Servo control method and system based on programmable logic controller

Abstract

The invention relates to the field of servo control, and particularly discloses a servo control method and system based on a programmable logic controller. The method comprises the following steps: the main control module and the shaft control module complete communication initialization through a high-speed bus, and load a standardized instruction library to generate an adaptive program segment; the digital twin engine collects data in real time to construct a virtual model, and when the deviation exceeds a threshold value, early warning is triggered; when a fault occurs, the feature parameters are matched with the fault gene pool to judge the type, and a maintenance work order is generated; and hot plug maintenance is supported, and parameters are quickly synchronized to recover operation after a new module is inserted. According to the technology, through modularization and intelligent integration, multi-axis flexible expansion is achieved, frequent hardware change is not needed, the maintenance process is optimized, faults are rapidly positioned, a main system is not interrupted, the whole process is traceable, meanwhile, system stability and control precision are guaranteed, and the flexible requirement of industrial multi-axis cooperation is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of servo control, in particular to a servo control method and system based on a programmable logic controller. BACKGROUND

[0002] In modern industrial automation production systems, the servo control system as the core unit to realize precise motion control, its performance directly determines the running accuracy and efficiency of the production line. With the rapid development of intelligent manufacturing, the demand for multi-axis collaborative control of industrial equipment is increasingly urgent, for example, in the scene of numerical control machine tool, automation assembly line, robot workstation, dozens or even hundreds of servo axes are often needed to realize synchronous linkage to complete complex trajectory planning and action execution. Under this background, the servo control scheme based on programmable logic controller (PLC) has become the mainstream choice in the industrial field because of its high reliability and strong anti-interference. However, the traditional PLC architecture gradually exposes the technical limitations that are difficult to overcome when dealing with multi-axis expansion needs: At the hardware level, when the number of servo axes increases, the I / O points and pulse output modules of the PLC need to be expanded simultaneously, which leads to the continuous rise of the system bus load, which is easy to break through the running threshold. In order to maintain system operation, frequent addition of pulse output modules, communication interface modules and other hardware components is needed, which not only significantly increases the cost of equipment procurement and deployment, but also reduces the system redundancy due to the increased correlation between modules - the failure of a single module may cause bus communication interruption, and thus lead to the shutdown of the whole system, which seriously affects the production continuity. At the maintenance level, the fault correlation of PLC logic program, servo driver and signal transmission line in the traditional architecture is very strong, which increases the complexity of problem troubleshooting. For example, PLC pulse output abnormality may be misjudged as servo encoder failure, and driver alarm may also be caused by program instruction error or poor line contact. Maintenance personnel need to check program instruction output, driver alarm code, line on-off state and other multi-dimensional information, which not only consumes time and effort, but also easily delays the fault handling period due to misjudgment. The above problems become increasingly prominent with the expansion of the number of axes of industrial equipment, and have become a key bottleneck restricting the development of intelligent manufacturing towards high flexibility and high reliability. Therefore, it is an urgent need in the field of industrial automation to develop a PLC servo control technology that can efficiently support multi-axis expansion and simplify maintenance process. SUMMARY

[0003] The purpose of the present application is to overcome the defects of the prior art, and to provide a servo control method based on a programmable logic controller, and to provide a servo control system based on a programmable logic controller, to solve the problems raised in the background art.

[0004] A servo control method based on a programmable logic controller, comprising the steps of: The main control module identifies a plurality of axis control modules through a high-speed bus, assigns a unique identifier to each axis control module and binds communication, the axis control module sends hardware parameters to the main control module, and the main control module completes communication initialization after verification; The main control module loads a standardized instruction library, receives servo axis parameters input by a data interaction interface, generates an axis control program segment and sends it to the corresponding axis control module, the axis control module verifies the program segment and stores it, and feeds back an adaptation completion signal; The digital twin engine periodically collects axis control module, driver and encoder data to construct a virtual model; compares real-time data with a normal model, and when the deviation coefficient exceeds a first threshold value, the main control module marks an abnormal component and triggers a warning; The axis control module uploads running parameters, and when a fault occurs, the main control module extracts characteristic parameters and matches them with a fault gene library, and when the matching degree exceeds a second threshold value, the fault type is determined, and a maintenance work order containing the fault position, component model and operation steps is generated; The maintenance personnel issue a module isolation instruction through a human-machine interface, and the main control module receives the instruction and isolates the target axis control module; After a new module is inserted, the main control module sends configuration parameters to complete synchronization, restores bus connection and records running data.

[0005] Further, the main control module scans and identifies the connected axis control modules one by one through the back high-speed bus, obtains the inherent hardware identifier of each axis control module, assigns a unique identifier to each module according to the cascade order of the axis control modules, and stores the unique identifier in association with the inherent hardware identifier of the module; a point-to-point communication link between the main control module and each axis control module is established through the fiber optic communication interface of the axis control module, communication binding is completed, and it is ensured that the main control module can send instructions to the corresponding axis control module and receive feedback information through the unique identifier.

[0006] Further, the axis control module transmits hardware parameters to the main control module through the back high-speed bus, including the signal type and voltage level of the I / O interface integrated therein, the maximum frequency and pulse equivalent of the pulse output channel, the communication protocol version of the fiber optic communication interface, and the model adaptation information of the corresponding servo driver and the protection threshold parameter of the built-in power management unit; after receiving the parameters, the main control module first checks whether the module model is within the cascade allowed range, then verifies whether the fiber optic communication interface parameters and the communication standard of the back high-speed bus are consistent, simultaneously confirms the compatibility of the power management unit parameters and the system total power supply specification, and after verification, the main control module sends a synchronization instruction to the axis control module, the axis control module starts the bidirectional verification of the fiber optic communication link, completes the negotiation of the data transmission encryption protocol and the alignment of the clock reference, and finally the main control module records the communication link state of the axis control module in the system registry, completing the initialization process.

[0007] Further, the main control module loads the built-in standardized control instruction library after power-on, which contains axis start / stop, speed regulation basic instructions, and multi-axis synchronization, interpolation linkage composite instructions. Specifically, the standardized control instruction library is stored in a modular data structure, the basic instructions contain the level trigger signal parameters of axis start / stop, the PID parameter configuration interval of speed regulation, and the encoder zeroing instruction format of position calibration, and the composite instructions include the phase compensation algorithm parameters of multi-axis synchronization and the trajectory planning formula of interpolation linkage.

