Steel wire rope steady-state control system for discharging, taking and lifting of grab bucket of grab bucket ship unloader

Abstract

The invention discloses a steady-state control system for a steel wire rope for blanking, taking and lifting a grab bucket of a grab bucket ship unloader. The steady-state control system comprises a steel wire rope state monitoring unit, a control unit and a control unit, wherein the steel wire rope state monitoring unit is used for detecting the stress state change when the steel wire rope is lifted and opened and closed; the PLC control unit is used for judging the tensioning and loosening states of the steel wire rope during lifting and opening and closing based on the stress state variation, transmitted by the steel wire rope state monitoring unit, of the steel wire rope during lifting and opening and closing, and sending out a control instruction; the mechanism driving unit is used for receiving the control instruction transmitted by the PLC control unit, steel wire rope steady-state control under the working process of discharging, taking or lifting of the grab ship unloader is achieved, the system reduces steel wire rope impact in the discharging, taking and lifting process of the grab, and the service life of a steel wire rope is prolonged; and structural impact in the ship unloading operation process of equipment is reduced, and the overall service life of the equipment is prolonged.

Description

Technical Field

[0001] The invention belongs to the field of grab ship unloaders and relates to a steel wire rope steady-state control system for material dropping, material taking and lifting of a grab ship unloader. Background Art

[0002] As an important ship unloading equipment at bulk material terminals, grab ship unloaders suspend and drive grabs through wire ropes to complete ship unloading operations such as opening the bucket to drop materials, closing the bucket to pick up materials, lifting, translation, and opening the bucket to unload materials. During the ship unloading operation, errors in manual control operations often cause wire rope slack and wire rope impact, which greatly affects the life of the wire rope and increases the operating cost of replacing wire ropes at bulk material terminals. For this reason, it is urgently necessary to develop a steady-state control system for wire ropes for grab bucket drop, pick up, and lifting of grab ship unloaders, so that the control of wire ropes in the operation processes of grab bucket drop, pick up, and lifting, which are easy to damage wire ropes, is more stable, the occurrence of loose ropes and impact phenomena is reduced, and the loss of wire ropes is reduced, saving operating costs for bulk material terminals. Summary of the invention

[0003] In order to solve the above problems, the technical solution adopted by the present invention is: a steel wire rope steady-state control system for grab bucket unloader to drop, take and lift materials, comprising:

[0004] Wire rope status monitoring unit: used to detect changes in the stress state of the wire rope when it is hoisted and opened and closed;

[0005] PLC control unit: used to judge the tension and relaxation state of the wire rope during lifting and opening and closing based on the change in the force state of the wire rope transmitted by the wire rope state monitoring unit, and issue control instructions;

[0006] Mechanism driving unit: used to receive the control instructions transmitted by the PLC control unit to realize the steady-state control of the wire rope in the process of dropping, picking up or lifting the grab ship unloader.

[0007] Further: the wire rope status monitoring unit includes:

[0008] Lifting wire rope load sensor: used to detect the change of the force state of the lifting wire rope; installed on the lifting wire rope pulley device at the end of the boom;

[0009] Opening and closing wire rope load sensor: used to detect the change in the stress state of the opening and closing wire rope, and is installed on the opening and closing wire rope pulley device at the end of the boom.

[0010] Further: the mechanism driving unit comprises:

[0011] Lifting motor: used to drive the grab bucket mechanism to perform corresponding rising and falling actions;

[0012] Opening and closing motor: used to drive the grab mechanism to perform corresponding opening, closing, rising, and falling actions; trolley motor: used to drive the grab mechanism to perform corresponding translational movements in the sea side direction and the land side direction; hoisting frequency converter: used to control the speed change of the hoisting motor;

[0013] Opening and closing frequency converter: used to control the speed change of the opening and closing motor;

[0014] Trolley frequency converter: used to control the speed change of the trolley motor.

