Multi-hoist single-hook crane and control method and control system thereof

Abstract

The present application belongs to the crane field, disclose a kind of multi-winch single hook type crane and its control method and control system, wherein the control method includes: determining the first suspension rope section of first winch and the second suspension rope section of second winch respectively produce rope length local variation D1 and rope length local variation D2 relative to before boom retraction when boom retraction;Determine the first release rope section of first winch and the second release rope section of second winch respectively produce rope length total variation D3 and rope length total variation D4 relative to before boom retraction when boom retraction;By regulating and controlling second winch, to maintain rope length compensation deviation D5 in the preset allowable compensation deviation range, satisfy: D5=(D4-D3)‑(D1-D2).The present application makes the length variation of the suspension rope section of each winch tend to be substantially consistent when boom retraction, that is, the length of the suspension rope section of each winch is maintained substantially consistent, so as to ensure hook balance.

Description

Technical Field

[0001] This invention relates to the field of crane technology, specifically to a multi-winch single-hook crane and its control method and control system. Background Technology

[0002] When lifting heavy loads, existing large cranes use multiple winches to simultaneously lift a hook via pulley blocks to accommodate heavy lifting conditions.

[0003] During the operation of a multi-winch single-hook crane, if the hook pulley block becomes misaligned, it will lead to pulley damage and accelerated wear of the wire rope. Furthermore, a misaligned hook pulley block will cause unequal loads on the multiple winches. Consequently, when lifting a heavy object at full load, one winch will inevitably be overloaded, leading to a safety accident and posing a very serious safety hazard.

[0004] The skewness of the hook pulley block can be caused by the extension and retraction of the boom. When the boom extends or retracts, the length of the wire rope segment between the boom head and the hook changes accordingly. However, since the positions of the multiple winches relative to the hinge point at the tail of the boom are not the same, the amount of change in the length of the wire rope segment between the boom head and the hook of each winch is also different when the boom extends or retracts, which will cause the hook pulley block, which was originally in a balanced state, to skew. Summary of the Invention

[0005] In view of at least one of the above-mentioned defects or deficiencies in the prior art, the present invention provides a multi-winch single-hook crane and its control method and control system, which can ensure that the length change of the suspension rope segment of each winch is basically the same when the boom extends or retracts, so as to achieve the purpose of maintaining the balance of the hook in real time.

[0006] To achieve the above objectives, the first aspect of the present invention provides a control method for a multi-winch single-hook crane, comprising:

[0007] Determine the local changes in rope length D1 and D2 of the first suspension rope segment of the first winch and the second suspension rope segment of the second winch respectively during boom extension and retraction relative to before boom extension and retraction;

[0008] Determine the total change in rope length D3 and D4 of the first release rope segment of the first winch and the second release rope segment of the second winch relative to the time before the boom extension and retraction.

[0009] By adjusting the second winch, the rope length compensation deviation D5 is maintained within the preset allowable compensation deviation range, wherein: D5=(D4-D3)-(D1-D2).

[0010] Optionally, determining the local changes in rope length D1 and D2 of the first suspension rope segment of the first winch and the second suspension rope segment of the second winch relative to before the boom extension and retraction includes:

[0011] Obtain the real-time boom length La, the real-time boom angle Ra, and the real-time release rope length L of the winch;

[0012] The real-time rope length Lf of the hoist's suspension rope segment at any given time is calculated based on the real-time boom length La, the real-time angle Ra, the real-time rope length L, and the triangular relationship model constructed based on the hoist position, the boom tail hinge point position, and the boom head position.

[0013] The change in the real-time rope length Lf during boom extension and retraction relative to the time before boom extension and retraction is taken as the local change in the rope length of the hoist's suspension rope segment.

[0014] Optionally, adjusting the second winch to maintain the rope length compensation deviation D5 within a preset allowable compensation deviation range includes:

[0015] When the boom is extending and retracting and the winch is releasing the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the rate of increase of the total rope length change D4 is made less than the rate of increase of the total rope length change D3. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the rate of increase of the total rope length change D4 is made greater than the rate of increase of the total rope length change D3, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0016] Optionally, the control method further includes:

[0017] When the boom is extending and retracting and the winch is releasing the rope, if it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value, the total rope length change D4 will stop changing; or if it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, the total rope length change D3 will stop changing.

[0018] Optionally, adjusting the second winch to maintain the rope length compensation deviation D5 within a preset allowable compensation deviation range includes:

[0019] When the boom is extending and retracting and the winch is retracting the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the rate of decrease of the total rope length change D4 is made greater than the rate of decrease of the total rope length change D3. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the rate of decrease of the total rope length change D4 is made less than the rate of decrease of the total rope length change D3, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0020] Optionally, the control method further includes:

[0021] When the boom is extending and retracting and the winch is retracting the rope, if it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value, the total rope length change D3 will stop changing; or if it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, the total rope length change D4 will stop changing.

[0022] Optionally, adjusting the second winch to maintain the rope length compensation deviation D5 within a preset allowable compensation deviation range includes:

[0023] When the boom is extending or retracting and the winch is not retracting or extending the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the total rope length change D4 is reduced while the total rope length change D3 remains unchanged. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the total rope length change D4 is increased while the total rope length change D3 remains unchanged, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0024] Optionally, the control method further includes:

[0025] When the boom is extending or retracting and the winch is not retracting or extending the rope, the boom attitude change is stopped when it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value or when it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value.

[0026] Optionally, the boom extension includes a boom body extension action that can change the boom length and a hydraulic cylinder extension and retraction action that does not change the boom length.

[0027] A second aspect of the present invention provides a control system for a multi-winch single-hook crane, comprising:

[0028] The boom attitude monitoring assembly is used to monitor changes in boom attitude.

[0029] The first winch monitoring assembly is used to monitor and regulate the working status of the first winch.

[0030] The second winch monitoring assembly is used to monitor and regulate the operating status of the second winch; and

[0031] The processor communicates with the boom attitude monitoring assembly, the first winch monitoring assembly, and the second winch monitoring assembly, and is configured as follows:

[0032] Determine the local changes in rope length D1 and D2 of the first suspension rope segment of the first winch and the second suspension rope segment of the second winch respectively during boom extension and retraction relative to before boom extension and retraction;

[0033] Determine the total change in rope length D3 and D4 of the first release rope segment of the first winch and the second release rope segment of the second winch relative to the time before the boom extension and retraction.

