CN114455472A - Control system for moment balance of crane grab bucket lifting motor - Google Patents
Control system for moment balance of crane grab bucket lifting motor Download PDFInfo
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- CN114455472A CN114455472A CN202210098136.5A CN202210098136A CN114455472A CN 114455472 A CN114455472 A CN 114455472A CN 202210098136 A CN202210098136 A CN 202210098136A CN 114455472 A CN114455472 A CN 114455472A
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- 229910000831 Steel Inorganic materials 0.000 claims description 7
- 239000010959 steel Substances 0.000 claims description 7
- 238000004804 winding Methods 0.000 claims description 7
- 239000003638 chemical reducing agent Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 description 7
- 230000007246 mechanism Effects 0.000 description 3
- 230000001174 ascending effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
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- 230000007547 defect Effects 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C13/00—Other constructional features or details
- B66C13/18—Control systems or devices
- B66C13/48—Automatic control of crane drives for producing a single or repeated working cycle; Programme control
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C13/00—Other constructional features or details
- B66C13/18—Control systems or devices
- B66C13/22—Control systems or devices for electric drives
- B66C13/32—Control systems or devices for electric drives for operating grab bucket hoists by means of one or more electric motors used both for hosting and lowering the loads and for opening and closing the bucket jaws
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- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Mechanical Engineering (AREA)
- Control And Safety Of Cranes (AREA)
Abstract
The invention relates to a control system for moment balance of a crane grab bucket lifting motor, which comprises a grab bucket consisting of two bucket-shaped jaws, a master controller, a PLC, a supporting motor and an opening and closing motor, wherein the supporting motor and the opening and closing motor have the same rated moment, the master controller is used for transmitting an operation command to the PLC, and the PLC outputs a corresponding control command to frequency converters of the supporting motor and the opening and closing motor according to the received operation command, the real-time output moments of the supporting motor and the opening and closing motor and the real-time rotation displacement of the supporting motor and the opening and closing motor, so that the motion control of the grab bucket is realized. The invention can greatly improve the control precision of two hoisting motors for realizing torque balance, shorten the time required by realizing double-machine balance, effectively avoid the phenomenon of long overload time of a single hoisting motor, and improve the stability and the safety of the crane grab bucket during operation.
Description
Technical Field
The invention belongs to the field of crane control, and particularly relates to a control system for moment balance of a crane grab bucket lifting motor.
Background
The operation of the grab bucket is used as a main operation working condition of the crane, and the loading and unloading efficiency and the safety of the grab bucket directly influence the operation efficiency of the bulk cargo wharf. The grab operation generally requires two lifting motors to hoist simultaneously, when the lifting motor No. 1 (supporting motor) and the lifting motor No. 2 (switching motor) run at the same speed, the grab ascends or descends, and when the lifting motor No. 1 (supporting motor) and the lifting motor No. 2 (switching motor) run at different speeds, the grab is opened or closed. During the closing and lifting process of the grab bucket, two motors are required to distribute equal loads, and therefore the two motors are required to balance the torque of the loads. However, after the grab bucket grabs the goods and is closed, the hoisting motor is in a state of unbalanced moment and loose hoisting steel wire rope in most cases. Therefore, the aim of double-motor torque balance is achieved by adjusting the speeds of the two motors.
