JPH07215680A - Lifted load locus controller for crane - Google Patents

Abstract

PURPOSE:To move a lifted load at an arbitrary locus by the simple operation of an operator at the time of moving the load lifted by a crane. CONSTITUTION:A crane control circuit is provided with a means 29 for detecting the speed of a hook hoisting/lowering drum 16, and a means for detecting the elevation angle of a boom to compute the present head of a hook from respective detected values with a control part 31. Such a control characteristics as changes the head correction value of the hook at a prescribed percentage for a change in the elevation angle of the boom is memorized to determine the target head correction value of the hook from the control characteristics. The target head value of the hook is computed from these data to adjust the delivery amount or winding amount of the hook hoisting/lowering rope.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane locus control system for a suspended load, and more particularly to improvement of operability in moving a suspended load.

[0002]

2. Description of the Related Art As a conventional crane locus control device for a suspended load, for example, a horizontal movement control method disclosed in Japanese Patent Laid-Open No. 63-60897 is known. This suppresses the control signal to the elevation drive mechanism according to the length of the boom and the number of ropes between the boom and the suspended load. The maximum value and the minimum value assumed for the above are divided into areas, the limit value of the drive control signal to the elevation drive mechanism is set for each area, and the drive control signal to the hoisting and lowering drive mechanism reaches the maximum value. In this case, the drive control signal for the elevation drive mechanism is lowered.

Further, like the horizontal movement control device described in Japanese Patent Publication No. 3-53237, the boom elevation and hoisting and lowering amounts are controlled on the basis of the operation amount of the boom elevation lever to improve controllability at the time of starting. Improved ones are also known.

[0004]

As described above, a conventional crane locus control system for a suspended load of a crane includes a feedforward control system based on the boom elevation angle and a boom depression lever operation amount, and a hoisting and lowering rope. Although it is composed of a feed-back or take-up amount feedback control system, the control method is complicated and it is difficult to perform accurate control.

In particular, when the suspended load is moved along the slope, or when the suspended load is moved along an arbitrary path when avoiding an obstacle on the way, the elevation of the boom and the rope hoisting and lowering of the hook are required. The combined operability is not good, which is a cause of operator fatigue. Therefore, when moving the suspended load of the crane, there arises a technical problem to be solved in order to move the suspended load on an arbitrary trajectory by a simple operation of the operator, and the present invention solves this problem. The purpose is to do.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been proposed in order to achieve the above object, and comprises a boom depression / elevation angle control mechanism and a rope hoisting / lowering control mechanism for a hanging load hook. Means for detecting the depression / elevation angle of the hook, a means for detecting the number of rotations of the hook hoisting / lowering drum, a means for calculating the current lift value of the hook from the detection values of the respective detection means, and a change in the depression / elevation angle of the boom. A means for storing a control characteristic for changing the hook lift correction amount at a predetermined rate, and a target hook lift correction calculated from the current hook lift value and the stored control characteristics. The target lift value of the hook is calculated from the amount and the rotation speed of the drum is changed based on the target lift value, and a control unit is provided to adjust the unwinding amount or the winding amount of the hook hoisting and lowering rope. And there is provided a locus control system for suspended load of the crane.

[0007]

The hook lift value is calculated by the control unit from the boom depression angle detected by the detection means and the rotation number of the hook hoisting / lowering drum. Further, control characteristics are stored in advance in the storage means so that the hook lift correction amount is changed at a predetermined rate with respect to the change in the boom depression angle.
Then, the target lift value of the hook is calculated by the control unit from the current lift value of the hook calculated from each of the detected values and the target lift correction amount of the hook calculated from the stored control characteristics.

The control unit changes the number of rotations of the drum based on the target lift value, and adjusts the feed amount or pre-take amount of the hook hoisting and lowering rope. Thus, as the boom moves, the suspended load is moved along the correct trajectory along the preset control characteristics.

[0009]

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a control circuit of a trajectory control device for a suspended load of a crane. Reference numeral 11 is a hydraulic pump for hoist hoisting and lowering drums, 12 is a hydraulic pump for raising and lowering a boom, and the discharge oil of the hydraulic pump 11 is directional control. It is supplied to the hydraulic motor 14 for rotating the drum via the valve 13. Then, the rotation of the hydraulic motor 14 is transmitted to the drum 16 for hoisting and lowering the hook via the transmission mechanism 15. On the other hand, the oil discharged from the hydraulic pump 12 is supplied to a boom elevation hydraulic motor 18 via a direction control valve 17.

Direction control valve 13 for hoisting and lowering the hook
Is operated by the operating lever portion 19, but an electromagnetic switching valve 21 is provided in the pilot oil passage 20 and an electromagnetic switching valve 23 is provided in the pilot oil passage 22. Further, the directional control valve 17 for raising and lowering the boom is operated by the operating lever portion 24, but pilot pressure detecting means 27 and 2 such as pressure switches are provided in the pilot oil passages 25 and 26, respectively.
Interpose 8. Further, the drum 16 is provided with a detecting means 29 such as a proximity switch to detect the number of rotations of the drum 16, and a boom (not shown) is provided with a detecting means 30 such as a potentiometer to detect the depression and elevation angle of the boom. The detection values of the equality detection means 27 to 30 are input to the control unit 31.

