WO2009084819A1

WO2009084819A1 - System for predicting collision of cranes

Info

Publication number: WO2009084819A1
Application number: PCT/KR2008/007031
Authority: WO
Inventors: Hoon Oh; Jung Seok Heo; Jeong Il Choi; Sung Min Choi
Original assignee: University Of Ulsan Foundation For Industry Cooperration; Hyundai Heavy Industries Co., Ltd
Priority date: 2007-12-28
Filing date: 2008-11-28
Publication date: 2009-07-09
Also published as: KR100933992B1; KR20090072330A

Abstract

A method for predicting collision of cranes is disclosed. The method includes receiving GPS coordinates for the respective cranes from GPS receivers installed in a plurality of cranes, substituting the GPS coordinates of the respective cranes in three-dimensional (3D) models for the corresponding cranes pre-stored, and calculating coordinate information on a plurality of threshold points which are collision predicting reference previously designated to the 3D models based on the GPS coordinates, and obtaining a line segment connecting coordinates of a plurality of threshold points of cranes, and predicting collision of the respective cranes by using a minimum neighboring distance between the line segment obtained from the crane to be compared and the line segment obtained from a target crane.

Description

TITLE : SYSTEM FOR PREDICTING COLLISION OF CRANES

TECHNICAL FIELD

The present invention relates to a system for predicting collision of cranes, and more particularly, to a system for predicting collision of cranes, which can monitor in real time movement of diverse kinds of large-scale cranes working in a ship construction dock and, if collision between cranes is predicted, report danger of such collision. BACKGROUND ART At present, in a ship construction dock, various kinds of large-scale cranes for use in ship construction, such as Goliath cranes, jib cranes, tower cranes, and the like, perform their work as they move independently.

The Goliath crane moves along a Goliath rail. The jib crane performs upward/downward movement and left/right rotation and movement of a jib crane boom as it moves along respective jib rails. Also, the tower crane performs left/right rotation and movement of a tower crane boom as it is in its fixed position. The tower crane may remain in its fixed position for several or several tens of days, and may be moved to another position as needed.

Although the above-described cranes move slowly at speed of 0.6m/s at maximum and follow instructions of a ground operator, danger still exists in operating the cranes, e.g. collision may occur between cranes or crane booms due to a careless operator.

If collision occurs between the cranes, the cranes may be damaged to cause material loss, long-time interception of a ship construction process, and delay of goods delivery. In addition, the collision between the cranes may cause a loss of lives of crane operators or ground workers.

DISCLOSURE TECHNICAL PROBLEM

It is, therefore, an object of the present invention to provide a system for predicting collision of cranes, which can monitor movement of respective cranes in real time, predict collision between the cranes by using monitored values, and report danger of accident in real time.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. TECHNICAL SOLUTION

In accordance with an aspect of the present invention, there is provided a method for predicting collision of cranes, comprising the steps of: receiving GPS coordinates for the respective cranes from GPS receivers installed in a plurality of cranes; substituting the GPS coordinates of the respective cranes in three- dimensional (3D) models for the corresponding cranes pre-stored, and calculating coordinate information on a plurality of threshold points which are collision predicting reference previously designated to the 3D models based on the GPS coordinates; and obtaining a line segment connecting coordinates of a plurality of threshold points of the cranes, and predicting collision of the respective cranes by using a minimum neighboring distance between the line segment obtained from the crane to be compared and the line segment obtained from a target crane.

In the step of predicting the collision of the cranes, the collision of cranes is predicted by using the minimum neighboring distance between a line segment obtained from a crane in a reference region, in which the most recently moved crane is positioned, and a line segment obtained from a crane in a dangerous region which is an outside region of the reference region and is determined as it possibly collides with the crane in the reference region, among divided regions of a region in which crane work is performed.

The previously designated threshold point exists in a pair of threshold points comprising the first threshold point and the second threshold point of each crane, and the line segment is a line segment to connect the first threshold point with the second threshold point. In the step of predicting the collision of cranes, among test line segments connecting the first line segment obtained from the crane in the reference region and the second line segment obtained from a crane in the dangerous region, in case where inner products formed between vector of the first line segment and vector of the second line segment are all "0", and both end points of the shortest line segment are positioned on the first line segment and the second line segment, the shortest distance of the shortest line segment is determined as the minimum neighboring distance between the cranes.

In the step of predicting the collision of cranes, in case where inner products formed between vector of the first line segment and vector of the second line segment are all "0", and the shortest distance line segment, in which both end points are positioned on the first line segment and the second line segment, does not exist, the shortest distance of the shortest line segment, in which inner products formed between vector of the first line segment and vector of the second line segment are all "0" and both end points of the shortest line segment are positioned on the first line segment or the second line segment, the shortest distance of the shortest line segment is determined as the minimum neighboring distance between the cranes.

In the step of predicting the collision of cranes, in case where inner products formed between vector of the first line segment and vector of the second line segment are all "0", and the shortest distance line segment, in which any one of both end points are positioned on the first line segment or the second line segment, does not exist, the shortest distance of the shortest line segment, in which inner products formed between vector of the first line segment and vector of the second line segment are all "0" and both end points of the shortest line segment are positioned on the first line segment or the second line segment, the shortest distance of the shortest line segment is determined as the minimum neighboring distance between the cranes.

