Crane control method, control system, control device and computer-readable storage medium

Abstract

The present application provides a control method, a control system, a control device and a computer-readable storage medium for a crane, wherein the control method comprises: obtaining a working state feature group of a hoisting motor, wherein the working state feature group comprises two or more working state features; comparing the working state feature group of the hoisting motor with a corresponding feature threshold value to determine whether the hoisting motor is in an abnormal state; when it is determined that the hoisting motor is in an abnormal state, starting to cumulatively calculate the duration of the hoisting motor being in the abnormal state, and comparing the duration with a preset time in real time; when the duration reaches the preset time, performing an anti-fall operation, thereby quickly reducing the speed of the hoisting motor to 0, so that the heavy object stops at the current position, thereby effectively avoiding the accident of the heavy object falling to the ground.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of cranes, and in particular to a control method, a control system, a control device, and a computer-readable storage medium for a crane. Background Art

[0002] Benefiting from rapid economic development and the promotion of new prefabricated construction technologies, tower cranes are increasingly used in infrastructure construction. Due to their operational characteristics, such as heavy loads, high lifting heights, large slewing radii, and frequent use in densely populated areas, tower cranes impose strict safety requirements. When the crane's hoist mechanism lowers a load, the load drives the motor, generating power and feeding energy back to the inverter. During this process, the inverter's braking resistor is required to dissipate the excess energy, otherwise the inverter will fail due to overvoltage. When the required energy reaches the braking resistor's power limit—that is, when the required energy reaches its maximum capacity—the inverter activates its internal protection function, extending the deceleration time for the hoist motor. This extended deceleration time is equivalent to adding a certain speed to the original motor speed. The increased speed results in more energy fed back to the inverter, making it even more difficult for the inverter to stop, ultimately leading to overspeed. If the load is close to the ground, the load could crash to the ground at high speed, potentially causing a serious safety accident. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the defect in the prior art that when the energy fed back by the hoisting motor to the inverter is greater than the maximum energy that can be consumed by the braking resistor, the speed of the hoisting motor is out of control, thereby causing the heavy object to fall to the ground at high speed and causing a major safety accident. A control method, control system, control device and computer-readable storage medium for a crane are provided.

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] In a first aspect, an embodiment of the present application provides a control method for a crane, wherein the crane includes a hoisting motor and a frequency converter for controlling the hoisting motor. The control method includes:

[0006] Acquire a working state feature group of the lifting motor, wherein the working state feature group includes two or more working state features;

[0007] Comparing the working state feature group of the lifting motor with the corresponding feature threshold to determine whether the lifting motor is in an abnormal state;

[0008] When it is determined that the lifting motor is in the abnormal state, starting to cumulatively calculate the duration of the lifting motor being in the abnormal state, and comparing the duration with a preset time in real time;

[0009] When the duration reaches the preset time, an anti-fall operation is performed.

[0010] In a possible implementation, the working state feature group includes at least: a current speed of the lifting motor and a current power of the lifting motor, wherein the step of comparing the working state feature group of the lifting motor with a corresponding feature threshold further includes:

[0011] Comparing the current speed of the lifting motor with a preset speed, wherein the preset speed is a negative value,

[0012] The current power of the lifting motor is compared with a preset power, wherein the preset power is a negative value, and the absolute value of the preset power is less than or equal to the maximum power of the braking resistor in the inverter.

[0013] In a possible implementation, a difference between an absolute value of the preset power and a maximum power of a braking resistor in the inverter is greater than 0 and less than or equal to 100W.

[0014] In a possible implementation, the step of determining whether the lifting motor is in an abnormal state includes:

[0015] When the current speed of the lifting motor is less than or equal to the preset speed and the current power of the lifting motor is less than or equal to the preset power, it is determined that the lifting motor is in an abnormal state.

[0016] In a possible implementation, executing the anti-fall operation includes: executing inverter parking.

[0017] In a possible implementation, the crane includes a host computer connected to the frequency converter signal, and the frequency converter parking includes the host computer sending a stop instruction to the frequency converter controlling the hoisting motor, and the frequency converter immediately stops.