The existing control method mainly comprises a frequency converter, a motor, an operation room controller and a PLC. The two hoisting motors are driven by a frequency converter respectively, the electrical control of the two hoisting motors is mutually matched, and the operation command of the system is given by a master controller of a control room through a PLC. In the process of closing and lifting the grab bucket, fixed speed deviation is given by judging the torque difference of the two lifting motors, so that the torque balance of the two lifting motors is realized. However, the control method for giving the fixed speed deviation by only judging the torque difference of the two lifting motors has low control precision, easily causes that a single lifting motor is in an overload state for a long time, greatly damages lifting mechanisms (including steel wire ropes, motors, speed reducers, frequency converters and the like) corresponding to the motor during operation in the overload state for a long time, and has great potential safety hazards.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a control system for moment balance of a crane grab bucket lifting motor, which adopts the following technical scheme:
a control system for torque balance of a crane grab bucket lifting motor comprises a grab bucket consisting of two bucket-shaped jaw plates, a master controller, a PLC, a supporting motor and an opening and closing motor, wherein the supporting motor and the opening and closing motor have the same rated torque;
the bucket-shaped jaw plates are respectively controlled by steel wire ropes wound on two independent winding drums;
the supporting motor and the opening and closing motor are respectively and correspondingly connected with the two winding drums through speed reducers and are used for driving the winding drums to rotate to wind and unwind the steel wire rope so as to control the movement of the grab bucket; when the supporting motor and the opening and closing motor operate at the same speed, the grab bucket rises or falls, and when the supporting motor and the opening and closing motor operate at different speeds, the grab bucket is opened or closed;
the pulse encoders are arranged on the rotating shafts of the supporting motor and the opening and closing motor, and are connected with the PLC through a high-speed counter and used for acquiring the rotating speed and the rotating displacement of the supporting motor and the opening and closing motor;
the support motor and the opening and closing motor are respectively connected with the PLC through a frequency converter, and the frequency converter adjusts the power supply frequency of the support motor and the opening and closing motor according to the control instruction of the PLC so as to control the rotating speed of the support motor and the rotating speed of the opening and closing motor;
the master controller is used for transmitting an operation command to the PLC, and the PLC outputs a corresponding control command to the frequency converters of the supporting motor and the opening and closing motor according to the received operation command, the real-time output torque of the supporting motor and the opening and closing motor and the real-time rotation displacement of the supporting motor and the opening and closing motor, so that the motion control of the grab bucket is performed.
Further, after the grab bucket is closed, the PLC acquires real-time output torque of the support motor and the opening and closing motor, whether the motor load is unbalanced or not is determined by comparing the output torque, if the motor load is unbalanced, the PLC generates compensation speed according to the dynamic rope difference of the support motor and the opening and closing motor and outputs the compensation speed to a frequency converter of the support motor or the opening and closing motor so as to adjust the rotating speed of the corresponding motor and further realize the motor load balance.
Further, the current values of the support motor and the opening and closing motor are used as respective output torques, if the current difference value between the opening and closing motor and the support motor is larger than a set torque adjusting point, the load of the support motor is overlarge, and the generated compensation speed needs to be output to the support motor until the load of the motor is restored to balance; if the current difference value between the switching motor and the supporting motor is smaller than the set moment balance point, the motor load is in a balanced state.
Further, the calculation formula of the dynamic rope difference is as follows:
Pos_sub＝(N1/4+D)-(N2/4+D)，
wherein Pos _ sub represents dynamic rope difference, N1、N2The pulse numbers of the encoders obtained by the high-speed counters corresponding to the support motor and the opening and closing motor are respectively shown, and D is set automatic opening and closing bucket data.
Further, the calculation formula of the compensation speed is as follows:
wherein Speed _ corr represents the compensation Speed, K is the adjustment coefficient,
indicating rounding.
Furthermore, the value range of the torque adjusting point is 10% -15% of the rated torque of the supporting motor and the opening and closing motor, and the value range of the torque balancing point is 5% -10% of the rated torque of the supporting motor and the opening and closing motor.
The invention has the beneficial effects that:
the invention solves the problems of low precision, poor torque balance effect, slow reaction speed and long overload time of a single motor of the method for realizing torque balance control by two lifting motors in the existing grab bucket operation. The original control method does not acquire the position signals of the two motors in real time through sensors such as an encoder, and the control method is too simple in calculation and too extensive in control. The invention can greatly improve the control precision of two hoisting motors for realizing torque balance, shorten the time required by realizing double-machine balance, effectively avoid the phenomenon of long overload time of a single hoisting motor, and improve the stability and the safety of the crane grab bucket during operation.
Drawings
FIG. 1 is a block diagram of a control system according to the present invention;
fig. 2 is a schematic diagram of the motor torque balance principle of the present invention.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings.
As shown in fig. 1, the invention mainly comprises a PLC system, a frequency converter, a pulse encoder, a master controller, a high-speed counting module, a torque balance control program of a hoisting motor, and the like. The specific functions are as follows:
1. the master controller: the position and the posture of the grab bucket are controlled, and the actions of ascending, descending, opening and closing the grab bucket are realized.
2. A frequency converter: and driving the motor to further drive the lifting mechanism executing mechanism to complete the operation task.
3. A pulse encoder: is arranged on a high-speed shaft of the motor and forms closed-loop control together with the frequency converter to play a role in speed feedback
And the effect of position measurement.
4. Hoisting a motor: the grab bucket lifting, descending, bucket opening, bucket closing and other actions are completed by driving the winding drum and the steel wire rope, and the grab bucket lifting, descending, bucket opening, bucket closing and other actions comprise a supporting motor and an opening and closing motor which are respectively used for controlling two bucket-shaped jaw plates of the grab bucket.
