KR101030166B1 - Safety system for crane - Google Patents

Abstract

According to the present invention, in the situation where the crane driver cannot see the work site due to various obstacles present in the work site, the crane driver is safe and secured by automatically tracking the cargo being carried by the crane and the work site below. The present invention relates to a crane safety device that easily operates a crane and prevents a safety accident by transmitting a danger warning sound only to an operator working under the cargo and not all workers at the work site.

The crane safety device of the present invention includes a plurality of video cameras installed on an arm of a crane and a plurality of video monitors provided on an adjustment device (cab or remote controller) of the crane to display images captured by the video camera. It is configured to, but automatically adjusts the shooting direction vertical angle, the zoom magnification and the focus of the video camera according to the equations according to the crane operating state information. In addition, while the ultrasonic sending means for reproducing the audible band sound only in a specific area is installed on the arm of the crane, the vertical angle in the ultrasonic sending direction is automatically adjusted by a predetermined equation according to the crane operating state information.

Crane, crane, safety, outlook, warning sound, crane, safety, view field, warning sound

Description

Safety system for crane

The present invention relates to a safety device of a crane. More specifically, in the situation where the crane operator cannot see the work site due to various obstacles present in the work site, the crane driver is safe and secured by automatically tracking the cargo being carried and the work site below. The present invention relates to an apparatus for easily operating a crane and preventing a safety accident by giving a warning by audible means only to a worker working under the cargo, not all workers at the work site.

First, some terms used in the present specification are defined as follows to clarify meaning transfer. ' Elevation angle ' refers to an angle formed by a straight line with a horizontal plane, ' vertical angle ' means an angle formed by a straight line with a vertical line, and ' rotation angle ' means an angle formed by two straight lines on a horizontal plane.

Cranes are used to load and unload cargo in the transportation industry, transport and installation of construction materials in the construction industry, and assemble heavy equipment in the manufacturing industry. Therefore, although there are various forms according to its use, as shown in FIG. 1, an upper pulley 12 is provided at the end of a long and inclined arm 10 installed on a crane body (not shown), which is normally mounted by a driver. The lower pulley 21 is connected to the lower side of the rope 20 of several strands extending vertically from the pulley, and the lower pulley is provided with a hook, a string or a basket, and has a structure in which the cargo 30 is loaded and carried.

On the other hand, the crane's role is essentially to lift and move the heavy cargo 30 from its starting point 42 to its target point 41. However, the driver's field of vision is often obstructed by various obstacles in the workplace 40. One way to solve this problem is to operate a crane using a wired or wireless remote control. However, since the position at which the driver can simultaneously secure the field of view of the starting point and the target point is extremely limited, it can be secured only in either case. Even if visibility is secured, it does not look down on the job site from above, so it is not known whether the cargo has reached the target point 41 on the floor plan until the cargo suspended at high altitude is brought down to the job site height. Accordingly, the driver 51 operates the crane depending on the hand signal or the wireless communication signal of the workers 52, 53, 54, etc. located at the work site. This is not only very inconvenient to operate the crane, but also has a problem in that the efficiency of cargo transportation is also reduced.

In addition, the signals do not match with each other often cause a safety accident. In other words, there is always a possibility that a cargo carried by a crane collides with an obstacle at the work site, or a part of the cargo falls, resulting in human injury, that is, a safety accident. In order to prepare for such a safety accident, all workers performing various tasks at the workplace must pay attention to check the movement trajectory and current position of cargo directly with their own eyes. However, safety accidents do not occur frequently, and as time passes, there is a widespread safety insufficiency among workers, which neglects the above cautions, which can result in large-scale safety accidents leading to casualties. On the other hand, all the workers sincerely paying attention to the problem that all the work is temporarily suspended, there is a problem that the work efficiency of the worker is lowered.
On the other hand, as another means to solve this problem, a technique for monitoring the cargo below, the work site and the surrounding by installing a video camera on the upper pulley or lower pulley is used. However, this has a problem in that the crane driver manually adjusts the shooting direction, focus and zoom ratio of the video camera. Also, the work site directly below the bulky cargo is hidden by the cargo and is still invisible.