[0034] By adjusting the second winch, the rope length compensation deviation D5 is maintained within the preset allowable compensation deviation range, wherein: D5=(D4-D3)-(D1-D2).

[0035] Optionally, the boom attitude monitoring assembly includes a length monitor and an angle monitor for monitoring the real-time boom length La and real-time angle Ra of the boom, respectively. Both the first winch monitoring assembly and the second winch monitoring assembly include encoders for monitoring the real-time rope length L of the winch's release rope segment, for adjusting the release rope speed of the winch's release rope segment, and for adjusting the take-up rope speed of the winch's release rope segment, as well as a release solenoid valve and a take-up solenoid valve. The processor is further configured to:

[0036] The real-time rope length Lf of the hoist's suspension rope segment at any given time is calculated based on the real-time boom length La, the real-time angle Ra, the real-time rope length L, and the triangular relationship model constructed based on the hoist position, the boom tail hinge point position, and the boom head position.

[0037] The change in the real-time rope length Lf during boom extension and retraction relative to the time before boom extension and retraction is taken as the local change in the rope length of the hoist's suspension rope segment.

[0038] Optionally, the processor is further configured to:

[0039] When the boom is extending and retracting and the winch is releasing the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the rate of increase of the total rope length change D4 less than the rate of increase of the total rope length change D3. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the rate of increase of the total rope length change D4 greater than the rate of increase of the total rope length change D3, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0040] Optionally, the processor is further configured to:

[0041] When the boom is extending and retracting and the winch is releasing the rope, if it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value, the second winch monitoring assembly is adjusted to stop the change of the total rope length change D4. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, the first winch monitoring assembly is adjusted to stop the change of the total rope length change D3.

[0042] Optionally, the processor is further configured to:

[0043] When the boom is extending and the winch is retracting the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the decreasing rate of the total rope length change D4 greater than the decreasing rate of the total rope length change D3. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the decreasing rate of the total rope length change D4 less than the decreasing rate of the total rope length change D3, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0044] Optionally, the processor is further configured to:

[0045] When the boom is extending and retracting and the winch is retracting the rope, if it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value, the first winch monitoring assembly is adjusted to stop the change of the total rope length change D3. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, the second winch monitoring assembly is adjusted to stop the change of the total rope length change D4.

[0046] Optionally, the processor is further configured to:

[0047] When the boom is extending or retracting and the winch is not retracting or extending the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to reduce the total rope length change D4 while keeping the total rope length change D3 unchanged. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to increase the total rope length change D4 while keeping the total rope length change D3 unchanged, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0048] Optionally, the processor is further configured to:

[0049] When the boom is extending or retracting and the winch is not retracting or extending the rope, if it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value or the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, the boom extension or retraction will be stopped.

[0050] A third aspect of the present invention provides a multi-winch single-hook crane, including the control system described above for the multi-winch single-hook crane.

[0051] As can be seen from the above technical solution, the present invention proposes a method to adjust and maintain the balance of the hook based on the change in rope length. When the boom of a multi-winch single-hook crane extends or retracts, the length change of the suspension rope segment of any one winch is used as a benchmark to correct any deviation in the length change of the suspension rope segments of the other winches. This makes the length changes of the suspension rope segments of each winch tend to be basically consistent, thus ensuring the balance of the hook, effectively avoiding damage to the hook pulley block, extending the service life of the winch ropes, and ensuring safe lifting operations.

[0052] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0053] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0054] Figure 1 This is a flowchart illustrating a control method for a multi-winch single-hook crane according to a specific embodiment of the present invention;

[0055] Figure 2 for Figure 1 A flowchart of an optional execution method for step S1 in the process;

[0056] Figure 3 This is a structural schematic diagram of a control system for a multi-winch single-hook crane according to a specific embodiment of the present invention;

[0057] Figures 4 to 6 These are three schematic diagrams illustrating a triangular relationship model constructed based on the winch position, the boom tail hinge point position, and the boom head position, respectively, in a specific embodiment of the present invention. Figure 4 and Figure 5 The real-time angle Ra of the boom in the middle is different. Figure 4 and Figure 6 The real-time boom length La of the boom in the middle is different;

[0058] Figure 7 This is a schematic diagram of a multi-winch single-hook crane according to a specific embodiment of the present invention.

[0059] Explanation of reference numerals in the attached figures:

[0060] 100 Volume One Yang 200 Volume Two Yang

[0061] 300 boom, 400 hook

[0062] 500 processors, 600 human-machine interface

[0063] 101 First suspension rope segment 102 First encoder

[0064] 103 First rope release solenoid valve 104 First rope take-up solenoid valve

[0065] 201 Second suspension rope segment; 202 Second encoder

[0066] 203 Second rope release solenoid valve 204 Second rope take-up solenoid valve

[0067] 301 Length Monitor; 302 Angle Monitor Detailed Implementation

[0068] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0069] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0070] In the embodiments of the present invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positional relationships of the components in relation to the directions shown in the accompanying drawings or in relation to the vertical, perpendicular, or gravitational directions.

[0071] Before describing the present invention in detail with reference to exemplary embodiments, some technical terms that will appear in the following text will be explained.

[0072] Reference Figure 7 A multi-winch single-hook crane includes multiple winches (including a first winch 100 and a second winch 200), a boom 300, and a hook 400. Each winch includes a drum and a rope wound on the drum. The rope segment released outward by rotating the drum is called the release rope segment. The rope segment between the head of the boom 300 and the hook 400 is called the suspension rope segment. For example, the release rope segment of the first winch 100 is the first release rope segment, and its suspension rope segment is the first suspension rope segment 101; the release rope segment of the second winch 200 is the second release rope segment, and its suspension rope segment is the second suspension rope segment 201.

[0073] The change in length of the suspension rope segment relative to its initial position during a change in boom attitude is termed the local change in rope length. If the suspension rope segment becomes longer during a change in boom attitude, the local change in rope length is positive. In this paper, we define this as an increasing local change in rope length, with a longer suspension rope segment equating to a larger local change in rope length. Conversely, if the suspension rope segment becomes shorter during a change in boom attitude, the local change in rope length is negative. In this paper, we define this as a decreasing local change in rope length, with a shorter suspension rope segment equating to a smaller local change in rope length.

