JPH03284599A - Perpendicular off-ground control device of hanging load on crane - Google Patents

Abstract

PURPOSE:To surely prevent load deflection so as to smoothly perform off-ground operation by providing a control means, which drive-controls jib-elevating and hoist rope up/down-winding driving gears in accordance with a control signal output from each arithmetic means, to improve control accuracy of the off- ground operation. CONSTITUTION:Target values of a rise speed of a jib 2 and a rewinding or delivery speed of a hoist rope 3 are determined in accordance with the initial position of a point end of the jib 2 especially its initial angle THETAJO, and a rise of the jib 2 and up or down winding of the hoist rope 3 are performed associated with each other by control, mainly composed of feedforward operation, with these target values serving as the reference. Further a result of the control is traced, and up or down winding amount of the hoist rope 3 is controlled by feedback control, so as to obtain fixed tension of the hoist rope 3, while performing position control of the point end of the jib 2 by feedback control so that a horizontal displacement amount H of the point end of the jib 2, according to increase of tension of the hoist rope 3, is always zero.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a crane having a jib or boom that can be hoisted and hoisted in a vertical direction to prevent load swing when hoisting a hoisted load in the vertical direction and cutting it off the ground. The present invention relates to a ground cutting control device.

[Conventional technology]

When hoisting a suspended load using a crane equipped with a jib or boom, even if the tip of the jib, etc. is aligned with the vertical line passing through the center of gravity of the suspended load at the start of hoisting, the jib will The tip of the jib etc. shifts forward from the above-mentioned vertical line due to the deflection of the jib etc. If you hoist only the hoisting rope while the tip of the jib etc. remains shifted forward in this way, the moment the hoisted load leaves the ground (at the time of breaking off the ground), the hoisted load will move forward, causing load swing. .

Conventionally, as shown in Japanese Patent Publication No. 59-26599, a device for preventing such load swinging during ground cutting has been used in a crane with a jib to control the speed command value output from the hoisting speed command device and the hoisting speed command value output from the hoisting speed command device. The hoisting starting torque command device outputs a starting torque command signal that rises in steps and changes over time in accordance with the deviation from the speed detection value of the electric motor for use.Based on this command, the hoisting speed of the suspended load is feedback-controlled. , instructing the amount of deflection of the jib from a deflection amount indicating device according to the moment of the jib, and outputting a hoisting speed from the jib hoisting amount instruction device based on the deflection amount and the hoisting speed command signal; The jib raising speed is feedback-controlled according to the deviation between the speed command and the detected rotational speed value of the electric motor for jib raising,
It is known that an attempt is made to compensate for the forward displacement of the tip of the jib by raising the jib.

As another method, as shown in Japanese Patent Application Laid-open No. 191393/1983, in order to position the tip of the boom vertically above the suspended load by raising and lowering the boom alone, the boom length l and , the cosine value of the boom hoisting angle θ and the boom hoisting angular velocity θ, the vertical movement speed of the boom tip caused by the boom hoisting operation V (υ=l−cohθ
・θ) is calculated, this speed V is set as the moving speed command value of the hoisting rope, and the detected value of the moving speed of the hoisting rope is
It is known that the moving speed of the hoisting rope is controlled by a servo control device so that the deviation from the command value becomes zero.

[Problem to be solved by the invention]

The conventional device disclosed in Japanese Patent Publication No. 59-26599 has the following problems.

■ Since the drive torque command for hoisting a suspended load is increased step by step, the hoisting speed of the suspended load changes greatly when the steps change, and transient vibrations are likely to occur.
In addition, it takes more time to finish cutting off the ground than when the hoisting speed of the suspended load is continuously increased.

◎ In order to minimize load swing during ground cutting, it is necessary to always position the jib tip vertically directly above the hoisting hook, and to do so, it is necessary to control the position of the jib tip. With this conventional device, the retraction speed of the jib is controlled in accordance with the hoisting speed of the hoisted load, but with such speed control alone, the position of the jib tip cannot be accurately controlled, and the jib tip is moved at the moment of breaking off the ground. There is no guarantee that the load is directly above the suspended load, and it is difficult to reliably prevent load swing.

θ The amount of deflection at the tip of the jib is determined according to the moment of the jib, and the raising speed of the jib is controlled based on this amount of deflection, but the amount of deflection cannot be determined by the moment alone. In other words, the amount of deflection differs even with the same moment depending on the initial jib angle, jib length, etc. Accurate control cannot be achieved even if control is performed using an uncertain deflection amount as a reference.

■ In other words, when the initial angle of the jib is small, when the jib is raised, the vertical displacement of the tip of the jib is larger than the horizontal displacement, so the tension on the hoisting rope increases rapidly. The suspended load is cut off before the forward horizontal displacement of the jib tip can be corrected. In such cases, it is necessary to raise the jib while lowering the rope to keep the increase in rope tension within a certain limit, but with this conventional device, the control is based on the hoisting of the hoisting rope. Therefore, such lowering control cannot be performed.

