JP2022166468A - Method of controlling winding up/down of crane with double rope type bucket - Google Patents

Abstract

To provide a method of controlling winding up/down of a crane with a double rope type bucket which is easy to use and has excellent conveyance efficiency.SOLUTION: When an opening/closing state of a bucket GB is between the vicinity of a closing deceleration position of the bucket GB and a closing side, the output speed of a support motor and an opening/closing motor is controlled to be reduced in proportion to the magnitude of a load at the time of winding up and the output speed thereof is controlled to be increased in proportion to the magnitude of the load at the time of winding down. When the opening/closing state of the bucket GB is between the vicinity of the closing deceleration position of the bucket GB and an opening side, the controlling is performed such that a speed deviation is reduced regardless of the magnitude of the load at the time of winding up/down. At the time of winding down, a speed control range is widened to a range in which the speed of the opening/closing motor exceeds a rated speed such that the speed of the opening/closing motor is made faster than that of the support motor so as to perform the opening operation during winding down. When the bucket GB is positioned at an opening end position, the speed of the support motor is equalized to that of the opening/closing motor and the winding down is performed while maintaining the state of the opening end position.SELECTED DRAWING: Figure 9

Description

In the present invention, the hoisting device of a crane is hoisted and lowered by two independent motors of the same capacity, a support motor and an opening/closing motor, and two types of support rope and opening/closing rope are suspended from the independent support device and the opening/closing device. A method for controlling a support motor and an opening/closing motor for hoisting and lowering a bucket in a crane equipped with a double-rope bucket (hereinafter sometimes simply referred to as a "bucket") that is moved by ropes of It is about.

The operation of the double rope type bucket is performed by manipulating the movements of two kinds of ropes, a supporting rope and an opening/closing rope.
In the past, this operation used a method using a differential speed reducer or a method using a clutch, but due to the problems of manufacturability and maintainability of the mechanical system, it is now necessary to separate support and opening/closing. A method of controlling two winding devices by electrical control has become common.
However, in a double rope bucket whose load balance between support and opening/closing changes depending on the state of the bucket, it is difficult to balance the rope between support and opening/closing. technology was required.

In order to deal with this problem, conventionally, various control methods for the bucket support motor and opening/closing motor have been proposed (see, for example, Patent Documents 1 to 4).

JP-A-2002-128466 JP-A-4-358696 JP-A-1-203194 JP-A-1-172198

By the way, in a conventional double-rope bucket-mounted crane, for example, when the bucket is open, most of the load of the bucket is shared by the support motor, and the opening/closing motor hardly bears the load of the bucket. Therefore, if an induction motor is used, motor slippage will affect the speed of the support motor during hoisting, and conversely, the speed of the support motor will be faster than that of the open/close motor during hoisting. The difference in speed between the support motor and the opening/closing motor is such that the bucket closes both when the bucket is being hoisted and when it is lowered, and the bucket closes without permission while the bucket is being hoisted and lowered. For this reason, when the bucket is fully opened and lowered in order to grab bulk cargo, the bucket is about to close before it lands on the floor, so the bucket must be opened again before it lands on the floor. I had to let it go and grab it.

In addition, when the bucket is closed and gripped, if the speed of the support motor is faster than that of the open/close motor during hoisting, the bucket opens and the gripped loose cargo is dropped, and the speed of the support motor is faster than that of the open/close motor. When it slows down, the support rope becomes slack and the switchgear becomes overloaded, causing heat damage to the switching motor and switching speed control device.
Conversely, when lowering the bucket, if the speed of the support motor is slower than that of the opening/closing motor, the bucket will open and the loose cargo that is being held may be dropped. The switchgear became overloaded, causing heat damage to the switch motor and switch speed controller.

In view of the problems of the conventional crane with a double rope bucket, the present invention controls the support motor and the opening/closing motor of the double rope bucket according to the situation of the bucket, and is easy to use and transport efficiency. To provide good control of hoisting and lowering of a crane with a double rope type bucket.

