A machine tool repeated positioning control system

Abstract

The present invention discloses a machine tool repetitive positioning control system, which relates to the field of machine tool control technology. The system summarizes the data of all stations in real time through a comprehensive evaluation and correction module, conducts a comprehensive analysis of the multi-station processing conditions, and outputs a processing accuracy index Q. At the same time, the system compares and evaluates the processing accuracy index Q with a preset accuracy threshold Qth. If it is found that the comprehensive error exceeds the allowable range, an iterative control process is executed. The process combines dynamic adjustment of control parameters, compensation mechanisms, and evaluation and optimization measures to gradually reduce the errors caused by position, speed, and temperature until the processing accuracy index Q ≤ the accuracy threshold Qth. This iterative evaluation and correction mechanism ensures that the system can continuously optimize the processing quality and meet the strict requirements of the high-end manufacturing field for accuracy and consistency, while effectively reducing production losses and costs and improving product yields.

Description

Technical Field

[0001] The invention relates to the technical field of machine tool control, in particular to a machine tool repeated positioning control system. Background Art

[0002] The machine tool repetitive positioning control system belongs to the field of intelligent manufacturing and automatic control, and is an important part of modern industrial automation. In this field, CNC machine tools are widely used in mechanical processing, automobile parts manufacturing, and aerospace industries due to their high precision and high efficiency. As the manufacturing industry continues to increase its requirements for processing quality and production efficiency, traditional machine tool positioning and processing technologies are gradually developing towards high-precision multi-station processing control. In the multi-station grinding precision optimization scenario, the repetitive positioning accuracy of the machine tool directly affects the consistency and product quality of the synchronous processing of multiple workpieces, and has become one of the key technical problems in high-end precision manufacturing.

[0003] At present, servo control systems in multi-station processing scenarios face many challenges in actual operation, such as differences in workpiece processing accuracy due to position deviation, speed fluctuation or ambient temperature changes. These problems are particularly prominent in high-precision grinding scenarios. Existing systems usually rely on simple single-shot error feedback control and cannot achieve dynamic prediction and compensation of multi-station errors. In addition, during the workpiece processing process, since multiple factors such as position, speed and ambient temperature cannot be fully and real-time considered, the system is prone to error accumulation and even processing failure when facing dynamic conditions such as load changes or thermal expansion. These shortcomings limit processing efficiency and consistency of product quality. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a machine tool repeated positioning control system, which solves the problems mentioned in the background technology.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: a machine tool repeated positioning control system, including a cutting data acquisition module, a data processing module, a servo motor synchronous control module, a dynamic prediction and compensation module and a comprehensive evaluation and correction module;

[0006] The cutting data acquisition module collects machine tool data in real time by installing a sensor group on the cutting machine tool, and constructs a central control system to transmit the machine tool data to the central control system;

[0007] The data processing module receives machine tool data in real time in the central control system, pre-processes the machine tool data, obtains a standard data group, performs calculation processing on the standard data group to obtain cutting processing data, and constructs a time series database, and stores the standard data group and the cutting processing data in the time series database;

[0008] The servo motor synchronous control module calculates the servo motor position adjustment value △P of each station based on the cutting processing data and writes a positioning control program through PLC i At the same time, the servo motor speed adjustment value S of each station is calculated and output based on the speed adjustment algorithm i , adjust the servo motor position by △P i And the servo motor speed adjustment S i , synchronously adjust the position and speed of the servo motor;

[0009] The dynamic prediction and compensation module extracts historical cutting processing data to predict and calculate the future position error value E Epi (t+△t), and preset the error threshold E and the future position error value E Epi (t+△t) performs error evaluation. If the error evaluation shows an abnormal error, the compensation mechanism is executed;

[0010] The comprehensive evaluation and correction module constructs a comprehensive processing algorithm formula to calculate and output the comprehensive processing accuracy index Q of each workstation, and performs a secondary comparative evaluation on the preset accuracy threshold Qth and the comprehensive processing accuracy index Q. If the position adjustment is evaluated to be abnormal, the iterative control process is executed.

[0011] Preferably, the cutting data acquisition module includes a data acquisition unit and a data transmission unit;

[0012] The data acquisition unit collects machine tool data in real time by installing a sensor group on the cutting machine tool;

[0013] The sensor group includes a photoelectric encoder, a speed environment control module, a force sensor and an infrared temperature sensor;

[0014] The machine tool data includes the real-time position Pi of the servo motor at the i-th station, the real-time speed Si of the servo motor at the i-th station, the grinding force Fi at the i-th station, and the cutting area temperature Ti at the i-th station;

[0015] The data transmission unit transmits the machine tool data collected in real time to the central control system by constructing the central control system;

[0016] The specific transmission method is as follows;

[0017] Use the industrial bus protocol CAN to transmit the real-time position Pi and real-time speed Si of the servo motor at the i-th station to the central control system;

[0018] At the same time, the communication modules of the force sensor and infrared temperature sensor are used to transmit the collected grinding force Fi of the i-th station and the cutting area temperature Ti of the i-th station to the central control system through the Modbus communication protocol.

