Novel parameter interpolation method and system for numerical control system and numerical control machine tool

Abstract

The present application belongs to the field of numerical control data processing technology in mechanical manufacturing engineering, and discloses a novel parameter interpolation method, system and numerical control machining tool for numerical control system. The method comprises the following steps: feed rate scheduling, interpolation parameter precision scheduling; subdividing the interpolation period periodically sent by the computer numerical control system (CNC) into interpolation parameter precision; performing FDI parameter interpolation of three axes of the tool axis based on the subdivided interpolation parameter precision; performing FDI parameter interpolation of five axes in combination with the chord height error constraint model of the tool axis, obtaining the interpolation trajectory of the tool axis, and visually showing it. Compared with the SIP method, the FSI method proposed by the present application significantly improves the cutting quality of S-shaped parts. The FDI proposed can be used to obtain high-precision interpolation parameters in theory, has high real-time performance, and the FSI proposed is more conducive to improving the cutting quality of five-axis machining.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of numerical control data processing in mechanical manufacturing engineering, and discloses a novel parameter interpolation method, system and numerical control machining machine tool for a numerical control system. BACKGROUND

[0002] In the field of free-form surface machining, parameter interpolation has significant advantages in reducing approximation error and improving feed stability compared with traditional linear and circular interpolation, and has been a research topic for many scholars. In traditional parameter interpolation methods, the STE interpolator is often used by scholars due to its high precision and high stability. However, Taylor interpolation algorithm inevitably introduces truncation error by removing high-order infinitesimal. The method for improving interpolation parameter precision is mainly divided into two categories: direct interpolation method and iterative method. In the direct interpolation method, the most widely used is Taylor expansion method, which writes the interpolation parameter u as a function of time t, and uses Taylor series expansion at the next parameter position, which requires first-order and second-order derivatives, or an additional third-order derivative term. Although the interpolation parameter can be directly obtained by Taylor method, truncation error is inevitable. When the number of retained terms increases, the truncation error can be reduced, but the amount of calculation also increases. The calculation of high-order derivatives in Taylor expansion greatly reduces the real-time performance of NURBS interpolator. The iterative method for calculating interpolation parameters mainly refers to the "predict-correct" interpolation algorithm. Ye et al. also studied the iterative compensation method of Taylor expansion interpolation. The interpolation parameter is estimated by Taylor method or velocity polynomial method, and the deviation between the target velocity and the actual velocity obtained by the estimation method is calculated. In order to reduce the velocity deviation, the actual velocity and the target velocity are used to iteratively feedback and correct the interpolation parameter. The condition for stopping the iterative compensation is to reach the set interpolation accuracy.

[0003] However, in order to realize feedback correction, the "predict-correct" interpolation method needs to perform iterative calculation with indefinite time in each interpolation period, which affects the real-time performance of the algorithm. Once the iterative calculation is not completed within the interpolation period, it will cause emergency stop or numerical control system crash and other consequences. The calculation of high-order derivatives and the compensation of truncation error have become the bottleneck of improving the NURBS interpolation accuracy. In five-axis machining, the interpolation parameters of tool tip and tool axis vector are obtained by the same parameters in traditional method. It cannot reflect the curvature change of the surface, and it is obviously unreasonable to fully exert the advantages of five-axis.

[0004] Second Taylor Expension (STE) interpolator is usually used by scholars due to its high precision and G3 continuity or higher, so high-precision machining is limited by truncation error and second derivative calculation burden. In the conventional method, the increase of the interpolation parameter precision in the Taylor expansion interpolator will greatly increase the calculation burden of high-order derivatives or compensation methods, resulting in a decrease in real-time performance.

[0005] Through the above analysis, the problems and defects of the prior art are:

[0006] (1) In the cutting of five-axis machining, the prior art has a high CPU overhead and reduces the interpolation real-time performance due to the high calculation burden of the interpolation parameter based on the Taylor expansion, which cannot effectively improve the machining precision and efficiency.

[0007] (2) In the five-axis machining of the prior art, the interpolation parameters of the tool tip cannot be calculated only by FDI, and the interpolation parameters of the tool axis vector cannot be directly obtained by FSI, which cannot significantly improve the cutting quality of S-shaped parts, resulting in low machining real-time performance and more accurate control of the tool tip error and actual cutting.

[0008] (3) In the prior art, the parameter interpolation method based on the first-order and second-order Taylor expansion has truncation error. If the truncation error is compensated, the interpolation real-time performance will be reduced. SUMMARY

[0009] To overcome the problems in the related art, the present application discloses a new parameter interpolation method for a numerical control system, a system and a numerical control machining tool. The technical solution is as follows:

[0010] The new parameter interpolation method for a numerical control system is applied to PC and ARM systems, and the method comprises the following steps:

[0011] S1, feed rate scheduling: scheduling the feed rate of the tool tip interpolation speed and the tool axis interpolation speed, converting the chord error constraint δ0 of the tool axis trajectory of the STM into the chord error constraint δ of the tool tip trajectory of the MTM t , obtaining the tool axis feed rate;

[0012] S2, interpolation parameter precision scheduling: based on the obtained tool axis feed rate, the interpolation period T s of the computer numerical control system is subdivided into interpolation parameter precision t i,k ;

[0013] S3, based on the tool tip feed rate obtained in step S1 and the interpolation parameter precision t i,k subdivided in step S2, three-axis tool tip FDI parameter interpolation is performed;

[0014] S4, the tool tip point error constraint is combined with the tool axis chord height error constraint model to generate a five-axis chord height error constraint model, and the three-axis tool tip FDI parameter interpolation in step S3 is combined to obtain a five-axis tool axis interpolation trajectory.

[0015] In step S1, the feed rate of the tool tip interpolation speed and the tool axis interpolation speed is γ, and γ>1;

[0016]

[0017] In the formula, ||C t (u)||,||C o (u)|| is the total length of the tool tip point curve and the tool axis curve, respectively, ||ΔC t (u)||,||ΔC o (u)|| is the length of the tool tip point curve and the tool axis curve in the interpolation period, respectively, C t (u),V t (u) is the tool tip point curve and the tool tip feed rate, respectively, C o (u),V o (u) is the tool axis curve and the tool axis feed rate, respectively.