In order to achieve the above object, a method for controlling the hoisting and lowering of a crane with a double-rope bucket according to the present invention provides a method for hoisting and lowering a double-rope bucket with two types of equal-capacity hoisting devices that are independent of a support motor and an open/close motor. A method for controlling the hoisting and lowering of a crane with a double-rope bucket, comprising:
When the open/closed state of the bucket is near the closed deceleration position of the bucket (a position slightly opened from the closed end position) to the closing side (it is judged that the bucket is closed and the cargo is grasped, and the hoisting or The speed control characteristics of the support motor and the open/close motor during hoisting are assumed to be proportional characteristics that proportionally fluctuate the torque with respect to the amount of speed deviation.), the output speed of the support motor and open/close motor is As the size of the load increases, the speed is controlled so that it slows down in proportion to the size of the load. At this time, the ratio of the speed to the load is set to the same ratio for both the support motor and the open/close motor, so that the load sharing between the support motor and the open/close motor is the same, thereby maintaining the state of gripping the cargo. It can be hoisted and lowered while
When the open/closed state of the bucket is from the vicinity of the closed deceleration position of the bucket (a position slightly opened from the closed end position) to the open side (a position where the cargo cannot be gripped), the load will be large during hoisting and lowering. (The speed control characteristics of the support motor and the open/close motor when lifting or lowering are controlled to reduce the speed deviation regardless of the load fluctuation. The speed deviation is reduced, and the speed fluctuation due to the load of the support motor and the opening/closing motor is reduced.) In addition, when lowering, the speed control range is expanded to the range where the speed of the opening/closing motor exceeds the rated speed, and the opening/closing is performed by the support motor. By increasing the speed of the motor, the opening operation is performed while lowering the load. When lowering the bucket when the open/close position is not at the open end position, the lowering speed of the open/close motor is made faster than the rated speed than the lowering speed of the support motor so that the bucket moves toward the open end position while lowering. ), and when the bucket is at the open end position, the speeds of the support motor and open/close motor are made equal to lower the bucket while maintaining the state of the open end position (when the open end position is reached, the support motor and open/close The open end position is actively maintained by winding down while the motor speed remains the same.)
It is characterized by

In this case, when the opening/closing state of the bucket is on the closing side from the vicinity of the closing deceleration position of the bucket, when the speed or torque after the acceleration of the support motor and the opening/closing motor become equal, the motor torque If there is spare power, it is possible to increase the speed up to the maximum speed that each motor can output with respect to the size of the load at that time.
In particular, when the bucket is closed and the cargo is being hoisted, when the load sharing after the acceleration of the support motor and the open/close motor becomes the same, the speed at the time of hoisting decreases due to the proportionality characteristic. The speed command is increased by 1, and the slowed speed is supplemented. If the support motor and the open/close motor have a surplus power for the load size, the speed of the support motor and the open/close motor is further increased by the surplus power. By increasing the speed, it is possible to improve the transportation efficiency.

According to the method for controlling the hoisting and lowering of a crane with a double-rope bucket of the present invention, the supporting motor and the opening/closing motor are appropriately controlled according to the state of the bucket, the slackness of the supporting rope or the opening/closing rope is reduced, and It is possible to provide a crane with a double-rope type bucket that performs effective high-speed operation, is stable in operation, is easy to operate, and has good transport efficiency.

FIG. 4 is a plan view of a crane retractor that controls a double rope bucket; It is structural explanatory drawing of a double rope type bucket. It is explanatory drawing of the opening-and-closing rope of a double rope type bucket. FIG. 10 is an explanatory diagram of the arrangement of an opening/closing position detector for a double-rope bucket; It is explanatory drawing of the load sharing of the support motor of a double rope type bucket, and an opening-and-closing motor. FIG. 4 is a torque characteristic diagram of a support motor and an opening/closing motor when a double rope type bucket is not gripped; FIG. 4 is a torque characteristic diagram of a support motor and an opening/closing motor when a double rope type bucket is gripping; 4 is a control block diagram of a speed control system that generates torque characteristics of a support motor and an opening/closing motor; FIG. FIG. 10 is an operation explanatory diagram of control during lowering of the double rope type bucket; It is explanatory drawing of the bridge state of a hopper.

Hereinafter, a method for controlling the hoisting and lowering of a double-rope bucket-equipped crane according to the present invention will be described with reference to the drawings.

FIG. 1 shows a plan view of a crane winding device for operating a double rope bucket.
A support motor HM with a speed detector PG is connected via a brake BR and a speed reducer GR to a support drum HD, around which a support rope HW is wound.
A load cell LC is attached to a portion that catches the load applied to the support rope HW (for example, a bearing portion of the support tram HD), and a support position detector HP is attached to the shaft of the support drum.
The opening/closing device also has the same structure as the support device and has the same capacity as the supporting device, and the support and the opening/closing are arranged independently of each other. An opening/closing rope GW is wound around the connected opening/closing drum GD. Also, a load cell LC and an open/close position detector GP are attached.

