Guide rail dynamic error real-time compensation system based on multi-sensor fusion

Abstract

The invention provides a guide rail dynamic error real-time compensation system based on multi-sensor fusion, and relates to the technical field of guide rail precision compensation, and the system comprises a calling module which is used for calling and traversing a temperature sequence database, and obtaining a target temperature sequence matched with a target working condition; the prediction module is configured to construct a finite element model of the guide rail, and is combined with the target temperature sequence to obtain a predicted straightness sequence of the guide rail so as to obtain a straightness error sequence; the judgment module is configured to traverse the straightness error sequence so as to take a point location corresponding to the predicted straightness corresponding to the straightness error greater than the preset precision as a to-be-compensated point location; the compensation module is configured to obtain a corresponding thermal deformation compensation amount according to the straightness error corresponding to each to-be-compensated point position, and compensate the straightness error of each to-be-compensated point position by the thermal deformation compensation amount in the operation process of the guide rail under the target working condition through the distributed piezoelectric ceramic array, so as to compensate the straightness error of each to-be-compensated point position. And a more reliable precision guarantee is provided for high-precision machining equipment.

Description

Technical Field

[0001] This application relates to the technical field of guide rail precision compensation, and specifically relates to a real-time compensation system for dynamic errors of guide rails based on multi-sensor fusion. Background Art

[0002] In high-precision machining fields such as numerically controlled machine tools, the dynamic error compensation technology of guide rails is the core link to ensure machining accuracy.

[0003] In the prior art, a method for dynamically adjusting the precision of the guide rail of a large-scale numerically controlled gantry milling machine bed proposed in the invention patent with the publication number of CN118768620 A discloses the active control of guide rail precision through finite element modeling and motion parameter optimization.

[0004] However, this technology relies on the finite element model to obtain the straightness of the guide rail, ignoring the influence of the dynamic change of the temperature field on the thermal deformation of the guide rail under actual working conditions. In actual working conditions, the frictional heat generated by the high-speed movement of moving parts and the environmental temperature fluctuation will cause a thermal elongation of millimeter level, resulting in the failure of traditional mechanical compensation methods and restricting the machining accuracy of high-end equipment. Summary of the Invention

[0005] In view of the above defects or deficiencies in the prior art, this application aims to provide a real-time compensation system for dynamic errors of guide rails based on multi-sensor fusion to accurately compensate the dynamic errors of the guide rails; the compensation system includes: A retrieval module, which is configured to retrieve and traverse a temperature sequence database to obtain a target temperature sequence matching the target working condition; the temperature sequence database includes multiple groups of historical working conditions and the corresponding historical temperature sequences for each group of historical working conditions. The historical working conditions include the moving speed, acceleration, and load distribution of the moving parts slidingly connected to the guide rail. The historical temperature sequences include the temperatures corresponding to multiple points distributed along the extension direction of the guide rail. The target temperature sequence is the historical temperature sequence corresponding to the historical working condition matching the target working condition; A prediction module, which is configured to build a finite element model of the guide rail and, in combination with the target temperature sequence, obtain a predicted straightness sequence of the guide rail under the working state corresponding to the target working condition, and then obtain a straightness error sequence; the predicted straightness sequence includes the predicted straightness corresponding to multiple points, and the straightness error sequence includes multiple straightness errors. The straightness error is the absolute value of the difference between the predicted straightness and the preset straightness; A judgment module, which is configured to traverse the straightness error sequence to judge whether there is a straightness error greater than the preset accuracy in the straightness error sequence; if so, the point corresponding to the predicted straightness with the straightness error greater than the preset accuracy is used as the point to be compensated; A compensation module, which is configured to obtain corresponding thermal deformation compensation amounts according to the straightness errors corresponding to each point to be compensated, and during the operation of the guide rail under the target working condition, compensate the straightness errors of each point to be compensated with the thermal deformation compensation amounts through a distributed piezoelectric ceramic array; the distributed piezoelectric ceramic array is composed of a plurality of piezoelectric ceramic units respectively arranged at each point.

[0006] According to the technical solution provided by the present application, the compensation module includes: A real-time sensing unit, which is configured to collect real-time temperature data, load pressure data and vibration spectrum data of each point during the operation of the guide rail under the target working condition; A dynamic correction unit, which is configured to perform differential calculation on the real-time temperature data and load pressure data with the target temperature sequence to generate a temperature drift correction coefficient and a load correction coefficient, and calculate a stiffness attenuation factor according to the vibration spectrum data; An online compensation optimization unit, which is configured to obtain an updated thermal deformation compensation amount based on the temperature drift correction coefficient, the load correction coefficient and the stiffness attenuation factor, so that the distributed piezoelectric ceramic array adjusts the thermal deformation compensation amount in real time according to the updated thermal deformation compensation amount.

[0007] According to the technical solution provided by the present application, according to to obtain the updated thermal deformation compensation amount; wherein, represents the updated thermal deformation compensation amount, represents the thermal deformation compensation amount, represents the temperature drift correction coefficient, represents the load correction coefficient, represents the stiffness attenuation factor.

[0008] According to the technical solution provided by the present application, the points include micro-deformation sensitive points on the sliding surface of the guide rail, and / or stress concentration points of the moving part, and / or vibration transmission nodes of the guide rail foundation support structure.

[0009] According to the technical solution provided by the present application, if the piezoelectric ceramic unit is arranged at the micro-deformation sensitive point on the sliding surface of the guide rail, the piezoelectric ceramic units are arranged in a honeycomb topology, and the distance between adjacent piezoelectric ceramic units is less than the heat conduction wavelength.