[0015] Furthermore, the PLC control unit includes:

[0016] Analog input module: used to receive the load change data of the hoisting wire rope and the opening and closing wire rope in the wire rope state monitoring unit;

[0017] PLC module: used to receive the load change data of the hoisting wire rope and the opening and closing wire rope transmitted by the analog input module, judge the tension and slack states of the hoisting and opening and closing wire ropes, and respectively send control commands to the hoisting frequency converter, the opening and closing frequency converter, and the trolley frequency converter to drive the hoisting motor, the opening and closing motor, and the trolley motor to operate, so as to achieve the steady-state control of the wire rope in the hopper unloading, material taking, and lifting operation processes of the grab ship unloader;

[0018] Switch: used to transmit the control commands of the PLC module to the hoisting frequency converter, the opening and closing frequency converter, and the trolley frequency converter.

[0019] According to any one of the control methods of the wire rope steady-state control system for the grab hopper unloading, material taking, and lifting of the grab ship unloader, it includes the following steps:

[0020] Step 1: The grab ship unloader starts to operate, and the wire rope steady-state control system for the grab hopper unloading, material taking, and lifting is activated;

[0021] Step 2: The grab of the grab mechanism opens and moves to a position above the target material grabbing position. The PLC module controls the hoisting wire rope and the opening and closing wire rope to descend, and the grab descends to prepare for hopper unloading;

[0022] Step 3: When the PLC module judges through the real-time data transmitted by the hoisting wire rope load sensor and the opening and closing wire rope load sensor that the grab has fallen onto the target material grabbing position, the grab stops descending, the hopper unloading process of the grab is completed, and the steady-state control judgment of the hopper unloading wire rope is carried out;

[0023] Step 4: The PLC module performs the steady-state control of the wire rope for the grab to close and take materials based on the real-time data of the hoisting wire rope load sensor and the opening and closing wire rope load sensor until the process of the grab closing and taking materials is completed;

[0024] Step Five: Based on the real-time data from the hoisting wire rope load sensor and the opening / closing wire rope load sensor of the grab, the PLC module conducts the steady-state control of the wire rope for grab hoisting until the grab reaches the height required to leave the ship's hold, and then proceeds with the process of the grab returning to the hopper for discharging to perform the ship unloading operation;

[0025] Step Six: Repeat the above steps during the operation of the grab ship unloader until the ship unloading operation is completed, and the functions of the steady-state control system for the wire ropes of grab dropping, material taking, and hoisting are turned off.

[0026] Furthermore, the process of judging the steady-state control of the grab dropping wire rope is as follows:

[0027] During the grab descending process, when W 起升 ≥ -0.5 * W 额定 * K a and W 开闭 ≥ -0.5 * W 额定 * K a it is judged that the grab has not come into contact with the material and has not started to drop;

[0028] During the grab descending process, when W 起升 < -0.5 * W 额定 * K a or W 开闭 < -0.5 * W 额定 * K a it is judged that the grab is starting to drop;

[0029] During the grab descending process, when W 起升 < -0.5 * W 额定 * K a and W 开闭 < -0.5 * W 额定 * K a it is judged that the grab has completed dropping;

[0030] Where: W 起升 is the detection data of the hoisting wire rope load sensor; W 开闭 is the detection data of the opening / closing wire rope load sensor; W 额定 is the sum of the detection data of the hoisting wire rope load sensor and the opening / closing wire rope load sensor when the grab is at the rated load; K a is the detection coefficient for judging dropping.

[0031] Furthermore: The process of the steady-state control of the grab closing for material taking of the wire rope is as follows:

[0032] The torque control command T of the hoisting frequency converter 起升 = (100% - i * 10%) * T 抓斗 ;

[0033] When W开闭 <0.5*W 额定 *K b When, the speed control command V of the open-close frequency converter 开闭 = 0.2*V max ;

[0034] When W 开闭 ≥ 0.5*W 额定 *K b When, the speed control command V of the open-close frequency converter 开闭 = V max ;

[0035] Wherein: i is the sinking degree of the grab bucket; T 抓斗 is the output torque required for the hoisting wire rope to support the empty grab bucket and hover in the air; W 开闭 is the detection data of the open-close wire rope load sensor; W 额定 is the sum of the detection data of the hoisting wire rope load sensor and the open-close wire rope load sensor when the grab bucket is at the rated load; K b is the steady-state control coefficient of the grab bucket closing and material-taking wire rope; V max is the maximum operating speed of hoisting and open-close.

