Dual-crane multi-axis synchronous control method and system based on laser communication

Abstract

The application discloses a double-crane multi-axis synchronous control method and system based on laser communication and relates to the technical fields of crane motion control and laser communication. The double-crane multi-axis synchronous control method based on laser communication comprises the following steps: S1, constructing a double-machine synchronous source state data set; S2, analyzing the delay change trend in the communication period based on the double-machine synchronous source state data set; S3, introducing a link stable state and a control period boundary relationship, and performing synchronous instruction arrival time sequence discrimination; and S4, performing master-slave crane multi-axis operation consistency evaluation according to an effective alignment state. The problems that the communication time delay and period of the laser communication link are dithered under the action of structural vibration, optical machine micro-deviation and air flow disturbance, and the arrival time of the control instruction and the control period boundary are misaligned are solved.

Description

Technical Field

[0001] This invention relates to the fields of crane motion control and laser communication technology, specifically to a method and system for synchronous control of multiple axes of dual cranes based on laser communication. Background Technology

[0002] With the increasing demands for precision in the collaborative lifting of heavy objects in large-scale equipment manufacturing, port logistics, and high-end handling scenarios, multi-axis synchronous control of dual cranes is gradually becoming a key technology. Crane motion control relies on servo drives and multi-axis collaborative scheduling to achieve precise matching of position and speed. The development of wireless communication technology has provided a non-contact transmission means for data interaction between master and slave control systems. Among them, laser communication, with its high bandwidth, low latency, and anti-electromagnetic interference capabilities, is gradually being applied in the field of industrial control to support high real-time control command transmission and status feedback.

[0003] For example, the invention patent with announcement number CN120172271B discloses a synchronous control method for dual winches of a crane, including: real-time acquisition of the operating condition data of the dual winches of the crane, calculation of the speed synchronization error and displacement error of the dual winches of the crane, inputting the operating condition data of the dual winches of the crane into a pre-trained decision tree operating condition classification model, outputting the operating condition type, and calling the corresponding synchronous control model based on the operating condition category and an LSTM neural network model trained for multiple operating conditions; based on the monitored synchronous speed error and synchronous displacement error, if the synchronous speed error and synchronous displacement error are less than the expected control accuracy, further fine-tuning the control parameters, and re-examining the accuracy of the decision tree operating condition classification model and the LSTM neural network synchronous control model to optimize and improve the model.

[0004] For example, the invention patent with announcement number CN115884938B discloses a crane with a synchronous adjustment function for winding and lifting, which synchronizes the load sharing of each hook when using three or more hooks for joint lifting. Regarding the speed control of the winding and lifting motors of multiple hooks, the speed is controlled separately so that during winding and lifting, the speed decreases as the motor load increases and increases as the motor load decreases; and during winding and falling, the speed increases as the motor load increases and decreases as the motor load decreases. Thus, by operating in the following manner: during winding and lifting, the hook with a larger load sharing than other hooks has a slower speed compared to the other hooks, and the hook with a smaller load sharing than other hooks has a faster speed compared to the other hooks; and during winding and falling, the hook with a larger load sharing than other hooks has a faster speed compared to the other hooks, and the hook with a smaller load sharing than other hooks has a slower speed compared to the other hooks. Therefore, during the joint lifting of multiple hooks, the load is shared among the hooks.

[0005] Existing dual-crane synchronous control systems mostly employ wired bus communication or conventional wireless communication, achieving coordinated operation through periodic exchange of speed curves and position information between master and slave controllers. Some solutions combine fixed delay compensation or simple error feedback mechanisms to maintain synchronization. However, in actual operation, communication link delays fluctuate, and the arrival time of control commands can easily deviate from the control cycle boundary. Furthermore, the overlapping of changes in the operating states of multiple axes makes it difficult to stably control synchronization errors, affecting the consistency of overall coordinated operation.

[0006] To address the above issues, there is an urgent need for a method and system for multi-axis synchronous control of dual cranes based on laser communication. Summary of the Invention

[0007] Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a method and system for multi-axis synchronous control of dual cranes based on laser communication. This method solves the problem that the communication delay and cycle of the laser communication link fluctuate under the influence of structural vibration, optomechanical micro-bias, and airflow disturbance, causing the arrival time of control commands to be misaligned with the boundary of the control cycle.

[0008] Technical solution To achieve the above objectives, the present invention provides the following technical solution: a dual-crane multi-axis synchronous control method based on laser communication, comprising the following steps: S1, collecting basic data of dual-crane synchronous control directly generated during the multi-axis synchronous operation of the dual cranes, constructing a dual-crane synchronous source state dataset, and preprocessing the dual-crane synchronous source state dataset; S2, analyzing the delay change trend within the communication cycle based on the dual-crane synchronous source state dataset, determining the stability of the laser communication link, and outputting the link stability state; S3, introducing the link stability state and the boundary relationship of the control cycle, performing synchronization command arrival timing discrimination, and determining the effective alignment state of the synchronization control command in the control cycle; S4, performing a master-slave crane multi-axis operation consistency evaluation based on the effective alignment state, and outputting the synchronous adjustment control of the slave servo drive.

[0009] Furthermore, the specific steps for collecting the basic data of dual-machine synchronous control directly generated during the synchronous operation of the dual cranes and constructing the dual-machine synchronous source state dataset are as follows: Collect the basic data of dual-machine synchronous control directly generated during the synchronous operation of the dual cranes and multi-axis, including the master system clock time, slave system clock time, master synchronization command sending trigger signal, slave communication receiving interruption trigger signal, laser wireless communication data frame, communication status word, pulse count of each motion axis encoder of the master, pulse count of each motion axis encoder of the slave, encoder sampling time interval, and control cycle counter count value; all data are accompanied by corresponding control cycle sequence number and system clock identifier; establish a unified time series based on the master system clock time and execute the sequential arrangement; establish a control cycle sequence number index and a communication cycle sequence number index; perform association binding on the laser wireless communication data frame and the communication status word to construct the dual-machine synchronous source state dataset.

[0010] Furthermore, the specific steps for preprocessing the dual-machine synchronous source dataset are as follows: Based on the dual-machine synchronous source dataset, a dual-time reference mapping relationship is constructed between the control cycle index and the communication cycle index; a dynamic time warping algorithm is used to perform periodic-level alignment processing on the control link and the communication link; focusing on the communication link delay fluctuation characteristics, the median absolute deviation method and the local outlier factor algorithm are used to identify and remove abnormal time series points; unified periodic resampling processing is performed on the multi-source time series based on the control cycle counter count value; the range standardization method is used to perform standardization processing on the dual-machine synchronous source dataset; and the max-min normalization method is used to perform normalization processing on the dual-machine synchronous source dataset.