[0010] According to the technical solution provided by the present application, if the piezoelectric ceramic unit is arranged at the stress concentration point of the moving part, the piezoelectric ceramic unit is integrally packaged with a strain gauge to form a force-electricity coupling feedback link.

[0011] According to the technical solution provided by the present application, if the piezoelectric ceramic unit is disposed at the vibration transfer node of the guide rail foundation support structure, the piezoelectric ceramic unit is connected in parallel with the active damper, and the compensation mode is switched according to the stiffness attenuation factor; The switching of the compensation mode according to the stiffness attenuation factor includes: If the stiffness attenuation factor is greater than the preset attenuation factor, deformation compensation is performed; If the stiffness attenuation factor is less than or equal to the preset attenuation factor, switch to the vibration energy absorption mode; Wherein, the value range of the preset attenuation factor is between 0.65 and 0.8.

[0012] According to the technical solution provided by the present application, the temperature drift correction coefficient is the product of the temperature base correction coefficient and the weight factor of the temperature base correction coefficient; the dynamic correction unit is further configured to: If the instantaneous temperature change rate of the real-time temperature data and the target temperature sequence exceeds the set threshold, or an abnormal harmonic component appears in the vibration spectrum data, then trigger the compensation enhancement mode; the compensation enhancement mode includes: Dynamically adjust the weight factor of the temperature base correction coefficient based on the temperature mutation direction; Perform an inverse Fourier transform on the abnormal harmonic component to generate a time-domain reverse excitation signal, the signal phase of the time-domain reverse excitation signal is offset by 180° ± 5°, and the amplitude is 120% - 150% of the energy of the abnormal harmonic component; Output the time-domain reverse excitation signal through the distributed piezoelectric ceramic array to cancel the vibration energy.

[0013] According to the technical solution provided by the present application, the compensation module is further configured to: Real-time monitor the working state of the piezoelectric ceramic units at each compensation point to be compensated, and determine whether there is a failure point; the failure point is a compensation point to be compensated where the current deviation rate is greater than the first preset threshold and continues to be greater than the first preset duration; If so, take the failure point as the center, and select the piezoelectric ceramic units at the adjacent points within the first preset radius to form a compensation sub-network; Re-distribute the thermal deformation compensation amount corresponding to the failure point into sub-compensation amounts to the compensation sub-network.

[0014] According to the technical solution provided by the present application, after determining whether there is a failure point, the compensation module is further configured to: If so, apply a reverse voltage gradient to the piezoelectric ceramic unit at the micro-deformation sensitive point to cool down the area of the failure point until the instantaneous temperature change rate of the real-time temperature data and the target temperature sequence is within the set threshold.

[0015] Compared with the prior art, the beneficial effects of the present application are as follows: By injecting the historical temperature sequence into the finite element model, the present application accurately quantifies the thermal deformation of the guide rail caused by frictional heat and temperature fluctuations under working conditions, solving the problem of missing temperature field modeling. At the same time, the prediction module combines the finite element model with the target temperature sequence to generate a predicted straightness error sequence of the guide rail under the target working conditions, and the judgment module screens the points to be compensated that need to be compensated, identifies the error distribution in advance, and combines the distributed piezoelectric ceramic array to perform dynamic compensation on specific points, suppressing the thermal deformation error within the preset accuracy, significantly improving the machining accuracy. In addition, by using distributed piezoelectric ceramic units, the corresponding thermal deformation compensation amount is generated for the straightness error of the points to be compensated, realizing real-time fine adjustment of local deformation. The high-frequency response characteristics of the piezoelectric ceramics can adapt to the transient thermal deformation under the high-speed movement of the moving parts, overcoming the hysteresis problem of traditional mechanical compensation mechanisms and ensuring that the compensation action is synchronized with the thermal deformation. In summary, the present application solves the problem of millimeter-level thermal deformation compensation failure caused by ignoring temperature field changes in traditional methods, upgrades the dynamic error control of the guide rail from passive adjustment to active suppression, and provides a more reliable accuracy guarantee for high-precision machining equipment such as numerically controlled machine tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 FIG. is a schematic structural diagram of a real-time compensation system for dynamic errors of a guide rail based on multi-sensor fusion provided by the present application.

[0017] The text markings in the figure are as follows: 1. Retrieval module; 2. Prediction module; 3. Judgment module; 4. Compensation module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The present application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the related invention and not for limiting the invention. In addition, it should be noted that only the parts related to the invention are shown in the drawings for the convenience of description.

[0019] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and embodiments.

[0020] Embodiment 1 As mentioned in the background art, in view of the problems in the prior art, the present application proposes a real-time compensation system for dynamic errors of a guide rail based on multi-sensor fusion, as Figure 1 shown, including: Retrieval module, the retrieval module is configured to retrieve and traverse the temperature sequence database to obtain a target temperature sequence that matches the target working condition; the temperature sequence database includes multiple groups of historical working conditions and the corresponding historical temperature sequences for each group of historical working conditions. The historical working conditions include the moving speed, acceleration, and load distribution of a moving component slidably connected to the guide rail. The historical temperature sequence includes the temperatures corresponding to multiple points distributed along the extension direction of the guide rail. The target temperature sequence is the historical temperature sequence corresponding to the historical working condition that matches the target working condition; Specifically, the temperature sequence database is obtained by collecting the information in each historical working condition through the real-time sensing unit mentioned later. Among them, the historical working condition includes information such as the moving speed, acceleration, and load distribution of the moving component slidably connected to the guide rail. These information reflect the external conditions of the guide rail in different working states. The historical temperature sequence records the temperatures corresponding to multiple points distributed along the extension direction of the guide rail, reflecting the temperature distribution of the guide rail under the corresponding working conditions. The target working condition refers to the working condition when error compensation needs to be performed on the guide rail, including parameters such as the moving speed, acceleration, and load distribution of the moving component. By matching the target working condition with the historical working conditions in the temperature sequence database, the corresponding target temperature sequence is obtained.