An object of the present invention to solve the above problems is to provide a means to automatically track the cargo being carried by the crane according to the operating state of the crane arm and the rope length and the work site below it to secure the field of view. It is also to provide a means of warning by audible means only to the worker working at the bottom of the cargo, not all workers at the work site.

Crane safety device of the present invention for solving the above problems is provided in a plurality of video cameras installed on the arm of the crane and the control device (cab or remote control) of the crane to display the image taken by the video camera It comprises a plurality of video monitors, but automatically adjusts the shooting direction vertical angle, the zoom magnification and the focus of the video camera according to the equations according to the crane operating state information.

In addition, while the ultrasonic sending means for reproducing the audible band sound only in a specific area is installed on the arm of the crane, the vertical angle in the ultrasonic sending direction is automatically adjusted by a predetermined equation according to the crane operating state information.

By means of the above-mentioned problem solving means, even if the elevation angle and the rotation angle of the crane arm and the length of the rope are changed according to the crane operating state, some of the video cameras automatically carry the cargo in transport and the rest of the work site below the cargo automatically. By tracking, the operator can always see the obstacles around the cargo and the work site situation below the cargo to ensure safe and easy operation.

In addition, since the driver can see the work site in the vertical direction below the cargo, it is possible to accurately find the target point without depending on the hand signal or wireless communication signal from the operator or lowering the cargo suspended at high altitude to the work site height.

On the other hand, only the worker working in the dangerous area under the cargo to listen to the warning and prepare for safety accidents, the rest of the site workers can safely focus on their work without paying special attention.

Hereinafter, with reference to the accompanying drawings, preferred embodiments provided to help understanding of the present invention will be described in detail. The following examples are provided for easier understanding of the present invention, and the scope of the present invention is not limited to these examples. In addition, in the description of the present specification and the accompanying drawings, it is to be noted that the components having the same purpose and function are kept consistent by having the same names and reference numerals as much as possible even if their configurations and drawings are different.

1 is a schematic view of a crane structure for explaining the operation principle of the safety device of the present invention in a crane having an inclined arm, in which only one video camera 11 is shown, as this tracks the cargo 30 and the target point 41 at the same time. Although illustrated, this is merely to show both cases in a single drawing in order to facilitate understanding of the technical idea of the present invention. In practice, it is more desirable to secure multiple views from different angles by installing multiple video cameras at various positions on the arm 10 and using each separately for the shop floor tracking and cargo tracking methods.

[Site tracking method]

First, the means by which the line of sight (shooting direction) of the video camera always tracks the working site vertically below the cargo, even if the crane arm has any elevation angle and rotation angle, will be described. In Figure 1 it can be seen that the following equation (1) is established. At this time, when the altitude of the work site is lower than the crane body (for example, underground), the h value becomes negative.

.................................(1)

.................................(One)

,

이므로 (1)식은 (2)식으로 표현된다.here

,

(1) is represented by (2).

.............................(2)

.............................(2)

If this expression is shown with respect to the vertical angle (phi) ₁ , it will become (3).

.........................(3)

......................... (3)

Therefore, if the vertical angle φ ₁ in the shooting direction of the video camera is adjusted according to the equation (3), no matter what the elevation angle θ of the crane arm has, the gaze of the video camera always keeps the work site below the vertical direction of the cargo being carried. To be tracked. Here, the elevation angle θ of the arm can be measured in real time, the height of the lower end of the crane arm y ₀ , the distance from the lower end of the crane arm to the video camera installation position l ₁ , the distance from the video camera installation position on the crane arm to the upper pulley installation position l ₂ can be predetermined or measured in real time.

On the other hand, the altitude h of the workplace can be estimated using, for example, the number of floors multiplied by 3m, or the value actually measured. However, this has an inaccurate or cumbersome disadvantage, so solving Eq. (2) with respect to the altitude h of the shop floor to find an improved solution gives Eq.