[0036] Furthermore: The steady-state control process of the wire rope for lifting the grab bucket is as follows:

[0037] When W 起升 <0.5*W 额定 *K c Or W 开闭 <0.5*W 额定 *K c When, the speed control commands V of the hoisting frequency converter and the open-close frequency converter 提升 = 0.2*V 提升max ;

[0038] When W 起升 ≥ 0.5*W 额定 *K c And W 开闭 ≥ 0.5*W 额定 *K c When, the speed control commands V of the hoisting frequency converter and the open-close frequency converter 提升 = V 提升max ;

[0039] Where W 起升 is the detection data of the hoisting wire rope load sensor; W 开闭 is the detection data of the open-close wire rope load sensor; W 额定 is the sum of the detection data of the hoisting wire rope load sensor and the open-close wire rope load sensor when the grab bucket is at the rated load; K c is the steady-state control coefficient of the grab bucket lifting wire rope; Vmax is the maximum operating speed for hoisting and opening / closing.

[0040] A steel wire rope steady-state control system for the grab unloader's grab dropping, material taking, and lifting provided by the present invention makes the steel wire rope operation in the processes of grab dropping, material taking, and lifting in the ship unloading operation process more stable, avoids the occurrence of loose rope and impact phenomena, and improves the service life of the steel wire rope. The steel wire rope steady-state control system for the grab unloader's grab dropping, material taking, and lifting of this application has the following advantages:

[0041] Simple structure, low cost, and strong practicability;

[0042] Reduce the impact of the steel wire rope during the grab dropping, material taking, and lifting processes, and increase the service life of the steel wire rope;

[0043] Reduce the structural impact during the equipment's ship unloading operation, and improve the overall working life of the equipment. Brief Description of the Drawings

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0045] Figure 1 Layout diagram of the steel wire rope steady-state control system for the grab unloader's grab dropping, material taking, and lifting;

[0046] Figure 2 Architecture diagram of the steel wire rope steady-state control system for the grab unloader's grab dropping, material taking, and lifting;

[0047] Figure 3 Wiring diagram of the PLC control unit U1;

[0048] Figure 4 Wiring diagram of the mechanism drive unit U2;

[0049] Figure 5 Wiring diagram of the steel wire rope state monitoring unit U3;

[0050] Figure 6 Control flow chart of the steel wire rope steady-state control system for the grab unloader's grab dropping, material taking, and lifting.

[0051] Reference numerals: 100, wire rope status monitoring unit; 200, mechanism drive unit; 300, PLC control unit; 1, hoisting wire rope load sensor; 2, opening and closing wire rope load sensor; 3, grab; 4, analog input module; 5, switch; 6, PLC module; 7, trolley frequency converter; 8, trolley motor; 9, hoisting frequency converter; 10, opening and closing frequency converter; 11, hoisting motor; 12, opening and closing motor. Detailed implementation manners

[0052] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0053] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way serves as a limitation to the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0054] Figure 1 Layout diagram of the wire rope steady-state control system for the grab unloading and loading and lifting of the grab unloader

[0055] Figure 2 Architecture diagram of the wire rope steady-state control system for the grab unloading and loading and lifting of the grab unloader

[0056] A wire rope steady-state control system for the grab unloading, loading and lifting of a grab unloader, comprising:

[0057] The wire rope status monitoring unit 100: used to detect the change in the stress state of the wire rope during hoisting and opening and closing.