[0074] The change in length of the release rope segment relative to its initial position during a change in boom attitude is defined as the total change in rope length. Similarly, if the release rope segment becomes longer during a change in boom attitude, the total change in rope length is positive. In this paper, we define this as an increasing total change in rope length, with a longer release rope segment equating to a larger total change in rope length. Conversely, if the release rope segment becomes shorter during a change in boom attitude, the total change in rope length is negative. In this paper, we define this as a decreasing total change in rope length, with a shorter release rope segment equating to a smaller total change in rope length.

[0075] The present invention will now be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0076] Reference Figure 1 , Figure 2 , Figures 4 to 7 A first exemplary embodiment of the present invention provides a control method for a multi-winch single-hook crane, comprising:

[0077] Step S1: Determine the local rope length changes D1 and D2 of the first suspension rope segment 101 of the first winch 100 and the second suspension rope segment 201 of the second winch 200 respectively relative to the time before the change of the boom posture when the boom posture changes.

[0078] Step S2: Determine the total change in rope length D3 and D4 of the first release rope segment of the first hoist 100 and the second release rope segment of the second hoist 200 relative to the time before the change in the boom posture when the boom posture changes.

[0079] Step S3: Adjust the second winch 200 to maintain the rope length compensation deviation D5 within the preset allowable compensation deviation range, wherein: D5=(D4-D3)-(D1-D2).

[0080] When the boom's posture changes, if the local changes in rope length D1 and D2 are not equal, the hook 400 will shift from balance to skew. To readjust the hook 400 to balance, the deviation between the local changes in rope length D1 and D2 needs to be corrected. Specifically, when performing steps S1 to S3, the difference in rope length change between D1 and D2 is calculated using the local change in rope length D1 as a reference. To readjust the hook to balance, the second winch 200 must be adjusted so that the difference in rope length change between D4 and D3 (D4-D3) essentially cancels out the difference in rope length change D1-D2. In other words, the rope length compensation deviation D5 must be within the preset allowable compensation deviation range. Ideally, the difference in rope length change, D4-D3, should exactly offset the difference in rope length change, D1-D2. In this case, the rope length compensation deviation, D5, is zero, and the hook is in a perfectly balanced state, without any under-correction or over-correction.

[0081] When there are more than two winches, any one winch can be selected as the first winch 100, and the remaining winches can be regarded as the second winches 200. Thus, the difference between the rope length change D1 and the rope length change D2 of each second winch 200 can be canceled by executing steps S1 to S3.

[0082] Therefore, the control method of this exemplary embodiment is a method for adjusting and maintaining hook balance based on the change in rope length. When the boom posture of a multi-winch single-hook crane changes, it can use the change in length of the suspension rope segment of any one winch as a benchmark to correct the deviation of the length change of the suspension rope segments of the other winches, so that the length changes of the suspension rope segments of each winch tend to be basically consistent, that is, to keep the length of the suspension rope segments of each winch basically consistent, thereby ensuring hook balance, effectively avoiding damage to the hook pulley block, extending the service life of the winch rope, and ensuring safe lifting operations.

[0083] Since the control method of this exemplary embodiment can be used to maintain the balance of the hook in both cases with two or more winches, for the sake of simplicity, the following description is based on the case with two winches, and other specific embodiments in this exemplary embodiment are further introduced. These specific embodiments are also applicable to cases with more than two winches.

[0084] It should also be noted that the changes in boom attitude referred to in this article include boom luffing and / or boom extension, that is, changes in the real-time angle Ra of boom 300, changes in the real-time boom length La of boom 300, and combined changes in the real-time angle Ra and real-time boom length La of boom 300.

[0085] For single-cylinder pin-type cranes, the extension and retraction of the boom requires both boom body extension / retraction and hydraulic cylinder retraction / finding action. That is, after each boom section is extended / retracted, the hydraulic cylinder must locate the next boom section to be extended / retracted. During the boom body extension / retraction action, the boom length changes; during the hydraulic cylinder retraction / finding action, the boom length remains unchanged.

[0086] When performing the hydraulic cylinder telescopic boom-finding action, although the boom length will not change, if the speed of the boom telescopic action in the previous stage is too fast, causing the D5 to change too quickly, it may result in D5 not being completely corrected to be within the preset allowable compensation deviation range. That is, the hook 400 may still have a certain degree of skew. Therefore, when performing the hydraulic cylinder telescopic boom-finding action, it is also necessary to execute the control method of this exemplary embodiment to ensure that the hook can maintain balance.

[0087] All the inventive concepts described herein are applicable to different boom posture changes.

[0088] Furthermore, this exemplary embodiment does not limit the specific means of obtaining the local change in rope length D1, the local change in rope length D2, the total change in rope length D3, and the total change in rope length D4.

[0089] For example, an encoder can be installed in the drum of the winch to monitor the real-time rope length L of the release rope segment. By calculating the difference between the real-time rope length L of the release rope segment when the boom attitude changes and the real-time rope length L before the boom attitude change, the total change in rope length of the release rope segment can be obtained. Moreover, based on the monitoring principle and installation position of the encoder, the accuracy of this method of obtaining the total change in rope length can be guaranteed to be high and will not be affected by changes in boom attitude.

[0090] However, the length of the suspension rope segment is directly affected by changes in the boom's attitude. When the boom's attitude changes, in addition to directly causing changes in the length of the suspension rope segment, it is also difficult to avoid causing some swaying in the suspension rope segment. Therefore, if a sensor is installed on the suspension rope segment to directly measure its length, or even if a sensor not installed on the suspension rope segment is used to directly measure its length, the monitoring data may deviate significantly from the actual situation under unstable conditions such as swaying of the suspension rope segment. This may result in a large error when calculating the difference in rope length change D1-D2, ultimately leading to incorrect correction or no correction. Therefore, this method of obtaining the local change in rope length has low reliability and is not conducive to implementation and application.

[0091] To address the aforementioned issues, the control method of this exemplary embodiment provides a method that can take into account the impact of boom posture changes on the suspension rope segment, so as to accurately obtain the local change in rope length of the suspension rope segment under different boom posture changes. Specifically, this method is an optimization of step S1.