.........................(4)

.........................(4)

Here, if the value of φ ₁ is known, the values of the remaining variables are known values, so the value of h can be obtained by calculation. Therefore, it is possible to calculate by measuring the value of φ ₁ when carrying the first load or before starting the load transfer operation by the following illustrated procedure.

1) At any site location, lower the crane's lower hook (or the original cargo) to the floor of the site. This is to form a vertical line from the end of the arm to know the point where the vertical line meets the work site.

2) The driver operates the video camera's gaze adjusting means (button, joystick, etc.) so that the lower hook (or first load) is displayed at the center of the monitor. This is to allow the eyes of the video camera to go to the point where the vertical line meets the work site. The controller of the video camera knows the value of the vertical angle φ ₁ at this time.

3) When the driver presses the 'Working Altitude Calculation' button, the controller of the video camera calculates the value of h by substituting the value of φ ₁ into (4).

In the subsequent crane operation process, the controller of the video camera adjusts the vertical angle of the video camera according to Equation (3) using the h value obtained in the above process. On the other hand, when the altitude of the starting site and destination is different from each other and the h value applied in Eq. (3) is different, it is preferable to calculate and store both altitude values by the above process. At this time, what h value to use according to the crane operating situation is automatically selected by the video camera control unit according to the rotation angle and elevation angle of the crane arm, or the driver can directly select it.

[Automatic Cargo Tracking]

Next, we will describe the means by which the line of sight of a video camera always tracks a cargo, no matter how the length w of rope changes. In Figure 1 it can be seen that the following equation (5) is established. If the altitude of the cargo is higher than y ₁ , the denominator is negative and the value of φ ₂ is the second quadrant value.

.............................(5)

............. (5)

,

이므로 (5)식은 (6)식으로 표현된다.here

,

(5) is represented by (6).

(6)

If this expression is _shown with respect to the vertical angle (phi) ₂ , it will become (7).

............................(7)

(7)

이므로 (8)식으로 나타낼 수 있으며, 이 식에 의해 연산한 값을 운전자에게 크레인 운전정보로 제공할 수 있다.Therefore, if the vertical angle φ ₂ in the shooting direction of the video camera is adjusted according to (7), the video camera's line of sight always tracks the cargo no matter what the length of the rope, i.e. the distance w from the upper pulley to the cargo. . Here, the elevation angle θ of the arm can be measured in real time, and the distance l ₂ from the video camera installation position on the crane arm to the upper pulley installation position can be predetermined or measured in real time. On the other hand, the altitude z from the shop floor to the cargo

Therefore, it can be expressed by Equation (8), and the value calculated by this equation can be provided to the driver as crane operation information.

.........................(8)

.........................(8)

[Focus automatic adjustment means]

Conventional focus auto-adjusting means of the camera measures the distance to the subject using ultrasonic waves or infrared rays, and then detects the phase of the image formed by the optical device and an active method of adjusting the optical device based thereon. The contrast of the image is roughly measured by a manual method of adjusting the optical device. However, all of these methods require complex electronics, which increases production costs.

,

를 d에 대해 풀면 (9)식이 되어서 능동방식의 초점 자동조절 수단의 구현에 사용될 수 있다.In the present invention, the distance to the subject can be obtained by a simple calculation. Distance from camera to subject d (d ₁ And to find d ₂ )

,

Solving for d can be used in the implementation of an active focus auto-adjustment means (9).

......................................(9)

(9)

[Zoom magnification automatic adjustment means]

On the other hand, the distance from the video camera to the subject changes according to the driving state of the crane. If the distance increases, the size of the subject displayed on the monitor becomes smaller so that the driver cannot see the details. Although it may be used as it is to maintain the sense of the distance according to the crane operating state, the size of the subject displayed on the monitor for easier crane operation, it is preferable that the size is always constant to the driver. For this purpose, a zoom magnification adjustment means is necessary.

