Anti-unbalance mechanism of rotary table of numerical control machine tool and detection control method

Abstract

The application discloses a kind of CNC machine tool rotary table mechanism and prevent deviation load detection control method, at least two groups of deviation load prevention mechanisms are evenly spaced around the circumference of the table, and the deviation load detection control method is: calibration P0 and P (1, i) and P (3, i);Calibrate the transfer coefficient of each deviation load prevention mechanism;When the table is stationary, the current pressure value at the position of each sensor is synchronously collected;For each deviation load prevention mechanism, its pressure deviation value is calculated one by one, and the deviation load trend of the table at the place is judged;The oil pressure of two deviation load prevention mechanisms A and B arranged radially opposite is linked to control;Oil pressure linkage compensation.The application has the advantages that: the application takes comprehensive deviation signal e as input, according to the transfer coefficient of the upper and lower oil lines of different deviation load prevention mechanisms, calculates the oil pressure adjustment amount required by different mechanisms and different oil lines according to the equal thrust distribution principle, only needs to calculate and adjust once, can quickly generate accurate correction torque to resist the deviation load torque, and the response is very fast.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tool technology, and in particular to an anti-eccentric loading mechanism and detection and control method for a rotary table of a CNC machine tool. Background Technology

[0002] During machining, rotary tables on CNC machine tools often experience off-center loading due to workpiece asymmetry or clamping eccentricity. This off-center loading causes a slight tilt of the table, reducing machining accuracy and even affecting the relative position of the spindle and workpiece. Most existing table assemblies lack active anti-off-center loading structures. Therefore, a feasible and efficient anti-off-center loading mechanism for CNC machine tool rotary tables, along with detection and control methods, is urgently needed. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a feasible and efficient anti-eccentricity mechanism and detection and control method for a rotary table of a CNC machine tool.

[0004] To solve the above-mentioned technical problems, the present invention provides a method for detecting and controlling off-center load on a CNC machine tool rotary table. At least two sets of off-center load prevention mechanisms are evenly spaced around the circumference of the table. Each set of off-center load prevention mechanisms consists of two off-center load prevention mechanisms arranged radially opposite to each other on the table. Any two off-center load prevention mechanisms arranged radially opposite to each other on the table are labeled as A and B. Each off-center load prevention mechanism is provided with an upper oil passage and a lower oil passage, an upper elastic plate and a lower elastic plate. Oil is introduced into the upper and lower oil passages, which can drive the upper and lower elastic plates to undergo local deformation. The local deformation of the upper and lower elastic plates applies pressure to the upper and lower surfaces of the table, thereby resisting the off-center load tendency of the table. The method for preventing off-center load detection and control includes the following steps: S1. Calibrate P0 and P(1,i) and P(3,i): When the worktable is unloaded and horizontal, the upper and lower oil circuits of all anti-eccentric load mechanisms are synchronously pre-pressurized to the set pressure value P0, so that each upper and lower elastic plate achieves pre-tight contact with the corresponding contact surface of the worktable; and for each anti-eccentric load mechanism, the reference pressure value at each sensor position is collected and recorded by several upper and lower thin-film pressure sensors, generating upper thin-film reference pressure datasets and lower thin-film reference pressure datasets for each anti-eccentric load mechanism; and based on the upper and lower thin-film reference pressure datasets, the upper thin-film reference comprehensive pressure characterization value P(1,i) and lower thin-film reference comprehensive pressure characterization value P(3,i) for the i-th anti-eccentric load mechanism are calculated by a preset algorithm; i represents the total number of anti-eccentric load mechanisms, and i is an even number; S2. Under no-load conditions, calibrate the transmission coefficient η of each anti-eccentricity mechanism. iup and η idown η iupη represents the transmission coefficient of the upper oil circuit of the i-th anti-eccentricity mechanism. idown This represents the transmission coefficient of the lower oil circuit of the i-th anti-eccentricity mechanism; the transmission coefficient represents the pressure exerted by the elastic plate on the worktable when the oil pressure increases by a unit pressure, and the unit is N / MPa; the transmission coefficient can be obtained by calibrating through no-load test pressure increment; The method for calibrating the transmission coefficient is as follows: Under no-load conditions, apply a known test pressure increment ΔPtest to the upper and lower oil circuits of the i-th anti-eccentric load mechanism respectively, and measure the change in pressure deviation value ei at the mechanism Δei. Then the transmission coefficient η = Δei / ΔPtest. S3. During the processing, when the worktable is stationary, the current pressure value at each sensor location is collected in real time and synchronously through several upper and lower thin-film pressure sensors. Among them, a set of upper thin-film pressure dataset P containing several pressure values ​​is obtained at the i-th anti-eccentricity mechanism. up,i ) and a set of thin-film pressure datasets P containing several pressure values. down,i ); S4. For each anti-eccentricity loading mechanism, calculate its pressure deviation value and determine the eccentricity loading trend of the worktable at that location: S41. Using the same preset algorithm as in step S1, for the i-th anti-eccentric loading mechanism, based on the upper thin plate pressure dataset P( up,i ), calculate the first comprehensive pressure characterization value P(u,i) of the upper thin sheet; based on the pressure dataset P( of the lower thin sheet) down,i ), calculate the second comprehensive pressure characterization value P(d,i) of the thin sheet; S42. Subtract the first comprehensive pressure characterization value P(u,i) from the upper thin sheet reference comprehensive pressure characterization value P(1,i) to obtain the first change ΔP(u,i)=P(u,i)-P(1,i); The difference between the second comprehensive pressure characterization value P(d,i) and the lower thin sheet reference comprehensive pressure characterization value P(3,i) is used to obtain the second change ΔP(d,i)=P(d,i)-P(3,i); S43. Define the pressure deviation value of the i-th anti-eccentricity mechanism as e. i e i =ΔP(u,i)-ΔP(d,i); If e i If the value is greater than 0, it is determined that the workbench at the i-th anti-eccentricity mechanism has an upward tilting trend. If e i If the value is 0, then the workbench at the i-th anti-eccentricity mechanism is determined to have a downward trend; S5. Calculate the oil pressure adjustment amount: For the two radially opposite anti-eccentric load mechanisms A and B, perform coordinated control of the oil pressure of A and B: Let e ​​= (e A -e B When |e|≦ε, no oil pressure regulation is performed; when |e|>ε, the oil pressure adjustment amount of mechanisms A and B is calculated. ; When e > ε, mechanism A tilts upwards and mechanism B tilts downwards. Therefore, ΔP(A,up) and ΔP(B,down) are calculated according to the principle of equal thrust distribution: ; ; When e < -ε, mechanism A sinks and mechanism B rises. Therefore, ΔP(A,down) and ΔP(B,up) are calculated according to the principle of equal thrust distribution: ; ; in, ε is a preset threshold; e A This indicates the pressure deviation value of the anti-eccentric loading mechanism A; e B This indicates the pressure deviation value of the anti-eccentric loading mechanism B; ΔP(A,up) represents the oil pressure adjustment amount of the oil circuit on the anti-eccentric load mechanism A; ΔP(A,down) represents the oil pressure adjustment amount of the lower oil circuit of the anti-eccentric load mechanism A; ΔP(B,down) represents the oil pressure adjustment amount of the lower oil circuit of the anti-eccentric load mechanism B; ΔP(B,up) represents the oil pressure adjustment amount of the oil circuit on the anti-eccentric load mechanism B; F need The total corrective force required to eliminate the current off-center loading tendency of the worktable; η Aup This represents the transmission coefficient of the upper oil circuit of the anti-eccentric loading mechanism A; η Adown This represents the transmission coefficient of the lower oil circuit of the anti-eccentric loading mechanism A; η Bdown This represents the transmission coefficient of the lower oil circuit of the anti-eccentric loading mechanism B; η Bup This represents the transmission coefficient of the upper oil circuit of the anti-eccentric loading mechanism B; K f K represents the force-deviation conversion factor. f Used to convert pressure deviation e into the required total corrective force F need It can be determined through mechanical analysis or experimental calibration; the unit is N / MPa. S6. Hydraulic Pressure Linkage Compensation: If anti-eccentricity mechanism A is determined to have an upward trend and mechanism B is determined to have a downward trend, then the oil pressure in the upper oil circuit controlling anti-eccentricity mechanism A increases by ΔP(A,up), and the oil supply pressure in the lower oil circuit controlling mechanism B increases by ΔP(B,down), i.e., P A上 =P0+ΔP(A,up); and P B下 =P0+ΔP(B,down); and P A下 =P B上 =P0; If anti-eccentricity mechanism A is determined to have a downward tendency, and mechanism B is determined to have an upward tendency, then the oil pressure in the lower oil circuit controlling anti-eccentricity mechanism A increases by ΔP(A,down), and the oil supply pressure in the upper oil circuit controlling mechanism B increases by ΔP(B,up), that is: P A下 =P0+ΔP(A,down); and P B上 =P0+ΔP(B,up); and P A上 =P B下 =P0; Where P A上 To prevent the oil supply pressure of the upper oil circuit of the off-center loading mechanism A; P A下 To prevent the oil supply pressure of the lower oil circuit of the off-center loading mechanism A; P B上 To prevent the oil supply pressure of the upper oil circuit of the off-center loading mechanism B; P B下 To prevent the oil supply pressure of the lower oil circuit of the off-center loading mechanism B; Repeat steps S3-S6 until the processing is complete; When the worktable needs to rotate, control the upper and lower oil pressure relief of all anti-eccentric load mechanisms to prevent the upper and lower elastic plates from deforming and maintain a preset rotation gap with the worktable.