FIG. 2 shows the structure of the double rope bucket, and FIG. 3 shows the opening and closing ropes of the double rope bucket.
A support rope HW is fixed to the upper sheave box HB and supports the entire bucket.
A connecting rod LL is connected to the upper sheave box HB by means of a pin link structure, and is connected to the shell CL. The shells CL are linked together by a lower sheave box BB. A claw TA is attached to the tip of the shell CL.
Here, the opening/closing rope GW is hung multiple times through the sheave SH attached to the lower sheave pin BS in the lower sheave box BB and the sheave SH attached to the upper sheave pin HS in the upper sheave box HB (Fig. 3 4. In the example shown in FIG. 2, four ropes are hung.), and the end of the opening/closing rope GW is fixed to the upper sheave pin HS by the cotter sheave CS.

The movement of the bucket GB is the movement of the support rope HW and the opening/closing rope GW, and performs five operations of opening, closing, gripping, lifting, and lowering.
The opening operation is performed by lowering the open/close rope GW while the support rope HW is stopped.
The closing operation is performed by hoisting the open/close rope GW while the support rope HW is stopped.
The gripping operation is performed by loosening the support rope HW and sinking the bucket GB by its own weight while moving the open/close rope GW in the closing direction of the hoisting bucket to control the slack in the support rope HW.
The hoisting operation is performed by hoisting both the support rope HW and the opening/closing rope GW at a constant speed, and the lowering operation is performed by lowering both the support rope HW and the opening/closing rope GW at a constant speed. becomes.
Here, if the speeds of the support rope HW and the opening/closing rope GW are not constant, the bucket may close or open, or one of the ropes may become slack while the bucket is being hoisted or lowered.
In order to prevent this, the support ropes HW and the open/close ropes GW are controlled in the case of hoisting or lowering as described below.

FIG. 4 shows the detected positions of the open/closed position detector of the double-rope bucket.
(1) in FIG. 4 is the state of the open end position GO of the bucket GB when the opening operation is stopped by the open end stop limit switch. ing. (2) in FIG. 4 shows the state of the open deceleration position GOD, which is provided in front of the opening deceleration distance in order to decelerate to a low speed before the open end position GO during the opening operation of the bucket GB. (4) in FIG. 4 shows the state of the closed end position GC of the bucket GB when the closing operation is stopped by the closed end stop limit switch, and the shell CL is in the state of no load, and the support rope is in a position where the support rope does not loosen. is set. (3) of FIG. 4 shows the state of the closing deceleration position GCD, which is provided before the closing deceleration distance in order to decelerate to a low speed before the closing end position GC during the closing operation of the bucket GB.
Since the relative difference between the movement amount of the support rope and the movement amount of the opening/closing rope is the opening/closing operation, the detection of the opening/closing position is performed by detecting the rotation of the opening/closing drum GD and the support position detector HP that detects the rotation of the support drum HD. The difference in rotation between the two detectors of the open/close position detector GP is used to detect the degree of opening/closing. The detection method includes a method of electrically obtaining a rotation difference, or a method of inputting the rotations of both the support drum HD and the opening/closing drum GD to a differential speed reducer to mechanically obtain the rotation difference, and using the rotation difference to determine the degree of opening and closing. There is a method of detection, and the like.

(5) in FIG. 4 shows a state in which a large amount of loose cargo HO is caught between the shells CL and gripping force is exerted. The state of this grasping position GG is not the state detected by the position detector. Both the support rope HW and the open/close rope GW support the load equally as shown in FIG. 5(3). If the opening/closing rope GW is slightly loosened from this gripping position GG, the bulk cargo HO will be dropped, and if the opening/closing rope GW is slightly tightened too much, the support rope HW will be loosened as shown in FIG. 5(4). In this way, the gripping position GG has a delicate positional relationship, and both the support rope HW and the opening/closing rope GW are present in a position where they can be maintained by sharing the load. should be split equally at 50:50.
This gripping position GG slightly changes depending on the state of the loose cargo HO being gripped, and always exists between the closed deceleration position GCD and the closed end position GC.
When the bucket GB is empty, the position of the closed end position GC becomes the gripping position GG.
The opening/closing position of the closed deceleration position GCD, which is always located on the opening side from the gripping position GG, is a state in which the bucket GB alone is empty, in a state in which the bulk material HO cannot be held in the bucket GB.

In the structure of the opening/closing rope GW shown in FIG. If the number is four, the length of the open/close rope GW between the open end position GO and the closed end position GC of the bucket GB is 5 m (1.25 m×4 ropes). The open deceleration position GOD at this time is set at a position about 1.2 m before the position of the open/close rope GW at the open end position GO. The closing deceleration position GCD is set at a position about 0.6 m before the position of the open/close rope GW at the closed end position GC. At this time, the deceleration distance differs between the open side in which the load hinders deceleration and the closed side in which the load helps deceleration.