[0018] In a possible implementation, the lifting motor has a brake, and when the frequency converter stops, the brake is closed to brake the lifting motor.

[0019] In a possible implementation, the anti-fall operation further includes: outputting fault information, wherein the fault information requires manual unlocking.

[0020] In a possible implementation, the preset time is 200 ms.

[0021] In a second aspect, an embodiment of the present application provides a control system for a crane, the crane including a hoisting motor and a frequency converter for controlling the hoisting motor, the control system including:

[0022] an acquisition module configured to acquire a working state feature group of the lifting motor, wherein the working state feature group includes two or more working state features;

[0023] a judgment module configured to compare the working state feature group of the lifting motor with a corresponding feature threshold value to determine whether the lifting motor is in an abnormal state;

[0024] a time accumulation module configured to, when determining that the lifting motor is in the abnormal state, start accumulating and calculating the duration of the lifting motor being in the abnormal state, and compare the duration with a preset time in real time;

[0025] The control module is configured to execute an anti-fall operation when the duration reaches the preset time.

[0026] In a third aspect, an embodiment of the present application provides a control device for a crane, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-described method when executing the computer program.

[0027] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method described above are implemented.

[0028] The crane control method, control system, control device, and computer-readable storage medium provided by the embodiments of the present application determine whether the hoist motor is in an abnormal state by comparing a set of operating state characteristics of the hoist motor with corresponding characteristic thresholds. When the hoist motor is determined to be in an abnormal state, the duration of the abnormal state is accumulated and calculated to filter out jitter interference. When the duration reaches a preset time, an anti-fall operation is executed, rapidly reducing the hoist motor speed to zero, stopping the load at its current position, and effectively preventing the load from falling to the ground. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The following drawings are only intended to illustrate and explain the present application and do not limit the scope of the present application.

[0030] Figure 1 A schematic diagram of a crane;

[0031] Figure 21 is a power-time curve and a speed-time curve of a hoisting motor without using the control method of the crane of the present application. The solid line represents the actual speed of the hoisting motor, wherein the positive direction represents lifting of a load and the negative direction represents lowering of a load. The dotted line represents the actual power of the hoisting motor, wherein the positive direction represents electric power (i.e., power when lifting a load) and the negative direction represents regenerative power (i.e., power when lowering a load).

[0032] Figure 3 This is a flow chart of a crane control method provided in Example 1 of the present application;

[0033] Figure 4 This is a flow chart of a crane control method provided in Example 2 of the present application;

[0034] Figure 5 It is the power time curve and speed time curve of the lifting motor after using the control method of the crane provided in the embodiment of the present application. The solid line represents the actual speed of the lifting motor, wherein the positive direction is for lifting the heavy object and the negative direction is for lowering the heavy object; the dotted line represents the actual power of the lifting motor, wherein the positive direction is the electric power (i.e., the power when lifting the heavy object) and the negative direction is the regenerative power (i.e., the power when lowering the heavy object).

[0035] Description of reference numerals:

[0036] 10 Tower

[0037] 20 Upper Arm

[0038] 30 Heavy Objects

[0039] 301 Motor speed is less than or equal to the preset speed

[0040] 302 Actual power is less than or equal to the preset power

[0041] 303 and

[0042] 304 The lifting motor is in an abnormal state

[0043] 305 Cumulative calculation of the duration of the abnormal state of the lifting motor

[0044] 306 The duration has reached the scheduled time

[0045] 307 Inverter stop

[0046] 308 Close the brake

[0047] 309 Output fault information DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples. It is apparent that the described embodiments are only a portion of the embodiments of this application, rather than all of them. All other technical solutions derived by those of ordinary skill in the art based on the embodiments in this application fall within the scope of protection of this application.

[0049] Crane refers to a multi-functional lifting machine that can lift heavy objects vertically and transport them horizontally within a certain range. Figure 1 As shown in the figure, a tower crane primarily consists of a slewing mechanism, a luffing mechanism, and a hoisting mechanism. The slewing mechanism controls the boom's rotational motion around the tower, the luffing mechanism controls the trolley's forward and backward motion along the boom, and the hoisting mechanism controls the load's up and down motion, thereby accurately transporting the load to any point in three-dimensional space. The slewing mechanism, luffing mechanism, and hoisting mechanism are each driven by one or more motors, each driven by a frequency converter (VFD). The VFD's input and output signal evaluation and control logic are controlled by a host computer, which is connected to the VFD via a PROFINET network.

