment data, the work can be started quickly and safely.

  Further, since the collision determination is based on image processing, image information can be acquired even if the obstacle has a complicated shape, and even a small obstacle can be detected. In addition, since the apparatus can be configured from images acquired by a single video camera, the number of sensor placement locations (number of placements) is small, so manufacturing is easy and local remodeling is also easy. In addition, since the video camera can shoot only with ambient light, it is safer than the case of laser scanning.

  Moreover, since it is easy to recognize an obstacle other than glass or a mirror surface, it can be applied with high versatility to the situation at the work site. For example, as a situation of a work site where the boom collision avoidance device for a work machine according to the present invention can be used, if the work machine is a crane, when carrying out a lifting work near an electric wire or a power pole in an urban area or a railroad track, etc. In addition, contact between the lower surface of the boom and the electric wire can be prevented. Further, for example, when carrying out a hanging work at a construction site, it is possible to carry in a load while avoiding contact between the bottom surface of the boom and a scaffold or the like.

It is a typical perspective view explaining the vehicle-mounted crane which is one Embodiment of the working machine carrying the boom collision avoidance device for working machines which concerns on 1 aspect of this invention. It is a flowchart of the collision avoidance process (main process) which a boom collision avoidance apparatus performs. It is a flowchart of the separation distance measurement process which a boom collision avoidance apparatus performs in the collision avoidance process. It is the typical explanatory view which looked at the crane body from the side. It is the typical explanatory view which looked at the column of the crane main part from the visual field direction of a video camera.

Hereinafter, a vehicle-mounted crane that is an embodiment of a work machine equipped with a boom collision avoidance device for a work machine according to an aspect of the present invention will be described with reference to the drawings as appropriate. In addition, this embodiment demonstrates the example which prevents a contact with a boom lower surface and an electric wire, when carrying out the hanging work with a vehicle-mounted crane in the vicinity of an electric wire or an electric pole in an urban area, a track, or the like.
As shown in FIG. 1, this vehicle-mounted crane (hereinafter, also simply referred to as “crane body”) 1 is mounted between a driver's seat 9 a and a loading platform 9 b of a vehicle 9 such as a truck, and the chassis of the vehicle 9. The base 2 is fixed on a frame (not shown). A pair of outriggers 8 that can project in the vehicle width direction are provided on the left and right sides of the base 2. A column 3 is erected on the base 2 at a position in the center of the vehicle width so as to be turnable. A boom 4 is pivotally supported at the upper end of the column 3 so as to be able to expand and contract. The column 3 is provided with a winch (not shown), and the wire rope 5 from the winch is hung on the hook 6 of the tip 4t of the boom 4.

The crane 1 is provided with a plurality of actuators (not shown) corresponding to the boom 4 undulation, expansion / contraction, turning, and driving of the winch. The plurality of actuators are provided in the vicinity of the base 2 and are driven by the control of the controller 30 that controls the boom operation, so that the boom operation including undulation, expansion and contraction, and turning operation is possible.
When crane operation is performed, when an operator inputs a desired crane operation from a position away from the crane body 1 by operating each selection switch and speed lever of a remote controller (not shown), a signal corresponding to the desired crane operation is obtained. Is input to the controller 30 by wireless communication, and the controller 30 outputs an operation command for operating each actuator of the crane body 1 to start the operation of a desired actuator.

Here, in the crane body 1, one video camera 10 and an image processing device 20 are attached to the tip 4 t of the boom 4. The controller 30 has a function as a collision avoidance control unit, and is configured to be able to execute a collision avoidance process based on information about a separation distance (described later) output from the image processing device 20 that is an image processing unit. Has been.
Specifically, as shown in FIG. 1, the video camera 10 is provided on the lower side of the boom tip 4t so that the column 3 of the crane body 1 can be photographed. In the example of the present embodiment, the video camera 10 is mounted such that the posture of the video camera 10 is substantially parallel to the extending direction of the lower surface of the boom 4. A point where the extension line of the optical axis intersects with the upper part of the column 3 of the crane body 1 is set as a boom base point (see FIG. 4).

  When the image processing device 20 captures an image captured by the video camera 10 and executes a program for measuring a separation distance, which will be described later, an object that shields the column 3 of the crane body 1 is captured by the video camera 10. In addition, the shielding object is recognized as an obstacle S. When the image processing device 20 detects the approach of the obstacle S to the lower surface of the boom 4, the image processing device 20 calculates the vertical distance between the obstacle S and the boom base point on the image as the separation distance T, and this separation distance. T information is sent to the controller 30. In the example of the present embodiment, the work is performed between the two power poles H that are erected apart from each other, and the electric wire S stretched between the power poles H is an obstacle. is there.

