JPH04112195A - Suspended load setting controller for crane - Google Patents

Abstract

PURPOSE:To prevent a suspended load from being broken by installing a wind-down and jib turn up/down control means which carries out feed-forward control at a calcu lated aimed speed and a wind-down and jib turn-down correcting means which feedback-controls each variation quantity of the load and the top edge position to each certain value. CONSTITUTION:When a setting starting instruction means 21 is operated, the aimed time to for setting a suspended load is set. In order to reduce the suspended load T to zero through the lapse of the time to by an aimed wind-down speed calculating means 32, the proper aimed, wind-down speed of a winding-up rope is calculated and feed-forward controlled in correspondence with the vertical displacement quantity Z of the top edge of a jib. In order to reduce the horizontal displacement position H through the lapse of the aimed setting time to by an aimed jib turn-down speed calculating means 25, the aimed jib turn-down speed is calculated and feed-forward controlled. Since the tension and the jib top edge varies through the lapse of time by the feed-forward control, each driving device is correction-controlled by the feed- forward control so that the time differential value of each variation quantity becomes equal to each set value, and the suspended load is correctly set at a stable speed free from oscillation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hoisting load placement control device for hoisting and hoisting a hoisted load in the vertical direction in a crane having a jib or boom that can be raised and lowered. It is something.

[Conventional technology]

Conventionally, various devices (for example, Japanese Patent Publication No. 59-26599, Japanese Patent Application Laid-Open No. 61-211296) have been used as control devices for steadying the suspended load in cranes equipped with jibs or booms.
Publication No.) is known.

All of these conventional technologies are intended to prevent the suspended load from shifting forward and causing load swing when the suspended load is lifted off the ground by hoisting the hoisting rope. No consideration is given to subsequent control, especially control when a suspended load is placed in a predetermined location from a suspended state.

[Problem to be solved by the invention]

The work of placing suspended loads will be explained using FIG. 1 using a tower crane as an example. In FIG. 1, a jib 2 is supported at the upper end of a tower 1 so as to be able to rise and fall freely, and a hoisting rope 3 is suspended from the tip of the jib 2 via a top sheave or the like, and a suspended load 4 is supported. When the above-mentioned suspended load 4 is hoisted and grounded, and the suspended load 4 is moved to a predetermined location by hoisting and turning the hoisting rope 3, undulation of the jib 2, etc., and then left at that location, At the start of the suspension, that is, the suspended load 4
At the initial position at the moment of installation, the center of gravity of the suspended load 4 and the tip of the jib, that is, the top sheave, are on the same vertical line as shown by the solid line in Figure 1. The tower 1, jib 2, etc. are in a bent state due to the stretching of the hoisting rope 3 and the like. If the hoisting rope 3 is hoisted only by lowering it in such a state, the hanging load (rope tension) applied to the hoisting rope 3 will gradually decrease, the deflection of the jib etc. will also gradually become smaller, and the hoisting will be completed. In other words, when the suspended load 4 has completely landed on the ground, the hoisting rope 3 etc. are in an unloaded state, and the jib 2 etc. are no longer bent as shown by the broken line in FIG. Therefore, at the end of the stationary operation, the tip of the jib is displaced upward and rearward (toward the aircraft side) compared to when the stationary service begins. At this time, the amount of displacement in the horizontal direction of the tip of the jib is ΔH1, and the amount of displacement in the vertical direction is Δ2. These displacement amounts ΔH2ΔZ increase and decrease approximately in proportion to the magnitude of the suspended load.

As mentioned above, when a suspended load is placed in place, the hoisting rope and the tip of the jib move differently (almost in the opposite direction) than when cutting off the ground, which cannot be handled by conventional control devices for cutting off the ground. Therefore, in the past, operators used their own experience and intuition to
Alternatively, the sling can be manually operated by relying on signals from someone.
In reality, the lowering of the hoisting rope 3 and the lowering of the jib 2 are left in place while being slightly manipulated. In this case, the stationary operation is very difficult and the work efficiency is very low. In particular, if the hoisting rope 3 is lowered too quickly when the suspended load 4 is placed, a large impact will be applied to the suspended load 4, which may damage the suspended load 4.

