A PLC-based overhead traveling crane anti-swing control method

Abstract

The application belongs to the technical field of industrial automation control, and discloses a roof car anti-swing control method based on PLC. m The application divides the roof car running path into three stages of acceleration, uniform speed and deceleration, and adopts a multi-section acceleration and deceleration strategy in each stage. n In the acceleration stage, the path is divided into sections, and after each section, the roof car runs at a uniform speed for a period of time. In the deceleration stage, the path is also divided into sections, and after each section, the roof car runs at a uniform speed for a period of time. The actual maximum speed is adaptively determined by comparing the size relationship between each acceleration section and each deceleration section. The accurate matching of the stroke and the speed is realized through an acceleration and deceleration interval calculation formula. The running safety is ensured by setting the upper and lower limits of the frequency. The application adopts pure open-loop control and does not require additional sensors, which is low in cost and high in reliability, especially suitable for harsh industrial environments such as metallurgy, and can effectively suppress load swing and improve positioning accuracy.

Description

Technical Field

[0001] This application belongs to the field of industrial automation control technology, specifically relating to a PLC-based method for preventing overhead crane swaying. Background Technology

[0002] Overhead cranes, also known as bridge cranes, are widely used in industrial production for lifting heavy objects. Due to the flexibility of the lifting ropes, the load will swing when the crane's trolley or carriage starts, accelerates, decelerates, or stops. This swinging not only affects positioning accuracy but can also lead to safety hazards, such as collisions with equipment or the load falling off. In existing technologies, anti-sway control of overhead cranes mainly adopts the following methods: First, mechanical anti-sway devices: Sway is suppressed by adding mechanical damping structures to the lifting device. However, this method increases mechanical complexity, has high maintenance costs, and limited anti-sway effect. Second, open-loop speed curve control: Sway is reduced to some extent by preset S-shaped or trapezoidal speed curves, but it cannot be dynamically adjusted according to actual load weight, rope length, and other parameters, resulting in poor adaptability. Third, closed-loop feedback control, such as PID and visual feedback: Sway angle is detected by sensors or vision systems for closed-loop control. This method has good anti-sway effect but is complex, costly, and requires extremely high sensor accuracy and reliability, making long-term stable operation difficult in harsh environments such as metallurgy. Fourth, anti-sway control based on input shaping: Sway is suppressed by shaping the speed command input so that the two pulse responses of the drive signal cancel each other out. This method does not require feedback sensors but requires precise knowledge of the system's natural frequency and is sensitive to parameter changes.

[0003] The shortcomings of the existing technology are mainly reflected in: (1) mechanical anti-sway increases the system complexity and maintenance cost; (2) open-loop control mode has poor adaptability and cannot cope with different working conditions; (3) closed-loop feedback mode is complex and costly, and its reliability is difficult to guarantee in harsh industrial environments; (4) most of the existing PLC open-loop control schemes adopt simple trapezoidal speed curves, do not perform fine segmented control of acceleration and deceleration processes, have unsatisfactory anti-sway effect, and do not fully consider the matching relationship between the frequency converter acceleration and deceleration time parameters and the speed segmentation strategy.

[0004] Therefore, there is an urgent need for a low-cost, highly reliable overhead crane anti-sway control algorithm that is suitable for PLC control systems, capable of effectively suppressing load sway under open-loop conditions, while adapting to different operating distances and speed requirements. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, such as unsatisfactory open-loop anti-sway control effect of PLC, insufficient consideration of inverter characteristic parameters in speed curve design, and inability to adapt to different operating distances, this application provides a PLC-based anti-sway control method for overhead cranes. This method divides the operating path into three stages: acceleration, constant speed, and deceleration, and adopts a multi-stage acceleration and deceleration strategy in each stage. It also calculates the speed setpoint by combining the acceleration and deceleration time parameters of the inverter, thereby effectively suppressing load sway under open-loop conditions.

