Grab control system, method, crane and computer-readable storage medium

Abstract

The present invention discloses a grab control system, method, crane and computer-readable storage medium, belonging to the technical field of crane control. The grab control system proposed by the present invention realizes the control of the grab through the opening and closing frequency converters capable of master-slave communication and the supporting frequency converter, reducing the electrical transformation cost of old lifting equipment. The supporting frequency converter can dynamically obtain the state information of the supporting motor and receive the state information of the opening and closing motor obtained by the supporting frequency converter, and generate a supporting motor operating frequency command and an opening and closing motor operating frequency command based on the supporting motor state information and the opening and closing motor state information to drive the supporting motor and the opening and closing motor to operate. During the operation of the motor, the supporting frequency converter can realize the closed-loop control of the grab and the automatic deceleration of the grab according to the dynamically obtained feedback information, improving the working efficiency of the crane grab, reducing the operation complexity of the crane grab control and the labor intensity of the operator.

Description

Technical Field

[0001] The present invention relates to the technical field of crane control, and particularly to a grab control system, method, crane, and computer-readable storage medium. Background Art

[0002] Grab cranes are often used for loading and unloading heavy objects such as slag, bulk materials, and coal, and are important engineering machinery and equipment in the production processes of steel mills, ports, coal mining enterprises, etc. The grab of a crane is an important part that determines the working ability and working efficiency of the crane. The coordination of the traditional crane grab opening and closing machine and the supporting machine completely depends on the proficiency and operation level of the operator. Since manual operation cannot achieve precise control, problems such as wire rope breakage and wire rope jamming often occur during operation.

[0003] Therefore, the prior art uses a PLC (Programmable Logic Controller) as a control unit to implement all grab logic calculations and control functions. However, this technology has the problem of high electrical transformation cost for old lifting equipment, and in the opening and closing bucket control, it is necessary to preset the reference values for opening and closing the bucket. The parameter setting is complex and the reference values need to be manually changed for different working conditions. It cannot automatically obtain the pulse / rope length conversion coefficient and cannot achieve automatic deceleration of opening and closing the bucket without relying on the preset reference values, which greatly reduces the usability and increases the operation complexity. Summary of the Invention

[0004] The main object of the present invention is to provide a grab control system, method, crane, and computer-readable storage medium, aiming to solve the technical problem of how to reduce the electrical transformation cost of old lifting equipment.

[0005] To achieve the above object, the present invention provides a grab control system, and the grab control system includes:

[0006] A support mechanism, the support mechanism including a support frequency converter and a support motor;

[0007] An opening and closing mechanism, the opening and closing mechanism including an opening and closing frequency converter and an opening and closing motor;

[0008] The support frequency converter is communicatively connected to the opening and closing frequency converter;

[0009] The opening and closing frequency converter is used to dynamically obtain the state information of the opening and closing motor and send the state information of the opening and closing motor to the support frequency converter;

[0010] The support frequency converter is used to dynamically obtain the support motor status information and receive the opening and closing motor status information, generate a support motor operating frequency command and an opening and closing motor operating frequency command based on the support motor status information and the opening and closing motor status information, and execute the support motor operating frequency command to drive the support motor to operate;

[0011] The support frequency converter is also used to send the opening and closing motor operating frequency command to the opening and closing frequency converter so that the opening and closing frequency converter receives and executes the opening and closing motor operating frequency command to drive the opening and closing motor to operate.

[0012] Optionally, the grab control system further includes:

[0013] A support encoder, which is arranged on the motor shaft of the support motor and is communicatively connected with the support frequency converter, and is used to obtain the support motor pulses in the support motor status information;

[0014] An opening and closing encoder, which is arranged on the motor shaft of the opening and closing motor and is communicatively connected with the opening and closing frequency converter, and is used to obtain the opening and closing motor pulses in the opening and closing motor status information.

[0015] Optionally, the support frequency converter includes:

[0016] An automatic unit conversion module, which is used to obtain a support motor pulse conversion coefficient according to the support motor pulses and obtain an opening and closing motor pulse conversion coefficient according to the opening and closing motor pulses.

[0017] Optionally, the support frequency converter further includes:

[0018] A grab calibration module, which is used to perform calibration according to the support motor pulses, the support motor pulse conversion coefficient, the opening and closing motor pulses, the opening and closing motor pulse conversion coefficient and preset calibration parameters to generate grab position parameters.