[0008] Further, the digital twin engine takes the main control module as the data aggregation core, acquires full-dimensional data through three-layer acquisition links, and constructs a high-fidelity virtual mapping model based on hardware characteristics, as follows: Axis control module data, real-time state of I / O interface, real-time frequency and pulse count of pulse output channel, real-time delay and packet loss rate of fiber communication interface, output voltage of built-in power management unit, and module temperature are collected in real time through the back high-speed bus; Servo driver data, real-time output current, bus voltage, IGBT module temperature, running mode, and real-time alarm word of the driver are synchronously collected through the fiber communication interface solidified by the axis control module; Encoder data, real-time position value, speed value, acceleration, and signal integrity index of absolute encoder are collected in differential signal reception mode; The high-precision clock of the main control module is used as a reference to achieve system time synchronization through IEEE1588 PTP protocol; the axis control module, the driver, and the encoder are all configured with hardware timestamp units, and the data collection automatically adds time labels to ensure time synchronization of the three-way data; The original data is first preprocessed locally by the axis control module, the pulse signal is anti-jitter filtered, the current / voltage curve is peak suppressed, and the encoder position value is parity checked and jump detected; the preprocessed data is transmitted to the main control module through an encrypted channel, and finally hashed into blocks according to the unique identifier and timestamp of the axis control module, and stored in the ring buffer of the main control module.

[0009] Further, the virtual model adopts a "system-module-component" three-level architecture. Specifically, the system-level model restores the physical layout of the entire control matrix in a three-dimensional scene, including the installation positions of the main control module and the axis control module on the guide rail, the connection topology of the optical fiber and the bus, and the spatial distribution of the servo axis; in the module-level model, each axis control module corresponds to an independent virtual node, which real-time maps the waveform simulation of its pulse output, the state indicator light of the I / O interface, and the energy flow simulation of the power management unit; in the component-level model, the virtual entities of the driver and the encoder are subdivided, the driver model real-time simulates the IGBT switch state, and the encoder model inverses the dynamic characteristics of the mechanical transmission chain through position data.

[0010] Further, the comparison of real-time data and normal model includes: the digital twin engine compares the pre-processed real-time data with the normal working condition model in layers, calculates the weighted sum of the deviation coefficients of different parameters as the final comprehensive deviation coefficient.

[0011] Further, the uploading of the running parameters by the axis control module includes: the axis control module uploads the running parameters through the optical fiber communication interface and the back high-speed bus double-channel parallel, and the uploading adopts a "period + trigger" double mode.

[0012] Further, the matching of the feature parameters extracted by the main control module with the fault gene library includes: when a fault occurs, the main control module immediately retrieves the real-time running parameters uploaded by the axis control module through the optical fiber communication interface and the back high-speed bus, and extracts the comprehensive deviation coefficient and the key parameter deviation value generated by the digital twin engine, and integrates them to form a feature parameter set; the extracted feature parameters are standardized to unify different types and different orders of magnitude of the feature parameters into standardized values that can be directly compared, ensuring that the matching calculation with the feature combination in the fault gene library can be performed. The fault gene library is stored in a distributed database architecture, integrates historical fault handling records, equipment manufacturer maintenance manual data, and virtual fault cases generated by digital twin simulation, and forms a feature data set covering common faults; each fault entry contains a feature parameter combination, a dynamic weight matrix, a historical matching probability, a fault evolution chain, and associated component information; the main control module compares the standardized feature parameters with the feature combinations of each fault entry in the gene library one by one, and calculates the matching degree.

[0013] Furthermore, when the matching calculation result exceeds the preset second threshold, the main control module immediately determines the fault type corresponding to the matching result as the final type of the current fault; then the maintenance work order generation process is started, and the three-dimensional spatial coordinates of the faulty component are extracted from the three-level virtual model of the digital twin engine, where the position of the axis control module is accurate to its installation slot number on the guide rail and associated with its unique identifier; the position of the servo drive is marked on the specific shelf coordinates of the equipment rack, and the encoder corresponds to the specific joint point of the mechanical transmission chain; the component model information is retrieved from the hardware parameter library of the main control module, and the operation steps are generated according to the timing logic of fault handling.

[0014] Beneficial effects of the present invention: Through the deep integration of modular architecture and intelligent technology, this technology achieves efficient expansion of multi-axis servo control and significant optimization of maintenance processes, while ensuring the stability and control accuracy of system operation throughout the entire process.

[0015] The multi-axis expansion capability has achieved a qualitative improvement, and the number of servo axes can be flexibly adjusted according to actual production needs. The expansion process does not need to rely on frequent hardware changes. The overall operating performance of the system remains stable, effectively meeting the flexible needs of multi-axis collaborative control in industrial scenarios.

[0016] The maintenance process has been fundamentally innovated. With the help of intelligent diagnostic mechanisms, the source of the fault and related components can be quickly and accurately located. Maintenance operations do not require interruption of the main system operation, significantly shortening the fault handling time. At the same time, through full-process data recording, fault traceability is achieved, providing support for subsequent analysis and prevention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The flowchart of the servo control method based on a programmable logic controller of the present invention is shown in FIG. DETAILED DESCRIPTION

[0018] This application is based on a servo control method of a programmable logic controller, such as Figure 1 , including the steps of: The main control module identifies several axis control modules through the high-speed bus, assigns a unique identifier to each axis control module and binds the communication. The axis control module sends the hardware parameters to the main control module, and the main control module completes the communication initialization after verification; The main control module loads the standardized instruction library, receives the servo axis parameters input from the data interaction interface, generates an axis control program segment and sends it to the corresponding axis control module. The axis control module verifies the program segment and stores it, and feeds back an adaptation completion signal. The digital twin engine periodically collects data from the axis control module, drive, and encoder to build a virtual model. It compares the real-time data with the normal model. When the deviation coefficient exceeds a first threshold, the main control module marks the abnormal component and triggers an early warning. The main control module uploads the running parameters; when a fault occurs, the main control module extracts the characteristic parameters and matches them with the fault gene library. If the matching degree exceeds the second threshold, the fault type is determined, and a maintenance work order containing the fault location, component model, and operation steps is generated. Maintenance personnel issue module isolation instructions through the human-machine interface, and the main control module receives the instructions and isolates the target axis control module. After a new module is inserted, the main control module sends configuration parameters to complete synchronization, restores the bus connection, and records the running data.