[0058] The PLC control unit 300: used to judge the tension and slack states of the hoisting and opening and closing wire ropes based on the change in the stress state of the wire rope during hoisting and opening and closing transmitted by the wire rope status monitoring unit 100, and issue a control instruction.

[0059] The mechanism drive unit 200: used to receive the control instruction transmitted by the PLC control unit 300 and realize the wire rope steady-state control during the grab unloading or loading or lifting operation process of the grab unloader 3.

[0060] The wire rope status monitoring unit 100 consists of a hoisting wire rope load sensor 1 and an opening / closing wire rope load sensor 2 installed at the end of the boom.

[0061] Hoisting wire rope load sensor 1: Used to detect the change in the stress state of the hoisting wire rope; installed on the hoisting wire rope pulley device at the end of the boom.

[0062] Opening / closing wire rope load sensor 2: Used to detect the change in the stress state of the opening / closing wire rope, installed on the opening / closing wire rope pulley device at the end of the boom.

[0063] The mechanism drive unit 200 consists of a hoisting frequency converter 9, an opening / closing frequency converter 10, a trolley frequency converter 7 installed in the electrical room, and a hoisting motor 11, an opening / closing motor 12, a trolley motor 8 installed in the machine room. Hoisting motor 11: Used to drive the grab mechanism to perform corresponding ascending and descending actions.

[0064] Opening / closing motor 12: Used to drive the grab mechanism to perform corresponding opening, closing, ascending, and descending actions; trolley motor 8: Used to drive the grab mechanism to perform corresponding translation in the sea side direction and the land side direction.

[0065] Hoisting frequency converter 9: Used to control the speed change of the hoisting motor 11.

[0066] Opening / closing frequency converter 10: Used to control the speed change of the opening / closing motor 12.

[0067] Trolley frequency converter 7: Used to control the speed change of the trolley motor 8.

[0068] Hoisting frequency converter 9, opening / closing frequency converter 10, trolley frequency converter 7: Used to control the speed change of the trolley motor 8.

[0069] Among them, the hoisting frequency converter 9, the opening / closing frequency converter 10, and the trolley frequency converter 7 receive control instructions from the PLC control unit 300 to control the operation of the hoisting motor 11, the opening / closing motor 12, and the trolley motor 8; the hoisting motor 11 and the opening / closing motor 12 drive the grab 3 mechanism to perform corresponding ascending and descending actions; the trolley motor 8 drives the grab 3 mechanism to perform corresponding translation actions.

[0070] The said PLC control unit 300 includes:

[0071] Analog input module 4: Used to receive the hoisting wire rope load change data and the opening / closing wire rope load change data in the wire rope status monitoring unit 100.

[0072] The PLC module 6: It is used to receive the data of the change in the load of the hoisting wire rope and the change in the load of the opening and closing wire rope transmitted by the analog input module 4, judge the tension and relaxation states of the hoisting wire rope and the opening and closing wire rope, and send control instructions to the trolley frequency converter 7 to drive the hoisting motor, the opening and closing motor, and the trolley motor 8 to operate, so as to achieve the steady-state control of the wire rope in the processes of the grab 3 ship unloader discharging, taking materials, and lifting operations;

[0073] Among them, the hoisting wire rope load sensor 1 is located on the hoisting wire rope pulley device at the end of the boom and is used to detect the stress state of the hoisting wire rope;

[0074] The opening and closing wire rope load sensor 2 is located on the opening and closing wire rope pulley device at the end of the boom and is used to detect the stress state of the opening and closing wire rope.

[0075] Embodiment 1:

[0076] The steady-state control system of the wire rope for the grab 3 ship unloader to discharge, take materials, and lift consists of three parts: the PLC control unit 300, the mechanism control unit 200, and the wire rope state monitoring unit 100. The system architecture diagram is as Figure 2 shown.

[0077] As Figure 3 shown, the PLC control unit 300 consists of the PLC module 6, the switch 5, and the AI module 4.