The crane comprises at least one of a Goliath crane, a jib crane and a tower crane. In the step of receiving the position of the crane, two GPS coordinates are transmitted from GPS receivers installed on both ends of a horizontal support block installed in a longitudinal direction of the crane, in case of the Goliath crane.

In the step of receiving the position of the crane, information on a rotation angle and tilt of a crane boom of the jib crane is received from a first rotation sensor and a tilt sensor installed on the crane boom of the jib crane, and information on a rotation angle of a crane boom of the tower crane is received from a second rotation sensor installed on a crane boom of the tower crane, as well as the GPS coordinates for the Goliath crane, the jib crane and the tower crane. In the step of calculating the coordinate information of the threshold point, the GPS coordinates of the respective cranes, information on the rotation angle and tilt of the jib crane boom, and information on the rotation angle of the tower crane boom are substituted in the 3D model of the corresponding crane, and information on the coordinates of a plurality of threshold points which are a criteria of the collision prediction previously designated to the 3D model is calculated for each crane by using the substituted information.

In the step of receiving the position of the crane, GPS values to calculate a rotation angle and tilt of a crane boom of the jib crane and GPS values to calculate a rotation angle of the tower crane are transmitted from at least one first GPS unit installed on a crane boom of the jib crane and at least one GPS unit installed on a crane boom of the tower crane, as well as the GPS coordinates for the Goliath crane, the jib crane and the tower crane. In the step of calculating the coordinate information of the threshold point, information on the rotation angle and tilt of the jib crane boom calculated from the GPS values transmitted from the first GPS unit, and information on the rotation angle of the tower crane boom calculated from the GPS values transmitted from the second GPS unit are substituted in the 3D model of the corresponding crane, and information on the coordinates of a plurality of threshold points which are a criteria of the collision prediction previously designated to the 3D model is calculated for each crane by using the substituted information.

The threshold point of the Goliath crane is a point indicating both ends of a transverse support block installed in a longitudinal direction of the Goliath crane, the threshold point of the jib crane is a point indicating both ends of the jib crane, and the threshold point of the tower crane is a point indicating both ends of the tower crane. The method further comprises an alarm step for making it possible to aurally confirm the collision of the cranes in real time through an alarm or alert message when the minimum neighboring distance between the cranes becomes smaller than a threshold distance and collision between specified cranes is predicted.

In the alarm step, the distance less than the threshold distance is classified into a plurality of distance steps, and the alarm or alert message are differently created every distance step of the minimum neighboring distance to distinguish the alarm or alert message. The method further comprises a monitoring display step for displaying in real time shapes and positions of the respective cranes using the 3D models for the corresponding cranes, in which the transmitted GPS coordinates of the cranes, information on the rotation angle and the tilt of the jib crane, and information on the rotation angle of the tower crane have been substituted. In the monitoring display step, if the minimum neighboring distance between the cranes is smaller than the threshold distance and thus collision between the specified cranes is predicted, the cranes subject to collision are displayed with a specified flickering color or with a color that is different from the color of the cranes that are not subject to collision, so that the cranes subject to collision can be visually confirmed in real time.

In the monitoring display step, the corresponding distance that is smaller than the threshold distance is classified into a plurality of distance steps, and the display color of the cranes subject to collision differs for the corresponding distance step that is smaller than the minimum neighboring distance, or a fact that distance step among the plurality of distance steps that are smaller than the threshold distance includes the cranes subject to collision is displayed in the form of one or a combination of an image, a text, graphics, and a table. ADVANTAGEOUS EFFECTS

According to the system for predicting collision of cranes according to an embodiment of the present invention, the collision between the cranes is accurately predicted by monitoring not only the position of a respective crane but also the rotation angle and the tilt of the crane boom in real time, and the danger of collision is reported to the managers or operators in real time, so that the danger of various kinds of accidents and the resultant damage of manpower and material properties can be greatly reduced.

Also, unnecessary computation is removed to make computation convenient and reduce computation time by completely eliminating the cranes having no possibility of the collision, thereby quickly predicting the collision possibility. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart depicting a process of predicting collision of cranes according to an embodiment of the present invention;

FIG. 2 is a view illustrating the construction of a system for performing the process in FIG. 1 ; FIG. 3 is an exemplary view illustrating a ship construction dock to which the system in FIG. 2 is applied;

FIG. 4 is a view depicting divided regions which are a criteria at a collision predicting step in FIG. 1 ;

FIG. 5 is a view depicting a numbered line segment of each crane in FIG. 4; FIG. 6 is a view depicting a reference point of a crane;

FIG. 7 is a view depicting a threshold point of each crane;

FIG. 8 to 10 are views depicting several threshold distance steps on each crane; FIG. 11 is an exemplary view of an approximate value of a collision feasible area in case of the crane in FIG. 10;

FIG. 12 is an exemplary view modeling a jib crane as a line segment;

FIGS. 13 to 16 are views of crane booms of jib cranes;