On the other hand, in the conventional device shown in JP-A No. 62-191393, the moving speed of the hoisting rope is controlled to keep the tension of the rope constant in order to correct the position of the boom tip that shifts due to the raising and lowering operation of the boom. However, it is difficult to accurately control the position of the boom tip just by controlling the moving speed of the hoisting rope in this way.
If the tip of the boom remains deviated from the vertical line passing through the center of gravity of the suspended load, there is a risk that the suspended load will fall off the ground, and it is difficult to reliably prevent the load from swinging.

The present invention solves the above-mentioned conventional problems, and no matter how the tip of the jib, etc. changes from the initial position by the ground cutting start command, it automatically and continuously uses control suitable for the initial position. Through the operation, the tip of the jib etc. can be accurately corrected to the initial position and the suspended load can be taken off the ground, improving the control accuracy of the ground cutting, reliably preventing the load from swinging, and making it possible to take the suspended load off the ground smoothly. The purpose is to obtain a vertical ground cutting control device.

[Means to solve the problem]

In order to achieve the above object, the apparatus of the present invention is configured as follows.

■ In a crane that has a jib that can be hoisted freely, a drive device for jib hoisting, a hoisting rope for a hoisting load, and a drive device for hoisting and lowering a hoisting rope, a means for detecting the jib tip position and a device for detecting the hoisting load The detection means, the ground cutting control start command means, and the target value of the jib raising speed and the hoisting rope winding based on the initial value of the jib tip position detected by the jib tip position detection means by inputting the ground cutting control start command signal. a target value calculation means for calculating a target value of the raising/lowering speed; a first calculation means for outputting a feedforward control signal for raising the jib based on the target value of the jib raising speed calculated by the target value calculating means; a second calculation means for outputting a feedforward control signal for hoisting rope hoisting and lowering based on the hoisting rope hoisting and lowering speed target value calculated by the target value calculation means; a third calculation means that calculates the amount of displacement of the jib tip position based on the amount of displacement, uses the amount of displacement as a deviation, and outputs a jib raising feedback control signal for controlling the position of the jib tip so that the deviation becomes zero;
The amount of change in the suspended load per unit time is calculated based on the detected value by the above-mentioned suspended load load detection means, and the hoisting rope is hoisted and lowered so that the deviation between the amount of change and the set value is zero. a fourth calculation means for outputting a foot knock control signal; and a control means for driving and controlling a jib hoisting drive device and a hoisting rope hoisting and lowering drive device according to the control signals output from the respective calculation means. It is equipped with

■ In the above configuration (■), the jib tip position detection means has a jib angle detector, and the target value calculation means detects when the initial value of the jib angle detected by the jib angle detector is larger than the set value. Calculate the target hoisting speed for hoisting the hoisting rope at a speed corresponding to the initial value of the jib angle, and if it is less than the set value, the lowering speed for hoisting the hoisting rope at a speed corresponding to the initial value of the jib angle. It is configured to calculate a target value.

(2) In the above configuration (2) or (2), signal processing means is provided for regulating the maximum value and minimum value of each feedforward control signal output from the first and second calculation means.

■ In any of the above configurations ■ to ■, the rise pattern of each feedforward control signal output from the first and second calculation means is changed from the reference value (zero) to the target control value within the set time. It is equipped with signal processing means for increasing the signal gradually.

■ In any of the above configurations ■ to ■, there is a differentiator that time-differentiates the amount of change in the suspended load detected by the suspended load detection means, and the time differential value is within the set range for the set time. and a control stop command means for outputting a control stop signal to each of the drive devices based on a termination signal from the determining means. ing.

■ In any of the above configurations ■ to ■, a signal processing means for gradually decreasing the control signal for each of the drive devices from the control value to the reference value (zero) within a set time based on the control stop signal from the control stop command means. It is equipped with

■ In any of the above configurations (■ to ■), the jib is supported at the upper end of the tower so that it can rise and fall freely, and the means for detecting the jib tip position is determined from the tower height, tower angle, jib length, and jib angle detectors. The jib tip position is determined based on the values detected by each of these detectors.

■ In the above configuration (■), the jib hoisting drive device has a hydraulic motor that drives the jib hoisting rope winding drum, and the hoisting rope hoisting and lowering drive device drives the hoisting rope winding drum. It has a hydraulic motor, and the control signal outputs a control valve that controls the inflow flow rate of pressure oil from the hydraulic source to each of the hydraulic motors, and outputs a hydraulic signal for switching control of each control valve in accordance with each of the control signals. Equipped with an electromagnetic proportional pressure reducing valve.

■ In any of the above configurations ■ to ■, the jib is a boom supported on the upper revolving structure of the crane so that it can be raised and lowered, and the means for detecting the jib tip position is a boom length detector and a boom angle detector. The boom tip position is determined from the boom length and boom angle detected by each of the detectors.