[0011] Further, the specific steps for analyzing the delay variation trend within the communication cycle based on the dual-machine synchronous source state dataset are as follows: Read the host system clock time corresponding to the host synchronization command sending trigger signal, the slave system clock time corresponding to the slave communication reception interrupt trigger signal, and the control cycle counter count value to obtain the host sending time, slave receiving time, preceding sending time, and preceding receiving time; parse the communication status word corresponding to the communication cycle sequence number index and extract the round-trip propagation time field; convert the round-trip propagation time field according to the one-way propagation delay to obtain the link delay time; filter the link delay time... Non-zero values ​​in the historical sequence are sorted numerically, and the smallest positive value is selected for fixed processing to obtain the normalized stability compensation amount, which is then saved to the parameter area. The current period time difference is obtained by subtracting the master transmission time from the slave reception time. The previous period time difference is obtained by subtracting the previous transmission time from the previous reception time. The change in time difference is obtained by subtracting the previous period time difference from the current period time difference. The absolute value of the change in time difference is taken to obtain the change amplitude. The link delay time is added to the normalized stability compensation amount to obtain the normalization reference. The change amplitude is divided by the normalization reference to obtain the link stability metric.

[0012] Further, the specific steps for determining the stability of the laser communication link and outputting the link stability status are as follows: The link stability metric is compared with the link fluctuation threshold in real time; when the link stability metric is less than the link fluctuation threshold, the current cycle transmission time, reception time, and link delay time are written into the time base register, keeping the link delay compensation amount unchanged, maintaining the synchronization command transmission rhythm of the master PLC to the slave PLC unchanged, maintaining the control cycle boundary alignment reference unchanged, and writing the link stability metric into the link status buffer; when the link stability metric is greater than or equal to the link fluctuation threshold, the link delay compensation amount in the time base register is rewritten according to the current cycle link delay time, the synchronization command activation advance is adjusted to the extended value corresponding to the link delay compensation amount, the cycle boundary capture width of the slave PLC's reception result of the synchronization command is extended, and the synchronization speed curve switching time issued by the master PLC in the current cycle is locked.

[0013] Furthermore, the specific steps for introducing the link stability state and control cycle boundary relationship, and executing the synchronization command arrival timing judgment are as follows: Read the count transition position corresponding to the control cycle counter value and match it with the host system clock time to complete the cycle start point time calibration, obtaining the control cycle boundary time; extract the link stability metric value from the link state buffer; call the normalized stability compensation amount based on the parameter area; obtain the slave receiving time and link delay time; subtract the slave receiving time from the control cycle boundary time to obtain the time difference; add the link delay time and the normalized stability compensation amount as the denominator, and perform ratio calculation on the time difference to obtain the time difference ratio; negative the link stability metric value and perform exponential operation to obtain the attenuation term; multiply the time difference ratio by the attenuation term to obtain the command alignment judgment value.

[0014] Further, the specific steps for determining the effective alignment status of the synchronization control command in the control cycle are as follows: The command alignment determination value is compared with the alignment threshold in real time, the alignment threshold including a first-level alignment threshold and a second-level alignment threshold; when the command alignment determination value is less than the first-level alignment threshold, the dequeue action of the current cycle synchronization command in the command buffer is frozen, the slave servo driver maintains the execution of the speed curve of the previous control cycle, the current synchronization command is written into the pre-loading area of ​​the next cycle, and the effective time of the current control cycle is reset; when the command alignment determination value is greater than or equal to the first-level alignment threshold and less than the second-level alignment threshold, the current synchronization command is written into the cycle-end buffer, the synchronization command is loaded at a fixed sampling point before the end of the current control cycle, and the effective time of the synchronization command is rewritten to the end-alignment time of this cycle, while the acquisition cycle of master and slave axis displacement, position, and speed is switched to a dense refresh sampling cycle; when the command alignment determination value is greater than or equal to the second-level alignment threshold, the dequeue restriction of the synchronization command in the command buffer is released, the synchronization speed curve segment is written into the slave trajectory register area, and loaded into the reference input terminal of the slave servo driver according to the boundary time of the current control cycle, while the command alignment determination value is written into the effective status area.

[0015] Further, the specific steps for performing the master-slave crane multi-axis operation consistency assessment based on the effective alignment state are as follows: Read the encoder pulse counts of each motion axis of the master crane, the encoder pulse counts of each motion axis of the slave crane, and the encoder sampling time interval; perform displacement conversion to obtain the current position of the master axis and the current position of the slave axis; calculate the difference in encoder pulse counts of each motion axis of the master crane within two adjacent sampling periods and perform differential conversion in combination with the encoder sampling time interval to obtain the running speed of the master axis; calculate the difference in encoder pulse counts of each motion axis of the slave crane within two adjacent sampling periods and perform differential conversion in combination with the encoder sampling time interval. Perform differential conversion to obtain the slave axis running speed; extract the instruction alignment judgment value from the effective status area; call the normalized stability compensation amount based on the parameter area; subtract the slave axis current position from the master axis current position to obtain the position difference; subtract the slave axis running speed from the master axis running speed to obtain the speed difference; perform a square operation on the speed difference and add it to the normalized stability compensation amount to obtain the square root inner term; perform a square root operation on the square root inner term to obtain the normalized denominator; divide the position difference by the normalized denominator to obtain the position-speed ratio; multiply the position-speed ratio by the instruction alignment judgment value to obtain the synchronization adjustment drive value.

[0016] Further, the specific steps of the synchronous adjustment control of the output slave servo drive are as follows: The synchronous adjustment drive value is called as the synchronous compensation input of the slave servo driver; the synchronous adjustment drive value is converted into a speed correction component of the corresponding motion axis of the slave and superimposed on the current speed curve output value; when the synchronous adjustment drive value is greater than zero, the output speed of the corresponding motion axis of the slave is increased and the current position following error correction cycle is compressed; when the synchronous adjustment drive value is less than zero, the output speed of the corresponding motion axis of the slave is decreased and the current position compensation step size is released; after the speed correction component is written to the driver's given terminal, the slave displacement reference value is compensated in the same direction according to the current position feedback; after completing one compensation output, the displacement, position, and speed of each axis of the master and slave are sampled back, the position difference is recalculated, and the output speed and displacement reference value of the slave servo driver are continuously rewritten according to the updated synchronous adjustment drive value until the position difference is less than or equal to the error threshold, at which point the speed correction component and displacement compensation component are cancelled.