[0050] When a crane's hoist mechanism lowers a heavy object, the load drives the motor, causing it to generate electricity and feed energy back to the inverter. The inverter's braking resistor is then needed to dissipate the excess energy, otherwise the inverter will shut down due to overvoltage. When the energy required reaches the braking resistor's power limit—that is, when the energy required reaches the maximum energy it can dissipate—the inverter activates its internal protection function, extending the hoist motor's deceleration time. Extending the deceleration time is equivalent to adding a certain speed to the original motor speed. This increased speed causes the hoist motor to feed more energy back to the inverter, making it even more difficult for the inverter to stop, ultimately leading to overspeed. If the load is close to the ground, it will crash to the ground at high speed, potentially causing a serious safety incident.

[0051] When a crane lowers a heavy object, the power fed back by the hoisting motor to the inverter is the braking power required to be consumed by the inverter's braking resistor. This includes the power required to overcome the gravity of the heavy object and the braking power when the motor decelerates. Therefore, when the crane is lowering a heavy object, the power fed back by the hoisting motor to the inverter is the largest at the moment of deceleration and stopping, that is, the braking power required to be consumed by the inverter's braking resistor is the largest.

[0052] When lowering a heavy object and starting to slow down to a stop, the speed of the lifting motor needs to be reduced to 0 within a certain period of time. The total braking energy consumed by the braking resistor is:

[0053] W 总 =W 重物 +W 减速 2-1

[0054] Where: W 重物 The energy required to overcome the gravity of a heavy object; W 减速 The energy required to decelerate a heavy object.

[0055] W 重物 =mgh 2-2

[0056] Where: m is the mass of the weight; g is the acceleration of the weight; h is the distance the weight is lowered.

[0057]

[0058] Among them: J motor is the moment of inertia of the motor; J is the moment of inertia of the load; n1 is the starting speed; n2 is the speed after braking.

[0059] Figure 2 The power-time curve and speed-time curve of the lifting motor are shown in the figure. The solid line in the figure represents the actual speed of the lifting motor, where the positive direction is lifting the heavy object and the negative direction is lowering the heavy object; the dotted line represents the actual power of the lifting motor, where the positive direction is the electric power (i.e. the power when lifting the heavy object) and the negative direction is the regenerative power (i.e. the power when lowering the heavy object).

[0060] like Figure 2 As shown in the figure, when the weight is lowered and approaches the target position, the lifting motor needs to be decelerated and stopped at point A. According to formula 2-3, at this time, W 减速 Maximum, that is, the regenerative power of the lifting motor is maximum at this time.

[0061] Assume that the maximum power of the braking resistor in the inverter is 15kw. The crane lowers the heavy object at a constant speed. Since the motor speed remains unchanged (n1=n2), it can be known from formula 2-3 that W 减速 = 0. Assume W 重物 =15KW, then W 总 =W 重物 +W 减速 =15kw+0=15kw, that is, the regenerative power is 15kw (equal to the maximum power of the braking resistor). When this energy is fed back to the inverter, the braking resistor can just consume this energy. When the heavy object approaches the target position, it is necessary to slow down the lifting motor and stop it, that is, reduce the speed of the lifting motor to 0 within a certain period of time, as shown in formula 2-3, W 减速 Increase, then W 总>15kW, meaning the regenerative power fed back to the inverter by the hoist motor exceeds the power of the braking resistor. At this point, the inverter activates an internal protection function to limit the motor's regenerative power to 15kW, preventing it from exceeding 15kW. Specifically, the inverter limits the motor's regenerative power by extending the motor's deceleration time. For example, the motor needs to steadily decrease from 1500 rpm to 0 rpm within 15 seconds. Normally, the motor's speed should decrease to 1400 rpm in the first second. Equations 2-1 and 2-3 show that as the motor decelerates, the regenerative power increases. At this point, the regenerative power exceeds 15kW, indicating that the energy fed back to the inverter by the hoist motor exceeds the maximum energy dissipated by the braking resistor. The inverter then activates its internal protection mechanism, extending the motor's deceleration time by adding 20 rpm to the motor's current speed of 1400 rpm, bringing the motor's speed to 1420 rpm. However, the higher the speed of the lifting motor, the faster the weight will descend. At this time, the regenerative power will be even greater, and the regenerative power will be fed back to the inverter. The inverter will continue to activate the internal protection mechanism, which will further extend the deceleration time of the lifting motor, thus causing a vicious cycle and making it impossible to control the speed of the lifting motor. Ultimately, the weight will hit the ground at high speed, which will cause a major safety accident.