[0019] Preferably, the data processing module includes a preprocessing unit, a calculation processing unit and a data storage unit;

[0020] The preprocessing unit receives the machine tool data in real time in the central control system, performs data cleaning and normalization on the machine tool data, and marks the machine tool data with a timestamp to obtain a standard data set;

[0021] The standard data set includes the real-time position Pi(t) of the servo motor at the i-th station at time t, the real-time speed Si(t) of the servo motor at the i-th station at time t, the grinding force Fi(t) at the i-th station at time t, and the cutting area temperature Ti(t) at the i-th station at time t;

[0022] The calculation processing unit performs calculation processing based on the standard data group to obtain cutting processing data;

[0023] The cutting processing data includes the position deviation Epi(t) of the i-th station at time t and the grinding force deviation Efi(t) of the grinding tool at the i-th station at time t;

[0024] The workstation position deviation Epi (t) and grinding force deviation Efi (t) are outputted by the following calculation formulas:

[0025] ;

[0026] ;

[0027] In the formula, n represents the total number of workstation positions, and Fm represents the target cutting force;

[0028] The data storage unit constructs a time series database and sets a write port, a write port, a real-time data table and a historical data table. The standard data group and the cutting processing data acquired in real time are stored in the real-time data table through the write port, and the standard data group and the cutting processing data originally in the real-time data table are automatically transferred to the historical data table and sorted in the order of timestamps.

[0029] Preferably, the servo motor synchronous control module includes a speed synchronization adjustment unit and a synchronous positioning unit;

[0030] The speed synchronization adjustment unit extracts the grinding force deviation Efi(t) of the grinding tool at the i-th station at time t through the write port, calculates and outputs the servo motor speed adjustment value S i ;

[0031] The servo motor speed adjustment amount S i The output is calculated by the following algorithm formula;

[0032] ;

[0033] In the formula, S i (t) represents the speed adjustment of the servo motor at the i-th station at time t, and Sm represents the target speed adjustment of the servo motor.

[0034] Preferably, the synchronous positioning unit is based on the obtained speed adjustment value S of the servo motor at the i-th station at time t. i (t), write the positioning control program through PLC, calculate and obtain the servo motor position adjustment value △P of each station i , dynamically balance the errors of position and velocity;

[0035] The servo motor position adjustment amount △P i The output is calculated by the following algorithm formula;

[0036] ;

[0037] In the formula, Kp l Represents the first compensation gain control coefficient, Kv l Indicates the speed control coefficient, Kc l represents the integral control coefficient, dt represents the time integral variable, △P i (t) represents the servo motor position adjustment amount at time t.

[0038] Preferably, the dynamic prediction and compensation module includes an error prediction unit, a prediction evaluation unit and an error compensation unit;

[0039] The error prediction unit extracts the position deviation Epi(t) of the i-th station at time t in the historical data table through the write port after adjusting the servo motor position and the servo motor speed, and predicts the position error value E at time t+△t. Ep，i (t+△t);

[0040] The position error value E at time t+Δt Epi (t+△t) is calculated by the following algorithm formula;

[0041] ;

[0042] In the formula, represents the first-order derivative of the error, It represents the second derivative of the error, the acceleration of the error change, and △t represents the predicted time step.

[0043] Preferably, the prediction evaluation unit sets an error threshold E based on the user, and then compares it with the predicted position error value E at the time t+Δt. Epi (t+△t) to evaluate the error and analyze the cutting accuracy. The specific evaluation contents are as follows;

[0044] At time t+△t, the position error value is E Epi When (t+△t)≤error threshold E, it means that the predicted cutting accuracy is abnormal, and the compensation mechanism is executed at this time;

[0045] At time t+△t, the position error value is E Epi When (t+△t)>error threshold E, it means that the predicted cutting accuracy is normal. At this time, the current control state is maintained without additional compensation.

[0046] Preferably, the error compensation unit executes a compensation mechanism when the predicted cutting accuracy is abnormal. The compensation mechanism calculates and outputs the servo motor position compensation value ΔPb of the ith station at time t by introducing a temperature compensation factor AT. i (t); when the servo motor position compensation amount △Pb i (t) is sent to the servo motor to correct the position in advance;

[0047] The servo motor position compensation △Pb i (t) Calculate the output using the following algorithm formula;

[0048] ;

[0049] Wherein, Kp2 represents the second compensation gain control coefficient.