5. PLC: and receiving sensor signals from an operation table, an encoder for field detection and the like, and controlling the operation of the frequency converter according to preset logic.
6. A high-speed counter: and reading the encoder data to complete position measurement.
7. A torque balance control program of a hoisting motor: and the PLC control logic program is loaded in the PLC and is used for realizing rapid and accurate motor torque balance.
The operation platform main command gives an operation command, the PLC outputs an operation command and a speed command under the condition of meeting a certain external condition, the frequency converter is enabled to operate and output the speed through Profibus-DP bus communication, a lifting motor is driven to hoist, and the functions of ascending, descending, opening and closing of the grab bucket are realized.
After the grab bucket closing operation is finished, the PLC reads the real-time output torque of the motors, and compares the torque of the two lifting motors in a torque balance control program. When the torque difference value of the two motors exceeds a certain range, the conclusion that the load of one motor is larger is obtained through calculation. Meanwhile, the real-time position deviations of the two hoisting motors are compared, the compensation speed is calculated according to the difference, then the speed of the motor with larger load is adjusted, and the moment balance of the two motors is rapidly and accurately realized, as shown in fig. 2.
In this embodiment, the current values of the support motor and the switching motor are used as respective output torques, and if the current difference between the switching motor and the support motor is greater than a set torque adjustment point (45A, which is generally 10% to 15% of the rated torque of the motor), it indicates that the load of the support motor is too large, and the generated compensation speed needs to be output to the support motor until the load of the motor is restored to balance; if the current difference between the switching motor and the supporting motor is less than the set torque balance point (25A, generally 5% -10% of the rated torque of the motor), it means that the motor load is in a balanced state.
The calculation formula of the dynamic rope difference is as follows:
Pos_sub＝(N1/4+D)-(N2/4+D)，
wherein Pos _ sub represents dynamic rope difference, N1、N2The pulse numbers of the encoders obtained by the high-speed counters corresponding to the support motor and the opening and closing motor are respectively shown, and D is set automatic opening and closing bucket data.
The calculation formula of the compensation speed is as follows:
wherein Speed _ corr represents the compensation Speed, K is the adjustment coefficient, which can be set according to the actual situation on site, in this embodiment, K takes the value of 5,
indicating rounding.
The above are only preferred embodiments of the present invention, and the scope of the present invention is not limited to the above examples, and all technical solutions that fall under the spirit of the present invention belong to the scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.
Claims (6)
1. A control system for moment balance of a crane grab bucket lifting motor is characterized by comprising a grab bucket consisting of two bucket-shaped jaw plates, a master controller, a PLC, a supporting motor and an opening and closing motor, wherein the supporting motor and the opening and closing motor have the same rated moment;
the bucket-shaped jaw plates are respectively controlled by steel wire ropes wound on two independent winding drums;
the supporting motor and the opening and closing motor are respectively and correspondingly connected with the two winding drums through speed reducers and are used for driving the winding drums to rotate to wind and unwind the steel wire rope so as to control the movement of the grab bucket; when the supporting motor and the opening and closing motor operate at the same speed, the grab bucket rises or falls, and when the supporting motor and the opening and closing motor operate at different speeds, the grab bucket is opened or closed;
the pulse encoders are arranged on the rotating shafts of the supporting motor and the opening and closing motor, and are connected with the PLC through a high-speed counter and used for acquiring the rotating speed and the rotating displacement of the supporting motor and the opening and closing motor;
the support motor and the opening and closing motor are respectively connected with the PLC through a frequency converter, and the frequency converter adjusts the power supply frequency of the support motor and the opening and closing motor according to the control instruction of the PLC so as to control the rotating speed of the support motor and the rotating speed of the opening and closing motor;
the master controller is used for transmitting an operation command to the PLC, and the PLC outputs a corresponding control command to the frequency converters of the supporting motor and the opening and closing motor according to the received operation command, the real-time output torque of the supporting motor and the opening and closing motor and the real-time rotation displacement of the supporting motor and the opening and closing motor, so that the motion control of the grab bucket is performed.
