CN114148901A - Gantry crane grab bucket grabbing amount control system and control method thereof - Google Patents

Abstract

The invention discloses a gantry grab bucket grabbing amount control system and a corresponding control method thereof, wherein the system comprises a support mechanism position sensor, an opening and closing mechanism position sensor, a support mechanism speed encoder, an opening and closing mechanism speed encoder, a PLC (programmable logic controller) and an operation panel, wherein the operation panel is provided with a display screen, a material selection knob, a deep digging adjusting knob, a deep digging starting button and an automatic grabbing starting button; the gantry crane grab control method is realized based on a gantry crane grab grabbing amount control system; the gantry crane grab bucket grabbing amount control system and the corresponding control method thereof can effectively improve the operation efficiency of loading and unloading goods with higher specific gravity, simultaneously avoid the damage to the gantry crane due to overload and ensure the safety of a human machine; meanwhile, the system is simple to operate, reduces the requirement on the operation level of a door phone driver, lightens the labor intensity of the driver, and objectively reduces the risk of accidents.

Description

Gantry crane grab bucket grabbing amount control system and control method thereof

Technical Field

The invention relates to the field of loading and unloading operation of wharfs, in particular to a system and a method for controlling the grabbing amount of a gantry grab bucket.

Background

At present, the rated lifting capacity of a common gantry crane in the wharf unloading operation is 40t, the specific gravity of unloaded goods is various and basically ranges from 1.9 to 2.8, but grab buckets with different sizes are stored to adapt to materials with different specific gravities, so that the cost is high, and time and labor are consumed when the grab buckets are replaced. Therefore, although a light grab bucket with a large bucket capacity and a grab bucket with a small bucket capacity are generally adopted at the loading and unloading site at present, the production operation efficiency of the grab buckets with different capacities for loading and unloading goods with different specific gravities shows obvious difference.

Generally, the loading and unloading efficiency of the goods with lower loading and unloading specific gravity is higher, because when the goods with lower loading and unloading specific gravity are loaded and unloaded, a light grab bucket with large bucket capacity is usually selected; when the goods are grabbed, the weight of the full bucket is basically below 40t, so that the operation technical requirements on a door machine driver are low; the operation efficiency of a driver with a relatively high operation level is not much different from that of a driver with a relatively low operation level; when the goods with higher specific gravity are loaded and unloaded, the grab bucket with small bucket capacity is selected, so that the weight of the grab bucket cannot reach 40t even if the grab bucket is full of the goods, and the operation capacity of the gantry crane is wasted; when the grab bucket with a large bucket capacity is selected for grabbing, the total weight of the grab bucket when the grab bucket is fully loaded exceeds the maximum operation load of the gantry crane, so that the overload phenomenon is caused, and a driver of the gantry crane can only reopen the grab bucket to cause partial goods to leak out, and then reopens the grab bucket. This process of re-opening and re-closing the bucket causes a waste of time and reduces the operating efficiency. However, a driver of the portal crane with high operation level can manually control the grabbing amount of the grab bucket according to the closing degree of the grab bucket in the grabbing process and the weight display in the cab, so that the grabbing amount is basically kept at 40t, the process of re-opening and re-closing the grab bucket is avoided, and the operation efficiency is ensured; therefore, the goods with higher loading and unloading specific gravity have higher operating technical requirements on the driver of the portal crane, the operating efficiency of the driver with higher operating level is higher than that of the driver with lower operating level, but the portal crane drivers with high operating level are few, and each driver cannot reach a high level.

In summary, in order to improve the work efficiency when the goods with high specific gravity are loaded and unloaded, a device which can be used in cooperation with the operation of the grab bucket and effectively improve the work efficiency when the goods with high specific gravity are loaded and unloaded needs to be developed from the control of the grab bucket.

Disclosure of Invention

The invention aims to provide a gantry crane grab bucket grabbing amount control system for improving the operation efficiency of loading and unloading goods with high specific gravity.

The invention also aims to provide a control method realized based on the gantry crane grab bucket grabbing amount control system.

Therefore, the technical scheme of the invention is as follows:

a gantry grab bucket pick-up control system, comprising:

a) a support mechanism position sensor installed on a rotation mechanism of a hoist of the support mechanism to collect a rotation position signal of a motor driving shaft of the hoist of the support mechanism;

b) an opening and closing mechanism position sensor which is arranged on a rotating mechanism of a winding engine of the opening and closing mechanism so as to collect a rotating position signal of a motor driving shaft of the winding engine of the opening and closing mechanism;

c) the support mechanism speed encoder is arranged on a motor driving shaft of a winch of the support mechanism so as to acquire a rotating speed signal of the motor driving shaft of the winch of the support mechanism;

d) the opening and closing mechanism speed encoder is arranged on a motor driving shaft of a winch of the opening and closing mechanism so as to detect a rotating speed signal of the motor driving shaft of the winch of the opening and closing mechanism;