FIG. 5 shows the distribution of the load applied to each of the support ropes HW and the opening/closing ropes GW in each state of the bucket GB.
In the state of (2) in FIG. 5 where the bucket GB is not gripped, the load of the bucket GB supported by the opening/closing rope GW is the load supported by the connecting rod LL among the weights of the shell CL and the lower sheave box BB. , and divided by the number of hooks on the opening and closing rope GW (4 in the case of Fig. 3, because it is four hooks) is the load on the opening and closing rope GW, which is less than 15% of the load on the bucket GB. Only a small load is supported by the opening/closing rope GW, and the remaining 85% or more of the load is supported by the support ropes. Furthermore, when the bucket GB is fully opened in the state of FIG. 5 (1) and the opening/closing rope GW is slack, the support rope HW bears the entire load of the bucket GB, and the opening/closing rope GW bears no load. It becomes a state of not sharing.

When an induction motor is used for the support motor HM and the open/close motor GM and they are operated without speed control, the support motor HM is pulled by the load and the motor The speed of the open/close motor, which has a light load and less motor slip, is faster than that of the supporting motor. The speed difference between the support motor HM and the open/close motor GM causes the bucket GB to move in the closing direction. When the bucket is lowered, the support motor HM is pulled by the load and becomes faster than the open/close motor GM by the amount of motor slippage.
Therefore, when the opening/closing state of the bucket GB is on the opening side of the closed deceleration position GCD, it means that the loose cargo HO is not being gripped. By adding speed control to achieve the characteristics shown, the speed is kept constant regardless of the size of the load, and the phenomenon of closing during hoisting and lowering is minimized.
However, even with the characteristics shown in FIG. 6, there actually exists a slight steady-state deviation, and when the acceleration torque during acceleration is added to the load torque of 85% or more of the support motor HM, the torque limiter LM ( 150% in the embodiment), and a slight closing phenomenon may occur during acceleration.
In order to eliminate this slight closing phenomenon, when the bucket GB is on the opening side of the closed deceleration position GCD, the load sharing of the open/close motor GM is small, and the rated speed is increased by the excess power of the open/close motor GM. By increasing the speed of the open/close motor GM faster than that of the support motor HM, the opening operation is performed while winding down as shown in FIG. eliminate the phenomenon.

In the characteristic diagram of FIG. 6, the horizontal axis is the speed ω and the vertical axis is the torque T. The plus side of the torque T is the hoisting side and the minus side of the torque T is the hoisting side.
As shown in the characteristic curve of FIG. 6, the speed ω with respect to the torque change is a curve that rises straight above the speed target value ω ^* without speed change.
However, in practice there is a slight steady state deviation.
The curve that rises straight above the speed target value ω ^* reaches the torque limiter LM (150% in the example) when the output torque reaches the limit of its ability, and the speed slows down when winding up and speeds up when winding down.
The direction in which the steady-state deviation and the torque limiter LM are generated is the direction in which the bucket GB is closed both during hoisting and hoisting.
If the speed ω exceeds 100% of the rated speed, the torque T that can be output decreases as the speed ω increases due to the problem of motor characteristics.

When the bucket GB is closer to the closed deceleration position GCD than the closed deceleration position GCD, it is determined that the bulk cargo is being gripped. At the gripping position GG shown in (5), the state of load sharing 50:50 in (3) of FIG. 5 can be created and maintained. At this time, by giving the same inclination and the same speed target value to both the support motor HM and the open/close motor GM, the load sharing between the support motor HM and the open/close motor GM becomes 50:50. The characteristic in Fig. 7 is that when a load is applied to the hoisting side, the speed decreases in proportion to the magnitude of the load, and conversely, the speed increases as the load increases on the hoisting side (negative torque side). The characteristic of the embodiment of FIG. 7 is such that when the load torque is 100%, the speed deviation of the embodiment is 8%.
The slope of the control characteristic in FIG. 7 is similar to the slip characteristic when the induction motor is operated without speed control. The slope of the characteristic is set to 8% because the load sharing between the support motor HM and the open/close motor GM is more positively converged to the equally balanced state of 50:50 more quickly, and more stably balanced equally 50:50. This is for holding the state.
In other words, the phenomenon that the bucket GB closes arbitrarily during hoisting and lowering due to the slippage of the induction motor can be more actively controlled by performing speed control when it is on the closing side of the closed deceleration position GCD. I am trying to create that state.
At this time, if the slope of the characteristic in FIG. 7 is left at 8% for the support motor HM and the slope of only the open/close motor GM is set to 7%, for example, the load sharing of the open/close motor GM can be increased, but the bucket GB There is no need to change the load sharing in terms of the characteristics of , ideally the load sharing is 50:50, and the characteristics of the support motor and the open/close motor are ideally the same.