[0005] Furthermore, after step S4 and before step S5, the system also includes verification of the off-center load trend determination result, including the following steps: Off-center load trend verification of opposing mechanisms: cross-verification is performed based on the off-center load trend determination results of two radially opposite anti-off-center load mechanisms A and B. If the off-center load mechanisms A and B have opposite trends, the trend verification is passed; if the off-center load mechanisms A and B have the same trend, the system issues an "abnormal trend" alarm signal, and the system controls the pressure of all oil circuits of all anti-off-center load mechanisms to P0.

[0006] Furthermore, after the off-center loading trend verification of the opposing mechanism is completed, the amplitude and value are also verified: Let S=e A +e B e A and e B This represents the pressure deviation at points A and B, two radially opposite anti-eccentricity loading mechanisms; if |S| If δ is true, the amplitude and verification are passed; if |S|≧δ, the system issues a "sensor consistency abnormality" alarm signal; the system controls the pressure of all oil circuits of all anti-eccentric load mechanisms to P0; where δ is a preset threshold.

[0007] Furthermore, after the amplitude and verification are completed, circumferential continuity verification is also performed: for three adjacent anti-eccentric load mechanisms: if the trends of the two side mechanisms are the same and the trend of the middle mechanism is opposite to that of the two side mechanisms, the system issues an "abnormal trend oscillation" alarm signal, and the system controls the pressure of all oil circuits of all anti-eccentric load mechanisms to P0.

[0008] Furthermore, the preset algorithm in step S1 is an arithmetic mean or a weighted average.

[0009] Furthermore, after performing step S6, step S7, feedback correction, is performed: the comprehensive deviation signal e after the oil pressure adjustment amount after step S5 is collected in real time. new =(e A’ -e B’ ) / 2; when |e new When |≦λ, no oil pressure regulation is performed; when |e new When |>λ, a closed-loop control model is adopted, allowing e to... new Approaching 0, calculate the common hydraulic pressure correction ΔP for anti-eccentric loading mechanisms A and B. 修 The closed-loop control model includes, but is not limited to, one or more of PID control, fuzzy control, adaptive control, or sliding mode control. When e > λ, anti-eccentricity mechanism A is determined to have an upward tendency, and mechanism B is determined to have a downward tendency. Therefore, the oil pressure in the upper oil circuit of anti-eccentricity mechanism A and the lower oil circuit of mechanism B both increase by ΔP. 修 That is, P A上修 =P A上 +|ΔP 修 |;P B下修 =P B下 +|ΔP 修 |; When e -λ, if anti-eccentricity mechanism A is determined to have a downward tendency and mechanism B is determined to have an upward tendency, then the oil pressure in the lower oil circuit of anti-eccentricity mechanism A and the upper oil circuit of mechanism B both increase by ΔP. 修 That is, P A下修 =P A下 +|ΔP 修 |;P B上修 =P B上 +|ΔP 修 |; λ is a preset threshold; e A’The pressure deviation value of the anti-eccentric load mechanism A after the hydraulic linkage compensation in step S6; e B’ The pressure deviation value of the anti-eccentric load mechanism B after the hydraulic linkage compensation in step S6; P A上修 The upper oil circuit pressure of the anti-eccentric load mechanism A after feedback correction in step S7; P A下修 The lower oil circuit pressure of the anti-eccentric load mechanism A after feedback correction in step S7; P B上修 The upper oil circuit pressure of the anti-eccentric load mechanism B after feedback correction in step S7; P B下修 The lower oil circuit pressure of the anti-eccentric load mechanism B after feedback correction in step S7; P A上 The oil supply pressure of the upper oil circuit of the anti-eccentric load mechanism A after the oil pressure linkage compensation in step S6; P A下 The oil supply pressure of the lower oil circuit of the anti-eccentric load mechanism A after the oil pressure linkage compensation in step S6; P B上 The oil supply pressure of the upper oil circuit of the anti-eccentric load mechanism B after the oil pressure linkage compensation in step S6; P B下 The oil supply pressure of the lower oil circuit of the anti-eccentric load mechanism B after the oil pressure linkage compensation in step S6; Repeat steps S3-S7 until the processing is complete.