[0018] In one embodiment, in the scheduling of the feed rate of the tool tip interpolation speed and the tool axis interpolation speed, the relationship between the curvature and the radius is obtained; the curvature k is defined as:

[0019]

[0020] In the formula, k is the curvature, Δs is the circular arc, and Δa is the central angle.

[0021] In step S1, in the process of obtaining the tool axis feed rate, the chord height error of the tool axis vector mapped into the tool tip interpolation trajectory is:

[0022]

[0023] In the formula, δ t is the chord error constraint of the tool tip trajectory, u i is the i-th interpolation parameter, ρ t is the curvature radius of the tool tip trajectory, is the square of the tool tip curvature radius, V t is the tool tip feed rate, T s is the interpolation period, γ is the feed rate of the tool tip interpolation speed and the tool axis interpolation speed, ρ o is the curvature radius of the tool axis trajectory, is the square of the tool axis vector curve curvature radius, V o is the tool axis vector feed rate, δ o is the chord error constraint of the tool axis trajectory.

[0024] In one embodiment, the tip-chord error constraint of the tool tip and tool axis vector is the chord error constraint δ o of the tool axis trajectory and the chord error constraint δ t of the tool tip trajectory, expressed as:

[0025] δ t,o = min(γδ o , δ t )

[0026] where δ t,o is the common chordal error of the tool tip point and tool axis.

[0027] In step S2, the IPA calculation formula is:

[0028]

[0029] where t i,k is the interpolation parameter precision, k and strlen(strstr(t i , ".") - 1) are the number of decimal points, str(len - 1) is the last digit of the decimal point, and len is the length of t i ; if the last digit of the decimal point is an integer multiple of 10, i.e., 2 or 5, then t i,k is 2 x 10 -k or 5 x 10 -k ; if not, then t i,k is 10 -k .

[0030] In step S3, the three-axis tool tip FDI parameter interpolation formula is:

[0031]

[0032] where u i+1 is the i+1th interpolation parameter, u i is the ith interpolation parameter, T s is the interpolation period, is the feed rate corresponding to the ith interpolation parameter of the tool tip point, t i,k is the interpolation parameter precision, and ||C'(u i )|| is the modulus of the first derivative of the curve.

[0033] In step S4, the tool axis chordal error constraint model is:

[0034]

[0035] where δ(u i ) is the chordal error, and p(u i ) is the curvature, p 2(u i ) is the square of the curvature, V(u i ) is the feed rate;

[0036] The five-axis chord error constraint model is:

[0037]

[0038] δ t,o = min(γδ o ,δ t )

[0039] In the formula: δ o→t (u i ) is the chord error of the tool axis mapping to the tool tip point surface, ρ t (u i ) is the tool tip point curve curvature, is the square of the tool tip point curvature radius, V t (u i ) is the tool tip point feed rate, T s is the interpolation period, γ is the feed rate of the tool tip interpolation speed and the tool axis interpolation speed, ρ o (u i ) is the tool axis curve curvature, V o (u i ) is the tool axis feed rate, δ o (u i ) is the tool axis chord error, δ t,o is the common chord error of the tool tip point and the tool axis, δ o is the chord error constraint of the tool axis trajectory, δ t is the chord error constraint of the tool tip trajectory;

[0040] The five-axis tool tip FDI parameter interpolation formula is:

[0041]

[0042] In the formula, u i+1,1 is the i+1th interpolation parameter when the last digit of the decimal part is 1, u i+1,2 is the i+1th interpolation parameter when the last digit of the decimal part is 2, u i+1,5 is the i+1th interpolation parameter when the last digit of the decimal part is 5, u i,1 is the i interpolation parameter when the last digit of the decimal part is 1, u i,2 is the i interpolation parameter when the last digit of the decimal part is 2, u i,5 is the i interpolation parameter when the last digit of the decimal part is 5;

[0043] is the feed rate when the first IPA is 1 at the end of the decimal, is the feed rate at the first IPA when the last digit of the decimal is 1, is the feed rate at the kth IPA when the last digit of the decimal is 1, is the feed rate at the last IPA when the last digit of the decimal is 1; is the last digit of the decimal of the IPA precision is the same as the decimal part of the feed rate, and the last digit is 1;||C'(u i,1 is the modulus of the first derivative of the curve when the last digit of the IPA precision is 1;

[0044] is the feed rate at the first IPA when the last digit of the decimal is 2, is the feed rate at the second IPA when the last digit of the decimal is 2, is the feed rate at the mth IPA when the last digit of the decimal is 2, is the feed rate at the last IPA when the last digit of the decimal is 2; is the last digit of the decimal of the IPA precision is the same as the decimal part of the feed rate, and the last digit is 2;||C'(u i,2 is the modulus of the first derivative of the curve when the last digit of the IPA precision is 2;

[0045] is the feed rate at the first IPA when the last digit of the decimal is 5, is the feed rate at the second IPA when the last digit of the decimal is 5, is the feed rate at the nth IPA when the last digit of the decimal is 5, is the feed rate at the last IPA when the last digit of the decimal is 5; is the last digit of the decimal of the IPA precision is the same as the decimal part of the feed rate, and the last digit is 5;||C'(u i,5 is the modulus of the first derivative of the curve when the last digit of the IPA precision is 5;

[0046] In five-axis FDI parameter interpolation, the interpolation parameter formula of the five-axis CNC machining tool is:

[0047]

[0048] wherein, u i+1,t is the i+1th interpolation parameter of the tool tip point, u i,t is the ith interpolation parameter of the tool tip point, T s is the interpolation period, N' i,p (u) is the base function, p i,wx , p i,wy , p i,wz are all tool tip control points, o i,wx , o i,wyo i,wz are tool axis control points, (x, y, z) is control point coordinates, t i,k is interpolation parameter precision, n is control point number, w is workpiece coordinate system, u i+1,o is the i+1th interpolation parameter of the tool axis, u i,o is the i-th interpolation parameter of the tool axis.

[0049] Another object of the present application is to provide a new parameter interpolation system for implementing the new parameter interpolation method for the numerical control system, applied to PC and ARM systems, which comprises:

[0050] A tool tip trajectory acceleration and deceleration control module is used for S-shaped flexible acceleration and deceleration of the tool tip trajectory in cutting.

[0051] A feed rate scheduling module is used for scheduling the feed rate of the tool tip interpolation speed and the tool axis interpolation speed, and converting the chord error constraint δ0 of the tool axis trajectory of the STM into the chord error constraint δ t of the tool tip trajectory of the MTM; The tool axis feed rate is obtained.

