Method for interpolating a machining path of a ruled surface machining based on multiple models and machine tool

Abstract

The application discloses a multi-model-based ruled surface machining path interpolation method and a machine tool. The ruled surface machining path model information is generated based on the ruled surface information of a workpiece. The tool position point trajectory curve in the machining path information is associated with the curve on the ruled surface, and the tool axis point trajectory curve is associated with the curve on the ruled surface. Then, the geometric interpolation is carried out based on the machining path model information, the machining speed is set based on the machining path model information, and the machining speed is set based on the interpolated tool position point after the geometric interpolation. The position information of each physical axis is calculated and stored from the position information and the tool axis vector information of the interpolated tool position point. The interpolation information is arranged into a control command list, and the control command list data is sequentially executed. The interpolation information includes the position information and the machining speed information of each physical axis. The tool axis point trajectory curve, the tool position point and the tool axis point associated function information in the multi-model can be precisely interpolated, the bow height error is eliminated, and the interpolation precision is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of five-axis machine tool processing technology, and in particular to a straight surface machining path interpolation method based on multiple models and a machine tool. BACKGROUND

[0002] The machining equipment in the field of machining usually adopts a numerical control system, and the machining program generated after the machining path and process planning in the CAM software is usually input into the numerical control system in the format of G and M codes. The machining of complex mechanical parts usually requires machining centers to process through turning, milling, drilling and other multi-axis machining processes. The engine impeller is a typical complex part, and the impeller is widely used in the fields of energy, aviation and navigation.

[0003] The five-axis machining program usually contains three-dimensional straight line motion (G1) and circular motion (G2) of the tool position, where the straight line motion or circular motion refers to the motion trajectory of the tool position, and the direction of the tool axis is expressed in the NC program in two ways. One way is to use the three components of the tool axis vector. The other way is to use the angles of the two rotating axes of the five-axis machine tool.

[0004] After the NC program using the tool axis vector expression method is imported into the numerical control system, the program needs to be interpolated in the interpolator of the numerical control system. Because the interpolator of the numerical control system only has the mathematical model of the tool position line segment (such as a circular arc line) and the information of the tool axis vector at the start and end points of the line segment, when the interpolator interpolates the line segment model, there is a lack of a reasonable method for interpolating the tool axis vector. An approximate method is to find a point on the tool axis vector at the start and end points of the line segment, and then perform dense interpolation on the line connecting the two points. The number of interpolation points is consistent with the number of interpolation points of the tool position trajectory line segment, and the direction of the line connecting the corresponding interpolation points is taken as the interpolated tool axis vector. Obviously, there is a bow height error between the shape of the workpiece cut out by this method and the original machining surface, and the existing method is difficult to meet the requirements of higher precision workpieces. SUMMARY

[0005] To solve the above problems, the purpose of the present application is to provide a straight surface machining path interpolation method based on multiple models and a machine tool, which can solve the problem of nonlinear bow height error generated by the interpolation scheme of the prior art.

[0006] The technical scheme provided by the present application is as follows: a straight surface machining path interpolation method based on multiple models, comprising the following steps:

[0007] The machining path model information is generated based on the straight-line machining surface information of the workpiece, and the machining path information includes tool position point trajectory curve model information, tool axis point trajectory curve model information, and information of a tool position point and tool axis point correlation function; wherein the tool position point trajectory curve is associated with an upper curve of the straight-line machining surface, and the tool axis point trajectory curve is associated with a lower curve of the straight-line machining surface.

[0008] Geometric interpolation is performed based on the machining path model information, each machining line segment on the machining path is densified and decomposed into interpolation steps, interpolation step data includes tool position point position information and tool axis vector information, and all interpolation step data is arranged into a list in machining order;

[0009] Machining speed is set based on the machining path model information, and the machining speed is set based on the interpolation tool position point after geometric interpolation;

[0010] Position information of each physical axis is calculated and stored from position information and tool axis vector information of the interpolation tool position point;

[0011] The interpolation information is arranged into a control command list, and control command list data is sequentially executed, and the interpolation information includes position information of each physical axis and machining speed information.