FIGS. 17 to 19 are exemplary views explaining calculation of minimum neighboring distance between cranes; and

FIG. 20 is an exemplary views depicting a process of determining whether a line segment of the minimum neighboring distance exists on the line segment in FIGS. 17 to 19. BEST MODE FOR THE INVENTION Hereinafter, a preferred embodiment of the present invention will be explained in detail with reference to accompanying drawings. Before the present method is disclosed and described, one should notice that the terminology used in the specification and any of the claims are not to be interpreted by general meaning commonly known to an ordinary skilled person in the art or definitions in dictionary only, but should be understood as meaning and concept suitable for technical idea of the present invention, on the basis of the principle that an inventor is able to define the concept of a certain term for the purpose of describing his invention in the best way.

Therefore, the embodiments described herein and the construction illustrated in the drawings are for the purpose of describing a particular embodiment only, and are not intended to be limiting or representing all the technical ideas the present invention try to convey. Therefore, one should notice that there are many alternatives, modifications, and variations that can act as a substitute for them at the time of filing. FIG. 1 is a flowchart depicting a crane collision predicting method according to an embodiment of the present invention. FIG. 2 is a view illustrating the construction of a system for performing the method in FIG. 1. FIG. 3 is an exemplary view illustrating a ship construction dock to which the system in FIG. 2 is applied. FIG. 4 is a view illustrating a segmentation region which is a reference region at a collision predicting step in FIG. 1. FIG. 5 is a view of an exemplary in which the respective line segments is numbered. FIG. 6 is a view depicting an exemplary of a crane reference point. FIG. 7 is a view depicting a threshold point of each crane.

First, in a ship construction dock, only several Goliath cranes 10 may be arranged, several Goliath cranes 10 and jib cranes 20 may be arranged, or several Goliath cranes 10, jib cranes 20, and tower cranes 30 may be arranged. In addition, diverse arrangements of the above-described cranes may be provided. Generally, the number of the cranes 10, 20, and 30 arranged in the ship construction dock may be properly determined depending on the ship construction process.

The present method which is performed under the above circumstance will now be described with reference to FIGs. 1 to 3.

A main management unit 120 receives GPS coordinates on the respective cranes from a GPS receiver 110 installed in each of a plurality of cranes, that is, coordinate information comprising latitude, longitude, and altitude of the position in which the GPS receiver 110 is installed (S110).

Next, a prediction unit 123 of the main management unit 120 substitutes the received GPS coordinates of the respective cranes in pre-stored 3D models of the corresponding cranes, and calculates the coordinate information on a plurality of threshold points (e.g. points corresponding to 15, 25 and 35 in FIG. 7) which are collision predicting reference previously designated to the 3D models based on the GPS coordinates (S120).

The GPS coordinates may be a reference point to calculate threshold point coordinates of the crane as FIG. 6. In case the coordinates of the reference point of the crane are obtained, coordinates of the threshold point can be automatically calculated by using the 3D model. The 3D model comprises a size, structure and shape of the crane, and if the reference GPS coordinates of the corresponding crane is substituted for the reference point 100 of the 3D model, a distance between an actual position of the respective cranes 10, 20 and 30 and the respective cranes 10, 20 and 30 can be compared.

For example, the height of a pair of pillars that support both sides of the horizontal support block 11 of the Goliath crane 10 and the length of the horizontal support blocks 11 installed on such pillars are pre-stored in the prediction unit 123, and by substituting the GPS coordinates of the Goliath crane 10 for a specified reference point 100 of the Goliath crane 10 in FIG. 6, the actual position of the Goliath crane 100 having the specified size, structure, and shape and coordinates of the threshold point 15 in FIG 7 are calculated, which may be used as reference data for predicting the collision of the cranes.

After the step S120 of calculating the coordinate information of the threshold point, the prediction unit 123 of the main management unit 120 obtains the line segment connecting coordinates of a plurality of threshold points for each crane, and predicts the collision of the respective cranes by using the minimum neighboring distance between the line segment obtained from the crane to be compared and the line segment obtained from a target crane.

A pair of threshold points previously designated in the prediction unit 123 comprising the first threshold point and the second threshold point of each crane may exist, as shown in FIG. 7. In this instance, the line segment means to connect the first threshold point with the second threshold point. For example, the line segment connecting the coordinates 15 of the threshold point for the Goliath crane 10 shown in FIG. 7, the line segment connecting the coordinates 25 of the line threshold point for the jib crane 20, and the line segment connecting the coordinates 35 of the threshold point for the tower crane 30 are obtained. The minimum neighboring distance between the line segment obtained from the Goliath crane 10 to be compared and the line segment obtained from the jib crane 20 to be compared is calculated to predict the collision possibility between the Goliath crane 10 and the jib crane 20.

In case of the Goliath crane 10, as shown in FIG. 3, the GPS receiver 110 may be installed on both ends of a transverse support block 11 installed in a longitudinal direction of the crane. In this instance, length and height of the transverse support block 11 can be known by using only longitude, latitude, and altitude information received in the GPS receiver 110. The information on the length and height of the transverse support block 11 may be previously stored in the 3D model of the Goliath crane 10. The step S130 of predicting the collision of the crane utilizes divided regions 'regions 1 to 32' which are resulted from by dividing a region (dock area), in which crane works are performed.