[0019] In the implementation, the main control module identifies a plurality of axis control modules through a high-speed bus, assigns a unique identifier to each axis control module, and binds communication. Specifically, the main control module scans and identifies each connected axis control module through the back high-speed bus, obtains the inherent hardware identifier of each axis control module, assigns a unique identifier (such as "AX-01" to "AX-32") to each module according to the cascade order of the axis control module, and stores the unique identifier in association with the inherent hardware identifier of the module. The main control module and each axis control module establish a point-to-point communication link through the optical fiber communication interface of the axis control module, complete communication binding, and ensure that the main control module can send instructions to the corresponding axis control module and receive feedback information through the unique identifier.

[0020] In the implementation, the axis control module sends hardware parameters to the main control module, and the main control module verifies and completes communication initialization. Specifically, the axis control module transmits hardware parameters to the main control module through the back high-speed bus, including the signal type and voltage level of the I / O interface integrated therein, the maximum frequency and pulse equivalent of the pulse output channel, the communication protocol version of the optical fiber communication interface, and the model adaptation information of the corresponding servo driver and the protection threshold parameter of the built-in power management unit. After receiving the parameters, the main control module first checks whether the module model is within the cascade allowed range, then verifies whether the optical fiber communication interface parameters are consistent with the communication standard of the back high-speed bus, and simultaneously confirms the compatibility of the power management unit parameters with the system total power supply specifications. After verification, the main control module sends a synchronization instruction to the axis control module, which immediately starts the bidirectional verification of the optical fiber communication link, completes the negotiation of the data transmission encryption protocol and the alignment of the clock reference, and finally records the communication link state of the axis control module in the system registry to complete the initialization process.

[0021] In the implementation, the main control module loads a standardized instruction library, receives servo shaft parameters input by the data interaction interface, generates an axis control program segment, sends it to the corresponding axis control module, and stores it after verification by the axis control module. The axis control module feeds back an adaptation completion signal. Specifically, the main control module loads the built-in standardized control instruction library after power-on, which includes basic instructions such as axis start / stop and speed adjustment, as well as composite instructions such as multi-axis synchronization and interpolation linkage.

[0022] Specifically, the standardized control instruction library is stored in a modular data structure, the basic instructions include level trigger signal parameters of axis start / stop, PID parameter configuration interval of speed adjustment, encoder zeroing instruction format of position calibration, the composite instructions cover phase compensation algorithm parameters of multi-axis synchronization, and trajectory planning formula of interpolation linkage (such as pulse distribution ratio of linear interpolation, radius correction coefficient of circular interpolation). All instructions adopt a unified frame structure, including 8-bit operation code, 32-bit parameter field (containing unique identifier of axis control module) and 16-bit CRC check bit, ensuring that the axis control module can be quickly parsed when receiving through the fiber communication interface. The instruction library is dynamically bound with the hardware parameters of the axis control module, for example, the pulse output instruction will automatically match the maximum frequency of the corresponding module 2-way pulse channel (such as 500 kHz), avoiding exceeding the hardware threshold. For multi-axis coordination instructions, the library predefines signal association interfaces, which can directly call the linkage rules generated by dragging in the main control module logic editor (such as the start signal of axis AX-01 triggering the enable instruction of axis AX-02), without the need for additional code writing. The instruction library supports online updating, when technicians add new instruction templates through the data interaction interface, the system automatically checks the compatibility of the new instruction templates with existing hardware modules (such as checking whether the newly added gear synchronization instruction matches the electronic gear ratio parameters of the driver), and after updating, all axis control modules can synchronize to obtain the new instruction set through the high-speed bus, without affecting the current running program.

[0023] Technicians call the preset instruction templates through the graphical interface of the data interaction interface, input the axis number, transmission ratio, and limit parameters of the servo axis, and the data interaction interface automatically associates the hardware parameters (such as pulse output channel characteristics) of the corresponding axis control module to generate an independent axis control program segment. This process does not require modification of the main control module core program.

[0024] In the implementation, the digital twin engine periodically collects axis control module, driver, and encoder data to construct a virtual model. Specifically, the digital twin engine takes the main control module as the data aggregation core, realizes full-dimensional data acquisition through a three-layer acquisition link, and constructs a high-fidelity virtual mapping model based on hardware characteristics. The specific process is as follows: Axis control module data is collected in real time through the back high-speed bus, including the real-time state of the I / O interface, the real-time frequency and pulse count of the pulse output channel, the real-time delay and packet loss rate of the fiber communication interface, and the output voltage and module temperature of the built-in power management unit. Servo driver data is collected in real time through the fiber communication interface fixed by the axis control module, including the real-time output current, bus voltage, IGBT module temperature, running mode (position / speed / torque mode), and real-time alarm word of the driver. Encoder data is collected in real-time position value, speed value, acceleration, and signal integrity indicators (signal amplitude and noise ratio) of the absolute encoder in differential signal reception mode.

[0025] The synchronization strategy adopts the high-precision clock of the main control module as the reference, and realizes the time synchronization of the whole system through the IEEE1588 PTP protocol. The shaft control module, the driver and the encoder are all configured with hardware timestamp units, and the data acquisition automatically adds a time label to ensure the time synchronization of the three-way data. The acquisition cycle is fixed at 2ms, among which the shaft control module and the encoder data are collected by interrupt trigger, and the driver data is read by DMA direct memory access to avoid delay fluctuations caused by CPU intervention.

[0026] The raw data is first pre-processed locally by the shaft control module, and the pulse signal is de-jitter filtered, the current / voltage curve is peak suppressed, and the encoder position value is parity checked and jump detected. The pre-processed data is transmitted to the main control module through an encrypted channel, and finally hashed by the shaft control module unique identifier and timestamp, and stored in the ring buffer of the main control module.

[0027] The virtual model adopts a three-level architecture of "system-module-component". Specifically, the system-level model restores the physical layout of the entire control matrix in a three-dimensional scene, including the rail installation position (coordinate accuracy ±1mm) of the main control module and the shaft control module, the connection topology (visual signal flow) of the fiber and the bus, and the spatial distribution (associated with the mechanical structure of the actual production equipment, such as machine tool shaft system, mechanical arm joint) of the servo shaft. In the module-level model, each shaft control module corresponds to an independent virtual node, which real-time maps the waveform simulation of its pulse output (based on actual frequency to generate square wave / pulse string graphics), the state indicator light of I / O interface (green for normal, red for abnormal), and the energy flow simulation of power management unit (power distribution displayed with dynamic color scale). In the component-level model, the virtual entities of the driver and the encoder are subdivided, the driver model real-time simulates the IGBT switching state (based on current / voltage to calculate switching loss), and the encoder model reverses the dynamic characteristics of the mechanical transmission chain (including virtual compensation of gear clearance and screw pitch error) through position data.