[0006] To achieve the above objectives, this application employs the following technical solution:

[0007] This application discloses a PLC-based method for preventing overhead crane swaying, comprising the following steps:

[0008] Step 1, Data Initialization: Set the number of acceleration segments for the overhead crane. Number of deceleration segments The time of each constant speed operation during the acceleration phase The time of each segment of constant speed operation during the deceleration phase Real-time reading of the crane's coordinates; and All values ​​are positive integers; Step 2: Calculate and determine the actual maximum speed: Compare the equivalent travel of the crane's single acceleration segment with the equivalent travel of its single deceleration segment to determine whether to use acceleration or deceleration to determine the crane's actual maximum speed. ;

[0009] Step 3: Utilize the preset number of acceleration segments for the overhead crane. Number of deceleration segments Based on the actual maximum speed of the crane Reverse calculation of actual acceleration stages and the actual number of deceleration stages Meanwhile, based on the inverter's acceleration time Deceleration time and maximum frequency Calculate the acceleration ramp time Deceleration ramp time and acceleration frequency increment Deceleration frequency increment ;

[0010] Step 4, Speed ​​calculation during the acceleration phase: based on the actual number of acceleration phases determined in Step 3. and accelerating ramp time and acceleration frequency increment Combined with the preset acceleration phase, each segment of constant speed running time Calculate the acceleration frequency setpoint and perform frequency limiting based on the setpoint. This applies to all sub-cycles of the acceleration phase, i.e., the actual number of acceleration segments. After the segment is completed, it automatically enters the constant speed stage of step 5;

[0011] Step 5, during the constant speed phase, the frequency setpoint is maintained at the frequency corresponding to the actual maximum speed, while the remaining distance is determined in real time. When the remaining distance is less than or equal to the total distance required for deceleration Then proceed to step 6, the deceleration phase;

[0012] Step 6, Speed ​​calculation during deceleration phase: based on the actual number of deceleration stages determined in Step 3. and deceleration ramp time and deceleration frequency increment Combined with the preset deceleration constant speed maintenance time Calculate the deceleration frequency setpoint and perform frequency limiting based on the setpoint; the frequency during the deceleration phase starts from... Initially, decrease by one for each completed sub-cycle. Until it drops to 0 Hz, the total number of sub-cycles in the deceleration phase, i.e., the total number of actual deceleration stages. After the segment is completed, it automatically proceeds to step 7 for range positioning and processing;

[0013] Step 7, Positioning Interval Processing: When approaching the target position, the frequency setpoint is set to zero: When |current position - target position| ≤ positioning interval, the frequency setpoint is directly set to zero, the crane stops, and this operation is not limited by the lower frequency limit, i.e., 0 Hz output is allowed.

[0014] A further improvement of this application is that step 2 specifically comprises:

[0015] The crane's acceleration single-segment equivalent stroke for:

[0016]

[0017] The equivalent travel of the overhead crane's deceleration single segment for:

[0018]

[0019] in, This represents the maximum linear velocity of the overhead crane. For the acceleration time of the frequency converter, For the deceleration time of the frequency converter, if If the acceleration is positive, the actual maximum speed is determined by acceleration; otherwise, the actual maximum speed is determined by deceleration.

[0020] A further improvement of this application is that, in step 3, based on the actual maximum speed of the crane... Reverse calculation of actual acceleration stages and the actual number of deceleration stages Specifically, the steps include the following:

[0021] Step 3.1, calculate the first... The section ends with the crane accelerating and accumulating travel distance. and the The cumulative travel distance of the overhead crane at the end of the section. :

[0022]

[0023]

[0024] in, For the first Segment acceleration number of segments and , For the first Number of deceleration segments and ;

[0025] Step 3.2: Based on the equivalent stroke of the crane's single acceleration segment Equivalent travel of single-stage deceleration of the overhead crane By comparing the acceleration and deceleration, we can determine whether the actual maximum speed of the crane is determined by acceleration or deceleration. And based on the actual maximum speed The actual number of acceleration and deceleration stages is calculated by reverse calculation, specifically as follows:

[0026] when At that time, the actual maximum speed is determined by acceleration. :

[0027]

[0028] in, The actual number of acceleration stages obtained through reverse calculation. Find the smallest Make > ,but ,in, The actual total running distance that can be used for acceleration and deceleration Half of the speed increase per segment = Find the smallest integer satisfy ,but ;like ,but ;

[0029] when At that time, the actual maximum speed is determined by deceleration. :

[0030]

[0031] in, The actual number of deceleration stages is obtained through reverse calculation, and the speed increment ∆ for each deceleration stage is... = Find the smallest integer satisfy ,but .