[0012] Preferably, the machining path model information generated based on the straight-line machining surface information of the workpiece further includes determination of the tool axis point trajectory curve:

[0013] If the upper curve and the lower curve of the straight-line machining surface are simple geometric curves of straight lines or circular arcs, the upper curve and the lower curve are offset outward by a tool radius perpendicular to the machining surface; wherein the offset of the circular arc curve is to increase or decrease the radius by a tool radius; the offset upper curve is taken as the trajectory curve of the tool position point, and the offset lower curve is taken as the trajectory curve of the tool axis point;

[0014] If the upper curve and the lower curve of the straight-line machining surface are not simple geometric curves, each straight-line machining surface is first discretized into a combination of straight generators, the upper points and the lower points of each straight generator are offset outward by a tool radius perpendicular to the machining surface, the offset upper points of the straight generator group are fitted as the upper curve, which is taken as the trajectory curve of the tool position point, and the offset lower points of the straight generator group are fitted as the lower curve, which is taken as the trajectory curve of the tool axis point;

[0015] After the offset, the upper curve and the lower curve of adjacent machining line segments need to be transitioned.

[0016] Preferably, the machining path model information generated based on the straight-line machining surface information of the workpiece further includes determination of the tool position point and tool axis point correlation function:

[0017] A mathematical relationship between the arc length position of the tool position point on the trajectory curve and the arc length position of the tool axis point on the trajectory curve is constructed.

[0018] or the discrete correspondence between the arc length position of the tool position trajectory curve and the arc length position of the tool axis trajectory curve is expressed in the form of a list.

[0019] Preferably, the mathematical relationship between the arc length of the tool position trajectory curve and the tool axis trajectory curve is constructed by dividing the tool position trajectory curve and the tool axis trajectory curve into equal parts, and then constructing the mathematical relationship between the arc length of each part of the tool position trajectory curve and the tool axis trajectory curve.

[0020] Preferably, the method further comprises: at the corner, the tool position trajectory degenerates into a point, and in the list, the tool position trajectory at the corner corresponds to a segment of the tool axis trajectory curve arc length, and the interpolation uses an arc angle step.

[0021] Preferably, the method further comprises:

[0022] The CAM module expresses the line segment of the generated machining path in a line segment class or structure of an object-oriented programming language, and the entire machining path can be expressed by a list of objects of the line segment class or structure, and a member variable of the line segment class or structure representing the type of line segment is used to distinguish between machining lines, cutting-in and cutting-out lines, and fast-forward lines, a member variable of the line segment class or structure representing the machining speed is used to express the theoretical machining speed, one or more member functions of the line segment class or structure expressing the mathematical model of the geometric curve are used to express the tool position trajectory curve function, one or more member functions of the line segment class or structure expressing the mathematical model of the geometric curve are used to express the tool axis trajectory curve function, and one or more member functions of the line segment class or structure expressing the mathematical model of the correlation function are used to express the correlation function; the interpolation module obtains the machining path model information by sharing memory with the CAM module;

[0023] Alternatively, the machining path model information is transmitted from the CAM module to the interpolation module by passing the modeling parameters, which include the general parameters of the path line segment, the model parameters of the tool position trajectory curve, and the model parameters of the tool axis trajectory curve. The machining path model information expressed by the modeling parameters can be transmitted through a text file or other data interaction mode, and the machining path model information includes the tool position and tool axis point information at the origin of the machining path.

[0024] Preferably, the machining speed setting based on the machining path model information further comprises:

[0025] The process model is called based on the machining path information to calculate the theoretical machining speed for each segment of the machining path line segment and the end point of the path line segment;

[0026] The process model comprises a function relationship taking the curvature variation of the path line segment curve as the independent variable and the processing speed as the dependent variable, the greater the curvature variation of the path line segment curve, the slower the speed, the greater the change of the path direction of the adjacent two line segments in calculating the speed of the end point of the path line segment, the slower the speed.