In addition, if the lowering of the hoisting rope 3 and the tilting of the jib are not synchronized well, the tip of the jib will move from the initial position indicated by the solid line in Figure 1 to the no-load position indicated by the broken line in Figure 1 by an amount corresponding to the above displacement ΔH1Δ2. It quickly elastically returns rearward and upward, causing a so-called flip-up phenomenon.

Therefore, if the jib angle is set close to the maximum allowable angle at the beginning of the installation, there is a risk that the jib etc. will collide with the fall prevention stopper due to the flip-up phenomenon of the jib 2 at the end of the installation, which may damage the stopper. be.

In addition, if the hanging load 4 is a long object as shown in Figure 1, and is placed in the hole 5 with one end suspended and rolled up, the hanging load 4 will be suspended at the beginning of the installation. After the lower end touches the bottom of the hole, as the lifting progresses, the tip of the jib will be displaced backwards and upwards due to the elasticity of the jib, etc.
The bow is attached to the fuselage side) and may tilt in the hole 5, possibly breaking.

In view of these circumstances, the present invention has been devised so that a hoisting rope can be lowered and a jib can be lowered and placed in place without having to operate the hoisting rope and the jib by automatically adjusting them to each other with a simple operation. The present invention provides a suspended load placement control device that prevents breakage of a fall prevention stopper and the collapse and breakage of a suspended load, enhances safety, and significantly improves work efficiency.

[Means to solve the problem]

The present invention includes a jib that can be raised and lowered, a drive device for raising and lowering the jib,
A crane having a hoisting rope for a hoisting load and a drive device for hoisting and lowering the hoisting rope, the crane has a jib tip position detecting means, a hoisting load load detecting means, a hoisting load suspension start commanding means, and a hoisting rope. A deferred time setting means for setting a target deferred time from the start of deferred loading to the end of deferred loading; and deferred loading based on the detected load load at the start of deferred loading and the target deferred time. a lowering target speed calculating means for calculating a lowering target speed of the hoisting rope, and a lowering target speed calculating means for calculating a lowering target speed of the hoisting rope, and a hoisting rope for feedforward controlling the operation of the hoisting and lowering drive device based on the target speed calculated by the target speed calculating means. a lowering control means, a jib tilting target speed calculating means for calculating a jib tilting target speed based on a jib tip position detection value at the start of suspending the suspended load and the target hanging time; jib hoisting control means that feedforward controls the operation of the jib hoisting drive device based on the target speed set, and a jib hoisting control means that controls the operation of the jib hoisting drive device in a feedforward manner based on the target speed, and a jib hoisting control means that maintains a constant amount of change from moment to moment in the hoisted load based on the detected value of the hoisted load after the start of stationary work. a hoisting correction means for feedback controlling the operation of the hoisting and lowering drive device; The present invention is characterized by comprising a jib tilting correction means for feedback controlling the operation of the drive device.

[For production]

With the above configuration, by simply operating the suspension start command means, for example, turning on the switch, the lowering target speed calculated by the hoisting rope lowering target speed calculation means and the jib tilting calculated by the jib tilting target speed calculating means Based on the target speed, the lowering of the hoisting rope and the tilting of the jib are automatically operated in coordination with each other by feedforward control, so that the displacement of the jib tip due to deflection of the jib etc. becomes zero, that is, the jib The suspended load is automatically controlled so that the tip is always located vertically above the center of gravity of the suspended load, and
Furthermore, the hoisting rope is lowered and the jib is tilted so that the amount of momentary change in the load load and the momentary displacement of the tip of the jib are constant. is automatically corrected by feedback control. This allows the suspended load to be placed in the specified position accurately and smoothly, eliminating the risk of damage to the suspended load, damage to the fall prevention stopper, or falling or breaking of the suspended load, increasing safety and improving work efficiency. is greatly improved.

〔Example〕

FIG. 2 is a block diagram showing an embodiment of the control device according to the present invention. In Figure 2, 10 is a crane;
Corresponds to the tower crane shown in the figure.

This crane 10 is equipped with a tower height detector 11, a tower angle detector 12, a jib length detector 13, and a jib angle detector 14 as means for detecting the position of the tip of the jib, and a hoisting rope 3 as means for detecting the suspended load. A rope tension detector 15 such as a load cell is provided to detect the rope tension applied to the rope. Each of these detectors 11 to 15 is installed at a predetermined location on the crane 10, and generally, the detector of the overload prevention device that is already installed on the crane 10 is used as is.