[0050] Preferably, the comprehensive assessment correction module includes a data aggregation unit and a comprehensive assessment unit;

[0051] After the data aggregation unit has completed the execution through the re-compensation mechanism, the error scores of all workstations are summed up to obtain the comprehensive machining accuracy index Q to quantify the machining quality;

[0052] The comprehensive machining accuracy index Q is calculated and output by the following algorithm formula:

[0053] ;

[0054] Preferably, the comprehensive evaluation unit presets the accuracy threshold Qth according to the processing requirements by the user, and then performs a preliminary comparative evaluation with the comprehensive processing accuracy index Q to analyze the overall error of the cutting process. The specific evaluation contents are as follows;

[0055] When the comprehensive machining accuracy index Q> the accuracy threshold Qth, it means that the comprehensive error is abnormal, and the iterative control process is executed until the comprehensive error is normal and the iteration is stopped;

[0056] When the comprehensive machining accuracy index Q ≤ the accuracy threshold Qth, it means that the comprehensive error is normal and no further adjustment is required.

[0057] The present invention provides a machine tool repetitive positioning control system, which has the following beneficial effects:

[0058] (1) The system collects and processes key parameters such as the position, speed, grinding force and cutting temperature of multi-station servo motors in real time through the cooperation of the cutting data acquisition module and the data processing module, and establishes a central control system to manage the data in a unified manner. The servo motor synchronous control module calculates and synchronously adjusts the servo motor position adjustment value △P of each station based on the acquired cutting processing data, combined with the positioning adjustment and speed adjustment algorithms. i and speed adjustment S i This mechanism greatly improves the synchronization and consistency of multi-station processing, significantly reduces the impact of position and speed deviations on processing quality, and thus achieves high-precision and high-efficiency automated processing.

[0059] (2) The dynamic prediction and compensation module of the system extracts historical cutting data and calculates the future position error value E in real time. Epi (t+△t), building a dynamic error prediction and compensation mechanism. When the predicted future error exceeds the preset threshold E, the system automatically executes the compensation mechanism and outputs the servo motor position compensation △Pb through the temperature compensation factor AT and the compensation gain coefficient Kp2. i (t), and correct the servo motor position in advance. This modular compensation design effectively overcomes the processing errors caused by thermal expansion, load changes or dynamic interference during the processing, enhances the system's adaptability to complex working conditions, and makes the workpiece processing quality more stable.

[0060] (3) The system uses a comprehensive evaluation and correction module to summarize the data of all workstations in real time, conduct a comprehensive analysis of the multi-workstation processing situation, and output the processing accuracy index Q. At the same time, the system compares and evaluates the processing accuracy index Q with the preset accuracy threshold Qth. If it is found that the comprehensive error exceeds the allowable range, the iterative control process is executed. This process combines dynamic adjustment of control parameters, compensation mechanisms and evaluation and optimization measures to gradually reduce the errors caused by position, speed and temperature until the processing accuracy index Q≤Qth. This iterative evaluation and correction mechanism ensures that the system can continuously optimize the processing quality and meet the strict requirements of high-end manufacturing for accuracy and consistency, while effectively reducing production losses and costs and improving product yields. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 The present invention is a schematic flow chart of a machine tool repeated positioning control system. DETAILED DESCRIPTION

[0062] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0063] Example 1

[0064] See also Figure 1 , the present invention provides a machine tool repeated positioning control system, including a cutting data acquisition module, a data processing module, a servo motor synchronous control module, a dynamic prediction and compensation module and a comprehensive evaluation and correction module;

[0065] The cutting data acquisition module collects machine tool data in real time by installing a sensor group on the cutting machine tool, and builds a central control system to transmit the machine tool data to the central control system;

[0066] The data processing module receives machine tool data in real time in the central control system, pre-processes the machine tool data, obtains a standard data group, performs calculation processing on the standard data group to obtain cutting processing data, and builds a time series database, and stores the standard data group and cutting processing data in the time series database;

[0067] The servo motor synchronous control module is based on the cutting processing data, and the positioning control program is written through the PLC to calculate the servo motor position adjustment value △P for each station. i At the same time, the servo motor speed adjustment value S of each station is calculated and output based on the speed adjustment algorithm i , adjust the servo motor position by △P i And the servo motor speed adjustment S i , synchronously adjust the position and speed of the servo motor;

[0068] The dynamic prediction and compensation module extracts historical cutting data to predict and calculate the future position error value E. Epi (t+△t), and preset the error threshold E and the future position error value E Epi (t+△t) performs error evaluation. If the error evaluation shows an abnormal error, the compensation mechanism is executed;

[0069] The comprehensive evaluation and correction module constructs a comprehensive processing algorithm formula to calculate and output the comprehensive processing accuracy index Q of each workstation, and performs a secondary comparative evaluation on the preset accuracy threshold Qth and the comprehensive processing accuracy index Q. If the position adjustment is evaluated to be abnormal, the iterative control process is executed.