[0017] The second aspect of this invention provides a dual-crane multi-axis synchronous control system based on laser communication, comprising: a source state acquisition module for acquiring basic data of dual-crane synchronous control directly generated during the multi-axis synchronous operation of the dual cranes, constructing a dual-crane synchronous source state dataset, and preprocessing the dual-crane synchronous source state dataset; a link stability identification module for analyzing the delay change trend within the communication cycle based on the dual-crane synchronous source state dataset, determining the stability of the laser communication link, and outputting the link stability state; a command activation alignment module for introducing the link stability state and the boundary relationship of the control cycle, performing synchronization command arrival timing discrimination, and determining the activation alignment state of the synchronization control command in the control cycle; and a multi-axis synchronous adjustment module for performing a master-slave crane multi-axis operation consistency assessment based on the activation alignment state, and outputting synchronous adjustment control of the slave servo drive.

[0018] Beneficial effects The present invention has the following beneficial effects: (1) This invention constructs a dual-machine synchronous source state dataset and establishes a unified time base for the control cycle number index and the communication cycle number index, so that the host sending time and the slave receiving time can be aligned and expressed in the same time system. On this basis, the link delay time and the change in time difference are extracted to form the link stability metric value, so that the delay change within the communication cycle can be continuously characterized and participate in the control decision. Compared with relying only on the fixed delay alignment method, the link state expression is more complete and has continuity during the cycle.

[0019] (2) This invention compares the link stability metric with the link fluctuation threshold in a hierarchical manner and dynamically rewrites the link delay compensation amount. At the same time, it adjusts the synchronization command effective advance amount and the period boundary capture width in combination with the control period boundary relationship, so that the synchronization command has differentiated time base constraints under different link fluctuation states. Compared with the fixed compensation strategy, the synchronization command effective time can be adaptively adjusted with the change of communication state, reducing the accumulation of period misalignment.

[0020] (3) By constructing an instruction alignment judgment value and setting a first-level alignment threshold and a second-level alignment threshold, the present invention performs hierarchical control on the effective alignment status of the synchronization instruction in the control cycle, so that the synchronization instruction switches between freezing, loading at the end of the cycle and loading at the boundary, and adjusts the sampling rhythm synchronously to keep the instruction loading position consistent with the boundary of the control cycle. Compared with the direct execution of instructions, the instruction effective process has clear timing constraints and buffer adjustment capabilities.

[0021] (4) This invention constructs a position-speed ratio based on the current position of the master axis, the current position of the slave axis, the running speed of the master axis, and the running speed of the slave axis, and introduces a command alignment judgment value to form a synchronous adjustment drive value. It continuously rewrites the output speed and displacement reference value of the slave servo driver, and performs continuous compensation under the position difference closed-loop constraint. This allows the multi-axis running consistency evaluation result to be directly converted into drive adjustment input. Compared with a single error correction method, the adjustment process has the characteristics of position and speed synergy, which improves the stability and continuity of the synchronous control process.

[0022] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0023] Figure 1 This is a flowchart of the multi-axis synchronous control method for dual cranes based on laser communication according to the present invention; Figure 2 This is a structural diagram of the dual-crane multi-axis synchronous control system based on laser communication of the present invention; Figure 3 This is a distribution diagram of the synchronous adjustment drive value of the present invention; Figure 4 This is a phase space trajectory diagram of the link delay fluctuation of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see Figures 1-4 This invention provides a technical solution: a multi-axis synchronous control method for dual cranes based on laser communication, comprising the following steps: S1, collecting basic data of dual-machine synchronous control directly generated during the multi-axis synchronous operation of the dual cranes, constructing a dual-machine synchronous source state dataset, and preprocessing the dual-machine synchronous source state dataset; S2, analyzing the delay change trend within the communication cycle based on the dual-machine synchronous source state dataset, determining the stability of the laser communication link, and outputting the link stability state; S3, introducing the link stability state and the boundary relationship of the control cycle, performing synchronization command arrival timing discrimination, and determining the effective alignment state of the synchronization control command in the control cycle; S4, performing a master-slave crane multi-axis operation consistency evaluation based on the effective alignment state, and outputting the synchronous adjustment control of the slave servo drive.

[0026] Specifically, the steps for collecting the basic data of dual-machine synchronous control directly generated during the synchronous operation of the dual cranes' multi-axis systems and constructing the dual-machine synchronous source state dataset are as follows: Collect the basic data of dual-machine synchronous control directly generated during the synchronous operation of the dual cranes' multi-axis systems, including the master system clock time and the slave system clock time. These are obtained in real-time by the high-precision clock units built into the master PLC and slave PLC during the motion control cycle, respectively. The timing resolution matches the delay level of the laser wireless communication and maintains microsecond-level accuracy. The master synchronization command sending trigger signal is generated by the master PLC through a high-speed task scheduling interrupt output when generating the multi-axis synchronous operation speed curve and writing it into the communication buffer. The slave communication... The signal reception interrupt trigger signal is generated by the slave PLC through a communication interrupt when the laser wireless communication unit completes the data frame reception and writes it into the communication buffer. The laser wireless communication data frame is sent by the master PLC to the laser wireless communication unit via the Ethernet interface and received by the slave-side optical receiving unit, then forwarded to the slave PLC communication interface. The data frame structure includes a frame header identifier, a time stamp, and a control load field, and maintains the same encoding method as the synchronous speed curve and position data. The communication status word is output by the internal register of the laser wireless communication unit and read within the PLC communication cycle, containing link delay T, communication status flag, and link stability indication information. The pulse counts of the encoders on each motion axis of the master PLC and the pulse counts of the encoders on each motion axis of the slave PLC are also included. The motion axis encoder pulse counts are acquired by incremental encoders mounted on the lifting and traveling axes via high-speed counting units, and the pulse count results correspond one-to-one with the actual displacement. The encoder sampling time interval is recorded by the PLC periodic timer at 1ms sampling intervals to support the calculation of speed and displacement changes. The control cycle counter count value is output by the PLC motion control cycle counter to identify the sequential position of each control cycle. All data includes the corresponding control cycle sequence number and system clock identifier, and bidirectional time stamp alignment is performed between the master PLC and slave PLC based on the link delay T returned by the laser wireless communication unit, with the slave system clock time determined accordingly. The link propagation time is corrected forward or backward to establish a correspondence between the host's transmitted time stamp and the slave's received time stamp under the same time base, thereby avoiding cross-clock alignment deviations introduced by independent master and slave clocks. A unified time series is established based on the host system clock time and the sequence is executed. Control cycle sequence number index and communication cycle sequence number index are established to form a stable mapping relationship between the arrival order of data frames within the communication cycle and the control cycle boundary. Laser wireless communication data frames and communication status words are bound frame by frame according to the time stamp. Link delay information is associated with and stored with the corresponding synchronization command data to construct a time-consistent, field-complete, and periodically indexed dual-machine synchronous source state dataset.

