JPH1059683A - Crane hook position control method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the positional relation between a boom tip section and a hook constant regardless of the erecting/prostrating actions of a boom. SOLUTION: A boom erection angle is detected by a boom angle detector 11, the distance between a winding drum 3 and an idler sheave provided at a boom tip section is determined based on the detected boom erection angle, and the winding drum 3 is driven to be wound or unwound in the direction to keep the positional relation between the boom tip section and an unused hook constant in response to the change of this distance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane hook position control method and apparatus for controlling the position of unused hooks in accordance with the boom raising / lowering operation of a crane in which a plurality of hooks are suspended at the tip of a boom. Things.

[0002]

2. Description of the Related Art In a so-called floating crane or the like mounted on a barge, two or three hooks having different numbers of ropes are hung at the end of a boom, and these hooks are selectively used according to the load.

In such a crane, when working,
Unused hooks are left suspended in the air, causing them to swing back and forth and left and right due to swiveling and boom up / down operations, causing collisions with other hooks, damage, and the inability to work due to being entangled with other ropes. .

[0004]

As a countermeasure for this point,
Unused hooks may be fixed to the end of the boom using fixing means such as a magnet as shown in JP-A-61-33488, or in a so-called unrolled state where the hooks are wound up to the maximum. Conceivable.

However, in a crane, a hoisting drum for hoisting / lowering a hoisting rope is usually installed on the crane main body, and the distance between the hoisting drum and the end of the boom changes due to the up / down operation of the boom ( Decreases when the boom rises,
Increases when lodging).

Accordingly, the hook is pressed against the tip of the boom due to the boom falling operation, and the tip of the boom or the hook is damaged. On the contrary, the hoisting rope is loosened due to the boom standing operation, and the winding drum is disturbed. There was a problem such as doing.

Accordingly, the present invention provides a crane hook position control method and apparatus capable of maintaining a constant positional relationship between a boom tip and an unused hook irrespective of the boom raising / lowering operation.

[0008]

Means for Solving the Problems The invention of claim 1 (method)
A plurality of hooks are respectively hung by hoisting ropes at the tip of a boom which is mounted on the crane body so as to be able to move up and down, and the hoisting ropes are respectively hoisted and wound by hoisting drums installed on the crane body. In a crane configured so that each hook is raised and lowered by being driven downward, the hoisting angle of the boom is detected, and the hoisting drum and a reference point set on the boom are detected based on the detected boom hoisting angle. The hoist drum is driven up / down in a direction in which the positional relationship between the end of the boom and the unused hook is kept constant according to the change in the distance.

According to a second aspect of the present invention, in the method of the first aspect, the tension of the hoisting rope is detected, the detected rope tension approaches a predetermined value, and the positions of the boom tip and the unused hooks are adjusted. This is for driving the hoisting drum up / down in a direction to keep the relationship constant.

According to a third aspect of the present invention, a plurality of hooks are respectively hung by hoisting ropes at the tip of a boom mounted on the crane body so as to be able to move up and down, and the hoisting ropes are installed on the crane body. Boom angle detecting means for detecting a boom up-and-down angle, and controlling rotation of the hoist drum in a crane which is configured to be driven up and down by the hoisting / lowering drive by the set hoisting drum. Drum control means, and a controller,
The controller calculates (i) a distance between a hoist drum that drives an unused hook and a reference point set on the boom, from the boom angle detected by the boom angle detection means, ii) calculating the moving speed of the reference point based on the amount of change in the distance per unit time;
i) It is configured to output a control signal to the drum control means in accordance with the calculated moving speed.

According to a fourth aspect of the present invention, in the configuration of the third aspect, a rope tension detecting means for detecting a tension of the hoisting rope is provided, and a controller detects the rope tension detecting speed at the calculated moving speed of the reference point. The rope tension detected by the means is corrected so as to approach a preset value, and the control value for the drum control means is calculated.

According to the above method and apparatus, the hoist drum is driven up / down in accordance with the change of the boom undulation angle, and the positional relationship between the boom tip and the hook is kept constant. When the is fixed to the end of the boom, there is no risk that the hook or the end of the boom will be damaged, or the hoisting rope will be loosened and the hoist drum will not be wound.