The image of the subject S ₀ at any distance d _0, adjusted to the size of the driver is desired on the monitor screen (zoom setting) Assuming that the zoom ratio Z ₀ at the time when, the image displayed on the monitor screen and the distance d ₀ S _img0 is represented by the formulas (10) and (11), respectively. Where k is a proportional constant.

....................................(10)

(10)

....................................(11)

(11)

On the other hand, the image in which the subject S ₀ at the distance d is displayed on the monitor screen is represented by the expression (12).

......................................(12)

(12)

Here, if the two images S _img0 and S _img displayed on the monitor screen are the same regardless of the distance, the condition of equation (13) must be satisfied.

..................................(13)

....................... (13)

Substituting equations (9) and (10) into this equation and solving for Z yields equation (14).

................................(14)

(14)

라고 정의하면, C는 운전자의 초기설정에 의해 정해지는 비례상수이며, 줌 배율 Z의 값은 다음의 (15)식으로 주어진다.here,

Is a proportional constant determined by the driver's initial setting, and the value of the zoom factor Z is given by the following expression (15).

.......................................(15)

....................... (15)

If the video camera controller automatically adjusts the zoom factor Z of the video camera by this equation, no matter what angle the elevation angle θ of the crane arm and the vertical angle angle φ of the video camera have, regardless of the distance to the subject, The image size of the displayed subject is always constant. In addition, since the value of the proportionality constant C is changed even if the driver arbitrarily changes the size of the subject displayed on the screen while the crane is operating, the image of the subject displayed on the monitor afterwards maintains the changed size.

[Expansion Generality of Formula]

On the other hand, in the industrial field, as shown in FIG. 2, not the inclined arm is also used a lot of cranes, such as a ceiling crane, gantry crane (gantry crane), tower crane (tower crane) and the like. This type of crane is characterized in that the upper pulley 12 is not fixed to one end of the arm, but is movable side to side along the rail provided in the arm 10, and the arm is movable on a horizontal plane at altitude y ₀ .

In the overhead crane, the arm 10 moves along the rails provided on both walls 15 and 16, and in the gantry crane, the arm 10 is fixed to the upper ends of the piers 15 and 16, and the whole moves along the rails installed on the ground. The arm is movable in a direction perpendicular to. In the tower crane, an arm 10 is installed at an upper end of the tower 15 (no 16), and the arm is movable on a horizontal plane having a height y ₀ by operating the tower in a rotation angle range of 360 °.

인 경우에도

이 되어 전술한 수식들이 무리 없이 적용가능하다. 또 비디오 카메라 11이 암 10에 고정되지 않고 상부 도르래 12에 고정되어 상부 도르래와 함께 움직이는 경우에도 전술한 수식들은 무리 없이 적용가능하다. 이 경우에 l₂ 값이 고정되고 l₁ 값이 변하게 된다.The above equations also apply when the arm of the crane is level, ie when the elevation angle θ of the arm is 0 °. At this time, the value of l ₁ is fixed and the value of l ₂ is changed, and cosθ = 1 and sinθ = 0 in the above-described equations. In addition

Even if

Thus, the above-described formulas can be applied without difficulty. In addition, even when the video camera 11 is not fixed to the arm 10 but fixed to the upper pulley 12 and moves together with the upper pulley, the above-described equations can be applied without difficulty. In this case, the value of l ₂ is fixed and the value of l ₁ is changed.

On the other hand, there are cases where two or more arms are connected by joints according to the use of the crane, and the above-described formulas also apply. 3 is of length l ₃ of the bottom arm length l ₄ of the upper arm to a display case is connected by a joint. As shown in (a) of FIG. 3, when the upper arm is provided with the video camera 11, since the elevation angle of the lower arm is θ ₃ , the value of y ₀ can be obtained by the following equation (16).

......................................(16)

(16)

As shown in the figure, the hypothetical length l _{1V, which} is the sum of the length l _E and l ₁ with the upper arm extending to the ground, is given by Eq. (17), which can be used instead of l ₁ in the above equations. have. At this time, the value of y ₀ is 0.

