Linkage operation system of numerical control machine tool

Abstract

The invention provides a numerical control machine tool linkage operation system which comprises a multi-axis error real-time monitoring module, an error coupling dynamic modeling module, a linkage shaft error dynamic compensation control module, a control stability optimization module and a man-machine interaction intelligent guide module. By arranging the multi-axis error real-time monitoring module and the error coupling dynamic modeling module, real-time position information of a plurality of linkage shafts is collected in the operation process of the machine tool, a linkage error dynamic model is constructed based on the information, the linkage coupling influence relation between the shafts is introduced, and the linkage error dynamic modeling is realized. The space superposition state of errors in the multi-axis linkage process is more accurately reflected, the compensation control module is combined to convert the real-time errors predicted by the model into instruction level control correction, and therefore dynamic closed-loop adjustment of linkage shaft displacement is achieved, and the problem of track deviation caused by error coupling between linkage shafts is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of numerical control machine tools, and particularly relates to a numerical control machine tool linkage operating system. Background Art

[0002] In the prior art, numerical control machine tools usually adopt semi-closed-loop control or full-closed-loop control systems to achieve the positioning and linkage operation of the machine tool axes. The semi-closed-loop control system compensates for errors based on the rotation angle of the servo motor itself or the position information fed back by the encoder. However, in actual applications, due to the inevitable elastic deformation, wear, clearance, and non-linear characteristics of the mechanical transmission chain (such as ball screws, gears, couplings, etc.), there is a deviation between the actual machining position of the machine tool and the commanded position. Especially during multi-axis linkage machining, the errors between the axes have a coupling effect, which significantly increases the complexity of the errors. Traditional single-axis or independent-axis error compensation methods are difficult to effectively solve the coupling error problem during multi-axis linkage.

[0003] In addition, although the full-closed-loop control method achieves more accurate positioning by directly measuring the actual position of the machine tool's executing components, its system stability and control complexity also increase accordingly. Especially when the machine tool structure has insufficient rigidity or during high-speed machining, it is prone to problems such as vibration and unstable control, resulting in fluctuations in the machining process, further reducing the actual machining accuracy and reliability, and thus causing the following two problems:

[0004] On the one hand, the accumulated errors during multi-axis linkage machining cannot be effectively corrected in real time, resulting in the machining accuracy of the parts not meeting the requirements for machining high-precision and high-complexity parts.

[0005] On the other hand, the increase in system control complexity leads to higher requirements for the professional skills of operators, which not only affects production efficiency but also causes a reduction in the service life of the machining equipment and an increase in the failure rate.

[0006] Therefore, a numerical control machine tool linkage operating system is proposed. Summary of the Invention

[0007] In view of this, the present invention provides a numerical control machine tool linkage operating system to solve or alleviate the technical problems existing in the prior art, and at least provide a beneficial alternative.

[0008] The technical solution of the present invention is realized as follows: A numerical control machine tool linkage operating system includes a multi-axis error real-time monitoring module, an error coupling dynamic modeling module, a linkage axis error dynamic compensation control module, a control stability optimization module, and a human-machine interaction intelligent guidance module.

[0009] The multi-axis error real-time monitoring module is respectively provided with high-precision position sensors for real-time acquisition of axial actual position information on multiple linked axes of the CNC machine tool, and transmits the position information to the error coupling dynamic modeling module in real time through the CNC bus; the error coupling dynamic modeling module establishes an error dynamic mathematical model including the mutual influence between the linked axes according to the real-time position information of each axis, and calculates and generates the comprehensive error information of the linked axes reflecting the difference between the actual position and the target position of the linked axes in real time; the linked axis error dynamic compensation control module receives the comprehensive error information, generates real-time position correction instructions for each linked axis accordingly, and sends the correction instructions to the servo drive devices of each linked axis through the CNC controller; the control stability optimization module automatically adjusts the control parameters in the correction instructions according to the system vibration signals monitored in real time during the machining process; the human-computer interaction intelligent guidance module includes a CNC system interface for displaying real-time position information, error compensation status, system vibration conditions and alarm prompt information;