[0032] A further improvement of this application is that, in step 3, the frequency increment is accelerated. Deceleration frequency increment This refers to each step increment of the inverter's output frequency, that is, the amount of frequency change corresponding to the segmented change in speed when the inverter drives the motor:

[0033]

[0034]

[0035] Accelerate ramp time for:

[0036]

[0037] deceleration ramp time for:

[0038]

[0039] Accelerate ramp time and deceleration ramp time It is the ramp time required for the inverter to change the frequency, and the constant speed time during the acceleration phase. Constant speed time during deceleration phase Together they form an acceleration / deceleration sub-cycle.

[0040] A further improvement in this application is that step 4 specifically includes the following steps:

[0041] Step 4.1: Set up an acceleration timer Starting from 0, the duration of each acceleration sub-cycle is...

[0042]

[0043] Current acceleration segment number Starting from 1:

[0044] ;

[0045] Step 4.2: Calculate the acceleration frequency setpoint. And frequency limiting:

[0046]

[0047] when At that time, the frequency remained at It enters the uniform speed stage.

[0048] A further improvement of this application is that, in step 5, during the constant speed phase, the remaining distance is calculated in real time. for:

[0049] ;

[0050] Total distance required for deceleration for:

[0051]

[0052] in, To complete all deceleration stages Cumulative travel due to deceleration The target location coordinates for this operation are: The coordinates of the crane's current position are obtained in real time via the encoder. This is the distance to the positioning interval. When the distance to the target is less than this value, the frequency will be set to zero and the system will stop. The unit is mm. The extra buffer distance is reserved to ensure safety during deceleration trigger calculations; the unit is mm.

[0053] The remaining distance Total distance required for deceleration In comparison, The deceleration phase is triggered at that time.

[0054] A further improvement in this application is that step 6 specifically includes the following steps:

[0055] Step 6.1: After entering the deceleration phase, the deceleration timer... Starting from 0, the duration of each deceleration sub-cycle Current deceleration segment number Starting from 1:

[0056]

[0057] Step 6.2, from Start by reducing one segment at a time. Calculate the given deceleration frequency:

[0058]

[0059] Step 6.3: Based on the deceleration frequency setpoint Frequency limiting:

[0060]

[0061] when At that time, the frequency drops to 0 Hz, after which it enters the positioning interval processing.

[0062] The beneficial effects of this application are:

[0063] This application adopts pure open-loop control, which does not require additional sensors or vision systems, resulting in low cost and high reliability, making it particularly suitable for harsh industrial environments such as metallurgy.

[0064] This application divides the acceleration and deceleration process into multiple segments and inserts a constant speed running time between each segment, making the speed change smoother and effectively suppressing load sway.

[0065] This application fully considers the matching relationship between the inverter's acceleration and deceleration time parameters and the speed segmentation strategy, so that the anti-sway effect is adapted to the equipment characteristics.

[0066] This application can adaptively adjust the actual maximum speed and the actual number of acceleration and deceleration stages according to the actual running distance to adapt to different working conditions.

[0067] The calculation method for acceleration and deceleration intervals in this application is highly innovative and can achieve precise matching of travel and speed. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of the overall process of this application;

[0069] Figure 2 This is a schematic diagram of the crane's operating speed curve, which includes three stages: acceleration, constant speed, and deceleration, as described in this application.

[0070] Figure 3 This is a flowchart of the segmented speed control logic for the acceleration phase of this application.

[0071] Figure 4 This is a flowchart of the segmented speed control logic during the deceleration phase of this application.

[0072] Figure 5 This is the flowchart of the logic for determining the actual maximum speed in this application.

[0073] Figure 6 This is a block diagram of the overhead crane control system using this application. Detailed Implementation

[0074] The embodiments of this application will be disclosed below with reference to the drawings. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details should not be used to limit this application. That is, in some embodiments of this application, these practical details are not necessary. In addition, for the sake of simplicity, some conventional structures and components will be shown in the drawings in a simple schematic manner.

[0075] In this embodiment, the crane anti-sway control algorithm is implemented in a Siemens S7-1500 series PLC (Programmable Logic Controller), and the inverter's acceleration time... The deceleration time of the frequency converter Both are 2.0s, the maximum linear velocity on the crane nameplate. Accelerate the number of segments Number of deceleration segments The time of each constant speed operation during the acceleration phase The time of each uniform speed operation during the deceleration phase Maximum frequency Minimum operating frequency The positioning interval is set to 50mm, and the buffer interval is set to 100mm.