[0021] Prediction module, the prediction module is configured to construct a finite element model of the guide rail, and combine with the target temperature sequence to obtain a predicted straightness sequence of the guide rail under the working state corresponding to the target working condition, and further obtain a straightness error sequence; the predicted straightness sequence includes the predicted straightness corresponding to multiple points, and the straightness error sequence includes multiple straightness errors. The straightness error is the absolute value of the difference between the predicted straightness and the preset straightness; Specifically, using professional finite element analysis software, according to parameters such as the material properties, geometric shape, and boundary conditions of the guide rail, a finite element model of the guide rail is established. The finite element model accurately simulates the mechanical behavior of the guide rail under different temperature conditions, providing a scientific calculation method for predicting the straightness error. Exemplarily, for a metal guide rail, material parameters such as the elastic modulus and Poisson's ratio of the metal, as well as geometric parameters such as the length and cross-sectional shape of the guide rail, need to be input to accurately construct the finite element model. Input the target temperature sequence into the established finite element model, and through the calculation of the finite element analysis software, obtain the predicted straightness of each point of the guide rail under the target working condition, thereby generating a predicted straightness sequence. Then, compare the predicted straightness with the preset straightness, calculate the absolute value of the difference, and obtain the straightness error sequence. This process is to quantify the straightness error of the guide rail under the target working condition, providing a basis for determining the points to be compensated later. For example, if the preset straightness is 0 and the predicted straightness of a certain point is 0.01 mm, then the straightness error of this point is 0.01 mm.

[0022] A judgment module, configured to traverse the straightness error sequence to determine whether there is a straightness error greater than a preset accuracy in the straightness error sequence; if so, the points corresponding to the predicted straightness of the straightness error greater than the preset accuracy are used as the points to be compensated. Further, the points include micro-deformation sensitive points on the sliding surface of the guide rail, and / or stress concentration points of the moving part, and / or vibration transfer nodes of the guide rail foundation support structure.

[0023] Specifically, the micro-deformation sensitive points are determined by analyzing the microstructure of the guide rail material and combining the stress distribution of the guide rail sliding surface under different working conditions through finite element simulation, so as to find out the regions that will produce large deformations under small stress changes, thereby identifying the micro-deformation sensitive points. For example, when analyzing a certain aluminum alloy guide rail, the microstructure of the material is observed using an electron microscope, and at the same time, the stress distribution of the guide rail under different loads and temperatures is simulated with the help of finite element software. It is found that some points near the grain boundaries on the surface of the guide rail are significantly deformed when subjected to small stresses, and these points are determined as micro-deformation sensitive points. The stress concentration points are determined by performing a mechanical analysis of the moving part, considering the shape of the part, the connection method, and the external forces applied. For example, in a moving part with a cantilever structure, the root of the cantilever becomes a stress concentration point due to the sudden change in geometric shape and the large bending moment it bears. The position of the stress concentration point can be determined by methods such as theoretical mechanics calculation, finite element simulation, and actual stress testing (such as using strain gauges to measure stress). The vibration transfer nodes are determined by performing a vibration modal analysis of the guide rail foundation support structure and using vibration testing equipment (such as acceleration sensors, laser vibrometers, etc.) to measure the vibration responses at different positions, and analyzing the propagation path and distribution of vibration energy. Those connection points or parts with obvious changes in vibration response and significant influence on the overall vibration state are the vibration transfer nodes. For example, in a guide rail foundation support structure composed of multiple support beams, it is found through vibration testing that the transfer of vibration energy is concentrated at the connection nodes between the beams, and these nodes are determined as vibration transfer nodes.

[0024] Based on the principle of precise positioning and targeted control of the key parts of the guide rail system, this embodiment accurately identifies micro-deformation sensitive points, stress concentration points, and vibration transfer nodes, arranges piezoelectric ceramic units at these positions that have the greatest impact on the performance of the guide rail, and uses the piezoelectric effect of the piezoelectric ceramics to precisely control the deformation, stress, and vibration of the guide rail, thereby effectively compensating for the straightness error of the guide rail.

[0025] A compensation module, configured to obtain corresponding thermal deformation compensation amounts according to the straightness errors corresponding to the points to be compensated, and during the operation of the guide rail under the target working conditions, compensate the straightness errors of the points to be compensated with the thermal deformation compensation amounts through a distributed piezoelectric ceramic array; the distributed piezoelectric ceramic array is composed of a plurality of piezoelectric ceramic units respectively arranged at each point.

[0026] Specifically, the preset accuracy is set according to the actual usage requirements and accuracy standards of the guide rail. By determining the points to be compensated, the specific positions that need error compensation can be clarified, improving the pertinence and effectiveness of compensation. Optionally, the preset accuracy is 0.005 mm. When the straightness error of a certain point is 0.008 mm, this point is the point to be compensated. Piezoelectric ceramic units are installed at multiple points on the guide rail to form a distributed piezoelectric ceramic array. The installation positions are usually selected at points that are more sensitive to the straightness error of the guide rail, such as the micro-deformation sensitive points on the sliding surface of the guide rail, the stress concentration points of the moving parts, and the vibration transfer nodes of the guide rail foundation support structure, etc. The reason for such a setting is that these points are more likely to have straightness errors during the operation of the guide rail. By setting piezoelectric ceramic units at these positions, the errors can be compensated more effectively.