By the way, various factors such as the boom sway and the slack caused by the weight of the rope cause an error in the measured value of the distance between the hoisting drum and the reference point, and the error may reduce the accuracy of the drum control. There is.

In this regard, according to the method and the apparatus of the second and fourth aspects, the tension of the hoisting rope is detected, and this rope tension is also used as an input parameter for drum control. be able to.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

First Embodiment (See FIGS. 1 to 4) FIG. 1 shows a schematic configuration of a crane to which the present invention is applied.

In FIG. 1, reference numeral 1 denotes a crane main body. A boom 2 is mounted on the crane main body 1 so as to be able to move up and down, a hoisting drum 3 is installed, and a hoisting rope 4 unreeled from the hoisting drum 3. Is passed through a rope guide idler sheave 5 and a boom point sheave 6 provided at the end of the boom, and a hook 7 is suspended by the hoisting rope 4 so as to be able to move up and down.

In an actual crane, a plurality of sets (two to three sets) of the hoisting drum 3, the hoisting rope 4, and the hook 7 are provided.
Although provided, only one set is shown here for easy understanding.

Reference numeral 8 denotes a boom hoisting drum, 9 denotes a boom hoisting rope driven up / down by the boom hoisting drum 8, and 10 denotes a guy cable that supports the boom 2.

At the base end of the boom 2, there is provided a boom angle detector 11 for detecting the undulation angle θ of the boom 2.

FIG. 2 shows the configuration of a control system for controlling the rotation of the hoisting drum 4.

In FIG. 1, reference numeral 12 denotes a hydraulic motor (a hoisting motor) as a drive source of the hoisting drum 4, and the rotational force of the hoisting motor 12 is transmitted to the hoisting drum 3 via a speed reducer 13.

The hoist motor 12 is connected to a hydraulic pump 15 via a hydraulic pilot switching hoist control valve 14.
The switching operation of the hoist control valve 14 causes the hoist motor 12
The rotation direction and speed of are controlled.

The hoisting control valve 14 is switch-controlled by pilot pressure from both a winding-up and a winding-down electromagnetic proportional pressure reducing valve (hereinafter, referred to as a winding-up pressure reducing valve and a rolling-down pressure reducing valve) 16 and 17. The pressure reducing valves 16 and 17 are controlled by a controller 18.

In FIG. 2, 19 is a main relief valve, 20 is a counterbalance valve, and 21 is a hoist drum 3
, A solenoid-proportional brake control valve 22 for controlling the negative brake 21 in response to a command signal from the controller 18, and an auxiliary as a hydraulic pressure source for the brake 21. The hydraulic pump 24 is a relief valve for a brake circuit.

The controller 18 includes the boom angle detector 1
2 receives the boom angle signal from the two pressure reducing valves 16, 1
7 outputs a control signal corresponding to the change in the boom undulation angle θ.

The operation of the present apparatus including the operation of the controller 18 will be described with reference to the flowchart of FIG.

When the hook 7 is not in use, it is cut off so as not to interfere with other hooks (not shown) or entangled with other hoisting ropes, or is fixed to the end of the boom by appropriate means. Position control is performed.

Various data (boom length, position and diameter of the idler sheave 5, position of the hoisting drum 3, drum diameter, etc.) of the crane to be applied are previously input and stored in the controller 18, Using the detected boom angle and these data, distances L0 and L1 between the hoisting drum 3 and the idler sheave 5 set as a reference point on the boom (hereinafter referred to as a drum-sheave distance).
Is obtained by calculation.

At the start of the control, the boom angle is input (step S1).

Next, a drum-to-sheave distance L0 corresponding to the input boom up / down angle θ is calculated using the data on the crane described above (step S).
2).

This calculation method will be described with reference to the schematic diagram of FIG.

L0, L1: distance between drum and sheave θ: boom undulation angle α: angle between boom normal and center of idler sheave Li: length from boom foot to center of idler sheave r1: idler sheave radius r2: drum radius X: Horizontal distance from the boom foot to the center of the drum Y: Vertical distance from the boom foot to the center of the drum Assuming that L0 and L1 are calculated by the following equations.