0 In the above configuration (3), the jib hoisting drive device has a hydraulic cylinder for boom hoisting, and the hoisting rope hoisting and lowering drive device has a hydraulic motor that drives the winding drum of the hoisting rope, and It includes a control valve that controls the flow rate of pressure oil into the hydraulic cylinder and the hydraulic motor, and an electromagnetic proportional pressure reducing valve that outputs a hydraulic signal for switching control of each control valve in accordance with each of the control signals.

[For production]

With the above configuration, after setting the tip of the jib (or boom) to the initial position on the vertical line passing through the center of gravity of the suspended load, if you operate the ground cutting control start command means, the jib (or boom) The initial position of the tip is detected, the target value of the jib raising speed and the hoisting rope hoisting or lowering speed target value are calculated according to the initial position, and the jib is raised by feedforward control based on these target values. The hoisting rope is hoisted or lowered smoothly, and in parallel with this feedforward control, the jib tip quickly returns to its initial position by feedback control while tracking the actual position change of the jib tip. The position is precisely controlled so that it returns.

Furthermore, in parallel with this position control of the jib tip, feedback control is carried out so that the amount of increase in the suspended load is constant while the suspended load is pressure-tested. In this way, feedforward control and feedback control that uses the results as deviations are performed for both raising the jib and hoisting or lowering the hoisting rope, thereby controlling the position of the boom tip and increasing the lifting load. By linking a large number of controls to each other, the control accuracy of ground cutting can be improved, regardless of the initial position of the jib tip (large or small initial angle), or even if the size of the hanging load is unknown. The suspended load is automatically and continuously cut off to the ground in the vertical direction, reliably preventing load swing.

〔Example〕

FIG. 2 is a conceptual diagram of a tower crane to which the present invention is applied. In FIG. 2, 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 hanging from the tip of the jib 2 supports a suspended load 4.

When vertically cutting the suspended load 4, the tip of the jib 2 (top sheave), the hook at the end of the hoisting rope 3, and the center of gravity of the suspended load 4 are on the same vertical line, as shown by the solid line in the figure. (initial position).

If the hoisting load 4 is hoisted from the initial position shown by the solid line in FIG. The rope is stretched, the tower 1 and the jib 2 are deflected, and the tip of the jib 2 is displaced forward and downward as shown by the broken line in FIG. Furthermore, when the jib 2 is raised in order to make this forward horizontal displacement amount ΔH zero, the tip of the jib 2 is pulled in horizontally and at the same time is also pulled vertically upward. In this case, in particular, the initial angle θ of the jib 2. is small, the vertically upward displacement ΔZ is larger than the horizontal displacement ΔH of the jib tip caused by raising the jib 2, and the tension of the hoisting rope 3 increases rapidly, causing the above horizontal displacement. There is a risk that ground cutting will occur before ΔH is corrected, causing load swing. Also, conversely, the initial angle θ of the jib 2. When is large, the vertically upward displacement ΔZ is smaller than the horizontal displacement ΔH of the jib tip caused by raising the jib 2, so the rate of increase in the tension of the hoisting rope 3 is small. The time required to cut the ground will be longer.

The present invention prevents such load swing and efficiently moves the suspended load 4.
The following control device is used to perform vertical ground cutting.

FIG. 1 is a block diagram showing an embodiment of a control device according to the present invention. This control device includes a tower height detector 11 and a tower angle detector 12 as means for detecting the jib tip position.
, a jib length detector 13, and a jib angle detector 14. Reference numeral 15 denotes a hanging load load detector, which is usually a load meter or the like that detects the tension applied to the hoisting rope 3 as the hanging load load. Each of these detectors 11 to 15 is installed at a predetermined location on the crane 10, and a detector of an overload prevention device that is generally installed on the crane 10 can be used. Further, if the tower height Hr and the jib length IJ are stored in the microcomputer in advance, these storage devices can be used as the setting device.

Note that 20 is a controller, 21 is a ground cutting control start command switch, and 40 is a hydraulic system control means.

Next, vertical ground cutting control of a suspended load will be explained.

(2) Feedforward control The above detectors 11 to 14 determine the tower height Hf, tower angle θa, and jib length shown in FIG. 2! 1. The jib angle θ1 is detected, and these detected values are input to the input device 22. Here, when the ground cutting control start switch 21 is turned on, the signal is input to the input device 22 of the controller 20, and at the same time, the initial values HT and θa of the detected values are set. , I
5. θ,.

is input to the target value calculation means 23 via this input device 22.

The target value command means 23 determines the initial position of the tip of the jib 2, that is, each of the above initial values HT, θTO+' 1 r θ,
0, the optimal value of the raising speed of the jib 2 (see Figure 3) and the optimal value of the hoisting and lowering speed of the hoisting rope 3 in order to ensure that the vertical ground cutting of the suspended load 4 is performed smoothly. value (4th
(see figure) is calculated as the target value. In this case, jib 2
When the initial angle θ10 of the jib 2 is larger than the set value, the target hoisting speed for hoisting the hoisting rope 3 is calculated as shown by solid line A in Figure 4. However, when the initial angle θ,0 of the jib 2 is less than the set value calculates the lowering speed target value for lowering the hoisting rope 3 as indicated by the solid line in the figure. Note that the target value of the raising speed of the jib 2 is set to an optimum speed within a range where follow-up control of hoisting and lowering of the hoisting rope 3 can be performed smoothly.