[0010] The multi-axis error real-time monitoring module uses high-precision position sensors installed on the X-axis, Y-axis, and Z-axis of the CNC machine tool to collect the current actual position information of each axis in real time and send it to the error modeling module at a high frequency. The error coupling dynamic modeling module constructs a dynamic error mathematical model including the inter-axis coupling relationship based on the received real-time axis position data, and continuously outputs the comprehensive error information describing the deviation between the actual position and the theoretical target position. The linked axis error dynamic compensation control module generates real-time correction control instructions for each linked axis based on this comprehensive error, and directly acts on the corresponding servo drive device through the CNC controller to adjust the execution action trajectory of the axis, realizing the closed-loop control of the error. To ensure the stable operation of the control system during the high-speed dynamic compensation process, the control stability optimization module accesses the real-time vibration monitoring signal and dynamically adjusts the control parameters in the compensation instructions to prevent overshoot or resonance phenomena.

[0011] Further preferably, the multi-axis error real-time monitoring module includes a grating scale or a magnetic grating scale, which is installed on the side of the linear guide of each linked axis. The measurement accuracy of the grating scale is ±0.5μm, the data acquisition frequency is 10,000Hz, and the collected data is synchronously sent to the error coupling dynamic modeling module through the Profinet industrial real-time network at a period of 0.5ms, and double-ended CRC verification is performed. The distance error between the installation position of each axis sensor and the bearing seat or the center line of the guide rail is less than 0.05mm;

[0012] By selecting a grating scale or magnetic scale with an accuracy of ±0.5μm, the basic requirements of the linkage control system for high-resolution axial position feedback are met. The sensor is installed on the side of the guide rail of the linkage axis, arranged close to the stress point, and the control of its installation reference distance is within 0.05mm, effectively reducing the error influence introduced by installation offset. High-frequency sampling at 10000Hz is combined with Profinet real-time industrial network communication and synchronously sent to the subsequent error modeling module at a cycle of 0.5ms to ensure the system's rapid response to the rapidly changing axial position state. During data transmission, double-ended CRC check is adopted to enhance anti-interference ability and transmission stability.

[0013] Further preferably, the linkage error dynamic compensation control module includes an error command calculation unit and a compensation execution unit; the error command calculation unit calculates and generates a real-time compensation control command according to the real-time comprehensive error information output by the error coupling dynamic modeling module; the compensation execution unit converts the real-time compensation control command into a control signal recognizable by the numerical control system and acts on each linkage axis servo drive device;

[0014] By dividing the linkage error dynamic compensation control module into two independent but collaborative sub-units, which respectively undertake the functions of error calculation and execution conversion. The error command calculation unit calculates the position deviation correction amount according to the independent correction strategy of each axis based on the comprehensive error data provided by the dynamic modeling module, combined with the servo parameters of the axis and the actual operating state. The correction amount is timely transmitted to the compensation execution unit, which encapsulates it into a standard control signal according to the numerical control system communication protocol and directly acts on the servo controllers of each linkage axis. The two independent but collaborative sub-units are beneficial for subsequent expansion of different types of control interfaces, effectively reducing data processing delay and improving error response efficiency.

[0015] Further preferably, the linkage error dynamic compensation control module is built-in with a real-time interpolation control program. Based on the data output by the error coupling dynamic modeling module, the real-time error data is converted into specific pulse compensation amounts for the servo axes. The pulse compensation resolution of each axis is 0.001mm / pulse, and the interpolation cycle does not exceed 0.5ms. The compensation command is sent to each axis servo driver through the EtherCAT bus;

[0016] Through the interpolation control program, the error compensation is changed from "discrete control" to "continuous fine correction", which can complete the generation and issuance of pulse-level correction commands once every 0.5ms, ensuring a high-frequency real-time response to the error signal. The high-resolution compensation granularity enables the system to accurately adjust minute trajectory deviations and adapt to the processing tasks of high-precision complex surfaces. At the same time, the use of the EtherCAT bus ensures the real-time performance and reliability of command transmission, effectively reducing the impact of command delay on the compensation effect. This preferred solution improves the system's response speed and compensation accuracy to instantaneous error changes.