e) a PLC controller arranged in a control box arranged on the side surface of the linkage table in the cab of the door machine; the PLC is respectively and electrically connected with a support mechanism position sensor and a switching mechanism displacement sensor, and the PLC is respectively and electrically connected with a support mechanism speed encoder and a switching mechanism speed encoder; the PLC controller is electrically connected with a winch of the supporting mechanism through a frequency converter A, the PLC controller is electrically connected with a winch of the opening and closing mechanism through a frequency converter B, and the PLC controller is electrically connected with an overload system which is arranged in a matched manner with the grab bucket per se; and

f) an operation panel provided on an upper surface of the control box; the operation panel is provided with a display screen electrically connected with the PLC, a material selection knob electrically connected with the PLC through a digital quantity input module, a deep digging adjustment knob connected with the PLC through an analog quantity input module, a deep digging start button electrically connected with the PLC, and an automatic grabbing start button electrically connected with the PLC; the deep digging adjusting knob adopts an electrodeless knob.

Further, the supporting mechanism position sensor and the opening and closing mechanism position sensor may be hall sensors, which are mounted on the motor rotor assembly.

Furthermore, an upper display frame and a lower display frame are arranged on the display device; the upper display frame is used for displaying the numerical value corresponding to the current gear of the material selection knob; and the lower display frame is used for displaying the numerical value corresponding to the current position of the deep-digging adjusting knob.

A gantry crane grab bucket control method based on the gantry crane grab bucket grabbing amount control system comprises the following steps:

determining an appropriate opening angle of a grab bucket corresponding to a material to be grabbed:

step 1: rotating a material selection knob to a gear matched with the material, and starting a deep digging start button; a deep digging starting button sends a grabbing signal to a PLC controller, and the PLC controller controls a winch motor driving shaft of a supporting mechanism to continuously rotate in the forward direction until the PLC controller acquires that the weight value of the grab bucket transmitted by an overload system is 0; meanwhile, the material selection knob inputs an appointed signal to the PLC, the PLC controls a driving shaft of a winch motor of the opening and closing mechanism to rotate forwards for an appointed number of turns according to the appointed signal, and then the closed steel wire rope is released to an appointed length, so that the grab bucket is opened to an appointed opening angle;

step 2: the grab bucket grabs the material at a specified opening angle and lifts the material away from the material surface, and whether the grabbing reaches the maximum operation capacity of the gantry crane or not is judged according to the grab bucket weight value displayed by the overload system in real time;

and step 3: if the weight value of the grab bucket does not reach or exceed the maximum operation capacity of the gantry crane in the step 2, adjusting the number of rotation turns of a driving shaft of a winch motor of the opening and closing mechanism by adjusting a deep digging adjusting knob so as to finely adjust the specified opening angle of the grab bucket; starting the deep-digging starting button again, sending a grabbing signal to the PLC by the deep-digging starting button, and controlling the winch motor driving shaft of the supporting mechanism to continuously rotate in the forward direction by the PLC until the weight value of the grab bucket transmitted by the overload system is collected by the PLC to be 0; meanwhile, a specified signal is input into the PLC by the deep digging adjusting knob, the PLC controls a driving shaft of a winch motor of the opening and closing mechanism to rotate forward for a specified number of turns according to the specified signal, and then the closed steel wire rope is released to a specified length, so that the grab bucket is opened to a new specified opening angle;

repeating the step 2 to the step 3, wherein the specified opening angle of the grab bucket meets the requirement that the material grabbing amount reaches the maximum operation capacity of the gantry crane; the corresponding numerical value of the deep digging adjusting knob is the optimal adjusting value;

and (II) finishing all material grabbing in an automatic grabbing manner based on the opening angle determined in the step (I):

keeping the deep digging adjusting knob at the optimal adjusting value, and starting an automatic grabbing starting button; an automatic grabbing start button inputs an automatic grabbing operation signal to the PLC;

the PLC controller controls a winch motor driving shaft of the supporting mechanism to continuously rotate in the forward direction, meanwhile, a deep digging adjusting knob inputs a designated signal to the PLC controller, the PLC controller controls the winch motor driving shaft of the opening and closing mechanism to rotate in the forward direction for a designated number of turns, a closed steel wire rope is released for a designated length below the designated number of turns, and the grab bucket is opened to a designated opening angle in the descending process;

when the PLC acquires that the weight value of the grab bucket detected by the overload system is 0, the PLC controls a motor driving shaft of a winch of the opening and closing mechanism to rotate reversely for a specified number of turns, the opening and closing steel wire rope is pulled up and tightened to a specified length, the grab bucket is closed, and the grabbing of the material is completed;

when the PLC acquires that the rotating speed input by the speed encoder of the opening and closing mechanism is 0, the PLC controls a winding motor driving shaft of the supporting mechanism to continuously rotate in the reverse direction, the supporting steel wire ropes are lifted and tightened, when the numerical difference transmitted by the displacement sensor of the opening and closing mechanism and the displacement sensor of the supporting mechanism is 0, the rope difference between the two opening and closing steel wire ropes and the two supporting steel wire ropes is 0, the grab bucket leaves the material slowly at the moment, the grabbing action is finished, and the rotating bucket can be controlled to be transferred to a target position for unloading;