Next, based on the jib raising speed target value calculated by the target value calculation means 23, the first calculation means 24 generates a feedforward control signal (E
A)+. is calculated, and the control signal is sent to the signal processing means 32
The signal is then output to the electromagnetic proportional pressure reducing valve 41 of the control means 40 of the hydraulic system. The electromagnetic proportional pressure reducing valve 41 is connected to the signal processing means 32.
The spool stroke of the jib hoisting control valve 43 is controlled by the hydraulic signal (pilot pressure), and the inflow flow from the hydraulic source to the hydraulic motor 45 of the jib hoisting drive device is controlled. The rotational speed of the motor 45 is controlled. As a result, the jib 2 is raised at an optimal target speed according to the initial position of the jib tip.

On the other hand, in parallel with raising the jib 2, a gain KF
A feedforward control signal (EA) LO multiplied by L is calculated, and the control signal is outputted to the electromagnetic proportional pressure reducing valve 42 via the signal processing means 33. The electromagnetic proportional pressure reducing valve 42 receives a hydraulic pressure signal (
The spool stroke of the hoisting rope hoisting/lowering control valve 44 is controlled by the hydraulic signal, and the inflow flow from the hydraulic source to the hydraulic motor 46 of the hoisting rope hoisting/lowering drive device is controlled. , the rotational speed of the motor 46 is controlled. As a result, the hoisting rope 3 is hoisted or lowered at an optimal target speed corresponding to the initial position of the jib tip.

In this case, especially the initial position of the jib 2, that is, the initial angle θ
,. is less than the set value, the vertically upward displacement amount is larger than the horizontal displacement amount of the jib tip caused by raising the jib 2, but as described above, the target value calculation means 2
Since the hoisting rope 3 is lowered based on the lowering speed target value of the hoisting port 3 calculated in step 2, a sudden increase in the tension of the hoisting rope 3 is prevented. There is no possibility that the suspended load 4 will be cut off before the horizontal displacement amount ΔH of the jib tip is corrected. Furthermore, when the initial angle θ, 0 of the jib 2 is larger than the set value, the amount of vertical displacement of the tip of the jib caused by raising the jib 2 in the horizontal direction is smaller than the amount of displacement in the horizontal direction, but as described above, Since the hoisting rope 3 is lowered based on the hoisting speed target value of the hoisting rope 3 calculated by the target value calculating means 22,
This prevents the rate of increase in the tension of the hoisting rope 3 from becoming small.

■ Feedback control Raising the jib 2 using the feedforward control described above,
As the hoisting rope 3 is hoisted or lowered, elongation of the jib hoisting rope and deflection of the tower 1 and jib 2 occur, and the tip position of the jib 2, that is, the tower angle θA and the jib angle θ, change from moment to moment. At the same time, the hoisting rope 3
The tension applied to it also changes from moment to moment. Therefore, in order to reduce the amount of change to zero, the following feedback control is performed.

In other words, the tower angle θ and jib angle θ change from moment to moment, and the predetermined tower height H and jib length! , are detected by the detectors 11 to 14, respectively, and these detected values are sequentially input to the displacement calculation means 26, where the actual horizontal displacement ΔH of the jib tip position is calculated based on each of the detected values. Ru. The horizontal displacement amount ΔH of the tip of the jib 2 is composed of the horizontal displacement amount ΔH1 caused by the angular change of the tower 1 and the horizontal displacement amount ΔH2 caused by the angular change of the jib 2, and is determined by the following equation (1).

ΔH=ΔH1+ΔH2 ==E(T(tinθto−tinθTo)+71(co
sθl −Co(θ10) (1) HT: Tower height! , : jib length θT. = Tower initial angle 0: Tower angle θ, o: Jib initial angle θ, : Jib angle ΔH assumes that forward displacement is “positive”.

The horizontal displacement amount ΔH of the jib tip calculated by the displacement amount calculation means 26 is inputted to the third calculation unit 27, where the momentary horizontal displacement amount ΔH is defined as a deviation, and the deviation ΔH is input to the third calculation unit 27.
Proportional and integral gain K PI+ to make H zero
A feedback control signal (EA) III corresponding to the required raising amount of the jib 2 multiplied by K I4 is calculated, and the control signal is input to the signal processing means 32. Therefore,
The signal processing means 32 receives the aforementioned feedforward control signal (EA) 1. and feedback control signal (EA)
+++ is input, and a control signal calculated from both signals is input to the electromagnetic proportional pressure reducing valve 41. Then, a hydraulic signal corresponding to the control signal is output from the electromagnetic proportional pressure reducing valve 41, and the jib hoisting control valve 4
The spool stroke (opening area) of No. 3 is controlled, the inflow flow rate to the hydraulic motor of the jib hoisting drive device is controlled, and the amount of rotation of the motor is controlled. As a result, the jib 2 is adjusted so that the momentary horizontal displacement amount ΔH of the tip of the jib 2 caused by the feedforward control is always zero.
The amount of raising of the jib 2 is feedback-controlled, and the position of the jib 2 is accurately controlled so that the tip of the jib 2 is returned to its initial position.