[0092] Specifically, refer to Figure 2 , Figures 4 to 7 Step S1 may include:

[0093] Step S11: Obtain the real-time boom length La, the real-time angle Ra of the boom 300, and the real-time rope length L of the release rope segment of the winch;

[0094] Step S12: Calculate the real-time rope length Lf of the hoist's suspension rope segment at any given time based on the real-time boom length La, real-time angle Ra, real-time rope length L, and the triangular relationship model constructed based on the hoist position, the boom tail hinge point position, and the boom head position.

[0095] Step S13: The change in real-time rope length Lf during boom posture change relative to before boom posture change is taken as the local change in rope length of the hoist's suspension rope segment.

[0096] As shown in the diagram, the real-time arm length La, real-time angle Ra, and real-time rope length Lf are also specific parameters involved in constructing the triangular relationship model in step S12. The specific definitions of each parameter in this triangular relationship model are as follows:

[0097] The real-time angle Ra between the boom and the horizontal line, the preset angle Rb between the center line connecting the winch and the center of the boom tail hinge and the horizontal line, the real-time angle Rc between the center line connecting the winch and the center of the boom tail hinge and the boom, the real-time boom length La, the center distance Lb between the winch and the boom tail hinge, the vertical distance Lc between the winch and the horizontal line, the horizontal distance Ld between the winch and the boom tail hinge, the real-time rope length Le of the release rope segment located between the winch and the boom head, and the real-time rope length Lf of the suspension rope segment.

[0098] The following mathematical formula is used to calculate the real-time rope length Lf:

[0099] (1) Lc and Ld are known hoist position parameters. Since Lb, Lc, and Ld are the three sides of a right triangle, we can know from the Pythagorean theorem that: Lb = √(Lc) 2 +Ld 2 COSRb = Ld / Lb;

[0100] (2) Using the inverse trigonometric function: Rb = ARCCOS(COSRb);

[0101] (3) Ra can be directly monitored by the angle monitor. If the winch is higher than the horizontal line passing through the tail hinge point of the boom, Rc = 180° - Ra - Rb. If the winch is lower than the horizontal line passing through the tail hinge point of the boom, Rc = 180° - Ra + Rb.

[0102] (4) Rc is the angle between La and Lb, and Le, La, and Lb can form a trigonometric function. La can be directly monitored by a length monitor. Therefore, by the Law of Cosines: Le = √(La 2 |Lb 2 2LaLbCOSRc);

[0103] (5) The real-time rope length L of the release rope segment can be directly monitored by the encoder set in the winch. By calculating the difference: Lf = L - Le, the real-time rope length Lf of the suspension rope segment can be determined.

[0104] As can be seen from the above derivation process, when the boom posture changes, due to boom luffing and / or boom extension and retraction, the real-time boom length La and / or real-time angle Ra change accordingly, causing the above triangular relationship to change, which in turn leads to the change of the real-time rope length Lf of the suspension rope segment.

[0105] Regardless of the boom attitude change method, as long as the real-time boom length La, real-time angle Ra, and real-time rope length L are obtained, based on the mathematical relationship in the above derivation process, the real-time rope length Lf at any time can be calculated, including the real-time rope length Lf when the boom attitude changes and the real-time rope length Lf before the boom attitude change. Thus, by calculating the difference, the change in real-time rope length Lf during the boom attitude change relative to before the boom attitude change can be determined. This change is the local change in rope length of the suspended rope segment during the boom attitude change relative to before the boom attitude change (e.g., local rope length change D1 and local rope length change D2).

[0106] As can be seen, when performing steps S11 to S13, the real-time rope length Lf does not need to be directly measured by sensors. Instead, it is indirectly obtained by determining the real-time boom length La, real-time angle Ra, and real-time rope length L. Consequently, the accuracy of the length detectors, angle monitors, and encoders that can be used is not affected by changes in boom posture, avoiding incorrect or uncorrected situations. This results in high reliability and control precision, and ease of implementation. Furthermore, the accuracy of the real-time rope length Lf is not affected by the relative positions of the multiple winches. Therefore, the method described in steps S11 to S13 does not impose any restrictions on the arrangement of the winches.

[0107] The following sections provide detailed explanations on how to specifically control the second winch 200 under the following conditions: boom attitude change + winch rope release, boom attitude change + winch rope retraction, and boom single-action. The boom single-action condition refers to a condition where only the boom moves without winch rope release or retraction, i.e., simple boom luffing, boom telescoping, or boom luffing + telescoping. The logic for controlling the second winch 200 is the same under all three boom single-action conditions.

[0108] Working Condition 1: Boom posture change + winch rope release

[0109] In this embodiment of the operating condition, step S3 may include:

[0110] When it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, it indicates that the current total rope length change D4 is too large. The total rope length change D4 needs to be reduced so that the rope length change difference D4-D3 is reduced. However, due to the current working condition of the winch releasing the rope, the lengths of the first and second release rope segments are constantly increasing. Therefore, the total rope length change D4 and the total rope length change D3 are constantly increasing. At this time, in order to reduce the rope length change difference D4-D3, the rate of increase of the total rope length change D4 must be less than the rate of increase of the total rope length change D3. That is, the second winch 200 is adjusted so that its rope release speed is less than the rope release speed of the first winch 100 until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0111] Alternatively, when it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, it indicates that the current total rope length change D4 is too small, and the total rope length change D4 needs to be increased so that the rope length change difference D4-D3 increases. However, since the lengths of the first and second release rope segments are constantly increasing under the current working conditions, both the total rope length change D4 and the total rope length change D3 are constantly increasing. To increase the rope length change difference D4-D3, the rate of increase of the total rope length change D4 must be greater than the rate of increase of the total rope length change D3. That is, the second winch 200 is adjusted so that its rope release speed is greater than that of the first winch 100, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0112] To address emergency situations (dangerous situations), control methods may further include:

[0113] When it is determined that the rope length compensation deviation D5 is greater than the preset limit positive deviation value, it indicates that the current total rope length change D4 is seriously excessive. At this time, even if the rope release speed of the second winch 200 is adjusted to the slowest (but not zero), it is not possible to quickly bring the rope length compensation deviation D5 into the allowable compensation deviation range to eliminate the current emergency. Therefore, it is necessary to activate the emergency handling mechanism and directly control the second winch 200 to stop releasing the rope, so that the total rope length change D4 stops changing. In this way, while the total rope length change D3 continues to increase, the rope length change difference D4-D3 is reduced as quickly as possible.

