JPS62191393A - Hung-load bracing device on ground detaching in crane - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a device for preventing load swing at the time of breaking the ground (the moment the suspended load leaves the ground) in a crane having a hoistable boom.

[Conventional technology]

In a crane, even if the load is slung at its center of gravity, as the wire is hoisted up by the winch, the position of the top sheave shifts farther away from the angle of rotation due to the elasticity of the boom. Therefore, if the wire is wound up as it is, when the lifting force matches the load (or just before that), the suspended load will leave the ground while swinging in a far direction.

This is why the suspended load swings during lifting.
Not only will this lead to the destruction of the suspended load and surrounding structures, but there will always be workers in the surrounding area, including those who are slinging.
This is extremely dangerous as it can lead to personal injury, especially crushing accidents.

[Problem that the invention seeks to solve]

In order to prevent such accidents, it is necessary for the crane to correct the position of the top sheave in the working radial direction and to control the wire hoisting and lowering by the winch, but in conventional equipment, these control operations cannot be performed independently. As a result, control operations are difficult, and, for example, wire tension increases when the boom is raised and lowered, resulting in the suspended load being cut off the ground without completing position correction.

This invention was made in view of the above-mentioned circumstances, and aims to make it easy to correct the position of the top sheave before cutting the ground, and to appropriately suppress the swinging and shifting movement of the suspended load that occurs during the cutting. It is something to do.

[Means for solving problems]

This invention includes a boom length detection means for detecting the boom length, a boom hoisting angle detection means for detecting the boom hoisting angle θ, a boom hoisting angular speed detection means for determining the boom hoisting angular velocity θ, and a moving speed of the suspended load hoisting wire. The wire moving speed detection means for detecting V is multiplied by the detected cosine value cos θ of the boom heave angle of the boom length L1, and the boom heave angular velocity, and the output L '' cos θ・θ is used as a moving speed command for the hoisting wire. The deviation between the moving speed command value V output from the calculating means and the wire moving speed V output from the wire moving speed detecting means is calculated, and the deviation is calculated when the boom is raised and lowered. servo control means for driving the movement of the hoisting wire so that the load hoisting wire becomes zero.

[Effect]

According to this configuration, when the boom is raised and lowered, the suspended load hoisting wire is automatically hoisted up and lowered 7 while the tension is constant as the boom is raised and lowered.
It is now possible to correct the position of the top sheave before the suspended load cuts off the ground by only raising and lowering the boom.

〔Example〕

First, the present invention will be explained in detail with reference to FIG.

In Fig. 2, 1 is a telescopic boom, 2 is a boom hoisting cylinder, 3 is a boom hoisting wire, 4 is a winch,
5 is a top sheave, and 6 is a boom support shaft.

Here, the boom height (height from the ground to the top sheave 5) H is the boom length, the boom heave angle is θ, and the ground clearance of the boom support shaft 6 is H, then equation (1) is obtained. .

H-L-sin θ ten HF ・ (1) Next, (1
) By differentiating both sides of the equation with time, H,3 becomes −−L′ cosθ−HHH・(2), and the vertical movement speed dH/dt of the top sheave 5 is determined by the boom length L1 heave angle θ and the heave angular velocity dθ/dt It can be calculated from

That is, in this device, the winch drive motor is drive-controlled so that the winding speed V of the wire 3 by the winch 4 matches the vertical movement speed dH/dt of the top sheave 5 calculated based on the above equation (2). By doing so, it is possible to perform a raising and lowering operation with a constant wire tension at all times, thereby realizing position correction of the top sheave 5 through a single raising and lowering operation.

Next, FIG. 1 shows the overall control structure of an embodiment of the present invention.

In FIG. 1, the boom length detection means 7 detects the length of the boom. For example, as shown in FIG. It is composed of a reel 9 for winding according to the reel 9, a potentiometer 10 for detecting the rotation angle of the reel 9, etc.
The potentiometer 10 outputs a signal corresponding to the boom length. Next, the potentiometer 11 detects the rotation angle of the boom support shaft 6, thereby detecting the luffing angle θ of the boom relative to the main body of the crane.

Further, reference numeral 12 denotes an incremental photoelectric encoder, and by being connected to the rotation 1111 of the top sheave 5, the encoder 12 outputs a pulse train corresponding to the rotation of the top sheave 5. This pulse signal is input to the frequency/voltage (F/V) converter 13, and the F/Vi converter 13 outputs a voltage signal corresponding to the winding speed V of the wire 3.

The outputs of these detectors, θ and V are multiplexer 1
4, one of the three data is appropriately selected by the multiplexer 14 and inputted to the analog/digital (A/D) converter 15. The A/D converter 15 sequentially A/D converts the input data and inputs the conversion output to the CPU 16.

The CPU 1B includes a memory 17 for data processing, and the specific operation of the CPU 16 will be described below with reference to the flowcharts shown in FIGS. 3 and 4.

The CPU 16 sequentially takes in the boom length L1, the boom heave angle θ, and the wire hoisting speed V output from the A/D converter 15, and performs subsequent calculations using these detected values (step 100).

First, the CPU 16 calculates the wire hoisting speed command value v (=L-cosθ・(dθ′/dt)) according to the above equation (2) (step 110).The boom angular speed dθ/dt is shown in FIG. It is calculated separately every predetermined time period Δ by interrupt processing.