[0010] This invention provides an anti-eccentricity mechanism for a CNC machine tool rotary table, comprising a base, one side of which has a U-shaped slot; an upper elastic plate is installed on the upper side wall of the slot; a lower elastic plate is installed on the lower side wall of the slot; an upper oil passage and a lower oil passage are provided on the base; a plurality of upper receiving cavities are provided on the upper side of the slot, which are interconnected by upper oil passages, and one end of the upper oil passage extends into one of the upper receiving cavities; a plurality of lower receiving cavities are provided on the lower side of the slot, which are interconnected by lower oil passages, and one end of the lower oil passage extends into one of the lower receiving cavities; a plurality of upper thin-film pressure sensors are installed between the upper elastic plate and the base; a plurality of lower thin-film pressure sensors are installed between the lower elastic plate and the base; both the upper and lower oil passages are connected to an oil supply system.

[0011] Furthermore, the upper and lower elastic sheets are glued to the base using adhesive.

[0012] Furthermore, both the upper elastic sheet and the lower elastic sheet are elastically deformable metal sheets.

[0013] Furthermore, the base includes an upper seat and a lower seat, with the upper oil passage located in the upper seat and the lower oil passage located in the lower seat; the upper seat and the lower seat are connected by a number of screws; the upper seat and the lower seat are assembled to form the "U"-shaped groove.

[0014] Furthermore, a pad is installed between the upper seat and the lower seat.

[0015] Furthermore, the upper receiving cavity and the lower receiving cavity are respectively a plurality of countersunk holes or grooves arranged at intervals along the length of the groove opening.

[0016] Furthermore, the upper thin-film pressure sensor and the lower thin-film pressure sensor are distributed at equal intervals along the length of the slot.

[0017] Beneficial effects of this invention: (1) For continuous cutting and relatively stable load machining processes, under stable hydraulic system temperature and without severe disturbances, the transmission coefficients of the upper and lower oil circuits of each anti-eccentric load mechanism will not change significantly during a single machining process. Therefore, this invention uses the comprehensive deviation signal e as input and calculates the required oil pressure adjustment for different mechanisms and oil circuits according to the calibrated transmission coefficients of the upper and lower oil circuits of different anti-eccentric load mechanisms, based on the principle of equal thrust distribution. This control method only requires one calculation and one adjustment to quickly generate an accurate corrective torque to resist the eccentric load torque, and the response is very rapid. Compared with closed-loop feedback control that requires continuous iterative adjustment, this open-loop control scheme avoids integral delay and possible overshoot oscillation, has a simpler structure, and is more direct in control.

[0018] (2) After the open-loop unequal pressure control based on the transfer coefficient, the introduction of closed-loop feedback correction can effectively cope with the dynamic drift of the transfer coefficient caused by changes in working conditions and temperature fluctuations during the processing. The open-loop control quickly eliminates the main off-center load, and the closed-loop feedback accurately compensates for the residual error. The two work together to ensure the response speed and achieve high-precision steady-state control, which significantly improves the robustness of the system and the processing accuracy.

[0019] (3) By combining the trend verification, amplitude verification and circumferential continuity verification of the two radially opposite anti-offset load mechanisms A and B, sensor faults or system anomalies can be detected in time to avoid false compensation; the control logic is reliable and has self-diagnostic capabilities.

[0020] (4) By setting upper and lower elastic plates and discrete receiving cavities in the U-shaped groove of the base, the elastic plates are locally deformed by high-pressure oil. The corrective force can be applied to the worktable in a very short response time (millisecond level) to counteract the off-center loading tendency of the worktable. The structure is compact, the response is fast, the off-center loading is sensitive, and the anti-interference is strong. Moreover, the upper and lower elastic plates can be restored to their original shape by depressurizing the upper and lower oil circuits at the same time, without affecting the normal rotation of the worktable. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of Example 1; Figure 2 for Figure 1 The front view; Figure 3 for Figure 2 AA section view; Figure 4 This is a schematic diagram of the overall structure after removing the upper and lower elastic sheets in Example 1; Figure 5 This is a schematic diagram of the overall structure from another angle after removing the upper and lower elastic plates in Example 1. Figure 6 This is a schematic diagram of the overall structure from another angle after removing the upper and lower elastic plates in Example 1.

[0022] In the diagram, 1-lower seat, 2-upper seat, 3-upper elastic plate, 4-lower elastic plate, 5-upper receiving cavity, 6-lower receiving cavity, 7-upper oil passage, 8-lower oil passage, 9-pad, 10-upper oil passage, 11-lower oil passage, 12-upper diaphragm pressure sensor, 13-lower diaphragm pressure sensor. Detailed Implementation

[0023] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] Example 1 A mechanism for preventing off-center loading on a CNC machine tool rotary table, such as Figure 1-6As shown, the system includes a base with a U-shaped groove on one side. An upper elastic plate 3 is installed on the upper side wall of the groove, and a lower elastic plate 4 is installed on the lower side wall. An upper oil passage 7 and a lower oil passage 8 are provided on the base. Several upper receiving cavities 5 are provided on the upper side of the groove, and the upper receiving cavities 5 are interconnected through upper oil passages 10. One end of the upper oil passage 7 extends into one of the upper receiving cavities 5. Several lower receiving cavities 6 are provided on the lower side of the groove, and the lower receiving cavities 6 are interconnected through lower oil passages 11. One end of the lower oil passage 8 extends into one of the lower receiving cavities 6. Several upper thin-film pressure sensors 12 are installed between the upper elastic plate 3 and the base. Several lower thin-film pressure sensors 13 are installed between the lower elastic plate 4 and the base. Both the upper oil passage 7 and the lower oil passage 8 are connected to the oil supply system.

[0025] Specifically, to prevent oil leakage from the gap between the elastic sheet and the base, the upper elastic sheet 3 and the lower elastic sheet 4 are glued to the base with adhesive. The elastic sheet and the base are glued together around the entire perimeter of the upper receiving cavity 5 and the lower receiving cavity 6.

[0026] After the oil enters the upper receiving cavity 5 and the lower receiving cavity 6 from the upper oil passage 7 and the lower oil passage 8 respectively, it squeezes the parts of the upper elastic plate 3 and the lower elastic plate 4 that correspond to the positions of the upper receiving cavity 5 and the lower receiving cavity 6. The parts of the upper elastic plate 3 and the lower elastic plate 4 undergo elastic deformation and come into contact with the surface of the worktable, thus applying pressure to the worktable.

[0027] Specifically, both the upper elastic sheet 3 and the lower elastic sheet 4 are elastically deformable thin metal sheets.

[0028] Specifically, the upper receiving cavity 5 and the lower receiving cavity 6 are several countersunk holes or grooves arranged at intervals along the length of the groove opening.

[0029] Specifically, the upper thin-film pressure sensor 12 and the lower thin-film pressure sensor 13 are distributed at equal intervals along the length of the slot.