[0052] An interpolation parameter precision scheduling module is used for scheduling the interpolation period T s subdivided into interpolation parameter precision t i,k .

[0053] A three-axis FDI parameter interpolation module is used for three-axis tool tip FDI parameter interpolation based on the subdivided interpolation parameter precision t i,k .

[0054] A tool axis interpolation trajectory acquisition module is used for five-axis FDI parameter interpolation combined with the tool axis chord height error constraint model to obtain the tool axis interpolation trajectory.

[0055] Another object of the present application is to provide a numerical control machine tool for implementing the new parameter interpolation method for the numerical control system.

[0056] In combination with all the above technical solutions, the present application has the following advantages and positive effects:

[0057] First, in view of the technical problems existing in the prior art and the difficulty in solving the problems, the present application closely combines the technical solutions to be protected and the results and data in the research and development process, and analyzes in detail and depth how the technical solutions solve the technical problems and bring some creative technical effects after solving the problems, which are described as follows: in view of the technical bottleneck existing in the prior art, the present application proposes a non-uniform rational B-spline (NURBS) feed rate directly interpolation (FDI). Since the interpolation period Ts Unlike the traditional method based on S-shaped acceleration and deceleration, the duration is not an integer multiple, so the rounding method of the feed duration must be used, while the proposed FDI completely follows the original feed rate schedule generated by the feed rate. FDI is an equation, not an inequality like STE, which can theoretically guarantee the accuracy of the interpolation parameters. In addition, computer numerical control (CNC) systems are essentially discrete-time systems, not continuous-time systems. Based on the discrete characteristics, the FDI equation is discretized to follow the accuracy of the original feed duration, i.e., the exact mapping of the NURBS curve. The consistent accuracy theoretically greatly guarantees the accuracy of the interpolation parameters. Only in the case of the original feed rate, FDI can directly obtain theoretically accurate interpolation parameters without any rounding and compensation methods.

[0058] In the NURBS interpolator, the improvement of the interpolation parameter accuracy in the prior art Taylor expansion interpolator will lead to a great increase in the calculation burden of high-order derivatives or compensation methods. FDI directly breaks this. Using the method proposed in the present application, the interpolation parameters can be directly obtained using only the duration of the feed rate schedule and the first derivative. The FDI equation is consistent with the original feed schedule time τ1-τ7, and the IPA accuracy greatly guarantees the accuracy of the interpolation parameters in theory. Without increasing the calculation burden, the proposed FDI can effectively improve the machining accuracy. It has good real-time performance and does not need to compensate for STE, periodic rounding, and second-order derivatives. Compared with the other two algorithms, the proposed FDI method can significantly improve the machining accuracy while having lower CPU overhead. In the experiment, the chord error of FDI is smaller than that of STE-IC and STE-FR, and the time consumption of FDI is also the smallest among STE-IC and STE-FR. The proposed FDI is conducive to realizing high-precision and high-efficiency machining in the field of CNC machining. In addition, the FSI method is proposed for double NURBS in five-axis machining. Only by calculating the tool tip interpolation parameters through FDI, the interpolation parameters of the tool axis vector are directly obtained through FSI, and the real-time performance is high. In the experiment, the tool posture of FSI is almost parallel to the ideal posture, while the tool posture of SIP is crossed with the ideal posture. Compared with the SIP method, the proposed FSI method significantly improves the cutting quality of S-shaped parts. The proposed FDI can be used to theoretically obtain high-precision interpolation parameters, and the proposed FSI is more conducive to improving the cutting quality of five-axis machining. Further work can emphasize more accurate control of the tool tip error and actual cutting.

[0059] Second, the technical solution is regarded as a whole or from the product point of view, the technical effect and advantages of the technical solution to be protected by the application are described as follows: the FDI is used, and a double NURBS feed rate synchronization interpolation (FSI) method for five-axis machining is provided. The FDI only needs to calculate the tool tip interpolation parameter, the FSI can directly obtain the tool tip interpolation parameter, the tool shaft posture is optimal, and real-time performance is high. The FSI can make the tool shaft orientation vector closer to the surface normal direction, and is more conducive to improving the cutting quality. Experiments are carried out on a machine tool, and it is proved that the method has advantages in improving machining efficiency and interpolation parameter accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0060] The drawings incorporated into the specification and constituting a part of the specification show embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure;

[0061] Figure 1 It is a new parameter interpolation method flow chart for a numerical control system provided by the embodiment of the application;

[0062] Figure 2 It is a new parameter interpolation method principle diagram for a numerical control system provided by the embodiment of the application;

[0063] Figure 3 It is a kinematics transmission matrix principle diagram of a tilt table type five-axis machine tool and a worktable provided by the embodiment of the application;

[0064] Figure 4 It is a tool shaft chord height error constraint principle diagram in five-axis machining provided by the embodiment of the application;

[0065] Figure 5 It is an experimental platform schematic diagram provided by the embodiment of the application;

[0066] Fig. 6(a) is a butterfly angle schematic diagram in 6 corners marked as 1-6 for performing experiments to verify the embodiment provided by the application;

[0067] Fig. 6(b) is a first butterfly angle test piece improvement effect diagram provided by the embodiment of the application;

[0068] Fig. 6(c) is a second butterfly angle test piece improvement effect diagram provided by the embodiment of the application;

[0069] Fig. 6(d) is a third butterfly angle test piece improvement effect diagram provided by the embodiment of the application;

[0070] Fig. 6(e) is a fourth butterfly angle test piece improvement effect diagram provided by the embodiment of the application;

[0071] Fig. 6(f) is a modified effect diagram of the 5th butterfly angle test piece according to an embodiment of the present application;

[0072] Fig. 6(g) is a modified effect diagram of the 6th butterfly angle test piece according to an embodiment of the present application;

[0073] Figure 7 is a schematic diagram for comparing FSI and SIP according to an embodiment of the present application. DETAILED DESCRIPTION

[0074] In order to make the above objectives, characteristics and advantages of the present application more apparent, specific embodiments of the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of ways other than those described herein without departing from the spirit of the present application. It is to be understood that similar improvements can be made by those skilled in the art in other ways, and therefore the present application is not limited to the specific embodiments disclosed below.