That is, the CPU 16 captures the boom heave angle value θ output from the A/D converter 15 at every predetermined time Δ (step 150), and stores the captured heave angle θ(1) and the memory 7.
The Δ stored in the previous undulation angle value θ (−Δt)
The boom angular velocity dθ/d is calculated according to the following equation (3).
t is calculated (step 160).

・・・・・・・・・・・・・・・(3) And CPU
16 is the calculated dθ/di and the current detected value θ(1
) are updated and stored in each predetermined storage area of the memory 7 (step 170). Therefore, when the CPU 16 calculates the command value V, the latest boom angular velocity d is stored in the memory 7.
θ/dt is always written.

Next, the CPU 16 compares the thus calculated wire speed command V with the actual wire speed V detected by the photoelectric encoder 12, and calculates the deviation ΔV (step 120).

Δ■鴛v−■・・・・・・・・・(4) “Next, the CPU 16 uses the calculated speed deviation ΔV to calculate the control command V to the flow rate servo valve as shown in the following formula (
Step 130).

v mv +Δv x k --- (5) r (k: servo gain) Then, the CPU 16 outputs the calculated servo command (2) to the digital/analog (D/A) converter 18 (step 140), and performs the undulation operation. If it is not Hiiragi J', the process returns to step 100 and the above-described operation is repeated.

On the other hand, the D/A converter 18 performs D/A conversion on the input servo command v1, and outputs the converted output to the voltage/current (V/I) converter 19. The V/I converter 19 performs V/I conversion on the manually input voltage signal Vt, and outputs a current value corresponding to the voltage value V to the flow rate control servo valve 20.

The flow rate control servo valve 20 in this case is a 4-point, 2-position electromagnetically operated valve, and supplies pressure oil to the winch motor 21 at a flow rate proportional to the input current value.

That is, in this servo control system, the vertical movement speed v (=L-cosθ "X(dθ/dt)) of the top sheave 5 is used as the command value, the hoisting speed V of the wire 3 is used as the feedback signal, and the deviation between these The flow rate to the winch motor 21 is determined so that the flow rate becomes zero, and the winch motor 21 is automatically driven according to the determined flow rate, so that the gap between boom ups and downs and the tension of the wire 3 can always be kept constant. Therefore, if it is found that the top sheave is out of position while the hoisted load is not off the ground, the operator can adjust the top sheave's position by simply hoisting and raising the boom without performing any operations to hoist the wire. Corrections can be made.

In the above embodiments, the calculations according to the present invention are performed by software processing by the CPU, but the calculation section may also be configured by a combination of hardware calculation units such as multipliers and differentiators. Good too.

Further, in the above embodiment, the heave angle θ is detected by the potentiometer 11 and the heave angular velocity dθ/dt is obtained by differentiating the detected heave angle θ. Alternatively, the heave angular velocity dθ/dt may be detected directly by a tachogen type angular velocity sensor, or the output of a low-return encoder provided on the boom support shaft 6 may be detected by frequency/dt. It may be determined by converting the voltage (F/V).

Furthermore, although the above embodiments show the case where the present invention is applied to a crane that performs hydraulic boom hoisting, it is of course applicable to a mechanical crane that uses a winch to hoist the boom.

〔Effect of the invention〕

As explained above, according to the present invention, when hoisting the boom, the load hoisting wire is automatically hoisted up and lowered 7 times with constant tension, so the position of the top sheave before cutting the ground can be easily corrected. As a result, it is possible to minimize the swinging and shifting of the load that occurs when cutting the ground, and as a result, it helps to prevent damage to the suspended load and surrounding structures, as well as personal accidents such as crushing. It has excellent effects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of this invention, FIG. 2 is a conceptual diagram for explaining the basic conversion formula of this invention,
FIGS. 3 and 4 are flowcharts showing specific examples of the operation of the apparatus of the embodiment, respectively. 1...Boom, 2...Boom hoisting cylinder, 3...
- Hanging load hoisting wire, 4... winch, 5... top sheave, 6... boom support shaft, 7... boom length detection means, 8... wire, 9... reel, 10. 1
DESCRIPTION OF SYMBOLS 1... Potentiometer, 12... Photoelectric encoder, 13... F/V converter, 14... Multiplexer, 15... A/D converter, 16... CPU, 17
...Memory, 18...D/A converter, 19...V
/I converter, 2o...flow control servo valve, 21...
Winch drive hydraulic motor. Figure 2 Figure 4

Claims (1)

[Scope of Claims] A crane having at least a boom that can be hoisted, includes a boom length detection means for detecting a boom length, a boom hoisting angle detection means for detecting a boom hoisting angle, and a boom hoisting angular speed detection means for determining a boom hoisting angular speed. and wire moving speed detection means for detecting the moving speed of the hoisting wire; multiplying the detected boom length, the cosine value of the boom heave angle, and the boom hoisting angular speed, and calculating the output as the moving speed of the hoisting wire. a calculation means for outputting a command value; a deviation between the movement speed command value output from the calculation means and a wire movement speed output from the wire movement speed detection means; A device for preventing swinging of a load during ground cutting in a crane, comprising servo control means for moving and driving a load hoisting wire.