[0027] Describe the principle of the technical solution: First, the system finds the target temperature sequence matching the target working condition from the temperature sequence database through the retrieval module. Since historical experience shows that similar working conditions will lead to similar temperature distributions, and temperature has a significant impact on the straightness of the guide rail. Then, using the finite element model of the guide rail constructed by the prediction module and combining with the target temperature sequence, the thermal deformation of the guide rail under the target working condition is simulated, and the predicted straightness of each point is calculated to obtain the predicted straightness sequence. This is based on the principles of heat conduction and thermoelastic mechanics. Temperature changes will cause the expansion or contraction of the guide rail material, thus causing the shape of the guide rail to change. Next, by comparing the predicted straightness with the preset straightness, the straightness error sequence is obtained. The judgment module traverses the straightness error sequence and finds the points where the straightness error is greater than the preset accuracy as the points to be compensated. Finally, the compensation module calculates the thermal deformation compensation amount according to the straightness error corresponding to each point to be compensated, and uses the inverse piezoelectric effect of the piezoelectric ceramics to apply corresponding voltages to each point to be compensated during the operation of the guide rail through the distributed piezoelectric ceramic array, so that it generates deformation, thereby compensating for the straightness error. Through this technical solution, real-time compensation of the dynamic error of the guide rail can be achieved, and the motion accuracy of the guide rail can be improved. Specifically, by establishing a temperature sequence database and matching the corresponding temperature sequence according to the target working condition, and using the finite element model to predict the straightness error, the error situation of the guide rail under different working states can be accurately analyzed. Determining the points to be compensated and performing real-time compensation through the distributed piezoelectric ceramic array effectively reduces the straightness error of the guide rail and improves the accuracy of the guide rail. For example, during the machining process of a machine tool, improving the accuracy of the guide rail can make the error of the tool during movement smaller, thereby improving the accuracy of the machined parts, reducing the scrap rate, and improving the production efficiency and product quality.

[0028] In a preferred embodiment, the compensation module includes: A real-time sensing unit configured to collect real-time temperature data, load pressure data, and vibration spectrum data of each point during the operation of the guide rail under the target working condition; Specifically, the real-time sensing unit obtains the corresponding data by installing temperature sensors, pressure sensors, and vibration sensors at each point of the guide rail. These sensors are installed to monitor the actual state changes of the guide rail during operation in real time, because these factors will all affect the straightness of the guide rail. For example, sudden temperature changes cause more severe local thermal expansion and contraction of the guide rail, uneven distribution of the load pressure causes additional deformation of the guide rail, and vibration also affects the stability of the guide rail. By collecting these data in real time, abnormal changes in the actual operating state of the guide rail can be detected in a timely manner, providing a data basis for subsequent dynamic correction. A dynamic correction unit, which is configured to perform differential calculation on the real-time temperature data, load pressure data and the target temperature sequence to generate a temperature drift correction coefficient and a load correction coefficient, and calculate a stiffness attenuation factor according to vibration spectrum data; An online compensation and optimization unit, which is configured to obtain an updated thermal deformation compensation amount based on the temperature drift correction coefficient, the load correction coefficient, and the stiffness attenuation factor, so that the distributed piezoelectric ceramic array adjusts the thermal deformation compensation amount in real time according to the updated thermal deformation compensation amount.

[0029] Specifically, since the temperature during actual operation may deviate from the target temperature predicted by the finite element model before, the thermal deformation compensation amount can be adjusted accordingly through the temperature drift correction coefficient. Similarly, the load pressure data is compared and analyzed with the expected load condition under the target working condition to generate a load correction coefficient to consider the influence of load changes on the guide rail deformation. For example, if the real-time temperature is higher than the target temperature, the temperature drift correction coefficient will increase accordingly, and the compensation amount for thermal deformation needs to be increased. The dynamic correction unit analyzes the vibration characteristics of the guide rail according to the vibration spectrum data and calculates the stiffness attenuation factor through a specific algorithm. The vibration of the guide rail will cause a change in its stiffness, and the change in stiffness will affect the effect of thermal deformation compensation. Therefore, it is necessary to calculate the stiffness attenuation factor to adjust the compensation amount. For example, when high-frequency vibration components appear in the vibration spectrum, it means that the stiffness of the guide rail has decreased, and at this time the stiffness attenuation factor will decrease accordingly. The online compensation and optimization unit adjusts the original thermal deformation compensation amount according to the temperature drift correction coefficient, the load correction coefficient, and the stiffness attenuation factor according to a certain calculation formula to obtain the updated thermal deformation compensation amount. This process comprehensively considers various actual factor changes during the operation of the guide rail, enabling the thermal deformation compensation amount to more accurately adapt to the real-time state of the guide rail. For example, when the temperature drift correction coefficient increases, the load correction coefficient increases, and the stiffness attenuation factor decreases, the updated thermal deformation compensation amount will increase accordingly to better compensate for the deformation of the guide rail.

[0030] This embodiment can dynamically correct and optimize the thermal deformation compensation amount, further improving the accuracy of real-time compensation for the dynamic error of the guide rail. By collecting and analyzing various operation data in real time, corresponding correction coefficients and factors are generated, enabling the compensation amount to be adjusted in a timely manner as the actual operation state of the guide rail changes. For example, during the long-term operation of a machine tool, the temperature may gradually increase, and the load condition may also change. Through this embodiment, the compensation amount can be adjusted in real time to maintain the high-precision operation of the guide rail, thereby improving the stability of processing and the consistency of product quality.