[0028] In the implementation, the real-time data is compared with the normal model, and when the deviation coefficient exceeds the first threshold value, the main control module marks the abnormal component and triggers a warning. Specifically, the digital twin engine compares the pre-processed real-time data (including shaft control module pulse output waveform, driver current / voltage curve, and encoder position pulse string) with the normal condition model (reference model after system initialization calibration, including historical optimal operating parameter interval) in layers, which includes: The waveform parameters (such as pulse output waveform and current dynamic curve) use dynamic time warping (DTW) algorithm to calculate the similarity between real-time waveform and normal model waveform, and the quantitative index is waveform coincidence degree (range 0-100%), and the waveform deviation coefficient = 100%-coincidence degree; The absolute deviation percentage of the real-time value and the model predicted value of the numerical type parameter (such as the encoder position value, the driver voltage value) is calculated, and the numerical deviation coefficient = | (real-time value-predicted value) / predicted value | x 100%; The state matching degree algorithm is adopted for the state type parameter (such as the I / O interface level, the driver alarm word), the consistent bit number ratio of the real-time state and the normal model state is counted, and the state deviation coefficient = 100%-consistent bit number ratio.

[0029] The weight is set based on the influence degree of the parameter on the control accuracy, for example, the pulse output waveform (weight 30%), the encoder position feedback (weight 25%), the driver current value (weight 20%), the I / O interface state (weight 15%), and the communication link quality (weight 10%). Finally, the comprehensive deviation coefficient = Σ (single item deviation coefficient x corresponding weight).

[0030] For example, the preset first threshold in the technical solution is set to 5%, when the comprehensive deviation coefficient > 5%, the fault early warning is triggered. In addition, independent threshold strengthening judgment is set for key parameters, if the pulse waveform coincidence degree < 80% or the encoder position deviation > 0.1°, whether the comprehensive deviation meets the standard or not, the early warning is directly triggered to ensure that the abnormality of the core control link is not missed.

[0031] The precise positioning of the abnormality is realized in combination with the data source and the model level, specifically, if the pulse output waveform deviation dominates the comprehensive deviation (weight ratio > 50%), the pulse output channel of the corresponding shaft control module is positioned, and the optical fiber communication link is associated (because the communication abnormality may cause waveform distortion); If the driver current deviation > 8% and accompanied by IGBT temperature abnormality (exceeding the normal model 20℃), the servo driver and the associated motor are positioned (the current abnormality may be caused by the motor load abnormality); If the encoder position deviation > 0.05° and the speed curve fluctuation > 10%, the encoder and the mechanical transmission chain (such as gear, screw) are positioned (because the mechanical gap may cause the position feedback deviation); If multiple parameters deviate at the same time and are distributed in the jurisdiction range of the same shaft control module (such as the I / O, pulse, and communication parameters of the module are all out of standard), it is determined that the shaft control module is abnormal as a whole.

[0032] In the system-level view, the physical installation position of the abnormal axis control module is marked with a red flashing border, and its corresponding driver and encoder virtual model are associated with arrow lines; in the module-level view, the real-time curve of the abnormal parameter is displayed in enlarged scale and compared with the normal model curve (same time axis, red for real-time and green for normal), and the timestamps of key nodes such as pulse waveform distortion segment and current spike segment are marked; in the component-level view, the fault-associated components (such as driver IGBT module and encoder signal interface) are displayed in semi-transparent section, and specific abnormal parameter values (such as "current deviation 7.2%" and "position jump 0.08°") are marked.

[0033] In the implementation, the running parameters of the axis control module are uploaded; specifically, the axis control module uploads the running parameters through the optical fiber communication interface and the back high-speed bus double-channel parallelly to ensure the real-time and reliability of data transmission. For example, the uploaded parameters cover the full-dimensional state of the module itself and associated components, including the real-time level value and switching frequency of 8-way I / O interface, the current frequency, cumulative pulse number and waveform distortion rate of 2-way pulse output channel; the real-time delay, packet loss rate and encryption protocol state of optical fiber communication interface; the output voltage of built-in power management unit, module core temperature and protection threshold trigger state. At the same time, the real-time data of the 2 servo drives governed by the module are uploaded synchronously: output current, bus voltage, IGBT module temperature and 16-bit alarm status word; and the absolute position value (resolution 0.001°), real-time speed, acceleration and signal signal-to-noise ratio (dB value) of the corresponding encoder.

[0034] The uploading mechanism adopts "periodic + triggered" dual mode, for example, during normal operation, the parameters are uploaded at a fixed period of 10 ms, which is consistent with the sampling period of the dynamic load balancing of the main control module; when it is detected that the parameters exceed the normal range (such as pulse frequency jump > 10%, current exceeds rated value by 10%), interrupt uploading is triggered immediately, which has priority in occupying the communication bandwidth. The uploaded data are attached with 10 ns level timestamp based on IEEE1588 PTP protocol, encrypted by AES-128, and packaged into a unified frame structure (including 8-bit module ID, 24-bit parameter type identification, 128-bit data field and 16-bit CRC check code), through which the key control parameters (pulse, position type) are transmitted preferentially through the optical fiber interface, and the state type parameters (temperature, voltage type) are transmitted redundantly through the back high-speed bus. After being received by the main control module, the parameters are stored in the ring buffer according to the unique identification of the axis control module (supporting 24-hour data backtracking), and the feature parameters are extracted and pushed to the digital twin engine for model calibration, and real-time data basement is provided for the fault gene library. During the uploading process, the bus load is dynamically monitored, and when the bus occupancy rate > 5% due to the data volume of a single module, the transmission precision of non-critical parameters (such as temperature value with 1 decimal place) is automatically compressed to ensure that the control command transmission priority is not affected.

[0035] When the fault occurs, the main control module extracts the characteristic parameters and matches them with the fault gene library. Specifically, when the fault occurs, the main control module immediately calls the shaft control module to upload the real-time running parameters on the back high-speed bus through the optical fiber communication interface, and at the same time extracts the comprehensive deviation coefficient and key parameter deviation value generated by the digital twin engine, and integrates them to form a characteristic parameter set. These characteristic parameters cover multiple dimensions of control layer, drive layer, feedback layer, communication layer and energy layer, wherein the control layer includes the interrupt state of the pulse output channel (0 represents normal, 1 represents interruption), the program segment CRC check result (0 represents check failure, 1 represents success), and the instruction response delay time (unit: ms); the drive layer includes the 16-bit alarm status word of the servo driver (such as 0x000A indicating overload), the ratio of output current to rated current (percentage), and the difference between the real-time temperature of the IGBT module and the normal model temperature (unit: °C); the feedback layer includes the encoder position deviation value (unit: °), the speed curve fluctuation amplitude (percentage), and the signal signal-to-noise ratio (unit: dB); the communication layer includes the bit error rate of the optical fiber link (bit / s) and the bus collision frequency (times / 10ms); and the energy layer includes the power management unit output voltage ripple coefficient (percentage) and the module power consumption mutation rate (% / s).