When the support motor ^HM and the opening/closing motor GM are actually moved with the control characteristics shown in FIG. When hoisting, for example, if the share of the support tends to increase, the speed of the support slows down, and the speed on the opening/closing side where the burden ratio becomes light increases, and the opening/closing direction becomes tight in the direction in which the support loosens, so the opening/closing side , the load sharing tends to converge to 50:50. The converged position is the gripping position GG.
At the time of lowering, for example, if the share of the support motor HM is to be increased, the speed of the support increases, the speed on the opening/closing side where the load ratio is lightened decreases, and the opening/closing rope GW is pulled in the direction in which the support rope HW loosens. Since it is in the tension direction, the load sharing tends to return to the opening/closing side, and the load sharing tends to converge to 50:50. Again, the converged position is the gripping position GG.
In this way, by adopting the characteristics shown in FIG. 7, it tries to positively converge to the state of the gripping position GG in FIG. The grasping end position is maintained without spilling the object and without overloading the opening/closing motor GM in the state shown in FIG. 5(4).

The weight ratio between the weight of the bucket GB and the bulk cargo HO is that, in the case of ore with a large specific gravity, the weight of the bucket GB and the weight of the bulk cargo HO when it is fully gripped (rated capacity) are the same weight. In many cases, the weight of the loose cargo HO is about 60% to 30% of the weight of the bucket GB, such as wood chips, grains, combustible waste, etc., which have a light specific gravity. It is common to be a load value.
When ore with a heavy specific gravity is picked up by a lightweight bucket, the weight of the bulk cargo HO may be heavier than the weight of the bucket GB, but this is a rare case.

When the weight of the bucket GB and the weight of the bulk cargo HO when it is full (rated capacity) are the same, the load of the support motor HM in FIG. 5 (1) and the support motor HM in FIG. 5 (3) open and close. The load value of the motor GM is equal and becomes the maximum load. Therefore, it is economical to set the value of this load to the rated output of the support motor HM and the open/close motor GM, and generally designed in such a manner. However, even in this case, it is rare for the bulk cargo to be fully gripped, and usually only about 60 to 80% of the cargo is gripped. Generally, there is excess power.
In the case of a bucket that grips loose cargo with a light specific gravity, the weight of the bulk cargo HO when fully gripped is lighter than the load of the bucket GB, so the support motor HM in (1) of FIG. 5 becomes the maximum load. , this state is used as the rated output of the support motor HM, and the open/close motor GM is designed to match it. In this case, in the state of (3) in FIG. 5, a surplus power is generated in the outputs of the support motor HM and the open/close motor GB. In addition, since it is usually not possible to grasp the entire container, and only about 60 to 80% of the container can be grasped, a surplus power is generated in the motor output in the state of (3) in FIG.
In the case of a lightweight bucket that grips an object with a heavy specific gravity, the load applied to the support motor HM and the open/close motor GM reaches its maximum load when the loose cargo HO is fully gripped in the state of (3) in FIG. is the rated output of the support motor HM and the opening/closing motor GM.
When such a lightweight bucket is used, it is difficult to fully grip it due to the principle of a double rope type bucket that exerts a gripping force with the own weight of the bucket GB, and the weight of the loose cargo HO that can be gripped is reduced to about 50%. In many cases, it stays, and in the state of (3) in FIG. 5, the output power of the support motor HM and the open/close motor GM is generated.

The characteristics of FIG. 7 used in the gripped state of FIG. Easier to balance. However, with the characteristics of FIG. 7, the winding speed becomes slower than the rated speed. As a result, the rated speed of the crane hoisting becomes insufficient and the performance against the performance display value cannot be maintained. , the amount by which the actual speed ω is delayed from the speed target value ω ^* is added to the speed target values ω ^* of the support motor HM and the opening/closing motor GM, thereby compensating for the delay.

In addition, when the value of the torque T when the torques T of the support motor HM and the opening/closing motor GM are balanced has a surplus with respect to the rated torque of the supporting motor HM and the opening/closing motor GM, Then, the speed target value ω ^* of the support motor HM and the open/close motor GM is increased to the maximum speed that can be output with respect to the surplus power, thereby increasing the winding speed and shortening the transport time.

In the characteristics of Fig. 7 used in the state of gripping position GG in Fig. 5 (3), the speed on the lowering speed side (negative torque side) exceeds the rating and is output, A small speed increase (8% in the example) is not a problem in motor capacity, as the mechanical losses help the motor output.
When the torque T of the support motor HM and the opening/closing motor GM is balanced during hoisting as well as during hoisting, it is possible to increase the speed by the amount of motor surplus power. , there is almost no lowering operation in the gripped state, and there are few opportunities to make use of that ability.