[0030] Specifically, the base includes an upper seat 2 and a lower seat 1. An upper oil passage 7 is located within the upper seat 2, and a lower oil passage 8 is located within the lower seat 1. The upper seat 2 and lower seat 1 are connected by several screws. The upper seat 2 and lower seat 1, when combined, form a U-shaped groove. A pad 9 is also installed between the upper seat 2 and lower seat 1. When installing the anti-eccentricity mechanism, the installation accuracy of the anti-eccentricity mechanism can be adjusted by grinding the pad 9 on-site. Compared to setting the base as a single unit, this method is more convenient for installation and adjustment.

[0031] When the worktable needs to rotate, the oil supply system depressurizes the upper oil circuit 7 and the lower oil circuit 8, ensuring that the upper elastic plate 3 and the lower elastic plate 4 remain undeformed. A preset rotational clearance is maintained between the upper and lower elastic plates 3 and 4 and the surface of the worktable, preventing interference with the rotation. When the worktable is stationary and in processing mode, if an off-center load occurs, the upper diaphragm pressure sensor 12 and the lower diaphragm pressure sensor 13 can detect the pressure in real time. The detected pressure is calculated, and if a preset condition is met, it can be determined whether the worktable has an upward or downward tendency. If an upward tendency is detected, oil is added to the upper oil circuit 7 to increase the oil pressure. Under this pressure, the upper elastic plate 3 undergoes elastic deformation, applying a downward force to the top of the worktable to suppress the upward tendency. If a downward trend is detected, oil is added to the lower oil passage 8 to increase its oil pressure. Under the action of the oil pressure, the lower elastic plate 4 undergoes elastic deformation, and the lower elastic plate 4 applies an upward force to the top of the worktable to suppress the downward trend of the worktable.

[0032] Example 2 A method for detecting and controlling off-center load on a CNC machine tool rotary table includes at least two sets of off-center load prevention mechanisms evenly spaced around the circumference of the table. Each set of off-center load prevention mechanisms consists of two off-center load prevention mechanisms arranged radially opposite to each other on the table. Any two off-center load prevention mechanisms arranged radially opposite to each other on the table are labeled as A and B. Each off-center load prevention mechanism is equipped with an upper oil passage 7 and a lower oil passage 8, an upper elastic plate 3 and a lower elastic plate 4. Oil is introduced into the upper oil passage 7 and the lower oil passage 8, which can drive the upper elastic plate 3 and the lower elastic plate 4 to undergo local deformation. The local deformation of the upper elastic plate 3 and the lower elastic plate 4 applies pressure to the upper and lower surfaces of the table, thereby resisting the off-center load tendency of the table. The method for preventing off-center load detection and control includes the following steps: S1. Calibrate P0 and P(1,i) and P(3,i): When the worktable is unloaded and horizontal, the upper oil circuit 7 and lower oil circuit 8 of all anti-eccentric load mechanisms are synchronously pre-pressurized to the set pressure value P0, so that each upper elastic plate 3 and each lower elastic plate 4 achieves pre-tight contact with the corresponding contact surface of the worktable; and for each anti-eccentric load mechanism, the reference pressure value at each sensor position is collected and recorded by several upper thin film pressure sensors 12 and several lower thin film pressure sensors 13, respectively generating upper thin film reference pressure dataset and lower thin film reference pressure dataset for each anti-eccentric load mechanism; and according to the upper thin film reference pressure dataset and lower thin film reference pressure dataset, the upper thin film reference comprehensive pressure characterization value P(1,i) and lower thin film reference comprehensive pressure characterization value P(3,i) for the i-th anti-eccentric load mechanism are calculated by a preset algorithm; i represents the total number of anti-eccentric load mechanisms, and i is an even number; P0, P(1,i), and P(3,i) were determined through calibration experiments under no-load conditions on the worktable and are related to the material, thickness, and cavity structure of the elastic sheet. Under preload conditions, P0 should be set to allow the elastic sheet to deform and preload the worktable. After long working hours or after replacing the elastic sheet, P0, P(1,i), and P(3,i) need to be recalibrated.

[0033] S2. Under no-load conditions, calibrate the transmission coefficient η of each anti-eccentricity mechanism. iup and η idown η iup η represents the transmission coefficient of the upper oil circuit of the i-th anti-eccentricity mechanism. idown This represents the transmission coefficient of the lower oil circuit of the i-th anti-eccentricity mechanism; the transmission coefficient represents the pressure exerted by the elastic plate on the worktable when the oil pressure increases by a unit pressure, and the unit is N / MPa; the transmission coefficient can be obtained by calibrating through no-load test pressure increment; The method for calibrating the transmission coefficient is as follows: Under no-load conditions, apply a known test pressure increment ΔPtest to the upper and lower oil circuits of the i-th anti-eccentric load mechanism respectively, and measure the change in pressure deviation value ei at the mechanism Δei. Then the transmission coefficient η = Δei / ΔPtest. The calibration work in S1 and S2 can be performed before each processing step; S3. During the processing, when the worktable is stationary, the current pressure value at each sensor location is collected in real time and synchronously by several upper thin-film pressure sensors 12 and several lower thin-film pressure sensors 13. Among them, a set of upper thin-film pressure dataset P containing several pressure values ​​is obtained at the i-th anti-eccentricity mechanism. up,i ) and a set of thin-film pressure datasets P containing several pressure values. down,i ); S4. For each anti-eccentricity loading mechanism, calculate its pressure deviation value and determine the eccentricity loading trend of the worktable at that location: S41. Using the same preset algorithm as in step S1, for the i-th anti-eccentric loading mechanism, based on the upper thin plate pressure dataset P( up,i ), calculate the first comprehensive pressure characterization value P(u,i) of the upper thin sheet; based on the pressure dataset P( of the lower thin sheet) down,i ), calculate the second comprehensive pressure characterization value P(d,i) of the thin sheet; S42. Subtract the first comprehensive pressure characterization value P(u,i) from the upper thin sheet reference comprehensive pressure characterization value P(1,i) to obtain the first change ΔP(u,i)=P(u,i)-P(1,i); The difference between the second comprehensive pressure characterization value P(d,i) and the lower thin sheet reference comprehensive pressure characterization value P(3,i) is used to obtain the second change ΔP(d,i)=P(d,i)-P(3,i); S43. Define the pressure deviation value of the i-th anti-eccentricity mechanism as e. i e i =ΔP(u,i)-ΔP(d,i); If e i If the value is greater than 0, it is determined that the workbench at the i-th anti-eccentricity mechanism has an upward tilting trend. If e i If the value is 0, then the workbench at the i-th anti-eccentricity mechanism is determined to have a downward trend; S5. Calculate the oil pressure adjustment amount: For the two radially opposite anti-eccentric load mechanisms A and B, perform coordinated control of the oil pressure of A and B: Let e ​​= (e A -e B When |e|≦ε, no oil pressure regulation is performed; when |e|>ε, the oil pressure adjustment amount of mechanisms A and B is calculated. ; When e > ε, mechanism A tilts upwards and mechanism B tilts downwards. Therefore, ΔP(A,up) and ΔP(B,down) are calculated according to the principle of equal thrust distribution: ; ; When e < -ε, mechanism A sinks and mechanism B rises. Therefore, ΔP(A,down) and ΔP(B,up) are calculated according to the principle of equal thrust distribution: ; ; in, ε is a preset threshold; the value of ε ranges from 0.01 to 0.03 MPa. e A This indicates the pressure deviation value of the anti-eccentric loading mechanism A; e B This indicates the pressure deviation value of the anti-eccentric loading mechanism B; ΔP(A,up) represents the oil pressure adjustment amount of the oil circuit on the anti-eccentric load mechanism A; ΔP(A,down) represents the oil pressure adjustment amount of the lower oil circuit of the anti-eccentric load mechanism A; ΔP(B,down) represents the oil pressure adjustment amount of the lower oil circuit of the anti-eccentric load mechanism B; ΔP(B,up) represents the oil pressure adjustment amount of the oil circuit on the anti-eccentric load mechanism B; F need The total corrective force required to eliminate the current off-center loading tendency of the worktable; η Aup This represents the transmission coefficient of the upper oil circuit of the anti-eccentric loading mechanism A; η Adown This represents the transmission coefficient of the lower oil circuit of the anti-eccentric loading mechanism A; η Bdown This represents the transmission coefficient of the lower oil circuit of the anti-eccentric loading mechanism B; η Bup This represents the transmission coefficient of the upper oil circuit of the anti-eccentric loading mechanism B; K f K represents the force-deviation conversion factor. f Used to convert pressure deviation e into the required total corrective force F need It can be determined through mechanical analysis or experimental calibration; the unit is N / MPa. S6. Hydraulic Pressure Linkage Compensation: If anti-eccentric load mechanism A is determined to have an upward trend and mechanism B is determined to have a downward trend, then the hydraulic pressure in the upper hydraulic circuit 7 controlling anti-eccentric load mechanism A increases by ΔP(A,up), and the oil supply pressure in the lower hydraulic circuit 8 controlling mechanism B increases by ΔP(B,down), i.e., P A上 =P0+ΔP(A,up); and P B下 =P0+ΔP(B,down); and P A下 =P B上 =P0; If anti-eccentricity mechanism A is determined to have a downward trend and mechanism B is determined to have an upward trend, then the oil pressure in the lower oil circuit 8 controlling anti-eccentricity mechanism A increases by ΔP(A,down), and the oil supply pressure in the upper oil circuit 7 controlling mechanism B increases by ΔP(B,up), that is: P A下 =P0+ΔP(A,down); and P B上 =P0+ΔP(B,up); and P A上 =P B下 =P0; Where P A上 To prevent the oil supply pressure of the upper oil circuit 7 of the off-center loading mechanism A; P A下 To prevent the oil supply pressure of the lower oil circuit 8 of the off-center loading mechanism A; P B上 To prevent the oil supply pressure of the upper oil circuit 7 of the off-center loading mechanism B; P B下 To prevent the oil supply pressure of the lower oil circuit 8 of the off-center loading mechanism B; Repeat steps S3-S6 until the processing is complete; When the worktable needs to rotate, the upper oil circuit 7 and lower oil circuit 8 of all anti-eccentric load mechanisms are depressurized to prevent the upper elastic plate 3 and lower elastic plate 4 from deforming and to maintain a preset rotation gap with the worktable; in this embodiment, the preset rotation gap is 0.03mm to 0.08mm.