[0019] Optionally, the support frequency converter further includes:

[0020] A speed deviation calculation module, which is used to determine an opening bucket reference value and a closing bucket reference value according to the grab position parameters, and generate an opening bucket automatic deceleration scheme and a closing bucket automatic deceleration scheme based on the opening bucket reference value and the closing bucket reference value.

[0021] Optionally, the support frequency converter further includes:

[0022] A speed limiting module, which is used to limit the preset support motor speed and the preset opening and closing motor speed so that there is a speed difference between the opening and closing motor and the support motor.

[0023] Optionally, the support frequency converter further includes:

[0024] A load balancing module, which is used to obtain the output torque of the support motor and the output torque of the opening and closing motor, and adjust the speed output of the opening and closing motor according to the output torque of the support motor and the output torque of the opening and closing motor.

[0025] In addition, to achieve the above object, the present invention also provides a grab control method, which is applied to the grab control system as described above. The grab control method includes the following steps:

[0026] When a start command is received, based on the support frequency converter, an operation frequency command for the support motor and an operation frequency command for the opening and closing motor are output;

[0027] Based on the support frequency converter, execute the operation frequency command of the support motor to drive the support motor to operate;

[0028] Based on the support frequency converter, send the operation frequency command of the opening and closing motor to the opening and closing frequency converter so that the opening and closing frequency converter receives and executes the operation frequency command of the opening and closing motor to drive the opening and closing motor to operate.

[0029] In addition, to achieve the above object, the present invention also provides a grab control method, which is applied to the support frequency converter. The grab control method includes the following steps:

[0030] When a start command is received, generate and output an operation frequency command for the support motor and an operation frequency command for the opening and closing motor according to the start command;

[0031] Execute the operation frequency command of the support motor to drive the support motor connected to the support frequency converter to operate;

[0032] Send the operation frequency command of the opening and closing motor to the opening and closing frequency converter to drive the opening and closing motor connected to the opening and closing frequency converter to operate.

[0033] In addition, to achieve the above object, the present invention also provides a grab control method, which is applied to the opening and closing frequency converter. The grab control method includes the following steps:

[0034] Receive the operation frequency command of the opening and closing motor generated and output by the support frequency converter according to the start command;

[0035] Execute the operation frequency command of the opening and closing motor to drive the opening and closing motor connected to the opening and closing frequency converter to operate.

[0036] In addition, to achieve the above object, the present invention further provides a crane, which includes: a memory, a processor, and a grab control program stored on the memory and operable on the processor. When the grab control program is executed by the processor, the steps of the grab control method described above are implemented.

[0037] In addition, to achieve the above object, the present invention further provides a computer-readable storage medium, on which a grab control program is stored. When the grab control program is executed by a processor, the steps of the grab control method described above are implemented.

[0038] The present invention provides a grab control system, method, crane, and computer-readable storage medium, which overcome the problem in the prior art that the high electrical transformation cost of old lifting equipment is caused by using a PLC as a control unit to implement all grab logic calculations and control functions. In the grab control system of the present invention, the support frequency converter and the opening and closing frequency converter can perform master-slave communication. Based on the support frequency converter and the opening and closing frequency converter, all grab logic calculations and control functions are realized, reducing the electrical transformation cost of old lifting equipment. The support frequency converter can dynamically obtain the support motor status information and receive the opening and closing motor status information obtained by the support frequency converter, and generate a support motor operating frequency command and an opening and closing motor operating frequency command based on the support motor status information and the opening and closing motor status information to drive the support motor and the opening and closing motor to operate. During the operation of the motor, the support frequency converter can implement grab closed-loop control and grab automatic deceleration according to the dynamically obtained feedback information, improving the working efficiency of the crane grab, reducing the operation complexity of the crane grab control, and the labor intensity of the operator. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic structural diagram of an embodiment of the grab control system of the present invention;

[0040] Figure 2 It is a schematic refined structural diagram of an embodiment of the grab control system of the present invention;

[0041] Figure 3 It is a schematic diagram of the functional modules of the support frequency converter in an embodiment of the grab control system of the present invention;

[0042] Figure 4 It is a schematic principle diagram of the automatic deceleration scheme of the opening and closing bucket in an embodiment of the grab control system of the present invention;

[0043] Figure 5 It is a schematic structural diagram of the crane of the hardware operating environment involved in the embodiment scheme of the present invention;

[0044] Figure 6 It is a schematic flow diagram of an embodiment of the grab control method of the present invention.

[0045] The implementation, functional features and advantages of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0046] It should be understood that the specific embodiments described herein are merely used to explain the present invention and are not used to limit the present invention.

