JP2000112524A - Method and device for controlling traveling of gantry crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for controlling the traveling of a gantry crane for realizing highly precise control with a simple constitution. SOLUTION: At the time of traveling a gantry 4 on a desired path by driving wheels 1 and 1 of both legs 2 and 2 of the gantry, the position of a fixed place on ground and the position of the gantry are measured by satellite radio waves, and the measured position of the gantry is corrected based on the simultaneously measured position of the fixed place, and the driving of the wheels 1 and 1 is controlled based on the corrected position of the gantry.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling the traveling of a gantry crane such as an RTG (rubber tire type transfer crane) traveling on a trackless track, and more particularly, to a highly accurate control with a simple configuration. The present invention relates to a gantry crane travel control method and apparatus.

[0002]

2. Description of the Related Art A trackless gantry crane (also referred to as a portal crane) travels a gantry provided with a girder between two legs having wheels. The wheels of both legs each have a traveling motor and can be driven independently. Further, rubber tires (rubber tires) are used for the wheels. That is, the gantry crane has a degree of freedom for moving the gantry in any direction. However, on the other hand, even if the gantry is to travel along the planned route, the gantry may run off the planned route.
If the gantry deviates from the planned route, the control position of the trolley in the girder will deviate from the intended ground position. Therefore, it is necessary to control the driving of each wheel so that the traveling trajectory of the gantry does not deviate from the planned route.

Conventionally, for example, when a gantry is driven in a straight line, an angular displacement meter such as a gyro detects relative angular displacement caused by traveling, and the driving amount of the wheels of both legs (such as a gyro) is eliminated so as to eliminate the angular displacement. The running speed of each leg is controlled. However, such an angle control alone cannot return the gantry to the planned straight line when the gantry runs parallel to and deviates from the planned straight line. In addition, since the angular displacement meter has a drift, the angle shift increases. Therefore, an absolute position sensor that detects the absolute position of the gantry is embedded on the ground (or an index is placed on the ground so that the index is detected from the gantry), and correction control is performed using the gantry position detected when passing. To return the gantry to the expected straight line.

In the prior art disclosed in Japanese Patent Publication No. 7-38133, a traveling reference point is provided at predetermined intervals in a yard, and a reference point signal obtained from the traveling reference point and a measuring device driven by wheels are used. By combining the measured traveling speed and the traveling angle measured by the gyro, the shift amount is calculated and the trajectory is corrected according to the shift amount. This technique also corrects a relative displacement that is always detected based on an absolute position detected when passing an index.

[0005]

The prior art uses a sensor for detecting relative displacement and an absolute position sensor in combination. For example, in the technique of the above-mentioned document, three types of detection devices, a travel reference point detection device, a travel speed detection device, and a travel direction angular velocity detection device, are used. For this reason, the device configuration becomes complicated, and the accuracy of each of the detection devices collectively adversely affects the accuracy of the trajectory correction.

In the prior art, a large number of indices (running reference points) must be installed in a yard in a regular arrangement.
The labor (labor, time, cost, etc.) becomes enormous.

It is an object of the present invention to solve the above-mentioned problems and to provide a gantry crane traveling control method and apparatus capable of performing highly accurate control with a simple configuration.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, a method of the present invention is to provide a method for driving a gantry along a desired route by driving the wheels of both legs of the gantry, respectively. And, respectively, to perform positioning using satellite radio waves, correct the measured position of the gantry based on the position of the fixed position measured simultaneously, and drive-control each wheel based on the corrected position of the gantry.

In order for the gantry to travel on a straight path,
The position of the gantry may be represented by coordinates using a coordinate axis perpendicular to the linear path, and the drive control may be performed so that the coordinates match the coordinates of the linear path.

[0010] The apparatus of the present invention is a control device for driving the wheels of both legs of the gantry to travel the gantry on a desired route. A positioning system using satellite radio waves at a fixed place on the ground and on the gantry. Of a receiving station, a calculation unit for correcting the position of the measured gantry based on the position of the fixed position measured simultaneously, and a control unit for driving and controlling each wheel based on the corrected position of the gantry. It is.

[0011]

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

Here, it is assumed that the method of the present invention is used to control the gantry of an RTG (rubber tire type transfer crane) to travel along a predetermined straight path as shown in FIG. The travel control device shown in FIG. 2 is used for the control.