On the other hand, during this control, the tension applied to the hoisting rope 3 is sequentially detected by a suspended load load detector 15 such as a load meter. This detected value changes from moment to moment until the end of the ground cutting, and when the ground cutting is finished, it stops changing and becomes a value corresponding to the hanging load, that is, a constant value. Therefore, even if the hanging load is not known, it can be determined that the ground breaking has been completed when the tension of the hoisting rope 3 is constant, that is, the amount of change ΔT in the rope tension becomes the set value (zero) and the set time elapses.

Therefore, in order to determine whether or not the ground cutting has been completed, the tension of the hoisting rope 3 detected by the above-mentioned hanging load load detector 15 is input to the time differentiator 29, and the above-mentioned rope tension is determined by this time differentiator 29. The momentary change amount ΔT is differentiated with respect to time t (dΔT/dt), and the change amount per unit time of the rope tension is determined. Then, its time differential value (dΔT/
dt) is input to the ground cutting completion determining means 29, and it is determined whether the time differential value (dΔT/dt) is at the ground cutting target value determined by the ground cutting target time.

When the above-mentioned time differential value (dΔT/dt) is other than the ground-cutting target value, it is determined that the ground-cutting has not been completed, and the fourth calculation means 30 calculates the above-mentioned time differential value (dΔT/dt) and the ground-cutting target value. The deviation ΔΔT from EA)BL is input to the signal processing means 33. In this case as well, the signal processing means 33 receives the feedforward control signal (EA
) IL and a feedback control signal (EA) IIL are input, and a control signal calculated from both signals is input to the electromagnetic proportional pressure reducing valve 42. Then, a hydraulic signal corresponding to the control signal is outputted from the electromagnetic proportional pressure reducing valve 42, and the spool stroke (opening area) of the control valve 44 for hoisting and lowering the hoisting rope is controlled by the hydraulic signal. The inflow flow rate to the hydraulic motor 46 of the vertical drive device is controlled, and the amount of rotation of the motor 46 is controlled.

As a result, the time differential value (dΔT/dt) of the momentary displacement position ΔT of the tension applied to the hoisting rope 3 caused by the feedforward control is set to the ground breaking target value, that is, the rope tension is kept constant. , the amount of hoisting and lowering of the hoisting rope 3 is feedback-controlled.

As mentioned above, the target values for the raising speed of the jib 2 and the winding or unwinding speed of the hoisting rope 3 are determined according to the initial position of the tip of the jib 2, especially the initial angle θ, 0 of the jib 2, and The raising of the jib 2 and the hoisting or lowering of the hoisting rope 3 are performed in conjunction with each other using feedforward-based control based on the target value, and the results of the control are tracked and the hoisting rope 3 is The position of the tip of the jib 2 is controlled by feedback control so that the horizontal displacement amount ΔH of the tip of the jib 2 due to an increase in the tension of the hoisting rope 3 is always zero, and the tension of the hoisting rope 3 is kept constant. By controlling the amount of hoisting or lowering of the hoisting rope 3 using feedback control, the tip of the jib is quickly and accurately returned to the initial position, and then the suspended load is grounded in the vertical direction, and the transient There is no vibration or load swing, and the load is cut smoothly.

Note that when the ground cutting is completed, the tension of the hoisting rope 3 becomes constant (same as the hoisting load), and the amount of change in rope tension ΔT
The time differential value (dΔT/dt) reaches the ground-off target value. Then, the ground cutting completion determination means 29 determines that the ground cutting has ended, and the determination means 29 outputs a ground cutting control stop command signal to the signal processing means 32, 33 via the automatic stop command means 34, and this signal processing The signal from the means 32.33 causes the hydraulic signal of the electromagnetic proportional pressure reducing valve 34.35 to become zero, each control valve 43.44 is returned to its neutral position, each hydraulic motor 45, 46 is stopped, and the control of the ground cutting is stopped. be terminated.

(2) Others In the above control, at the start of ground cutting, the jib 2 is first raised by feedforward control and the hoisting rope 3 is hoisted or lowered, so to prevent them from operating suddenly. 1st. Second calculation means 24.
Each feedforward control signal (EA) for raising the jib and raising and lowering the hoisting rope output from 25,
(EA)to becomes a control value at a predetermined start-up time t, 1 (for example, about 2 to 3 seconds) according to the start-up pattern shown in FIGS. 3 and 4 by the signal processing means 32 and 33. It is desirable to perform signal processing to gradually increase the amount.

This prevents a sudden shock from occurring in the shib 2, etc. at the start of the ground cutting control, and the ground cutting control is started smoothly.