[0017] Further preferably, the control stability optimization module includes a vibration monitoring device and a compensation gain adaptive adjustment unit; two high-precision MEMS accelerometers are configured on the bearing block of each linkage axis by the vibration monitoring device, the sampling frequency is not less than 2000 Hz, and the measurement error does not exceed ±0.01 g; the compensation gain adaptive adjustment unit automatically adjusts the PID gain parameters of the compensation control according to the vibration spectrum characteristics monitored in real time;

[0018] By using a high-frequency MEMS acceleration sensor to capture subtle changes in the structural response, and combining spectrum feature recognition, it dynamically identifies whether machining resonance and structural instability occur, and automatically adjusts the PID parameters through the gain adaptive adjustment unit to prevent overcompensation or oscillation caused by improper gain settings, and enhance the stability of the compensation system under dynamic high load and non-ideal working conditions.

[0019] Further preferably, the human-machine interaction intelligent guidance module includes a real-time axis position display interface and a compensation data setting interface; the real-time axis position display interface shows the deviation change between the actual position and the theoretical position of each linkage axis in the form of a curve, and the data refresh frequency is 50 Hz; the compensation data setting interface can input a compensation threshold, and the threshold adjustment range is from ±0.001 mm to ±0.05 mm, and the adjustment step is 0.0005 mm;

[0020] This preference enables the operator to intuitively master the axis position deviation and compensation status during the machining process, especially to detect problems such as "layer-by-layer offset" or "periodic error drift" that are difficult to capture by the alarm system. Through the graphical curve display, the error trend is clear, which is conducive to technicians making quick judgments.

[0021] Further preferably, the linkage error dynamic compensation control module is built with an error limiting unit, and the limiting threshold ranges from ±0.001 mm to ±0.1 mm according to different machining materials, machine tool stiffness and process requirements; it also includes a current saturation protection unit, and the maximum allowable current of the servo motor is set to 150% of the rated current. When the drive current exceeds the limit, the output of the compensation command is automatically limited;

[0022] Through the error limiting module, it is possible to avoid overly large compensation commands in the case of sudden error changes or abnormal model states, prevent shaft system impacts and workpiece damage, and the current saturation protection provides hardware-level current safety protection for the servo motor. Under abnormal working conditions of the motor or load, such as tool jamming and sudden increase in load, the compensation action can be automatically reduced to prevent the servo from overheating, getting out of control or even burning out due to current overload.

[0023] Further preferably, the vibration monitoring device is built with a vibration abnormal state classification library, which contains no less than 100 groups of typical vibration characteristic spectra. After the vibration data collected in real time is analyzed by FFT spectrum analysis, it is matched with the data in the vibration abnormal state classification library;

[0024] Through the preset vibration characteristic library, the originally "unquantifiable" vibration behavior is converted into "identifiable and classifiable" structural information, realizing the analog diagnosis of the machine tool structure state. After spectrum analysis, by comparing with the database, typical abnormalities such as bearing looseness, lead screw jumping, and local interference of the guide rail can be identified.

[0025] Due to the adoption of the above technical solutions in the embodiments of the present invention, it has the following advantages:

[0026] First, by setting up a multi-axis error real-time monitoring module and an error coupling dynamic modeling module, the present invention realizes the acquisition of the real-time position information of multiple linked axes during the operation of the machine tool, constructs a linked error dynamic model based on this information, and introduces the linked coupling influence relationship between axes, more accurately reflecting the spatial superposition state of errors during multi-axis linkage. Combining with the compensation control module, the real-time error predicted by the model is converted into command-level control correction, thereby realizing the dynamic closed-loop adjustment of the displacement of the linked axes, effectively reducing the trajectory deviation problem caused by the error coupling between the linked axes.