[0031] Further, according to obtain the updated thermal deformation compensation amount; where Indicates the thermal deformation compensation amount after update, Indicates the thermal deformation compensation amount, Indicates the temperature drift correction coefficient, Indicates the load correction coefficient, Indicates the stiffness decay factor.

[0032] Specifically, the temperature drift correction coefficient is obtained by the dynamic correction unit through differential calculation of the real-time temperature data and the target temperature sequence. The specific calculation method can be to calculate the difference between the real-time temperature and the target temperature, and then combine a certain proportional relationship to obtain the temperature drift correction coefficient. For example, if the real-time temperature is 5 degrees higher than the target temperature, the temperature drift correction coefficient is 1.2. The load correction coefficient is obtained by the dynamic correction unit through comparative analysis of the load pressure data and the expected load condition under the target working condition. For example, calculate the difference between the actual load pressure and the target load pressure, and then convert it into the load correction coefficient through a specific algorithm. Suppose the actual load pressure is 100N greater than the target load pressure, and the calculated load correction coefficient is 1.1. The stiffness decay factor is calculated by the dynamic correction unit based on the vibration spectrum data. For example, by analyzing the amplitude and phase and other information of specific frequency components in the vibration spectrum, the stiffness decay factor is obtained. If the vibration spectrum shows that there is strong high-frequency vibration in the guide rail, the calculated stiffness decay factor = 0.8, where the above parameters can all be obtained according to a pre-trained model or a pre-determined mapping relationship.

[0033] This embodiment can achieve dynamic optimization of the thermal deformation compensation amount to better compensate for the deformation of the guide rail caused by various factors.

[0034] In a preferred embodiment, if the piezoelectric ceramic unit is arranged at the micro-deformation sensitive point of the guide rail sliding surface, then the piezoelectric ceramic units are arranged in a honeycomb topology, and the distance between adjacent piezoelectric ceramic units is less than the heat conduction wavelength.

[0035] Specifically, in the design stage, according to the shape and size of the guide rail sliding surface, use computer-aided design (CAD) software to plan the layout of the piezoelectric ceramic units. First, determine the distribution range of the micro-deformation sensitive points, and then arrange the piezoelectric ceramic units at these points in a honeycomb-shaped hexagonal structure with appropriate spacing and angles. For example, on a rectangular guide rail sliding surface, starting from a corner, draw a hexagonal grid with a certain side length, and place the piezoelectric ceramic units at the vertex positions of the grid to ensure that each unit is located at the micro-deformation sensitive point, thus achieving a honeycomb topology layout. Through the material thermal performance test equipment, measure parameters such as the thermal conductivity of the guide rail material, and combine the temperature change situation (such as temperature change frequency, temperature gradient, etc.) during the actual operation of the guide rail, and use the heat conduction theory formula to calculate the heat conduction wavelength. For example, for a certain steel guide rail, knowing its thermal conductivity is λ and the temperature change frequency is f, according to the heat conduction wavelength calculation formula Calculate the heat conduction wavelength of the guide rail under specific working conditions, where is the heat conduction wavelength, is the material density, is the specific heat capacity of the material.

[0036] In this embodiment, a honeycomb topology is adopted to arrange the piezoelectric ceramic units, which can make the compensation effect more uniform and comprehensive on the sliding surface of the guide rail, avoiding compensation blind spots. Since the distribution of micro-deformation sensitive points on the sliding surface of the guide rail is relatively complex, the honeycomb arrangement can better adapt to this distribution characteristic and compensate for the deformation of the guide rail from all directions. And making the distance between adjacent piezoelectric ceramic units less than the heat conduction wavelength is to ensure that the thermal deformation generated by each unit can act independently on the guide rail, avoiding the interference of thermal deformation between adjacent units caused by heat conduction, thereby improving the accuracy and effect of compensation.

[0037] In a preferred embodiment, if the piezoelectric ceramic unit is arranged at the stress concentration point of the moving part, the piezoelectric ceramic unit and the strain gauge are integrally packaged to form a force-electricity coupling feedback link.

[0038] Specifically, the force-electricity coupling feedback link means that the piezoelectric ceramic unit and the strain gauge are integrally packaged together to form a connection method that can realize the mutual conversion and feedback of force and electrical signals. The strain gauge can convert the force it senses into an electrical signal, while the piezoelectric ceramic unit can generate a corresponding deformation (force) according to the received electrical signal. A feedback loop is formed through circuit connection between the two to realize the real-time monitoring and control of the stress state of the moving part. First, select appropriate piezoelectric ceramic units and strain gauges to ensure that their parameters such as size and performance match each other. Then, use micro-packaging technology to closely bond the strain gauge and the piezoelectric ceramic unit together and connect them through wires to form a circuit. During actual installation, install the integrally packaged component at the stress concentration point of the moving part. For example, for the stress concentration point of an aluminum alloy moving part, select a piezoelectric ceramic unit with a size of 5mm×5mm and a compatible foil strain gauge. In a dust-free environment, use a special encapsulation adhesive to paste the strain gauge on the surface of the piezoelectric ceramic unit, and then weld the wires to the electrodes of the two to complete the production of the force-electricity coupling feedback link. Finally, install the component at the stress concentration point of the moving part by mechanical fixing.