[0078] The PLC module 6 transmits the control instructions to the hoisting frequency converter 9, the opening and closing frequency converter 10, and the trolley frequency converter 7 in the mechanism drive unit 200 through the Profinet protocol via the switch 5.

[0079] The switch 5 supports the Profinet protocol and is used for data transmission between the PLC module 6 and the hoisting frequency converter 9, the opening and closing frequency converter 10, and the trolley frequency converter 7 in the mechanism drive unit 200. The AI module 4 collects the data of the hoisting wire rope load sensor 1 and the opening and closing wire rope load sensor 2 in the wire rope state monitoring unit 100 in a hard-wired form and transmits it to the PLC module 6.

[0080] As Figure 4 shown, the mechanism drive unit 200 consists of the hoisting frequency converter 9, the opening and closing frequency converter 10, the trolley frequency converter 7, and the hoisting, opening and closing trolley motors 8. After the hoisting frequency converter 9, the opening and closing frequency converter 10, and the trolley frequency converter 7 obtain the hoisting, opening and closing, and trolley control instructions of the PLC module 6 in the PLC control unit 300, they drive the hoisting motor 11, the opening and closing motor 12, and the trolley motor 8 to perform corresponding operating actions in a hard-wired form, so as to achieve the steady-state control of the wire rope in the processes of the grab 3 ship unloader discharging, taking materials, and lifting operations.

[0081] AsFigure 5 As shown, the wire rope status monitoring unit 100 consists of the hoisting and opening / closing wire rope load sensors 2. The hoisting wire rope load sensor 1 and the opening / closing wire rope load sensor 2 transmit the force conditions of the hoisting wire rope and the opening / closing wire rope to the analog input module 4 in the PLC control unit 300 in the form of 4 - 20mA analog data through a hardware line.

[0082] The layout diagram of the wire rope steady-state control system for the grab bucket unloading ship unloader during grab bucket discharging, material fetching, and lifting is as Figure 1 shown.

[0083] The specific control method of the wire rope steady-state control system for the grab bucket unloading ship unloader during grab bucket discharging, material fetching, and lifting is as follows:

[0084] Step 1: The grab bucket unloading ship unloader starts operation, and the functions of the wire rope steady-state control system for the grab bucket 3 during discharging, material fetching, and lifting are activated;

[0085] Step 2: The grab bucket opens and moves to a position above the target material grabbing position. The PLC module 6 controls the hoisting and opening / closing wire ropes to descend, and the grab bucket 3 descends in preparation for discharging;

[0086] Step 3: When the PLC module 6 determines, based on the real-time data from the hoisting wire rope load sensor 1 and the opening / closing wire rope load sensor 2, that the grab bucket 3 has reached the target material grabbing position, the grab bucket 3 stops descending, and the discharging process of the grab bucket 3 is completed. The method for judging the wire rope steady-state control during the discharging of the grab bucket 3 is as follows:

[0087] During the descent of the grab bucket 3, when W 起升 ≥ -0.5 * W 额定 * K a and W 开闭 ≥ -0.5 * W 额定 * K a it is judged that the grab bucket 3 has not come into contact with the material and has not started discharging;

[0088] During the descent of the grab bucket 3, when W 起升 < -0.5 * W 额定 * K a or W 开闭 < -0.5 * W 额定 * K a it is judged that the grab bucket 3 is starting to discharge;

[0089] During the descent of the grab bucket 3, when W 起升 < -0.5 * W 额定 * K a and W 开闭 < -0.5 * W 额定 * K a it is judged that the grab bucket 3 has completed discharging.

[0090] Wherein: W 起升 is the detection data of the hoisting wire rope load sensor 1; W 开闭 is the detection data of the opening and closing wire rope load sensor 2; W 额定 is the sum of the detection data of the hoisting and opening and closing wire rope load sensors 2 when the grab 3 is at the rated load; K a is the detection coefficient for judging material dropping, with a value of 0.1.