[0076] like Figure 2 The diagram shows the overhead crane's operating speed curves, which include acceleration, constant speed, and deceleration phases. Figure 2 The zigzag line presents a stepped shape of "upward → horizontal → upward → horizontal" because a period of constant speed operation (dashed horizontal segment) is inserted after each acceleration segment. The purpose of the constant speed maintenance segment is to allow the swaying of the wire rope to naturally decay under constant speed conditions, which is the core design for achieving the anti-sway effect. Each segment of "sloping upward (solid line) + constant speed maintenance (dashed line)" constitutes an acceleration sub-cycle, and the total duration of the cycle is... .

[0077] like Figure 1 , Figure 6 As shown, this application discloses a PLC-based anti-sway control method for overhead cranes, comprising the following steps:

[0078] Step 1, Data Initialization: Set the number of acceleration segments for the overhead crane. Number of deceleration segments The acceleration phase and the time of each segment of constant speed operation The time of each uniform speed operation during the deceleration phase Read the current coordinate position fed back by the encoder in real time; initialize the output frequency to 0Hz;

[0079] Step 2: Calculate and determine the actual maximum speed: Compare the equivalent travel of the crane's single acceleration segment with the equivalent travel of its single deceleration segment to determine whether to use acceleration or deceleration to determine the crane's actual maximum speed. .like Figure 5 As shown, if the starting coordinate is 0mm and the target coordinate is 5000mm, then the total distance is 5000mm. After deducting the positioning interval of 50mm and the buffer interval of 100mm, the distance that can be used for acceleration and deceleration is 4850mm, half of which is 2425mm.

[0080] Step 2 is as follows:

[0081] The crane's acceleration single-segment equivalent stroke for:

[0082]

[0083] The equivalent travel of the overhead crane's deceleration single segment for:

[0084]

[0085] in, This represents the maximum linear velocity of the overhead crane. For the acceleration time of the frequency converter, For the deceleration time of the frequency converter, if If the acceleration is positive, the actual maximum speed is determined by acceleration; otherwise, the actual maximum speed is determined by deceleration.

[0086] Step 3: Utilize the preset number of acceleration segments for the overhead crane. Number of deceleration segments Perform reverse calculation of the number of segments under the overhead crane travel constraint, based on the actual maximum speed of the overhead crane. Reverse calculation of actual acceleration stages and the actual number of deceleration stages Meanwhile, based on the inverter's acceleration time Deceleration time and maximum frequency Calculate the acceleration ramp time Deceleration ramp time and acceleration frequency increment Deceleration frequency increment ;

[0087] In step 3, based on the actual maximum speed of the crane... Reverse calculation of actual acceleration stages and the actual number of deceleration stages Specifically, it includes the following steps:

[0088] Step 3.1, calculate the first... The section ends with the crane accelerating and accumulating travel distance. and the The cumulative travel distance of the overhead crane at the end of the section. :

[0089]

[0090]

[0091] in, For the first Segment acceleration number of segments and , For the first Number of deceleration segments and ;

[0092] Step 3.2: Based on the equivalent stroke of the crane's single acceleration segment Equivalent travel of single-stage deceleration of the overhead crane By comparing the acceleration and deceleration, we can determine whether the actual maximum speed of the crane is determined by acceleration or deceleration. And based on the actual maximum speed The actual number of acceleration and deceleration stages is calculated by reverse calculation, specifically as follows:

[0093] when At that time, the actual maximum speed is determined by acceleration. :

[0094]

[0095] in, The actual number of acceleration stages obtained through reverse calculation. Find the smallest Make > ,but ,in, The actual total running distance that can be used for acceleration and deceleration Half of the speed increase per segment = Find the smallest integer satisfy ,but ;like ,but ;

[0096] when At that time, the actual maximum speed is determined by deceleration. :

[0097]

[0098] in, The actual number of deceleration stages is obtained through reverse calculation, and the speed increment ∆ for each deceleration stage is... = Find the smallest integer satisfy ,but .

[0099] for Loop calculation:

[0100] when When S1 = (2*1*2000*1.0) / (2*5) + (1*2.0*2000) / (2*5) = 400 + 400 = 800 mm < 2425 mm, continue the cycle;

[0101] when When S2 = (3*2*2000*1.0) / (2*5) + (2*2.0*2000) / (2*5) = 1200 + 800 = 2000 mm < 2425 mm, continue the cycle;

[0102] when hour, S3 = (4*3*2000*1.0) / (2*5) + (3*2.0*2000) / (2*5) = 2400 + 1200 = 3600mm > 2425 mm, stop the cycle;

[0103] Therefore, when When the cumulative deceleration distance first exceeds half of the total distance, the actual number of deceleration stages is [number missing]. Actual maximum speed .