As shown in FIG. 1, the RTG runs a gantry 4 having a girder 3 provided between two legs 2 and 2 having wheels 1 and 1, respectively. Each of the wheels 1 and 1 has a traveling motor (not shown) and can be independently driven. Rubber tires are used for the wheels. 5 is a geostationary satellite, 6 is a fixed station, 7 is a mobile station,
Reference numerals 8 and 8 denote trajectories of the wheels 1 and 1 when the gantry 4 runs straight in the direction of the arrow.

As shown in FIG. 2, the traveling control device for straight traveling is fixedly provided on the ground (including on a building) and has a receiver 21 of a fixed station 6 which performs positioning by satellite radio waves.
And a receiver 22 of the mobile station 7 mounted on the gantry 4 for performing positioning by satellite radio waves, and a position for correcting the position of the gantry measured by the mobile station 7 based on the position of the fixed station 6 simultaneously measured by the fixed station 6. The correction operation unit 23 and the corrected position of the gantry are determined by using a straight line X
A linear travel control unit 24 that represents a command to match the X coordinate of the gantry with the X coordinate of the straight path, expressed by Y orthogonal coordinates.
Consists of The fixed station 6 is provided with a transmitter 25 for transmitting the information on the position of the fixed station, and the gantry 4 is provided with a corresponding receiver 26. Gantry 4
Are provided with two traveling motors 27, 27 for driving the wheels 1, 1 of both legs, respectively, and a traveling motor control device 28 for controlling these traveling motors 27, 27. Drive control of the wheels 1 and 1 can be performed by a command.

In this embodiment, the mobile station 7 is located on the girder 3 near the fixed station.
May be placed anywhere on the gantry 4. Since the position of the gantry 4 is represented by the position of the mobile station 7, the path of the gantry 4 is represented by the path of the mobile station 7. The fixed station 6 may be installed anywhere, but the exact position of the fixed station 6 is measured at the time of installation.

Next, the operation of the travel control device will be described.

The fixed station 6 and the mobile station 7 always perform positioning by satellite radio waves. Here, a GPS (wide area positioning system) is used as a positioning system using satellite radio waves. GPS
Is obtained by capturing radio waves from a plurality of (for example, four) geostationary satellites 5 with a receiver, and thereby determining the position (latitude and
(Longitude / altitude). GP
S can detect the coordinates of the earth coordinate system, that is, the absolute position, in real time. However, the positioning accuracy by GPS alone is about 10 m, which does not hinder car navigation or the like, but is insufficient for running control of a gantry crane requiring an accuracy of several cm or several mm. Therefore, DGPS (differential positioning) using a fixed station and a mobile station is performed.

The position of the fixed station measured by the fixed station 6 (or the difference between the known installation position of the fixed station and the measured position)
Is transmitted from the transmitter 25 to the receiver 26 at all times. The position correction calculation unit 23 obtains a difference between the known fixed station installation position and the received fixed station position (or uses the received difference), and uses the difference as a correction value by the mobile station 7 to make the fixed station 6
At the same time, the position of the measured gantry is corrected.

The linear travel control unit 24 determines the position of the gantry expressed in the GPS coordinate system by using an X-axis whose linear path is parallel to the Y-axis.
Converted to Y orthogonal coordinates and represented. Further, the straight traveling control unit 24
Issues a command to the traveling motor control device 28 so that the X coordinate of the gantry matches the X coordinate of the straight path. The traveling motor control device 28 determines the traveling motors 27, 27 in accordance with this command.
Control.

In FIG. 3, it is assumed that when the gantry is moved upward in the drawing, the position of the gantry is shifted in advance to the right in the drawing from the planned straight path 31. At this time, the X coordinate of the gantry becomes larger than the X coordinate of the straight path. The linear travel control unit 24 issues a command to reduce the X coordinate of the gantry to match the X coordinate of the linear path 31.
7 is driven larger than the traveling motor 27 of the left wheel 1. Therefore, the gantry moves to the left in the figure. If the X coordinate of the gantry becomes smaller than the X coordinate of the straight path 31, the traveling motor 27 of the left wheel 1 in the figure is driven to be larger than the traveling motor 27 of the right wheel 1 in the figure, and the gantry moves rightward in the figure. I will stop by. As a result, the deviation between the X coordinate of the gantry and the X coordinate of the straight path 31 is eliminated, and the traveling trajectory 32 of the gantry approaches the straight path 31 without limit.