[0039] In this embodiment, a force-electricity coupling feedback link is provided at the stress concentration point of the moving part, which can monitor the stress change at the stress concentration point in real time, and timely adjust the stress state of the part through the piezoelectric ceramic unit, so as to reduce the influence of stress concentration on the straightness of the guide rail. When the stress at the stress concentration point changes, the strain gauge will convert this change into an electrical signal and transmit it to the piezoelectric ceramic unit. The piezoelectric ceramic unit generates a corresponding deformation according to the received electrical signal to compensate for the stress of the part, forming a closed-loop automatic adjustment system.

[0040] In a preferred embodiment, if the piezoelectric ceramic unit is arranged at the vibration transfer node of the guide rail foundation support structure, the piezoelectric ceramic unit is connected in parallel with the active damper and switches the compensation mode according to the stiffness attenuation factor; The switching of the compensation mode according to the stiffness attenuation factor includes: If the stiffness attenuation factor is greater than the preset attenuation factor, deformation compensation is performed; If the stiffness attenuation factor is less than or equal to the preset attenuation factor, switch to the vibration energy absorption mode; Wherein, the value range of the preset attenuation factor is between 0.65 and 0.8.

[0041] Specifically, an active damper is a device that can actively generate a force opposite to the vibration direction to suppress vibration. It usually consists of a sensor, a controller and an actuator. The sensor detects the vibration signal, the controller analyzes and calculates the reaction force to be applied according to the signal, and then the actuator generates a corresponding force to cancel the vibration energy. Select a suitable type of active damper according to the characteristics and vibration characteristics of the guide rail foundation support structure. For example, for the guide rail support structure of a large machine tool, its vibration frequency range is between 10-100Hz. According to this frequency range and the required damping force, an electromagnetic active damper that can work effectively in this frequency range and provide sufficient damping force is selected. The preset attenuation factor is determined by experimental testing and simulation analysis of the stiffness change of the guide rail foundation support structure under different working conditions, combined with the allowable range of the straightness error of the guide rail. For example, conduct multiple loading and vibration tests on a certain guide rail foundation support structure, record the straightness error of the guide rail under different stiffness attenuations, and through data analysis, it is found that when the stiffness attenuation factor is between 0.65 and 0.8 (including 0.65 and 0.8), the straightness error of the guide rail begins to exceed the allowable range. Therefore, the preset attenuation factor is set within this range. Optionally, the preset attenuation factor is 0.8.

[0042] This embodiment is based on the principle of real-time monitoring and intelligent control of the vibration and stiffness changes of the guide rail. By monitoring the stiffness attenuation factor, the working state of the guide rail is judged, and then the working modes of the piezoelectric ceramic unit and the active damper are switched according to different states. In the vibration energy absorption mode, the active damper and the piezoelectric ceramic unit work together to convert the vibration energy into other forms of energy (such as heat energy, etc.) for consumption; in the deformation compensation mode, the piezoelectric ceramic unit generates corresponding deformations according to the straightness error to correct the geometric shape of the guide rail.

[0043] In a preferred embodiment, the temperature drift correction coefficient is the product of the temperature base correction coefficient and the weight factor of the temperature base correction coefficient; the dynamic correction unit is further configured to: If the instantaneous temperature change rate of the real-time temperature data and the target temperature sequence exceeds the set threshold, or abnormal harmonic components appear in the vibration spectrum data, then the compensation enhancement mode is triggered; the compensation enhancement mode includes: Dynamically adjust the weight factor of the temperature base correction coefficient based on the temperature mutation direction; Perform an inverse Fourier transform on the abnormal harmonic components to generate a time-domain reverse excitation signal, the signal phase of the time-domain reverse excitation signal is offset by 180°±5°, and the amplitude is 120%-150% of the energy of the abnormal harmonic components; Output the time-domain reverse excitation signal through the distributed piezoelectric ceramic array to cancel the vibration energy.

[0044] Specifically, the instantaneous temperature change rate is obtained through the formula The data is collected by the embedded PT100 temperature sensor at a sampling period of 10 ms and calculated after Kalman filtering. The set threshold is 10°C / s. Based on the thermal expansion coefficient of the guide rail material (such as steel: 11.7×10 -6 / °C), a 10°C / s temperature rise will cause an instantaneous thermal deformation of 0.12 mm / m, exceeding the preset accuracy (±5 μm / m); the abnormal harmonic components are high-frequency harmonic components (500 Hz - 2 kHz) in the vibration spectrum that exceed 3 times the standard deviation of the normal working condition. The detection method is to collect the vibration signal through an acceleration sensor, and after FFT transformation, calculate the spectral mean μ and standard deviation σ of the reference working condition. The abnormal condition is determined as: A harmonic > μ + 3σ; the abnormal harmonics in this frequency band are usually caused by local stiffness mutations or bearing damage of the guide rail and need to be actively suppressed.

[0045] Specifically, the temperature mutation direction is determined by the magnitude of the instantaneous temperature change rate and 0. If the temperature mutation direction is an instantaneous temperature increase (ΔT / Δt > 0), the weight factor α is increased from 1.0 to 1.5 - 2.0 times to strengthen the compensation for thermal expansion. If the temperature mutation direction is an instantaneous temperature decrease (ΔT / Δt < 0), the weight factor α is decreased from 1.0 to 0.5 - 0.8 times to avoid overcompensation. Through dynamic adjustment of the weight, the nonlinear thermal expansion characteristics of the material (such as the increase in the thermal expansion coefficient in the high-temperature region) are matched.

