JP3252689B2 - Horizontal retraction of crane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane in which a second boom that rotates vertically is installed at the tip of a boom that rises and falls.

[0002]

2. Description of the Related Art In a construction excavator, as shown in Japanese Patent Application Laid-Open No. 4-194122, a second boom that pivots in the vertical direction is installed at the tip of a boom that undulates, and the tip of the second boom is further rotated at that tip. A moving bucket is installed. In this one, pressing the horizontal excavation switch causes the first
The driving speed of the cylinder for rotating the second boom toward the squeezing side, that is, the opening of the control valve of the cylinder is calculated and calculated by the control device based on the angle of the boom. Next, the first boom is commanded upward, and the first boom is raised and lowered.
Set the moving direction and opening for the control valve of the cylinder. As a result, when the excavation work by the bucket is started, horizontal excavation is performed until the scraping end posture.

[0003] That is, the horizontal movement of the bucket in the power shovel involves detecting the boom undulation angle by a detector and calculating and setting the cylinder flow rate. Without successively detecting the position of each cylinder,
Based on the calculation result, the flow rate is flowed into each cylinder in an open loop, and each boom is driven to move the bucket horizontally.

[0004]

In the above-mentioned prior art, since each cylinder is driven based on the angle of the boom, even a slight detection error of the angle gives a large error in the horizontal holding accuracy of the bucket. Accuracy is amplified by the length of each boom.

In addition, since the flow rate based on the calculation result is flowed into each cylinder, and the movement amount of each cylinder is fed back one by one and is not corrected, the leveling accuracy is deteriorated.

An object of the present invention is to improve the horizontal holding accuracy of the tip of the second boom.

[0007]

An object of the present invention is to provide a first cylinder device and a second cylinder device based on a horizontal movement command.
The length of the cylinder device is determined, the initial height of the tip of the second boom is determined from the length, and one of the first cylinder device or the second cylinder device is operated, and Obtaining a current length of the cylinder device, obtaining a target length of the other cylinder device for maintaining the initial height from the length, and operating the other cylinder device according to the target length. Can be achieved by:

[0008] Horizontal retraction method.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The crane includes a swivel 11, which is rotatably mounted on a gantry 10, a first boom 20, a second boom 30, a winch 40, and a hanger 50. The first boom 20 is raised and lowered by a first cylinder device 21 provided between the swivel 10 and the first boom 20. Second
The boom 30 is rotatably installed at the tip of the first boom 20, and is raised and lowered by a second cylinder device 31 provided between the first boom 20 and the second boom 30. Rope 41 of winch 40 installed on second boom 30
Suspends the suspender 50 via the sheave 44 at the tip of the second boom 30.

The first cylinder device 21 and the second cylinder device 31 are provided with a detector 2 for detecting the protrusion of the rod itself.
2, 32 are installed respectively. That is, detector 2
2 and 32 respectively detect L1 and L2.
The detectors 22 and 32 are well-known magnetostrictive sensors.

The control device 70 of the crane controls the first cylinder device 20, the second cylinder device 30 and the like according to the detection values of the detectors 22 and 32, the handle 61 of the command device 60, and the command value of the switch 65. The commander 60 includes turning, operation of each of the cylinder devices 21 and 31, and the winch 40.
There are various handles and switches for instructing the operation of, but description thereof will be omitted.

The lever 61 instructs a change in the distance R from the center of the first boom 20 to the tip of the second boom. When the handle is tilted to one side, the boom is retracted (the distance is increased), and when the handle is tilted to the other side, the boom is pushed (the distance is reduced). When the inclination of the handle 61 is stopped, an operation stop command is issued.

The switch 65 is for instructing whether or not the tip of the second boom 20 needs to be moved horizontally. When the switch 65 is turned on to one side, a horizontal movement command is issued, and when the switch 65 is released, a command not requiring horizontal movement is issued.

When the switch 65 is not turned on, the expansion and contraction of the second cylinder device 31 can be controlled by the lever 61. The lever 62 instructs expansion and contraction of the first cylinder device 22. When the switch 65 is turned on, the lever 6
Only 1 is valid. In addition, a potentiometer is incorporated in the levers 61 and 62, and the operation speed of the cylinder devices 21 and 31 can be commanded by the amount of inclination.

When the switch 65 is turned on, the control device 70 determines the horizontal height at that time, and determines the operation amount of the cylinder devices 21 and 31 using this as a target value. The horizontal height can be obtained from the detection values of the detectors 22 and 32.

The operation will be described with reference to FIG. Switch 6
When 5 is input, the detection values of the detectors 22 and 32 are obtained via the A / D converters 81 and 82, and the initial height H is calculated by the initial height detection element 83 and stored. The initial height H is based on the undulation center of the first boom 20. The initial height H can be determined by geometry.

The initial height H is output to a calculation element 85 for the length of the first cylinder device 21, and a table corresponding to the initial height H is selected. FIG. 3 is a table when the initial height H is 2200 mm. In the table, for each initial height H, a length L1 necessary for horizontal movement corresponding to each L2 is set. The length L2 is obtained from the value obtained by the detector 32, L1 corresponding to L2 is selected, and L1 is output as a target value of the first cylinder device 21. Note that L
1, L2 are not the detection values of the detectors 22, 32, but L1,
Although a predetermined value is subtracted from L2, it is shown as the same for convenience. The target value L2 is also a value obtained by subtracting a predetermined value from L2, but is similarly shown for convenience.