Next, it is assumed that the X coordinate of the gantry matches the X coordinate of the straight path 31, but the front direction of the gantry (the direction orthogonal to the girder) is inclined with respect to the straight path 31. Since the X coordinate of the gantry matches the X coordinate of the straight path 31, the traveling motor 2 of the left and right wheels 1, 1
7, 27 are driven equally. For this reason, the gantry travels in a direction inclined with respect to the straight path 31. As a result, the X coordinate of the gantry does not match the X coordinate of the straight path. At this time, the X coordinate of the gantry is set to the straight path 31.
Is controlled so as to match the X coordinate of the gantry, so that the front direction of the gantry is corrected so as to match the straight path 31, and the inclination is eliminated in the same manner as the above-described displacement.

In this way, since the positional deviation and the angular deviation are eliminated, the straight running control along the planned straight route 31 is achieved. For reference, FIG. 3 shows a trajectory of a gantry according to the related art. 33 is a traveling locus when the angle deviation increases, and 34 is a traveling locus when the positional deviation is not eliminated.

As described above, according to the traveling control method of the present invention, a fixed station and a mobile station are required, but they perform positioning by common satellite radio waves, and the variables to be detected are the same. Therefore, the correction is easy, and the accuracy and the error at the moment are the same, so that there is no adverse effect on the overall accuracy. Therefore, the device configuration is simplified and the accuracy is improved as compared with the conventional technology in which a plurality of sensors having different detected variables are used in combination. In addition, since the fixed station may be located anywhere on the ground, the configuration of the apparatus is simplified and the installation of the apparatus is simpler than in the prior art in which a large number of indices need to be installed in a regular arrangement to improve accuracy. Time (labor, time, cost, etc.) is greatly reduced.

In the case of the straight running control, since the coordinate axis perpendicular to the straight path is used, if only the shift component appearing on the coordinate axis is controlled, the position shift and the angle shift are eliminated, and the straight running can be performed. Easy.

[0025]

The present invention exhibits the following excellent effects.

(1) Since the apparatus configuration is simplified, installation and maintenance are facilitated, and costs can be reduced.

(2) Since the position accuracy of the gantry is improved, the position accuracy of the trolley is also improved.

[Brief description of the drawings]

FIG. 1 is a diagram of an RTG showing one embodiment of the present invention;
The front view of the gantry and the conceptual diagram of satellite radio waves are superimposed on the ground plan.

FIG. 2 is a block diagram of a travel control device of the RTG of FIG. 1;

FIG. 3 is a plan view showing a straight path and a traveling trajectory of the gantry according to the present invention and the prior art.

[Explanation of symbols]

 Reference Signs List 1 wheel 2 leg 3 girder 4 gantry 5 geostationary satellite 6 fixed station 7 mobile station

Continued on the front page F term (reference) 3F204 AA03 CA01 CA07 DA08 DB02 DC04 DD14 GA04 5H301 AA01 AA10 BB06 CC03 CC06 DD05 DD17 EE31 FF08 FF11 FF15 HH03 QQ06

Claims (3)

[Claims] When driving the gantry along a desired route by driving the wheels of both legs of the gantry, positioning is performed by satellite radio waves at a fixed point on the ground and on the gantry, and the position of the gantry is determined. A travel control method for a gantry crane, wherein the gantry crane is corrected based on the position of a fixed portion measured at the same time, and drive-controls each wheel based on the corrected position of the gantry. 2. In order for the gantry to travel along a straight path, the position of the gantry is represented by coordinates using coordinate axes perpendicular to the straight path, and the drive control is performed so that the coordinates match the coordinates of the straight path. The travel control method for a gantry crane according to claim 1, wherein: 3. A control device for driving wheels of both legs of the gantry to travel the gantry on a desired route, wherein a receiving station of a positioning system using satellite radio waves is provided at a fixed place on the ground and on the gantry, respectively. A gantry crane, comprising: a calculation unit that corrects the measured position of the gantry according to the position of the fixed position that is simultaneously measured; and a control unit that drives and controls each wheel based on the corrected position of the gantry. Travel control device.