[0091] Step Four: The PLC module 6 performs the steady-state control of the wire ropes for the grab 3 to close the bucket and take materials until the process of the grab 3 closing the bucket and taking materials is completed. The steady-state control method of the wire ropes for the grab 3 to close the bucket and take materials is as follows:

[0092] The torque control instruction T of the hoisting frequency converter 7 起升 =(100%-i*10%)*T 抓斗3 ;

[0093] When W 开闭 <0.5*W 额定 *K b , the speed control instruction V of the opening and closing frequency converter 7 开闭 =0.2*V max ;

[0094] When W 开闭 ≥0.5*W 额定 *K b , the speed control instruction V of the opening and closing frequency converter 7 开闭 =V max ;

[0095] Wherein: i is the sinking degree of the grab 3, divided into 1-10 gears, corresponding to the values 1-10; T 抓斗3 is the output torque required for the hoisting wire rope to support the empty grab 3 and hover in the air; W 开闭 is the detection data of the opening and closing wire rope load sensor 2; W 额定 is the sum of the detection data of the hoisting wire rope load sensor and the opening and closing wire rope load sensor when the grab 3 is at the rated load; K b is the steady-state control coefficient of the wire ropes for the grab 3 to close the bucket and take materials, with a value of 0.3; V max is the maximum operating speed of hoisting and opening and closing.

[0096] Step Five: The PLC module 6 performs the steady-state control of the wire ropes for the grab 3 to lift until the grab 3 reaches the height required to leave the cabin, and then performs the process of the grab 3 returning to the hopper to unload materials for ship unloading operation. The steady-state control method of the wire ropes for the grab 3 to lift is as follows:

[0097] When W起升 <0.5*W 额定 *K c or W 开闭 <0.5*W 额定 *K c When <0.5*W 提升 *K 提升max ;

[0098] When W 起升 ≥0.5*W 额定 *K c and W 开闭 ≥0.5*W 额定 *K c When, the speed control commands V of the hoisting frequency converter 9 and the opening and closing frequency converter 7 提升 =V 提升max .

[0099] Where W 起升 is the detection data of the hoisting wire rope load sensor 1; W 开闭 is the detection data of the opening and closing wire rope load sensor 2; W 额定 is the sum of the detection data of the hoisting and opening and closing wire rope load sensors 2 when the grab 3 is at the rated load; K c is the steady-state control coefficient of the hoisting wire rope of the grab 3, with a value of 0.6; V max is the maximum operating speed of hoisting and opening and closing.

[0100] Step 6: Repeat the above steps during the operation of the grab 3 ship unloader until the ship unloading operation is completed, and the functions of the steady-state control system for the wire ropes of the grab 3 during falling, loading, and hoisting are turned off.

[0101] Taking the 1800t / h grab 3 ship unloader and a 50,000-ton bulk carrier as an example, the control process of the steady-state control system for the wire ropes of the grab 3 during falling, loading, and hoisting of the grab 3 ship unloader is described. As Figure 6 shown: The grab 3 ship unloader starts operating, and the functions of the steady-state control system for the wire ropes of the grab 3 during falling, loading, and hoisting are activated; the grab 3 opens and moves to a position above the target material-grabbing level, and the grab 3 descends for material falling. When it is judged that the grab 3 has reached the target material-grabbing level, the grab 3 stops descending, and the material-falling process of the grab 3 is completed. The steady-state control of the wire rope for the grab 3 to close and grab materials is carried out until the grab 3 closes. The steady-state control of the wire rope for the grab 3 to hoist is carried out until the grab 3 reaches the height required to leave the cabin, and then the process of the grab 3 returning to the hopper for unloading is carried out for the ship unloading operation. Repeat the above steps until the ship unloading operation is completed, and the functions of the steady-state control system for the wire ropes of the grab 3 during falling, loading, and hoisting are turned off.