[0046] Specifically, the inverse fast Fourier transform (IFFT) is performed on the abnormal harmonic components to extract the time-domain waveform. The waveform is phase-shifted (180° ± 5°) and amplitude-amplified (120% - 150%), and a reverse excitation signal is output through the piezoelectric ceramic actuator. Exemplarily, when an 800 Hz abnormal harmonic (amplitude 0.5 g) is detected, a reverse signal with a phase shift of 185° and an amplitude of 0.6 g is generated, and the vibration energy attenuation rate ≥ 60%.

[0047] This embodiment can, during the dynamic operation of the guide rail, monitor the mutation signals of temperature and vibration in real time, and through dynamic adjustment of the compensation parameters and reverse vibration excitation, actively suppress the thermal-vibration coupling error and shorten the thermal deformation compensation response time.

[0048] In a preferred embodiment, the compensation module is further configured to: Monitor the working state of the piezoelectric ceramic units at each of the points to be compensated in real time, and determine whether there are any failed points; the failed points are the points to be compensated where the current deviation rate is greater than a first preset threshold and continues to be greater than the first preset duration. Specifically, the working state includes the actual working current of the piezoelectric ceramic unit. The current deviation rate is the percentage deviation of the actual working current from the nominal value. Optionally, the first preset threshold is ±30% (typical values for open / short circuit faults), and the duration ≥ 100 ms (to avoid misjudgment due to instantaneous interference).

[0049] If so, taking the failed point as the center, select the piezoelectric ceramic units at the adjacent points within a first preset radius to form a compensation sub-network. Specifically, the first preset radius is set based on the honeycomb topology arrangement spacing and the heat conduction wavelength (λ = 60 mm) to ensure that adjacent units can cover the failed area, and it can be selected as 50 mm. Taking the failed point as the center, select the adjacent piezoelectric ceramic units with a spacing ≤ 50 mm, and preferably select the honeycomb topology nodes of the same guide rail section to form a compensation sub-network.

[0050] Reallocate the thermal deformation compensation amount corresponding to the failed point into sub-compensation amounts to the compensation sub-network.

[0051] Specifically, it is weighted and distributed in inverse proportion to the distance, and the formula is , where is the distance between adjacent units and the failure point, j is the total number of adjacent units, is the original compensation amount of the failure point, is the compensation amount allocated to the i-th adjacent unit. Exemplarily, if the original compensation amount of the failure point is 0.2 mm and the distances of adjacent units are 10 mm, 20 mm, and 30 mm respectively, the compensation amount distribution is as follows: is 0.109 mm, is 0.055 mm, is 0.036 mm.

[0052] In this embodiment, through current monitoring and compensation network reconstruction, dynamic fault tolerance during the failure of piezoelectric ceramic units is achieved, ensuring the continuous high-precision operation of the system.

[0053] In a preferred embodiment, after determining whether there is a failure point, the compensation module is further configured to: If so, apply a reverse voltage gradient to the piezoelectric ceramic units at the micro-deformation sensitive points to cool down the area of the failure point until the instantaneous temperature change rate of the real-time temperature data and the target temperature sequence is within the set threshold.

[0054] Specifically, the reverse voltage gradient refers to applying a reverse driving voltage (-50 V to -100 V) to the piezoelectric ceramics at the micro-deformation sensitive points to generate the inverse piezoelectric effect. According to the Peltier effect, the reverse voltage causes the piezoelectric ceramic lattice to contract and absorb heat. The amplitude of the reverse voltage is adjusted through the PID algorithm to stabilize the cooling rate at 5 - 8 °C / min until the deviation between the real-time temperature and the target sequence is ≤ ±3 °C. Exemplarily, if the temperature of the failure point rises by 15 °C due to short-circuit heating, the system applies a -80 V reverse voltage, and the temperature drops by 7 °C per minute, and the temperature returns to the set range within 2.14 minutes.

[0055] This embodiment utilizes the inverse piezoelectric effect of piezoelectric ceramics to generate local heat absorption, suppress local temperature rise, and avoid the chain diffusion of thermal errors in the failure point area.

[0056] In this article, specific examples are used to elaborate on the principles and implementation methods of this application. The descriptions of the above embodiments are only used to help understand the method and its core idea of this application. The above are only the preferred implementation methods of this application. It should be noted that due to the limited nature of language expression and objectively infinite specific structures, for those of ordinary skill in the art in this technical field, without departing from the principle of this invention, several improvements, refinements or changes can be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or directly applying the concept and technical solution of the invention to other occasions without improvement, should all be regarded as the protection scope of this application.

Claims

1. A real-time compensation system for guide rail dynamic errors based on multi-sensor fusion, characterized in that: include: A retrieval module (1), the retrieval module (1) being configured to retrieve and traverse a temperature sequence database to obtain a target temperature sequence matching a target operating condition; the temperature sequence database comprising a plurality of groups of historical operating conditions and a historical temperature sequence corresponding to each group of the historical operating conditions, the historical operating conditions comprising a moving speed, an acceleration and a load distribution of a moving part slidably connected to a guide rail, the historical temperature sequence comprising temperatures corresponding to a plurality of points distributed along an extension direction of the guide rail, the target temperature sequence being a historical temperature sequence corresponding to the historical operating condition matching the target operating condition; A prediction module (2), the prediction module (2) being configured to construct a finite element model of the guide rail, and in combination with the target temperature sequence, obtain a predicted straightness sequence of the guide rail in a working state corresponding to the target working condition, and further obtain a straightness error sequence; the predicted straightness sequence includes predicted straightnesses corresponding to a plurality of points, the straightness error sequence includes a plurality of straightness errors, and the straightness error is an absolute value of a difference between the predicted straightness and a preset straightness; A judgment module (3), the judgment module (3) being configured to traverse the straightness error sequence to judge whether there is a straightness error greater than a preset precision in the straightness error sequence; if so, taking a point corresponding to a predicted straightness corresponding to the straightness error greater than the preset precision as a point to be compensated; A compensation module (4), wherein the compensation module (4) is configured to obtain a corresponding thermal deformation compensation amount according to the straightness error corresponding to each of the points to be compensated, and to compensate the straightness error of each of the points to be compensated with the thermal deformation compensation amount during the operation of the guide rail in the target working condition through a distributed piezoelectric ceramic array; the distributed piezoelectric ceramic array is composed of a plurality of piezoelectric ceramic units respectively arranged at each point.