[0034] For continuous cutting processes with relatively stable loads, under conditions of stable hydraulic system temperature and no severe disturbances, the transmission coefficients of the upper and lower oil circuits of each anti-eccentricity mechanism will not change significantly during a single machining operation. Therefore, this invention uses the comprehensive deviation signal e as input and calculates the required oil pressure adjustment for different mechanisms and oil circuits according to the calibrated transmission coefficients of the upper and lower oil circuits of different anti-eccentricity mechanisms, following the principle of equal thrust distribution. This control method requires only one calculation and one adjustment to quickly generate an accurate corrective torque to resist the eccentricity torque, exhibiting a very rapid response. Compared with closed-loop feedback control that requires continuous iterative adjustment, this open-loop control scheme avoids integral delay and possible overshoot oscillations, resulting in a simpler structure and more direct control.

[0035] Furthermore, after step S4 and before step S5, the system also includes verification of the off-center load trend determination result, including the following steps: Off-center load trend verification of opposing mechanisms: cross-verification is performed based on the off-center load trend determination results of two radially opposite anti-off-center load mechanisms A and B. If the off-center load mechanisms A and B have opposite trends, the trend verification is passed; if the off-center load mechanisms A and B have the same trend, the system issues an "abnormal trend" alarm signal, and the system controls the pressure of all oil circuits of all anti-off-center load mechanisms to P0.

[0036] Furthermore, after the off-center loading trend verification of the opposing mechanism is completed, the amplitude and value are also verified: Let S=e A +e B e A and e B This represents the pressure deviation at points A and B, two radially opposite anti-eccentricity loading mechanisms; if |S| If δ is true, the amplitude and verification are passed; if |S|≧δ, the system issues a "sensor consistency abnormality" alarm signal; the system controls the pressure of all oil circuits of all anti-eccentric load mechanisms to P0; where δ is a preset threshold.

[0037] Furthermore, after the amplitude and verification are completed, circumferential continuity verification is also performed: for three adjacent anti-eccentric load mechanisms: if the trends of the two side mechanisms are the same and the trend of the middle mechanism is opposite to that of the two side mechanisms, the system issues an "abnormal trend oscillation" alarm signal, and the system controls the pressure of all oil circuits of all anti-eccentric load mechanisms to P0.

[0038] By combining three verification methods—trend verification, amplitude verification, and circumferential continuity verification—two radially opposite anti-offset load mechanisms A and B, sensor faults or system anomalies can be detected in a timely manner, avoiding false compensation; the control logic is reliable and has self-diagnostic capabilities.

[0039] Furthermore, the preset algorithm in step S1 is an arithmetic mean or a weighted average.