For example, the collision possibility of the cranes is predicted by using the minimum neighboring distance between the line segment (line segment

C1 ,1 in FIG. 5) obtained from the crane A in the reference region (A; regions 10 and 11), in which the most recently moved crane A is positioned, and the line segments (C2,1 and C3,1) obtained from the cranes B and C in dangerous regions (B; regions 1 to 4, 9, 12 and 17 to 20) which are outside regions of the reference region (A; regions 10 and 11) and are determined as it possibly collides with the crane A in the reference region (A; region 10 and 11), among the divided regions 'regions 1 to 32'.

In case the boom of the crane B and the boom of the crane C extend over the region (B; regions 1 to 4, 9, 12, and 17 to 20) to which the boom 31 of the crane can extend), the crane B and the crane C are regarded as a crane which has the possibility of collision with the crane A. That is, the cranes comprising the booms extendable over the reference region A and the dangerous region are regarded as a crane which has the possibility of collision with the crane A. In the crane arrangement shown in FIG. 4, comparison times of three different types of crane pairs will now be examined as follows.

First, in case of testing the collision possibility of all pairs of cranes A to F, total 15 times (n*(n-1)/2, n=6) of comparison are required.

Second, in case of comparing the collision possibility of other cranes B to F on the basis of the crane A recently moved, only 5 times (n-1 , n=6) of comparison are required.

Lastly, in case of considering that only cranes B and C which are likely to collide in the dangerous region B is considered in the collision test in the second case, only two times of comparison are required. That is, according to the algorism of the present invention, unnecessary computation is removed to make computation convenient and reduce computation time by completely eliminating the cranes having no possibility of the collision, thereby quickly predicting the collision possibility.

As shown in FIG. 5, the respective cranes is allocated with inherent parameter (CiJ)(I denotes serial number of the crane, and j denotes serial number of the line segment for the crane), and coordinates of the parameters

(Ci j) are compared for each crane to predict the collision possibility. In case of the collision of the pillar of the crane (e.g. C1 ,2) with the boom of the crane (e.g.

C2,1), all coordinates of the pillar are automatically computed through the GPS receiver 110 installed on the pillar and receiving the coordinates, and the minimum neighboring distance between the coordinates and the coordinates of the line segment for the boom of the crane is automatically obtained.

FIG. 12 is a view depicting an exemplary of modeling the jib crane 20 as a line segment. (X1 , y1 , z1) are actual position coordinates of the crane, (X2, y2, z2) are height coordinates of the pillar of the crane, and (X3, y3, z3) are ends coordinates of the boom of the crane which are varied depending upon tilting and turning of the crane.

In order to predict the collision of the cranes, the coordinates of the boom's end of the crane corresponding to (x3, y3, z3) should be firstly calculated.

The relative coordinates (x3, y3, z3) are firstly calculated by letting a start point P (x2, y2, z2) of the boom as an original point so as to obtain the coordinates of the boom's end. Letting a length of the boom being α, a tilt of the boom being Y, and a rotation angle of the boom being θ, the coordinates (x\ y\ z') of the boom's end are represented by those in FIGs. 13 to 16. That is, FIG. 13 to 16 show relative coordinates of the boom's end for the original end P, in cases where the coordinates (x\ y', z') of the boom's end are positioned in fourth, third, second and first quarters of an x-y plane.

The coordinates of the boom's are as follows.

Since the coordinates (x', y', z') of the boom's end are on the basis of the original point P, the coordinates are re-operated on the basis of the position coordinates (x1 , y1 , z1) of the crane, and the results are represented as follows. (x3, y3, z3) = (x' + x1 , y' + y1 , z' + z1 )

The shortest distance between a pair of line segments is calculated, and then it is determined whether the shortest distance reaches a dangerous distance.

Algorithm to obtain the shortest distance between vectors of the given line segment in order to obtain the shortest distance between the line segments.

The algorithm will now be described with reference to FIGs. 17 to 20. (a1 , b1 , c1), (a2, b2, c2), (x1 , y1 , z1) and (x2, y2, z2) shown in FIGs. 17 to 20 correspond to threshold points of the present invention.

First, among line segments of all tests to connect the first (line segment (Line 1) obtained from the crane in the reference region A in FIG. 4 with the second line segment (Line 2) obtained from the crane in the dangerous region B, the shortest line segment (Line 3) of the shortest distance is obtained.

As shown in FIG. 17, if inner products formed between the vector of the shortest line segment (Line 3) and the vector of the first line segment (Line 1) are all "0", and if coordinates (aθ, bθ, cO) and (xθ, yθ, zθ) of both end points of the shortest line segment (Line 3) are positioned on the first line segment (line

1) and the second line segment (Line 2), the shortest line segment is effective, the shortest distance D of the shortest line segment is determined as the minimum neighboring distance between the cranes. For example, FIG. 20 shows a case that the criteria to determine whether the coordinates (aθ, bθ, c0) are positioned on Line 1. That is, letting a distance of Line 1 being 11 , a distance between coordinates (a1 , b1 , c1) of the left end point and the coordinates (aθ, bθ, c0) being I2, and a distance between coordinates (aθ, bθ, c0) of the point and coordinates (a2, b2, c2) of the right end point being 13, it is determined whether this point is deviated from the line segment, if the distances 12 and 13 are longer than 11.