2. The guide rail dynamic error real-time compensation system based on multi-sensor fusion according to claim 1 is characterized in that: The compensation module (4) comprises: A real-time sensing unit, wherein the real-time sensing unit is configured to collect real-time temperature data, load pressure data and vibration spectrum data of each point during the operation of the guide rail under the target working condition; A dynamic correction unit, the dynamic correction unit is configured to perform differential calculation on the real-time temperature data, the load pressure data and the target temperature sequence, generate a temperature drift correction coefficient and a load correction coefficient, and calculate a stiffness attenuation factor according to the vibration spectrum data; An online compensation optimization unit is configured to obtain an updated thermal deformation compensation amount based on a temperature drift correction coefficient, a load correction coefficient, and a stiffness attenuation factor, so that the distributed piezoelectric ceramic array adjusts the thermal deformation compensation amount in real time according to the updated thermal deformation compensation amount.

3. The guide rail dynamic error real-time compensation system based on multi-sensor fusion according to claim 2 is characterized in that: according to Get the updated thermal deformation compensation amount; where, Indicates the amount of thermal deformation compensation after update, Indicates the thermal deformation compensation amount, represents the temperature drift correction coefficient, Indicates the load correction factor, Represents the stiffness reduction factor.

4. The guide rail dynamic error real-time compensation system based on multi-sensor fusion according to claim 1 is characterized in that: The points include microscopic deformation sensitive points of the sliding surface of the guide rail, and / or stress concentration points of the moving parts, and / or vibration transmission nodes of the guide rail foundation support structure.

5. The guide rail dynamic error real-time compensation system based on multi-sensor fusion according to claim 4 is characterized in that: If the piezoelectric ceramic units are disposed at microscopic deformation sensitive points on the sliding surface of the guide rail, the piezoelectric ceramic units are arranged in a honeycomb topology, and the spacing between adjacent piezoelectric ceramic units is smaller than the heat conduction wavelength.

6. The guide rail dynamic error real-time compensation system based on multi-sensor fusion according to claim 4 is characterized in that: If the piezoelectric ceramic unit is disposed at the stress concentration point of the moving component, the piezoelectric ceramic unit is integrated and packaged with the strain gauge to form a force-electric coupling feedback link.

7. The guide rail dynamic error real-time compensation system based on multi-sensor fusion according to claim 4 is characterized in that: If the piezoelectric ceramic unit is provided at the vibration transmission node of the guide rail foundation support structure, the piezoelectric ceramic unit is connected in parallel with the active damper, and the compensation mode is switched according to the stiffness attenuation factor; The switching of the compensation mode according to the stiffness attenuation factor comprises: If the stiffness attenuation factor is greater than the preset attenuation factor, deformation compensation is performed; If the stiffness attenuation factor is less than or equal to the preset attenuation factor, switching to the vibration energy absorption mode; The preset attenuation factor has a value range of 0.65-0.

8.

8. The guide rail dynamic error real-time compensation system based on multi-sensor fusion according to claim 2 is characterized by: The temperature drift correction coefficient is the product of the temperature base correction coefficient and the weight factor of the temperature base correction coefficient; the dynamic correction unit is also configured to: If the instantaneous temperature change rate between the real-time temperature data and the target temperature sequence exceeds a set threshold, or an abnormal harmonic component appears in the vibration spectrum data, the compensation enhancement mode is triggered; The compensation enhancement mode includes: Dynamically adjust the weight factor of the temperature basic correction coefficient based on the direction of temperature mutation; Performing an inverse Fourier transform on the abnormal harmonic component to generate a time-domain reverse excitation signal, wherein the signal phase of the time-domain reverse excitation signal is shifted by 180°±5° and the amplitude is 120%-150% of the energy of the abnormal harmonic component; The time domain reverse excitation signal is outputted through the distributed piezoelectric ceramic array to offset the vibration energy.

9. The guide rail dynamic error real-time compensation system based on multi-sensor fusion according to claim 1, characterized in that: The compensation module (4) is also configured to: Monitor the working state of the piezoelectric ceramic unit at each of the points to be compensated in real time, and determine whether there is a failure point; the failure point is a point to be compensated where the current deviation rate is greater than a first preset threshold and lasts for more than a first preset time; If yes, taking the failure point as the center, piezoelectric ceramic units at adjacent points within a first preset radius are selected to form a compensation sub-network; The thermal deformation compensation amount corresponding to the failure point is reallocated as a sub-compensation amount to the compensation sub-network.

10. The guide rail dynamic error real-time compensation system based on multi-sensor fusion according to claim 9, characterized in that: After determining whether a failure point exists, the compensation module (4) is further configured to: If so, a reverse voltage gradient is applied to the piezoelectric ceramic unit at the microscopic deformation sensitive point to cool down the failure point area until the instantaneous temperature change rate of the real-time temperature data and the target temperature sequence is within the set threshold.

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