[0027] Preferably, the method further comprises:

[0028] A zero-length line segment is added at each line segment connection point, and the theoretical processing speed of the connection point with the zero-length line segment as the connection point reflects the change of the tangential direction of the adjacent line segments of the connection point, the greater the change of the tangential direction, the smaller the theoretical processing speed of the connection point, and the connection point can also realize the transition of the tool axis vector direction of the adjacent line segments of the connection point.

[0029] And / or, a transition circular arc is inserted at the connection point where the tangential direction of the processing path changes by more than a threshold value.

[0030] Preferably, the method further comprises:

[0031] Geometric interpolation is performed: the interpolation step is determined according to an interpolation period and a theoretical processing speed, or the interpolation step is determined according to control accuracy, and then the number of interpolation periods required for the interpolation step is calculated according to the interpolation period and the theoretical processing speed; wherein for the zero-length line segment, the interpolation step represents an arc angle of the change of the tool axis direction within an interpolation period or an arc angle determined according to the arc angle control accuracy.

[0032] The interpolation step is used to divide the tool position point trajectory curve of the processing path to obtain interpolation tool position points, and for the zero-length line segment, the arc angle of the change of the tool axis direction is divided.

[0033] The interpolation points on the tool axis point trajectory curve are found through a tool position point and a tool axis point association function to obtain the tool axis point coordinates and tool axis vector information corresponding to the interpolation tool position points.

[0034] The interpolation point data is expressed by a step class or a structure of an object-oriented programming language, and the entire interpolated processing path is expressed by an object list of the step class or the structure.

[0035] The object list of the step class or the structure is subjected to speed interpolation: according to the acceleration limit of the machine, the acceleration limit of the specific process, and the acceleration and deceleration model, the theoretical processing speed on the path line segment of the tool position point is taken as the maximum value, the theoretical processing speed of the end point of the path line segment is taken as the starting point, and the continuous and smooth processing speed is taken as the target to gradually adjust the theoretical processing speed corresponding to each interpolation tool position point in the direction of the midpoint of the path line segment, and the adjusted processing speed is stored in the object list of the step class or the structure as a member variable of the step class or the structure.

[0036] Preferably, for the case of interpolation inside the CAM or the interpolation module sharing memory with the CAM module, the associated function can be obtained from one or several member functions of the line segment class or structure representing the associated function mathematical model; for the case of interpolation outside the CAM, the associated function is limited to the case of equal division; for the zero-length tool position line segment, the associated function is not needed, and the tool axis point is determined by the arc angle interpolation step, which is irrelevant to the tool position; for the case of tool axis point trajectory curve degenerating into a point, the associated function is not needed to determine the tool axis point.

[0037] Preferably, the method further comprises: if the machining path model information is transmitted from the CAM module to the interpolation module in the form of modeling parameters, restoring the modeling parameters to a mathematical model in the interpolation module.

[0038] Preferably, the method further comprises: if the interpolation module does not share memory with the control execution module, transmitting the interpolated step list data to the control execution module through data communication or text file data interaction.

[0039] Preferably, when generating the machining path model information based on the straight-line machining surface information of the workpiece, it is also necessary to calculate the offset amount that needs to be compensated based on a predicted mathematical model and preset process parameters, the predicted mathematical model including but not limited to one or more of a cutting speed model, a kerf taper model, a rear drag amount model, and a machine tool random error model established based on machining mechanism, and the initial tool axis vector after offset is optimized according to the offset amount to effectively compensate for errors caused in the machining process:

[0040] A first predicted mathematical model is called to calculate the rear drag amount generated by cutting the workpiece according to the target parameter information of the current position point, and then a first angle needed to swing along the cutting feed direction is calculated for reverse compensation;