in the process of the step (I) and the step (II), the PLC calculates whether the rope difference between the support steel wire rope and the opening and closing steel wire rope exceeds a set threshold value according to position signals input by the support mechanism position sensor and the opening and closing mechanism position sensor so as to judge whether the steel wire rope is in a loose state; when the PLC calculates that the rope difference exceeds a set threshold value, the rotating speed of a motor driving shaft of the supporting mechanism winch or the rotating speed of a motor driving shaft of the opening and closing mechanism winch is controlled to be adjusted according to the current movement speeds of the supporting steel wire rope and the opening and closing steel wire rope collected by the speed encoder of the supporting mechanism and the speed encoder of the opening and closing mechanism.

Compared with the prior art, the gantry crane grab bucket grabbing amount control system and the corresponding control method thereof can effectively improve the operation efficiency of loading and unloading goods with higher specific gravity, simultaneously avoid the damage to the gantry crane due to overload and ensure the safety of a human machine; meanwhile, the system is simple to operate, reduces the requirement on the operation level of a door phone driver, lightens the labor intensity of the driver, and objectively reduces the risk of accidents.

Drawings

FIG. 1 is a schematic structural diagram of a gantry crane grab bucket grabbing amount control system of the present invention;

fig. 2 is a front view of an operation panel of the gantry crane grapple grab control system of the present invention.

Detailed Description

The invention will be further described with reference to the following figures and specific examples, which are not intended to limit the invention in any way.

The gantry crane grab bucket grabbing amount control system is suitable for four-rope grab buckets; the four-rope grab bucket mainly comprises an upper cross beam, a pull rod, a lower cross beam and a bucket part, and is matched with a bridge crane for use so as to grab various bulk cargos and carry out operations such as loading, unloading, turning and piling; the crane hoisting system is provided with a front hoisting mechanism and a rear hoisting mechanism, wherein the front hoisting mechanism is simply called as an opening and closing mechanism, and the rear hoisting mechanism is simply called as a supporting mechanism; the rear hoisting mechanism consists of a hoisting motor and a set of steel wire rope reel system, one ends of two supporting steel wire ropes are led out from the steel wire rope reels, and the other ends of the two supporting steel wire ropes are symmetrically fixed at two ends of a balance beam of the grab bucket to play a supporting role; the front hoisting mechanism is also composed of a hoisting motor and a set of wire rope reel system, one end of each of two opening and closing wire ropes is led out from the front wire rope reel, and the other end of each of the two opening and closing wire ropes is respectively wound on a pulley positioned below the middle of the cross beam and a lower pulley positioned on the upper side of the bucket petal to form a pulley block;

the four-rope grab bucket has the following operation principle: synchronously lowering the opening and closing steel wire rope through the front winches to enable the dead weight of the lower cross beam to force the large shaft of the cross beam below the bucket to be opened to a proper angle, and lowering the grab bucket to a position with the grab material by controlling the two winches to synchronously lower and support the steel wire rope; the opening and closing mechanism is controlled to lift to tighten and open the steel wire ropes to complete grabbing and taking, the grab bucket is closed, materials are filled in the closed hopper, then the supporting steel wire ropes are synchronously tightened by controlling the supporting winch until the four steel wire ropes are in a uniform stress state, two hoisting mechanisms are recently controlled to simultaneously act to lift the grab bucket to a safe height, and then the grab bucket moves to a required unloading field to unload the materials.

In the process, the grabbing amount of the material is different based on the grab bucket which exists in the current operation process at every time, and the problem that the grabbing efficiency is low and the like generally exists for the material with high specific gravity is solved, and a set of gantry crane grab bucket grabbing amount control system capable of effectively improving the operation efficiency is additionally arranged.

As shown in fig. 1, the door grapple grabbing amount control system comprises a support mechanism position sensor, an opening and closing mechanism position sensor, a support mechanism speed encoder, an opening and closing mechanism speed encoder, an operation panel and a PLC controller; wherein the content of the first and second substances,

the support mechanism position sensor is arranged on a rotating mechanism of a winch of the support mechanism to acquire a rotating position signal of a motor driving shaft of the winch of the support mechanism, and further determine the number of forward or reverse rotating turns of the motor driving shaft to obtain the lowering length or the tightening length of the support steel wire rope;

the opening and closing mechanism position sensor is arranged on a rotating mechanism of a winch of the opening and closing mechanism to acquire a rotating position signal of a motor driving shaft of the winch of the opening and closing mechanism so as to determine the number of forward or reverse rotating turns of the motor driving shaft and further obtain the lowering length or the tightening length of the opening and closing steel wire rope;