[0027] Second, the control stability optimization module of the present invention realizes the real-time monitoring of the dynamic response and micro-vibration state of the machine tool during the error compensation process by arranging MEMS acceleration sensors at key parts of the linked axes; cooperating with the embedded spectrum recognition algorithm module, it can identify the structural resonance or high-frequency vibration trend caused by error compensation, and according to the monitoring results, micro-adjust the PID control parameters in the compensation controller in real time to ensure that while maintaining the error closed-loop accuracy, it avoids system oscillation caused by over-compensation or mis-compensation, and improves the stability and adaptability of the system operation.

[0028] The above summary is only for the purpose of the specification and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present invention will be readily apparent by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0030] Figure 1 This is the system module relationship diagram of the present invention. Detailed implementation manners

[0031] In the following text, only some exemplary embodiments are briefly described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present invention. Therefore, the drawings and the description are considered to be exemplary in nature rather than restrictive.

[0032] The embodiments of the present invention will be described in detail below with reference to the drawings.

[0033] Embodiment

[0034] As Figure 1 shown, this embodiment provides a numerical control machine tool linkage operating system. The system includes: a multi-axis error real-time monitoring module, an error coupling dynamic modeling module, a linkage axis error dynamic compensation control module, a control stability optimization module, and a human-computer interaction intelligent guidance module. Information interaction is realized between each module through an industrial bus, forming a closed-loop linkage control system;

[0035] The multi-axis error real-time monitoring module respectively installs grating scales as position sensors on the linkage axes of the X-axis, Y-axis, and Z-axis of the machine tool. The measurement accuracy of the grating scale is ±0.5μm, and it is installed on the side of the linear guide of each axis; through dedicated wiring, the collected position information is synchronously transmitted to the central processing unit of the system at a period of 0.5ms, using the Profi net real-time Ethernet communication protocol, and at the same time, each frame of data is attached with double-ended CRC verification to ensure the reliability of the transmission process; the installation reference of each position sensor and the error of the guide rail center do not exceed 0.05mm, ensuring the authenticity and effectiveness of the axis position acquisition;

[0036] The error coupling dynamic modeling module establishes a coupling error mathematical model in a three-dimensional linkage coordinate system based on the collected three-axis axis position data. The coupling error mathematical model uses the state space method and is dynamically corrected in combination with the machining trajectory; the error variables in the model include axial displacement error, pitch error, linear error caused by thermal expansion, and linkage coupling error. The model iterates once every 0.5ms and outputs the current instantaneous comprehensive error information;

[0037] The linkage axis error dynamic compensation control module includes an error command calculation unit and a compensation execution unit; the error command calculation unit converts the error information output by the above modeling module into a linkage axis correction control value, and the calculation method is to map the error value to a pulse compensation amount; for example, when there is a negative deviation of -3μm on the Z axis, according to the preset compensation resolution of 0.001mm / pulse, a positive compensation of 3 pulse lengths is generated; this compensation amount is sent to the EtherCAT servo drive command channel through the compensation execution unit, and the drive responds to the compensation action and corrects the axis motion trajectory in real time, and the interpolation period is kept within 0.5ms;

[0038] To control the oscillation of the control system caused by error compensation, two MEMS acceleration sensors with directions perpendicular to each other at 90° are arranged at the bearing seat position of each linkage axis through the control stability optimization module, with a sampling frequency of 2000Hz, and the vibration acceleration signal is collected in real time; the frequency components causing the control oscillation are identified through wavelet packet decomposition and FFT spectrum analysis, and then the PID parameters are fine-tuned by the gain adjustment unit to control the change of its proportional factor within the range of ±10%, so as to maintain the smoothness of the drive output;