[0047] An embodiment of the present invention provides a grab control system. Refer to Figure 1 , Figure 1 which is a schematic structural diagram of an embodiment of the grab control system of the present invention.

[0048] In this embodiment, the grab control system includes:

[0049] A support mechanism 10, and the support mechanism 10 includes a support frequency converter 100 and a support motor 101;

[0050] An opening and closing mechanism 20, and the opening and closing mechanism 20 includes an opening and closing frequency converter 200 and an opening and closing motor 201;

[0051] The support frequency converter 100 is communicatively connected to the opening and closing frequency converter 200;

[0052] The opening and closing frequency converter 200 is configured to dynamically obtain the state information of the opening and closing motor and send the state information of the opening and closing motor to the support frequency converter 100;

[0053] The support frequency converter 100 is configured to dynamically obtain the state information of the support motor and receive the state information of the opening and closing motor, generate a support motor operation frequency command and an opening and closing motor operation frequency command based on the state information of the support motor and the state information of the opening and closing motor, and execute the support motor operation frequency command to drive the support motor 101 to operate;

[0054] The support frequency converter 100 is further configured to send the opening and closing motor operation frequency command to the opening and closing frequency converter 200 so that the opening and closing frequency converter 200 receives and executes the opening and closing motor operation frequency command to drive the opening and closing motor 201 to operate.

[0055] It should be noted that, in this embodiment, the support mechanism 10 is the host, and the support frequency converter 100 is used to drive the support motor 101 to operate, so as to realize the lifting of the grab bucket; the opening and closing mechanism 20 is the slave, and the opening and closing frequency converter 200 is used to drive the opening and closing motor 201 to operate, so as to realize the opening and closing of the grab bucket; the support frequency converter 100 has a built-in logic calculation unit and a control unit, which are used to provide control logic for the opening and closing operations of the grab bucket; the grab bucket control system in this embodiment realizes data interaction based on the master-slave communication between the support frequency converter 100 and the opening and closing frequency converter 200, and the master-slave communication is realized based on the communication protocol provided by the support frequency converter 100 and the opening and closing frequency converter 200. The support frequency converter 100 is electrically connected to the support motor 101, and the opening and closing frequency converter 200 is electrically connected to the opening and closing motor 201.

[0056] As an example, the grab bucket control system further includes:

[0057] A supporting encoder, the supporting encoder is arranged on the motor shaft of the supporting motor 101 and is in communication connection with the supporting frequency converter 100, the supporting encoder is used to obtain the supporting motor pulse in the supporting motor state information;

[0058] An opening and closing encoder is arranged on the motor shaft of the opening and closing motor 201 and is in communication connection with the opening and closing frequency converter 200 . The opening and closing encoder is used to obtain the opening and closing motor pulse in the opening and closing motor status information.

[0059] It should be understood that neither the supporting inverter 100 nor the opening and closing inverter 200 can directly obtain the supporting motor status information and the opening and closing motor status information. The supporting motor status information and the opening and closing motor status information are fed back to the supporting inverter 100 by the supporting motor pulses and the opening and closing motor pulses read by the supporting encoder and the opening and closing encoder. The supporting motor pulses are read by the supporting encoder and sent to the supporting inverter 100. The opening and closing motor pulses are read by the opening and closing encoder and sent to the opening and closing inverter 200, and then sent to the supporting inverter 100 by the opening and closing inverter 200 based on the master-slave communication. At this point, the supporting inverter 100 can obtain the supporting motor position and the opening and closing motor position based on the received supporting motor pulses and the opening and closing motor pulses, and then calculate the current switch state of the grab according to the encoder pulse signal, and further judge whether it is necessary to adjust the speed and torque of the supporting motor 101 and the opening and closing motor 201 based on the current switch state of the grab.

[0060] Furthermore, for ease of understanding, this embodiment also provides a detailed structural diagram of the grab bucket control system, such as Figure 2 As shown, from Figure 2It can be known from this that the encoder 102 is the above-mentioned support encoder. The support motor 101 is connected to the transmission device 103, the transmission device 103 is connected to the winding drum 104, and the winding drum 104 is connected to the grab 30 through the support rope 105; the encoder 202 is the above-mentioned opening and closing encoder, the opening and closing motor 201 is connected to the transmission device 203, the transmission device 203 is connected to the winding drum 204, and the winding drum 204 is connected to the grab 30 through the opening and closing rope 205.