specifically, a Hall sensor can be selected as the support mechanism position sensor and the opening and closing mechanism position sensor, the Hall sensors are arranged on the motor rotor assembly, and the rotating position signal of the motor driving shaft is determined according to the rotating Hall sector value of the Hall sensor so as to convert the forward or reverse rotating turns of the motor rotating shaft;

the support mechanism speed encoder is arranged on a motor driving shaft of a winch of the support mechanism so as to acquire a rotating speed signal of the motor driving shaft of the winch of the support mechanism;

the opening and closing mechanism speed encoder is arranged on a motor driving shaft of a winch of the opening and closing mechanism so as to detect a rotating speed signal of the motor driving shaft of the winch of the opening and closing mechanism;

a control box is arranged on the side surface of a linkage table in a cab of the portal crane, a PLC controller is arranged in the control box, and an operation panel is arranged on the upper surface of the control box;

the PLC is electrically connected with the position sensor of the supporting mechanism so as to obtain a rotating position signal of a motor driving shaft of a winch of the supporting mechanism and further obtain the lowering length or the tightening length of the supporting steel wire rope;

the PLC is electrically connected with the displacement sensor of the opening and closing mechanism to obtain the rotation position signal of the motor driving shaft of the winch of the opening and closing mechanism, and further obtain the lowering length or the tightening length of the opening and closing steel wire rope

The PLC is electrically connected with the speed encoder of the supporting mechanism so as to obtain a rotating speed signal of a motor driving shaft of a winch of the supporting mechanism;

the PLC is electrically connected with the speed encoder of the opening and closing mechanism so as to obtain a rotating speed signal of a motor driving shaft of a winch of the opening and closing mechanism;

the PLC is electrically connected with a winch of the supporting mechanism through the frequency converter A so as to control the rotating speed of a winch motor driving shaft of the supporting mechanism through the PLC, and further when the PLC detects that the supporting steel wire rope is too much loosened due to rope difference relative to the opening and closing steel wire rope, the PLC controls the lowering speed or the lifting and tightening speed of the supporting steel wire rope so as to reduce the rope difference;

the PLC is electrically connected with a winch of the opening and closing mechanism through the frequency converter B so as to control the rotating speed of a winch motor driving shaft of the opening and closing mechanism through the PLC, and further when the PLC detects that the opening and closing steel wire rope is too much loosened relative to the supporting steel wire rope due to the rope difference, the PLC controls the lowering speed or the lifting tightening speed of the opening and closing steel wire rope so as to reduce the rope difference;

the PLC is electrically connected with an overload system which is arranged in a matched manner with the grab bucket to obtain a grab bucket weight value measured by the overload system;

as shown in fig. 2, the operation panel is provided with a display screen, a material selection knob, a deep-digging adjustment knob, a deep-digging start button and an automatic grabbing start button; in particular, the amount of the solvent to be used,

the material selection knob is connected with the PLC through a digital input module; specifically, N gears are arranged on a material selection knob at intervals in the circumferential direction, the number N of the gears is consistent with the number of types of materials with different specific gravities in actual operation of a company, each gear corresponds to one type of material, when the material selection knob rotates to a specified gear, a specified signal is output to a PLC (programmable logic controller), the PLC controls the forward rotation of a winch motor driving shaft of an opening and closing mechanism to a specified number of turns, so that the opening and closing of a steel wire rope is lowered to a specified length, and a grab bucket is opened to a specified opening angle according to the known material types;

the specified opening angle is an appropriate opening angle determined according to the conventional specific gravity of the materials, but in the actual operation process, the actual specific gravity of the materials has larger difference due to different purities;

in this embodiment, the applicant sets 4 shift positions FOR the material selection knob according to the goods that the applicant mainly handles are yandi powder, PB powder, FOR powder and brazil powder, and sets four reference adjustment values according to the operation experience and the specific gravity difference of the four materials, as shown in table 1 below.

Table 1:

goods and their use	Specific gravity of	Reference regulation value
			Yangdi powder	1.9	5
PB powder	2.1	4.4
			FOR powder	2.27	3.5
Brazil powder	2.56	2.3

The deep digging adjusting knob is an electrodeless knob and is connected with the PLC through an analog quantity input module to output an appointed signal to the PLC, so that the PLC controls the forward rotation appointed number of turns or the reverse rotation appointed number of turns of a winch motor driving shaft of the opening and closing mechanism to realize the downward movement of the opening and closing steel wire rope to an appointed length or the upward movement of the opening and closing steel wire rope to an appointed length, the adjustment of the number of turns of the winch motor driving shaft is completed, and the opening angle of the grab bucket is further adjusted; specifically, when the stepless knob is arranged, the corresponding scale range of one circle of rotation is 0-9, the opening angle (namely the opening angle between two bucket petals) of the corresponding grab bucket is 0-180 degrees, the stepless knob can be used for realizing any micro adjustment of the opening angle of the grab bucket, and the grab bucket is adjusted to a proper opening angle from a specified opening angle; when the corresponding scale value of the deep-digging adjusting knob is 0, the position of the deep-digging adjusting knob is a neutral gear;