[0075] I. Explanation of Embodiments

[0076] Embodiment 1, as shown in the drawings, the new parameter interpolation method for a numerical control system according to an embodiment of the present application includes the following steps: Figure 1 S1, feed rate scheduling: scheduling the feed rate of the tool tip interpolation speed and the tool axis interpolation speed, converting the chord error constraint δ0 of the tool axis trajectory of the STM into the chord error constraint δ t of the tool tip trajectory of the MTM;

[0077] S2, interpolation parameter accuracy scheduling: based on the obtained tool axis feed rate, subdividing the interpolation period T s of the computer numerical control system into interpolation parameter accuracy t i,k ;

[0078] S3, three-axis tool tip FDI parameter interpolation based on the subdivided interpolation parameter accuracy t i,k ;

[0079] S4, combining the tool tip point error constraint with the tool axis chord height error constraint model to generate a five-axis chord height error constraint model, and combining the five-axis tool tip FDI parameter interpolation to obtain the tool axis interpolation trajectory under five-axis.

[0080] In the embodiments of the present application, as shown in the drawings, the principle of the new parameter interpolation method for a numerical control system according to an embodiment of the present application.

[0081] Figure 2

[0082] ​​The interpolation in the numerical control system is usually based on Taylor expansion, which has a truncation error and reduces the machining precision. However, the numerical control system of Tian Da Precision Co., Ltd. adopts a novel interpolation method of FDI, which effectively provides the machining precision.

[0083] In step S1, the feed rate of the tool tip interpolation speed and the tool axis interpolation speed is γ, and γ>1;

[0084]

[0085] The tool tip point trajectory and the tool axis trajectory are two trajectories of the same tool handle, so the two trajectories are synchronized in each interpolation period, and the whole trajectory is also synchronized. t (u),||ΔC o (u) are the total lengths of the tool tip point curve and the tool axis curve, respectively. t (u),||ΔC o (u) are the lengths of the tool tip point curve and the tool axis curve in the interpolation period, respectively. t (u),V t (u) are the tool tip point curve and the tool tip feed rate, respectively. o (u),V o (u) are the tool axis curve and the tool axis feed rate, respectively.

[0086] In the scheduling of the feed rate of the tool tip interpolation speed and the tool axis interpolation speed, the relationship between the curvature and the radius is obtained; the curvature k is defined as:

[0087]

[0088] In the formula, k is the curvature, Δs is the circular arc, and Δa is the central angle.

[0089] In step S1, in the process of obtaining the tool axis feed rate, the chord height error of the tool axis vector mapped into the tool tip interpolation trajectory is:

[0090]

[0091] In the formula, δ t is the chord error constraint of the tool tip trajectory, u i is the i-th interpolation parameter, ρ t is the curvature radius of the tool tip trajectory, is the square of the tool tip curvature radius, V t is the tool tip feed rate, T s is the interpolation period, γ is the feed rate of the tool tip interpolation speed and the tool axis interpolation speed, ρ o is the curvature radius of the tool axis trajectory, is the square of the tool axis vector curve curvature radius, V ois the tool axis vector feed rate, δ o is the chord error constraint of the tool axis trajectory.

[0092] the tool tip and tool axis vector tool tip chord error constraint δ t,o is the chord error constraint of the tool axis trajectory. o and the tool tip trajectory chord error constraint δ t is the minimum value in the expression:

[0093] δ t,o = min(γδ o ,δ t )

[0094] wherein δ t,o is the common chord height error of the tool tip point and tool axis.

[0095] In step S2, the IPA calculation formula is:

[0096]

[0097] wherein k and strlen(strstr(τ i ,".")-1) are the number of decimal points, str(len-1) is the last digit of the decimal point, and len is the length of τ i ; if the last digit of the decimal point is an integer multiple of 10, i.e. 2 or 5, then t i,k is 2x10 -k or 5x10 -k ; if not, then t i,k is 10 -k .

[0098] In step S3, the three-axis tool tip FDI parameter interpolation formula is:

[0099]

[0100] wherein u i+1 is the i+1th interpolation parameter, u i is the ith interpolation parameter, T s is the interpolation period, is the feed rate corresponding to the ith interpolation parameter of the tool tip point, t i,k is the interpolation parameter precision, and ||C'(u i )|| is the modulus of the first derivative of the curve.

[0101] In step S4, the tool axis chord height error constraint model is:

[0102]

[0103] wherein δ(u i) is the chord height error, ρ(u) i ) is curvature, ρ 2 (u i V(u) is the square of the curvature. i ) is the feed rate;

[0104] The five-axis chord height error constraint model is as follows:

[0105]

[0106] δ t,o =min(γδ) o ,δ t )

[0107] Where: δ o→t (u i ) is the chord height error mapped from the tool axis to the tool tip surface, ρ t (u i ) is the curvature of the curve at the tip of the knife. It is the square of the radius of curvature at the blade tip, V t (u i T is the tool tip feed rate. s ρ is the interpolation cycle, γ is the feed rate between the tool tip interpolation speed and the tool axis interpolation speed, and ρ is the interpolation period. o (u i ) is the curvature of the tool axis curve, V o (u i ) is the tool axis feed rate, δ o (u i ) represents the chord height error of the cutter shaft, δ t,o It is the common chord height error of the tool tip and the tool axis, δ o It is the chordal error constraint of the tool axis trajectory, δ t It is the chordal error constraint of the tool tip trajectory;

[0108] The interpolation formula using the FDI parameter of the tool tip in a five-axis tool path is as follows:

[0109]

[0110] In the formula, u i+1,1 It is the (i+1)th interpolation parameter when the last digit of the decimal part is 1, u i+1,2 It is the (i+1)th interpolation parameter when the last digit of the decimal part is 2, u i+1,5 It is the (i+1)th interpolation parameter when the last digit of the decimal part is 5, u i,1 It is the i-th interpolation parameter when the last digit of the decimal part is 1, u i,2 It is the i-th interpolation parameter when the last digit of the decimal part is 2, u i,5 It is the i-th interpolation parameter when the last digit of the decimal part is 5;

[0111] is the feed rate at the first IPA when the last digit of the decimal is 1, is the feed rate at the second IPA when the last digit of the decimal is 1, is the feed rate at the kth IPA when the last digit of the decimal is 1, is the feed rate at the last IPA when the last digit of the decimal is 1; is the IPA precision with the same number of decimal digits as the number of decimal digits of the feed rate, and the last digit is 1;||C'(u i,1 is the modulus of the first derivative of the curve when the last digit of the IPA precision is 1;