[0027] In this implementation scheme, the basic data for dual-machine synchronous control is aligned across clocks and reconstructed in a unified time base, so that a stable correspondence is formed between the control cycle and the communication cycle. The laser wireless communication link delay information and the synchronization command are consistently bound. The dual-machine synchronous source state dataset has temporal continuity and structural integrity, providing a highly consistent data foundation for link delay fluctuation characterization, command effective alignment discrimination, and multi-axis synchronous adjustment.

[0028] Specifically, the preprocessing steps for the dual-machine synchronous source state dataset are as follows: Based on the dual-machine synchronous source state dataset, a dual-time reference mapping relationship between the control cycle index and the communication cycle index is constructed. Considering the nonlinear scaling and local jitter of the laser link delay within adjacent cycles, a dynamic time warping algorithm is used to perform periodic-level alignment processing on the control link and the communication link, so that the instruction transmission sequence and the reception sequence under different time references establish the optimal matching path on the time axis, eliminating the periodic misalignment caused by delay fluctuations. Focusing on the characteristics of communication link delay fluctuations, for sudden abnormal delay points caused by optical alignment offset and environmental disturbances, a robust discreteness criterion is constructed using the median absolute deviation method to identify amplitude abnormal samples. At the same time, the local outlier factor algorithm is combined to characterize the change in temporal neighborhood density and identify structural outliers, completing the removal of abnormal time series points to avoid abnormal samples from participating in subsequent time series modeling. Based on the control cycle counter count, a unified cycle resampling process is performed on the multi-source time series to ensure that the encoder feedback sequence, communication delay sequence, and command trigger sequence form a consistent sampling structure under a unified control beat, guaranteeing the comparability of cross-source data. A range standardization method is used to standardize the dual-machine synchronous source dataset, mapping the original data with different physical dimensions to a unified numerical range and eliminating dimensional differences, allowing variables such as link delay, position, and velocity to participate in the analysis on the same scale. A max-min normalization method is used to normalize the dual-machine synchronous source dataset, further compressing all features into a dimensionless unified range, enabling the data amplitude to have consistent weighting in control calculations. This forms a continuous processing chain consisting of cycle alignment, anomaly removal, beat unification, and dimensionless processing, ensuring that the link delay fluctuation characterization results are stable and usable for subsequent synchronous control calculations.

[0029] In this implementation scheme, the dual-machine synchronous source state dataset completes the timing alignment of the control cycle and the communication cycle, the cycle misalignment is corrected, abnormal timing points are identified and eliminated, the multi-source time series maintain a consistent sampling structure under a unified control beat, the data amplitude is expressed in a dimensionless manner and has a unified scale, and the link delay fluctuation characteristics are stably characterized, providing a continuous and reliable data foundation for command activation alignment and multi-axis synchronous adjustment.

[0030] Specifically, the steps for analyzing the latency variation trend within a communication cycle based on a dual-machine synchronous source state dataset are as follows: First, read the host system clock time corresponding to the host synchronization command sending trigger signal, the slave system clock time corresponding to the slave communication reception interrupt trigger signal, and the control cycle counter count value to obtain the host sending time, slave receiving time, preceding sending time, and preceding receiving time. Second, parse the communication status word corresponding to the communication cycle sequence number index and extract the round-trip propagation time field. Then, perform a conversion process on the round-trip propagation time field, ensuring that the one-way propagation delay is equal to half the round-trip propagation time, to obtain the link latency time, making the link latency time consistent with the definition of the master-slave unidirectional transmission path. Third, filter the non-zero values ​​in the historical sequence of link latency time and perform numerical sorting. In the sorting results, introduce an anomaly suppression criterion based on the absolute deviation of the median to remove abnormally small values ​​below the statistical lower bound, and then select the smallest positive value from the remaining samples for fixed processing. The normalized stability compensation is obtained and stored in the parameter area. The minimum positive value corresponds to the shortest effective propagation time of the link in a stable propagation state, which is used to characterize the inherent transmission lower limit of the system and serve as a normalization benchmark to offset the impact of zero values ​​and abnormal disturbances on the stability of the denominator. The current cycle time difference is obtained by subtracting the master transmission time from the slave reception time. The previous cycle time difference is obtained by subtracting the previous transmission time from the previous reception time. The change in time difference is obtained by subtracting the previous cycle time difference from the current cycle time difference, which is used to characterize the dynamic change trend of link delay in adjacent communication cycles. The absolute value of the change in time difference is taken to obtain the change amplitude to characterize the intensity of delay fluctuation. The link delay time is added to the normalized stability compensation to obtain the normalization benchmark, which is used to construct a stable denominator structure with physical lower limit constraints. The change amplitude is divided by the normalization benchmark to obtain the link stability metric, so that the delay fluctuation can be quantitatively expressed on a unified scale and has cross-cycle comparability. The link stability metric is a ratio between the magnitude of the time difference change and the normalized baseline, which characterizes the relative intensity of delay fluctuations and is used to represent the stability of the communication link and support timing alignment control decisions.

[0031] The specific calculation method for the link stability metric is as follows: In the formula, This represents a link stability metric. Indicates the time when the host sends the message. Indicates the slave device's reception time. Indicates the preceding transmission time. Indicates the preceding reception time. Indicates the link delay time. This represents the normalized stable compensation amount.

[0032] In this implementation scheme, the link delay variation trend within the communication cycle is continuously characterized, the single-way link delay time is uniformly defined and round-trip measurement deviation is eliminated, the normalized stable compensation quantity establishes a stable propagation benchmark and suppresses abnormal small value interference, the time difference variation structure maintains a consistent expression across cycles, and the link stability measurement value has comparability and scale uniformity, providing a reliable basis for link stability state judgment and synchronization control beat constraints.

[0033] Specifically, the steps for determining the stability of the laser communication link and outputting its stable state are as follows: The link stability metric is compared in real-time with the link fluctuation threshold. When the link stability metric is less than the link fluctuation threshold, the current cycle's transmission time, reception time, and link delay time are written into the time base register, keeping the link delay compensation constant, maintaining the synchronous command transmission rhythm from the master PLC to the slave PLC constant, maintaining the control cycle boundary alignment reference constant, and writing the link stability metric into the link state buffer to ensure the time base relationship of the communication link remains stable during propagation. When the link stability metric is greater than or equal to the link fluctuation threshold, the laser communication link experiences sudden jitter or intermittent fluctuations in the current cycle caused by optical alignment offset, structural vibration, or propagation path disturbance. Obstruction can cause uncertain drift in the arrival time of data frames, potentially crossing the control cycle boundary. To address this, the link delay compensation in the time base register is rewritten based on the current cycle link delay time. The advance of the synchronization command is adjusted to the extended value corresponding to the link delay compensation, ensuring sufficient time margin for the synchronization command before entering the control cycle. This expands the cycle boundary capture width of the slave PLC for receiving the synchronization command result, allowing data frames arriving early or late under jitter conditions to still be effectively identified and included in the same cycle execution range. Simultaneously, the switching time of the synchronization speed curve issued by the master PLC in the current cycle is locked, preventing the speed curve switching action from drifting with link jitter. This avoids cross-cycle misalignment of synchronization commands caused by link instability and maintains the consistency of multi-axis operation.