[0062] For example, in one accident, when a crane was lowering a heavy object, its lifting motor was running at a constant speed of 1400rpm. When approaching the target position, the lifting motor needed to be decelerated and stopped. At this time, the speed set value of the lifting motor was reduced to 737rpm, but its actual speed did not decrease accordingly. Instead, it accelerated to 2304rpm, and the indicator light of the inverter was still green. The inverter did not stop due to a fault, causing the heavy object to accelerate and fall to the ground.

[0063] Based on the principle of the above-mentioned lifting motor controlling the lowering of heavy objects, the embodiments of the present application provide a control method, a control system, a control device and a computer-readable storage medium for a crane to at least partially solve the above-mentioned technical problems.

[0064] Example 1

[0065] Figure 3 This is a flow chart of the crane control method of embodiment 1 of the present application. Figure 3 As shown, the method includes:

[0066] S101, obtaining a working state feature group of a lifting motor, where the working state feature group includes two or more working state features;

[0067] S102, comparing the working state feature group of the lifting motor with the corresponding feature threshold to determine whether the lifting motor is in an abnormal state;

[0068] S103, when it is determined that the lifting motor is in an abnormal state, starting to cumulatively calculate the duration of the lifting motor being in the abnormal state, and comparing the duration with a preset time in real time;

[0069] S104: When the duration reaches a preset time, perform an anti-fall operation.

[0070] In one possible implementation, the preset time is 200ms. When the duration of the abnormal state reaches the preset time, the anti-fall operation is performed, which can filter out certain interference information such as jumping, thereby improving the accuracy and precision of the control.

[0071] In a possible implementation, executing the anti-fall operation includes: executing inverter parking, and the inverter terminating output.

[0072] In one possible implementation, a crane includes a host computer connected to a frequency converter signal. Frequency converter parking includes the host computer sending a stop command to a frequency converter controlling a hoist motor, causing the frequency converter to immediately stop. Upon receiving the stop command from the host computer, the frequency converter immediately stops outputting.

[0073] In a possible implementation, the lifting motor has a brake. When the frequency converter stops, the brake is closed to brake the lifting motor.

[0074] In one feasible embodiment, the brake is an electromagnetic brake. When the hoist motor is powered, the electromagnetic brake coil is also energized. Under the action of electromagnetic attraction, the armature is attracted, the brake wheel and brake shoe are separated, and the hoist motor operates normally. When the hoist motor is powered off, the electromagnetic brake coil is also de-energized. The armature is separated from the iron core by the tension of the spring, the brake shoe tightly holds the brake wheel, and the hoist motor quickly stops.

[0075] In one possible implementation, the anti-fall operation also includes outputting a fault message, which requires manual unlocking. When the abnormal state persists for a preset time, the inverter stops, halting output, and simultaneously outputs a fault message. This prevents the inverter from restarting, requiring an operator to clear the fault before it can restart, further ensuring the safety of the load.