[0070] In this embodiment, the cutting data acquisition module of the system collects key machine tool data including servo motor position Pi, rotation speed Si, grinding force Fi and cutting area temperature Ti in real time by installing a sensor group on the cutting machine tool, and transmits it to the central control system through the CAN bus and Modbus protocol, providing real-time and accurate basic information for subsequent data processing and control decisions; the data processing module cleans and normalizes the received raw machine tool data, constructs a standard data group, and combines the calculation unit to obtain the position deviation Epi (t) of the i-th station at time t and the grinding force deviation Efi (t) of the i-th station grinding tool at time t, and constructs a basic data environment for dynamic tracking and prediction through real-time storage and historical transfer of the time series database. The servo motor synchronous control module calculates and outputs the servo motor position adjustment value △P based on the processing data through the positioning control program written by the PLC. i and speed adjustment S i , ensuring the synchronization of servo motor movements at all workstations. The dynamic prediction and compensation module uses historical data to calculate the future position error Epi (t), and evaluates the prediction accuracy based on the error threshold E. When the error is abnormal, the compensation mechanism is automatically executed to correct the servo motor position in advance and reduce the dynamic error. The comprehensive evaluation and correction module constructs the processing accuracy index Q, compares and evaluates it with the accuracy threshold Qth, and conducts quantitative analysis and iterative optimization of multi-station processing to ensure that the overall processing quality meets the standard. Compared with the traditional single error feedback control system, this system introduces a new multi-dimensional data analysis, dynamic prediction compensation and comprehensive evaluation mechanism in multi-station processing, which significantly improves the error response speed and control accuracy. It can not only quickly correct real-time errors, but also achieve active control by predicting potential anomalies in advance, especially showing stronger robustness when facing complex processing conditions (such as load fluctuations or thermal expansion).

[0071] Example 2

[0072] This embodiment is explained in Example 1, please refer to Figure 1 ,Specifically: the cutting data acquisition module includes a data acquisition unit and a data transmission unit;

[0073] The data acquisition unit collects machine tool data in real time by installing a sensor group on the cutting machine tool;

[0074] The sensor group includes a photoelectric encoder, a speed and environmental control module, a force sensor and an infrared temperature sensor;

[0075] The machine tool data includes the real-time position Pi of the servo motor at the i-th station, the real-time speed Si of the servo motor at the i-th station, the grinding force Fi at the i-th station, and the cutting area temperature Ti at the i-th station;

[0076] The real-time position Pi of the servo motor at the i-th station is obtained by installing a photoelectric encoder on the shaft end of the servo motor of the cutting machine at the i-th station. The photoelectric encoder converts the rotation angle of the motor into a digital signal, which is processed by the servo controller to generate a corresponding numerical position feedback.

[0077] The real-time speed Si of the servo motor at the i-th station is obtained through the speed environmental control module of the servo motor of the cutting machine tool at the i-th station;

[0078] The grinding force Fi at the i-th station is obtained by real-time measurement using a force sensor installed on the workpiece grinding tool;

[0079] The cutting area temperature Ti of the i-th station is obtained by detecting the temperature change of the cutting area of ​​the grinding area through an infrared temperature sensor;

[0080] The data transmission unit transmits the real-time collected machine tool data to the central control system by building a central control system;

[0081] The specific transmission method is as follows;

[0082] Use the industrial bus protocol CAN to transmit the real-time position Pi and real-time speed Si of the servo motor at the i-th station to the central control system;

[0083] At the same time, the communication modules of the force sensor and infrared temperature sensor are used to transmit the collected grinding force Fi of the i-th station and the cutting area temperature Ti of the i-th station to the central control system through the Modbus communication protocol.

[0084] In this embodiment, the system realizes the real-time acquisition and efficient transmission of key processing parameters of multiple stations of the machine tool through the organic combination of the data acquisition unit and the data transmission unit of the cutting data acquisition module. The photoelectric encoder, speed environmental control module, force sensor and infrared temperature sensor installed in the data acquisition unit can fully cover the core parameters such as the real-time position Pi of the servo motor of the i-th station, the real-time speed Si of the servo motor of the i-th station, the grinding force Fi of the i-th station and the cutting area temperature Ti of the i-th station, and ensure the high precision and multi-dimensionality of the data. The data transmission unit quickly transmits the collected data to the central control system through the CAN bus protocol and the Modbus communication protocol, providing accurate and real-time basic information for subsequent data processing and control. Compared with traditional technical means based on single parameters or interval sampling, this module realizes the multi-dimensional, real-time and precise data acquisition, makes up for the problems of information lag and one-sided data, and provides a reliable basis for dynamic adjustment during the processing process. At the same time, through the integrated industrial communication protocol design, the data transmission delay is reduced, ensuring that the system response speed is significantly improved.