Further, the signal processing means 32.33 have feedforward control signals (EA) ro, (EA) L, ll,
Since the feedback control signals (EA) a+ and (EA) aL are input, the electromagnetic proportional pressure reducing valve 4 is controlled based on these signals.
Control Signal (EA) for 1.42 J.

(EA)L is calculated. In this case, there is a dead zone in the hydraulic system, that is, a time lag between when the hydraulic signal is output from the electromagnetic proportional pressure reducing valve 41.42 and when the control valves 43 and 44 are opened and oil flows into the hydraulic motor 45.46. Therefore, in order to correct this dead zone, the control signals (EA)r and (EA)L calculated from the feedforward control and feedback control signals are predetermined by the signal processing means 32 and 33 as shown in FIG. Offset processing for nonlinear compensation is performed using the offset value of , and the control signals (EE)r and (EE)L after nonlinear compensation are output.

FIG. 6 shows the control signals (EE)J, (EE)L output from the signal processing means 32.33 and the electromagnetic proportional pressure reducing valve 41.
Hydraulic signal (pilot pressure) PfJ output from 42,
It is a figure showing the relationship with PzL. FIG. 7 is a diagram showing the relationship between the pilot pressure P'l+P'L and the inflow flow rates Q□, QL to the hydraulic motor 45 for driving the raising drum of the jib 2 and the hydraulic motor 46 for driving the winch drum.

The inflow flow rates Q+ and Q- determine the raising speed and amount of the jib 2, and the hoisting (lowering) speed and hoisting (lowering) amount of the hoisting rope 3.

In the above control, the first and second calculating means 2
The maximum and minimum values of the feedforward control signals for raising the jib 2 and hoisting and lowering the hoisting rope 3 inputted from 4.25 are regulated by the signal processing means 32 and 33, and these control signals are controlled. It is desirable to limit the signal to an optimal range.

Furthermore, when the control of ground shearing is completed, when the determination means 29 determines that the ground shearing has been completed, the speed of raising the jib 2 and hoisting and lowering the hoisting rope 3 at that point is adjusted for a certain period of time t1, ( For example, the feedforward control signal (EA) to,
(EA) A stop pattern in which the LO is gradually decreased as shown in FIGS. 3 and 4 is set in the stop command means 31, and the electromagnetic proportional pressure reducing valve 32
．． It is desirable to gradually stop the hydraulic motors 44 and 45 by controlling the hydraulic motors 33 and the like. During this time, the feedback control for the jib 2 continues, and the feedback control for the hoisting rope 3 is stopped. By doing this, there is no risk that the jib 2 will be raised too much due to inertia, load vibration, etc. or the suspended load 4 will bounce against the ground at the end of the ground cutting, and the ground cutting will be completed very smoothly. Ru.

Note that during the above control, if the manual stop command means 47, such as the operating lever of a remote control valve, is operated, each of the above controls is immediately canceled, and each electromagnetic proportional The pressure reducing valve 41.42 is activated, the control valve 43.44 is returned to the neutral position and the motor 45.46 is stopped or activated in the danger avoidance direction. This ensures safety.

Other Embodiments The apparatus of the present invention is not limited to the tower crane of the above embodiment, but can also be applied to ordinary jib cranes, rough terrain cranes with telescoping booms, and the like.

FIG. 8 is a side view showing an example of a rough terrain crane to which the device of the present invention is applied, and FIG. 9 is a conceptual diagram showing the deflection of the telescopic boom of the rough terrain crane. Figures 8 and 9
In the figure, a telescopic boom 7 is supported by an upper revolving body 6 rotatably provided on a traveling vehicle body 5 via a hydraulic cylinder 8 for raising and lowering the boom. 9 indicates a drum for hoisting and lowering the hoisting rope.

When performing ground cutting control of the suspended load 4 with this rough terrain crane, the load depends on the working conditions and working posture, that is, the boom length/@, the boom angle θ8, the suspended load on the hoisting rope 3, the swing angle, etc. - A characteristic curve of deflection is stored in advance in a storage device, and the boom length detected by the boom length detector, boom angle detector, suspended load detector, and swing angle detector at the start of ground cutting control. l II %
Initial values I of boom angle θB, hanging load, and swing angle
BO1θBO... and the load stored in the sound absorber -
Based on the deflection characteristic curve, the boom tip position is determined, and target values for the boom raising speed and hoisting rope hoisting/lowering speed corresponding to the boom tip position are calculated. The forward control causes the boom 7 to be raised and the hoisting rope 3 to be hoisted up and down.

In addition, from the momentary detection values of each of the above detectors and the above load-deflection characteristic curve, the horizontal displacement ΔH of the boom tip is determined.
is determined, and the position control of the boom 7 and the hoisting and lowering of the hoisting rope 3 are controlled by the same feedback control as described in (1) above, and the suspended load 4 is efficiently and smoothly taken off the ground. .