[0102] The present technology provides a wire rope steady-state control system for the grab bucket of a grab ship unloader during the processes of grab bucket discharging, material fetching, and lifting, making the wire rope operation in the processes of grab bucket discharging, material fetching, and lifting in the ship unloading operation process more stable, avoiding the occurrence of loose rope and impact phenomena, prolonging the service life of the wire rope, reducing the operation cost of the bulk cargo terminal, and enhancing the safety and reliability of the operation of the bulk cargo terminal. The research and development of the wire rope steady-state control system for the grab bucket of a grab ship unloader greatly increases the market core competitiveness of the grab ship unloader product.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A steady-state control system for the steel wire ropes of a grab ship unloader during grab discharging, material taking, and lifting, characterized in that: Including: Steel wire rope status monitoring unit: used to detect the change in the force state of the steel wire rope during hoisting and opening / closing; PLC control unit: used to judge the tension and slack states of the steel wire rope during hoisting and opening / closing based on the change amount of the force state of the steel wire rope transmitted by the steel wire rope status monitoring unit, and issue control instructions; Mechanism drive unit: used to receive the control instructions transmitted by the PLC control unit and realize the steady-state control of the steel wire rope in the material discharging, material taking or lifting operation process of the grab ship unloader.

2. The steady-state control system for the steel wire ropes of the grab unloader's grab for material dropping, material taking, and lifting according to claim 1, wherein: The steel wire rope status monitoring unit includes: Hoisting wire rope load sensor: used to detect the change in the force state of the hoisting wire rope; arranged on the hoisting wire rope pulley device at the end of the boom; Opening / closing wire rope load sensor: used to detect the change in the force state of the opening / closing wire rope, arranged on the opening / closing wire rope pulley device at the end of the boom.

3. The steady-state control system of the steel wire rope for the grab bucket's blanking, material taking, and lifting of a grab ship unloader according to claim 1, characterized in that: The mechanism drive unit includes: Hoisting motor: used to drive the grab mechanism to perform corresponding rising and falling actions; Opening / closing motor: used to drive the grab mechanism to perform corresponding opening, closing, rising and falling actions; Trolley motor: used to drive the grab mechanism to perform corresponding translational movements in the sea side direction and the land side direction; Hoisting frequency converter: used to control the speed change of the hoisting motor; Opening / closing frequency converter: used to control the speed change of the opening / closing motor; Trolley frequency converter: used to control the speed change of the trolley motor.

4. The steady-state control system for the steel wire ropes of the grab bucket's material dropping, material picking, and lifting of a grab unloader according to claim 1, characterized in that: The PLC control unit includes: Analog input module: used to receive the load change data of the hoisting wire rope and the opening / closing wire rope in the steel wire rope status monitoring unit; PLC module: used to receive the load change data of the hoisting wire rope and the opening / closing wire rope transmitted by the analog input module, judge the tension and slack states of the hoisting wire rope and the opening / closing wire rope, and respectively issue control instructions to the hoisting frequency converter, the opening / closing frequency converter and the trolley frequency converter to drive the hoisting motor, the opening / closing motor and the trolley motor to run, so as to realize the steady-state control of the steel wire rope in the material discharging, material taking and lifting operation processes of the grab ship unloader; Switch: used to transmit the control instructions of the PLC module to the hoisting frequency converter, the opening / closing frequency converter and the trolley frequency converter.

5. The control method of the wire rope steady state control system for the grab discharging, material taking and lifting of a grab ship unloader according to any one of claims 1-4, characterized in that: Including the following steps: Step 1: The grab ship unloader starts to operate, and the steady-state control system of the steel wire rope for grab material discharging, material taking and lifting is activated; Step 2: The grab of the grab mechanism opens and moves to a position above the target material grabbing position. The PLC module controls the hoisting wire rope and the opening / closing wire rope to descend, and the grab descends to prepare for material discharging; Step 3: When the PLC module judges through the real-time data transmitted by the hoisting wire rope load sensor and the opening / closing wire rope load sensor that the grab has fallen onto the target material grabbing position, the grab stops descending, the grab material discharging process is completed, and the steady-state control of the steel wire rope for grab material discharging is judged; Step 4: The PLC module performs the steady-state control of the steel wire rope for grab material taking with the grab closed based on the real-time data of the hoisting wire rope load sensor and the opening / closing wire rope load sensor until the grab material taking process with the grab closed is completed; Step 5: The PLC module performs the steady-state control of the hoisting wire rope of the grab according to the real-time data of the hoisting wire rope load sensor and the opening and closing wire rope load sensor until the grab reaches the height required to leave the cabin, and then proceeds with the process of the grab returning to the hopper for discharging to perform the ship unloading operation; Step 6: Repeat the above steps during the operation of the grab ship unloader until the ship unloading operation is completed, and the function of the steady-state control system of the wire ropes for grab dropping, material taking, and hoisting is turned off.