[0034] In this implementation scheme, the link stability status is classified and determined. The stable interval maintains the consistency of the control cycle boundary and the continuity of the command transmission rhythm. The fluctuating interval forms a coordinated constraint of advance extension and acquisition width relaxation. The speed curve switching time is kept locked. The command drift caused by sudden jitter and intermittent blockage is absorbed. The disturbance of communication instability to the control rhythm is suppressed.

[0035] Specifically, the following steps are taken to determine the timing of synchronization commands by introducing the relationship between link stability and control cycle boundaries: First, read the count transition position corresponding to the control cycle counter value and match it with the host system clock time to complete the cycle start point time calibration, obtaining the control cycle boundary time so that the control cycle has a unified time reference. Second, extract the link stability metric value from the link state buffer. After pre-processing normalization, the link stability metric value has been converted into a dimensionless expression, used to characterize the influence weight of link fluctuation intensity on timing determination. Third, call the normalized stability compensation amount based on the parameter area. The normalized stability compensation amount corresponds to the minimum effective time reference under stable link propagation, used to maintain the stability of the denominator value. Fourth, obtain the slave receiving time and link delay time so that the actual arrival time of the synchronization command is... The time difference is determined by link propagation characteristics and the location of the instruction. The time difference is obtained by subtracting the slave reception time from the control cycle boundary time, which characterizes the remaining time margin of the instruction arrival time relative to the cycle boundary. The link delay time is added to the normalized stability compensation amount, and the denominator is used to calculate the time difference ratio, transforming the time difference into a dimensionless proportional quantity on a unified time scale. The link stability metric is negativeized and exponentially amplified to obtain an attenuation term, ensuring that the impact of link fluctuations on timing judgment has an exponentially decreasing relationship while maintaining a dimensionless expression. The time difference ratio is multiplied by the attenuation term to obtain the instruction alignment determination value, coupling the instruction arrival margin and link stability within the same dimensionless space, thus characterizing the effectiveness reliability of synchronization instructions within the control cycle. The instruction alignment determination value, formed by coupling the time difference ratio and the link stability attenuation term, is unified into a dimensionless quantity, comprehensively representing the combined effect of instruction arrival margin and link fluctuations on effectiveness reliability.

[0036] The specific calculation method for the instruction alignment determination value is as follows: In the formula, This indicates the alignment determination value of the instruction. Indicates the boundary time of the control cycle. Indicates the slave device's reception time. Indicates the link delay time. This represents the normalized stable compensation amount. This represents a link stability metric.

[0037] In this implementation scheme, the control cycle boundary and the instruction arrival time form a unified reference relationship, the stable state of the link participates in the timing constraint, the time margin completes the dimensionless expression and is coupled with the link fluctuation intensity, and the instruction alignment judgment value realizes the quantitative discrimination under the consistent scale across cycles, ensuring that the effective position of the synchronization instruction has stability and comparability.

[0038] Specifically, the steps for determining the effective alignment status of the synchronization control command in the control cycle are as follows: The command alignment determination value is compared with the alignment threshold in real time. The alignment threshold includes a primary alignment threshold and a secondary alignment threshold. When the command alignment determination value is less than the primary alignment threshold, the arrival time of the current synchronization command has insufficient margin relative to the control cycle boundary. After the command is loaded within the current cycle, it may experience cross-cycle execution offset. The dequeue action of the current cycle synchronization command in the command buffer is frozen, the slave servo driver's execution speed curve of the previous control cycle is maintained, the current synchronization command is written into the pre-loading area of ​​the next cycle, and the effective time of the current control cycle is reset, so that the command is delayed until the complete cycle. When the command alignment determination value is greater than or equal to the primary alignment threshold and less than the secondary alignment threshold, the arrival time of the current synchronization command is near the cycle boundary and has limited loading margin. The current synchronization command is written into the cycle end buffer, and the synchronization command loading is performed at a fixed sampling point before the end of the current control cycle. The sampling point corresponds to the end time position within the control cycle and is triggered by the PLC cycle timer at the end of the cycle, ensuring a fixed time interval between the loading action and the end boundary of the cycle. The effective time of the synchronization command is rewritten as the end alignment time of this cycle. The end alignment time of this cycle corresponds to the trigger time of the fixed sampling point and serves as the reference for the last effective loading time within the cycle. At the same time, the acquisition cycle of master and slave axis displacement, position, and speed is switched to a dense refresh sampling cycle. The dense refresh sampling cycle corresponds to shortening the sampling time interval at the end of the cycle to improve the initial error observation resolution after alignment. When the command alignment judgment value is greater than or equal to the secondary alignment threshold, the arrival time of the current synchronization command is located in the early part of the control cycle and has sufficient loading margin. The dequeue restriction of the synchronization command in the command buffer area is released, the synchronization speed curve segment is written into the slave trajectory register area, and loaded into the slave servo driver reference input terminal according to the boundary time of the current control cycle, so that the command directly participates in the control output at the beginning position of the current cycle. At the same time, the command alignment judgment value is written into the effective status area.

[0039] In this implementation scheme, the synchronous control commands form a hierarchical effective alignment state within the control cycle, the loading position within the cycle is constrained and rearranged, the execution consistency at the cycle boundary is maintained, the loading of commands near the boundary has a stable time base, the commands that arrive in advance directly participate in the control output, cycle misalignment and execution drift are suppressed, and the multi-axis running cycle remains continuous and consistent.