When the control mode is entered, the boom operating lever portion 24 is operated with the hook hoisting and lowering operating lever portion 19 kept at the neutral position. For example, when the operation lever portion 24 is operated to the pilot oil passage 25 side, the pilot port 32a of the directional control valve 17
Pilot pressure is applied to the spool, the spool moves from the neutral position 17a to the position 17b, the hydraulic motor 18 rotates in the forward direction, and the depression angle of the boom increases.

At this time, the detection means 29 detects the current rotational position of the drum 16, the detection means 30 detects the current depression and elevation angle of the boom, and inputs the detected value to the controller 31. Then, the lift value H _ST of the hook at the start of control is calculated. Then, the detecting means 27 and 28
Thus, the pilot pressure in the pilot oil passages 25 and 26 is detected, and the control unit 31 recognizes that the operation lever unit 24 has been operated to the side of increasing the boom depression angle.

In that case, the lift value of the hook is corrected in accordance with the change in the elevation angle of the boom. Although the amount of hook lift correction varies depending on the work content of the crane, for example, as shown in FIG. 2, the control characteristics are set so that the amount of hook lift correction increases proportionally to the amount of change Δθ in the boom depression angle. Then
The above-mentioned control characteristics are stored in advance in the storage means provided in the control unit 31. Then, the target lift correction amount H _C of the hook is obtained from the stored control characteristics, and the target lift value H of the hook is calculated by the following equation.

H = H _ST + H _C (Equation 1) Then, based on the target lift amount H of the hook calculated from Equation 1, feedback control as shown in FIG. A control signal is sent to the regulator 33 to adjust the tilt angle of the hydraulic pump 11 to change the discharge amount of the hydraulic pump 11.

As described above, when the operation lever portion 24 is operated to the pilot oil passage 25 side, the solenoid 34 of the electromagnetic switching valve 21 is turned on and the spool is moved to the position 21b. In such a case, the oil discharged from the hydraulic pump 35 is led to the pilot port 36a of the directional control valve 13, the hydraulic motor 14 rotates in the normal direction, and the rope for winding up and down the hook wound around the drum 16 is wound up. The target lift value H of the hook increases in proportion to the increase in the depression / elevation angle of the boom, and the suspended load can be moved while being pulled up along the slope.

On the other hand, when the operation lever portion 24 is operated to the pilot oil passage 26 side, the hydraulic motor 18 reversely rotates reversely to decrease the boom depression angle and electromagnetic switching. The solenoid 37 of the valve 23 is turned on to rotate the hydraulic motor 18 in the reverse direction, and the rope for hoisting and lowering the hook is fed out. Also at this time, the target lift correction amount H _C of the hook is calculated from the stored control characteristics,
The feedback control is performed by calculating the target lift value H of the hook by the equation 1.

Thus, the operation lever portion 2 for raising and lowering the boom is raised.
Only by operating 4, the amount of winding or the amount of winding of the hook hoisting and lowering rope is automatically controlled on the basis of the preset control characteristic, and the operability is remarkably improved. Further, by changing the control characteristics shown in FIG. 2 in advance according to the work content, it is possible to control the movement of the suspended load along an arbitrary trajectory.

The present invention can be modified in various ways without departing from the spirit of the present invention, and it goes without saying that the present invention extends to such modifications.

[0019]

As described in detail in the above one embodiment, the present invention stores in advance a control characteristic for changing the hook lift correction amount at a predetermined rate with respect to the boom depression angle. Accordingly, the lift value of the hook is calculated based on the control characteristic. Therefore, if the control characteristic is changed in advance according to the work content, the trajectory of the suspended load can be arbitrarily controlled by a simple operation, the operability can be improved, and the operator's fatigue can be reduced.

[Brief description of drawings]

FIG. 1 is a control circuit diagram of a suspended load trajectory control device for a crane that is an embodiment of the present invention.

FIG. 2 is a graph showing control characteristics.

FIG. 3 is a block diagram of control.

[Explanation of symbols]

 11, 12 Hydraulic pump 14, 18 Hydraulic motor 16 Drum 27, 28 Detecting means 29, 30 Detecting means 31 Control part 33 Regulator

Claims (1)

[Claims] 1. A boom depression / elevation angle control mechanism and a rope lifting / lowering control mechanism for a hanging hook, and means for detecting the boom depression / elevation angle and means for detecting the number of rotations of the hook hoisting / lowering drum. And means for calculating the current hook lift value from the detection values of the respective detection means, and a control characteristic for changing the hook lift correction amount at a predetermined ratio with respect to the change in the boom depression angle. Means for calculating the target lift value of the hook from the current lift value of the hook and the target lift correction amount of the hook obtained from the stored control characteristic, and the drum based on the target lift value. A crane locus control device for a suspended load of a crane, characterized in that a control unit is provided for changing the number of rotations of the crane to adjust the amount of winding or winding of the hook hoisting and lowering rope.