  And the controller 30 as a collision avoidance control part executes the program of a collision avoidance process, and the separation distance T between the boom base point and the obstacle S falls within a predetermined threshold C (see FIGS. 4 and 5). On the other hand, the boom 4 exceeds a predetermined facing position with respect to the threshold C line (in the example of the present embodiment, the line including the optical axis of the video camera 10 (see FIG. 4)) when it becomes less than the predetermined value. When the obstacle S approaches the lower surface of the vehicle), an alarm to the operator, or collision avoidance control such as deceleration, stop of the crane or restriction of the operation direction is performed.

Next, the collision avoidance process will be described in more detail.
When the collision avoidance process is executed by the collision avoidance control unit of the controller 30, as shown in FIG. 2, first, the process proceeds to step S1, and the alarm distance and stop distance set in advance with reference to the threshold C line. , And the reference image is read and initial setting is performed. Here, the reference image is an image when the column 3 of the crane body 1 is viewed from the direction of the visual field of the video camera 10 in a state where the obstacle S is not present in the visual field of the video camera 10 (the obstacle S in FIG. Excluded image).

  In the subsequent step S2, a series of “distance measurement processing” is executed in the image processing apparatus 20, and the vertical distance (number of pixels) between the boom 4 and the obstacle S is obtained as the separation distance T by the image processing (see FIG. 4), the process proceeds to step S3. Details of the “distance measurement process” will be described later. In step S3, obstacle determination is performed based on the information of the separation distance T. That is, if the obstacle determination result in step 2 is “no obstacle” (No), the process returns to step 2, and if the obstacle determination result is “obstacle” (Yes), the process proceeds to step 4 To do.

  In step S4, the separation distance T to the obstacle S measured in step 2 is compared with a preset warning distance, and it is determined whether or not the separation distance T is equal to or less than the warning distance. That is, if the separation distance T is equal to or less than the warning distance (separation distance ≦ alarm distance) (Yes), it is determined that the lower surface of the boom 4 is close to the obstacle S, and the process proceeds to step S5, otherwise (No). Then, it is determined that the lower surface of the boom 4 is sufficiently separated from the obstacle S, and the process returns to step S2. In step S5, since the boom 4 of the crane body 1 is close to the obstacle S, a signal for sounding an alarm is output and the process proceeds to step S6. As a result, an alarm such as a buzzer is sounded to alert the operator.

  In step S6, the separation distance T to the obstacle S measured in step 2 is compared with a preset stop distance, and it is determined whether or not the separation distance T is equal to or less than the stop distance. That is, if the separation distance is equal to or less than the stop distance (separation distance ≦ stop distance) (Yes), it is determined that the lower surface of the boom 4 is close to the obstacle S, and the process proceeds to step S7, otherwise (No), It is determined that the lower surface of the boom 4 is sufficiently away from the obstacle S, and the process returns to step S2. In step S7, since the boom 4 of the crane main body 1 is close to the obstacle S, in order to prevent the boom 4 of the crane main body 1 from contacting the obstacle S, the approach direction to the obstacle S (boom depression, contraction, The operation stop signal for the boom 4 to the left and right and on the hook is output, and the process returns to step S2.

Next, the separation distance measurement process during the collision avoidance process will be described in detail.
The separation distance measurement process in step S2 is executed in the image processing apparatus 20 in the example of the present embodiment. As shown in FIG. 3, first, the process proceeds to step S21, and the video camera provided at the boom tip 4t. The image of column 3 taken at 10 is acquired, and the process proceeds to step S22. In step S22, scale adjustment of the image of the video camera 10 is performed as pre-processing for image comparison. That is, the scale (zoom rate) and inclination of the image acquired from the video camera 10 are matched with the reference image. In subsequent step S23, as pre-processing for image comparison, a filtering process such as a smoothing process for noise removal and a flattening of a histogram is performed, and the process proceeds to step S24.

Here, an image with a biased histogram is an “image in which a portion not exposed to light is crushed in black” or “an image in which a portion that is strongly exposed to light is white”, but the histogram is flattened. As a result, the image of the portion that has been crushed in black or the portion that has been blown out in white becomes clear, and the obstacle can be detected more reliably.
In addition, noise occurs in images taken with a video camera due to various factors. When an image containing noise is processed as it is, it is possible to misrecognize the noise as an obstacle even though there is no obstacle in the shooting range. High nature. Although it is possible to separate obstacles and noise by image processing using information such as the size of the projected area of the object on the image, if a large amount of noise is determined by image processing, the time required for noise removal will be enormous . Therefore, before performing the obstacle determination, smoothing processing is performed in advance to remove noise.