Note that if the tower height Ht and the jib length 11 are stored in the microcomputer in advance, these stored values can be used as the detected values.

20 is a controller, 21 is a deferment start command means, 22
Reference numeral 40 indicates a stationary target time setting means, and 40 indicates a hydraulic system control means.

When performing crane work with the above tower crane, the suspended load 4
After being lifted off the ground by hoisting the hoisting rope 3 and undulating the jib 2, it is moved in a suspended state to a predetermined location by turning or the like, and is left in place under the following control. Note that a detailed explanation of the ground-off and turning control will be omitted here, and only the stationary control will be explained.

(2) Feedforward control First, the hoisting start command means 21 is turned on, and the target time for hoisting the hoisting load 4 is set, that is, when the hoisting load 4 touches the ground and the hoisting load ΔT (the tension applied to the hoisting rope 3) Target time t from when the amount of change (with respect to the no-load state) starts to decrease until the suspended load 4 completely lands on the ground and the suspended load load ΔT becomes substantially zero. Set. At this time, the suspension control may be automatically started by detecting the point in time when the suspended load 4 touches the ground and the suspended load load ΔT begins to decrease, and turning on the deferment start command means 21. In addition, the above target time to is manually set by the operator within a range in which lowering of the hoisting rope 3 and tilting of the jib 2 can be done without difficulty, and taking into consideration that it does not take too much time to set the hoist up. However, for example, if the characteristic curve of the load and moment of the crane is stored in advance in the input device 23 of the controller 20 or the storage unit attached to the overload prevention device, then - when the standstill start command means 21 is turned on; Then, the target suspension time t is determined based on the characteristic curve and the hanging load ΔT. may be calculated and automatically set.

Next, with respect to the hoisting rope 3, the hanging load ΔT is left in place for a target time t. Feedforward control of lowering is performed so that the lowering is carried out in a comfortable manner. At this time, it is predicted that as the hanging load ΔT decreases, the deflection of the jib 2 and the like will gradually become smaller, and the tip of the jib will be displaced rearward and upward. Therefore, jib 2
In contrast, the jib 2 is adjusted so that the predicted displacement of the jib tip is corrected so that the jib tip is located on the vertical line passing through the center of gravity of the suspended load 4.
The example feedforward control is performed.

For this control, each of the above-mentioned detectors 11 to 15 detects the tower angle θa, jib length ll, jib angle θ1, and suspended load ΔT.
are detected, and the detected values are sent to the controller 2.
0 input device 23. At the start of stationary work, the horizontal displacement amount calculation means 24 and the vertical displacement amount calculation means 31 of the jib tip calculate the horizontal displacement ΔH and vertical displacement based on the no-load state of the jib tip based on the initial values of the above-mentioned detection values. A quantity ΔZ is calculated. The horizontal displacement amount ΔH is the horizontal displacement amount ΔH1 caused by the angle change of the tower 1 and the jib 2.
It consists of the horizontal displacement amount ΔH2 caused by the angular change of
It is determined by the following formula.

ΔH=ΔH1+ΔH2 Electric HT (θa.-θ71) +1h(cotθ+a CQ5θ+1) ・=
(1) HA; Tower height θ 0: Tower angle at no load θ 0: Tower angle at the start of installation! , :Jib length θ10・Jib angle at no load θJ1. Jib angle at the start of deferment When calculating the above horizontal displacement amount ΔH, the tower angle θa and jib angle θ, 1 at the start of deferment are the same as when the suspended load 4 is suspended in the air before being deferred. Therefore, the horizontal displacement amount ΔH can be easily calculated by storing each angle detected during the suspension in advance in, for example, a storage unit of the overload prevention device. Also, the tower angle θa when no load is applied.

And the jib angle θ, 0 is the detected value θ17.0 at the initial position of the jib tip. Based on θ, 1 and the hanging load ΔT, it can be easily calculated using machine parameters, load-moment characteristic curves, etc. stored in the storage unit in advance. Alternatively, before the suspended load 4 is cut off the ground, the tower angle θTO and jib angle θ''0 at no load are detected in advance and stored in the storage section, and the leveling is determined by the above formula based on the stored values and the detected values. It is also possible to detect the amount of displacement ΔH.