[0040] Furthermore, after performing step S6, step S7, feedback correction, is performed: the comprehensive deviation signal e after the oil pressure adjustment amount after step S5 is collected in real time. new =(e A’ -e B’ ) / 2; when |e new When |≦λ, no oil pressure regulation is performed; when |e new When |>λ, a closed-loop control model is adopted, allowing e to... new Approaching 0, calculate the common hydraulic pressure correction ΔP for anti-eccentric loading mechanisms A and B. 修 The closed-loop control model includes, but is not limited to, one or more of PID control, fuzzy control, adaptive control, or sliding mode control. When e > λ, anti-eccentricity mechanism A is determined to have an upward tendency, and mechanism B is determined to have a downward tendency. Therefore, the oil pressure in the upper oil passage 7 of anti-eccentricity mechanism A and the lower oil passage 8 of mechanism B both increase by ΔP. 修 That is, P A上修 =P A上 +|ΔP 修 |;P B下修 =P B下 +|ΔP 修 |; When e If anti-eccentricity mechanism A is determined to have a downward tendency and mechanism B is determined to have an upward tendency, then the oil pressure in the lower oil passage 8 of anti-eccentricity mechanism A and the upper oil passage 7 of mechanism B will both increase by ΔP. 修 That is, P A下修 =P A下 +|ΔP 修 |;P B上修 =P B上 +|ΔP 修 |; λ is a preset threshold; in this embodiment, λ takes a value of 0.001-0.005 MPa. e A’ The pressure deviation value of the anti-eccentric load mechanism A after the hydraulic linkage compensation in step S6; e B’ The pressure deviation value of the anti-eccentric load mechanism B after the hydraulic linkage compensation in step S6; P A上修 The upper oil circuit pressure of the anti-eccentric load mechanism A after feedback correction in step S7; P A下修 The lower oil circuit pressure of the anti-eccentric load mechanism A after feedback correction in step S7; P B上修 The upper oil circuit pressure of the anti-eccentric load mechanism B after feedback correction in step S7; P B下修The lower oil circuit pressure of the anti-eccentric load mechanism B after feedback correction in step S7; P A上 The oil supply pressure of the upper oil circuit 7 of the anti-eccentric load mechanism A after the oil pressure linkage compensation in step S6; P A下 The oil supply pressure of the lower oil circuit 7 of the anti-eccentric load mechanism A after the oil pressure linkage compensation in step S6; P B上 The oil supply pressure of the upper oil circuit 7 of the anti-eccentric load mechanism B after the oil pressure linkage compensation in step S6; P B下 The oil supply pressure of the lower oil circuit 7 of the anti-eccentric load mechanism B after the oil pressure linkage compensation in step S6; Repeat steps S3-S7 until the processing is complete.

[0041] Based on open-loop unequal pressure control using the transfer coefficient, this invention considers that changes in operating conditions and temperature fluctuations during processing may cause dynamic drift in the transfer coefficient, making it difficult to completely eliminate residual off-center loads using only open-loop control. Therefore, after each open-loop control step, this invention further determines whether closed-loop feedback correction is needed. When preset conditions are met, closed-loop feedback control is activated to precisely compensate for residual off-center loads, thereby effectively eliminating dynamic residuals and ensuring the worktable maintains a high level of precision over the long term.

[0042] In this embodiment, the closed-loop control model employs PID control. PID control is a mature and readily available closed-loop control method.

[0043] ; in: ΔP 修 (t) represents the common oil pressure correction (in MPa). A positive value indicates that the pressure needs to be increased, and a negative value indicates that the pressure needs to be decreased. e new (t) represents the comprehensive deviation signal (unit MPa) at time t after the oil pressure adjustment amount after step S5; K p K i K d To control the gain, the specific value can be determined through debugging.

[0044] K p The proportional gain (dimensionless) determines the system response speed; K i Integral gain (unit: s) -1 This is used to eliminate steady-state errors caused by static off-center loading. K d It represents the differential gain (in seconds), which improves the dynamic stability of the system and suppresses overshoot.

[0045] Working principle of the invention: At least two sets of radially opposite anti-eccentricity mechanisms are arranged around the worktable, and all anti-eccentricity mechanisms are equally spaced. Let A and B represent one set of radially opposite anti-eccentricity mechanisms. When the worktable needs to rotate, the oil supply system depressurizes the upper oil passage 7 and lower oil passage 8 of all anti-eccentricity mechanisms, so that the upper elastic plate 3 and lower elastic plate 4 are in an undeformed state, and a preset rotation gap is left between the upper elastic plate 3 and lower elastic plate 4 and the surface of the worktable, so as not to interfere with the rotation of the worktable.

[0046] Since the worktable is a rigid body, the off-center loading trends of the two radially opposite anti-off-center loading mechanisms A and B are necessarily opposite. When the worktable is stationary and in the processing state, the upper thin-film pressure sensor 12 and the lower thin-film pressure sensor 13 can detect the pressure in real time for each anti-off-center loading mechanism. The detected pressure is calculated, and if a preset condition is met, it can be determined whether the worktable at that point has an upward or downward tendency. Thus, the off-center loading trend is judged for each anti-off-center loading mechanism one by one. Then, by combining the trend verification, amplitude verification, and circumferential continuity verification of the two radially opposite anti-off-center loading mechanisms A and B, sensor failures or system anomalies can be detected in time, avoiding false compensation. When all three verification methods pass, the two radially opposite anti-off-center loading mechanisms A and B are linked and controlled. Taking the comprehensive deviation signal e as input, the required oil pressure adjustment for different mechanisms and different oil circuits is calculated according to the transmission coefficients calibrated for the upper and lower oil circuits of different anti-off-center loading mechanisms, based on the principle of equal thrust distribution. If anti-eccentricity mechanism A is determined to have an upward trend and mechanism B is determined to have a downward trend, then the oil pressure in the upper oil circuit 7 controlling anti-eccentricity mechanism A increases by ΔP(A,up), and the oil supply pressure in the lower oil circuit 8 controlling mechanism B increases by ΔP(B,down), that is: P A上 =P0+ΔP(A,up); and P B下 =P0+ΔP(B,down); and P A下 =P B上 =P0; If anti-eccentricity mechanism A is determined to have a downward tendency and mechanism B is determined to have an upward tendency, then the oil pressure in the lower oil circuit controlling anti-eccentricity mechanism A increases by ΔP(A,down), and the oil supply pressure in the upper oil circuit 7 controlling mechanism B increases by ΔP(B,up), that is: P A下 =P0+ΔP(A,down); and P B上 =P0+ΔP(B,up); and P A上 =P B下 =P0. This control method requires only one calculation and one adjustment to quickly generate an accurate corrective torque to counteract the eccentric load torque, with a very rapid response.

[0047] After each open-loop unequal-pressure control based on the transmission coefficient, e after coordinated control is calculated by introducing closed-loop feedback correction. new and e new In the input closed-loop control model, let e new Approaching 0, the common oil pressure correction ΔP for A and B is calculated. 修 If, after linkage control, anti-eccentric load mechanism A is determined to have an upward trend and mechanism B is determined to have a downward trend, then the oil supply pressure of the upper oil circuit of anti-eccentric load mechanism A and the lower oil circuit of mechanism B will increase synchronously by ΔP. 修 If anti-eccentricity mechanism A is determined to have a downward tendency and mechanism B is determined to have an upward tendency, then the oil supply pressure of the lower oil circuit of anti-eccentricity mechanism A and the upper oil circuit of mechanism B will increase synchronously by ΔP. 修 Following open-loop unequal-pressure control based on the transfer coefficient, the introduction of closed-loop feedback correction effectively addresses the dynamic drift of the transfer coefficient caused by changes in operating conditions and temperature fluctuations during processing. Open-loop control quickly eliminates the main off-center load, while closed-loop feedback precisely compensates for residual errors. The two work together to ensure both rapid response and high-precision steady-state control, significantly improving the system's robustness and processing accuracy.