2. The torque balance control system of the crane grab bucket lifting motor according to claim 1, wherein after the grab bucket is closed, the PLC obtains real-time output torque of the support motor and the opening and closing motor, determines whether the motor load is unbalanced or not by comparing the output torque, and if the motor load is unbalanced, the PLC generates compensation speed according to the dynamic rope difference of the support motor and the opening and closing motor and outputs the compensation speed to a frequency converter of the support motor or the opening and closing motor so as to adjust the rotating speed of the corresponding motor and further realize the motor load balance.
3. The torque balance control system of the crane grab bucket lifting motor according to claim 2, wherein the current values of the supporting motor and the opening and closing motor are used as respective output torques, if the current difference value between the opening and closing motor and the supporting motor is greater than a set torque adjusting point, the load of the supporting motor is over-large, and the generated compensation speed needs to be output to the supporting motor until the load of the motor is restored to balance; if the current difference value between the switching motor and the supporting motor is smaller than the set moment balance point, the motor load is in a balanced state.
4. The control system for moment balance of the crane grab bucket hoisting motor according to claim 2, wherein the calculation formula of the dynamic rope difference is as follows:
Pos_sub＝(N1/4+D)-(N2/4+D)，
wherein Pos _ sub represents dynamic rope difference, N1、N2The pulse numbers of the encoders obtained by the high-speed counters corresponding to the support motor and the opening and closing motor are respectively shown, and D is set automatic opening and closing bucket data.
5. The control system for moment balance of the crane grab bucket lifting motor according to claim 4, wherein the calculation formula of the compensation speed is as follows:
wherein Speed _ corr represents the compensation Speed, K is the adjustment coefficient,
indicating rounding.
6. The control system for the moment balance of the crane grab bucket lifting motor according to claim 3, wherein the value range of the moment adjusting point is 10% -15% of the rated moment of the supporting motor and the opening and closing motor, and the value range of the moment balancing point is 5% -10% of the rated moment of the supporting motor and the opening and closing motor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210098136.5A CN114455472A (en) | 2022-01-27 | 2022-01-27 | Control system for moment balance of crane grab bucket lifting motor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210098136.5A CN114455472A (en) | 2022-01-27 | 2022-01-27 | Control system for moment balance of crane grab bucket lifting motor |
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| CN114455472A true CN114455472A (en) | 2022-05-10 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202210098136.5A Pending CN114455472A (en) | 2022-01-27 | 2022-01-27 | Control system for moment balance of crane grab bucket lifting motor |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01203194A (en) * | 1988-02-09 | 1989-08-15 | Hitachi Kiden Kogyo Ltd | Hoist control method for crane provided with rope type bucket |
| JP2002128465A (en) * | 2000-10-23 | 2002-05-09 | Kojimagumi:Kk | Horizontal excavation controller for grab-type dredge |
| CN103771270A (en) * | 2014-01-09 | 2014-05-07 | 苏州汇川技术有限公司 | Bucket closing lifting control system and method of four-rope grab bucket crane |
| CN104627838A (en) * | 2014-12-30 | 2015-05-20 | 武汉港迪电气有限公司 | Synchronous control method for non-rigidity connection of working condition of gantry crane hook |
| CN108675141A (en) * | 2018-06-08 | 2018-10-19 | 江苏金恒信息科技股份有限公司 | A kind of system and method for four rope grab crawl slag charge |
-
2022
- 2022-01-27 CN CN202210098136.5A patent/CN114455472A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01203194A (en) * | 1988-02-09 | 1989-08-15 | Hitachi Kiden Kogyo Ltd | Hoist control method for crane provided with rope type bucket |
| JP2002128465A (en) * | 2000-10-23 | 2002-05-09 | Kojimagumi:Kk | Horizontal excavation controller for grab-type dredge |
| CN103771270A (en) * | 2014-01-09 | 2014-05-07 | 苏州汇川技术有限公司 | Bucket closing lifting control system and method of four-rope grab bucket crane |
| CN104627838A (en) * | 2014-12-30 | 2015-05-20 | 武汉港迪电气有限公司 | Synchronous control method for non-rigidity connection of working condition of gantry crane hook |
| CN108675141A (en) * | 2018-06-08 | 2018-10-19 | 江苏金恒信息科技股份有限公司 | A kind of system and method for four rope grab crawl slag charge |
Non-Patent Citations (2)
| Title |
|---|
| 张建文: "基于PLC变频调速控制的智能抓斗在门式起重机中的应用研究", 《物流工程与管理》 * |
| 李晓明等: "基于PLC和ACS800变频器桥式抓斗电气控制***的设计", 《重工与起重技术》 * |
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Application publication date: 20220510 |