The characteristics shown in FIG. 6 are set when the bucket GB is not gripped (the open/closed position on the open side of the closed deceleration position GCD), and the state when the bucket GB is gripped (the open/closed position on the closed side of the closed deceleration position GCD). FIG. 8 shows a control block diagram of a speed control system for realizing the characteristics shown in FIG. In this control block diagram, the target speed value ω ^* is the value of ω when the torque T in the characteristic diagram of FIG. 6 or 7 is zero. Then, the speed deviation amount obtained by subtracting the actually output speed ω detected by the speed detector PG from the speed target value ω ^* is input to the automatic speed setter ASR.
When realizing the characteristics shown in FIG. 6, the automatic speed setter ASR is set to the proportional integral characteristic PIC, the speed deviation amount is accumulated in the integrator, and the torque is controlled until the integral is released. 6, a characteristic that there is no speed deviation with respect to the torque T shown in FIG. However, since it is accumulated in the integrator only after the amount of speed deviation occurs, a slight steady-state deviation occurs. After passing through the automatic speed setter ASR, the torque is passed through the torque limiter LM to obtain the torque target value T ^* .
In order to realize the characteristics shown in FIG. 7, the automatic speed setting device ASR for inputting the speed deviation amount is assumed to be the proportional characteristic PC. It outputs a proportional torque and generates a torque target value T ^* after passing through a torque limiter LM. As a result, the characteristics shown in FIG. 7 are obtained, in which the output speed is slowed down in proportion to the magnitude of the load during hoisting, and the speed is increased in proportion to the magnitude of the load in hoisting down.

Here, switching between the characteristics in FIG. 6 when the bucket GB is not gripped and the characteristics in FIG. Switching is performed between the closing side from the deceleration position GCD and the opening side from the closing deceleration position GCD, and the switching of the control characteristics shown in FIGS. 6 and 7 is not performed during motor operation. This is in consideration of the occurrence of a switching shock at the time of switching.
For example, even if the closed deceleration position GCD is switched after the motor starts to move in either of FIG. 6 or FIG.

The closing deceleration position GCD is used to switch the control characteristics of FIG. 6 and FIG. At the GCD position, the bulk cargo HO cannot be held in the bucket, and from this position on the open side, the bucket GB is a single unit, and the load sharing between support and opening is at the position of (2) in FIG. , the closed deceleration position GCD and the control switching position are the same optimum position (in the embodiment, the position where the open/close rope GW is 0.6 m on the open side from the closed end position GC), so the closed deceleration position GCD is used as the control switching position. ing.
At this time, if the hoisting or hoisting is performed from the closed deceleration position GCD with the characteristics shown in FIG. 7, the hoist moves quickly to the gripping position GG, and the load sharing between the support motor HM and the open/close motor GM converges to 50:50.
When the gripping position GG is slightly opened, the grasping force for gripping the loose cargo HO is lost, and the bulk cargo HO drops from the gap between the shells CL. The GB is empty.

When the characteristics shown in FIG. 6 are assumed on the opening side of the closed deceleration position GCD, the characteristics shown in FIG. end up trying. However, at the closed deceleration position GCD, only the load of the bucket GB alone is applied, so the load supported by the support motor HM is 100% or less, and the load of the support motor HM cannot exceed 100% and become overloaded. do not have.
Further, at the position on the closing side from the closing deceleration position GCD, the opening/closing rope GW is further tightened up to the closed end position GC from the opening/closing position of the gripping position GG where the opening/closing is restrained due to the loose cargo caught between the shells CL. As shown in FIG. 5(4), the support rope HW becomes slack, and the weight of the bucket GB and the weight of the bulk cargo HO are all applied only to the opening/closing rope GW, and the opening/closing becomes overloaded. However, on the closing side of the closed deceleration position GCD, the control characteristics are as shown in FIG. Since the gripping position GG at 50 is quickly converged and maintained, the state shown in FIG.

As for the transport pattern of the crane CR with a bucket, it is common to grab the loose cargo HO below the pit PT and open it above the hopper HOP and the like, as shown in the layout shown in FIG. And the conveying pattern of gripping at the top and opening at the bottom is not common.
In an operation example other than that shown in FIG. 9, for example, an unloader grabs the cargo in the lower cargo hold and opens it with the upper hopper HOP. Dredging buckets also grip the riverbed or seabed below the water surface and open to barges or land above the water surface. In the case of an operational example in which the unloading truck is the opening location, the unloading truck is located above the gripping position.
In this way, the transport pattern of the crane with a bucket is such that the loose cargo HO is gripped during hoisting, and the bucket GB is not gripped during hoisting, and the bucket GB is at the open end position GO. It will be in a state to go grab it.