it should be noted that the suitable opening angle means that after the grab bucket grabs and closes the material at the current opening angle, the material grabbing amount in the grab bucket is 40t and is adapted to the maximum operation load of the gantry crane; in addition, for the similar cargos in different batches, the specific gravity value of the similar cargos has larger deviation which is not suitable for estimation due to the problem of purity, so that on the basis of a theoretical adjustment value, a driver of a portal crane is required to correspondingly adjust the proper opening angle of the grab bucket in the grabbing operation process according to the actual specific gravity of the current cargo;

the deep digging starting button is electrically connected with the PLC, and outputs an electric signal to the PLC when the deep digging starting button is opened, so that the PLC controls a motor driving shaft of a winch of the supporting mechanism to rotate to lower the supporting steel wire rope according to a specified signal output by the material selecting knob or the deep digging adjusting knob, the grab bucket is lowered to the surface of a material to be grabbed, and meanwhile, the PLC controls the motor driving shaft of the winch of the opening and closing mechanism to rotate to release the closed steel wire rope until the grab bucket is opened to a specified opening angle; when the PLC is set, when the adjusting value of the deep-digging adjusting knob is 0, the appointed opening angle is determined by the current gear of the material selecting knob, and when the adjusting value of the deep-digging adjusting knob is not 0, the appointed opening angle is determined by the deep-digging adjusting knob; when the material surface is lowered to be grabbed, the deep digging starting button is automatically closed;

the automatic grabbing starting button is connected with the PLC through a data transmission line and is used for starting and closing the automatic grabbing action of the grab bucket; specifically, when the automatic grabbing start button is started, the PLC controller executes an automatic grabbing action once, and the process is as follows: the PLC controls a winch motor driving shaft of the supporting mechanism to rotate so as to lower the supporting steel wire rope, so that the grab bucket gradually descends to the surface of the material to be grabbed, and meanwhile, the PLC controls the winch motor driving shaft of the opening and closing mechanism to rotate so as to release the closed steel wire rope until the grab bucket is opened to the current specified adjusting value of the deep digging adjusting knob to correspondingly specify the opening angle; when the grab bucket descends to the surface of a material to be grabbed, the PLC controls a winch motor driving shaft of the opening and closing mechanism to rotate so as to lift and tighten the opening and closing steel wire rope until the grab bucket is completely closed, at the moment, the material grabbing is completed, and the PLC controls a winch motor driving shaft of the supporting mechanism to rotate so as to lift and tighten the supporting steel wire rope until the opening and closing steel wire rope and the two steel wire ropes recover the original cordless difference state; at the moment, the grabbing action is finished, the grab bucket lifts the material to a safe height, and the automatic grabbing start button is automatically closed; when the automatic grabbing start button is closed, the material grabbing action is completed by a driver in a cab of the portal crane through manual operation;

the display screen is electrically connected with the PLC and is provided with an upper display frame and a lower display frame; the upper display frame is used for displaying a ground reference adjusting value corresponding to the current gear of the material selection knob so as to be referred by a driver of the door machine; and the lower display frame is used for displaying the actual regulating value corresponding to the current position of the deep-digging adjusting knob.

The advantages of this automatic grabbing are: in the operation process of the gantry crane, when the grab bucket falls to the material surface every time, the tightness states of the 4 steel wire ropes can be always kept the same as the tightness states of the 4 steel wire ropes before, namely, when the grab bucket grabs goods every time, the initial states are the same, the follow-up control modes are the same, the grabbing amount is the same, the error of the grabbing amount every time is reduced, and the stability of the optimal operation efficiency is ensured.

Based on the gantry crane grab bucket grabbing amount control system, the specific implementation steps of the control method for realizing quantitative and efficient grabbing operation on different materials are as follows:

determining the suitable opening angle of a grab bucket corresponding to a material to be grabbed by utilizing manual adjustment:

step 1: a driver of the portal crane rotates a material selection knob to a gear matched with the material according to the type of the material to be grabbed, and opens a deep digging start button; at the moment, a deep digging start button sends a grabbing signal to a PLC controller, and the PLC controller controls a winch motor driving shaft of a supporting mechanism to continuously and positively rotate to lower a supporting steel wire rope; when the PLC receives and collects that the weight value of the grab bucket transmitted by the overload system is 0, the grab bucket is lowered to the material level, and the PLC controls a driving shaft of a winch motor of the supporting mechanism to stop rotating; in the process, the material selection knob inputs an appointed signal to the PLC, the PLC controls a winch motor driving shaft of the opening and closing mechanism to rotate forwards for an appointed number of turns according to the appointed signal, and then the closed steel wire rope is released to an appointed length, so that the grab bucket is opened to an appointed opening angle corresponding to the current gear of the material selection knob;