In this case, a load-deflection characteristic curve will be used, but the raising of the boom 7 and the raising and lowering of the hoisting rope 3 will be linked to each other, and dual control of feedforward and feedback will be performed. As a result, control accuracy can be improved compared to the above-mentioned conventional techniques.

〔Effect of the invention〕

As described above, the present invention has the following effects.

In other words, after setting the jib (or boom) tip to the initial position, simply operating the ground cutting control start command means will set the jib raising speed target value corresponding to the initial position of the jib tip and the hoisting rope hoisting/lowering speed target value. and control the raising speed of the jib and the hoisting and lowering speed of the hoisting rope by feedforward control based on the target value, and further,
The control results are tracked and feedback control is used to control the position of the jib tip and the amount of change in the hoisting rope, so the jib length (boom length) and initial posture are not affected. Moreover, even if the magnitude of the suspended load is not known, the position of the hoisting rope can always be corrected on the vertical line, and the suspended load can be cut vertically without swinging. Moreover, in addition to controlling the position of the tip of the jib, the amount of change (increase) in the suspended load is also controlled, so the suspended load can be cut off the ground efficiently with continuous operation.

In particular, as claimed in claim 2, by lowering the hoisting rope when the initial position of the jib is below the set value, it is possible to prevent the rope tension from increasing rapidly and correct the amount of horizontal displacement at the tip of the jib. It is possible to reliably prevent a suspended load from being cut off before it is lifted off the ground. In addition, when the initial position of the jib is greater than the set value, by hoisting the hoisting rope, it is possible to prevent the increase in the tension of the hoisting rope from decreasing rapidly, and to quickly break the ground within the target time. It can be performed.

As in claim 3, the first. The signal processing means regulates the maximum and minimum values of the feedforward control signals for raising the jib and hoisting and lowering the hoisting rope, which are input from the second calculation means, so that these control signals are optimized. By limiting the tension within the range, the tension applied to the hoisting rope will not suddenly increase and the rope will break quickly, or the amount of increase in rope tension will become too small and the breaking will be delayed, so it will always be optimal. You can perform ground cutting in any state, increasing efficiency.

By configuring the feedforward control signal to gradually increase along a predetermined start-up pattern as in claim 4, it is possible to prevent a sudden shock from occurring in the jib etc. at the start of ground cutting control. , ground cutting control can be started very smoothly.

As in claim 5, a time differentiator for the amount of change in the suspended load;
By providing the ground cutting end discriminator, the end point of the ground cutting can be automatically determined, each drive device can be automatically stopped to complete the ground cutting, and unnecessary movements can be eliminated.

According to claim 6, by configuring the signal processing means to gradually reduce the control signal for each drive device along a predetermined stop pattern, a sudden shock is generated in the jib etc. at the end of the ground cutting control. can be prevented,
Ground cutting control can be ended very smoothly.

As claimed in claim 7, when applied to a tower crane, there is no need to additionally provide an angle detector, etc., and control can be performed using a detector of an overload prevention device that is generally equipped on the crane. Easy to implement.

As claimed in claim 8, it can be applied to a hydraulically driven crane in which a hydraulic motor is used to raise and lower a jib and to raise and lower a hoisting rope. This also makes it possible to control ground cutting smoothly.

As claimed in claim 9, even in the case of a boom in which the jib is supported by the upper revolving structure of a crane so that it can be raised and lowered, especially in the case of a telescopic boom, it is possible to control the ground cutting, and in this case as well, the existing detector can be used. It can be used, controlled and easily implemented.

As claimed in claim 10, it can also be applied to a crane whose boom is raised and lowered by a hydraulic cylinder, and in this case as well, delicate control is possible by a combination of an electromagnetic proportional pressure reducing valve and a control valve, and ground cutting control can be performed smoothly. I can do it.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing an embodiment of the present invention, Figure 2 is a conceptual diagram showing an example of a tower crane to which the present invention is applied;
FIG. 3 is a diagram showing an example of the output pattern of the feedforward control signal for raising the jib, FIG. 4 is a diagram showing an example of the output pattern of the feedforward control signal for hoisting and lowering the hoisting rope, FIG. 5 is a relationship diagram between the control signal before nonlinear compensation and the control signal after linear compensation, and FIG. 6 is a relationship diagram between the control signal input to the electromagnetic proportional pressure reducing valve and the pilot pressure output from the pressure reducing valve. FIG. 7 is a diagram showing the relationship between the pilot pressure and the flow rate flowing into the hydraulic motor, and FIG. 8 is a side view showing an example of a rough terrain crane to which the present invention is applied.
FIG. 9 is a conceptual diagram showing the deflection state of the boom. So... tower 2... jib, 3... hoisting rope, 4
... Hanging load, 5... Vehicle body, 6... Upper revolving structure,
7...Telescopic boom, 8...Hydraulic cylinder for boom hoisting, 10...Crane body, 1...Tower height detector, 12...Tower angle detector, 13...Jib length Detector, 14... Jib angle detector, 15... Hanging load detector, 20... Controller, 2... Ground cutting control start command means, 22... Input device, 23... Target value calculating means, 24... first calculating means, 25... second calculating means, 26... displacement amount calculating means, 27...
Third calculation means, 28... time differentiator, 29... ground cutting end determination means, 30... fourth calculation means;
・Automatic stop command means, 32°33... signal processing means,
40... Hydraulic system control means, 41.42... Control valve, 43.44... Electromagnetic proportional pressure reducing valve, 45
．． 46...Hydraulic motor, 47...Manual stop command means.