[0076] Example 2

[0077] Example 2 is a control method for a crane based on Example 1. Figure 3 As shown, the method includes:

[0078] S201, obtaining the current speed and current power of the lifting motor;

[0079] S202, compare the current speed of the lifting motor with a preset speed, where the preset speed is a negative value; compare the current power of the lifting motor with a preset power, where the preset power is a negative value, and the absolute value of the preset power is less than or equal to the maximum power of the braking resistor in the inverter; when the current speed of the lifting motor is less than or equal to the preset speed and the current power of the lifting motor is less than or equal to the preset power, it is determined that the lifting motor is in an abnormal state. For example, the current speed of the lifting motor is V1, the preset speed is V, where the preset speed V is a negative value; the current power of the lifting motor is P 1, , the preset power is P, wherein the preset power P is a negative value; only when V1≤V and P1≤P are satisfied at the same time, can it be determined that the lifting motor is in an abnormal state.

[0080] The actual speed of the hoist motor is positive when lifting a heavy object, and negative when lowering it. The motor's speed remains stable during lifting, but only during lowering can it cause an accident, potentially causing the object to fall to the ground at high speed. Therefore, setting the preset speed V to a negative value eliminates the need for heavy lifting, allowing for precise and targeted crane control.

[0081] In one feasible embodiment, the preset speed is -5, i.e., V = -5. V = -5 can exclude the state of the heavy object being stationary, because when the heavy object is stationary, the actual speed V1 of the lifting motor detected also fluctuates (for example, fluctuates around 0 by 1-2 revolutions), and V = -5 can exclude the stationary state.

[0082] In one possible implementation, the difference between the absolute value of the preset power |P| and the maximum power P2 of the braking resistor in the inverter is greater than 0 and less than or equal to 100W. The difference between the absolute value of the preset power |P| and the maximum power P2 of the braking resistor in the inverter is ΔP = P2 - |P|, where 0 < ΔP ≤ 100W. Assuming the maximum power of the braking resistor is 15,000W, the preset power is -15,000W < P ≤ -14,900W. This setting keeps ΔP within a reasonable range. On the one hand, it prevents the execution of anti-fall operations when ΔP is large (when ΔP is large, the regenerative power of the lifting motor can be fully consumed by the braking resistor of the inverter, preventing the aforementioned accidents of uncontrolled lifting motor speed and heavy objects falling to the ground), which would affect the normal operation of the crane and reduce its operating efficiency. On the other hand, when ΔP is greater than 0, that is, |P| ≠ P2, the anti-fall operation can be executed before the regenerative power of the lifting motor reaches the maximum power that the braking resistor can consume, leaving sufficient buffer time to further ensure the safe operation of the crane.

[0083] S203, when it is determined that the lifting motor is in an abnormal state, starting to cumulatively calculate the duration of the lifting motor being in the abnormal state, and comparing the duration with a preset time in real time;

[0084] S204: When the duration reaches a preset time, perform an anti-fall operation.

[0085] In a possible implementation, executing the anti-fall operation includes: executing inverter parking, and the inverter terminating output.

[0086] In one possible implementation, a crane includes a host computer connected to a frequency converter signal. Frequency converter parking includes the host computer sending a stop command to a frequency converter controlling a hoist motor, causing the frequency converter to immediately stop. Upon receiving the stop command from the host computer, the frequency converter immediately stops outputting.

[0087] In a possible implementation, the lifting motor has a brake. When the frequency converter stops, the brake is closed to brake the lifting motor.

[0088] In one feasible embodiment, the brake is an electromagnetic brake. When the hoist motor is powered, the electromagnetic brake coil is also energized. Under the action of electromagnetic attraction, the armature is attracted, the brake wheel and brake shoe are separated, and the motor operates normally. When the hoist motor is powered off, the electromagnetic brake coil is also de-energized. The armature is separated from the iron core by the tension of the spring, the brake shoe tightly holds the brake wheel, and the motor quickly stops rotating.

[0089] In one possible implementation, the anti-fall operation also includes outputting a fault message, which requires manual unlocking. When the abnormal state persists for a preset time, the inverter stops and ceases output, while simultaneously outputting a fault message. This prevents the inverter from restarting and can only be restarted after an operator has cleared the fault, further ensuring the safety of the load.

[0090] Now combined Figure 4 The control flow of the crane in the second embodiment will be described.