[0034]

(Equation 1)

In the next step S3, the boom angle is again input, and in step S4, as in step S2, the drum-sheave distance L1 corresponding to the input boom angle is input.
Is calculated.

Based on the difference between L0 and L1, step S5
Then, the moving speed S of the idler sheave 5 is calculated by the following equation. t
Is the control cycle time.

[0037]

S = (L1-L0) / t In the first control cycle, L1 = L0 and S = 0, but from the next cycle, the calculated value L0 of the previous cycle and the calculated value of the current cycle are always obtained. This is a comparison with L1.

Next, in step S6, a pressure reducing valve control current corresponding to the moving speed S is calculated.

When the sheave moving speed S is 0, it is not necessary to drive the hoist drum 3 to the upper side or the lower side, and therefore, the process returns to the step S3 via the step S7.

Subsequently, in step S8, it is determined whether the moving speed S is positive or negative. If the moving speed S is negative (boom standing), the hook 7 needs to be wound up. A brake release signal is output, and a control current calculated by calculation is output to the winding-side pressure reducing valve 16 in step S10.

As a result, the hoisting control valve 14 is switched to the hoisting side, the hoisting motor 12 is turned up, and the hoisting drum 3 is driven to the hoisting side at a speed corresponding to the sheave moving speed S.
Since the hoisting rope 4 is wound up by a required amount, the hook 7
Is fixed to the end of the boom, the slack of the rope 4 is prevented.

If it is determined in step S8 that the sheave moving speed S is correct (boom falling down), the hook 7 needs to be lowered, so that the flow shifts to step S11 to output a negative brake release signal. In S12, the calculated control current is output to the lower pressure reducing valve 17.

As a result, the hoisting control valve 14 is switched to the lowering side, the hoisting motor 12 rotates in the lowering direction, the hoisting drum 3 is driven to the lowering side, and the hoisting rope 4 is wound by the required amount. Since the hook 7 is lowered, there is no possibility that the hook 7 is pressed against the boom tip and the hook 7 is damaged or the rope 4 is broken.

Then, in step S13, the drum-to-sheave distance L1 calculated in the current control cycle is replaced with the previous value L0, and the process returns to step S3, where a series of controls is completed.

Second Embodiment (see FIGS. 5 and 6) Only differences from the first embodiment will be described.

As shown in FIG. 5, a winding-side pressure sensor 25 for detecting the winding-side pressure of the winding motor 12 and a winding-side pressure sensor 26 for detecting the winding-side pressure are provided. The motor inlet pressure and the outlet pressure are determined by the sensors 25 and 26, and the tension T of the hoisting rope 4 is determined by the following equation based on the pressure difference (= motor load).

[0047]

T = K | Pin-Pout | K: proportionality constant Pin: motor inlet pressure Pout: motor outlet pressure The obtained rope tension is inputted to the controller 18, and based on the inputted rope tension, idle sheave is performed. The moving speed S is corrected.

The corrected moving speed S 'is obtained by the following equation.

[0049]

S ′ = S + F (Tt−T) Tt: Target rope tension set in advance F: Function for applying PID control to Tt−T FIG. 6 is a flowchart showing the operation of the second embodiment. Will be described together.

In steps S1 to S5, the boom angle input and the drum-sheave distance L
After the 0 calculation, the boom angle input, the drum-sheave distance L1 calculation, and the sheave moving speed S calculation are performed, step S6 is performed.
, The inlet pressure Pin and the outlet pressure Pout of the hoist motor 12 are input.

Next, in step S7, the tension T of the hoisting rope 4 is calculated from the difference between the motor inlet / outlet pressures.
In step 8, the corrected sheave moving speed S 'of the idler sheave 5 is obtained from the value of the rope tension T.

Then, in step S9, a pressure reducing valve control current corresponding to the corrected sheave moving speed S 'is calculated.
As in the first embodiment, the positive / negative determination of the sheave moving speed S 'is performed (step S10). If the determination is negative, the negative brake release signal is output (step S12), and the output to the winding upper pressure reducing valve 16 is shifted (step S13). If negative, the negative brake release signal is output (step S14), and the lower pressure reducing valve 17
After shifting to the output to step S15, L0 is changed to L1.
(Step S16), and returns to Step S3.