[0085] Example 3

[0086] This embodiment is explained in Example 1, please refer to Figure 1 ,Specifically: the data processing module includes a pre-processing unit, a computing processing unit and a data storage unit;

[0087] The preprocessing unit receives the machine tool data in real time from the central control system, performs data cleaning and normalization on the machine tool data, and marks the machine tool data with a timestamp to obtain a standard data set;

[0088] The standard data set includes the real-time position Pi(t) of the servo motor at the i-th station at time t, the real-time speed Si(t) of the servo motor at the i-th station at time t, the grinding force Fi(t) at the i-th station at time t, and the cutting area temperature Ti(t) at the i-th station at time t;

[0089] The calculation processing unit performs calculation processing based on the standard data group to obtain cutting processing data;

[0090] The cutting processing data include the position deviation Epi(t) of the i-th station at time t and the grinding force deviation Efi(t) of the grinding tool at the i-th station at time t;

[0091] The workstation position deviation Epi (t) and grinding force deviation Efi (t) are output by the following calculation formulas:

[0092] ;

[0093] ;

[0094] In the formula, n represents the total number of workstation positions, and Fm represents the target cutting force;

[0095] The data storage unit constructs a time series database and sets a write port, a write port, a real-time data table and a historical data table. The standard data group and cutting processing data acquired in real time are stored in the real-time data table through the write port, and the original standard data group and cutting processing data in the real-time data table are automatically transferred to the historical data table and sorted in timestamp order.

[0096] In this embodiment, the data processing module of the system realizes efficient processing and precise management of cutting data through the collaboration of the preprocessing unit, the computing unit and the data storage unit. The preprocessing unit cleans and normalizes the real-time collected machine tool data, eliminates noise and deviation, generates a standardized time series data group, and marks a timestamp for each data group to ensure data consistency and traceability. Based on the standard data group, the computing unit further calculates the position deviation Epi (t) of the i-th station at time t and the grinding force deviation Efi (t) of the i-th station grinding tool at time t, providing key quantitative indicators for error evaluation and control in the processing process. The data storage unit realizes the dynamic storage and management of real-time data and historical data by constructing a time series database, so that the system can quickly call real-time data for control decisions, and use historical data for trend analysis and prediction. This module significantly improves the data processing efficiency and accuracy through full-process automated processing. The establishment of a standardized data group ensures the uniformity of multi-station processing parameters, and the introduction of a time series database provides stable support for the tracking and prediction calculation of historical data. These improvements not only shorten the data processing cycle, but also significantly increase the system's response speed to dynamic machining processes.

[0097] Example 4

[0098] This embodiment is explained in Example 1, please refer to Figure 1 ,Specifically: the servo motor synchronous control module includes a speed synchronous adjustment unit and a synchronous positioning unit;

[0099] The speed synchronization adjustment unit extracts the grinding force deviation Efi(t) of the grinding tool at the i-th station at time t through the write port, calculates and outputs the servo motor speed adjustment S i ;

[0100] Servo motor speed adjustment S i The output is calculated by the following algorithm formula;

[0101] ;

[0102] In the formula, S i(t) represents the speed adjustment of the servo motor at the i-th station at time t, and Sm represents the target speed adjustment of the servo motor.

[0103] The synchronous positioning unit adjusts the servo motor speed S of the i-th station based on the acquired time t i (t), write the positioning control program through PLC, calculate and obtain the servo motor position adjustment value △P of each station i , dynamically balance the errors of position and speed, ensure the synchronization of all servo motors and improve the consistency of workpiece processing;

[0104] Servo motor position adjustment △P i The output is calculated by the following algorithm formula;

[0105] ;

[0106] In the formula, Kp l Represents the first compensation gain control coefficient, Kv l Indicates the speed control coefficient, Kc l represents the integral control coefficient, dt represents the time integral variable, △P i (t) represents the servo motor position adjustment amount at time t.