[0061] It can be understood that when the support motor 101 starts to operate, it can drive the winding drum 104 to rotate through the transmission device 103, and then drive the support rope 105 to realize the lifting operation of the grab 30; when the opening and closing motor 201 starts to operate, it can drive the winding drum 204 to rotate through the transmission device 203, and then drive the opening and closing rope 205 to realize the opening and closing operation of the grab 30.

[0062] This embodiment proposes a grab control system, which overcomes the problem of high electrical transformation cost of old lifting equipment caused by the need to use a PLC as a control unit to implement all grab logic calculations and control functions in the prior art. In this embodiment, the support frequency converter and the opening and closing frequency converter in the grab control system can perform master-slave communication. This embodiment realizes all grab logic calculations and control functions based on the support frequency converter and the opening and closing frequency converter, reducing the electrical transformation cost of old lifting equipment. The support frequency converter can dynamically obtain the support motor status information and receive the opening and closing motor status information obtained by the support frequency converter, and generate a support motor operation frequency command and an opening and closing motor operation frequency command based on the support motor status information and the opening and closing motor status information to drive the support motor and the opening and closing motor to operate. In this embodiment, without using a host computer PLC or a third controller, only by the encoders installed in the opening and closing and support motors to feedback the position, the grab closed-loop control can be realized. Compared with the traditional open-loop control, the opening and closing degree of the grab can be dynamically adjusted in real time according to the feedback opening value, ensuring that the grab opening and closing actions can be in place at one time, avoiding the operator needs to jog multiple times to make the grab reach the required opening and closing positions, improving the working efficiency of the crane grab, and reducing the operation complexity of the crane grab control and the labor intensity of the operator.

[0063] Furthermore, in this embodiment, the function modules included in the support frequency converter 100 are supplemented. Refer to Figure 3 , Figure 3 which is a schematic diagram of the function modules of the support frequency converter in an embodiment of the grab control system of the present invention.

[0064] As an example, in this embodiment, the support frequency converter 100 includes:

[0065] An automatic unit conversion module 110, which is used to obtain a support motor pulse conversion coefficient according to the support motor pulse and obtain an opening and closing motor pulse conversion coefficient according to the opening and closing motor pulse.

[0066] It should be noted that in the calibration of the opening and closing bucket, the encoder resolutions, transmission ratios of the opening and closing mechanism and the support mechanism, and the radius of the drum may be inconsistent, and the calculation of the rope difference completely depends on the pulses of the encoder. Therefore, it is necessary to convert the pulses of the two encoders into the same reference system, that is, convert the encoder pulses into the rope length. In the prior art, generally, it is necessary to manually calculate the conversion coefficient between the pulses and the rope length. This method is complex and prone to calculation errors. Therefore, in this embodiment, the above automatic unit conversion module 110 is added to the support frequency converter 100. Based on this module, the operator only needs to enable the automatic unit conversion module 110 before calibrating the opening and closing bucket and input the rope length to be measured, so that the opening and closing motor or the support motor runs a certain distance according to the input rope length and then stops. The pulses corresponding to this distance are obtained through the encoder. After the opening and closing motor or the support motor is enabled, the corresponding proportional relationship between the pulses and the rope length, that is, the support motor pulse conversion coefficient and the opening and closing motor pulse conversion coefficient, can be obtained.

[0067] As an example, in this embodiment, the support frequency converter 100 further includes:

[0068] A grab calibration module 120, which is used to perform calibration according to the support motor pulse, the support motor pulse conversion coefficient, the opening and closing motor pulse, the opening and closing motor pulse conversion coefficient, and a preset calibration parameter to generate grab position parameters.

[0069] It should be noted that the control scheme used in the grab control system provided in this embodiment is a closed-loop control scheme. The premise of the closed-loop control scheme is to obtain the absolute position difference of the grab, and judge the opening degree of the grab according to the real-time position difference and the absolute position difference, so as to realize the automatic opening and closing bucket action. Therefore, in this embodiment, the above grab calibration module 120 is added to the support frequency converter 100 to perform opening and closing bucket calibration. The grab calibration module 120 includes an opening degree calculation module. When performing opening and closing bucket calibration, the input values of the opening degree calculation module include the parameters set by the operator (that is, the preset calibration parameters): closing bucket calibration selection, closing bucket calibration delay time, opening bucket calibration selection, opening bucket calibration delay time, and the support motor position calculated based on the support motor encoder pulse (that is, the opening and closing motor pulse) and the support motor pulse conversion coefficient, and the opening and closing motor position calculated based on the opening and closing motor encoder pulse (that is, the support motor pulse) and the opening and closing motor pulse conversion coefficient; the output values (that is, the grab position parameters) include the opening bucket position difference, the closing bucket position difference, the absolute position difference, the real-time position difference, and the real-time opening degree value. Among them, the following relationships exist between the input and output values:

[0070] Absolute position difference = open bucket position difference - closed bucket position difference;

[0071] Real-time position difference = (support motor position - opening and closing motor position) - closed bucket position difference;

[0072] Real-time opening value = real-time position difference / absolute position difference.