[0048] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for detecting and controlling off-center load on a rotary table of a CNC machine tool, characterized in that, At least two sets of anti-eccentric load mechanisms are evenly spaced around the circumference of the worktable. Each set of anti-eccentric load mechanisms consists of two anti-eccentric load mechanisms arranged radially opposite to each other on the worktable. Any two anti-eccentric load mechanisms arranged radially opposite to each other on the worktable are marked as A and B. Each anti-eccentric load mechanism is provided with an upper oil passage (7) and a lower oil passage (8), an upper elastic plate (3) and a lower elastic plate (4). Oil is introduced into the upper oil passage (7) and the lower oil passage (8), which can drive the upper elastic plate (3) and the lower elastic plate (4) to undergo local deformation. The local deformation of the upper elastic plate (3) and the lower elastic plate (4) applies pressure to the upper and lower surfaces of the worktable, thereby resisting the eccentric load tendency of the worktable. The method for preventing off-center load detection and control includes the following steps: S1. Calibrate P0 and P(1,i) and P(3,i): When the worktable is unloaded and horizontal, the upper oil circuit (7) and lower oil circuit (8) of all anti-eccentric load mechanisms are synchronously pre-pressurized to the set pressure value P0, so that each upper elastic plate (3) and each lower elastic plate (4) achieves pre-tight contact with the corresponding contact surface of the worktable; and for each anti-eccentric load mechanism, the reference pressure value at each sensor position is collected and recorded by several upper thin film pressure sensors (12) and several lower thin film pressure sensors (13), and the upper thin film reference pressure dataset and lower thin film reference pressure dataset at each anti-eccentric load mechanism are generated respectively; and according to the upper thin film reference pressure dataset and lower thin film reference pressure dataset, the upper thin film reference comprehensive pressure characterization value P(1,i) and lower thin film reference comprehensive pressure characterization value P(3,i) at the i-th anti-eccentric load mechanism are calculated by a preset algorithm; i represents the total number of anti-eccentricity mechanisms, and i is an even number; S2. Under no-load conditions, calibrate the transmission coefficient η of each anti-eccentricity mechanism. iup and η idown η iup η represents the transmission coefficient of the upper oil circuit of the i-th anti-eccentricity mechanism. idown The transmission coefficient of the lower oil circuit of the i-th anti-eccentric load mechanism is represented; the transmission coefficient represents the pressure exerted by the elastic plate on the worktable when the oil pressure increases by a unit pressure. S3. During the processing, when the worktable is stationary, the current pressure value at each sensor position is collected in real time and synchronously through several upper thin-film pressure sensors (12) and several lower thin-film pressure sensors (13). Among them, a set of upper thin-film pressure dataset P containing several pressure values ​​is obtained at the i-th anti-eccentric loading mechanism. up,i ) and a set of thin-film pressure datasets P containing several pressure values. down,i ); S4. For each anti-eccentricity loading mechanism, calculate its pressure deviation value and determine the eccentricity loading trend of the worktable at that location: S41. Using the same preset algorithm as in step S1, for the i-th anti-eccentric loading mechanism, based on the upper thin plate pressure dataset P( up,i ), calculate the first comprehensive pressure characterization value P(u,i) of the upper thin sheet; based on the pressure dataset P( of the lower thin sheet) down,i ), calculate the second comprehensive pressure characterization value P(d,i) of the thin sheet; S42. Subtract the first comprehensive pressure characterization value P(u,i) from the upper thin sheet reference comprehensive pressure characterization value P(1,i) to obtain the first change ΔP(u,i)=P(u,i)-P(1,i); The difference between the second comprehensive pressure characterization value P(d,i) and the lower thin sheet reference comprehensive pressure characterization value P(3,i) is used to obtain the second change ΔP(d,i)=P(d,i)-P(3,i); S43. Define the pressure deviation value of the i-th anti-eccentricity mechanism as e. i e i =ΔP(u,i)-ΔP(d,i); If e i If the value is greater than 0, it is determined that the workbench at the i-th anti-eccentricity mechanism has an upward tilting trend. If e i If the value is 0, then the workbench at the i-th anti-eccentricity mechanism is determined to have a downward trend; S5. Calculate the oil pressure adjustment amount: For the two radially opposite anti-eccentric load mechanisms A and B, perform coordinated control of the oil pressure of A and B: Let e ​​= (e A -e B When |e|≦ε, no oil pressure regulation is performed; when |e|>ε, the oil pressure adjustment amount of mechanisms A and B is calculated. ; When e > ε, mechanism A tilts upwards and mechanism B tilts downwards. Therefore, ΔP(A,up) and ΔP(B,down) are calculated according to the principle of equal thrust distribution: ; ; When e < -ε, mechanism A sinks and mechanism B rises. Therefore, ΔP(A,down) and ΔP(B,up) are calculated according to the principle of equal thrust distribution: ; ; in, ε is a preset threshold; e A This indicates the pressure deviation value of the anti-eccentric loading mechanism A; e B This indicates the pressure deviation value of the anti-eccentric loading mechanism B; ΔP(A,up) represents the oil pressure adjustment amount of the oil circuit on the anti-eccentric load mechanism A; ΔP(A,down) represents the oil pressure adjustment amount of the lower oil circuit of the anti-eccentric load mechanism A; ΔP(B,down) represents the oil pressure adjustment amount of the lower oil circuit of the anti-eccentric load mechanism B; ΔP(B,up) represents the oil pressure adjustment amount of the oil circuit on the anti-eccentric load mechanism B; F need The total corrective force required to eliminate the current off-center loading tendency of the worktable; η Aup This represents the transmission coefficient of the upper oil circuit of the anti-eccentric loading mechanism A; η Adown This represents the transmission coefficient of the lower oil circuit of the anti-eccentric loading mechanism A; η Bdown This represents the transmission coefficient of the lower oil circuit of the anti-eccentric loading mechanism B; η Bup This represents the transmission coefficient of the upper oil circuit of the anti-eccentric loading mechanism B; K f K represents the force-deviation conversion factor. f Used to convert pressure deviation e into the required total corrective force F need It can be determined through mechanical analysis or experimental calibration; the unit is N / MPa. S6. Hydraulic pressure linkage compensation: If e>ε, anti-eccentric load mechanism A is judged to have an upward trend, and mechanism B is judged to have a downward trend. Then, the oil pressure of the upper oil circuit (7) controlling anti-eccentric load mechanism A increases by ΔP(A,up), and the oil supply pressure of the lower oil circuit (8) controlling mechanism B increases by ΔP(B,down), that is: P A上 =P0+ΔP(A,up); and P B下 =P0+ΔP(B,down); and P A下 =P B上 =P0; If e < -ε, anti-eccentricity mechanism A is determined to have a downward tendency, and mechanism B is determined to have an upward tendency. Then, the oil pressure of the lower oil circuit (8) controlling anti-eccentricity mechanism A increases by ΔP(A,down), and the oil supply pressure of the upper oil circuit (7) controlling mechanism B increases by ΔP(B,up), that is: P A下 =P0+ΔP(A,down); and P B上 =P0+ΔP(B,up); and P A上 =P B下 =P0; Where P A上 To prevent the oil supply pressure of the upper oil circuit (7) of the off-center loading mechanism A; P A下 To prevent the oil supply pressure of the lower oil circuit (8) of the off-center loading mechanism A; P B上 To prevent the oil supply pressure of the upper oil circuit (7) of the off-center loading mechanism B; P B下 To prevent the oil supply pressure of the lower oil circuit (8) of the off-center loading mechanism B; Repeat steps S3-S6 until the processing is complete; When the worktable needs to rotate, the upper oil circuit (7) and lower oil circuit (8) of all anti-eccentric load mechanisms are depressurized to prevent the upper elastic plate (3) and lower elastic plate (4) from deforming and to maintain a preset rotation gap with the worktable.