FIG. 18 shows a case where inner products formed between vector of the first line segment (Line 1) and vector of the second line segment (Line 2) are all "0", and the shortest distance line segment, in which both ends are not positioned on the first line segment (Line 1) and the second line segment (Line

2) does not exist.

In this instance, if inner products formed between vector of the first line segment (Line 1) and vector of the second line segment (Line 2) are all "0", and any one of the both end points ((aθ, bθ, c0) and (xθ, yθ, zθ)) are positioned on any one threshold point (x1 , y1 , z1) on the first line segment (line 1) or the second line segment (Line 2), the shortest line segment is effective, the shortest distance D of the shortest line segment is determined as the minimum neighboring distance between the cranes.

That is, the minimum distance is calculated for four threshold points (a1 , b1 , c1 ), (a2, b2, c2), (x1 , y1 , z1 ), and (x2, y2, z2) in this case.

FIG. 19 shows a case where inner products formed between vector of the first line segment (Line 1) and vector of the second line segment (Line 2) are all "0", and there is no the shortest line segment in which any one of both ends ((aθ, bθ, cO) and (xθ, yθ, zθ)) is not positioned on any one threshold point on the first line segment (line 1) or the second line segment (Line 2).

That is, if inner products formed between vector of the first line segment (Line 1) and vector of the second line segment (Line 2) are not all "0", the shortest distance of the shortest line segment D, in which both end points ((aθ, bθ, c0) and (xθ, yθ, zθ)) are positioned on any one threshold pint (a1 , b1 , c1) of the first line segment (Line 1) and any one threshold point (x1 , y1 , z1) on the second line segment (Line 2), is determined as the minimum neighboring distance between the cranes.

Of course, among the distance between (a1 , b1 , c1) and (x1 , y1 , z1), (a1 , b1 , c1) and (x2, y2, z2), (a2, b2, c2) and (x1 , y1 , z1), and (a2, b2, c2) and (x2, y2, z2), this is determined that the distance corresponding to the shortest distance is the distance between (a1 , b1 , c1) and (x1 , y1 , z1).

According to the present invention, since the horizontal approaching distance between the cranes and the vertical approaching distance between the cranes can be considered, the collision prediction can be more effectively performed. On the other hand, if it is assumed that the movement or moving speed of the crane (e.g. body or boom) is about 0.6m/s, it is preferable that the error of judgment of the possibility of collision of the cranes is set to 3m (maximum distance) and one second (maximum time). However, this is merely exemplary, and may be changed to another error judgment basis.

In the collision prediction, the boom of the crane can be tilted or turned in the case of the boom 21 of the jib crane in FIG. 2 or 3, while the boom of the crane can be turned in the case of the boom 31 of the tower crane.

In order to improve the reliability of determining the collision possibility based on the turning and tilting of the crane boom and predicting the collision possibility, the information on the rotation angle and the tilt of the crane boom is received, as well as the GPS coordinates for the position of the crane, in the step S100 of receiving the position of the crane in FIG. 1.

In order to acquire the information on the rotation angle and tilt of the respective crane booms 21 and 31 , the present invention includes a mode in which a sensor is installed in the respective crane booms 21 and 31 , and a mode in which a GPS unit is installed in the booms 21 and 31 to receive the

GPS coordinates.

In case of employing the sensor mode, the information on the rotation angle and tilt of the crane boom 21 of the jib crane is received from the first rotation sensor 130 and the tilt sensor 140 installed on the crane boom 21 of the jib crane, and the information on the rotation angle of the crane boom 31 of the tower crane is received from the second rotation sensor 150 installed on the crane boom 31 of the tower crane, as well as the GPS coordinates for the Goliath crane 10, the jib crane 20 and the tower crane 30, in the step S100 of receiving the position of the crane.

As shown in FIG. 3, since the Goliath crane 10 is moved along a Goliath rail 12, but no separate crane boom exists, only the GPS coordinate information is required. Since the jib crane boom 21 performs upward/downward movement and left/right rotation and movement as the jib crane 20 is moved along the jib rail 22, the first rotation sensor 130 and the tilt sensor 140 are further required in addition to the GPS coordinates. Although the position of the tower crane 30 is fixed without any separate rail, the tower crane boom 31 performs left/right rotation and movement, and thus the second rotation sensor 150 is further required in addition to the GPS coordinates.

