JPS62201791A - Automatic horizontal shifter for hung load of 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] [Field of Industrial Application] This invention relates to a crane having a boom that can raise and lower, and to improve the weldability of a device that automatically horizontally moves a suspended load from the tip of the boom. The aim is to

[Conventional technology]

In this type of crane, when hoisting the boom, the height of the suspended load above the ground is often maintained constant from the viewpoint of work safety. In this hoisted load horizontal movement operation, the vertical height of the hoisted load will fluctuate if only the hoisting operation is performed, so the winch must be hoisted and lowered in parallel, which poses the problem of difficult operation control. be.

Therefore, as one conventional technique for horizontally moving a suspended load with easy operation, there is, for example, Japanese Patent Application Laid-Open No. 75383/1983. This crane hook ground clearance control method eliminates the need for manual winch operation during horizontal movement of hoisted loads by controlling the amount of wire payout according to the amount of vertical movement of the hook due to boom hoisting and expansion/contraction. I have to.

[Problem that the invention seeks to solve]

By the way, in the case of a crane, the number of wires to be wrapped around the hoisting wire can be changed depending on the normal work conditions (lifted load amount, fine operability, cycle time, etc.), but if the number of wires to be wrapped is increased, Even if the moving speed of the wire is increased by rotating at high speed, the lifting speed of the hook cannot be increased. Conversely, when the boom is raised and lowered at the same angular velocity, when the levitation angle is small, that is, when the boom is lying on the ground, the boom top lifts and descends faster than when the levitation angle is large.

Therefore, when the number of wires to be hung is large or the boom hoisting angle is small, even if you try to make the hook's lifting speed follow the lifting speed of the boom top in the height direction, the wire moving speed will exceed the limit speed. In this case, the suspended load does not move horizontally. For example, when the wire travel speed exceeds a limit value, the suspended load will suddenly begin to fall and in extreme cases may come into contact with the ground. but,
This is difficult for the driver to predict, and may lead to damage to the suspended load and surrounding structures, as well as personal injury to workers such as slingers.

This invention was made in view of the above-mentioned circumstances, and aims to improve safety by making it possible to always move suspended loads horizontally.

[Means for solving problems]

In this invention, in an automatic horizontal movement device for a crane that moves a suspended load horizontally by controlling the payout of a suspended load lifting wire in response to the ups and downs of the boom, the cosine value COSθ of the boom length L1 and boom ups and downs angle is provided. and a calculation means for performing calculations with a value nLcosθ multiplied by the number of wire windings n as a divisor and a limit value V of the wire moving speed as a dividend; and an output of the calculation means that outputs the boom heave angular speed input as the target value. and a control means for controlling boom raising and lowering based on the output of the limiter means.

[Effect]

According to this configuration, when the vertical movement speed of the top end of the boom exceeds the wire movement speed limit, the boom hoisting speed is limited in accordance with the wire movement speed limit. It is also possible to move suspended loads horizontally.

〔Example〕

Fig. 3 shows a partial side view of the crane, in which 1 is a boom that can be raised and retracted, and a hook 4 is suspended from a top sheave 2 via a wire 3. The wire 3 is wound up and let out by forward and reverse rotation of a winch 5 provided at the base end of the boom, thereby raising or lowering the hook 4 in the vertical direction.

Here, the boom height H (height from the ground to the top sheave 2) is expressed by <1) where L is the boom length, θ is the boom heave angle, and H is the height of the boom support shaft 6 above the ground.

HmL11sinθ+H-(1) Next, by time-differentiating both sides of equation (1), the vertical movement speed dH/dt of the top sheave 2 can be obtained.

Now, if the number of times the wire 3 is multiplied is n, the required wire speed Vw to move the suspended object horizontally is d θ m n * L * cos θ ---
・-(3)t. Here, if the control limit upper limit speed of the wire 3 by the winch 5 is vWM, it will be impossible to horizontally move the suspended load unless the wire speed vw is within the limit speed Vwi. Therefore, in this device, by performing limit control so that the boom hoisting angular velocity dθ/dt satisfies the following equation (4), it is possible to horizontally move the suspended load even when dI(/dt>v,M). That's what I do.