[0107] In this embodiment, the servo motor synchronous control module of the system realizes the precise synchronous adjustment of the position and speed of the multi-station servo motor through the coordinated work of the speed synchronization adjustment unit and the synchronous positioning unit. The speed synchronization adjustment unit dynamically calculates the servo motor speed adjustment amount S based on the grinding force deviation Efi (t) of the grinding tool at the i-th station at time t extracted in real time. i (t) to ensure that the motor speed of each station is consistent with the target requirements. The synchronous positioning unit further uses the speed adjustment of the servo motor to write a positioning control program through the PLC to calculate the servo motor position adjustment △P i (t), and integrates speed, position and historical accumulated errors at the same time, and achieves dynamic error balance through control coefficients such as Kp1, Kv1, and Kc1 to ensure high synchronization of all station actions. Compared with the traditional single-dimensional control method, this module significantly improves control accuracy and response speed through dual dynamic adjustment of speed and position, as well as multivariable closed-loop control of servo motors. The introduction of the position adjustment formula not only effectively balances the dynamic errors in multi-station processing, but also optimizes the robustness of the system and avoids processing inconsistencies caused by error accumulation.

[0108] Example 5

[0109] This embodiment is explained in Example 4. Please refer to Figure 1 ,Specifically: the dynamic prediction and compensation module includes an error prediction unit, a ,prediction evaluation unit and an error compensation unit;

[0110] The error prediction unit extracts the position deviation Epi(t) of the i-th station at time t from the historical data table through the write port after adjusting the servo motor position and servo motor speed, and predicts the position error value E at time t+△t. Ep，i (t+△t);

[0111] Position error value E at time t+△t Epi (t+△t) is calculated by the following algorithm formula;

[0112] ;

[0113] In the formula, represents the first derivative of the error, the speed at which the error changes, It represents the second derivative of the error, the acceleration of the error change, and △t represents the predicted time step.

[0114] The prediction evaluation unit sets the error threshold E based on the user, and then compares it with the predicted position error value E at the time t+△t. Epi (t+△t) to evaluate the error and analyze the cutting accuracy. The specific evaluation contents are as follows;

[0115] At time t+△t, the position error value is E Epi When (t+△t)≤error threshold E, it means that the predicted cutting accuracy is abnormal, and the compensation mechanism is executed at this time;

[0116] At time t+△t, the position error value is E Epi When (t+△t)>error threshold E, it means that the predicted cutting accuracy is normal. At this time, the current control state is maintained without additional compensation.

[0117] The error compensation unit executes the compensation mechanism when the predicted cutting accuracy is abnormal. The compensation mechanism calculates and outputs the servo motor position compensation value △Pb of the ith station at time t by introducing the temperature compensation factor AT. i (t); when the servo motor position compensation amount △Pb i (t) is sent to the servo motor to correct the position in advance;

[0118] Servo motor position compensation △Pb i (t) Calculate the output using the following algorithm formula;

[0119] ;

[0120] Wherein, Kp2 represents the second compensation gain control coefficient.

[0121] In this embodiment, the system realizes early error evaluation and dynamic correction in multi-station processing through the synergy of the error prediction unit, the prediction evaluation unit and the error compensation unit through the dynamic prediction and compensation module. The error prediction unit is based on the historical position deviation Epi (t) data, and calculates and predicts the position error E at the future time t+Δt through the first-order derivative of the position error, the velocity and the second-order derivative, and the acceleration. Epi (t+△t). The prediction evaluation unit evaluates the predicted error value and the set threshold E to accurately determine whether the cutting accuracy is abnormal, and triggers the compensation mechanism when the error exceeds the threshold. The error compensation unit introduces the temperature compensation factor AT, combined with the compensation gain coefficient Kp2, to dynamically calculate the servo motor position compensation ΔPb i (t), and adjust the position of the servo motor in advance to effectively eliminate processing anomalies. Compared with the traditional passive error feedback control method, this module innovatively realizes active control and advance correction by introducing error prediction and dynamic compensation, which not only reduces the processing quality problems caused by error accumulation, but also significantly improves the system's adaptability to dynamic interference such as load fluctuations or thermal expansion. The addition of temperature compensation factors further enhances the system's processing stability under complex working conditions.

[0122] Example 6

[0123] This embodiment is explained in Example 5. Please refer to Figure 1 ,Specifically: the comprehensive evaluation and correction module includes a data ,aggregation unit and a comprehensive evaluation unit;

[0124] After the data aggregation unit is executed through the re-compensation mechanism, the error scores of all workstations are summed up to obtain the comprehensive machining accuracy index Q to quantify the machining quality;

[0125] The comprehensive machining accuracy index Q is calculated and output by the following algorithm formula;

[0126] ;

[0127] The comprehensive evaluation unit uses the user to preset the accuracy threshold Qth according to the processing requirements, and then conducts a preliminary comparative evaluation with the comprehensive processing accuracy index Q to analyze the overall error of the cutting process. The specific evaluation contents are as follows;

[0128] When the comprehensive machining accuracy index Q>accuracy threshold Qth, it indicates that the comprehensive error is abnormal, there is asynchrony of workstation position, mismatch of motor speed, mismatch of motor speed, thermal expansion caused by temperature fluctuation or other errors, then the iterative control process is executed until the comprehensive error stops iteration normally, and the system is re-executed to adjust the control coefficient, predictive compensation and temperature compensation optimization measures through the user;

[0129] When the comprehensive machining accuracy index Q ≤ the accuracy threshold Qth, it means that the comprehensive error is normal and no further adjustment is required.