[0041] The first component of the initial tool axis vector along the cutting feed direction is obtained, and the first component is optimized according to the first angle to obtain the second component of the optimized tool axis vector along the cutting feed direction;

[0042] A second predicted mathematical model is called to calculate the lateral taper generated by cutting the workpiece according to the target parameter information of the current position point, and then a second angle needed to swing along the perpendicular direction of the cutting feed direction is calculated for reverse compensation;

[0043] The third component of the initial tool axis vector along the perpendicular direction of the cutting feed direction is obtained, and the third component is optimized according to the second angle to obtain the fourth component of the optimized tool axis vector perpendicular to the cutting feed direction;

[0044] The final optimized tool axis vector is synthesized according to the values of the second component and the fourth component.

[0045] The application also provides a machine tool based on the same concept, comprising:

[0046] A machining path generation module is configured to generate machining path model information based on workpiece ruled surface information, wherein the machining path information comprises tool position point trajectory curve model information, tool axis point trajectory curve model information, and information of a tool position point and tool axis point correlation function; wherein the tool position point trajectory curve is associated with a curve on the ruled surface, and the tool axis point trajectory curve is associated with a curve below the ruled surface.

[0047] A geometry interpolation module is configured to perform geometry interpolation, to divide each machining path segment on the machining path into interpolation steps, and to arrange data of all interpolation steps into a list according to a machining sequence.

[0048] A speed setting module is configured to set machining speed based on the interpolation tool position points after geometry interpolation.

[0049] An inverse solution calculation module is configured to calculate position information of each physical axis from a tool axis vector of the interpolation tool position points and to store the position information.

[0050] An execution module is configured to arrange the interpolation information into a control command list and to sequentially execute control command list data.

[0051] The application also provides an electronic device based on the same concept, comprising:

[0052] A memory is configured to store a processing program.

[0053] A processor is configured to implement the multi-model based ruled surface machining path interpolation method of any one of the above aspects when executing the processing program.

[0054] The application also provides a readable storage medium having a processing program stored thereon, wherein the processing program is executed by a processor to implement the single-image based high-precision human head reconstruction method of any one of the above aspects.

[0055] The application has the following advantages and positive effects compared with the prior art due to the above technical solutions:

[0056] 1. The technical solution of this embodiment introduces the tool position point trajectory curve, the tool axis point trajectory curve, and the tool position point and tool axis point correlation function into the processing path information before interpolation is performed. That is to say, there are both mathematical models of the tool position point and the tool axis point, and the tool position point and tool axis point mathematical models are simultaneously transmitted to the interpolation module. Compared with the existing technology that processes only based on the tool position point mathematical model, the interpolation module of this embodiment subsequently incorporates the tool axis point trajectory curve, the tool position point and tool axis point correlation function into the processing process when performing theoretical processing speed calculation, geometric interpolation and speed interpolation. The model information is more complete, which can avoid the occurrence of bow height error and improve the processing accuracy of the workpiece.

[0057] 2. The present invention adopts an iterative interpolation method, that is, based on the introduced tool position point trajectory curve, tool axis point trajectory curve, tool position point and tool axis point correlation function, process parameter model, etc., geometric interpolation is first performed, and then the speed of the interpolated short line segment is set. Here, a speed model that can adapt to the continuous change of line segment characteristics (such as change in movement direction) is required. When performing the next step of process parameter interpolation, a set of process parameter models (cutting seam taper model, drag amount model, etc.) that can adapt to the change of line segment characteristics and continuous change of speed are required. Therefore, in the entire processing program, the process parameters can change with the actual working conditions, and the interpolation accuracy is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein:

[0059] Figure 1 A schematic diagram for generating machining paths in CAM software;

[0060] Figure 2 Schematic diagram of the process flow of the multi-model based ruled surface machining path interpolation method of the present invention;

[0061] Figure 3 Schematic diagram of an embodiment in which the tool position point trajectory degenerates into a point at a corner;

[0062] Figure 4 This is an example of the tool location path and theoretical processing speed;

[0063] Figure 5 An example of velocity distribution after interpolation. DETAILED DESCRIPTION

[0064] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are greatly simplified and not to exact ratios, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0065] It should be noted that all direction indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, motion condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the direction indications will also change accordingly.