Next, the configuration of an embodiment of the present invention will be described according to FIGS. 1 and 2. FIG. 1 shows an example of the servo control system 10 for the heave angular velocity dθ/dt and the calculation unit 20 that calculates the limit value CL of the heave speed, and FIG. 2 shows an example of the servo control system 30 for the hook height. This shows that.

First, the configuration of the calculation section 20 will be explained.

The boom length detection means 21 detects the length of the boom, and includes, for example, a wire 7 whose one end is fixed to the top of the boom 1 as shown in FIG. It is comprised of a reel 8, a potentiometer 9 that detects the rotation angle of the reel 8, and the potentiometer 9 outputs a signal corresponding to the boom length. In this case, since the boom is extendable and retractable, the detection means described above was used, but in the case of a crane with a fixed length boom such as a lattice boom, it is recommended to simply set the boom length in advance. do it.

The wire winding number setter 22 is used to set the wire winding number n, and the set wire winding number n is input manually to the multiplier 25. The multiplier 25 multiplies the input boom length and wire multiplication number n, and inputs the calculation result nL to the multiplier 27.

Next, the potentiometer 23 detects the rotation angle of the boom support shaft 6 to control the boom 1 relative to the crane body.
The detected boom angle θ is input to the cosine generator 26, which generates C
After being converted into OSθ, it is input to the multiplier 27.

The multiplier 27 multiplies the output nL of the multiplier 25 and the output COSθ of the cosine generator 26, and the calculation result nLcos
θ is input to the divider 28. The control limit upper limit speed vwM of the wire 3 by the winch 5 is input from the wire limit speed setting device 24 to the other input terminal of the divider 28, and the divider 28 performs division with nLcosθ as a divisor and vWM as a wave divisor. and the calculation result is y, M/n L
cos θ as the limiter 12 of the heave speed servo control system 10
Enter. That is, in the calculation unit 10, the above (4
) The limit value CL of the boom hoisting angular velocity dθ/dt(-ω) corresponding to the wire limit speed vWM is calculated, and this limit value cLM is input to the limiter 12.

Next, the configuration of the hoisting speed servo control system 10 will be explained.

The heave angular velocity command device 11 sets the target value ω of the heave angular velocity ω. In this case, for example, a potentiometer is linked to the hoisting operation lever, and the lever displacement information X output from the potentiometer is used as the hoisting angular velocity command value ω. We adopted a configuration that converts to . This heave angular velocity command value ωC
is input to the limiter 12.

The limiter 12 limits the input signal ω to the upper and lower limits ±CLM when the input heave angular velocity command value ω exceeds a predetermined upper and lower limit value CLMG, and this upper and lower limit value ±cLM
is the output C(”V H/
The variable M is set by n L Cos θ). The heave angular velocity command ω sliced by the limiter 12. L is manually added to the addition point 13.

At addition point 13, the human-powered heave angular velocity command ωC1,
and the feedback signal dθ/ output from the differentiator 14
The deviation Δω (-ωCL-ω) from dt(■ω) is taken. This deviation Δω is passed through the servo amplifier 15 to obtain a gain k. Flow control valve 1 of the cylinder for rear elevation given
6 will be man-powered. The flow rate control valve 16 adjusts the pressure oil flow E to be supplied to the undulation cylinder 7 according to the input deviation and Δω.
By determining ilQ, the expansion and contraction of the undulating cylinder 7 is controlled. The boom 18 is raised and lowered by the expansion and contraction of the raising and lowering cylinder 17. The up-and-down angle θ of the boom 18 is detected by the potentiometer 23, and this detected value θ is input to the differential input 14, and the differential output dθ/dt(
-ω) is input to the addition point 13 as a feedback signal. That is, in this luffing angular velocity servo system 10, the boom angular velocity command value ω is limited by the limiter 12 to within the limit value lcLM1. , follow-up control is performed.

Next, the configuration of the hook position servo control system 30 will be explained.