[0073] In this embodiment, when the real-time opening value is close to 0, the grab bucket is determined to be in the open bucket state, and when the real-time opening value is close to 1, the grab bucket is determined to be in the closed bucket state.

[0074] It can be understood that based on the above automatic conversion module 110 and the grab bucket calibration module 120, the support frequency converter 100 in this embodiment already has the function of converting encoder pulses into rope lengths, that is, the support frequency converter 100 can obtain the real-time opening value according to the dynamic feedback information of the encoder, and dynamically adjust the opening and closing degree of the grab bucket according to the real-time opening value, ensuring that the opening and closing actions of the grab bucket can be in place at one time, avoiding the problem that the traditional open-loop control requires the operator to issue operation instructions multiple times.

[0075] As an example, in this embodiment, the support frequency converter 100 further includes:

[0076] A speed deviation calculation module 130, which is used to determine the open bucket reference value and the closed bucket reference value according to the grab bucket position parameter, and generate an open bucket automatic deceleration scheme and a closed bucket automatic deceleration scheme based on the open bucket reference value and the closed bucket reference value.

[0077] It should be noted that during the opening and closing process of the grab bucket, due to the inertia of the object, the grab bucket first accelerates until the speed reaches a certain reference value, and then adjusts the acceleration to decelerate until it stops opening and closing. In the prior art, the setting of the pre-opening and pre-closing reference values is also preset through manual calculation, and it is impossible to achieve automatic deceleration of the opening and closing without a reference value. For different application scenarios, the reference value needs to be adjusted and modified, which requires a high debugging level for the operator, and because the debugging takes a long time, the work efficiency is low. Therefore, in this embodiment, the above speed deviation calculation module 130 is added to the support frequency converter 100, and the opening change amount is calculated in combination with the grab bucket position parameter obtained by the grab bucket calibration module 120, and the absolute value of the difference between the opening set value (set by the operator) and the real-time opening value is compared with the opening change amount to obtain the node for entering the automatic deceleration stage.

[0078] For easy understanding, this embodiment provides a Figure 4 schematic diagram of the opening and closing bucket automatic deceleration scheme as shown in Figure 4It can be seen that the horizontal axis represents the operating time of the grab during the opening or closing process, and the vertical axis represents the operating speed of the grab. When setting the closing or opening speed of the grab, it is required to decelerate from v2 to v1 with an acceleration of a within time t. Then, the change in the opening required for the speed to decrease from v2 to v1 is S. ABCD ;

[0079] The difference between the set value of the opening and the real-time value of the opening is ΔS = |set value of the opening - real-time value of the opening|.

[0080] Therefore, when ΔS ≤ S ABCD is satisfied, that is when, the grab enters the automatic deceleration stage of opening or closing.

[0081] As an example, in this embodiment, the support frequency converter 100 further includes:

[0082] A speed limiting module 140, which is used to limit the preset support motor speed and the preset opening and closing motor speed, so that there is a speed difference between the opening and closing motor and the support motor.

[0083] It should be noted that since the opening and closing of the grab is essentially achieved by controlling the speed difference between the support motor and the opening and closing motor, therefore, to ensure that the expected grab action can be realized, the above speed limiting module 140 is added to the support frequency converter 100 in this embodiment. Based on the speed limiting module 140, it is possible to limit according to the speed setting of the support motor and the opening and closing motor and the output torque of the support motor and the opening and closing motor, ensuring that there is a speed difference between the speed output of the support motor and the speed output of the opening and closing motor under any given speed of the support motor (i.e., the preset support motor speed) and the opening and closing motor speed (i.e., the preset opening and closing motor speed), so that the grab can meet the expected action.

[0084] As an example, in this embodiment, the support frequency converter 100 further includes:

[0085] A load balancing module 150, which is used to obtain the output torque of the support motor and the output torque of the opening and closing motor, and adjust the speed output of the opening and closing motor according to the output torque of the support motor and the output torque of the opening and closing motor.