[0066] First embodiment

[0067] Referring to Figure 2 The embodiment provides a ruled surface machining path interpolation method based on a multi-model, which comprises the following steps:

[0068] Generating machining path model information based on workpiece ruled surface information, wherein the machining path information comprises tool position point trajectory curve model information, tool axis point trajectory curve model information and information of a tool position point and tool axis point correlation function; wherein the tool position point trajectory curve is associated with an along curve on the ruled surface, and the tool axis point trajectory curve is associated with an under curve on the ruled surface;

[0069] Performing geometric interpolation based on the machining path model information, and densifying and decomposing each machining line segment on the machining path into an interpolation step, wherein interpolation step data comprises tool position point position information and tool axis vector information, and data of all interpolation steps are arranged into a list according to a machining sequence;

[0070] Setting a machining speed based on the machining path model information, and setting the machining speed based on the interpolation tool position point after geometric interpolation;

[0071] Calculating and storing position information of each physical axis from position information and tool axis vector information of the interpolation tool position point;

[0072] Arranging the interpolation information into a control command list, and sequentially executing control command list data, wherein the interpolation information comprises position information of each physical axis and machining speed information.

[0073] The technical scheme of the embodiment introduces a tool position point trajectory curve, a tool axis point trajectory curve and a tool position point and tool axis point correlation function into machining path information before interpolation, that is, there are mathematical models of tool position points and tool axis points, and the mathematical models of tool position points and tool axis points are simultaneously transmitted to an interpolation module, compared with the prior art which only processes according to a mathematical model of tool position points, the tool axis point trajectory curve and the tool position point and tool axis point correlation function are also included in the processing process when the interpolation module subsequently calculates a theoretical machining speed, performs geometric interpolation and speed interpolation, the model information is more perfect, and the generation of a sag error can be avoided, and the machining precision of a workpiece is improved.

[0074] Referring to Figure 1 Taking a machining path generated by a CAM software for the workpiece shown in FIG. 1 as an example. Figure 1 Taking a machining path generated by a CAM software for the workpiece shown in FIG. 1 as an example.Figure 1 wherein A represents the start and end of the path, L represents the fast feed line, M represents the discrete and offset busbar, and R represents the cut-in and cut-out line.

[0075] Preferably, the generating the machining path model information based on the straight-line machining surface information of the workpiece further comprises determining the tool axis point trajectory curve:

[0076] If the upper curve and the lower curve of the straight-line machining surface are simple geometric curves of straight lines or circular arcs, offset the upper curve and the lower curve outward by a tool radius perpendicular to the machining surface; wherein the offset of the circular arc curve is to increase or decrease the radius by a tool radius; the offset upper curve is taken as the tool position point trajectory curve, and the offset lower curve is taken as the tool axis point trajectory curve;

[0077] If the upper curve and the lower curve of the straight-line machining surface are not simple geometric curves, first discretize each straight-line machining surface into a combination of straight busbars, offset the upper point and the lower point of each straight busbar outward by a tool radius perpendicular to the machining surface, fit the offset upper points of the straight busbar group as the upper curve as the tool position point trajectory curve, and fit the offset lower points of the straight busbar group as the lower curve as the tool axis point trajectory curve;

[0078] After the offset, the upper curve and the lower curve of adjacent machining line segments need to be transitioned.