step 2: a driver of the gantry crane manually controls a winch motor driving shaft of the opening and closing mechanism to rotate reversely, the opening and closing steel wire rope is tightened to a specified length, and the grab bucket returns to a closed state; then, a driver of the portal crane manually controls a winch motor driving shaft of the supporting mechanism to rotate reversely, and the two opening and closing steel wire ropes are lifted and tightened until the grab bucket leaves the material surface; at the moment, a driver of the gantry crane observes the weight value of the grab bucket displayed by the overload system in real time to judge whether the grabbing mode reaches the maximum operation capacity of the gantry crane or not;

and step 3: if the weight value of the grab bucket does not reach or exceed the maximum operation capacity of the gantry crane in the step 2, a gantry crane driver performs left-handed adjustment or right-handed adjustment on a deep digging adjustment knob based on a reference adjustment value displayed by a display screen so as to finely adjust the number of rotation turns of a driving shaft of a winch motor of the opening and closing mechanism, and further realize adjustment on the specified lowering length of the opening and closing steel wire rope; starting the deep digging start button again, sending a grabbing signal to the PLC by the deep digging start button, and controlling the winch motor driving shaft of the supporting mechanism to rotate continuously in the forward direction by the PLC until the weight value of the grab bucket transmitted by the overload system is collected by the PLC to be 0; meanwhile, a specified signal is input into the PLC by the deep-digging adjusting knob, the PLC controls a winch motor driving shaft of the opening and closing mechanism to rotate forward for a specified number of turns according to the specified signal, and then the closed steel wire rope is released to a specified length, so that the grab bucket is lowered to the material surface again and is opened to a specified opening angle according to the adjusting value of the deep-digging adjusting knob;

repeating the step 2 and the step 3 until the opening angle of the grab bucket correspondingly reaches a proper opening angle according to the adjusting value of the deep digging adjusting knob, namely the material grabbing amount of the grab bucket under the opening angle reaches the maximum operation capacity of the gantry crane; the adjusting value corresponding to the deep digging adjusting knob is the optimal adjusting value of the material grabbing operation at this time;

(II) keeping the grab bucket to be opened to a proper opening angle every time, and completing material grabbing by adopting an automatic grabbing mode:

keeping the deep digging adjusting knob at the optimal adjusting value, and pressing an automatic grabbing starting button; at the moment, the PLC controller automatically controls the grab bucket to complete four actions of descending, opening, closing and ascending; in particular, the amount of the solvent to be used,

the PLC controller controls a winch motor driving shaft of the supporting mechanism to continuously rotate in the forward direction, a supporting steel wire rope is released downwards, the grab bucket gradually descends to the surface of a material to be grabbed, meanwhile, the PLC controller controls the winch motor driving shaft of the opening and closing mechanism to rotate in the forward direction for a specified number of turns, and the steel wire rope is released downwards for a specified length, so that the grab bucket is opened to a proper opening angle in the descending process;

when the PLC acquires that the weight value of the grab bucket detected by the overload system is 0, the grab bucket is indicated to descend to the material level; at the moment, the PLC controls a motor driving shaft of a winch of the opening and closing mechanism to rotate reversely for a specified number of turns, the opening and closing steel wire rope is lifted and tightened to a specified length, the grab bucket is completely closed, and the material grabbing is finished;

the PLC controller controls a winding motor driving shaft of the supporting mechanism to rotate continuously in the reverse direction, the supporting steel wire ropes are tightened by lifting, when the numerical difference transmitted by the opening and closing mechanism displacement sensor and the supporting mechanism displacement sensor is 0, the rope difference between the two opening and closing steel wire ropes and the two supporting steel wire ropes is 0, and the grab bucket is lifted to a safe height at the moment, so that the grabbing action is finished;

and subsequently, a gantry crane driver manually operates the grab bucket to transport and grab the materials to the specified target position.

In the process of the step (I) and the step (II), the PLC calculates whether the rope difference between the support steel wire rope and the opening and closing steel wire rope exceeds a set threshold value according to position signals input by the support mechanism position sensor and the opening and closing mechanism position sensor so as to judge whether the steel wire rope is in a loose state; when the PLC calculates that the rope difference exceeds a set threshold value, the rotating speed of a motor driving shaft of the supporting mechanism winch or the rotating speed of a motor driving shaft of the opening and closing mechanism winch is controlled to be adjusted according to the current movement speeds of the supporting steel wire rope and the opening and closing steel wire rope collected by the speed encoder of the supporting mechanism and the speed encoder of the opening and closing mechanism.

The gantry crane grab bucket grabbing amount control system is firstly installed on a 15# gantry crane of an applicant operation goods yard and performs material grabbing operation trial operation. During the trial run, the operation efficiency of the 15# portal crane with the portal crane grab bucket grabbing amount control system and the average operation efficiency of the 12# to 16# portal crane without the portal crane grab bucket grabbing amount control system are compared and tested, and the specific test results are shown in the following table 2.