In the step S120 of calculating coordinate information of the threshold point, the information on the GPS coordinates of the respective cranes, the information on the rotation angle and tilt of the jib crane boom 21 , and the information on the rotation angle of the tower crane boom 31 are substituted in the 3D model of the corresponding crane, and the information on the coordinates of a plurality of threshold points (e.g. start point and end point of the crane boom) which are a criteria of the collision prediction previously designated to the 3D model is calculated for each crane by using the substituted information. Instead of the sensor mode as described above, GPS units for receiving the GPS coordinates may be installed on the respective crane booms 21 and 31 to obtain the information on the rotation angle or tilt. The installation cost and the repair and maintenance cost may be somewhat greater than those in the communication system using the sensor network as described above, but the GPS units can be effectively used in the system according to the present invention.

In the case of using the GPS, GPS values to calculate the rotation angle and tilt of the jib crane boom 21 and GPS values to calculate the rotation angle of the tower crane boom 31 are transmitted from one or more first GPS units (not illustrated) installed on the jib crane boom 21 and one or more second GPS unit (not illustrated) installed on the tower crane boom 31 , as well as the GPS coordinates for the Goliath crane 10, the jib crane 20 and the tower crane 30, in the step S100 of receiving the position of the crane.

For example, 3D model information on the length, shape, and structure of vertical pillars of the jib crane 20, and the length, shape, and structure of the jib crane boom 21 installed at a specified height of the vertical pillars is pre- stored in the main management unit 120, and the computation of the tilt and the rotation angle can be performed through comparison of reference coordinates obtained from the GPS receiver 110 positioned on the shaft of the tower crane boom 21 that meets the vertical pillars as shown in FIG. 2 with reference coordinates obtained from the GPS unit (not illustrated) installed on one side of the tower crane boom 21.

In addition, it is also possible that a pair of GPS units (not illustrated) may be installed on both ends of the respective crane booms 21 and 31 , or on a shaft part of the crane boom 21 and one end of the crane boom 21 , to compute the tile and the rotation angle. The positions and the number of GPS units (not illustrated) installed in the respective crane booms 21 and 31 can be changed at any time as a design change.

In this instance, in the step (S120) of calculating coordinate information of the threshold point, the transmitted GPS coordinates of the respective cranes, the rotation angle and tilt information of the crane boom 21 of the jib crane calculated through the GPS values transmitted from the first GPS unit (not illustrated), and the rotation angle and tilt information of the crane boom 31 of the tower crane calculated through the GPS values transmitted from the second GPS unit (not illustrated) are substituted for the pre-stored 3D model of the corresponding crane. Coordinate information on the plurality of threshold points which is the criteria of the collision prediction previously designated in the 3D model is calculated for each crane by using the substituted information.

In case of the Goliath crane, the threshold point is a point indicating both ends of the horizontal support block 11 installed in a longitudinal direction of the

Goliath crane 10, the threshold point of the jib crane 20 is a point indicating both ends of the crane boom 21 of the jib crane, and the threshold point of the tower crane 30 is a point indicating both ends of the crane boom 31 of the tower crane.

That is, it is possible to predict the collision by comparing the minimum neighboring distance D (FIGs. 17 to 19) obtained between the line segment of one crane and the line segment of another crane by using all coordinates on the line segment connecting both end points of each crane.

After the collision prediction step S130, a shown in FIG. 2 or 3, the display unit 121 of the main management unit 120 can display in real time shapes and positions of the respective cranes using the 3D models for the corresponding cranes, in which the transmitted GPS coordinates of the cranes, information on the rotation angle and the tilt of the jib crane 20, and information on the rotation angle of the tower crane 30 have been substituted.

Therefore, the actual position of the crane and the 3D model of the crane which is placed in the position can be visually confirmed. Also, in the monitoring display step S140, if the minimum neighboring distance between the cranes is smaller than a threshold distance and the collision between the specified cranes is predicted, the display unit displays the cranes subject to collision with a specified flickering color or with a color that is different from the color of the cranes that are not subject to collision, so that the cranes subject to collision can be visually confirmed in real time.

For example, if the minimum neighboring distance D between the transverse support block 11 of the Goliath crane 10 (Crane F) and the crane boom of the jib crane 20 (Crane E) is smaller than the threshold distance and thus the collision between the Goliath crane 10 and the jib crane 20 is predicted, the 3D models of the Goliath crane 10 and the jib crane 20 among the 3D models of the cranes being displayed are displayed with a red color flickering in a specified period, or with a color different from that of the 3D models of other cranes, so that the cranes subject to collision can be easily discriminated and confirmed. More specifically, only portions C5,1 and C6,2 can be distinguished in color, as shown in FIG. 5.

In the monitoring displaying step S140, the corresponding distance that is smaller than the threshold distance is classified into a plurality of distance steps, and the display color of the cranes subject to collision may differ for the corresponding distance step that is smaller than the minimum neighboring distance D, or the fact in which distance step among the plurality of distance steps that are smaller than the threshold distance includes the cranes subject to collision is displayed in the form of one or a combination of an image, a text, graphics, and a table. For example, as shown in FIGs. 8 to 11 , in the case where the corresponding cranes enter into the collision feasible area, the collision warning area, and the collision emerging area, the 3D models of the corresponding cranes may be displayed with different colors.

Also, it may be displayed in the form of one selected among an image, graphics, and a table, which area among the collision feasible area, the collision warning area, and the collision emerging area the cranes subject to collision are positioned in.