[0079] In this embodiment, the lower points of the offset straight busbar group are fitted as the lower curve as the tool axis point trajectory curve, and after obtaining the tool axis point trajectory curve, it is sent to the interpolation module together with other information in the model, so that the interpolation accuracy of the interpolation module is higher. The information contained in the model also includes: machining path tool position point (TCP) trajectory curve, tool axis point trajectory curve, tool position point and tool axis point position correlation function, machine tool structure model parameters, process parameter model, interpolation period parameters, control accuracy parameters, etc. Among them, the tool position point and tool axis point position correlation function refers to the distribution rule of the tool position point and tool axis point on the trajectory curve. A simplest correlation function example is equal division. Generally, the correlation function refers to the mathematical relationship between the arc length position of the tool position point on its trajectory curve and the arc length position of the tool axis point on its trajectory curve. The correlation function that does not form a mathematical rule can also be expressed in the form of a list. For Figure 3 In the case shown, the tool position point trajectory degenerates into a point at the corner, and the tool axis point trajectory curve can be a circular arc curve formed by points 1-2-3-4-5, or a straight line formed by points 1'-2'-3'-4'-5', or other types of curves, but because the arc length of the tool position point trajectory curve is zero, the correlation function cannot correlate the arc length position of the tool position point on its trajectory curve with the arc length position of the tool axis point on its trajectory curve, at this time the correlation function is not needed, and the arc angle step can be used for interpolation. As shown in Figure 3Conversely, in the case of a corner, the tool axis point trajectory degenerates to a point, but there is also the possibility that the trajectory curve of the tool position point exists. At this time, the association function is also unnecessary because the position of the tool axis point is determined. Different processing techniques use different models, such as water jet cutting, which includes cutting speed models, cutting seam taper models, and trailing amount models; laser processing, which includes cutting parameter models, perforation parameter models, and laser power / frequency curves; and milling processing, which includes processing speed models, acceleration models, jerk models, feed amount models, and cutting force models.

[0080] Specifically, generating the machining path information based on the straight-line machining surface information of the workpiece also includes determining the tool position point and tool axis point association function:

[0081] Constructing a mathematical relationship between the arc length position of the tool position point on the trajectory curve and the arc length position of the tool axis point on the trajectory curve;

[0082] Or expressing the discrete corresponding relationship between the arc length position of the tool position point on the trajectory curve and the arc length position of the tool axis point on the trajectory curve through a list.

[0083] By establishing the association function between the tool position point and the tool axis point, the position and attitude of the tool can be accurately and synchronously controlled, ensuring that the relative motion of the tool and the workpiece during machining meets the machining requirements. The determination of the association function can be a continuous mathematical relationship or a discrete list correspondence, and this flexibility allows the machining strategy to be optimized according to the actual machining situation to adapt to complex machining tasks.

[0084] Preferably, a mathematical relationship between the tool position point trajectory curve and the tool axis point trajectory curve arc length is constructed, and by equally dividing the tool position point trajectory curve and the tool axis point trajectory curve, a mathematical relationship between each equally divided tool position point trajectory curve and tool axis point trajectory curve arc length is constructed.

[0085] By establishing an accurate mathematical relationship, the synchronous movement of the tool position point and the tool axis point during machining can be ensured, which is crucial for maintaining machining precision, especially in complex five-axis machining. Equally dividing the trajectory curve and establishing the arc length relationship can optimize the tool path, reduce unnecessary movement, and thus shorten the machining time and improve production efficiency. By accurately controlling the positions of the tool position point and the tool axis point, machining errors caused by inaccurate tool positioning can be reduced, and the dimensional accuracy and surface quality of the machined parts can be improved.

[0086] Preferably, the method further comprises: at a corner, the tool position point trajectory degenerates to a point, and in the list, the tool position point trajectory at the corner corresponds to a segment of the tool axis point trajectory curve arc length, and an arc angle step is used during interpolation.