[0040] Specifically, the steps for performing a multi-axis operation consistency assessment of the master and slave cranes based on the effective alignment status are as follows: Read the encoder pulse counts of each motion axis of the master crane, the encoder pulse counts of each motion axis of the slave crane, and the encoder sampling time interval; perform displacement conversion to obtain the current position of the master axis and the current position of the slave axis; calculate the difference in encoder pulse counts of each motion axis of the master crane within two adjacent sampling periods and perform differential conversion in conjunction with the encoder sampling time interval to obtain the operating speed of the master axis; calculate the difference in encoder pulse counts of each motion axis of the slave crane within two adjacent sampling periods and perform differential conversion in conjunction with the encoder sampling time interval to obtain the operating speed of the slave axis; extract the instruction alignment judgment value from the effective status area; call the normalized stability compensation amount based on the parameter area, reconstruct the normalized stability compensation amount into a stable regularization term in the velocity dimension, and place it in a physical dimension space consistent with the velocity difference, in order to suppress low-speed or zero-speed states. The value of the denominator approaching zero in the current state is unstable; the position difference is obtained by subtracting the current position of the slave axis from the current position of the master axis; the speed difference is obtained by subtracting the speed of the slave axis from the speed of the master axis; the speed difference is squared and added to the normalized stable compensation quantity with the same speed dimension to obtain the square root term, so that the square root term has the same physical meaning under the speed square dimension and reflects the combined effect of speed difference amplitude and stability constraint; the square root term is squared to obtain the normalized denominator, so that the denominator corresponds to the stable estimate of speed amplitude and avoids the amplification effect caused by speed approaching zero; the position difference is divided by the normalized denominator to obtain the position-speed ratio, so that the position deviation is normalized in the speed scale; the position-speed ratio is multiplied by the command alignment judgment value to obtain the synchronization adjustment drive value, so that the spatial deviation and the timing alignment reliability form a coupled adjustment quantity and are used for subsequent multi-axis synchronous control adjustment. The synchronous adjustment driving value is formed by the coupling of position difference and velocity normalization and alignment constraint. It has consistent dimensions and stable regularity, and is used to characterize the comprehensive adjustment intensity of deviation and timing reliability.

[0041] The specific calculation method for the synchronous adjustment driving value is as follows: In the formula, Indicates synchronous adjustment of drive value, Indicates the current position of the host axis. Indicates the current position of the slave axis. Indicates the operating speed of the main spindle. Indicates the speed of the driven shaft. This represents the normalized stable compensation amount. This indicates the alignment determination value for the instruction.

[0042] Table 1 shows the synchronous adjustment drive value data table provided in the embodiments of this application. For adjustment 1, the current position of the master axis is set to 5.20, the current position of the slave axis is set to 4.00, the master axis running speed is set to 10.00, the slave axis running speed is set to 10.00, the normalized stability compensation is set to 0.25, and the command alignment judgment value is set to 1.00; for adjustment 2, the current position of the master axis is set to 6.30, the current position of the slave axis is set to 4.30, the master axis running speed is set to 11.00, the slave axis running speed is set to 10.00, the normalized stability compensation is set to 0.25, and the command alignment judgment value is set to 0.90; for adjustment 3, the current position of the master axis is set to 7.10, the current position of the slave axis is set to 5.10, and the master axis running speed is set to 9. .00, the slave spindle running speed is set to 9.00, the normalization stability compensation is set to 0.25, and the command alignment judgment value is set to 1.00; the current position of the master spindle of adjustment 4 is set to 8.40, the current position of the slave spindle is set to 5.40, the master spindle running speed is set to 13.00, the slave spindle running speed is set to 12.00, the normalization stability compensation is set to 0.25, and the command alignment judgment value is set to 0.90; the current position of the master spindle of adjustment 5 is set to 7.80, the current position of the slave spindle is set to 5.00, the master spindle running speed is set to 8.00, the slave spindle running speed is set to 8.00, the normalization stability compensation is set to 0.25, and the command alignment judgment value is set to 1.00.

[0043] Table 1 Synchronous Adjustment Drive Value Data Table

[0044] like Figure 3 The figure shows the distribution of synchronization adjustment drive values ​​provided in the embodiments of this application. According to the data in the image and table, the synchronization adjustment drive values ​​corresponding to the five sets of adjustments are distributed between 1.61 and 5.60, exhibiting an overall fluctuating characteristic. The synchronization adjustment drive value of adjustment 5 is 5.60, the highest among all adjustments, indicating that the combined effect of master-slave position deviation and speed difference is strong under this adjustment condition, requiring a significant amount of synchronization correction. The synchronization adjustment drive value of adjustment 3 is 4.00, at a relatively high level, indicating that there is still a significant synchronization deviation under this state, requiring continuous adjustment. The synchronization adjustment drive values ​​of adjustment 1 and adjustment 4 are 2.40 and 2.41 respectively, close in value, indicating that the synchronization deviation is at a moderate level under the corresponding operating conditions, and the system is within a controllable adjustment range. The synchronization adjustment drive value of adjustment 2 is 1.61, the lowest value, indicating a high degree of matching between master-slave axis position and speed, and a relatively stable synchronization state. This figure can intuitively reflect the distribution of synchronization adjustment intensity under different adjustment conditions, and can be used to determine the current synchronization error level and adjustment requirements, providing a basis for the implementation of subsequent speed correction and displacement compensation strategies.

[0045] In this implementation scheme, the consistency assessment of multi-axis operation of the master and slave cranes forms a deviation expression under a unified dimension. Position deviation and speed difference are stably coupled, numerical stability is maintained at low speed, alignment reliability participates in the construction of adjustment weights, synchronous adjustment drive values ​​have continuity and directional consistency, and multi-axis operation deviation is controllably compressed and supports subsequent fine adjustment.

[0046] Specifically, the synchronous adjustment control steps of the output slave servo drive are as follows: The synchronous adjustment drive value is used as the synchronous compensation input of the slave servo drive. The synchronous adjustment drive value is converted into the speed correction component of the corresponding motion axis of the slave based on the calibration coefficient of the servo drive speed setting interface and superimposed on the current speed curve output value, so that the compensation amount forms a continuous superposition based on the original speed planning. When the synchronous adjustment drive value is greater than zero, the output speed of the corresponding motion axis of the slave is increased and the current position following error correction cycle is compressed, so that the slave motion trajectory converges towards the master side. When the synchronous adjustment drive value is less than zero, the output speed of the corresponding motion axis of the slave is decreased and the current position compensation step size is released, so that the slave motion cycle is slowed down to eliminate the lead deviation. After the speed correction component is written to the driver setting terminal, the slave displacement parameter is adjusted according to the current position feedback. The system performs unidirectional compensation to ensure that speed adjustment and position correction maintain the same direction and avoid control direction conflicts. After completing one compensation output, the displacement, position, and speed of each axis of the master and slave are sampled back. The position difference is recalculated, and the output speed and displacement reference values ​​of the slave servo driver are continuously rewritten based on the updated synchronous adjustment drive value, forming a closed-loop progressive adjustment process. The error threshold is used to define the allowable range of the master-slave position difference. The error threshold is based on the absolute value sequence of synchronous errors in historical operating data. The 95th percentile statistical result is used as the threshold benchmark and is corrected in combination with the minimum resolvable displacement accuracy of the servo system. This ensures that the threshold covers most normal operating errors while avoiding excessive relaxation of the control boundary. When the position difference is less than or equal to the error threshold, the speed correction component and displacement compensation component are canceled, allowing the slave to return to the original speed curve control state.