[0036] The extracted characteristic parameters are standardized. Specifically, the Boolean type parameters are directly mapped to binary values of 0 or 1. For example, when the pulse output interrupt state is 1, it indicates interruption, and when it is 0, it indicates normal; when the program segment CRC check result is 1, it indicates that the check is passed, and when it is 0, it indicates that the check fails. The numerical type parameters are converted to standardized values in the 0-1 interval by a nonlinear normalization formula , where x is the independent variable, x' is the dependent variable, and k is the parameter weight coefficient, which is set according to the influence of the parameter on the control accuracy.

[0037] For example, the pulse output related parameter (instruction response delay) k = 0.8, and the temperature type parameter (IGBT temperature difference) k = 0.3. For example, when the instruction response delay is 5ms, the standardized value is 1-e (-0.8×5) = 0.9817, and when the current ratio is 120%, the standardized value is 1-e (-0.5×0.2) = 0.095. The enumerated type parameter is encoded with a single hot code, which decomposes the 16-bit driver alarm status word into 65536 binary bits. When it matches the typical alarm code (such as 0x000A for overload and 0x0010 for overvoltage) in the fault gene library, the corresponding bit is assigned a value of 1, and the remaining bits are assigned a value of 0. For example, when the real-time alarm code is 0x000A, the 10th bit (counting from 0) is set to 1, and the other bits are set to 0. Through the above processing, different types and different magnitudes of characteristic parameters are unified into standardized values that can be directly compared, ensuring that the matching calculation of the characteristic combination in the fault gene library can be accurately performed.

[0038] Specifically, the fault gene library is stored in a distributed database architecture, integrates historical fault handling records, equipment manufacturer maintenance manual data, and virtual fault cases generated by digital twin simulation, and forms a feature dataset covering common faults. Each fault entry contains feature parameter combinations, dynamic weight matrix, historical matching probability, fault evolution chain and associated component information. The feature parameter combinations strictly correspond to the standardized parameter values or intervals of the control layer, drive layer, feedback layer, communication layer and energy layer, for example, "pulse output interruption = 1, driver alarm word = 0x0000, fiber optic error rate > 1e-6" clearly points to the fiber joint loose fault; The dynamic weight matrix is adjusted in real time according to the recognition degree of the parameters to the fault, such as the weight of "current ratio > 150%" in motor stall fault is set to 0.4 (higher than other parameters), and the weight of "position deviation > 0.05°" in encoder fault is increased to 0.35; The historical matching probability is generated based on the statistics of nearly 3000 actual fault cases, and the initial value is taken from the manufacturer data, and the same type of fault is automatically updated every 100 times (the update formula is Pnew=0.7×Pold+0.3×this matching degree); The fault evolution chain records the secondary faults that may be caused if the fault is not timely handled, such as "driver overheating" may cause "IGBT module damage" if it lasts for 5 minutes, and the evolution probability (such as 68%) is marked; The associated component information includes the hardware model involved in the fault (such as "servo drive model SD-200A" and "encoder model EC-1024") and the mechanical associated components (such as "ball screw model SFU2005"). The gene library supports incremental updates, and after the system completes fault repair each time, new feature parameter combinations and processing results are automatically extracted, and after manual review, they are included in the library, and the weight matrix is optimized through random forest algorithm, so that the first matching degree of the newly added fault entry can reach more than 85%; For rare faults (occurrence frequency <0.1 times / year), combined with the fault injection simulation data of the digital twin engine, the features are supplemented to ensure complete coverage. In addition, each entry in the library is also associated with typical working condition labels (such as "high speed running stage" and "low load starting stage"), and when matching, the feature combinations under the same working condition are called first to improve the matching accuracy in complex scenarios.

[0039] For example, Table 1 below is a partial entry example table of the fault gene library: Fault type Characteristic parameter combination Parameter weight matrix (control layer, drive layer, feedback layer, communication layer, energy layer) Historical matching probability Associated components Optical fiber line fault Pulse output interrupt = 1, driver alarm word = 0x0000, position deviation < 0.05°, fiber bit error rate > 1e-6, voltage ripple < 5% [0.2,0.1,0.1,0.4,0.2] 93% Optical fiber joint, shaft control module optical fiber interface Motor stall Pulse output interruption = 0, current ratio = 160%, IGBT temperature difference = 25°C, speed fluctuation = 3%, power consumption mutation rate = 40% / s [0.1,0.4,0.2,0.1,0.2] 91% Servo motor, driver power module Encoder failure Pulse output normal, position deviation = 0.08°, speed fluctuation = 12%, signal-to-noise ratio = 28dB, bus conflict = 0 times / 10ms [0.1,0.1,0.5,0.2,0.1] 89% Encoder, mechanical transmission gear Shaft control module power failure Pulse output interruption = 1, program segment verification = 0, IGBT temperature difference = 0°C, bit error rate = 0, voltage ripple = 12% [0.3,0.1,0.1,0.1,0.4] 94% Power management unit, module power supply interface Table Partial entry example table of the fault gene library Specifically, the main control module compares the standardized feature parameters with the feature combinations of each fault entry in the gene library one by one, calculates the matching degree, and sets the feature parameter set as F={f1,f2,...,f n}, and the fault type as G, then the matching degree P(G|F) is:

[0040] P(G) is the prior probability of failure G (based on historical failure frequency, such as the proportion of pulse channel failure is 23%); P(f i |G) is the conditional probability of feature f i appearing when failure G occurs (taken from the statistical data of the gene library, such as the probability of pulse interruption when the pulse channel fails is 98%); W i is the weight corresponding coefficient, and ΣW i =1. n and i: for processing feature parameter dimension (n is the total number, and i is the index variable), m and k: for processing failure type dimension (m is the total number, and k is the index variable).

[0041] The matching degree formula calculates the most likely type of the current failure by integrating prior knowledge (historical failure frequency) and observation evidence (real-time feature parameters). Its essence is to compare the likelihood of observing the current features under different failure types, and thus find the most matching failure mode.