[0039] The human-machine interaction intelligent guidance module displays a number of monitoring information through the touch control numerical control system interface, including the theoretical displacement curve of each axis, the real-time actual displacement curve, the deviation data change graph, the current error compensation amount, and the vibration state; among them, the real-time data display frequency is set to 50Hz, and the update and refresh are without delay; at the same time, in the compensation setting interface, the operator is allowed to set the compensation limit threshold for each axis. For example, the X axis can be set to ±0.02mm, and the error correction amount is limited according to the set value;

[0040] In this embodiment, an error limiting logic circuit and a current saturation protection circuit are configured in the compensation control module. For different machining materials and tool rigidity requirements, by setting different axial error limiting ranges (±0.001mm to ±0.1mm), in current protection, when the feedback current of the servo drive exceeds 150% of the rated current, the system will limit the current compensation amplitude to prevent the drive from overloading;

[0041] During the operation of the system, if the vibration monitoring module identifies a signal in the spectrum that is similar to the stored typical abnormal mode, it will immediately match it through the vibration abnormal state classification library; the system database contains the vibration spectrum characteristics of 100 common abnormal states of machine tool operation, such as bearing looseness, increased backlash, etc. Once the identification is successful, the system will give a text prompt on the interface and recommend the corresponding gain adjustment plan.

[0042] In the application, the data acquisition frequency is set to 100Hz. The system synchronously stores the key data of the position error of each axis, servo current, vibration intensity and compensation command. Each processing task is saved as an independent file, and the single processing capacity can reach 500MB. After the task is completed, the operator can input the work order number to call back the historical data and analyze the error and control behavior through the graphical interface.

[0043] The CNC machine tool linkage operating system provided by this embodiment constructs a closed-loop linkage control operating system with real-time error monitoring, coupling modeling, dynamic compensation, stable control and human-computer interaction. By arranging high-precision grating scale sensors on the X / Y / Z axes of the machine tool and combining with the Profi net network, high-frequency synchronous acquisition of micron-level axis position data is realized. The modeling module constructs a state space error model including the inter-axis coupling relationship and outputs the three-dimensional machining error in real time. The compensation control module quantifies and calculates this error and performs pulse mapping, dynamically correcting the axis trajectory at a resolution of 0.001mm / pulse. The compensation command acts on the servo driver through the EtherCAT bus after interpolation. At the control level, through the bidirectional acceleration sensor and the FFT analysis algorithm, the structural resonance is identified in real time and the PID control gain is adjusted, so as to realize the dynamic closed-loop adjustment of the linkage axis displacement, effectively reducing the trajectory deviation problem caused by the error coupling between the linkage axes; at the same time, a limit logic and a current protection circuit are configured to enhance the safety and adaptability of the compensation action. The human-computer interaction module presents the deviation curves of each axis in real time at a refresh rate of 50Hz, and supports the configuration of error limits and the backtracking of historical work order data. By means of the preset vibration feature library, the originally "unquantifiable" vibration behavior is transformed into "identifiable and classifiable" structural information, realizing the analog diagnosis of the machine tool structure state. After spectrum analysis, by comparing with the database, typical abnormalities such as bearing looseness, lead screw jumping, and local interference of the guide rail can be identified.

[0044] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of various changes or substitutions within the technical scope disclosed by the present invention, and these should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A linked operating system for a numerical control machine tool, characterized in that: It includes a multi-axis error real-time monitoring module, an error coupling dynamic modeling module, a linked-axis error dynamic compensation control module, a control stability optimization module, and a human-machine interaction intelligent guidance module; The multi-axis error real-time monitoring module is respectively provided with high-precision position sensors for real-time obtaining axial actual position information on multiple linked axes of a numerically controlled machine tool, and transmits the position information to the error coupling dynamic modeling module in real time through a numerical control bus; the error coupling dynamic modeling module establishes an error dynamic mathematical model including the mutual influence between linked axes according to the real-time position information of each axis, and calculates and generates linked-axis comprehensive error information reflecting the difference between the actual position and the target position of the linked axes in real time; the linked-axis error dynamic compensation control module receives the comprehensive error information, generates real-time position correction instructions for each linked axis accordingly, and sends the correction instructions to the servo drive devices of each linked axis through a numerical control controller; the control stability optimization module automatically adjusts the control parameters in the correction instructions according to the system vibration signals monitored in real time during the machining process; the human-machine interaction intelligent guidance module includes a numerical control system interface for displaying real-time position information, error compensation status, system vibration conditions, and alarm prompt information.