...............................(17)

(17)

In addition, as shown in (b) of FIG. 3, when the lower arm is provided with the video camera 11, an imaginary length l _{2V, which} is the sum of the length L _E and l ₂ with the lower arm extended, is given by the expression (18), This can be used instead of l ₂ in the above equations.

...............................(18)

......................................... (18)

The imaginary rope length w _{V, which} is the sum of the elongated rope lengths w _E and w is given by Eq. (19), which can be used instead of w in the above equations.

.....................(19)

.......... (19)

[Worker safety alarm]

Typically, both the eyes and ears of a worker are used for the work he performs, but the eyes are used more heavily than the ears. Unlike the eye, the ear also has the ability to detect multiple signals at the same time, ie multitasking. Therefore, it is advisable to use an audible measure to alert the worker. It is also desirable from the point of view of work efficiency to give a hazard warning only to the operator working in a hazardous area under the cargo being carried by the crane, not to all workers at the work site. Therefore, a sound generating means (loudspeaker) having very high directivity is required to give a warning signal only to a worker working in the dangerous area. However, the audio frequency band loudspeakers of the prior art are not suitable for this purpose because of their low directivity.

One embodiment of the safety warning means of the present invention uses a well-known beat (beat) phenomenon, as shown in Figure 4 two ultrasonic beams having a similar frequency from the two ultrasonic beam transmitters 13, 14 are the dangerous area 45 In order to meet at, the difference frequency component of the synthesized signal is heard in the operator's ear in the danger zone. At this time, the vertical angle of each ultrasonic beam transmission direction should be adjusted by the above-described automatic operation site tracking means, that is, Equation (3) to automatically track the dangerous area no matter what elevation angle the crane arm has.

Figure 4 (b) shows an unusual case in which any one of the two ultrasonic beam transmitters 14 is installed in the upper pulley position. Since the beam delivery direction of this 14 is l ₂ in (3) and phi ₁ is always 0, that is, it is always a direction perpendicular to the plane, substantially no vertical angle adjustment is necessary. This unusual case also applies to the adjustment of the vertical angle in the shooting direction of the video camera described above.

On the other hand, when two acoustic signals having similar frequencies are synthesized, the synthesized signal is expressed by the following equation (20). 5 shows the waveform of the synthesized signal graphically. As shown in FIG. 5, the synthesized signal includes an envelope of a difference frequency component in which a carrier of a sum frequency component having a frequency of (f ₁ + f ₂ ) / 2 has a frequency of (f ₁ −f ₂ ) / 2. Amplitude-modulated by At this time, when the two frequency components fall within the audible band, the tone sound of the sum frequency component is heard, but the human ear senses that the tone sound is periodically changed. This is called beat.

......(20)

...... (20)

In the present invention, the frequency of the ultrasonic band is used for the f ₁ and f ₂ frequencies, and the difference frequency component falls within the audible band, so that the tone sound of the difference frequency component is heard only by the operator in the danger zone 45. In this case, when the two ultrasonic beams are each a continuous single tone signal, the difference frequency signal may also become a continuous single tone signal in the form of 'beep', which may be annoying to the operator's ear. Therefore, it is more preferable for the operator to hear a warning sound in which one or two of the two ultrasonic beams repeat the ON-OFF at the same time.

On the other hand, relatively recent US-based companies such as Holonics (http://www.holosonics.com) and ATC (http://www.atcsd.com) have commercialized highly directional speakers. It forms a high-directional ultrasonic beam using a plurality of ultrasonic vibrators arranged in two dimensions, and when the ultrasonic signal modulated by the acoustic signal is sent in the form of the ultrasonic beam, the audible band due to the nonlinear motion characteristics of the air molecules As a technology capable of reproducing an acoustic signal, it is a high-directional speaker capable of transmitting sound only to a specific region or a specific person even if the transmission distance is long.