[0104] Then, by cyclically calculating the number of acceleration segments, the actual number of acceleration segments is determined: find the one that makes... The critical point.

[0105] when hour, Therefore, the actual number of acceleration stages .

[0106] In step 3, based on the inverter's acceleration time Deceleration time and maximum frequency Calculate the acceleration ramp time Deceleration ramp time and acceleration frequency increment Deceleration frequency increment Specifically:

[0107] Acceleration frequency increment Deceleration frequency increment This refers to each step increment of the inverter's output frequency, that is, the frequency change corresponding to the segmented change in speed when the inverter drives the motor:

[0108]

[0109]

[0110] Accelerate ramp time for:

[0111]

[0112] deceleration ramp time for:

[0113]

[0114] Accelerate ramp time and deceleration ramp time It is the ramp time required for the inverter to change the frequency, and the constant speed time during the acceleration phase. Constant speed time during deceleration phase Together they form an acceleration / deceleration sub-cycle.

[0115] Step 4, Speed ​​calculation during the acceleration phase: based on the actual number of acceleration phases determined in Step 3. and accelerating ramp time and acceleration frequency increment Combined with the preset acceleration phase, each segment of constant speed running time Calculate the acceleration frequency setpoint and perform frequency limiting based on the setpoint. This applies to all sub-cycles of the acceleration phase, i.e., the actual number of acceleration segments. After the segment is completed, it automatically enters the constant speed stage of step 5;

[0116] like Figure 3 As shown, step 4 specifically includes the following steps:

[0117] Step 4.1: Set up an acceleration timer Starting from 0, the duration of each acceleration sub-cycle is...

[0118]

[0119] Current acceleration segment number Starting from 1:

[0120] ;

[0121] Step 4.2: Calculate the acceleration frequency setpoint. And frequency limiting:

[0122]

[0123] when At that time, the frequency remained at It enters the uniform speed stage.

[0124] In this embodiment, =2, =0.6s, =0.4s, therefore =1.0s.

[0125] when hour, =1, =1×10=10Hz;

[0126] When 1.0s At 2.0s, =2, =2×10=20Hz

[0127] when hour, Maintain a value of 2, keep the frequency at 20Hz, and the acceleration phase ends.

[0128] Limiting check: 20Hz Within the specified range, no adjustments are needed.

[0129] Step 5, during the constant speed phase, the frequency setpoint is maintained at 20Hz, the frequency corresponding to the actual maximum speed, while the remaining distance is determined in real time. When the remaining distance is less than or equal to the total distance required for deceleration Then proceed to step 6, the deceleration phase, which specifically involves calculating the remaining distance in real time during the constant speed phase. for:

[0130] ;

[0131] Total distance required for deceleration for:

[0132]

[0133] in, To complete all deceleration stages Cumulative travel due to deceleration The target location coordinates for this operation are: The coordinates of the crane's current position are obtained in real time via the encoder. This is the distance to the positioning interval. When the distance to the target is less than this value, the frequency will be set to zero and the system will stop. The unit is mm. An additional buffer distance, in mm, is reserved to ensure safety during deceleration trigger calculations; the remaining distance... Total distance required for deceleration In comparison, The deceleration phase is triggered at a certain time. In this embodiment, =2, =50mm, =100mm, therefore =2150mm. During the constant speed process, when the remaining distance is less than or equal to 2150mm, the speed will decrease.

[0134] Step 6, Speed ​​calculation during deceleration phase: based on the actual number of deceleration stages determined in Step 3. and deceleration ramp time and deceleration frequency increment Combined with the preset deceleration constant speed maintenance time Calculate the deceleration frequency setpoint and perform frequency limiting based on the setpoint; the frequency during the deceleration phase starts from... Initially, decrease by one for each completed sub-cycle. Until it drops to 0 Hz, the total number of sub-cycles in the deceleration phase, i.e., the total number of actual deceleration stages. After the segment is completed, it automatically proceeds to step 7 for locating the interval for processing.