[0114] Alternatively, if it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, it means that the current total rope length change D4 is seriously too small. At this time, even if the rope release speed of the second winch 200 is adjusted to the fastest, it is not possible to quickly bring the rope length compensation deviation D5 into the allowable compensation deviation range to eliminate the current emergency. Therefore, it is necessary to activate the emergency handling mechanism and directly control the first winch 100 to stop releasing the rope, so that the total rope length change D3 stops changing. Thus, while the total rope length change D4 continues to increase, the rope length change difference D4-D3 increases at the fastest speed.

[0115] Working Condition 2: Boom posture change + winch rope winding

[0116] In this embodiment of the operating condition, step S3 may include:

[0117] When it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, it indicates that the current total rope length change D4 is too large. The total rope length change D4 needs to be reduced so that the rope length change difference D4-D3 is reduced. However, due to the current working condition of the winch taking in the rope, the lengths of the first and second release rope segments are constantly shortening. Therefore, the total rope length change D4 and the total rope length change D3 are constantly decreasing. At this time, in order to reduce the rope length change difference D4-D3, the rate of decrease of the total rope length change D4 must be greater than the rate of decrease of the total rope length change D3. That is, the second winch 200 is adjusted so that its rope taking speed is greater than the rope taking speed of the first winch 100, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0118] Alternatively, when it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, it indicates that the current total rope length change D4 is too small, and the total rope length change D4 needs to be increased so that the rope length change difference D4-D3 increases. However, since the lengths of the first and second release rope segments are constantly decreasing during the current working condition, both the total rope length change D4 and the total rope length change D3 are constantly decreasing. In order to increase the rope length change difference D4-D3, the rate of decrease of the total rope length change D4 must be less than the rate of decrease of the total rope length change D3. That is, the second winch 200 is adjusted so that its rope winding speed is less than the rope winding speed of the first winch 100, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0119] To address emergency situations (dangerous situations), control methods may further include:

[0120] When it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value, it indicates that the current total rope length change D4 is seriously too large. At this time, even if the rope winding speed of the second winch 200 is adjusted to the fastest, it is not possible to quickly bring the rope length compensation deviation D5 into the allowable compensation deviation range to eliminate the current emergency. Therefore, it is necessary to activate the emergency handling mechanism and directly control the first winch 100 to stop releasing the rope, so that the total rope length change D3 stops changing. Thus, while the total rope length change D4 continues to decrease, the rope length change difference D4-D3 decreases at the fastest speed.

[0121] Alternatively, if it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, it means that the current total rope length change D4 is seriously too small. At this time, even if the rope winding speed of the second winch 200 is adjusted to the slowest (but not zero), it is not possible to quickly bring the rope length compensation deviation D5 into the allowable compensation deviation range to quickly eliminate the current emergency. Therefore, it is necessary to activate the emergency handling mechanism and directly control the second winch 200 to stop releasing the rope, so that the total rope length change D4 stops changing. Thus, while the total rope length change D3 continues to decrease, the rope length change difference D4-D3 increases at the fastest speed.

[0122] Operating Condition 3: Single-action boom (only boom movement without winch rope winding or unwinding)

[0123] In this embodiment of the operating condition, step S3 may include:

[0124] When it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, since there is no hoisting rope release or take-up action in this working condition, the lengths of the first and second release rope segments remain unchanged. Therefore, the total rope length change D4 and the total rope length change D3 are both zero. However, considering that there is still a situation where the total rope length change D4 is too large, it indicates that the current local rope length change D2 is actually too large than the local rope length change D1 (this conclusion can be deduced using the case where the upper and lower thresholds of the allowable compensation deviation range are both zero, which is easier to understand mathematically, because D1 < D2 can be derived from D5 > 0). Therefore, it is necessary to adjust the second hoist 200 to perform the rope release action while keeping the first hoist 100 stopped, so that the total rope length change D4 decreases and the total rope length change D3 remains unchanged, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0125] Alternatively, when it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, since there is no hoisting rope release or release action in this working condition, the lengths of the first and second release rope segments remain unchanged. Therefore, the total rope length change D4 and the total rope length change D3 are both zero. However, considering that there is still a situation where the total rope length change D4 is too small, it indicates that the current local rope length change D2 is actually too small compared to the local rope length change D1 (this conclusion can be deduced using the case where the upper and lower thresholds of the allowable compensation deviation range are both zero, which is easier to understand mathematically, because D1 > D2 can be derived from D5 < 0). Therefore, it is necessary to adjust the second hoist 200 to perform the rope release action while keeping the first hoist 100 stationary, so that the total rope length change D4 increases while keeping the total rope length change D3 unchanged, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0126] To address emergency situations (dangerous situations), control methods may further include:

[0127] When it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value, since there is no hoisting rope release or retraction action in this working condition, the lengths of the first and second release rope segments remain unchanged. Therefore, the total rope length change D4 and the total rope length change D3 are both zero. However, considering that there is still a situation where the total rope length change D4 is significantly larger than the current situation, it indicates that the actual local rope length change D2 is significantly larger than the local rope length change D1. At this time, even if the second hoist 200 is adjusted to perform the rope retraction action and the retraction speed is adjusted to the fastest, it is not possible to quickly bring the rope length compensation deviation D5 within the allowable compensation deviation range to eliminate the current emergency situation. Therefore, it is necessary to activate the emergency handling mechanism to control and stop the change of boom attitude, that is, to control the boom not to perform any actions that will cause attitude change.

[0128] Alternatively, when it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, since there is no hoisting rope release or retraction action in this working condition, the lengths of the first and second release rope segments remain unchanged. Therefore, the total rope length change D4 and the total rope length change D3 are both zero. However, considering that there is still a situation where the total rope length change D4 is significantly too small, it indicates that the actual local rope length change D2 is significantly smaller than the local rope length change D1. At this time, even if the second hoist 200 is adjusted to perform the rope release action and the rope release speed is adjusted to the fastest, it is not possible to quickly bring the rope length compensation deviation D5 into the allowable compensation deviation range to eliminate the current emergency situation. Therefore, it is necessary to activate the emergency handling mechanism to control and stop the change of boom attitude, that is, to control the boom not to perform any actions that will cause attitude change.