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 ground cutting control; A target value calculation means for calculating a target value and a target value of a hoisting rope hoisting/lowering speed, and outputting a feed forward control signal for jib raising based on the jib raising speed target value calculated by the target value calculating means. a first calculation means, and a second calculation means that outputs a feedforward control signal for hoisting rope hoisting and lowering based on the hoisting rope hoisting and lowering speed target value calculated by the target value calculation means; The amount of displacement of the jib tip position is determined based on the value detected by the tip position detection means, and the amount of displacement is used as a deviation, and a feedback control signal for raising the jib is output to control the position of the jib tip so that the deviation becomes zero. The third calculation means calculates the amount of change in the suspended load per unit time based on the detected value by the suspended load detection means, and adjusts the hoisting rope so that the deviation between the amount of change and the set value is zero. a fourth calculation means for outputting a feedback control signal for hoisting and lowering; and driving a jib hoisting drive device and a hoisting rope hoisting and lowering drive device in accordance with the control signals output from each of the above calculation means. 1. A vertical ground cutting control device for a suspended load in a crane, characterized in that it is equipped with a control means for controlling. 2. The jib tip position detection means has a jib angle detector, and the target value calculation means determines the initial jib angle when the initial value of the jib angle detected by the jib angle detector is larger than the set value. Calculate the target hoisting speed to hoist the hoisting rope at a speed corresponding to the value, and if it is less than the set value, calculate the target lowering speed to lower the hoisting rope at a speed corresponding to the initial value of the jib angle. The vertical ground cutting control device for a suspended load in a crane according to claim 1, characterized in that it is configured as follows. 3. Claim 1, further comprising signal processing means for regulating the maximum value and minimum value of each feedforward control signal output from the first and second calculation means.
Or a vertical ground cutting control device for a suspended load in a crane according to 2. 4. A signal processing means is provided for gradually increasing the rise pattern of each feedforward control signal outputted from the first and second calculation means from a reference value to a target control value within a set time. A vertical ground cutting control device for a suspended load in a crane according to any one of claims 1 to 3. 5. A differentiator that time-differentiates the amount of change in the suspended load detected by the suspended load detection means, and the ground cutting control is terminated depending on whether or not the time differential value is within a set range for a set time. A ground cutting end determining means for determining whether or not the ground cutting is completed, and a control stop command means for outputting a control stop signal to each of the drive devices based on the end signal from the determining means. 5. A vertical ground cutting control device for a suspended load in a crane according to any one of 1 to 4. 6. The present invention further comprises signal processing means for gradually decreasing the control signal for each of the drive devices from the control value to the reference value within a set time based on the control stop signal from the control stop command means. 5. A vertical ground cutting control device for a suspended load in the crane according to 5. 7. The jib is supported at the upper end of the tower so that it can rise and fall freely, and the means for detecting the jib tip position is based on the tower height, the tower angle,
According to any one of claims 1 to 6, the jib includes detectors for measuring jib length and jib angle, and the jib tip position is determined based on the detected values by these detectors. A vertical ground cutting control device for a suspended load in the crane described above. 8. The jib hoisting drive device has a hydraulic motor that drives the jib hoisting rope winding drum, and the hoisting rope hoisting and lowering drive device has a hydraulic motor that drives the hoisting rope winding drum. , a control valve in which the control means controls the inflow flow rate of pressure oil from the hydraulic source to each of the hydraulic motors, and an electromagnetic proportional pressure reducing valve that outputs a hydraulic signal for switching control of each control valve in accordance with each of the control signals. 8. A vertical ground cutting control device for a suspended load in a crane according to claim 7. 9. The jib is a boom supported on the upper revolving structure of the crane so as to be able to rise and fall freely, and the jib tip position detection means includes a boom length detector and a boom angle detector,
The vertical position of a suspended load in a crane according to any one of claims 1 to 6, wherein the boom tip position is determined by the boom length and boom angle detected by each of the detectors. Cutting control device. 10. The jib hoisting drive device has a boom hoisting hydraulic cylinder, and the hoisting rope hoisting and lowering drive device has a hydraulic motor that drives a winding drum of the hoisting rope, and the hydraulic cylinder is connected to the hoisting rope from a hydraulic source. and a control valve that controls the inflow flow rate of pressure oil to the hydraulic motor, and an electromagnetic proportional pressure reducing valve that outputs a hydraulic signal for switching control of each control valve in accordance with each of the control signals. The vertical ground cutting control device for a suspended load in a crane according to claim 9.