Another embodiment of the safety alarm means of the present invention is implemented by using the high-directional speaker, but by adjusting the sound transmission direction of the speaker by the above-mentioned automatic shop floor tracking means. In this case, only one high-directional speaker, not two, has a merit of transmitting not only a single tone sound but also a driver's voice message to the operator.

The above detailed description of the configuration of the present invention and the preferred embodiments thereof, the present invention is not limited to the above-described preferred embodiments, but various improvements, modifications, and replacements within the scope not departing from the gist of the present invention Or it can be easily understood by those skilled in the art that it can be carried out in addition. On the other hand, it is to be understood that the expression "comprises" or "comprising" is not intended to exclude the inclusion of components that are not directly related to the subject matter of the present invention.

1 is a schematic view of a crane structure for explaining the operation principle of the safety device of the present invention in a crane having an inclined arm.

Figure 2 is a schematic view of the crane structure for explaining the operation principle of the safety device of the present invention in a crane having a horizontal arm, such as a overhead crane, gantry crane, tower crane.

Figure 3 is a schematic view of the crane structure for explaining the operation principle of the safety device of the present invention when a plurality of arms are connected by a joint.

Figure 4 is a schematic view of the crane structure for explaining the sound generation principle using ultrasonic waves.

5 is a waveform diagram for explaining a beat phenomenon.

<Description of Major Codes in Drawings>

10 Crane Arms 11 Video Camera

12 upper pulley 13,14 ultrasonic beam transmitter

20 ropes 21 lower pulley

30 Freight 40 Work Site

45 Dangerous Areas

Claims (6)

A crane safety device comprising one or more video cameras installed on an arm of a crane and a video monitor provided on an adjustment device of the crane to display an image captured by the video camera. Crane safety device characterized by the vertical angle of the shooting direction by the formula.

Where φ is the vertical angle in the shooting direction of the video camera, θ is the elevation angle of the crane arm, y ₀ is the altitude of the lower part of the crane arm, h is the altitude of the work site, and l ₁ is the position from the bottom of the crane arm to the video camera installation position. Distance, l ₂ is the distance from the video camera installation position to the upper pulley installation position.) A crane safety device comprising one or more video cameras installed on the arm of a crane and a video monitor provided on an adjustment device of the crane to display an image taken by the video camera, wherein some of the video cameras are represented by the following equations. Crane safety device, characterized in that the vertical angle of the shooting direction is adjusted.

(Where φ is the vertical angle in the shooting direction of the video camera, θ is the elevation angle of the crane arm, w is the distance from the upper pulley to the cargo, l ₂ is the distance from the video camera installation position to the upper pulley installation position.) The crane safety device according to claim 1 or 2, wherein the video camera further comprises a zoom magnification automatic adjustment means according to the following equation.

(Where Z is the zoom factor of the video camera, C is the proportional constant, θ is the elevation angle of the crane arm, and Φ is the vertical angle in the shooting direction of the video camera.) The crane safety device according to claim 1 or 2, wherein the video camera further has an automatic focus control means based on distance information given by the following equation.

(Where d is the distance between the video camera and the subject, φ is the vertical angle in the video camera shooting direction, θ is the elevation angle of the crane arm, and l ₂ is the distance from the video camera installation position to the upper pulley installation position.) The crane safety device according to claim 1 or 2, wherein the crane safety device further comprises two or more directional ultrasonic beam emitters installed on the arms of the crane, each beam emitter being beam-transmitted by the equation of claim 1. Directional control of the vertical angle, at least one ultrasonic beam uses a different frequency than the remaining ultrasonic beam, the difference between the frequency is characterized in that the crane safety device. 3. The crane safety device according to claim 1 or 2, wherein the crane safety device further comprises a highly directional speaker made by a technique of reproducing an audible band sound signal using a plurality of ultrasonic vibrators arranged two-dimensionally, wherein the speaker is a crane. Installed on the arm of the crane safety device characterized in that for adjusting the vertical angle of the sound signal transmission direction by the equation of claim 1.

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