[0129] In addition to the above-mentioned conditions one to three, which are emergency situations (dangerous situations) due to hook misalignment, the control method of this exemplary embodiment also includes measures to deal with conditions four and five, which are other types of emergency situations (dangerous situations).

[0130] Operating Condition 4: Hook Overwind

[0131] In this embodiment of the operating condition, the control method may further include:

[0132] When the hook becomes over-wound (i.e., the hook is too close to the boom head) due to excessive rope winding of the winch, excessive boom sway (i.e., the real-time angle Ra is too small), or excessive rope winding of the winch and excessive boom sway, the corresponding actions are to stop all rope winding of the winch, stop boom sway, or stop all rope winding of the winch and stop boom sway, respectively.

[0133] Condition 5: Over-extension of the hook

[0134] In this embodiment of the operating condition, the control method may further include:

[0135] If the hook is over-released due to excessive release of the rope by the winch (i.e., the suspended rope section is too long, causing the hook to be too close to the ground), execute the rope release action to stop all winches.

[0136] In general, the control method of this exemplary embodiment has corresponding ways to adjust the second winch 200 to maintain the balance of the hook for non-emergency situations in working conditions one to three. For emergency situations (dangerous situations), including emergency situations (dangerous situations) in working conditions one to three, working conditions four and five, the first winch 100, the second winch 200 or the boom can be controlled to stop moving, so as to avoid excessive hook deflection, hook overwinding and hook overunwinding, and effectively ensure safe lifting operations.

[0137] Reference Figures 3 to 7 The second exemplary embodiment of the present invention also provides a control system for a multi-winch single-hook crane, which can execute the aforementioned control method and obtain all the technical effects of the control method accordingly. Therefore, the content already described above will not be repeated below, but only the differences will be introduced.

[0138] Specifically, the control system includes:

[0139] The boom attitude monitoring assembly is used to monitor changes in boom attitude.

[0140] The first hoist monitoring assembly is used to monitor and regulate the working status of the first hoist 100;

[0141] The second hoist monitoring assembly is used to monitor and regulate the operating status of the second hoist 200; and

[0142] The processor 500 communicates with the boom attitude monitoring assembly, the first winch monitoring assembly, and the second winch monitoring assembly to acquire information on boom attitude changes, the operating status of the first winch 100, and the operating status of the second winch 200. It can also regulate the first winch 100 and the second winch 200. Maintaining hook balance during boom attitude changes is primarily achieved through the processor's overall control. The processor 500 is configured as follows:

[0143] Determine the local rope length changes D1 and D2 of the first suspension rope segment 101 of the first hoist 100 and the second suspension rope segment 201 of the second hoist 200 relative to the time before the change of the boom posture when the boom posture changes.

[0144] Determine the total change in rope length D3 and D4 of the first release rope segment of the first hoist 100 and the second release rope segment of the second hoist 200 relative to the time before the change in the attitude of the boom when the attitude of the boom changes.

[0145] By adjusting the second winch 200, the rope length compensation deviation D5 is maintained within the preset allowable compensation deviation range, where: D5=(D4-D3)-(D1-D2).

[0146] The control system of this exemplary embodiment executes the aforementioned control method, which can achieve fully automated control without manual operation, reducing the difficulty of operation, and providing higher control accuracy and better control quality.

[0147] Furthermore, the boom attitude monitoring assembly may include a length monitor 301 for monitoring the real-time boom length La and an angle monitor 302 for monitoring the real-time boom angle Ra. Both the length monitor 301 and the angle monitor 302 can be directly mounted on the boom. The monitoring accuracy of these two monitors is not easily affected by changes in the boom attitude, and the monitoring results are reliable.

[0148] Both the first and second winch monitoring assemblies include an encoder for monitoring the real-time rope length L of the winch's release rope segment, a release solenoid valve for adjusting the release speed of the winch's release rope segment, and a take-up solenoid valve for adjusting the take-up speed of the winch's release rope segment.

[0149] The encoder can be mounted on the winch drum via a coupling, rotating concentrically with the drum to send the acquired drum position and frequency signals to the processor 500. The processor 500 analyzes and processes the data to determine the real-time rope length L. The rope-releasing solenoid valve controls the winch's rope-releasing speed based on the magnitude of the control current; a larger control current results in a faster rope-releasing speed, and a smaller control current results in a slower rope-releasing speed. Similarly, the rope-retracting solenoid valve controls the winch's rope-retracting speed based on the magnitude of the control current; a larger control current results in a faster rope-retracting speed, and a smaller control current results in a slower rope-retracting speed.

[0150] More specifically, the encoder of the first winch monitoring assembly is the first encoder 102, the rope release solenoid valve of the first winch monitoring assembly is the first rope release solenoid valve 103, and the rope take-up solenoid valve of the first winch monitoring assembly is the first take-up solenoid valve 104. The encoder of the second winch monitoring assembly is the second encoder 202, the rope release solenoid valve of the second winch monitoring assembly is the second rope release solenoid valve 203, and the rope take-up solenoid valve of the second winch monitoring assembly is the second take-up solenoid valve 204.

[0151] Based on the composition of the above control system, the processor 500 can also be configured as follows:

[0152] The real-time rope length Lf of the hoist's suspended rope segment at any given time is calculated based on the real-time boom length La, real-time angle Ra, real-time rope length L, and a triangular relationship model constructed based on the hoist position, the boom tail hinge point position, and the boom head position.

[0153] The change in real-time rope length Lf relative to the state before the change in boom attitude is taken as the local change in rope length of the hoist's suspension rope segment.

[0154] By pre-storing the computational logic involved in (1) to (5) of the aforementioned control method in the processor 500, when the processor 500 receives information on real-time boom length La, real-time angle Ra, and real-time rope length L, it can calculate the local change in rope length of the suspended rope segment relative to the time before the boom posture change when the boom posture changes.

[0155] In addition, to adapt to different boom posture changes, when the boom is luffing but not extending, the boom posture monitoring assembly is used to monitor the real-time angle Ra of the boom; or, when the boom is extending or retracting but not luffing, the boom posture monitoring assembly is used to monitor the real-time boom length La of the boom; or, when the boom is both extending and luffing, the boom posture monitoring assembly is used to monitor the combined changes of the real-time angle Ra and the real-time boom length La of the boom.