Table 2:

serial number

Name of ship

Goods and their use

Specific gravity of

15# gantry crane efficiency

Average efficiency of 12# -16# gantry crane

Rate of efficiency improvement

1

Linda (Chinese character of' Linda

Yangdi powder

1.9

552.6t/h

488.5t/h

13.12％

2

Blue moon

Mike powder

2.1

515.8t/h

488t/h

5.70％

3

Kristina

Brazil powder

2.3

550.6t/h

500t/h

10.12％

4

Tuantong (a Chinese character of 'Jitong')

FOR powder

2.27

539.7t/h

520.3t/h

3.73％

5

Illusion

Ukrainia powder

2.2

547.4t/h

493t/h

11.03％

6

Huahai sea

SP powder

2.2

567.6t/h

524.6t/h

8.20％

7

Dream of silver river

PB powder

2.1

531.6t/h

489.6t/h

8.58％

8

Starlight avenue

Yangdi powder

2

554.9t/h

475.5t/h

16.70％

9

Angel transport

Brazil powder

2.54

592.9t/h

516t/h

14.90％

From the comparison data results in table 2, it is seen that, in the operation process of six gantry cranes operating on the same cargo of the same ship, the operation efficiency of the 15# gantry crane is obviously improved compared with the average operation efficiency of the five other gantry cranes, and the efficiency improvement rate can reach 16.70% at most.

Meanwhile, in the trial operation process, the single-person operation efficiency of six drivers (drivers A-F for short) specialized in the 15# portal crane in the operation process after the portal crane grab bucket grabbing amount control system is installed and the average operation efficiency of all drivers of the goods yard 12# -16# portal crane are counted, and specific statistical results are shown in the following tables 3-8.

Table 3: driver A job efficiency statistics

Table 4: driver B job efficiency statistics

Table 5: driver C job efficiency statistics

Table 6: driver D job efficiency statistics

Table 7: driver E job efficiency statistics

Table 8: driver F job efficiency statistics

As can be seen from the statistics of the single-person operation efficiency data counted in the table 3-8, the single-person operation efficiency of the driver of the door machine is improved by comparing the average operation efficiency of six drivers of the 15# door machine with the average operation efficiency of all drivers driving the 12# to 16# door machine, and the maximum improvement range of the efficiency reaches 15.96 percent

In addition, the gantry crane grab bucket grabbing amount control system is analyzed from the economic perspective of the applicant enterprises. From the perspective of saving the grab bucket and realizing economic value, if the applicant carries out transformation of ten door machines frequently carrying out bulk cargo operation, the reserve of the grab bucket is reduced, and each grab bucket is 20 ten thousand yuan, and 10 door machines need about 12 grab buckets (10 normal machines and 2 standby machines) according to the calculation of reducing one grab bucket, so that the cost can be saved by 240 ten thousand yuan. From the viewpoint of improving the working efficiency and realizing the economic value, if the working amount is increased by 6%, the working amount can be increased by 30 ten thousand tons by 10 gantry cranes. The profit per ton is calculated by 8 yuan, and the economic benefit of 30X 8-240 ten thousand yuan can be created in one year.

Claims (4)

1. The utility model provides a quick-witted grab bucket grabbing amount control system which characterized in that includes:

a) a support mechanism position sensor installed on a rotation mechanism of a hoist of the support mechanism to collect a rotation position signal of a motor driving shaft of the hoist of the support mechanism;

b) an opening and closing mechanism position sensor which is arranged on a rotating mechanism of a winding engine of the opening and closing mechanism so as to collect a rotating position signal of a motor driving shaft of the winding engine of the opening and closing mechanism;

c) the support mechanism speed encoder is arranged on a motor driving shaft of a winch of the support mechanism so as to acquire a rotating speed signal of the motor driving shaft of the winch of the support mechanism;

d) the opening and closing mechanism speed encoder is arranged on a motor driving shaft of a winch of the opening and closing mechanism so as to detect a rotating speed signal of the motor driving shaft of the winch of the opening and closing mechanism;

e) a PLC controller arranged in a control box arranged on the side surface of the linkage table in the cab of the door machine; the PLC is respectively and electrically connected with a support mechanism position sensor and a switching mechanism displacement sensor, and the PLC is respectively and electrically connected with a support mechanism speed encoder and a switching mechanism speed encoder; the PLC controller is electrically connected with a winch of the supporting mechanism through a frequency converter A, the PLC controller is electrically connected with a winch of the opening and closing mechanism through a frequency converter B, and the PLC controller is electrically connected with an overload system which is arranged in a matched manner with the grab bucket per se; and

f) an operation panel provided on an upper surface of the control box; the operation panel is provided with a display screen electrically connected with the PLC, a material selection knob electrically connected with the PLC through a digital quantity input module, a deep digging adjustment knob connected with the PLC through an analog quantity input module, a deep digging start button electrically connected with the PLC, and an automatic grabbing start button electrically connected with the PLC; the deep digging adjusting knob adopts an electrodeless knob.

2. The door grapple grabbing amount control system according to claim 1, wherein the supporting mechanism position sensor and the opening and closing mechanism position sensor are hall sensors, which are mounted on the motor rotor assembly.