It should be noted that phased classification every collision feasible area shown in FIGs. 8 to 11 is an image which is considered on the horizontal approaching between the cranes in view of the convenient explanation.

The information displayed in the monitoring displaying step S140 can be confirmed by a manager of the main management unit 120, and can be confirmed by an operator terminal 170 including a display unit 171 receiving the information from the main manager 120 and displaying or a safety manger terminal 180 including a display unit 181 receiving the information from the main manager 120.

The operator terminal 170 may correspond to a terminal owned by an operator of the respective cranes, and the safety manager terminal 180 may correspond to a terminal owned by a safety manager managing a working spot in which the crane working is performed.

The information displayed on the display units 171 and 181 comprises information on the cranes subject to collision (e.g. names and positions of the corresponding cranes, operator information of the corresponding cranes, and the like). If collision between specified cranes is predicted, the operators of the cranes or the safety manager of the work spot can immediately recognize such collision and thus can promptly take action to prevent the collision.

The alarm unit 122, if the minimum neighboring distance becomes smaller than the threshold distance and collision between specified cranes is predicted, makes it possible to aurally confirm the collision of the cranes in real time through an alarm or alert message (S150).

This may be notified the operator or safety manager in real time by the manger of the main manager unit 120 and the alarm units 172 and 182 of the safety manager terminal 180 or the operator terminal 170. In the alarm step S150, the distance that is smaller than the threshold distance is classified into a plurality of distance steps, and a different alarm or alert message is provided for a corresponding distance step that is smaller than the minimum neighboring distance.

For example, the threshold distance (which may be set to 3m) may be classified into a collision emerging area (which may be set to 1.5m), a collision warning area (which may be set to 2m), and a collision feasible area (which may be set to 3m). As the calculated minimum neighboring distance is changed from 3m to 1.5m, the information output period may become fast, or a different cautionary message may be provided. For example, in the case where the cranes approach within 3m, a cautionary message "Cranes are entering into a collision feasible area", and in the case where the cranes approach within 2m, a cautionary message "Cranes are entering into a collision warning area". Also, in the case where the cranes approach within 1.5m, a cautionary message

"Cranes are entering into a collision emerging area. One or more relay means 160 (FIG. 2) are installed in some parts of the system 100 according to the present invention to relay between the respective cranes 10, 20 and 30 and the main manager unit 120, signal attenuation, signal loss, and the like, can be effectively prevented, and thus the reliability of prediction of crane collision can be increased. As described above, it is apparent that the system for preventing collision of cranes and monitoring a crane work according to an embodiment of the present invention includes the above-described wireless sensor network (WSN) system and other wireless communication systems, such as a wireless LAN (WLAN), RF system, and the like. The communication network system can be changed at any time to correspond to the optimum conditions for the safety of the system, installation and maintenance expenses, the accuracy of the system, time delay, and the like.

The above-described embodiment is to manage various kinds of cranes as one object. This case can be easily achieved and set, but it is not flexible for altered shape of the crane and processing of the corresponding object. More specifically, in case a new kind of crane is added, a program should be revised to satisfy the shape of the new crane, and an executable file should be again produced.

In order to solve the above cumbersome, each crane may be divided into several parts, and then the respective parts may be managed as a unit object. The crane in question is managed by connecting several unit objects to form the complete crane.

For example, a jib crane includes a platform movable on a rail, a body rotatably mounted on the platform, and a boom pivotably mounted on the body. Therefore, since all movable parts of the crane is presented as a unit part, the jib crane can be divided into at least three unit objects.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

Claims:

1. A method for predicting collision of cranes, comprising the steps of: receiving GPS coordinates for the respective cranes from GPS receivers installed in a plurality of cranes; substituting the GPS coordinates of the respective cranes in three- dimensional (3D) models for the corresponding cranes pre-stored, and calculating coordinate information on a plurality of threshold points which are collision predicting reference previously designated to the 3D models based on the GPS coordinates; and obtaining a line segment connecting coordinates of a plurality of threshold points of cranes, and predicting collision of the respective cranes by using a minimum neighboring distance between the line segment obtained from the crane to be compared and the line segment obtained from a target crane.

2. The method as claimed in claim 1 , wherein in the step of predicting the collision of the crane, the collision of cranes is predicted by using the minimum neighboring distance between a line segment obtained from a crane in a reference region, in which the most recently moved crane is positioned, and a line segment obtained from a crane in a dangerous region which is an outside region of the reference region and is determined as it possibly collides with the crane in the reference region, among divided regions of a region in which crane work is performed.

3. The method as claimed in claim 2, wherein the previously designated threshold point exists in a pair of threshold points comprising the first threshold point and the second threshold point of the crane, and the line segment is a line segment to connect the first threshold point with the second threshold point.

4. The method as claimed in claim 3, wherein in the step of predicting the collision of cranes, among test line segments connecting the first line segment obtained from the crane in the reference region and the second line segment obtained from a crane in the dangerous region, in case where inner products formed between vector of the first line segment and vector of the second line segment are all "0", and both end points of the shortest line segment are positioned on the first line segment and the second line segment, the shortest distance of the shortest line segment is determined as the minimum neighboring distance between the cranes.