[0112] is the feed rate at the first IPA when the last digit of the decimal is 2, is the feed rate at the second IPA when the last digit of the decimal is 2, is the feed rate at the mth IPA when the last digit of the decimal is 2, is the feed rate at the last IPA when the last digit of the decimal is 2; is the IPA precision with the same number of decimal digits as the number of decimal digits of the feed rate, and the last digit is 2;||C'(u i,2 is the modulus of the first derivative of the curve when the last digit of the IPA precision is 2;

[0113] is the feed rate at the first IPA when the last digit of the decimal is 5, is the feed rate at the second IPA when the last digit of the decimal is 5, is the feed rate at the nth IPA when the last digit of the decimal is 5, is the feed rate at the last IPA when the last digit of the decimal is 5; is the IPA precision with the same number of decimal digits as the number of decimal digits of the feed rate, and the last digit is 5;||C'(u i,5 is the modulus of the first derivative of the curve when the last digit of the IPA precision is 5;

[0114] In five-axis FDI parameter interpolation, the interpolation parameter formula of the five-axis CNC machining tool is:

[0115]

[0116] wherein, u i+1,t is the (i+1)th interpolation parameter of the tool tip point, u i,t is the ith interpolation parameter of the tool tip point, T s is the interpolation period, N' i,p (u) is the base function, p i,wx , p i,wy , pi,wz All are tool tip control points, o i,wx , i,wy , i,wz All are tool axis control points, (x, y, z) is control point coordinates, t i,k is interpolation parameter precision, n is the number of control points, w is the workpiece coordinate system, u i+1,o is the i+1th interpolation parameter of the tool axis, u i,o is the i-th interpolation parameter of the tool axis. The double spline is two spline curves, the tool tip is one of them, and the tool axis is the other; the tool tip control point and the tool axis control point are the basis of the spline curve, and the coordinate point is the known data.

[0117] Embodiment 2, the embodiment of the application also provides a novel parameter interpolation system in five-axis machining, comprising:

[0118] A tool tip trajectory acceleration and deceleration control module is configured to perform S-shaped flexible acceleration and deceleration on the tool tip trajectory in cutting;

[0119] A feed rate scheduling module is configured to schedule the feed rates of the tool tip interpolation speed and the tool axis interpolation speed, and convert the chord error constraint δ0 of the tool axis trajectory of the STM into the chord error constraint δ t of the tool tip trajectory of the MTM;

[0120] An interpolation parameter precision scheduling module is configured to subdivide the interpolation period T s periodically sent by a computer numerical control system (CNC) into interpolation parameter precisions t i,k ;

[0121] A three-axis FDI parameter interpolation module is configured to perform tool tip FDI parameter interpolation under three-axis based on the subdivided interpolation parameter precisions t i,k ;

[0122] A tool axis interpolation trajectory acquisition module is configured to acquire the tool axis interpolation trajectory by combining the tool axis chord height error constraint model and performing FDI parameter interpolation under five-axis.

[0123] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in a certain embodiment can be referred to the related description of other embodiments.

[0124] The information interaction, execution process and other contents between the above devices / units, since based on the same concept as the method embodiments of the application, the specific functions and the technical effects brought by them can be referred to the method embodiment part, and will not be repeated here.

[0125] Those skilled in the art will understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the functions described above can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this invention. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments.

[0126] Example 3: In this embodiment of the invention, taking a five-axis CNC machine tool as an example, the novel parameter interpolation method for CNC systems provided by this embodiment of the invention is as follows:

[0127] In this embodiment of the invention, the next interpolation parameter u can be directly obtained through the Feed Rate Direct Interpolator (FDI) method. i+1 In FDI, the formula for incremental triaxial interpolation of the interpolation parameter u relative to time t is:

[0128]

[0129] Compared to STE, real-time performance is improved, and no second derivative is required. Furthermore, the above equation is a full equation rather than an approximation, theoretically guaranteeing the interpolation parameter u. i+1 The accuracy is not guaranteed. However, STE is an approximation. STE is a continuous time-domain analysis, and a CNC system cannot continuously send position commands. A CNC has many tasks to perform, and sending position commands is only one of them. Therefore, the CNC will adjust the position in the interpolation period T. s The position is sent periodically. Therefore, CNC is not inherently a continuous-time system, but a discrete-time system. s The smaller the value, the higher the accuracy. Although T... s Even at smaller values, the command position sequence remains discrete. FDI fully utilizes this discrete characteristic to improve the accuracy of the interpolation parameters. To maximize the interpolation parameter u... i+1 The accuracy will be determined by the interpolation period T. s Subdivided into t i,k And named Interpolation Parameter Precision (IPA). All t i,k The sum is an interpolation period T s .

[0130] The length of the tool axis path L is reflected by the feed rate and the duration generated by the feed rate scheduling algorithm. The duration created by the feed rate scheduling algorithm (adopting the fastest and safest feed rate for the tool path L) is the exact mapping of the NURBS curve without any truncation error and rounding. In the FDI method, the accuracy of the duration τ1-τ7 can be directly reflected on the accuracy of the IPA interpolation parameter u i+1 . The IPA will completely follow the accuracy of the duration.

[0131] For example, if T2 is 230.5 ms, then t i,k is 0.5 ms. If T2 is 230.55 ms, then t i,k is 0.05 ms. t i,k is dynamically adjusted, completely following the accuracy of the duration τ1-τ7 generated by the feed rate scheduling, which theoretically greatly guarantees the accuracy of the interpolation.

[0132] The IPA calculation formula is:

[0133]

[0134] In the formula, k and strlen(strstr(τ i ,".")-1) are the number of decimal points, and str(len-1) is the last digit of the decimal point. len is the length of τ i . In the formula, if the last digit of the decimal point is an integer multiple of 10, i.e. 2 or 5, then t i,k is 2×10 -k or 5×10 -k . This will improve the calculation efficiency. If not, then IPA is t i,k is 10 -k . In addition, only the first derivative of the parameter curve is needed, and the interpolation parameter u i+1 can be obtained by the FDI method. Compared with the STE, the second derivative and the iterative compensation are not needed, reducing the calculation amount and improving the real-time performance of the NURBS interpolator.