[0130] In this embodiment, the comprehensive evaluation and correction module of the system realizes comprehensive quantitative evaluation and iterative optimization of processing quality through the cooperation of the data summary unit and the comprehensive evaluation unit. After the compensation mechanism is executed, the data summary unit summarizes the error scores of all stations into a comprehensive processing accuracy index Q, which provides a clear quantitative basis for the overall quality of multi-station processing. The comprehensive evaluation unit compares and evaluates the index Q with the preset accuracy threshold Qth. When the comprehensive processing accuracy index Q> the accuracy threshold Qth, the system determines that there are processing abnormalities such as errors caused by position asynchrony, speed mismatch or thermal expansion, and automatically enters the iterative control process. By adjusting the control coefficient, compensation strategy, etc., the processing process is gradually optimized until the error returns to normal; when the comprehensive processing accuracy index Q≤accuracy threshold Qth, the system determines that the processing accuracy meets the standard and no further adjustment is required. Compared with the traditional method that relies on single-point error or manual quality detection, this module significantly improves the system's ability to control the overall processing quality through comprehensive analysis and dynamic optimization of errors in all stations. By introducing the quantitative indicator Q and automated evaluation and iteration processes, this module achieves closed-loop optimization of processing quality, reduces the scrap rate and downtime costs caused by processing abnormalities, shortens the adjustment cycle, and ensures production stability and consistency.

[0131] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that many changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A machine tool repetitive positioning control system, characterized in that: It includes cutting data acquisition module, data processing module, servo motor synchronous control module, dynamic prediction and compensation module and comprehensive evaluation and correction module; The cutting data acquisition module collects machine tool data in real time by installing a sensor group on the cutting machine tool, and constructs a central control system to transmit the machine tool data to the central control system; The data processing module receives machine tool data in real time in the central control system, pre-processes the machine tool data, obtains a standard data group, performs calculation processing on the standard data group to obtain cutting processing data, and constructs a time series database, and stores the standard data group and the cutting processing data in the time series database; The servo motor synchronous control module calculates the servo motor position adjustment value △P of each station based on the cutting processing data and writes a positioning control program through PLC i At the same time, the speed adjustment algorithm is used to calculate and output the servo motor speed adjustment value S for each station. i , adjust the servo motor position by △P i And the servo motor speed adjustment S i , synchronously adjust the position and speed of the servo motor; The servo motor synchronous control module includes a speed synchronization adjustment unit and a synchronous positioning unit; The speed synchronization adjustment unit extracts the grinding force deviation Efi(t) of the grinding tool at the i-th station at time t through the write port, calculates and outputs the servo motor speed adjustment value S i； The servo motor speed adjustment amount S i The output is calculated by the following algorithm formula; ； In the formula, S i (t) represents the speed adjustment of the servo motor at the i-th station at time t, Sm represents the target speed adjustment of the servo motor, and Fm represents the target cutting force; The synchronous positioning unit is based on the obtained speed adjustment value S of the servo motor of the i-th station at time t. i (t), write the positioning control program through PLC, calculate and obtain the servo motor position adjustment value △P of each station i , dynamically balance the errors of position and velocity; The servo motor position adjustment amount △P i The output is calculated by the following algorithm formula; ； In the formula, Kp l Represents the first compensation gain control coefficient, Kv l Indicates the speed control coefficient, Kc l represents the integral control coefficient, dt represents the time integral variable, △P i (t) represents the position adjustment of the servo motor at time t; The dynamic prediction and compensation module extracts historical cutting processing data to predict and calculate the future position error value E Epi (t+△t), and preset the error threshold E and the future position error value E Epi (t+△t) performs error evaluation. If the error evaluation shows an abnormal error, the compensation mechanism is executed; The dynamic prediction and compensation module includes an error prediction unit, a prediction evaluation unit and an error compensation unit; The error prediction unit extracts the position deviation Epi(t) of the i-th station at time t in the historical data table through the write port after adjusting the servo motor position and the servo motor speed, and predicts the position error value E at time t+△t. Ep，i (t+△t); The position error value E at time t+Δt Epi (t+△t) is calculated by the following algorithm formula; ； In the formula, represents the first-order derivative of the error, It represents the second derivative of the error, the acceleration of the error change, and △t represents the time step of the prediction; The comprehensive evaluation and correction module constructs a comprehensive processing algorithm formula to calculate and output the comprehensive processing accuracy index Q of each station, and performs a secondary comparative evaluation on the preset accuracy threshold Qth and the comprehensive processing accuracy index Q. If the position adjustment is evaluated to be abnormal, the iterative control process is executed; The comprehensive assessment correction module includes a data aggregation unit and a comprehensive assessment unit; After the data aggregation unit has completed the execution through the re-compensation mechanism, the error scores of all workstations are summed up to obtain the comprehensive machining accuracy index Q to quantify the machining quality; The comprehensive machining accuracy index Q is calculated and output by the following algorithm formula: ； The comprehensive evaluation unit performs a preliminary comparative evaluation on the accuracy threshold Qth preset by the user according to the processing requirements and the comprehensive processing accuracy index Q to analyze the overall error of the cutting process. The specific evaluation contents are as follows; When the comprehensive machining accuracy index Q> the accuracy threshold Qth, it means that the comprehensive error is abnormal, and the iterative control process is executed until the comprehensive error is normal and the iteration is stopped; When the comprehensive machining accuracy index Q ≤ the accuracy threshold Qth, it means that the comprehensive error is normal and no further adjustment is required.