6. The control method of the wire rope steady state control system for the grab discharging, material taking and lifting of a grab unloader according to claim 5, characterized in that: The process of the steady-state control judgment of the grab dropping wire rope is as follows: During the process of the grab bucket descending, when W 起升 ≥ -0.5 * W 额定 * K a and W 开闭 ≥ -0.5 * W 额定 * K a it is determined that the grab bucket has not come into contact with the material and the material discharge has not started; During the process of the grab bucket descending, when W 起升 <-0.5*W 额定 *K a or W 开闭 <-0.5*W 额定 *K a it is determined that the grab bucket is starting to discharge materials; During the process of the grab bucket descending, when W 起升 <-0.5*W 额定 *K a and W 开闭 <-0.5*W 额定 *K a it is determined that the grab bucket has completed discharging materials; Among them: W 起升 is the detection data of the hoisting wire rope load sensor; W 开闭 is the detection data of the opening and closing wire rope load sensor; W 额定 is the sum of the detection data of the hoisting wire rope load sensor and the opening and closing wire rope load sensor when the grab is at the rated load; K a is the detection coefficient for judging material discharge.

7. The control method of the steel wire rope steady-state control system for the grab bucket discharging, material taking and lifting of a grab unloader according to claim 5, characterized in that: The process of the steady-state control of the grab closing and material taking wire rope is as follows: Hoisting frequency converter torque control command T 起升 =(100% - i * 10%) * T 抓斗 ; When W 开闭 <0.5 * W 额定 * K b , the on - off inverter speed control command V 开闭 = 0.2 * V max ; When W 开闭 ≥ 0.5 * W 额定 * K b the on - off frequency converter speed control command V 开闭 = V max ; Where: i is the sinking degree of the grab; T 抓斗 is the output torque required for the hoisting wire rope to support the empty grab and hover in the air; W 开闭 is the detection data of the opening and closing wire rope load sensor; W 额定 is the sum of the detection data of the hoisting wire rope load sensor and the opening and closing wire rope load sensor when the grab is at the rated load; K b is the steady-state control coefficient of the grab closing and material-taking wire rope; V max is the maximum operating speed of hoisting and opening and closing.

8. The control method of the wire rope steady state control system for the grab unloading, material taking and lifting of a grab ship unloader according to claim 5, characterized in that: The process of the steady-state control of the hoisting wire rope of the grab is as follows: When W 起升 <0.5*W 额定 *K c or W 开闭 <0.5*W 额定 *K c the speed control commands V of the hoisting frequency converter and the opening / closing frequency converter 提升 = 0.2*V 提升max ; When W 起升 ≥0.5*W 额定 *K c and W 开闭 ≥0.5*W 额定 *K c at this time, the speed control commands V of the hoisting frequency converter and the opening and closing frequency converter 提升 =V 提升max ; Among which W 起升 is the detection data of the hoisting wire rope load sensor; W 开闭 is the detection data of the opening and closing wire rope load sensor; W 额定 is the sum of the detection data of the hoisting wire rope load sensor and the opening and closing wire rope load sensor when the grab is at the rated load; K c is the steady-state control coefficient of the grab hoisting wire rope; V max is the maximum operating speed of hoisting and opening / closing.

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