[0135] like Figure 4 As shown, step 6 specifically includes the following steps:

[0136] Step 6.1: After entering the deceleration phase, the deceleration timer... Starting from 0, the duration of each deceleration sub-cycle Current deceleration segment number Starting from 1:

[0137]

[0138] Step 6.2, from Start by reducing one segment at a time. Calculate the given deceleration frequency:

[0139]

[0140] Step 6.3: Based on the deceleration frequency setpoint Frequency limiting:

[0141]

[0142] when At that time, the frequency drops to 0 Hz, after which it enters the positioning interval processing.

[0143] In this embodiment:

[0144] =2, =1.0s, =0.4s, therefore .

[0145] when hour, =1, .

[0146] when hour, =2, .

[0147] when At this time, the frequency remains at 0Hz, waiting to enter the positioning range. VII. Positioning Range Processing

[0148] when When the distance is 50mm, the final frequency is set to 0, the crane stops, and the positioning is completed. The current position coordinates of the overhead crane are obtained in real time through the encoder, in mm. These are the target location coordinates for this operation, in mm. This is the distance to the positioning interval. When the distance to the target is less than this value, the frequency will be set to zero and the system will stop. The unit is mm.

[0149] To verify the adaptive capability of this application, tests were conducted at different operating distances:

[0150] (1) Short-distance operation (total distance 500mm): At this time, the acceleration and deceleration capabilities are not limited. The actual maximum speed is determined by the total distance. The actual number of acceleration stages and the actual number of deceleration stages are both less than the set value. The crane runs smoothly at a low speed and has a good anti-sway effect.

[0151] (2) Medium-distance operation (total distance 5000mm): As described in the previous steps, this application adaptively determines the actual maximum speed and the actual number of acceleration and deceleration stages;

[0152] (3) Long-distance operation (total distance 20000mm): At this time, the total distance is large enough, and the actual number of acceleration stages = the set number of acceleration stages. =5, Actual number of deceleration stages = Set number of deceleration stages =5, actual maximum speed= =2000mm / s, the crane experiences a complete acceleration-uniform speed-deceleration process.

[0153] Test results show that this application can adaptively adjust the speed curve according to different running distances, achieve good anti-sway effect under various working conditions, with a maximum load swing angle of less than 2 degrees and a positioning accuracy better than ±50mm.

[0154] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A PLC-based method for preventing overhead crane swaying, characterized in that: The overhead crane anti-sway control method includes the following steps: Step 1, Data Initialization: Set the number of acceleration segments for the overhead crane. Number of deceleration segments The time of each constant speed operation during the acceleration phase The time of each segment of constant speed operation during the deceleration phase Real-time reading of the crane's coordinates; and All values ​​are positive integers; Step 2: Calculate and determine the actual maximum speed: Compare the equivalent travel of the crane's single acceleration segment with the equivalent travel of its single deceleration segment to determine whether to use acceleration or deceleration to determine the crane's actual maximum speed. ; Step 3: Utilize the preset number of acceleration segments for the overhead crane. Number of deceleration segments Based on the actual maximum speed of the crane Reverse calculation of actual acceleration stages and the actual number of deceleration stages ; At the same time, according to the acceleration time of the frequency converter Deceleration time and maximum frequency Calculate the acceleration ramp time Deceleration ramp time and acceleration frequency increment Deceleration frequency increment ; Step 4, Speed ​​calculation during the acceleration phase: based on the actual number of acceleration phases determined in Step 3. and accelerating ramp time and acceleration frequency increment Combined with the preset acceleration phase, each segment of constant speed running time Calculate the acceleration frequency setpoint and perform frequency limiting based on the setpoint. This applies to all sub-cycles of the acceleration phase, i.e., the actual number of acceleration segments. After the segment is completed, it automatically enters the constant speed stage of step 5; Step 5, during the constant speed phase, the frequency setpoint is maintained at the frequency corresponding to the actual maximum speed, while the remaining distance is determined in real time. When the remaining distance is less than or equal to the total distance required for deceleration, proceed to step 6, the deceleration stage. Step 6, Speed ​​calculation during deceleration phase: based on the actual number of deceleration stages determined in Step 3. and deceleration ramp time and deceleration frequency increment Combined with the preset deceleration constant speed maintenance time Calculate the deceleration frequency setpoint and perform frequency limiting based on the setpoint; the frequency during the deceleration phase starts from... Initially, decrease by one for each completed sub-cycle. Until it drops to 0 Hz, the total number of sub-cycles in the deceleration phase, i.e., the total number of actual deceleration stages. After the segment is completed, it automatically proceeds to step 7 for range positioning and processing; Step 7, Positioning Interval Processing: When approaching the target position, the frequency setpoint is set to zero: When |current position - target position| ≤ the positioning interval, the frequency setpoint is directly set to zero, the crane stops, and this operation is not limited by the lower frequency limit, i.e., 0Hz output is allowed.