In the process of lowering while being gripped in the transport pattern of a crane with a bucket, there is a shock that the loose cargo HO scatters on the hopper HOP or on the carry-out truck, or the bulk cargo HO falls. In order to alleviate the problem, the bucket GB may be lowered at a low speed while being gripped on the hopper HOP or on the unloading truck.
In the transport pattern with the bucket open, there is a process of transporting the bucket to the bucket storage area to stop the bucket, except for the work of grabbing the loose cargo HO with the bucket GB fully opened at the open end position GO. , even when the bucket GB is on standby, it is sufficient if the state of the open end position GO, in which the bucket is most stable and the claw TA is least damaged, can be secured.
In this way, in the crane with a bucket, only two points, the gripping position GG and the open end position GO, are open/closed states required for transportation, and the other open/closed intermediate positions are not necessary for transportation. There is no need to hold the state of the intermediate position between opening and closing, because the state is only a transitional state. Therefore, the state of the open end position GO is positively created in the non-grasping state.

When the bucket GB is opened on the hopper HOP, if the bucket GB is opened vigorously, as shown in FIG. A bridge BRI phenomenon may occur in which the hopper HOP becomes non-functional due to the loose cargo HO becoming clogged inside. This phenomenon is caused by the properties of the bulk cargo HO and how the bucket GB is opened. In order to prevent this bridge BRI phenomenon, there is a method of opening the bucket GB slightly at the edge of the hopper HOP and gradually dropping the gripped loose cargo HO, as shown in FIG. 9(1). This method has the effect of preventing scattering of dust, and the effect of softening the impact on the truck when loading onto the unloading truck.
After dropping the bulk cargo HO in the bucket GB by this opening method of the bucket GB, even if it enters the area above the pit PT where it can be lowered while performing the traversing or traveling operation TS and the opening of the bucket GB at the same time. , has not yet reached the open end position GO.
In the present invention, instead of waiting for the lowering operation until the open end position is reached, the lowering operation is performed in the state of the bucket open/close position on the open side of the closed deceleration position GCD even if the open end position GO is not reached. , by outputting the speed of the opening/closing motor GM exceeding the rated speed and increasing the speed of the opening/closing motor GM from that of the support motor HM with a speed difference, the winding is lowered in the flow of (1) to (4) in FIG. It is possible to increase the efficiency of conveying by opening while moving.

The situation of the conveying pattern in which the bucket is lowered while the bucket is at the open/closed position on the open side of the closed deceleration position GCD is either the situation of grabbing the bucket or the situation of moving to the bucket maintenance position. situation. As for the load sharing between the support motor HM and the opening/closing motor GM at this time, since the load sharing of the opening/closing motor GM is small as shown in (2) of FIG. I have the power to put it out.
Then, the speed target value ω ^* of the open/close motor GM is raised from the support motor HM to move toward the open end position GO, and control is performed to maintain the open end position GO. can completely eliminate the phenomenon that the bucket GB closes due to the influence of

As for the opening/closing speed at this time, since the opening/closing load torque is less than 15%, the speed of the opening/closing motor GM can be increased to 200%. When the lowering operation is stopped after that, the deceleration distance of the opening and closing rope GW (4.8 m in the embodiment) is quadrupled relative to the deceleration distance of the support rope HW (1.2 m in the embodiment), and the relative deceleration between the support and the opening and closing. The distance is tripled (3.6 m in the embodiment), and if the hoisting is stopped in this state, the opening/closing rope GW is extended greatly.
In order to prevent this, the speed of the open/close motor GM is suppressed to 2 ^1/2 times that of the support motor, and the deceleration distance of the open/close rope GW is set to twice the deceleration distance of the support rope HW, and the relative deceleration distance is suppressed to 1 time. .
When both the support motor HM and the opening/closing motor GM are decelerated and stopped at the same time in a state in which the speed of the opening/closing motor GM is increased more than that of the support motor HM by simultaneously lowering and opening, the deceleration distance increases by the square of the speed difference. Since the opening/closing rope GW is extended greatly, the speed of the opening/closing motor GM should be suppressed to 2 ^1/2 without increasing it too much. However, by increasing the speed of the open/close motor GM rather than the support motor HM, the speed of the open/close motor GM is made equal to the speed of the support motor HM and the open/close motor GM from a state in which the speed of the open/close motor GM is increased and the winding operation is stopped. Since the opening/closing deceleration distance when the lowering is continued becomes the normal deceleration distance, if the opening/closing speed is suppressed so as not to be excessive, the opening/closing time takes time.