2. The method for preventing off-center load detection and control according to claim 1, characterized in that: After step S4 and before step S5, the system further includes verifying the off-center load trend determination result, including the following steps: Off-center load trend verification of opposing mechanisms: cross-verification is performed based on the off-center load trend determination results of two radially opposite anti-off-center load mechanisms A and B. If the off-center load mechanisms A and B have opposite trends, the trend verification is passed; if the off-center load mechanisms A and B have the same trend, the system issues an "abnormal trend" alarm signal, and the system controls the pressure of all oil circuits of all anti-off-center load mechanisms to P0.

3. The method for preventing off-center load detection and control according to claim 2, characterized in that: After the off-center loading trend verification of the opposing mechanism is completed, the amplitude and verification are also performed: Let S=e A +e B e A and e B This represents the pressure deviation at points A and B, two radially opposite anti-eccentricity loading mechanisms; if |S| If δ is true, the amplitude and verification pass; if |S|≧δ, the system issues a "sensor consistency abnormality" alarm signal; the system controls the pressure of all oil circuits of all anti-eccentric load mechanisms to P0; where δ is a preset threshold.

4. The method for preventing off-center load detection and control according to claim 3, characterized in that: After the amplitude and verification are completed, circumferential continuity verification is also performed: for three adjacent anti-eccentric load mechanisms: if the trends of the two side mechanisms are the same and the trend of the middle mechanism is opposite to that of the two side mechanisms, the system issues an "abnormal trend oscillation" alarm signal, and the system controls the pressure of all oil circuits of all anti-eccentric load mechanisms to P0.

5. The method for preventing off-center load detection and control according to claim 1, characterized in that: The preset algorithm in step S1 is either an arithmetic mean or a weighted average.

6. The method for preventing off-center load detection and control according to claim 1, characterized in that, After performing step S6, step S7, feedback correction, is performed: real-time acquisition of the comprehensive deviation signal e after the oil pressure adjustment amount following step S5. new =(e A’ -e B’ ) / 2; when |e new When |≦λ, no oil pressure regulation is performed; when |e new When |>λ, a closed-loop control model is adopted, allowing e to... new Approaching 0, calculate the common hydraulic pressure correction ΔP for anti-eccentric loading mechanisms A and B. 修 ; When e>λ, anti-eccentricity mechanism A is determined to have an upward tendency, and mechanism B is determined to have a downward tendency. Then, the oil pressure in the upper oil circuit (7) of anti-eccentricity mechanism A and the lower oil circuit (8) of mechanism B both increase by ΔP. 修 That is, P A上修 =P A上 +|ΔP 修 |;P B下修 =P B下 +|ΔP 修 |; When e -λ, if anti-eccentric load mechanism A is determined to have a downward tendency and mechanism B is determined to have an upward tendency, then the oil pressure of the lower oil circuit (8) of anti-eccentric load mechanism A and the upper oil circuit (7) of mechanism B will both increase by ΔP. 修 That is, P A下修 =P A下 +|ΔP 修 |;P B上修 =P B上 +|ΔP 修 |; λ is a preset threshold; e A’ The pressure deviation value of the anti-eccentric load mechanism A after the hydraulic linkage compensation in step S6; e B’ The pressure deviation value of the anti-eccentric load mechanism B after the hydraulic linkage compensation in step S6; P A上修 The upper oil circuit pressure of the anti-eccentric load mechanism A after feedback correction in step S7; P A下修 The lower oil circuit pressure of the anti-eccentric load mechanism A after feedback correction in step S7; P B上修 The upper oil circuit pressure of the anti-eccentric load mechanism B after feedback correction in step S7; P B下修 The lower oil circuit pressure of the anti-eccentric load mechanism B after feedback correction in step S7; P A上 The oil supply pressure of the upper oil circuit (7) of the anti-eccentric load mechanism A after the oil pressure linkage compensation in step S6; P A下 The oil supply pressure of the lower oil circuit (7) of the anti-eccentric load mechanism A after the oil pressure linkage compensation in step S6; P B上 The oil supply pressure of the upper oil circuit (7) of the anti-eccentric load mechanism B after the oil pressure linkage compensation in step S6; P B下 The oil supply pressure of the lower oil circuit (7) of the anti-eccentric load mechanism B after the oil pressure linkage compensation in step S6; Repeat steps S3-S7 until the processing is complete.

7. A CNC machine tool rotary table anti-eccentricity mechanism applicable to the anti-eccentricity detection and control method according to any one of claims 1-6, characterized in that: The system includes a base, one side of which has a U-shaped groove; an upper elastic plate (3) is installed on the upper side wall of the groove; a lower elastic plate (4) is installed on the lower side wall of the groove; an upper oil passage (7) and a lower oil passage (8) are provided on the base; a plurality of upper receiving cavities (5) are provided on the upper side of the groove, and the plurality of upper receiving cavities (5) are interconnected through upper oil passages (10); one end of the upper oil passage (7) extends into one of the upper receiving cavities (5); the groove... The lower side is provided with several lower receiving cavities (6), which are interconnected by a lower oil passage (11). One end of the lower oil passage (8) extends into one of the lower receiving cavities (6). Several upper thin-film pressure sensors (12) are installed between the upper elastic sheet (3) and the base. Several lower thin-film pressure sensors (13) are installed between the lower elastic sheet (4) and the base. Both the upper oil passage (7) and the lower oil passage (8) are connected to the oil supply system.

8. The anti-eccentric loading mechanism for the rotary table of a CNC machine tool according to claim 7, characterized in that, The base includes an upper seat (2) and a lower seat (1). The upper oil passage (7) is opened in the upper seat (2), and the lower oil passage (8) is opened in the lower seat (1). The upper seat (2) and the lower seat (1) are connected by several screws. The upper seat (2) and the lower seat (1) are assembled to form the "U"-shaped groove.

9. The anti-eccentricity mechanism for the rotary table of a CNC machine tool according to claim 8, characterized in that: A pad (9) is also installed between the upper seat (2) and the lower seat (1).

10. The anti-eccentric loading mechanism for the rotary table of a CNC machine tool according to claim 7, characterized in that: The upper receiving cavity (5) and the lower receiving cavity (6) are respectively a number of countersunk holes or grooves arranged at intervals along the length of the groove.

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