[0086] It should be noted that the outputs of the support motor and the opening / closing motor include the output speed and torque output. During the operation of the grab bucket, due to the existence of the speed difference between the two motors, the load of the support mechanism and the opening / closing mechanism is often uneven, which will increase the burden on the corresponding motors. Therefore, in this embodiment, the above-mentioned load balancing module 150 is added to the support frequency converter 100 to add a load balancing control scheme for auxiliary in the grab bucket closed-loop control scheme. Specifically, the load balancing module 150 includes a filtering module and a load balancing controller. The output torques of the support motor and the opening / closing motor are filtered and then input into the load balancing controller, and then superimposed on the opening / closing motor speed output through the output of the above-mentioned speed limiting module 140. When the output torque of the opening / closing motor is greater than the output torque of the support motor, the output speed of the opening / closing motor is reduced through the adjustment of the load balancing controller; otherwise, the output speed of the opening / closing motor is increased, and finally dynamic load balancing is achieved, avoiding the situation that the grab bucket is opened and the materials are scattered during the lifting process.

[0087] In this embodiment, a support frequency converter in a grab bucket control system is provided, which overcomes the problems of the existing grab bucket control technology that it needs to rely on a host computer or a third controller, the control scheme is complex and costly, it cannot automatically obtain the pulse / rope length conversion coefficient, and it cannot achieve automatic deceleration of the opening / closing bucket without relying on a preset reference value. This embodiment realizes logical operation and control functions based on a support frequency converter integrated with multiple functional modules, without relying on a host computer PLC or a third controller. Only by the encoder feedback positions installed in the opening / closing motor and the support motor can the grab bucket closed-loop control be realized. Compared with the open-loop control, the opening degree of the grab bucket can be dynamically adjusted in real time according to the real-time opening value converted from the feedback information, ensuring that the opening / closing action of the grab bucket can be in place at one time, avoiding the operator needing to reach the position required for the grab bucket opening / closing through multiple jogging operations; at the same time, in this embodiment, a load balancing controller is adopted in the grab bucket closed-loop control to achieve dynamic balance during the lifting of the closed bucket, realizing an accurate control effect, improving the efficiency of the crane grab bucket, and effectively reducing the labor intensity of the operator.

[0088] The embodiment of the present invention also provides a crane, and the crane includes the above-mentioned grab bucket control system and can be applied to each embodiment of the above-mentioned grab bucket control system. Refer to Figure 5 , Figure 5 is a schematic diagram of the crane structure of the hardware operating environment involved in the embodiment of the present invention.

[0089] As Figure 5As shown in the figure, the crane may include: a processor 1001, such as a CPU, a network interface 1004, a user interface 1003, a memory 1005, and a communication bus 1002. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The user interface 1003 may include a display screen (Display) and an input unit such as a keyboard (Keyboard). Optionally, the user interface 1003 may further include a standard wired interface and a wireless interface. The network interface 1004 may optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The memory 1005 may be a high-speed RAM memory or a stable memory (non-volatile memory), such as a disk memory. Optionally, the memory 1005 may also be a storage device independent of the aforementioned processor 1001.

[0090] Those skilled in the art can understand that Figure 5 the crane structure shown in does not constitute a limitation on the crane, and may include more or fewer components than shown in the figure, or combine some components, or have different component arrangements.

[0091] As Figure 5 shown, the memory 1005, as a computer storage medium, may include an operating system, a network communication module, a user interface module, and a grab control program.

[0092] In Figure 5 the crane shown, the network interface 1004 is mainly used for data communication with other devices; the user interface 1003 is mainly used for data interaction with users; the processor 1001 and the memory 1005 in the crane of the present invention may be arranged in the crane. The crane calls the grab control program stored in the memory 1005 through the processor 1001 and executes the grab control method provided by the embodiments of the present invention.

[0093] The embodiments of the present invention further provide a grab control method, which is applied to the above grab control system. Referring to Figure 6 , Figure 6 is a schematic flow chart of an embodiment of the grab control method of the present invention.

[0094] In this embodiment, the grab control method includes:

[0095] Step S10, when a start instruction is received, output a support motor operating frequency instruction and an opening and closing motor operating frequency instruction based on the support frequency converter;

[0096] Step S20, execute the support motor operating frequency instruction based on the support frequency converter to drive the support motor to operate;

[0097] Step S30: sending the switching motor operating frequency instruction to the switching inverter based on the supporting inverter so that the switching inverter receives and executes the switching motor operating frequency instruction to drive the switching motor to operate.