[0042] When the matching degree exceeds the second threshold value, the failure type is determined, and a maintenance work order containing the failure location, component model and operation steps is generated; the maintenance personnel issue module isolation instructions through the human-machine interface, specifically: when the matching degree calculation result exceeds the preset second threshold value (set to 90%), the main control module determines the failure type corresponding to the matching result as the final type of the current failure. Then start the maintenance work order generation process, extract the three-dimensional spatial coordinates of the failed component from the three-level virtual model of the digital twin engine, where the position of the axis control module is accurate to its installation slot number on the guide rail (such as "guide rail group B slot 5"), and is associated with its unique identifier (such as "AX-12"); the position of the servo driver is labeled on the specific layer coordinate of the equipment rack (such as "rack C layer 3 installation position"), and the encoder corresponds to the specific joint of the mechanical transmission chain (such as "mechanical arm elbow joint transmission gear box input end"), all coordinate data are matched with the physical installation position with an accuracy of ±1mm. The component model information is retrieved from the hardware parameter library of the main control module, including the model of the axis control module (such as "AXM-8002"), the model of the servo driver (such as "SD-300B"), the model of the encoder (such as "ENC-1024-ABZ"), and the detailed specifications of the required replacement parts (such as the fiber optic connector model "FC / PC-3.0", the power management unit output parameter "DC24V / 5A"), ensuring complete consistency with the system configuration. The operation steps are generated according to the time sequence logic of failure handling.

[0043] In the implementation, the main control module receives the instruction to isolate the target axis control module. Specifically, after the main control module receives the module isolation instruction issued by the maintenance personnel through the human-machine interface, it first verifies the legality of the instruction, verifies whether the unique identifier (such as "AX-12") of the target axis control module contained in the instruction is in the list of axis control modules registered in the current system, and checks the authority level of the maintenance personnel issuing the instruction (which requires a maintenance authority of level three or above). After the verification is passed, the isolation process is entered. The main control module sends a pre-isolation frame signal to the target axis control module through the back high-speed bus, which contains the isolation instruction code (0xAA), the timestamp, and the digital signature of the main control module. After receiving the signal, the target axis control module immediately suspends the current non-real-time control task (such as periodic state reporting), only retains the basic running monitoring function, and stores the current pulse count, driver state, and other key parameters to its non-volatile storage unit (EEPROM). After the storage is completed, it feeds back a "ready" signal to the main control module. The bus controller of the main control module immediately marks the bus address of the target axis control module as "isolated state", stops allocating communication bandwidth to this address, and closes the optical signal transceiver channel of the optical fiber communication interface to this module, cutting off the data interaction link at the hardware level. At this time, the load monitoring unit of the back high-speed bus confirms that the bus occupancy rate of the module has dropped to 0%. At the same time, the main control module sends a power-off instruction to the internal power management unit of the target axis control module. After receiving the instruction, the power management unit successively cuts off the power supply output to the peripheral servo driver, disconnects the connection with the system power supply, and only retains the minimum power supply for the module internal status indicator light (red isolation indicator light always on), and returns a "power-off" level signal to the main control module through the power feedback pin.

[0044] In the implementation, after the new module is inserted, the main control module sends configuration parameters to complete synchronization, restores the bus connection, and records running data. Specifically, when the new module is inserted into the installation slot along the guide rail, the contact sensor built-in the slot triggers the hardware detection interrupt of the main control module. The main control module immediately sends a module identification signal (containing a preset handshake code 0x5A5A) through the back high-speed bus. After receiving the signal, the new module returns its inherent hardware identifier (such as module serial number, factory calibration code) through the optical fiber communication interface. The main control module compares the identifier with the module type library allowed to access the system, confirms that it belongs to the axis control module type (such as AXM-8002 series) supporting cascading and is not listed in the fault blacklist, and then starts the identity verification process - uses the RSA public key stored in the main control module to encrypt and verify the hardware identifier sent by the new module. If the verification is passed, it is determined as a legal module.

[0045] Subsequently, the main control module retrieves the configuration parameter package bound to the unique identifier (such as "AX-12") of the shaft control module from the non-volatile storage unit, including the shaft control program segment (XML format encapsulated instruction sequence), the frequency threshold of the pulse output channel (500 kHz), the signal level standard of the I / O interface (DC 24V), the encryption protocol version of the fiber communication (AES-128), the model adaptation parameters of the associated servo driver (such as electronic gear ratio 1:10), and the initialization parameters of the digital twin model (such as three-dimensional coordinate offset). The parameter package is transmitted in a fragmented manner through the back high-speed bus, each piece of data is attached with a 32-bit CRC check code, and the new module receives and checks each piece of data. If the check is passed, it is stored in the local EEPROM, if not, it is requested to retransmit, and the whole transmission process is completed within 8 seconds, and the remaining 2 seconds are used for parameter loading and initialization.

[0046] After parameter synchronization is completed, the new module presses the calibration button to trigger a synchronization confirmation signal. After receiving the signal, the main control module first aligns the clock of the new module with the system reference clock through the IEEE1588 PTP protocol (time deviation controlled within 50 ns), then updates its bus address from "inactive" to "ready", and allocates 10% of the instantaneous bus bandwidth for initial data interaction. At the same time, the main control module sends a module state update instruction to the digital twin engine, which immediately activates the three-dimensional entity of the corresponding shaft control module in the virtual model, synchronously loads its hardware parameters and configuration program segment, and makes the pulse output waveform and I / O interface state of the virtual model real-time linked with the physical module.

[0047] When the bus connection is restored, the main control module first sends a test pulse sequence (100 kHz square wave, 200 ms duration) through the fiber communication interface, and the new module feeds back the pulse count result after receiving it. After confirming that the communication link is correct, the main control module includes it in the global control matrix and allows it to receive motion control instructions. At this time, the built-in power management unit of the new module automatically detects the input voltage (DC 24V ± 5%), and connects the external output power after confirming that it is normal, driving the associated servo driver to start. During this process, the bus communication and control instruction execution of other shaft control modules are not affected.

[0048] The system automatically records the full data of module replacement, including the insertion timestamp of the new module (accurate to microseconds), the verification result of parameter synchronization (such as CRC matching times, retransmission frame number), the first set of running parameters after initialization (pulse output initial frequency, driver no-load current, encoder zero position deviation), and the interval time length from the occurrence of the old module fault to the recovery of the new module. These data are stored in the history database of the main control module (supporting 180 days of backtracking) according to the unique identifier of the shaft control module, and are simultaneously synchronized to the fault gene library as feature samples of new cases, providing data support for the matching degree calculation of subsequent similar faults.