[0135] In the embodiment of the present application, in typical tilting table five-axis machine tool machining, such as Figure 3 The kinematic chain of the tilting table five-axis machine tool and the worktable is shown in the kinematic transmission matrix diagram, wherein TX, TY, TZ, TA, and TC are the transmission matrices of the X-axis, the Y-axis, the Z-axis, the A-axis, and the C-axis, respectively. The kinematic transmission matrix TA is related to the rotation direction of the rotating A-axis, as shown in Figure 3 The kinematic transmission matrix TC is the same.

[0136] The geometric center of the tool in the tool coordinate system is [ptx, pty, ptz]T, and the tool orientation vector in the tool coordinate system is [oti, otj, otk]T.

[0137] The transfer matrices for TX, TY, TZ, TA, and TC are as follows:

[0138]

[0139] In the formula, T t It is the tool axis vector.

[0140] In this embodiment of the invention, an FSI method based on FDI is proposed for dual NURBS curves in five-axis machining. Specifically, within the interpolation period, only the interpolation parameter u of the MTM is calculated in real time. i+1,t The interpolation parameters u of the STM can be obtained directly. i+1,o δ t For the chordal error constraint of the tool tip trajectory, δ o The chordal error constraint is applied to the tool axis trajectory. In FSI, feed rate planning and scheduling occur only in MTM, not STM. Therefore, the tool axis interpolation trajectory is not affected by the chordal error δ. o The constraint. To solve this problem, the chordal error constraint δ of STM is applied. o The conversion to MTM constraints ensures the accuracy of the tool axis interpolation trajectory.

[0141] Throughout the machining process, the tool holder trajectory surface is generated by the tool tip trajectory, tool axis trajectory, and tool holder. Due to the interpolation cycle T... s The duration is short, the arc is approximately a chord, and the tool tip interpolation trajectory P i P i+1 Tool axis interpolation trajectory Q i Q i+1 The handle L forms an isosceles trapezoid, which is one face of a regular polyhedron.

[0142] like Figure 4 As shown in the principle of tool axis chord height error constraint in five-axis machining, the tool tip curve P i P i+1 Tool axis curve Q i Q i+1 The trajectory surface formed by the tool holder L is part of a cone. If the tool tip curve is projected onto the plane containing the tool tip, then the tool tip curve and its projection are concentric circles with a central angle Δa. t ,Δa o equal.

[0143] In some embodiments, the computer device includes at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, and the processor implements the steps in any of the above method embodiments when executing the computer program.

[0144] In some embodiments, the computer readable storage medium stores a computer program, and the computer program is executable on a processor to implement the steps in any of the above method embodiments. The computer readable storage medium can be a hard disk or a flash.

[0145] In some embodiments, the information data processing terminal is configured to provide a user input interface to implement the steps in any of the above method embodiments when executed on an electronic device. The information data processing terminal is not limited to a mobile phone, a computer, a switch, or a PC or ARM system available on the market.

[0146] In some embodiments, the server is configured to provide a user input interface to implement the steps in any of the above method embodiments when executed on an electronic device.

[0147] In some embodiments, the computer program product is configured to enable an electronic device to implement the steps in any of the above method embodiments when the computer program product is executed on the electronic device.

[0148] The integrated unit, if implemented in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on this understanding, the present application can implement all or part of the processes in the above embodiments by a computer program to instruct related hardware, and the computer program can be stored in a computer readable storage medium. The computer program is executable on a processor to implement the steps in any of the above method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer readable medium at least includes any entity or device capable of carrying the computer program code to a photographing device / terminal device, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium. For example, U disk, mobile hard disk, magnetic disk or optical disk, etc.

[0149] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in a certain embodiment can be referred to the relevant description of other embodiments.

[0150] In the embodiments of the present application, in order to verify the effectiveness and functionality of the proposed algorithm, experiments are carried out.

[0151] The experimental platform, as shown in Figure 5 , is a numerical control machine tool composed of five axes with a built-in position loop. These axes are controlled by a PC-based CNC system with a real-time Linux operating system and an EtherCAT network. EtherCAT is a real-time industrial Ethernet technology. The command position is transmitted to the axes through the EtherCAT network and object 607A.

[0152] In the experiment, the butterfly angle and S-shaped test pieces are used to show the details of the double NURBS of the FDI method and the FSI method on the five-axis. The performance of the proposed FDI is compared with the second-order Taylor expansion of the feed rate rounding (STE-FR) and the second-order Taylor expansion of the iterative compensation (STE-IC). In the traditional five-axis machining interpolator, the tool axis vector and the tool tip are the same interpolation parameters (SIP), and the FSI is compared with the SIP to verify the perpendicularity of the tool axis vector and the machined surface. The parameter interpolation u i+1 is calculated accurately by the FDI parameter interpolation formula and the IPA formula. In FDI, the increment of the interpolation parameter u with respect to time t is the equation rather than the approximate formula, which theoretically guarantees the accuracy of the interpolation parameter u i+1 . And ti,k is dynamically adjusted, fully following the accuracy of the duration τ1-τ7 generated by the feed rate scheduling, which also theoretically greatly guarantees the accuracy of the interpolation parameter. The position C(u i+1 ) of the next interpolation period is obtained from the NURBS formula.

[0153]

[0154] In the formula, N i,p (u) is the basis function, ω i is the weight, P i is the control point, C(u) is the curve, u is the node vector, and i is the number of control points.

[0155] In the experiment of the present application, as shown in Fig. 6(a), the experiment was carried out to verify the improvement of the butterfly corner in the 6 corners marked as 1-6; as shown in Fig. 6(b), the improvement effect diagram of the first butterfly corner test piece, the elliptical curve trajectory of the present application represents the FDI method of the new type parameter interpolation method proposed by the present application, which is similar to the STE-FR theory approximating the elliptical curve trajectory, and is close to the ideal NURBS curve of the elliptical curve trajectory, and the approaching trapezoidal trajectory line represents the prior art STE-IC method.

[0156] As shown in Fig. 6(c), the improvement effect diagram of the second butterfly corner test piece, the elliptical curve trajectory of the present application represents the FDI method of the new type parameter interpolation method proposed by the present application, which is similar to the STE-FR theory approximating the elliptical curve trajectory, and is close to the ideal NURBS curve of the elliptical curve trajectory, and the straight broken line trajectory line represents the prior art STE-IC method.