5. The method as claimed in claim 4, wherein in the step of predicting the collision of cranes, in case where inner products formed between vector of the first line segment and vector of the second line segment are all "0", and the shortest distance line segment, in which both end points are positioned on the first line segment and the second line segment, does not exist, the shortest distance of the shortest line segment, in which inner products formed between vector of the first line segment and vector of the second line segment are all "0" and both end points of the shortest line segment are positioned on the first line segment or the second line segment, the shortest distance of the shortest line segment is determined as the minimum neighboring distance between the cranes.

6. The method as claimed in claim 5, wherein in the step of predicting the collision of cranes, in case where inner products formed between vector of the first line segment and vector of the second line segment are all "0", and the shortest distance line segment, in which any one of both end points are positioned on the first line segment or the second line segment, does not exist, the shortest distance of the shortest line segment, in which inner products formed between vector of the first line segment and vector of the second line segment are all "0" and both end points of the shortest line segment are positioned on the first line segment or the second line segment, the shortest distance of the shortest line segment is determined as the minimum neighboring distance between the cranes.

7. The method as claimed in any one of claims 1 to 6, wherein the crane comprises at least one of Goliath crane, a jib crane and a tower crane.

8. The method as claimed in claim 7, wherein in the step of receiving the position of the crane, two GPS coordinates are transmitted from GPS receivers installed on both ends of a horizontal support block installed in a longitudinal direction of the crane, in case of the Goliath crane.

9. The method as claimed in claim 7, wherein in the step of receiving the position of the crane, information on a rotation angle and tilt of a crane boom of the jib crane is received from a first rotation sensor and a tilt sensor installed on the crane boom of the jib crane, and information on a rotation angle of a crane boom of the tower crane is received from a second rotation sensor installed on a crane boom of the tower crane, as well as the GPS coordinates for the Goliath crane, the jib crane and the tower crane; and in the step of calculating the coordinate information of the threshold point, the GPS coordinates of the respective cranes, information on the rotation angle and tilt of the jib crane boom, and information on the rotation angle of the tower crane boom are substituted in the 3D model of the corresponding crane, and information on the coordinates of a plurality of threshold points which are a criteria of the collision prediction previously designated to the 3D model is calculated for each crane by using the substituted information.

10. The method as claimed in claim 7, wherein in the step of receiving the position of the crane, GPS values to calculate a rotation angle and tilt of a crane boom of the jib crane and GPS values to calculate a rotation angle of the tower crane are transmitted from at least one first GPS unit installed on a crane boom of the jib crane and at least one GPS unit installed on a crane boom of the tower crane, as well as the GPS coordinates for the Goliath crane, the jib crane and the tower crane; and in the step of calculating the coordinate information of the threshold point, information on the rotation angle and tilt of the jib crane boom calculated from the GPS values transmitted from the first GPS unit, and information on the rotation angle of the tower crane boom calculated from the GPS values transmitted from the second GPS unit are substituted in the 3D model of the corresponding crane, and information on the coordinates of a plurality of threshold points which are a criteria of the collision prediction previously designated to the 3D model is calculated for each crane by using the substituted information.

11. The method as claimed in claim 9 or 10, wherein the threshold point of the Goliath crane is a point indicating both ends of a transverse support block installed in a longitudinal direction of the Goliath crane, the threshold point of the jib crane is a point indicating both ends of the jib crane, and the threshold point of the tower crane is a point indicating both ends of the tower crane.

12. The method as claimed in claim 9 or 10, further comprising an alarm step for making it possible to aurally confirm the collision of the cranes in real time through an alarm or alert message when the minimum neighboring distance between the cranes becomes smaller than a threshold distance and collision between specified cranes is predicted.

13. The method as claimed in claim 12, wherein in the alarm step, the distance less than the threshold distance is classified into a plurality of distance steps, and the alarm or alert message are differently created every distance step of the minimum neighboring distance to distinguish the alarm or alert message.

14. The method as claimed in claim 9 or 10, further comprising a monitoring display step for displaying in real time shapes and positions of the respective cranes using the 3D models for the corresponding cranes, in which the transmitted GPS coordinates of the cranes, information on the rotation angle and the tilt of the jib crane, and information on the rotation angle of the tower crane have been substituted.

15. The method as claimed in claim 14, wherein in the monitoring display step, if the minimum neighboring distance between the cranes is smaller than the threshold distance and thus collision between the specified cranes is predicted, the cranes subject to collision are displayed with a specified flickering color or with a color that is different from the color of the cranes that are not subject to collision, so that the cranes subject to collision can be visually confirmed in real time.

16. The method as claimed in claim 14, wherein in the monitoring display step, the corresponding distance that is smaller than the threshold distance is classified into a plurality of distance steps, and the display color of the cranes subject to collision differs for the corresponding distance step that is smaller than the minimum neighboring distance, or a fact that distance step among the plurality of distance steps that are smaller than the threshold distance includes the cranes subject to collision is displayed in the form of one or a combination of an image, a text, graphics, and a table.