[0049] The application discloses a servo control system based on a programmable logic controller, which comprises: I. Hardware: Main control module: as the core of the system, it is connected with several axis control modules through the back high-speed bus, has the functions of identifying modules, distributing unique identification and binding communication, supports point-to-point optical fiber communication with the axis control module, can verify the hardware parameters of the axis control module and complete communication initialization.

[0050] Axis control module: solidifies integrated I / O interface, pulse output channel and optical fiber communication interface, each module independently corresponds to 2 servo drives, has a built-in power management unit, can transmit hardware parameters (such as pulse frequency, communication protocol version, etc.) to the main control module, and supports hot plug design.

[0051] High-speed communication link: including back high-speed bus (used for module identification and parameter transmission) and optical fiber communication interface (used for real-time instruction and data interaction), guarantees the real-time performance and reliability of multi-axis data transmission.

[0052] Sensing and execution components: including servo drives (collecting current, voltage and other data), absolute encoders (feeding back position and speed information) and environmental sensors, providing full-dimensional operation data for the system.

[0053] II. Software system: Standardized instruction library: built-in basic and composite instructions such as axis start / stop and multi-axis synchronization, adopts unified frame structure (including operation code, parameter field and check bit), can be dynamically bound with the hardware parameters of the axis control module, supports online updating and compatibility verification.

[0054] Digital twin engine: periodically acquires data through a three-layer acquisition link (axis control module, drive and encoder), constructs a three-level virtual model of “system-module-component”, compares with the normal working condition model to calculate the deviation coefficient, and can realize abnormal early warning and accurate positioning.

[0055] Fault intelligent diagnosis system: used for integrating fault gene library (including historical records, manufacturer data and virtual cases), extracting characteristic parameters (such as pulse state and current ratio) for standardized processing when a fault occurs, determining the fault type through matching degree calculation (combining prior probability and conditional probability), and generating a maintenance work order containing position, model and steps.

[0056] Dynamic load balancing module: used for real-time monitoring of bus load, when the load of a single module is too high, migrating non-real-time tasks to a light-load module to ensure the priority of control instructions.

[0057] An electronic device embodiment is also provided. The electronic device is in the form of a general purpose computing device. Components of the electronic device can include, but are not limited to, one or more processors or processing units, memory, a bus that connects the various components (including the memory and the processing unit(s)).

[0058] The bus represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration bus (e.g., AGP bus) and a Local bus using any of a variety of bus architectures (e.g., Industry Standard Architecture (ISA), Micro Channel Architecture (MCA), Enhanced ISA (EISA), Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus).

[0059] The electronic device typically includes a variety of computer device readable media. Such media can be any available media that is located either in the storage system or in another storage apparatus accessible by the electronic device.

[0060] The memory can include computer readable media in the form of volatile memory, such as random access memory (RAM) and / or cache memory. The electronic device can further include other removable / non-removable, volatile / non-volatile computer device storage media. By way of example only, storage system can be used for reading from and writing to a non-removable, non-volatile magnetic media (e.g., a "hard drive").

[0061] The electronic device can also be in communication with one or more external devices such as a keyboard or a pointing and / or selection device, either directly, through a hardwired connection, or wirelessly in communication with an appropriate wireless communication module and / or port. Additionally, an electronic device can communicate with one or more devices remotely located from the electronic device via the network adapter. In this regard, the network adapter enables the electronic device to communicate with or receive instructions from any of the other devices or systems coupled to the network. The processor executes the operating system and the various applications stored in the memory in conjunction with the bus and can also execute, for example, at least one step of a servo control method based on programmable logic controller provided by the embodiments of the present application, which at least one step includes: a digital twin engine periodically collects shaft control module, driver and encoder data, and constructs a virtual model; compares real-time data with a normal model, and when a deviation coefficient exceeds a first threshold value, a main control module marks an abnormal component and triggers a warning.

[0062] The present application also provides a computer readable storage medium having stored thereon a computer program, which, when executed by a processor, implements at least one step of a servo control method based on programmable logic controller provided by the embodiments of the present application, which at least one step includes: a digital twin engine periodically collects shaft control module, driver and encoder data, and constructs a virtual model; compares real-time data with a normal model, and when a deviation coefficient exceeds a first threshold value, a main control module marks an abnormal component and triggers a warning.

[0063] The computer storage medium of the embodiments of the present application can adopt any combination of one or more computer readable media. The computer readable medium can be a computer readable signal medium or a computer readable storage medium. The computer readable storage medium may, for example, be, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, system, or device, or any combination thereof. More specific examples (non-exhaustive list) of the computer readable storage medium include: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this document, the computer readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, system, or device.

[0064] A computer readable signal medium can include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal can take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium can be any computer readable medium that can be involved in

[0065] The computer readable program code embodied on a computer readable medium can be transmitted using any appropriate medium, including but not limited to wireless, wire line, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0066] Finally, it should be noted that the above-mentioned merely illustrates the preferred embodiments of the present application, but is not intended to limit the present application. Obviously, for those skilled in the present art, the various embodiments disclosed in the foregoing can be modified, or some technical features can be replaced equivalently, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0067] The above are the preferred embodiments of the present application, but not intended to limit the protection scope of the present application, therefore: any equivalent change made according to the structure, shape, principle of the present application shall be included in the protection scope of the present application.

Claims

1. A servo control method based on a programmable logic controller, characterized in that: Including steps: The main control module identifies several axis control modules through the high-speed bus, assigns a unique identifier to each axis control module and binds the communication. The axis control module sends the hardware parameters to the main control module, and the main control module completes the communication initialization after verification; The main control module loads the standardized instruction library, receives the servo axis parameters input from the data interaction interface, generates an axis control program segment and sends it to the corresponding axis control module. The axis control module verifies the program segment and stores it, and feeds back an adaptation completion signal. The digital twin engine periodically collects data from the axis control module, drive, and encoder to build a virtual model. It compares the real-time data with the normal model. When the deviation coefficient exceeds a first threshold, the main control module marks the abnormal component and triggers an early warning. The axis control module uploads operating parameters. When a fault occurs, the main control module extracts characteristic parameters and matches them with the fault gene library. If the matching degree exceeds the second threshold, the fault type is determined and a maintenance work order containing the fault location, component model, and operation steps is generated. Maintenance personnel issue module isolation commands through the human-machine interface. After receiving the commands, the main control module isolates the target axis control module. After the new module is inserted, the main control module sends the configuration parameters to complete the synchronization, restore the bus connection and record the operating data.