[0157] As shown in Fig. 6(d), the improvement effect diagram of the third butterfly corner test piece, the elliptical curve trajectory of the present application represents the FDI method of the new type parameter interpolation method proposed by the present application, which is similar to the STE-FR theory approximating the elliptical curve trajectory, and is close to the ideal NURBS curve of the elliptical curve trajectory, and the straight broken line trajectory line represents the prior art STE-IC method.

[0158] As shown in Fig. 6(e), the improvement effect diagram of the fourth butterfly corner test piece, the elliptical curve trajectory of the present application represents the FDI method of the new type parameter interpolation method proposed by the present application, which is similar to the STE-FR theory approximating the elliptical curve trajectory, and is close to the ideal NURBS curve of the elliptical curve trajectory, and the straight broken line trajectory line represents the prior art STE-IC method.

[0159] As shown in Fig. 6(f), the improvement effect diagram of the fifth butterfly corner test piece, the elliptical curve trajectory of the present application represents the FDI method of the new type parameter interpolation method proposed by the present application, which is similar to the STE-FR theory approximating the elliptical curve trajectory, and is close to the ideal NURBS curve of the elliptical curve trajectory, and the straight broken line trajectory line represents the prior art STE-IC method.

[0160] As shown in Fig. 6(g), the improvement effect diagram of the sixth butterfly corner test piece, the elliptical curve trajectory of the present application represents the FDI method of the new type parameter interpolation method proposed by the present application, which is similar to the STE-FR theory approximating the elliptical curve trajectory, and is close to the ideal NURBS curve of the elliptical curve trajectory, and the straight broken line trajectory line represents the prior art STE-IC method.

[0161] The FDI, prior art STE-IC and STE-FR theory and ideal NURBS are compared. At the selected butterfly angle, it can be obviously seen that the FDI proposed by the present application is closer to the ideal NURBS than the STE-IC, and is similar to the STE-FR. Table 1 gives the chord error data analysis of all six angles of the FDI, STE-IC and STE-FR. The six-angle chord error of the FDI method is obviously smaller than the STE-IC theory, and is almost smaller than the STE-FR.

[0162] Table 1 Chord error data analysis of all six angles of the FDI, STE-IC and STE-FR

[0163]

[0164] As Figure 7 shown, is the schematic diagram for comparing FSI and SIP provided by the embodiment of the present application, the dark area trajectory is the tool axis posture, the lower curve is the tool tip trajectory, and the upper curve is the tool axis trajectory. In order to clearly show the details of FSI and SIP on the double spline curve describing the five-axis machine tool trajectory, part of the dark area trajectory in the S-shaped part is selected to compare the effects of the FSI and SIP methods. As Figure 7 shown, the thick vertical line is the tool posture of the FSI method proposed by the present application, the diagonal line is the tool posture of the SIP, and the thin vertical line is the ideal posture, which is used to compare FSI and SIP. The thick vertical line of the FSI method is closer to the ideal posture than the diagonal line posture of the SIP. The FSI can make the tool axis posture of the FSI almost parallel to the ideal posture, which is more conducive to improving the cutting quality.

[0165] The above describes only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any modification, equivalent replacement and improvement made by those skilled in the art within the technical range disclosed by the present application, which is within the spirit and principle of the present application, should be covered within the protection scope of the present application.

Claims

1. A novel parameter interpolation method for CNC systems, characterized in that, Applied to PC and ARM systems, the method includes the following steps: S1, Feed Rate Scheduling: This schedules the feed rates of the tool tip interpolation speed and the tool axis interpolation speed, transforming the chordal error constraint δ0 of the STM tool axis trajectory into the chordal error constraint δ0 of the MTM tool tip trajectory. t ; Obtain the tool axis feed rate; S2, Interpolation Parameter Accuracy Scheduling: Based on the acquired tool axis feed rate, the interpolation cycle T of the computer numerical control system is adjusted. s Subdivided into interpolation parameter precision t i,k ; S3, based on the interpolation parameter precision t of the subdivision i,k Perform three-axis tool tip FDI parameter interpolation; S4. The tool tip error constraint is combined with the tool axis chord height error constraint model to generate a five-axis chord height error constraint model. Then, the tool tip FDI parameter interpolation under five-axis is combined to obtain the tool axis interpolation trajectory under five-axis. The interpolation formula using the FDI parameter of the tool tip in a five-axis tool path is as follows: In the formula, u i+1,1 It is the (i+1)th interpolation parameter when the last digit of the decimal part is 1, u i+1,2 It is the (i+1)th interpolation parameter when the last digit of the decimal part is 2, u i+1,5 It is the (i+1)th interpolation parameter when the last digit of the decimal part is 5, u i,1 It is the i-th interpolation parameter when the last digit of the decimal part is 1, u i,2 It is the i-th interpolation parameter when the last digit of the decimal part is 2, u i,5 It is the i-th interpolation parameter when the last digit of the decimal part is 5; It is the feed rate at the first IPA when the decimal part ends in 1. It is the feed rate at the second IPA when the decimal part ends in 1. It is the feed rate at the k-th IPA when the decimal part ends in 1. It is the feed rate at the last IPA when the decimal part ends in 1; The IPA precision has the same number of decimal places as the feed rate, and the last digit is 1; ||C'(u i,1 || is the magnitude of the first derivative of the curve when the precision at the end of the IPA is 1; It is the feed rate at the first IPA when the decimal part ends in 2. It is the feed rate at the second IPA when the decimal part ends in 2. It is the feed rate at the m-th IPA when the decimal part ends in 2. It is the feed rate at the last IPA when the decimal part ends in 2; The IPA precision has the same number of decimal places as the feed rate, and the last digit is 2; ||C'(u i,2 || is the magnitude of the first derivative of the curve when the precision at the end of the IPA is 2; It is the feed rate at the first IPA when the decimal part ends in 5. It is the feed rate at the second IPA when the decimal part ends in 5. It is the feed rate at the nth IPA when the decimal part ends in 5. It is the feed rate at the last IPA when the decimal part ends in 5; The IPA precision has the same number of decimal places as the feed rate, and the last digit is 5; ||C'(u i,5 )|| is the magnitude of the first derivative of the curve when the precision at the end of the IPA is 5.