In step S24, as a pre-process for image comparison, the image of the peripheral part of the column 3 is cut out, and the periphery of the column 3 necessary for the image comparison process and the background image not necessary for the image comparison process are separated. In subsequent steps S25 to S26, image comparison processing is performed. First, in step S25, the camera image captured by the video camera 10 cut out in step S24 is compared with a reference image using a processing method such as a difference method, and a difference between the two images is extracted.
In step S26, a comparison result between the reference image and the camera image taken by the video camera 10 is determined. Here, the reference image is stored in advance in the storage unit of the image processing apparatus 20, and when the obstacle S is recognized, foreign object detection by difference processing is used, and the reference image and a camera image taken by the video camera 10. And compare.

  That is, the difference between the pixel values is calculated by comparing the newly taken image of the column 3 of the crane body 1 with the stored reference image of the column 3 of the crane body 1. As a result, if there is no difference between the reference image and the camera image taken by the video camera 10 (if the pixel value difference is less than a predetermined value), it is determined that no obstacle is shown (No), and the process proceeds to step S27. To do. On the other hand, if the difference between the pixel values is equal to or larger than the predetermined value, it is determined that an object other than the column 3 is reflected so as to block the column 3 (Yes), and the process proceeds to step S29. For example, in the example shown in the vicinity of the symbol K in FIG. 5, the pixel is locally different because the obstacle S is reflected in black in the image portion of the column 3. That is, when the difference between the pixel values is equal to or greater than a predetermined value, it is determined that the obstacle S is captured.

In step S27, since the obstacle S is not shown, the obstacle determination result is set to “no obstacle”, and in the subsequent step S28, the current state of the column 3 of the crane body 1 is used as a reference image. Then, the camera image is overwritten on the reference image, and the process returns to the collision avoidance process which is the main process.
In step S29, since the obstacle S is shown, the obstacle determination result is set to "There is an obstacle", and in the subsequent step S30, the "separation distance calculation" is performed to calculate the separation distance T and the processing is performed. Return to the collision avoidance process. Here, the “separation distance calculation” sets the vertical distance (number of pixels) between the boom base point and the top of the obstacle S shown in FIGS. 4 and 5 to the separation distance between the bottom surface of the boom 4 and the obstacle S. Performs computation.

  That is, in the calculation process of the separation distance T, the entire image including the boom base point and the uppermost part of the obstacle handled on the image processing device 20 is processed in a bitmap format. Then, based on the pixels obtained by the processing, the whole image is recognized as grid points divided into grids. Next, the number of grid points in the vertical direction of the pixels between the top of the obstacle S and the boom base point in the entire image (the number of grids in the column) is calculated, and the calculated number of grid points is calculated as the separation distance. It is acquired as information. Thereby, the separation distance T between the lower surface of the boom and the top of the obstacle can be easily grasped.

Next, operation | movement of the collision avoidance apparatus of this vehicle-mounted crane 1 and its effect | action and effect are demonstrated.
When carrying out the crane work with the vehicle-mounted crane 1, the operator inputs a desired crane operation from the position away from the crane body 1 by operating each selection switch and speed lever of the remote controller. As a result, a signal corresponding to a desired crane operation is input to the controller 30 by wireless communication, and the controller 30 outputs an operation command for operating each actuator of the crane body 1 to operate the desired actuator. Thereby, at the time of crane work, the operator can perform boom operation including raising / lowering, extending / contracting, and turning operation of the boom 4 from a position away from the crane body 1.

Here, as shown in FIG. 1, when the work site is suspended in the vicinity of the electric wire S or the utility pole H in an urban area or a railway line, there is a concern about the contact between the lower surface of the boom 4 and the electric wire S. The
In contrast, the vehicle-mounted crane 1 of the present embodiment has a collision avoidance device that includes the video camera 10, the image processing device 20, and the controller 30, and this collision avoidance device is the above-described FIG. 3 is performed and collision avoidance control based on image processing is performed. Therefore, based on image information acquired in accordance with the situation of the work site, the boom 4 can be applied to the electric wire S that is an obstacle. The presence or absence of the possibility of collision of the lower surface can be determined.
According to the collision avoidance device, since the video camera 10 and the image processing device 20 are used to function as a proximity sensor, it is possible to eliminate human error such as a mistake in setting the work regulation range. In addition, since there is no need for prior settings for inputting work environment data, the work can be started quickly and safely.