[0091] 301: Obtain the current speed of the lifting motor and compare the current speed of the lifting motor with the preset speed;

[0092] 302: Obtain the current power of the lifting motor and compare the current speed of the lifting motor with the preset power;

[0093] 303: When the current speed of the lifting motor is less than or equal to the preset speed and the current power of the lifting motor is less than or equal to the preset power;

[0094] 304: Determine that the lifting motor is in an abnormal state;

[0095] 305: When it is determined that the lifting motor is in an abnormal state, start accumulating and calculating the duration of the lifting motor being in the abnormal state, and compare the duration with a preset time in real time;

[0096] 306: The duration of the abnormal state of the lifting motor reaches the preset time;

[0097] 307: inverter stop;

[0098] 308: Close the brake;

[0099] 309: Output fault information.

[0100] The crane control method provided in Example 2 is used for the crane's hoist mechanism. When the hoist mechanism is lowering a load, the actual speed and actual power of the hoist motor are both negative. If it is detected that the actual speed of the hoist motor is less than a preset speed of a negative value, and the absolute value of the actual power of the hoist motor is less than or equal to the preset power of a negative value, and persists for a short period of time, the frequency converter stops and the brake closes, rapidly reducing the speed of the hoist motor to zero, thereby stopping the load at its current position. This prevents the load from falling to the ground due to uncontrolled hoist motor speed, effectively avoiding accidents. The frequency converter also outputs a corresponding fault message while stopping, preventing the frequency converter from restarting. The frequency converter is allowed to restart only after the operator resolves the fault, further ensuring the safe operation of the crane.

[0101] Figure 5 It is the power time curve and speed time curve of the lifting motor using the control method of the crane provided in the embodiment of the present application. The solid line represents the actual speed of the lifting motor, wherein the positive direction is for lifting the heavy object and the negative direction is for lowering the heavy object; the dotted line represents the actual power of the lifting motor, wherein the positive direction is the electric power (i.e., the power when lifting the heavy object) and the negative direction is the regenerative power (i.e., the power when lowering the heavy object).

[0102] In this example, the preset power is -15kw and the preset speed is -5rpm.

[0103] like Figure 5 As shown, in the range of B1-B2, the weight is lowered at a constant speed of 2200 rpm. At this time, the required braking power is -8 kW, which does not reach the braking power limit.

[0104] At point B2, the hoisting motor needs to be decelerated and stopped. The regenerative power fed back to the inverter by the hoisting motor is less than -15kw. It is judged that the hoisting motor is in an abnormal state. At this time, the duration of the hoisting motor in the abnormal state is accumulated and calculated.

[0105] At point B3, the duration of the lifting motor in the abnormal state reaches 200ms, and the anti-fall operation is executed, that is, the inverter stops and the brake is closed. At point B4, the actual speed of the lifting motor quickly drops to 0, and the heavy object stops in time, avoiding the accident of the heavy object falling to the ground.

[0106] Depend on Figure 2 and Figure 5 It can be seen that the danger of the lifting motor speed being out of control and the heavy object falling to the ground at high speed will only occur when the lifting mechanism is lowering the heavy object. In the process of the lifting mechanism lowering the heavy object, the actual power and actual speed of the lifting motor are both negative values. Therefore, by comparing the actual speed of the lifting motor with a preset speed of a negative value, and comparing the actual power of the lifting motor with a preset power of a negative value, the size of the preset power is related to the size of the power of the braking resistor in the inverter that drives the lifting motor. Therefore, in the process of lowering the heavy object, before the regenerative power of the lifting motor exceeds the maximum power that the braking resistor can consume, the anti-fall operation is performed, thereby avoiding the speed of the lifting motor from being out of control and causing the heavy object to fall to the ground at high speed, and effectively avoiding the occurrence of accidents. In the process of lifting the heavy object, the actual speed and actual power of the lifting motor are both positive values, so the control method of the present application will not affect its operation.

[0107] Example 3

[0108] Example 3 provides a control system for a crane, the crane including a hoisting motor and a frequency converter for controlling the hoisting motor, the control system including:

[0109] an acquisition module configured to acquire a working state feature group of the lifting motor, the working state feature group including two or more working state features;

[0110] a judgment module configured to compare the working state feature group of the lifting motor with the corresponding feature threshold to determine whether the lifting motor is in an abnormal state;

[0111] a time accumulation module configured to, when determining that the hoisting motor is in an abnormal state, start accumulating and calculating the duration of the hoisting motor being in the abnormal state, and compare the duration with a preset time in real time;

[0112] The control module is configured to execute an anti-fall operation when the duration reaches a preset time.