2. The novel parameter interpolation method for CNC systems according to claim 1, characterized in that, In step S1, the feed rate of the tool tip interpolation speed and the tool axis interpolation speed is γ, where γ>1; In the formula, ||C t (u)||,||C o (u)|| represents the total modulus of the tool tip curve and the tool axis curve, respectively, and ||ΔC t (u)||,||ΔC o (u)|| are the modulus lengths of the tool tip curve and the tool axis curve during the interpolation cycle, respectively, C t (u),V t (u) represent the tool tip curve and tool tip feed rate, respectively, C o (u),V o (u) represents the tool axis curve and tool axis feed rate, respectively.

3. The novel parameter interpolation method for CNC systems according to claim 2, characterized in that, In the process of scheduling the feed rate of the tool tip interpolation speed and the tool axis interpolation speed, the relationship between curvature and radius is derived; the curvature k is defined as: In the formula, k is the curvature, Δs is the arc, and Δa is the central angle.

4. The novel parameter interpolation method for CNC systems according to claim 1, characterized in that, In step S1, during the process of obtaining the tool axis feed rate, the chord height error of the tool axis vector mapped to the tool tip interpolation trajectory is: In the formula, δ t It is the chordal error constraint of the tool tip trajectory, u i It is the i-th interpolation parameter, ρ t It is the radius of curvature of the blade tip trajectory. It is the square of the radius of curvature at the blade tip, V t It is the tool tip feed rate, T s ρ is the interpolation cycle, γ is the feed rate between the tool tip interpolation speed and the tool axis interpolation speed, and ρ is the interpolation period. o It is the radius of curvature of the tool axis trajectory. It is the square of the radius of curvature of the tool axis vector curve, V o It is the tool axis vector feed rate, δ o It is the chord error constraint of the tool axis trajectory.

5. The novel parameter interpolation method for CNC systems according to claim 4, characterized in that, The chordal error constraint of the tool tip and tool axis vectors is the chordal error constraint δ of the tool axis trajectory. o The chordal error constraint δ of the tool tip trajectory t The minimum value in is expressed as: d t,o =min(γδ o ,d t ) In the formula, δ t,o It is the common chord height error of the tool tip and the tool axis.

6. The novel parameter interpolation method for CNC systems according to claim 1, characterized in that, In step S2, the IPA calculation formula is: In the formula, t i,k It refers to the interpolation parameter precision, k, and strlen(strstr(τ)). i `,".")-1)` represents the number of decimal points, `str(len-1)` represents the last digit of the decimal point, and `len` is the decimal value. i The length of t; if the last digit of the decimal point is a multiple of 10, i.e., 2 or 5, then t i,k 2×10 -k Or 5×10 -k If not, then t i,k 10 -k .

7. The novel parameter interpolation method for CNC systems according to claim 1, characterized in that, In step S3, the interpolation formula for the FDI parameter of the three-axis tool tip is: In the formula, u i+1 It is the (i+1)th interpolation parameter, u i It is the i-th interpolation parameter, T s It is the interpolation period. It is the feed rate corresponding to the i-th interpolation parameter at the tool tip, t i,k It refers to the interpolation parameter precision, ||C'(u i )|| is the magnitude of the first derivative of the curve.

8. The novel parameter interpolation method for CNC systems according to claim 1, characterized in that, In step S4, the tool shaft chord height error constraint model is as follows: In the formula, δ(u i ) is the chord height error, ρ(u) i ) is curvature, ρ 2 (u i V(u) is the square of the curvature. i ) is the feed rate; The five-axis chord height error constraint model is as follows: d t,o =min(γδ o ,d t ) Where: δ o→t (u i ) is the chord height error mapped from the tool axis to the tool tip surface, ρ t (u i ) is the curvature of the curve at the tip of the knife. It is the square of the radius of curvature at the blade tip, V t (u i T is the tool tip feed rate. s ρ is the interpolation period, γ is the ratio of the arc length of the tool tip curve to the arc length of the tool axis curve, and ρ is the interpolation period. o (u i ) is the curvature of the tool axis curve, V o (u i ) is the tool axis feed rate, δ o (u i ) represents the chord height error of the cutter shaft, δ t,o It is the common chord height error of the tool tip and the tool axis, δ o It is the chordal error constraint of the tool axis trajectory, δ t It is the chordal error constraint of the tool tip trajectory; In five-axis FDI parameter interpolation, the interpolation parameter formula for the double spline of a five-axis CNC machine tool is as follows: In the formula, u i+1,t It is the (i+1)th interpolation parameter of the blade tip, u i,t It is the i-th interpolation parameter of the tool tip, T s It is the interpolation period, N' i,p (u) is a basis function, p i,wx ,p i,wy ,p i,wz All are blade tip control points, o i,wx ,o i,wy ,o i,wz All are tool axis control points, (x, y, z) are the coordinates of the control points, and t i,k Here, n is the interpolation parameter accuracy, w is the number of control points, and u is the workpiece coordinate system. i+1,o It is the (i+1)th interpolation parameter of the tool axis, u i,o It is the i-th interpolation parameter of the tool axis.

9. A novel parameter interpolation system for CNC machining, implementing the novel parameter interpolation method for CNC systems according to any one of claims 1-8, characterized in that, Applied to PC and ARM systems, the system includes: The tool tip trajectory acceleration and deceleration control module is used to perform S-shaped flexible acceleration and deceleration on the tool tip trajectory during cutting; The feed rate scheduling module schedules the feed rates of the tool tip interpolation speed and the tool axis interpolation speed, transforming the chordal error constraint δ0 of the STM tool axis trajectory into the chordal error constraint δ0 of the MTM tool tip trajectory. t ; Obtain the tool axis feed rate; The interpolation parameter accuracy scheduling module is used to schedule the interpolation period T periodically sent by the CNC system. s Subdivided into interpolation parameter precision t i,k ; A three-axis FDI parameter interpolation module is used for interpolation parameter accuracy t based on subdivision. i,k Perform three-axis tool tip FDI parameter interpolation; The tool axis interpolation trajectory acquisition module is used to combine the tool tip point error constraint with the tool axis chord height error constraint model to generate a five-axis chord height error constraint model, and to obtain the five-axis tool axis interpolation trajectory by combining the tool tip FDI parameter interpolation in the five-axis mode.

10. A CNC machining tool, characterized in that, Implement the novel parameter interpolation method for CNC systems as described in any one of claims 1-8.

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