Further, the vertical displacement amount ΔZ is obtained by the following equation.

ΔZ-11J (sinθ1O-sinθJ1)...
(2) Then, by the lowering target speed calculation means 32,
Target time t for leaving the suspended load ΔT. The optimum lowering target speed of the hoisting rope 3 is calculated in order to reduce the load to zero (no-load state). In this case, the jib tip is lowered by the vertical displacement amount of 62 due to the feedforward control of jib 2, and the hanging load ΔT decreases accordingly.
The target reduction amount [(ΔT-Δt)/lo] of the hanging load ΔT per unit time is calculated by considering the decrease Δt,
The lowering speed of the hoisting rope 3 corresponding to the target reduction amount is calculated as the target speed. This target speed is positive when the hoisting rope 3 is lowered and negative when it is hoisted up.

Next, the lowering feedforward control signal calculation means 33
By multiplying the target lowering speed by the feedforward gain KIL, a feedforward control signal EIL for lowering the suspended load 4 at the target speed is calculated. This control signal EIL is input to the electromagnetic proportional pressure reducing valve 42 of the hydraulic system control means 40 via the signal processing means 37. The electromagnetic proportional pressure reducing valve 42 outputs a hydraulic signal (pilot pressure) according to the control signal EIL. In response to the hydraulic signal, the control valve 44 for hoisting and lowering is switched to the lowering side, the spool stroke is controlled, and the hydraulic motor 46 of the drive device for hoisting and lowering is rotated at a target speed in the lowering direction. In this way, the hanging load Δ at the start of the stationary installation is
The hoisting rope 3 is lowered at a target speed according to the magnitude of T, the suspended load 4 is gradually lowered, the suspended load load ΔT gradually decreases, and the target time t is reached. Feedforward control is performed so that it becomes zero later.

On the other hand, for the jib 2, the jib tilting target speed calculating means 25 calculates a target reduction amount (Δ
H/z) is calculated, and the jib tilting target speed corresponding to the target reduction amount is calculated. The target speed is positive when the jib 2 is tilted, and negative when it is up and down.

Then, the jib tilting feedforward control signal calculation means 26 multiplies the jib tilting target speed by a feedforward gain KB, and calculates a feedforward control signal El for performing the example of jib 2 at the target speed. . This signal Ell is input to the electromagnetic proportional pressure reducing valve 41 of the hydraulic system control means 40 via the signal processing means 28. The electromagnetic proportional pressure reducing valve 41 outputs a hydraulic signal (pilot pressure) according to the control signal El. Based on the hydraulic signal, the jib hoisting control valve 43 is switched to the jib tilting side, and its spool stroke is controlled.
The hydraulic motor 45 of the jib hoisting drive device is rotated at a target speed in the jib tilting direction. In this way, in conjunction with the lowering of the hoisting rope 3, that is, the hanging load 4, the jib 2 is moved at a target speed according to the horizontal displacement ΔH (initial value) of the jib tip at the start of stationary work, and the jib tip Feedforward control is performed so that the vertical line is always located on the vertical line passing through the center of gravity of the suspended load 4.

Feedback control As the hoisting rope 3 is lowered by the feedforward control described above and the jib 2 is lowered, the tension applied to the hoisting rope 3 changes from moment to moment, and the jib hoisting rope stretches and the tower 1 and the deflection of jib 2 gradually decreases,
The tip of jib 2 changes from moment to moment. Therefore, in order to always keep the amount of change and displacement constant, the following feedback control is performed.

First, the momentary suspended load ΔT detected by the suspended load detector 15 is input to the time differentiator 34 and differentiated by time t (dΔT/d t). Then, the deferment end determining means 35 determines whether the time differential value (dΔT/dt) is constant (set range) or not. Time derivative (d
If ΔT/dt) exceeds the set range, the determining means 35 instructs the feedback control signal calculating means 36 to perform feedback control of lowering. Based on this command, the calculation means 36 calculates the momentary time differential value (dΔT
/dt), the time differential value (dΔT/dt
) is defined as the deviation ΔΔT, and the deviation Δ
Proportional and integral gain KPL+ to make ΔT zero
A feedback correction signal EEL for lowering the hoisting rope 3 is calculated by multiplying by KIL, and the correction signal EBL
is input to the signal processing means 33. Therefore, the signal processing means 37 receives the feedforward control signal E +
L and the feedback correction signal Ell are input, and a control signal (E IL + E BL) calculated from both signals is input to the electromagnetic proportional pressure reducing valve 42.