[0098] It should be noted that the start command can be issued by the operator in the driver's cab of the crane through the grab control console or operating lever, such as opening and closing in the east-west direction and lifting in the north-south direction; when the supporting frequency converter receives the start command, it starts to run the grab closed-loop control scheme, the supporting motor operating frequency command includes the supporting motor speed output, and the opening and closing motor operating frequency command includes the opening and closing motor speed output; the supporting motor runs according to the supporting motor speed output, drives the transmission device and the drum, pulls or drops the supporting rope to realize the lifting and lowering operation of the grab; the opening and closing motor runs according to the opening and closing motor speed output, drives the transmission device and the drum, pulls or drops the opening and closing rope to realize the opening and closing operation of the grab. In this embodiment, the communication mode between the supporting frequency converter and the opening and closing frequency converter is master-slave communication, the supporting frequency converter is the master, the opening and closing frequency converter is the slave, and the communication protocol can be the protocol of the frequency converter itself, or it can be other communication protocols that can realize data interaction between the two frequency converters.

[0099] As an example, in this embodiment, before step S10, it also includes an initialization configuration process of the grab control system, that is, based on the automatic unit conversion module in the supporting inverter, the pulse / rope length conversion coefficient of the supporting motor and the opening and closing motor is obtained, and based on the grab calibration module in the supporting inverter, the opening bucket position difference and the closing bucket position difference are calibrated.

[0100] As an example, in this embodiment, after step S30, it also includes: dynamically obtaining the support motor pulse and the opening and closing motor pulse from the support encoder and the opening and closing encoder, inputting the support motor pulse and the opening and closing motor pulse and the corresponding pulse / rope length conversion coefficient into the grab calibration module in the support inverter to obtain the support motor position and the opening and closing motor position, and further obtaining the real-time value of the opening.

[0101] As an example, in this embodiment, after step S30, it also includes: calculating the opening change, obtaining the absolute value of the difference between the opening setting value and the opening real-time value, judging whether the opening change is greater than or equal to the absolute value of the difference, and if the opening change is greater than or equal to the absolute value of the difference, gradually reducing the speed output of the opening and closing motor.

[0102] As an example, the grab bucket control method provided in this embodiment can also be directly applied to support the frequency converter, and the grab bucket control method includes the following steps:

[0103] When a start instruction is received, generate and output a support motor operating frequency instruction and an opening / closing motor operating frequency instruction according to the start instruction;

[0104] Execute the support motor operating frequency instruction to drive the support motor connected to the support frequency converter to operate;

[0105] Send the opening / closing motor operating frequency instruction to the opening / closing frequency converter to drive the opening / closing motor connected to the opening / closing frequency converter to operate.

[0106] As an example, the grab control method provided in this embodiment can also be directly applied to the opening / closing frequency converter. The grab control method includes the following steps:

[0107] Receive the opening / closing motor operating frequency instruction generated and output by the support frequency converter according to the start instruction;

[0108] Execute the opening / closing motor operating frequency instruction to drive the opening / closing motor connected to the opening / closing frequency converter to operate.

[0109] In this embodiment, a grab control method is provided, which overcomes the problems of the existing grab control technology that it needs to rely on a host computer or a third controller, the control scheme is complex and costly, it cannot automatically obtain the pulse / rope length conversion coefficient, and it cannot achieve automatic deceleration of the opening / closing bucket without relying on a preset reference value. This embodiment realizes logical operation and control functions based on a support frequency converter integrated with multiple functional modules, without relying on a host computer PLC or a third controller. Only by the encoders installed in the opening / closing motor and the support motor to feedback the position can the grab closed-loop control be realized. Compared with the open-loop control, the opening degree of the grab can be dynamically adjusted in real time according to the real-time opening value converted from the feedback information, ensuring that the grab opening / closing action can be in place at one time, avoiding the operator needing to perform multiple jogging operations to reach the position required for grab opening / closing; at the same time, in this embodiment, a load balancing controller is adopted in the grab closed-loop control to achieve dynamic balance during the lifting of the closed bucket, realizing a precise control effect, improving the efficiency of the crane grab, and effectively reducing the labor intensity of the operator.

[0110] In addition, an embodiment of the present invention also proposes a computer-readable storage medium, which can be set in the grab control system or the crane in the above embodiments. A grab control program is stored on the computer-readable storage medium. When the grab control program is executed by a processor, the grab control method provided in the above embodiments is realized.

[0111] It should be noted that, in this document, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or system comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or system. Without further limitation, an element defined by the statement "comprising one..." does not exclude the existence of additional identical elements in the process, method, article or system comprising such element.