[0047] In this implementation scheme, synchronous adjustment control forms a continuous closed-loop adjustment process on the slave servo drive side. Speed ​​correction and displacement compensation remain in the same direction. Position deviation gradually converges during the adjustment process. The adjustment intensity is dynamically adjusted with the change of deviation. Error threshold constraint makes the control convergence boundary clear. The multi-axis operation state is restored to coordination and consistency within the accuracy range.

[0048] like Figure 2The diagram shows a schematic of a laser communication-based multi-axis synchronous control system for dual cranes provided in this application embodiment. This system utilizes a laser communication-based multi-axis synchronous control method for dual cranes, including: a source state acquisition module for acquiring basic data of dual-machine synchronous control directly generated during the multi-axis synchronous operation of the dual cranes. Data sources cover the clock timing units of the master PLC and slave PLC, data frames and communication status word registers of the laser wireless communication unit, and incremental encoders and high-speed counting units of each motion axis. This constructs a dual-machine synchronous source state dataset, which is then preprocessed to form a unified time reference and consistent sampling structure; and a link stability identification module for identifying the link stability of the dual cranes. The step-source dataset analyzes the latency variation trend within the communication cycle, transforming the latency variation characteristics between adjacent cycles into a stability measurement result, determining the stability of the laser communication link, and outputting the link stability state. The command activation alignment module introduces the link stability state and control cycle boundary relationship, matching the arrival time and position of synchronization commands with the control cycle boundary, performing synchronization command arrival timing judgment, and determining the activation alignment state of the synchronization control command within the control cycle, ensuring that the command loading position is consistent with the control cycle. The multi-axis synchronous adjustment module performs a master-slave crane multi-axis operation consistency assessment based on the activation alignment state, coupling position deviation and speed difference to form an adjustment input, and outputting synchronous adjustment control driven by the slave servo to achieve dynamic compression of multi-axis collaborative operation errors.

[0049] In this implementation scheme, the source state acquisition module, link stability identification module, command activation alignment module and multi-axis synchronous adjustment module form a continuous closed-loop control path. The communication timing is consistent with the control cycle. The multi-axis operation status has a unified time base and consistent adjustment logic. The impact of link fluctuations is constrained. The synchronous adjustment control continues to converge. The accuracy of multi-axis collaborative operation remains stable.

[0050] like Figure 4The image shows the phase space trajectory of link delay fluctuations provided in this embodiment. Based on the distribution of sampling points and the trajectory connections in the image, it can be seen that the link delay difference between adjacent control cycles alternates between negative and positive regions, exhibiting a clear cross-quadrant transition characteristic. This indicates that the link delay exhibits dynamic fluctuations rather than a unidirectional trend within continuous cycles. Specifically, points k=6 and k=9 are located in the second quadrant, indicating that the delay difference in the previous cycle was negative while the delay difference in the current cycle is positive, reflecting a change in delay from decreasing to increasing. Points k=2 and k=5 are located in the fourth quadrant, indicating that the delay changed from increasing to decreasing, reflecting a callback behavior in the link delay. Points k=4 and k=10 are concentrated in the first quadrant, indicating that the delay difference remains positive within continuous cycles, and the link exhibits a continuous increasing trend. K=11 is located near the boundary of the fourth quadrant, indicating that the delay change amplitude has decreased but is still in the adjustment phase. K=12, k=13, and k=14 are located in the third quadrant, indicating that the delay continuously decreases within continuous cycles and the direction of change is consistent. The overall trajectory shows a closed loop trend, indicating that the link delay fluctuation has periodic characteristics and a certain stable constraint range. This figure can intuitively reflect the dynamic evolution of the link delay between adjacent control cycles, and can be used to judge the link stability and fluctuation intensity, providing a basis for subsequent link stability identification and command alignment control.

[0051] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0052] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for multi-axis synchronous control of dual cranes based on laser communication, characterized in that, Includes the following steps: S1: Collect the basic data of dual-machine synchronous control directly generated during the synchronous operation of the dual cranes with multiple axes, construct the dual-machine synchronous source state dataset, and preprocess the dual-machine synchronous source state dataset; collect the basic data of dual-machine synchronous control directly generated during the synchronous operation of the dual cranes with multiple axes, including the master system clock time, slave system clock time, master synchronization command sending trigger signal, slave communication receiving interruption trigger signal, laser wireless communication data frame, communication status word, pulse count of each motion axis encoder of the master, pulse count of each motion axis encoder of the slave, encoder sampling time interval, and control cycle counter count value; S2, based on the dual-machine synchronous source state dataset, analyzes the delay change trend within the communication cycle, determines the stability of the laser communication link, and outputs the link stability status; Read the host system clock time corresponding to the host synchronization command sending trigger signal, the slave system clock time corresponding to the slave communication receiving interrupt trigger signal, and the control cycle counter count value to obtain the host sending time, slave receiving time, preceding sending time, and preceding receiving time; parse the communication status word corresponding to the communication cycle sequence number index and extract the round-trip propagation time field, convert the round-trip propagation time field according to the one-way propagation delay to obtain the link delay time; The non-zero values ​​in the historical sequence of link delay time are filtered and sorted numerically. The smallest positive value is selected for fixed processing to obtain the normalized stability compensation amount, which is then saved to the parameter area. The current period time difference is obtained by subtracting the master transmission time from the slave reception time. The previous period time difference is obtained by subtracting the previous transmission time from the previous reception time. The change in time difference is obtained by subtracting the previous period time difference from the current period time difference. The absolute value of the change in time difference is taken to obtain the change amplitude. The link delay time is added to the normalized stability compensation amount to obtain the normalization benchmark. The change amplitude is divided by the normalization benchmark to obtain the link stability metric. S3 introduces the link stability state and control cycle boundary relationship, performs synchronization command arrival timing discrimination, and determines the effective alignment state of the synchronization control command in the control cycle; reads the count transition position corresponding to the control cycle counter count value and matches it with the host system clock time to complete the cycle start point time calibration, obtaining the control cycle boundary time; extracts the link stability metric value from the link state buffer; calls the normalized stability compensation amount based on the parameter area; obtains the slave receiving time and link delay time; subtracts the slave receiving time from the control cycle boundary time to obtain the time difference; adds the link delay time to the normalized stability compensation amount and uses it as the denominator to perform ratio calculation on the time difference to obtain the time difference ratio; negativens the link stability metric value and performs exponential operation to obtain the attenuation term; multiplies the time difference ratio by the attenuation term to obtain the command alignment determination value; S4: Based on the effective alignment status, perform a multi-axis operation consistency assessment of the master and slave cranes, and output synchronous adjustment control for the slave servo drive; read the encoder pulse counts of each motion axis of the master crane, the encoder pulse counts of each motion axis of the slave crane, and the encoder sampling time interval, perform displacement conversion, and obtain the current position of the master axis and the current position of the slave axis; calculate the difference in encoder pulse counts of each motion axis of the master crane within two adjacent sampling periods and perform differential conversion in combination with the encoder sampling time interval to obtain the running speed of the master axis; calculate the difference in encoder pulse counts of each motion axis of the slave crane within two adjacent sampling periods and perform differential conversion in combination with the encoder sampling time interval to obtain the running speed of the slave axis; extract the instruction alignment judgment value from the effective status area; call the normalized stability compensation amount based on the parameter area; subtract the current position of the slave axis from the current position of the master axis to obtain the position difference; subtract the running speed of the slave axis from the running speed of the master axis to obtain the speed difference; The square of the speed difference is added to the normalized stable compensation value to obtain the square root inner term; the square root of the square root inner term is then performed to obtain the normalized denominator; the position difference is divided by the normalized denominator to obtain the position-speed ratio; the position-speed ratio is multiplied by the command alignment determination value to obtain the synchronization adjustment drive value.