[0087] When the tool position point trajectory at the corner degenerates into a point, using arc angle step for interpolation can better simulate the actual trajectory of the tool at the corner, further improving the machining precision. Using arc angle step for interpolation at the corner can make the tool movement smoother, reducing the machining defects caused by incoherent tool movement.

[0088] Preferably, generating the machining path model information based on the straight-line surface information of the workpiece further comprises:

[0089] The CAM module expresses the generated machining path line segments in a line segment class or structure of an object-oriented programming language, and the entire machining path can be expressed by a list of objects of the line segment class or structure, and the machining line, the cutting-in and cutting-out line, and the fast-forward line are distinguished by a member variable of the line segment class or structure representing the line segment type, the theoretical machining speed is expressed by a member variable of the line segment class or structure representing the machining speed, the tool position point trajectory curve function is expressed by one or more member functions of the line segment class or structure representing the mathematical model of the geometric curve, the tool axis point trajectory curve function is expressed by one or more member functions of the line segment class or structure representing the mathematical model of the geometric curve, and the correlation function is expressed by one or more member functions of the line segment class or structure representing the mathematical model of the correlation function; the interpolation module obtains the machining path model information by sharing memory with the CAM module;

[0090] Alternatively, the machining path model information is transmitted from the CAM module to the interpolation module by passing modeling parameters, and the modeling parameters include general parameters of the path line segments, model parameters of the tool position point trajectory curve, and model parameters of the tool axis point trajectory curve. The machining path model information expressed by the modeling parameters can be transmitted through a text file or other data interaction mode, and the machining path model information to be transmitted includes the tool position point and tool axis point information at the origin of the machining path.

[0091] By using an object-oriented programming language to express the machining path, accurate machining path planning and control can be achieved, thereby optimizing the machining process and improving efficiency. When the machining path information is transmitted by modeling parameters, the correlation function of the tool position point trajectory curve and the tool axis point trajectory curve is applicable.

[0092] For example, each line segment of the generated machining path is expressed by a C++ class Entity, and the entire machining path can be expressed by a list of C++ Entity objects list <entity>To express, the Entity class member variable processing quality level m_dQuality is used to distinguish processing lines, cutting-in and cutting-out lines, fast-forward straight lines;

[0093] For example, 1-5 is a 5-level processing quality, 9 is a cutting-in and cutting-out line, 10 is a fast-forward idle line, and 13 is an idle transition line.

[0094] The processing path information is obtained through shared memory, or the processing path information is expressed through a text file, and the text file contains general parameters of path line segments, parameters of tool position NURBS spline curves, and parameters of tool axis NURBS spline curves. The text file (usually in the first line) provides tool position and tool axis information at the processing path origin: m_StartPt_TCP_X, m_StartPt_TCP_Y, m_StartPt_TCP_Z, m_StartPt_Axis_X, m_StartPt_Axis_Y, m_StartPt_Axis_Z.

[0095] If the interpolation module is placed inside the CAM software, the interpolation module can directly obtain the above path information. An example of the Entity class is as follows:

[0096]

[0097]

[0098]

[0099] If the interpolation module is placed outside the CAM software but on the same computer, the interpolation module can obtain the above path information through shared memory. If it is not on the same computer, the processing path information can be expressed through a text file, for example, the following example uses three lines in the text file

[0100] (They can also be combined into one line. The three lines are for easy reading and viewing) to express the information of a segment of processing path line segments. The entire processing path is a combination of the information of the above single segment processing path line segments.

[0101] The first line: m_nEntityNo, m_dQuality, m_dThickness, m_nOffset

[0102] Second line: m_nEntityType_TCP,m_EPt_TCP_X,m_EPt_TCP_Y,m_EPt_TCP_Z,m_dRadius_TCP,m_dLength_TCP,{P; (X,Y,Z,R;X,Y,Z,R;...;X,Y,Z,R;X,Y,Z,R);(K;...K)};

[0103] The third line: m_nEntityType_Axis,m_EPt_Axis_X,m_EPt_Axis_Y,m_EPt_Axis_Z,m_dRadius_Axis,m_dLength_Axis,{P; (X,Y,Z,R;X,Y,Z,R;...;X,Y,Z,R;X,Y,Z,R);(K;...K)};

[0104] The parameters in the first line are common parameters of the path segment, which can be defined by referring to the example of the Entity class above.