[0156] For the first working condition mentioned above (boom posture change + winch rope release), the processor 500 can also be configured as follows:

[0157] When the boom posture changes and the winch releases the rope, if the rope length compensation deviation D5 is determined to be greater than the upper threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the rate of increase of the total rope length change D4 less than the rate of increase of the total rope length change D3. Alternatively, if the rope length compensation deviation D5 is determined to be less than the lower threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the rate of increase of the total rope length change D4 greater than the rate of increase of the total rope length change D3, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0158] Furthermore, to respond to emergencies (dangerous situations), the processor 500 can also be configured as follows:

[0159] When the boom posture changes and the winch releases the rope, if the rope length compensation deviation D5 is determined to be greater than the preset limit compensation positive deviation value, the second winch monitoring assembly is adjusted to stop the total rope length change D4 from changing. Alternatively, if the rope length compensation deviation D5 is determined to be less than the preset limit compensation negative deviation value, the first winch monitoring assembly is adjusted to stop the total rope length change D3 from changing.

[0160] For the second working condition mentioned above (boom posture change + winch rope release), the processor 500 can also be configured as follows:

[0161] When the boom posture changes and the winch is retracting the rope, if the rope length compensation deviation D5 is determined to be greater than the upper threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the decreasing rate of the total rope length change D4 greater than the decreasing rate of the total rope length change D3. Alternatively, if the rope length compensation deviation D5 is determined to be less than the lower threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the decreasing rate of the total rope length change D4 less than the decreasing rate of the total rope length change D3, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0162] Furthermore, to respond to emergencies (dangerous situations), the processor 500 can also be configured as follows:

[0163] When the boom posture changes and the winch is winding up the rope, if the rope length compensation deviation D5 is determined to be greater than the preset limit compensation positive deviation value, the first winch monitoring assembly is adjusted to stop the total rope length change D3 from changing. Alternatively, if the rope length compensation deviation D5 is determined to be less than the preset limit compensation negative deviation value, the second winch monitoring assembly is adjusted to stop the total rope length change D4 from changing.

[0164] For the aforementioned working condition three (single-action boom), the processor 500 can also be configured as follows:

[0165] When the boom posture changes and the winch does not retract or extend the rope, if the rope length compensation deviation D5 is determined to be greater than the upper threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to reduce the total rope length change D4 while keeping the total rope length change D3 unchanged. Alternatively, if the rope length compensation deviation D5 is determined to be less than the lower threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to increase the total rope length change D4 while keeping the total rope length change D3 unchanged, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

[0166] Furthermore, to respond to emergencies (dangerous situations), the processor 500 can also be configured as follows:

[0167] When the boom posture changes and the winch does not retract or extend the rope, if the rope length compensation deviation D5 is determined to be greater than the preset limit compensation positive deviation value or the rope length compensation deviation D5 is determined to be less than the preset limit compensation negative deviation value, the boom posture change will be stopped.

[0168] For the fourth working condition mentioned above (hook overwind), the processor 500 can also be configured as follows:

[0169] When the hook becomes over-wound (i.e., the hook is too close to the boom head) due to excessive rope winding of the winch, excessive boom sway (i.e., the real-time angle Ra is too small), or excessive rope winding of the winch and excessive boom sway, the corresponding actions are to stop all rope winding of the winch, stop boom sway, or stop all rope winding of the winch and stop boom sway, respectively.

[0170] For the aforementioned working condition five (hook over-release), the processor 500 can also be configured as follows:

[0171] If the hook is over-released due to excessive release of the rope by the winch (i.e., the suspended rope section is too long, causing the hook to be too close to the ground), execute the rope release action to stop all winches.

[0172] To enable human-machine interaction, a human-machine interface 600 can be installed in the control system. This human-machine interface 600 communicates with the processor 500 and can output different function activation signals (such as the activation signal for the self-correction function to maintain hook balance when the boom posture changes). It can also display the real-time status of the crane during operation. Furthermore, in case of emergencies (including emergencies in conditions one to three, conditions four, and condition five), the human-machine interface 600 can also provide relevant alarms and shutdown instructions, informing operators of the reasons for shutdown and suggested measures, ensuring crane safety and greatly improving safety.

[0173] A third exemplary embodiment of the present invention also provides a multi-winch single-hook crane, which includes the control system for the multi-winch single-hook crane described above. Obviously, it has all the technical effects brought about by the control system, which will not be repeated here.

[0174] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0175] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.

[0176] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. A control method for a multi-winch single-hook crane, comprising: Determine the local changes in rope length D1 and D2 of the first suspension rope segment (101) of the first winch (100) and the second suspension rope segment (201) of the second winch (200) respectively during boom extension and retraction, relative to before boom extension and retraction. Determine the total change in rope length D3 and D4 of the first release rope segment of the first winch (100) and the second release rope segment of the second winch (200) relative to the time before the boom extension and retraction, respectively; By adjusting the second winch (200), the rope length compensation deviation D5 is maintained within the preset allowable compensation deviation range, wherein: D5 = (D4 - D3) - (D1 - D2). The method of adjusting the second winch (200) to maintain the rope length compensation deviation D5 within the preset allowable compensation deviation range includes: When the boom is extending and retracting and the winch is releasing the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the rate of increase of the total rope length change D4 is made less than the rate of increase of the total rope length change D3. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the rate of increase of the total rope length change D4 is made greater than the rate of increase of the total rope length change D3, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

2. The control method for a multi-winch single-hook crane according to claim 1, wherein, The determination of the local changes in rope length D1 and D2 of the first suspension rope segment (101) of the first winch (100) and the second suspension rope segment (201) of the second winch (200) during boom extension and retraction relative to before boom extension and retraction includes: Obtain the real-time boom length La, the real-time boom angle Ra, and the real-time release rope length L of the winch; The real-time rope length Lf of the hoist's suspension rope segment at any given time is calculated based on the real-time boom length La, the real-time angle Ra, the real-time rope length L, and the triangular relationship model constructed based on the hoist position, the boom tail hinge point position, and the boom head position. The change in the real-time rope length Lf during boom extension and retraction relative to the time before boom extension and retraction is taken as the local change in the rope length of the hoist's suspension rope segment.