2. The method for multi-axis synchronous control of dual cranes based on laser communication according to claim 1, characterized in that: The specific steps for collecting the basic data for dual-machine synchronous control directly generated during the synchronous operation of dual cranes with multiple axes and constructing the dual-machine synchronous source state dataset are as follows: All data are accompanied by corresponding control cycle numbers and system clock identifiers; a unified time series is established based on the host system clock time and the execution order is arranged; control cycle number index and communication cycle number index are established; laser wireless communication data frames and communication status words are associated and bound to each other; and a dual-machine synchronous source state dataset is constructed.

3. The method for multi-axis synchronous control of dual cranes based on laser communication according to claim 1, characterized in that: The specific steps for preprocessing the dual-machine synchronous source state dataset are as follows: Based on the dual-machine synchronous source dataset, a dual-time reference mapping relationship between the control cycle index and the communication cycle index is constructed. The dynamic time warping algorithm is used to perform periodic alignment processing on the control link and the communication link. Based on the delay fluctuation characteristics of the communication link, the median absolute deviation method and the local outlier factor algorithm are used to identify and remove abnormal time series points. The multi-source time series are subjected to unified periodic resampling processing based on the control cycle counter count value. The range standardization method is used to perform standardization processing on the dual-machine synchronous source dataset. The max-min normalization method is used to perform normalization processing on the dual-machine synchronous source dataset.

4. The method for multi-axis synchronous control of dual cranes based on laser communication according to claim 1, characterized in that: The specific steps for determining the stability of the laser communication link and outputting the link stability status are as follows: The link stability metric is compared with the link fluctuation threshold in real time; When the link stability metric is less than the link fluctuation threshold, the current cycle transmission time, reception time and link delay time are written into the time base register area, the link delay compensation amount remains unchanged, the synchronous instruction transmission rhythm of the master PLC to the slave PLC remains unchanged, the control cycle boundary alignment reference remains unchanged, and the link stability metric is written into the link status buffer area. When the link stability metric is greater than or equal to the link fluctuation threshold, the link delay compensation amount in the time base register is rewritten according to the current cycle link delay time. The advance amount of the synchronization command taking effect is adjusted to the extended value corresponding to the link delay compensation amount. The cycle boundary capture width of the slave PLC for receiving the synchronization command result is extended, and the switching time of the synchronization speed curve issued by the master PLC in the current cycle is locked.

5. The method for multi-axis synchronous control of dual cranes based on laser communication according to claim 1, characterized in that: The specific steps for determining the effective alignment status of the synchronization control command in the control cycle are as follows: The instruction alignment determination value is compared with the alignment threshold in real time, and the alignment threshold includes a first-level alignment threshold and a second-level alignment threshold. When the instruction alignment judgment value is less than the first-level alignment threshold, the dequeue action of the current cycle synchronization instruction in the instruction buffer is frozen, the slave servo driver maintains the speed curve of the previous control cycle, the current synchronization instruction is written into the preload area of ​​the next cycle and the effective time of the current control cycle is reset. When the command alignment judgment value is greater than or equal to the first-level alignment threshold and less than the second-level alignment threshold, the current synchronization command is written into the buffer at the end of the cycle. The synchronization command is loaded at the fixed sampling point before the end of the current control cycle, and the effective time of the synchronization command is rewritten to the end alignment time of this cycle. At the same time, the acquisition cycle of master and slave axis displacement, position and speed is switched to dense refresh sampling cycle. When the instruction alignment determination value is greater than or equal to the secondary alignment threshold, the dequeue restriction of the synchronization instruction in the instruction buffer is released, the synchronization speed curve segment is written into the slave trajectory register area, and loaded into the slave servo driver reference input terminal according to the current control cycle boundary time. At the same time, the instruction alignment determination value is written into the effective status area.

6. The method for multi-axis synchronous control of dual cranes based on laser communication according to claim 1, characterized in that: The specific steps for the synchronous adjustment and control of the output slave servo drive are as follows: The synchronous adjustment drive value is called as the synchronous compensation input of the slave servo driver, and the synchronous adjustment drive value is converted into the speed correction component of the corresponding motion axis of the slave and superimposed on the current speed curve output value. When the synchronous adjustment drive value is greater than zero, the output speed of the corresponding motion axis of the slave is increased and the current position following error correction cycle is compressed. When the synchronous adjustment drive value is less than zero, the output speed of the corresponding motion axis of the slave is reduced and the current position compensation step size is released. After the speed correction component is written to the driver's setpoint, the slave displacement reference value is compensated in the same direction according to the current position feedback. After completing one compensation output, the displacement, position and speed of each axis of the master and slave are sampled back, the position difference is recalculated and the slave servo driver output speed and displacement reference value is continuously rewritten according to the updated synchronous adjustment drive value until the position difference is less than or equal to the error threshold, and then the speed correction component and displacement compensation component are cancelled.

7. A dual-crane multi-axis synchronous control system based on laser communication, employing the dual-crane multi-axis synchronous control method based on laser communication as described in any one of claims 1-6, characterized in that, include: Run the source state acquisition module to collect the basic data of dual-machine synchronous control directly generated during the synchronous operation of dual cranes with multiple axes, construct the dual-machine synchronous source state dataset, and preprocess the dual-machine synchronous source state dataset; The link stability identification module is used to analyze the delay change trend within the communication cycle based on the dual-machine synchronous source state dataset, determine the stability of the laser communication link, and output the link stability status. The command effective alignment module is used to introduce the link stability state and control cycle boundary relationship, perform synchronization command arrival timing judgment, and determine the effective alignment state of the synchronization control command in the control cycle. The multi-axis synchronous adjustment module is used to perform a master-slave crane multi-axis operation consistency assessment based on the effective alignment status, and output synchronous adjustment control of the slave servo drive.

Images