2. The PLC-based anti-sway control method for overhead cranes according to claim 1, characterized in that: Step 2 specifically involves: The crane's acceleration single-segment equivalent stroke for: The equivalent travel of the overhead crane's deceleration single segment for: in, This represents the maximum linear velocity of the overhead crane. For the acceleration time of the frequency converter, For the deceleration time of the frequency converter, if If the acceleration is positive, the actual maximum speed is determined by acceleration; otherwise, the actual maximum speed is determined by deceleration.

3. The PLC-based anti-sway control method for overhead cranes according to claim 2, characterized in that: In step 3, based on the actual maximum speed of the crane... Reverse calculation of actual acceleration stages and the actual number of deceleration stages Specifically, the steps include the following: Step 3.1, calculate the first... The section ends with the crane accelerating and accumulating travel distance. and the The cumulative travel distance of the overhead crane at the end of the section. : in, For the first Segment acceleration number of segments and , For the first Number of deceleration segments and ; Step 3.2: Based on the equivalent stroke of the crane's single acceleration segment Equivalent travel of single-stage deceleration of the overhead crane By comparing the acceleration and deceleration, we can determine whether the actual maximum speed of the crane is determined by acceleration or deceleration. And based on the actual maximum speed The actual number of acceleration and deceleration stages is calculated by reverse calculation, specifically as follows: when At that time, the actual maximum speed is determined by acceleration. : in, The actual number of acceleration stages obtained through reverse calculation. Find the smallest Make > ,but ,in, The actual total running distance that can be used for acceleration and deceleration Half of the speed increase per segment = Find the smallest integer satisfy ,but ;like ,but ; when At that time, the actual maximum speed is determined by deceleration. : in, The actual number of deceleration stages is obtained through reverse calculation, and the speed increment ∆ for each deceleration stage is... = Find the smallest integer satisfy ,but .

4. The PLC-based anti-sway control method for overhead cranes according to claim 1, characterized in that: In step 3, the frequency increment is accelerated. Deceleration frequency increment This refers to each step increment of the inverter's output frequency, that is, the amount of frequency change corresponding to the segmented change in speed when the inverter drives the motor: Accelerate ramp time for: deceleration ramp time for: Accelerate ramp time and deceleration ramp time It is the ramp time required for the inverter to change the frequency, and the constant speed time during the acceleration phase. Constant speed time during deceleration phase Together they form an acceleration / deceleration sub-cycle.

5. The PLC-based anti-sway control method for overhead cranes according to claim 4, characterized in that: Step 4 specifically includes the following steps: Step 4.1: Set up an acceleration timer Starting from 0, the duration of each accelerated sub-cycle is: Current acceleration segment number Starting from 1: ; Step 4.2: Calculate the acceleration frequency setpoint. And frequency limiting: when At that time, the frequency remained at It enters the uniform speed stage.

6. The PLC-based anti-sway control method for overhead cranes according to claim 5, characterized in that: In step 5, during the constant speed phase, the remaining distance is calculated in real time. for: ； Total distance required for deceleration for: in, To complete all deceleration stages Cumulative travel due to deceleration The target location coordinates for this operation are: The coordinates of the crane's current position are obtained in real time via the encoder. To locate the distance between intervals, Additional buffer distance is reserved. The remaining distance Total distance required for deceleration In comparison, The deceleration phase is triggered at that time.

7. The PLC-based anti-sway control method for overhead cranes according to claim 6, characterized in that: Step 6 specifically includes the following steps: Step 6.1: After entering the deceleration phase, the deceleration timer... Starting from 0, the duration of each deceleration sub-cycle Current deceleration segment number Starting from 1: Step 6.2, from Start by reducing one segment at a time. Calculate the given deceleration frequency: Step 6.3: Based on the deceleration frequency setpoint Frequency limiting: when At that time, the frequency drops to 0 Hz, after which it enters the positioning interval processing.

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