The signal of the lever 61 is supplied to the A / D converter 101,
Multiplier 102 for adjusting the moving speed of the cylinder, D
The signal is supplied to the flow control valve 105 via the / A converter 103. The flow control valve 105 supplies oil to the hydraulic cylinder device 32 at a flow rate proportional to the command value of the A / D converter 103. As a result, the second boom operates according to the direction and speed commands from the lever 61. Now, when a command is given in the retracting direction by the lever 61, the second cylinder device 32 moves in the contracting direction, and the tip of the second boom 30 moves downward.

Therefore, the first cylinder length calculating element 85 is determined by the initial height H from the initial height storage element 83 and the current value L2 by the detector 32 of the second cylinder device 31. The length of the first cylinder device 21 for keeping the tip of the second boom 30 horizontal is extracted from the value indicating the length and output as the target value of the first cylinder device 21.

In order to set the first cylinder device 21 to the target length, the difference between the target value and the current length of the first cylinder device 21 is obtained by the adder 86 as a deviation signal.

After integrating the deviation signal by the integrator 87, the gain is adjusted by the magnification unit 88 to obtain an integral operation amount. The deviation signal is made a proportional operation amount proportional to the magnitude of the deviation by a multiplier 89, and this and the integral operation amount are added by an adder 90.

In order to smoothly maintain the level, the difference between the deviation signal and the output of the first-order lag element 92 of the deviation signal is obtained by an adder 93, and the gain is adjusted by a multiplier 94.
The next delay correction operation amount is obtained. This and the output of the adder 90 are added by an adder 95 to obtain an operation signal of the first cylinder device 21. The output of the adder 95 is an A / D converter 96
To the flow control valve 99 of the first cylinder device 21. The flow control valve 99 controls the flow rate proportional to the operation amount to the first
To the cylinder device 21.

The multiplier 89 is provided in the first cylinder device 2
The flow rate flowing to the first cylinder device 21 is determined in proportion to the magnitude of the deviation between the target value of 1 and the current length of the first cylinder device.

The output of the multiplier 88 integrates the deviation until the target value of the first cylinder device 21 and the current length of the first cylinder device 21 coincide with each other. The flow rate to the first cylinder device 21 is determined.

The output of the multiplier 94 for the first-order delay correction operation amount is used to quickly maintain the height of the tip of the second boom 30 at a constant height, so that the target value of the first cylinder device 21 and the current A tendency of the deviation from the length of one cylinder device 21 to increase or decrease is calculated, and this is used as a control amount. That is, since the output value of the first-order lag is the amount of the deviation before a predetermined time, the difference between the current value of the output of the adder 86 and the output value of the first-order lag of the current value is such that the current value tends to increase. Gives whether it is or is decreasing. By reflecting this tendency value as the operation amount, the length of the first cylinder device 21 can be quickly held at the target value.

As described above, the tip of the second boom 30 is horizontally moved with high accuracy.

In the above embodiment, the length of the first cylinder device 21 is determined according to the length of the second cylinder device 31. However, the length may be reversed.

[0028]

According to the present invention, it is possible to move the suspended load while maintaining the height of the load with high accuracy and accuracy, so that the cargo can be easily loaded.

[Brief description of the drawings]

FIG. 1 is a control block diagram of a crane according to an embodiment of the present invention.

FIG. 2 is a side view of the crane according to one embodiment of the present invention.

FIG. 3 is a relation table of a second cylinder device according to one embodiment of the present invention.

[Explanation of symbols]

10 ... stand, 11 ... swivel, 20 ... first boom, 21
... First cylinder device, 22 detectors, 30 ... Second boom, 31 ... Second cylinder device, 32 ... Detectors, 40 ...
Winch, 50 ... hanging tool.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-67955 (JP, A) JP-A-60-181428 (JP, A) JP-A-61-36425 (JP, A) JP-A-63 165300 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B66C 23/00-23/94

Claims (2)

(57) [Claims] A first cylinder device which is raised and lowered by a first cylinder device;
A second boom is installed at the tip of the boom, a second cylinder device is installed between the first boom and the second boom, and a hanging device is provided from the tip of the second boom. A length of the first cylinder device and the second cylinder device based on a horizontal movement command, and an initial height of a tip of the second boom is determined from the length. And operating one of the first cylinder device and the second cylinder device to determine the current length of the one cylinder device and the other cylinder for maintaining the initial height from the length. Obtaining a target length of the device, and operating the other cylinder device according to the target length. 2. A first cylinder raised and lowered by a first cylinder device.
A second boom is installed at the tip of the boom, a second cylinder device is installed between the first boom and the second boom, and a hanging device is provided from the tip of the second boom. A length of the first cylinder device and the second cylinder device based on a horizontal movement command, and an initial height of a tip of the second boom is calculated from the length. And operating one of the first cylinder device and the second cylinder device to determine a current length of the one cylinder device and the other cylinder for maintaining the initial height from the length. A target length of the device is obtained, a deviation between the target length and the current length of the other cylinder device is obtained, and a difference between the first-order lag output of the deviation and the deviation is applied to proportional and complex integral control based on the deviation. The added command, the other Horizontal retraction method of the crane, characterized in that, to be output to the cylinder device.