2. A machine tool repetitive positioning control system according to claim 1, characterized in that: The cutting data acquisition module includes a data acquisition unit and a data transmission unit; The data acquisition unit collects machine tool data in real time by installing a sensor group on the cutting machine tool; The sensor group includes a photoelectric encoder, a speed environment control module, a force sensor and an infrared temperature sensor; The machine tool data includes the real-time position Pi of the servo motor at the i-th station, the real-time speed Si of the servo motor at the i-th station, the grinding force Fi at the i-th station, and the cutting area temperature Ti at the i-th station; The data transmission unit transmits the machine tool data collected in real time to the central control system by constructing the central control system; The specific transmission method is as follows; Use the industrial bus protocol CAN to transmit the real-time position Pi and real-time speed Si of the servo motor at the i-th station to the central control system; At the same time, the communication modules of the force sensor and the infrared temperature sensor are used to transmit the collected grinding force Fi of the i-th station and the cutting area temperature Ti of the i-th station to the central control system through the Modbus communication protocol.

3. A machine tool repetitive positioning control system according to claim 2, characterized in that: The data processing module includes a preprocessing unit, a calculation processing unit and a data storage unit; The preprocessing unit receives the machine tool data in real time in the central control system, performs data cleaning and normalization on the machine tool data, and marks the machine tool data with a timestamp to obtain a standard data set; The standard data set includes the real-time position Pi(t) of the servo motor at the i-th station at time t, the real-time speed Si(t) of the servo motor at the i-th station at time t, the grinding force Fi(t) at the i-th station at time t, and the cutting area temperature Ti(t) at the i-th station at time t; The calculation processing unit performs calculation processing based on the standard data group to obtain cutting processing data; The cutting processing data includes the position deviation Epi(t) of the i-th station at time t and the grinding force deviation Efi(t) of the grinding tool at the i-th station at time t; The workstation position deviation Epi (t) and grinding force deviation Efi (t) are outputted by the following calculation formulas: ； ； In the formula, n represents the total number of workstation positions; The data storage unit constructs a time series database and sets a write port, a write port, a real-time data table and a historical data table. The standard data group and the cutting processing data acquired in real time are stored in the real-time data table through the write port, and the standard data group and the cutting processing data originally in the real-time data table are automatically transferred to the historical data table and sorted in the order of timestamps.

4. A machine tool repetitive positioning control system according to claim 1, characterized in that: The prediction evaluation unit sets the error threshold E based on the user, and then compares it with the predicted position error value E at time t+Δt. Epi (t+△t) to evaluate the error and analyze the cutting accuracy. The specific evaluation contents are as follows; At time t+△t, the position error value is E Epi When (t+△t)≤error threshold E, it means that the predicted cutting accuracy is abnormal, and the compensation mechanism is executed at this time; At time t+△t, the position error value is E Epi When (t+△t)>error threshold E, it means that the predicted cutting accuracy is normal. At this time, the current control state is maintained without additional compensation.

5. A machine tool repetitive positioning control system according to claim 4, characterized in that: The error compensation unit executes the compensation mechanism when the predicted cutting accuracy is abnormal. The compensation mechanism calculates and outputs the servo motor position compensation value △Pb of the i-th station at time t by introducing the temperature compensation factor AT. i (t); send the servo motor position compensation △Pbi (t) to the servo motor to correct the position in advance; The servo motor position compensation amount △Pbi (t) is calculated and outputted by the following algorithm formula; ； Wherein, Kp2 represents the second compensation gain control coefficient.

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