3. The gantry crane grab bucket grabbing amount control system according to claim 1, wherein an upper display frame and a lower display frame are arranged; the upper display frame is used for displaying the numerical value corresponding to the current gear of the material selection knob; and the lower display frame is used for displaying the numerical value corresponding to the current position of the deep-digging adjusting knob.

4. A gantry crane grab control method realized based on the gantry crane grab control system according to claim 1, characterized by comprising the following steps:

determining an appropriate opening angle of a grab bucket corresponding to a material to be grabbed:

step 1: rotating a material selection knob to a gear matched with the material, and starting a deep digging start button; a deep digging starting button sends a grabbing signal to a PLC controller, and the PLC controller controls a winch motor driving shaft of a supporting mechanism to continuously rotate in the forward direction until the PLC controller acquires that the weight value of the grab bucket transmitted by an overload system is 0; meanwhile, the material selection knob inputs an appointed signal to the PLC, the PLC controls a driving shaft of a winch motor of the opening and closing mechanism to rotate forwards for an appointed number of turns according to the appointed signal, and then the closed steel wire rope is released to an appointed length, so that the grab bucket is opened to an appointed opening angle;

step 2: the grab bucket grabs the material at a specified opening angle and lifts the material away from the material surface, and whether the grabbing reaches the maximum operation capacity of the gantry crane or not is judged according to the grab bucket weight value displayed by the overload system in real time;

and step 3: if the weight value of the grab bucket does not reach or exceed the maximum operation capacity of the gantry crane in the step 2, adjusting the number of rotation turns of a driving shaft of a winch motor of the opening and closing mechanism by adjusting a deep digging adjusting knob so as to finely adjust the specified opening angle of the grab bucket; starting the deep-digging starting button again, sending a grabbing signal to the PLC by the deep-digging starting button, and controlling the winch motor driving shaft of the supporting mechanism to continuously rotate in the forward direction by the PLC until the weight value of the grab bucket transmitted by the overload system is collected by the PLC to be 0; meanwhile, a specified signal is input into the PLC by the deep digging adjusting knob, the PLC controls a driving shaft of a winch motor of the opening and closing mechanism to rotate forward for a specified number of turns according to the specified signal, and then the closed steel wire rope is released to a specified length, so that the grab bucket is opened to a new specified opening angle;

repeating the step 2 to the step 3, wherein the specified opening angle of the grab bucket meets the requirement that the material grabbing amount reaches the maximum operation capacity of the gantry crane; the corresponding numerical value of the deep digging adjusting knob is the optimal adjusting value;

and (II) finishing all material grabbing in an automatic grabbing manner based on the opening angle determined in the step (I):

keeping the deep digging adjusting knob at the optimal adjusting value, and starting an automatic grabbing starting button; an automatic grabbing start button inputs an automatic grabbing operation signal to the PLC;

the PLC controller controls a winch motor driving shaft of the supporting mechanism to continuously rotate in the forward direction, meanwhile, a deep digging adjusting knob inputs a designated signal to the PLC controller, the PLC controller controls the winch motor driving shaft of the opening and closing mechanism to rotate in the forward direction for a designated number of turns, a closed steel wire rope is released for a designated length below the designated number of turns, and the grab bucket is opened to a designated opening angle in the descending process;

when the PLC acquires that the weight value of the grab bucket detected by the overload system is 0, the PLC controls a motor driving shaft of a winch of the opening and closing mechanism to rotate reversely for a specified number of turns, the opening and closing steel wire rope is pulled up and tightened to a specified length, the grab bucket is closed, and the grabbing of the material is completed;

when the PLC acquires that the rotating speed input by the speed encoder of the opening and closing mechanism is 0, the PLC controls a winding motor driving shaft of the supporting mechanism to continuously rotate in the reverse direction, the supporting steel wire ropes are lifted and tightened, when the numerical difference transmitted by the displacement sensor of the opening and closing mechanism and the displacement sensor of the supporting mechanism is 0, the rope difference between the two opening and closing steel wire ropes and the two supporting steel wire ropes is 0, the grab bucket leaves the material slowly at the moment, the grabbing action is finished, and the rotating bucket can be controlled to be transferred to a target position for unloading;

in the process of the step (I) and the step (II), the PLC calculates whether the rope difference between the support steel wire rope and the opening and closing steel wire rope exceeds a set threshold value according to position signals input by the support mechanism position sensor and the opening and closing mechanism position sensor so as to judge whether the steel wire rope is in a loose state; when the PLC calculates that the rope difference exceeds a set threshold value, the rotating speed of a motor driving shaft of the supporting mechanism winch or the rotating speed of a motor driving shaft of the opening and closing mechanism winch is controlled to be adjusted according to the current movement speeds of the supporting steel wire rope and the opening and closing steel wire rope collected by the speed encoder of the supporting mechanism and the speed encoder of the opening and closing mechanism.

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