[0112] The serial numbers of the above embodiments of the present invention are for description only and do not represent the superiority or inferiority of the embodiments.

[0113] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-described embodiment methods can be implemented by means of software plus a necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation. Based on such an understanding, the technical solution of the present invention, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium as described above (such as ROM / RAM, magnetic disk, optical disc) and includes several instructions for causing a terminal device (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in various embodiments of the present invention.

[0114] The above are only the preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the description of the present invention and the accompanying drawings, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A grab control system, characterized in that, The grab control system includes: A support mechanism, which includes a support frequency converter and a support motor; An opening and closing mechanism, which includes an opening and closing frequency converter and an opening and closing motor; The support frequency converter is communicatively connected to the opening and closing frequency converter; The opening and closing frequency converter is used to dynamically obtain the state information of the opening and closing motor and send the state information of the opening and closing motor to the support frequency converter; The support frequency converter is used to dynamically obtain the state information of the support motor and receive the state information of the opening and closing motor, generate a support motor operating frequency command and an opening and closing motor operating frequency command based on the state information of the support motor and the opening and closing motor, and execute the support motor operating frequency command to drive the support motor to operate; The support frequency converter is further used to send the opening and closing motor operating frequency command to the opening and closing frequency converter so that the opening and closing frequency converter receives and executes the opening and closing motor operating frequency command to drive the opening and closing motor to operate; The support frequency converter includes: An automatic unit conversion module, which is used to obtain a support motor pulse conversion coefficient according to the support motor pulses in the support motor state information, and obtain an opening and closing motor pulse conversion coefficient according to the opening and closing motor pulses in the opening and closing motor state information.

2. The grab control system according to claim 1, wherein, The grab control system further includes: A support encoder, which is arranged on the motor shaft of the support motor and is communicatively connected to the support frequency converter, and is used to obtain the support motor pulses; An opening and closing encoder, which is arranged on the motor shaft of the opening and closing motor and is communicatively connected to the opening and closing frequency converter, and is used to obtain the opening and closing motor pulses.

3. The grab control system according to claim 1, characterized in that, The support frequency converter further includes: A grab calibration module, which is used to perform calibration according to the support motor pulses, the support motor pulse conversion coefficient, the opening and closing motor pulses, the opening and closing motor pulse conversion coefficient and preset calibration parameters to generate grab position parameters.

4. The grab control system according to claim 3, wherein The support frequency converter further includes: A speed deviation calculation module, which is used to determine an opening bucket reference value and a closing bucket reference value according to the grab position parameters, and generate an opening bucket automatic deceleration scheme and a closing bucket automatic deceleration scheme based on the opening bucket reference value and the closing bucket reference value.

5. A grab control method, the grab control method being applied to the grab control system according to any one of claims 1-4, characterized in that, The grab control method includes the following steps: When a start command is received, generate and output a support motor operating frequency command and an opening and closing motor operating frequency command based on the support frequency converter; Execute the support motor operating frequency command based on the support frequency converter to drive the support motor to operate; Send the opening and closing motor operating frequency command to the opening and closing frequency converter based on the support frequency converter so that the opening and closing frequency converter receives and executes the opening and closing motor operating frequency command to drive the opening and closing motor to operate.

6. A grab control method, characterized in that, The grab control method is applied to the support frequency converter in the grab control system according to any one of claims 1-4. The grab control method includes the following steps: When a start command is received, generate and output a support motor operating frequency command and an opening and closing motor operating frequency command according to the start command; Execute the instruction to support the operating frequency of the motor to drive the operation of the support motor connected to the support frequency converter; Send the instruction for the operating frequency of the opening and closing motor to the opening and closing frequency converter to drive the operation of the opening and closing motor connected to the opening and closing frequency converter.

7. A grab control method, characterized in that, The grab control method is applied to the opening and closing frequency converter in the grab control system according to any one of claims 1-4. The grab control method includes the following steps: Receive the instruction for the operating frequency of the opening and closing motor generated and output by the support frequency converter according to the start instruction; Execute the instruction for the operating frequency of the opening and closing motor to drive the operation of the opening and closing motor connected to the opening and closing frequency converter.

8. A crane, characterized in that, The crane includes: a memory, a processor, and a grab control program stored on the memory and executable on the processor. When the grab control program is executed by the processor, the steps of the grab control method according to any one of claims 5-7 are implemented.

9. A computer-readable storage medium, characterized in that A grab control program is stored on the computer-readable storage medium. When the grab control program is executed by the processor, the steps of the grab control method according to any one of claims 5-7 are implemented.

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