2. A servo control method based on a programmable logic controller according to claim 1, characterized in that: The main control module scans and identifies the connected axis control modules one by one through the high-speed bus on the back to obtain the inherent hardware identification of each axis control module; assigns a unique identification to each module according to the cascade order of the axis control modules, and stores the unique identification in association with the module's inherent hardware identification; establishes a point-to-point communication link between the main control module and each axis control module through the optical fiber communication interface of the axis control module to complete the communication binding, ensuring that the main control module can send instructions to the corresponding axis control module and receive feedback information through the unique identification.

3. The servo control method based on a programmable logic controller according to claim 1, characterized in that: The axis control module transmits hardware parameters to the main control module through the back high-speed bus, including the signal type and voltage level of its integrated I / O interface, the maximum frequency and pulse equivalent of the pulse output channel, the communication protocol version of the fiber optic communication interface, and the corresponding servo drive model adaptation information and the protection threshold parameters of the built-in power management unit. After receiving the parameters, the main control module first checks whether the module model is within the allowable cascade range, and then verifies whether the fiber optic communication interface parameters are consistent with the communication standard of the back high-speed bus. At the same time, it confirms the compatibility of the power management unit parameters with the system's total power supply specifications. After verification, the main control module sends a synchronization command to the axis control module, and the axis control module immediately starts the two-way verification of the fiber optic communication link, completes the negotiation of the data transmission encryption protocol and the alignment of the clock reference, and finally the main control module records the communication link status of the axis control module in the system registry to complete the initialization process.

4. The servo control method based on a programmable logic controller according to claim 1, characterized in that: After the main control module is powered on, it loads the built-in standardized control instruction library, which contains basic instructions for axis start / stop, speed regulation, and compound instructions for multi-axis synchronization and interpolation linkage. Specifically, the standardized control instruction library is stored in a modular data structure. The basic instructions include the level trigger signal parameters for axis start / stop, the PID parameter configuration interval for speed regulation, and the encoder clear instruction format for position calibration. The compound instructions include the phase compensation algorithm parameters for multi-axis synchronization and the trajectory planning formula for interpolation linkage.

5. The servo control method based on a programmable logic controller according to claim 1, characterized in that: The digital twin engine uses the main control module as the data aggregation core, acquires full-dimensional data through three-layer acquisition links, and builds a high-fidelity virtual mapping model based on hardware characteristics, as follows: The axis control module data is collected in real time through the high-speed bus on the back, including the real-time status of the I / O interface, the real-time frequency and pulse count of the pulse output channel, the real-time delay and packet loss rate of the optical fiber communication interface, and the output voltage and module temperature of the built-in power management unit. Servo drive data is collected synchronously through the optical fiber communication interface solidified by the axis control module, including the real-time output current, bus voltage, IGBT module temperature, operating mode and real-time alarm word of the drive; Encoder data, using differential signal reception to collect the real-time position value, speed value, acceleration and signal integrity index of the absolute encoder; The high-precision clock of the main control module is used as the benchmark, and the IEEE1588PTP protocol is used to achieve time synchronization for the entire system. The axis control module, drive, and encoder are all equipped with hardware time stamp units, which automatically add time tags during data collection to ensure time synchronization of the three channels of data. The raw data is first pre-processed locally by the axis control module, with anti-jitter filtering performed on the pulse signal, spike suppression performed on the current / voltage curve, and parity check and jump detection performed on the encoder position value; The preprocessed data is transmitted to the main control module through an encrypted channel, and finally hashed and divided according to the unique identifier and timestamp of the axis control module, and stored in the ring buffer of the main control module.

6. A servo control method based on a programmable logic controller according to claim 1, characterized in that: The virtual model adopts a three-level architecture of system, module, and component. Specifically, the system-level model restores the physical layout of the entire control matrix in a three-dimensional scene, including the guide rail installation position of the main control module and the axis control module, the connection topology of the optical fiber and the bus, and the spatial distribution of the servo axis; in the module-level model, each axis control module corresponds to an independent virtual node, and its pulse output waveform simulation, I / O interface status indicator light, and power management unit energy flow simulation are mapped in real time; in the component-level model, the virtual entities of the driver and encoder are subdivided, the driver model simulates the IGBT switching state in real time, and the encoder model inverts the dynamic characteristics of the mechanical transmission chain through position data.

7. The servo control method based on a programmable logic controller according to claim 1, characterized in that: Comparing the real-time data with the normal model includes: the digital twin engine compares the pre-processed real-time data with the normal operating condition model in layers, and calculates the weighted sum of the deviation coefficients of different parameters as the final comprehensive deviation coefficient.

8. The servo control method based on a programmable logic controller according to claim 1, characterized in that: The axis control module uploads the operating parameters including: the axis control module uploads the operating parameters in parallel via the optical fiber communication interface and the back high-speed bus dual channels, and the upload adopts the "cycle + trigger" dual mode.

9. The servo control method based on a programmable logic controller according to claim 1, characterized in that: The main control module extracts characteristic parameters and matches them with the fault gene library, including: when a fault occurs, the main control module immediately retrieves the real-time operating parameters uploaded by the axis control module through the optical fiber communication interface and the back high-speed bus, and simultaneously extracts the comprehensive deviation coefficient and key parameter deviation value generated by the digital twin engine, integrating them to form a characteristic parameter set; the extracted characteristic parameters are standardized so that characteristic parameters of different types and magnitudes are unified into standardized values ​​that can be directly compared, ensuring that matching calculations with characteristic combinations in the fault gene library can be performed; The fault gene library is stored in a distributed database architecture, integrating historical fault handling records, equipment manufacturer maintenance manual data and virtual fault cases generated by digital twin simulation to form a feature data set covering common faults; each fault entry contains a feature parameter combination, a dynamic weight matrix, a historical matching probability, a fault evolution chain and associated component information. The main control module compares the standardized feature parameters with the feature combination of each fault entry in the gene library one by one to calculate the matching degree.

10. The servo control method based on a programmable logic controller according to claim 9, characterized in that: When the matching calculation result exceeds the preset second threshold, the main control module immediately determines the fault type corresponding to the matching result as the final type of the current fault; then the maintenance work order generation process is started, and the three-dimensional spatial coordinates of the faulty component are extracted from the three-level virtual model of the digital twin engine. The position of the axis control module is accurate to its installation slot number on the guide rail and is associated with its unique identifier; the position of the servo drive is marked on the specific shelf coordinates of the equipment rack, and the encoder corresponds to the specific joint point of the mechanical transmission chain; the component model information is retrieved from the hardware parameter library of the main control module, and the operation steps are generated according to the timing logic of fault handling.

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