As shown in FIG. 9, the speed of the open/close motor GM is set to 2 ^1/2 times the speed of the support motor HM, and the speed of the open/close motor GM is set to 2 1/2 times the speed of the support motor HM. , the speed of the open/close motor GM is decelerated to be slightly higher than the support speed, and when the open end position GO is reached while maintaining that speed, the support speed and the open/close speed are made equal.
In this way, the speed difference between the support speed and the opening/closing speed is kept small, and the lowering is performed while opening slowly. Because there is not, it takes time to open. At this time, the relative distance between the support and opening/closing to the open end position GO is grasped numerically instead of controlling only the two points of the open deceleration position GOD and the open end position GO. If the speed difference is controlled linearly while calculating the maximum relative speed that can be output for that relative distance, it is possible to produce a speed difference of 2 ^1/2 times or more, and the opening time during lowering can be shortened. At the same time, it is possible to improve the ability to maintain the position of the open end position GO after reaching the position of the open end position GO.

By the way, in order to simultaneously perform the winding operation and the opening operation, there is a method of increasing the speed of the support motor HM or decreasing the speed of the opening/closing motor GM. The support motor does not have the capacity to increase the speed beyond the rated speed, and the method of opening the opening/closing motor GM by slowing it down does not contribute to shortening the transport time. In addition, the situation in which the bucket GB must be opened by hoisting it upward is a rare case in the transport pattern, so the method of opening while hoisting is not a very important function.

Although the method for controlling the hoisting and lowering of a crane with a double-rope bucket according to the present invention has been described above based on the embodiment, the present invention is not limited to the configuration described in the above embodiment. The configuration can be changed as appropriate within a range that does not deviate from the above.

The method of controlling the hoisting and lowering of a crane with a double rope type bucket according to the present invention optimizes the control of the support motor and the opening/closing motor according to the state of the bucket, and optimizes the load sharing between the support and the opening/closing to prevent motor overload. It is possible to reduce troubles due to rope slackness, to control it easily without rope slack, to make the movement consistent with the transportation process, and to improve the transportation efficiency, so that it can be suitably used in a crane with a double rope type bucket.

CR Crane HD Support drum GD Opening and closing drum HM Support motor GM Opening and closing motor BR Brake GR Reduction gear LC Load cell HP Support position detector GP Opening and closing position detector PG Speed detector HW Support rope GW Opening and closing rope GB Bucket HB Upper sheave box LL Connecting rod CL Shell TA Claw BB Lower sheave box HS Upper sheave pin BS Lower sheave pin SH Sheave CS Cotter sheave GO Open end position GOD Open deceleration position GCD Close deceleration position GC Closed end position GG Grip position HT Support torque GT Open/close torque ω Speed T Torque ω ^* Speed Target value T ^* Torque target value ASR Automatic speed setting device PC/PIC Proportional characteristic/Proportional integral characteristic LM Torque limiter PT Pit HO Bulk cargo HOP Hopper BRI Bridge TS Traversing or traveling movement HR Support lowering movement GR Open/close lowering movement

Claims (2)

A method for controlling the hoisting and lowering of a crane with a double-rope bucket for controlling the hoisting and lowering of a double-rope bucket with two types of equal-capacity hoisting devices that are independent of a support motor and an opening/closing motor, comprising:
When the opening/closing state of the bucket is on the closing side from the vicinity of the bucket closing deceleration position, the output speed of the support motor and the opening/closing motor during hoisting is proportional to the magnitude of the load as the magnitude of the load increases. control to slow down, and when lowering, control to speed up in proportion to the size of the load as the size of the load increases,
When the open/closed state of the bucket is on the open side from the vicinity of the closed deceleration position of the bucket, the speed deviation is controlled to be small regardless of the magnitude of the load during hoisting and lowering, and the open/close motor is controlled during hoisting and lowering. By expanding the speed control range to a range exceeding the rated speed, and making the speed of the opening/closing motor faster than that of the support motor, the bucket opens while being lowered. A method for controlling the hoisting and lowering of a crane with a double rope type bucket, characterized in that the hoisting and lowering is performed while maintaining the state of the open end position by equalizing . When the opening/closing state of the bucket is on the closing side from the vicinity of the closing deceleration position of the bucket, when the speed or torque of the support motor and the opening/closing motor after the end of acceleration become equal, there is a surplus motor torque. The control method for hoisting and lowering of a crane with a double rope type bucket according to claim 1, characterized in that the speed is increased to the maximum speed that each motor can output according to the size of the load at that time. .

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