According to the second embodiment, the hoisting rope 4
Since the rope tension is detected and this rope tension is also used as an input parameter for drum control, the accuracy of hook position control can be improved.

Other Embodiments (1) In both embodiments, the operation of the boom raising / lowering operation lever is detected as a material for determining whether the boom 2 has been raised / lowered or whether the boom has been raised or lowered. Is also good.

(2) In both embodiments, the negative brake 21
Is released only when the drum is driven, but during control,
The brake 21 may be always released.

(3) In the second embodiment, the tension of the hoisting rope 4 is directly measured by a load sensor or a torque sensor.
It may be detected.

(4) In the above embodiments, the hydraulic crane in which the hoisting drum is driven by a hydraulic motor is applied. However, the present invention can also be applied to an electric or mechanical crane.

[0058]

As described above, according to the present invention, the hoist drum is driven up / down according to the change in the boom undulation angle, and the positional relationship between the boom tip and the hook is kept constant. When the unused hook is fixed to the end of the boom, there is no possibility that the hook or the end of the boom will be damaged, or the hoisting rope will be loosened and the hoist drum will not be wound.

According to the second and fourth aspects of the present invention, since the tension of the hoisting rope is detected and this rope tension is also used as an input parameter for drum control, the accuracy of hook position control can be improved. .

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of a crane to which a first embodiment of the present invention is applied.

FIG. 2 is a diagram showing a configuration of a control system of a hoist drum in the embodiment.

FIG. 3 is a flowchart for explaining the operation of the embodiment.

FIG. 4 is a diagram for explaining each element for calculating a distance between a hoist drum and an idler sheave in the embodiment.

FIG. 5 is a diagram illustrating a configuration of a control system of a hoist drum according to a second embodiment of the present invention.

FIG. 6 is a flowchart for explaining the operation of the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Crane main body 2 Boom 3 Hoisting drum 4 Hoisting rope 5 Idler sheave as a reference point set on the boom 7 Hook 12 Hoisting motor constituting drum control means 14 Hoisting control valves 16, 17 Electromagnetic proportionality Pressure reducing valve 18 Controller 25, 26 Pressure sensor for determining rope tension

Claims (4)

[Claims] A plurality of hooks are respectively suspended by hoisting ropes at the tip of a boom mounted on the crane body so as to be able to move up and down, and the hoisting ropes are respectively wound by hoisting drums installed on the crane body. In a crane that is configured to be driven up and down to raise and lower the hooks, the boom up / down angle is detected, and from the detected boom up / down angle, the hoisting drum and the boom are set on the boom. Characterized in that the hoist drum is driven up / down in a direction in which the positional relationship between the boom tip and the unused hook is kept constant according to the change in the distance. Hook position control method. 2. The crane hook position control method according to claim 1, wherein the tension of the hoisting rope is detected, the detected rope tension is brought close to a preset value, and the boom tip and the unused hook are connected. A hoist position control method for a crane, wherein a hoist drum is driven to hoist / unwind in a direction to maintain a constant positional relationship. 3. A plurality of hooks are respectively suspended by hoisting ropes at a tip end of a boom mounted on the crane body so as to be able to move up and down, and each hoisting rope is hoisted by a hoisting drum installed on the crane body. A crane configured to be driven down to raise and lower the hooks, a boom angle detection unit that detects a boom undulation angle, a drum control unit that controls rotation of the hoisting drum, and a controller. The controller comprises: (i) calculating a distance between a hoisting drum for driving an unused hook and a reference point set on the boom, based on the boom angle detected by the boom angle detecting means; (Ii) calculating the moving speed of the reference point based on the amount of change in the distance per unit time; and (iii) calculating the driving speed in accordance with the calculated moving speed. Hook position control device of the crane, characterized in that it is configured to output a control signal to the control means. 4. A crane hook position control device according to claim 3, further comprising a rope tension detecting means for detecting a tension of the hoisting rope, wherein the controller determines the rope tension by calculating the moving speed of the reference point. A hook position control device for a crane, characterized in that a control value for a drum control means is calculated by adding a correction in a direction in which a rope tension detected by a detection means approaches a preset value.