[0113] Example 4

[0114] Example 4 provides a control device for a crane, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-described method when executing the computer program.

[0115] Example 5 The embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the steps of the method described above are implemented.

[0116] The present invention has been shown and described in detail above through the accompanying drawings and preferred embodiments. However, the present invention is not limited to these disclosed embodiments. Based on the above multiple embodiments, those skilled in the art can know that the code review methods in the above different embodiments can be combined to obtain more embodiments of the present invention, and these embodiments are also within the scope of protection of the present invention.

[0117] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A method for controlling a crane, wherein the crane comprises a lifting motor and a frequency converter for controlling the lifting motor, wherein: The control method includes: Acquire a working state feature group of the lifting motor, wherein the working state feature group includes two or more working state features; the working state feature group includes at least: a current speed of the lifting motor and a current power of the lifting motor; Comparing the working state feature group of the lifting motor with the corresponding feature threshold to determine whether the lifting motor is in an abnormal state; When it is determined that the lifting motor is in the abnormal state, starting to cumulatively calculate the duration of the lifting motor being in the abnormal state, and comparing the duration with a preset time in real time; When the duration reaches the preset time, performing an anti-fall operation; The step of comparing the working state feature group of the lifting motor with the corresponding feature threshold further includes: Comparing the current speed of the lifting motor with a preset speed, wherein the preset speed is a negative value, The current power of the lifting motor is compared with a preset power, wherein the preset power is a negative value, and the absolute value of the preset power is less than or equal to the maximum power of the braking resistor in the inverter.

2. The crane control method according to claim 1, wherein: The difference between the absolute value of the preset power and the maximum power of the braking resistor in the inverter is greater than 0 and less than or equal to 100W.

3. The crane control method according to claim 1, wherein: The step of determining whether the lifting motor is in an abnormal state includes: When the current speed of the lifting motor is less than or equal to the preset speed and the current power of the lifting motor is less than or equal to the preset power, it is determined that the lifting motor is in an abnormal state.

4. The crane control method according to claim 1, wherein: Executing the anti-fall operation includes: executing the inverter stop.

5. The crane control method according to claim 4, wherein: The crane includes a host computer connected to the frequency converter signal, and the frequency converter parking includes the host computer sending a stop instruction to the frequency converter controlling the lifting motor, and the frequency converter stops immediately.

6. The crane control method according to claim 5, wherein: The lifting motor has a brake, and when the frequency converter stops, the brake is closed to brake the lifting motor.

7. The crane control method according to claim 4, wherein: The anti-fall operation also includes: Output fault information, wherein the fault information requires manual unlocking.

8. The crane control method according to claim 1, wherein: The preset time is 200ms.

9. A control system for a crane, comprising a lifting motor and a frequency converter for controlling the lifting motor, characterized in that: The control system includes: An acquisition module is configured to acquire a working state feature group of the lifting motor, wherein the working state feature group includes two or more working state features; the working state feature group includes at least: a current speed of the lifting motor and a current power of the lifting motor; a judgment module configured to compare the working state feature group of the lifting motor with a corresponding feature threshold value to determine whether the lifting motor is in an abnormal state; a time accumulation module configured to, when determining that the lifting motor is in the abnormal state, start accumulating and calculating the duration of the lifting motor being in the abnormal state, and compare the duration with a preset time in real time; a control module configured to execute an anti-fall operation when the duration reaches the preset time; The step of comparing the working state feature group of the lifting motor with the corresponding feature threshold in the judgment module further includes: Comparing the current speed of the lifting motor with a preset speed, wherein the preset speed is a negative value, The current power of the lifting motor is compared with a preset power, wherein the preset power is a negative value, and the absolute value of the preset power is less than or equal to the maximum power of the braking resistor in the inverter.

10. A crane control device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 8 are implemented.

11. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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