3. The control method for a multi-winch single-hook crane according to claim 1, wherein, The control method further includes: When the boom is extending and retracting and the winch is releasing the rope, if it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value, the total rope length change D4 will stop changing; or if it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, the total rope length change D3 will stop changing.

4. The control method for a multi-winch single-hook crane according to claim 2, wherein, Maintaining the rope length compensation deviation D5 within a preset allowable compensation deviation range by adjusting the second winch (200) includes: When the boom is extending and retracting and the winch is retracting the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the rate of decrease of the total rope length change D4 is made greater than the rate of decrease of the total rope length change D3. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the rate of decrease of the total rope length change D4 is made less than the rate of decrease of the total rope length change D3, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

5. The control method for a multi-winch single-hook crane according to claim 4, wherein, The control method further includes: When the boom is extending and retracting and the winch is retracting the rope, if it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value, the total rope length change D3 will stop changing; or if it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, the total rope length change D4 will stop changing.

6. The control method for a multi-winch single-hook crane according to claim 2, wherein, Maintaining the rope length compensation deviation D5 within a preset allowable compensation deviation range by adjusting the second winch (200) includes: When the boom is extending or retracting and the winch is not retracting or extending the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the total rope length change D4 is reduced while the total rope length change D3 remains unchanged. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the total rope length change D4 is increased while the total rope length change D3 remains unchanged, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

7. The control method for a multi-winch single-hook crane according to claim 6, wherein, The control method further includes: When the boom is extending or retracting and the winch is not retracting or extending the rope, the boom attitude change is stopped when it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value or when it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value.

8. The control method for a multi-winch single-hook crane according to any one of claims 1 to 7, wherein, The boom extension and retraction includes a boom body extension and retraction action that can change the boom length and a hydraulic cylinder extension and retraction boom-finding action that does not change the boom length.

9. A control system for a multi-winch single-hook crane, comprising: The boom attitude monitoring assembly is used to monitor changes in boom attitude. The first hoist monitoring assembly is used to monitor and regulate the working status of the first hoist (100); The second hoist monitoring assembly is used to monitor and regulate the working status of the second hoist (200); and The processor (500) communicates with the boom attitude monitoring assembly, the first winch monitoring assembly, and the second winch monitoring assembly, and is configured as follows: Determine the local changes in rope length D1 and D2 of the first suspension rope segment (101) of the first winch (100) and the second suspension rope segment (201) of the second winch (200) respectively during boom extension and retraction relative to before boom extension and retraction; Determine the total change in rope length D3 and D4 of the first release rope segment of the first winch (100) and the second release rope segment of the second winch (200) relative to the time before the boom extension and retraction, respectively; By adjusting the second winch (200), the rope length compensation deviation D5 is maintained within the preset allowable compensation deviation range, wherein: D5 = (D4 - D3) - (D1 - D2). The processor (500) is also configured to: When the boom is extending and retracting and the winch is releasing the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the rate of increase of the total rope length change D4 less than the rate of increase of the total rope length change D3. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the rate of increase of the total rope length change D4 greater than the rate of increase of the total rope length change D3, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

10. The control system for a multi-winch single-hook crane according to claim 9, wherein, The boom attitude monitoring assembly includes a length monitor (301) and an angle monitor (302) for monitoring the real-time boom length La and real-time angle Ra of the boom, respectively. Both the first and second winch monitoring assemblies include encoders for monitoring the real-time rope length L of the winch's release rope segment, for adjusting the release rope speed of the winch's release rope segment, and for adjusting the take-up rope speed of the winch's release rope segment, as well as a release solenoid valve and a take-up solenoid valve. The processor (500) is further configured to: The real-time rope length Lf of the hoist's suspension rope segment at any given time is calculated based on the real-time boom length La, the real-time angle Ra, the real-time rope length L, and the triangular relationship model constructed based on the hoist position, the boom tail hinge point position, and the boom head position. The change in the real-time rope length Lf during boom extension and retraction relative to the time before boom extension and retraction is taken as the local change in the rope length of the hoist's suspension rope segment.

11. The control system for a multi-winch single-hook crane according to claim 9, wherein, The processor (500) is also configured to: When the boom is extending and retracting and the winch is releasing the rope, if it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value, the second winch monitoring assembly is adjusted to stop the change of the total rope length change D4. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, the first winch monitoring assembly is adjusted to stop the change of the total rope length change D3.

12. The control system for a multi-winch single-hook crane according to claim 10, wherein, The processor (500) is also configured to: When the boom is extending and the winch is retracting the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the decreasing rate of the total rope length change D4 greater than the decreasing rate of the total rope length change D3. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to make the decreasing rate of the total rope length change D4 less than the decreasing rate of the total rope length change D3, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

13. The control system for a multi-winch single-hook crane according to claim 12, wherein, The processor (500) is also configured to: When the boom is extending and retracting and the winch is retracting the rope, if it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value, the first winch monitoring assembly is adjusted to stop the change of the total rope length change D3. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, the second winch monitoring assembly is adjusted to stop the change of the total rope length change D4.

14. The control system for a multi-winch single-hook crane according to claim 10, wherein, The processor (500) is also configured to: When the boom is extending or retracting and the winch is not retracting or extending the rope, if it is determined that the rope length compensation deviation D5 is greater than the upper threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to reduce the total rope length change D4 while keeping the total rope length change D3 unchanged. Alternatively, if it is determined that the rope length compensation deviation D5 is less than the lower threshold of the allowable compensation deviation range, the second winch monitoring assembly is adjusted to increase the total rope length change D4 while keeping the total rope length change D3 unchanged, until the rope length compensation deviation D5 is within the allowable compensation deviation range.

15. The control system for a multi-winch single-hook crane according to claim 14, wherein, The processor (500) is also configured to: When the boom is extending or retracting and the winch is not retracting or extending the rope, if it is determined that the rope length compensation deviation D5 is greater than the preset limit compensation positive deviation value or the rope length compensation deviation D5 is less than the preset limit compensation negative deviation value, the boom extension or retraction will be stopped.

16. A multi-winch single-hook crane, comprising a control system for a multi-winch single-hook crane according to any one of claims 9 to 15.

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