Therefore, a hydraulic signal corresponding to the control signal is output from the electromagnetic proportional pressure reducing valve 42, and the spool stroke of the hoisting/lowering control valve 44 is corrected and controlled by the hydraulic signal, and the hydraulic motor 46 of the hoisting/lowering drive device is controlled. The amount of rotation is corrected and controlled. Then, the time differential value (dΔT/dt) of the momentary suspended load ΔT of the hoisting rope 3 caused by the feedforward control becomes the grounding target value, that is, the amount of change (decrease) in the suspended load ΔT. ) is always constant, the lowering of the hoisting rope 3 is feedback-controlled. As a result, the suspended load 4 is placed smoothly at a stable speed without being subjected to impact.

Note that when the time differential value (dΔT/, dt) is within the set range, it is determined that the feedforward control is being performed properly, and the signal processing means 37.28, the command was given to perform only feedforward control of lowering and tilting the jib.

On the other hand, the current horizontal displacement amount ΔH of the jib tip, which is successively calculated by the jib tip horizontal displacement amount calculation means 24, is input to the feedback correction signal calculation means 27. Here, the target reduction amount (ΔH/lo) of the horizontal displacement amount ΔH of the jib tip,
Deviation ΔΔ between the momentary horizontal displacement amount ΔH and the actual decrease amount
H is determined, and a feedback correction signal E□ is calculated by multiplying the proportional and integral gains to zero the deviation ΔΔH by , and the signal E@ is sent to the signal processing means 28. is input. In this case as well, the signal processing means 28
The feedforward control signal E++ and the feedback correction signal EllJ described above are inputted to the controller, and a control signal (E IJ+ E @I) calculated from both signals is inputted to the electromagnetic proportional pressure reducing valve 41 . And the electromagnetic proportional pressure reducing valve 4
1 outputs a hydraulic signal according to the control signal, the hydraulic signal controls the spool stroke (opening area) of the jib hoisting control valve 43, and the rotation amount of the hydraulic motor 45 of the jib hoisting drive device is corrected and controlled. be done.

As a result, the tilting of the jib 2 is feedback-controlled so that the amount of decrease in the moment-to-moment horizontal displacement ΔH of the tip of the jib 2 caused by the feedforward control is always constant, and the tip of the jib 2 is always kept in line with the suspended load 4. The suspended load 4 is accurately controlled so that it is positioned on the vertical line passing through the center of gravity.
will be deferred. Therefore, the hanging load 4 is accurately placed vertically at a predetermined location without being pulled toward the machine body, swinging, or falling over.

When the suspension of the suspended load 4 is completed, the suspended load ΔT becomes substantially zero, and the time differential value of the suspended load ΔT (dΔT/dt)
also becomes zero. Then, it is determined by the deferment completion determination means 35 that the suspension of the hanging load 4 has been completed, and this determination means 35
from the automatic stop command means 38 to the signal processing means 28.3.
A stationary control stop command signal is output to 7, and the electromagnetic proportional pressure reducing valve 41, 42 is activated by the signal from the signal processing means 28.
The hydraulic signal output from the hydraulic motor 45 becomes zero, each control valve 43, 44 is returned to the neutral position,
．． 46 is stopped, the lowering of the suspended load 4, that is, the hoisting rope 3, and the tilting of the jib 2 are stopped, and the control of the suspension is completed.

Note that during the above control, if the jib angle θ,1 at the start of stationary work is small, the vertical displacement amount Δ2 of the jib tip is larger than the horizontal displacement amount ΔH, and the jib angle θ, Conversely, when l is large, the horizontal displacement ΔH of the jib tip becomes larger than the vertical displacement Δ2.

Therefore, during stationary control, the hoisting rope 3 may
It may also be used to hoist the jib or raise the jib.