2. The linkage operating system of a numerically controlled machine tool according to claim 1, characterized in that: The multi-axis error real-time monitoring module includes a grating scale or a magnetic grating scale, which is installed on the side of the linear guide of each linked axis. The measurement accuracy of the grating scale is ±0.5μm, the data acquisition frequency is 10000Hz, and the collected data is synchronously sent to the error coupling dynamic modeling module through a Profinet industrial real-time network at a period of 0.5ms, and double-ended CRC verification is performed. The distance error between the installation position of each axis sensor and the bearing seat or the center line of the guide rail is less than 0.05mm.

3. The linkage operating system of a numerically controlled machine tool according to claim 1, characterized in that: The linked error dynamic compensation control module includes an error instruction calculation unit and a compensation execution unit; the error instruction calculation unit calculates and generates real-time compensation control instructions according to the real-time comprehensive error information output by the error coupling dynamic modeling module; the compensation execution unit converts the real-time compensation control instructions into control signals recognizable by the numerical control system and acts on the servo drive devices of each linked axis.

4. A linkage operating system for a numerical control machine tool according to claim 1, characterized in that: The linked error dynamic compensation control module is built-in with a real-time interpolation control program. Based on the data output by the error coupling dynamic modeling module, the real-time interpolation control program converts the real-time error data into specific pulse compensation amounts of the servo axes. The pulse compensation resolution of each axis is 0.001mm / pulse, the interpolation period does not exceed 0.5ms, and the compensation instructions are sent to the servo drivers of each axis through an EtherCAT bus.

5. A linkage operating system for a numerical control machine tool according to claim 1, characterized in that: The control stability optimization module includes a vibration monitoring device and a compensation gain adaptive adjustment unit; the vibration monitoring device is configured with two high-precision MEMS accelerometers on the bearing seat of each linked axis, the sampling frequency is not less than 2000Hz, and the measurement error does not exceed ±0.01g; the compensation gain adaptive adjustment unit automatically adjusts the PID gain parameters of the compensation control according to the vibration spectrum characteristics monitored in real time.

6. A CNC machine tool linkage operating system according to claim 1, characterized in that: The human-machine interaction intelligent guidance module includes a real-time axial position display interface and a compensation data setting interface. The real-time axial position display interface shows the deviation changes between the actual positions and the theoretical positions of each linkage axis in the form of a curve, and the data refresh frequency is 50Hz.

7. The linkage operating system of a numerical control machine tool according to claim 6, wherein: The compensation data setting interface can input a compensation threshold, and the threshold adjustment range is from ±0.001mm to ±0.05mm, and the adjustment step is 0.0005mm.

8. The linkage operating system of a numerical control machine tool according to claim 3, wherein: The linkage error dynamic compensation control module is built-in with an error limiting unit, and the limiting threshold can be adjusted according to different processing materials, machine tool stiffness and process requirements, and the adjustment range is from ±0.001mm to ±0.1mm.

9. The linkage operating system of a numerical control machine tool according to claim 8, characterized in that: The linkage error dynamic compensation control module also includes a current saturation protection unit. The maximum allowable current of the servo motor is set to 150% of the rated current. When the drive current exceeds the limit, the output of the compensation command is automatically limited.

10. A linked operating system for a numerical control machine tool according to claim 5, characterized in that: The vibration monitoring device is built-in with a vibration abnormal state classification library, and the vibration abnormal state classification library contains no less than 100 groups of typical vibration characteristic spectra. After the vibration data collected in real time is subjected to FFT spectrum analysis, it is matched with the data in the vibration abnormal state classification library.

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