In FIG. 2, a hook height setter 31 is used to set a target value Hkc of the ground height H of the hook 4 (see FIG. 3), and this target value H5° is manually input to the addition point 32. The addition point 32 takes the deviation ΔH (-c Hko-Hk) between the input target value H and the feedback signal Hk. This deviation ΔH is the servo amplifier 3
3, the gain K11 is applied to the flow rate control valve 34 for driving the winch motor. The flow rate control valve 34 drives and controls the winch motor 35 by determining the flow rate of pressure oil to be supplied to the winch motor 35 according to the input deviation signal KnΔH. As a result, the winch 5 is rotated and the wire 3 is wound or fed out. The moving length IIw of the wire 3 is detected by a detector (not shown), and the detected value is input to the calculator 36.

The calculator 36 calculates the ground height Hk of the hook 4 according to the following formula, and uses the calculated value Hk as a feedback signal to add to the addition point 3.
Manpower to 2.

Hk-Lφs[nθ+H8-g, -(5) However,
H is the height of the boom support shaft 6 above the ground (see Figure 3).

That is, the hook height servo control system 30 adjusts the amount of wire movement g by the winch so that the deviation between the hook height setting value H and the feedback signal Hkc becomes zero when the boom is raised or lowered.
1.

In the device of this embodiment, the heave angular velocity command value ω is used during horizontal movement of a suspended load. is limited to a predetermined limit speed CLM″r corresponding to the wire limit speed V, and the boom hoisting angular velocity is servo-controlled in accordance with the command value CLM that has been limited, and the hook position servo control system 30
Accordingly, the wire payout amount is controlled in accordance with the vertical movement amount of the hook.

Therefore, if the suspended load cannot be moved horizontally unless the wire is moved at a speed exceeding the limit value, the boom side will be limited to a speed corresponding to the wire movement limit speed and will be raised or lowered, and such folding will occur. It is also possible to move suspended loads horizontally.

In the above embodiment, the calculation for determining the heave angular velocity limit value CLM is performed by a combination of hardware calculation units such as a multiplier and a divider.
Similar calculations may be performed by software processing by U.

Furthermore, in the embodiment described above, the heave angle θ is detected by the potentiometer 23 and the feedback signal dθ/dt of the heave angular velocity is obtained by differentiating the detected heave angle θ. It can also be detected by a pendulum-type inclinometer, etc., and the heave angular velocity dθ
/dt may be directly detected by a tachogenerator-type angular velocity sensor, or may be obtained by frequency/voltage (F/V) conversion of the output of a rotary encoder provided on the boom support shaft 6.

〔Effect of the invention〕

As explained above, according to the second invention, when the moving speed of the hoisting load lifting wire exceeds the control limit value, the boom hoisting speed is limited in accordance with the wire moving limit speed. The suspended load can be constantly moved horizontally without sudden lifting or lowering of the load, thereby effectively preventing damage to the structures surrounding the suspended load as well as personal injury to workers such as the person slinging the load. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the configuration of a hoisting speed servo control system and a limit angular velocity calculating section in an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of the structure of a hook position servo control system of the device according to the embodiment. , FIG. 3 is an external side view showing an example of a crane to which the present invention is applied. 1... Boom, 2... Top sheave, 3... Wire, 4... Hook, 5... Winch, 6... Boom support shaft, 7... Wire, 8... Reel , 10...
・Huffing speed servo control system, 11...Huffing angular speed command unit, 12...Limiter, 13.32...Addition point, 14
...Differentiator, 15°33...Servo amplifier, 16.
34...Flow rate control valve, 17...Luffing cylinder, 18
...Boom, 20...Calculation unit, 21...Boom length detection means, 22...Wire hook number setting device, 23...
Boom angle detector, 24... Wire movement limit speed setter, 25.27... Multiplier, 26... Cosine generator, 2
8... Divider, 30... Hook position servo control system,
31... Hook height setter, 35... Winch motor, 36... Arithmetic unit. Figure 2 Figure 3

Claims (1)

[Claims] In an automatic horizontal movement device for a crane that horizontally moves a hoisted load by controlling the payout of a hoisting wire in response to the ups and downs of the boom, the boom length and the cosine value of the boom ups and downs angle are provided. and a calculation means for performing an operation with a value obtained by multiplying the number of wire windings as a divisor and a limit value of the wire moving speed as a dividend; and a limiter means for limiting the heave angular velocity given as a target value by the output of the calculation means. and a control means for controlling boom raising and lowering based on the output of the limiter means.