Furthermore, during the above control, if the manual stop command means 47 such as a control lever of a remote control valve is operated, each of the above controls is immediately canceled, and each electromagnetic proportional pressure reducing valve is 41 and 42 are operated, the control valves 43 and 44 are returned to their neutral positions, and the motors 45 and 46 are stopped or operated in the danger avoidance direction, thereby ensuring safety.

In the above embodiment, the case where the lowering of the hoisting rope 3 and the tilting of the jib 2 are controlled by flow rate control is explained, but when the lowering of the hoisting rope 3 is controlled by pressure using an electromagnetic proportional relief valve etc. This can also be done in the same manner as above.

It goes without saying that the device of the present invention can be applied not only to the tower crane of the above embodiment, but also to ordinary jib cranes, rough terrain cranes with telescoping booms, and the like.

〔Effect of the invention〕

As described above, the present invention uses feedforward-based control based on a start-of-stay command to unwind a hoisting rope and a jib without interlocking each other, and then suspends a suspended load. The control results are tracked and feedback control is used to control the amount of change in the suspended load and the amount of displacement at the tip of the jib to be constant. There is no need to perform any operations, and the suspended load can be automatically placed in the vertical direction. Moreover, when the hoisting starts, a large shock is not applied to the hoisted load, and damage to the hoisted load can be reliably prevented and the hoisting can be done smoothly.Furthermore, the tip of the jib is always aligned vertically through the center of gravity of the hoisted load. It is possible to accurately place the jib while correcting the position so that it is on the line, prevents the so-called flipping phenomenon of the jib, prevents damage to the overload prevention stop and buckle, and prevents the suspended load from falling over. Breakage can be reliably prevented and safety can be improved.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an example of stationary work using a tower crane, and FIG. 2 is a block diagram showing an embodiment of the present invention. 1... Tower 2... Jib, 3... Hoisting rope,
4... Hanging load, 10... Tower crane, 11...
Tower height detector, 12... Tower angle detector, 13
...Jib length detector, 14...Jib angle detector, 1
5... Hanging load detector, 20... Controller (control means), 21... Stationary control start command means, 22.
...Target time setting means, 23...Input device, 24...
・Horizontal displacement amount calculation means for the tip of the jib, 25... Jib tilting target speed calculation means, 26... Jib tilting feed forward control signal calculating means, 27... Jib tilting feedback control signal calculating means, 28... signal processing means, 31
... Vertical displacement amount calculation means of the jib tip, 32 ... Lowering target speed calculation means, 33 ... Lowering feed forward control signal calculation means, 34 ... Time differentiator, 35.
... Deferred completion determination means, 36... Lowering feedback control signal calculation means, 37. Signal processing means, 38.
... Automatic stop command means, 40 ... Hydraulic system control means,
4142... Solenoid proportional pressure reducing valve, 43.44... Control valve, 45.46... Hydraulic motor, 47.
...Manual stop command means. Patent applicant: Kobe Steel, Ltd. Agent
Patent Attorney Etsushi Kotani Patent Attorney Chief 1
) Masaru Patent Attorney Takao Ito

Claims (1)

[Scope of Claims] 1. Detection of the jib tip position in a crane having a jib that can be hoisted freely, a drive device for hoisting the jib, a hoisting rope for hoisting a load, and a drive device for hoisting and lowering the hoisting rope. means for detecting a suspended load; means for commanding the start of suspension of a suspended load; a suspension time setting means for setting a target suspension time from the start of suspension of the suspended load to the end of suspension; a lowering target speed calculation means for calculating a lowering target speed of a hoisting rope for suspending a suspended load based on the detected load load at the start and the target suspension time; a lowering control means that performs feedforward control of the operation of the hoisting and lowering drive device based on the set target speed; jib hoisting control means for feedforward controlling the operation of the jib hoisting drive device based on the target speed calculated by the jib hoisting target speed calculation means; A lowering correction means for feedback controlling the operation of the hoisting and lowering drive device so that the amount of change from moment to moment in the suspended load is constant based on the detected value of the load load, and detecting the jib tip position after the start of hoisting. and a jib tilt correction means for feedback controlling the operation of a jib hoisting drive device so that the amount of change from moment to moment in the jib tip position is constant based on the value. Device.