  Moreover, according to this collision avoidance device, since the collision determination is based on the image information of the video camera 10, the image information can be acquired even if the obstacle S such as the electric wire has a complicated shape, and the fine obstacle such as the electric wire can be obtained. Even the object S can be detected. In addition, since the apparatus can be configured from images acquired by one video camera 10 as in the present embodiment, the number of sensor arrangement locations (number of arrangements) is small, so that the collision avoidance device can be easily manufactured and field modification can be performed. Easy to do. Further, since the video camera 10 can shoot only with ambient light, it is safer than the case of laser scanning. Moreover, according to this collision avoidance device, since it is easy to recognize if the obstacle S is other than glass or a mirror surface, it can be applied with high versatility to the situation at the work site.

In addition, the boom collision avoidance device for a working machine according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, an example in which the boom collision avoidance device for a work machine according to one aspect of the present invention is mounted on a vehicle-mounted crane is described. However, the present invention is not limited to this, and the work machine has a work boom. The present invention can be applied if there is any.

In the above embodiment, the example in which the image processing unit and the collision avoidance control unit are separately provided in the image processing device 20 and the controller 30 has been described. However, the present invention is not limited thereto, and for example, the image processing unit and the collision avoidance control are provided. Can also be provided in the controller 30.
Moreover, in the said embodiment, the example which prevents a contact with an electric wire when carrying out the hanging work near an electric wire or an electric pole in an urban area, a track, etc. as an example of the situation of the work site which can use the present invention. However, the present invention is not limited to this, and the present invention can be widely applied to uses for limiting the position and posture of the boom in order to prevent the boom from interfering with an obstacle during work. For example, the present invention can be applied to a purpose of carrying a load while avoiding contact with a scaffold or the like when performing a suspended load work at a construction site.

1 Vehicle-mounted crane (crane body)
2 base 3 column 4 boom 5 wire rope 6 hook 7 hoisting cylinder 8 outrigger 9 vehicle 10 video camera 20 image processing device (image processing unit)
30 controller (collision avoidance control unit)
H Telephone pole S Electric wire (obstacle)
T separation

Claims (4)

  A working machine boom collision avoidance device that is used in a working machine having a working boom and avoids a collision between the boom and the obstacle to prevent the boom from colliding with an obstacle during work,
  A video camera provided at the tip of the boom, a video taken with the video camera at any time and a reference image are compared to determine the presence or absence of an obstacle based on the difference between the images, and there is an obstacle The image processing unit that calculates the separation distance between the boom and the obstacle based on the result of the image processing at that time, and the information based on the separation distance output from the image processing unit. A boom collision avoidance device for work implements, comprising: a collision avoidance control unit that performs collision avoidance control for avoiding a collision between an boom and an obstacle. A working machine boom collision avoidance device that is used in a working machine having a working boom and avoids a collision between the boom and the obstacle to prevent the boom from colliding with an obstacle during work,
A video camera provided at the tip of the boom, an image processing unit that performs image processing on an image captured by the video camera, and calculates a separation distance between the boom and the obstacle based on a result of the image processing; A collision avoidance control unit for performing collision avoidance control for avoiding a collision between the boom and an obstacle based on the information on the separation distance output from the image processing unit ;
The video camera is provided to shoot a column from the tip of the boom,
The image processing unit compares the image of the column taken with the video camera at any time with a reference image to determine the presence or absence of an obstacle based on the difference between the images and to determine that there is an obstacle. The opposite distance between the lower surface of the boom and the top of the obstacle is generated as information on the separation distance,
The collision avoidance control unit, based on the generated separation distance information, alerts an operator or decelerates, stops or operates the boom when there is a risk of collision between the bottom surface of the boom and the obstacle. A boom collision avoidance device for a work machine, characterized in that a collision avoidance control for restricting the movement is performed .   The video camera is provided only in one so as to photograph the column from the tip of the boom, and the posture of the video camera is such that its optical axis is substantially parallel to the extending direction of the lower surface of the boom. The boom collision avoidance device for work implements according to claim 2, wherein a boom base point is set at a point where the extension line of the optical axis intersects with the upper part of the column.   The image processing unit processes the entire image including the boom base point and the uppermost part of the obstacle in a bitmap format, and grid points obtained by dividing the entire image into a grid based on the pixels obtained by the processing And the number of grid points in the vertical direction of the pixel between the top of the obstacle and the boom base point in the entire image is calculated, and the calculated number of grid points is acquired as the separation distance information The boom collision avoidance device for a work machine according to claim 3, wherein:

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