[0105] The parameters in the second line, except for those enclosed in {}, can also be defined as in the Entity class example above. When m_nEntityType_TCP is 4, the parameters enclosed in {} are used instead. The parameters enclosed in {} represent the parameters of the tool point NURBS spline curve (P is the level of the NURBS spline curve, X / Y / Z in the first () are the coordinates of the control point, R is the weight of the control point, and the number of control points must be at least equal to the number of levels; K in the second () is the node vector parameter, and the number of node vector parameters must be equal to the number of control points plus the level).

[0106] The parameters in the third line, except for those enclosed in {}, can also be defined as in the Entity class example above. The parameters enclosed in {} are only used when m_nEntityType_Axis is 4. The parameters enclosed in {} represent the parameters of the NURBS spline curve of the tool axis point.

[0107] The text file (usually in the first line) should give the tool position point and tool axis point information at the origin of the machining path: m_StartPt_TCP_X, m_StartPt_TCP_Y, m_StartPt_TCP_Z, m_StartPt_Axis_X, m_StartPt_Axis_Y, m_StartPt_Axis_Z.

[0108] First import the path information in the text file into an Entity list <entity>and then passed to the interpolation module.

[0109] If the machining path model information is passed from the CAM module to the interpolation module in the form of modeling parameters, the modeling parameters are restored to the mathematical model in the interpolation module.

[0110] Preferably, the machining speed setting based on the machining path model information further comprises:

[0111] The process model is called based on the machining path information to calculate the theoretical machining speed for each machining path line segment and the end point of the path line segment, the machining path information at least including information of the change of process parameters such as thickness information obtained by calculating the distance between the tool position point and the tool axis point or by the workpiece thickness parameter;

[0112] The process model includes a function relationship with the change of curvature of the path line segment curve as the independent variable and the machining speed as the dependent variable, the greater the change of curvature of the path line segment curve, the slower the speed, and the greater the change of path direction of the adjacent two line segments, the slower the speed when calculating the speed of the end point of the path line segment.

[0113] Since the technical solution of the present application introduces the tool position point trajectory curve, the tool axis point trajectory curve, and the tool position point and tool axis point correlation function, the thickness information of the cutting is the distance between the upper and lower points of the generatrix, the actual cutting thickness is used to control the machining speed, and the change of curvature of the path curve and the change of path direction of the adjacent two line segments are used to jointly control the theoretical machining speed, so that the determination of the theoretical machining speed under the technical concept of the present application is more in line with the workpiece working condition, and the machining precision is higher. The use of the process model enables the system to adapt to different machining conditions and workpiece materials, improving the flexibility and adaptability of the machining system.

[0114] Preferably, the method further comprises:

[0115] A zero-length line segment is added at each line segment connection point, and a theoretical machining speed of the connection point reflects the change of the tangential direction of the adjacent line segments, the greater the change of the tangential direction, the smaller the theoretical machining speed of the connection point, and the connection point can also realize the transition of the tool axis vector direction of the adjacent line segments;

[0116] And / or, a transition arc is inserted at the connection point where the machining path tangential direction changes by more than a threshold value. To improve the smoothness of the motion speed, acceleration, and jerk, suppress vibration and jitter, and improve machining efficiency. For high-speed high-precision machining applications (such as laser cutting machining), it is necessary to insert a transition arc at the connection point where the machining path tangential direction changes greatly to improve the smoothness of the motion speed, acceleration, and jerk, suppress vibration and jitter, and improve machining efficiency.

[0117] Preferably, the method further comprises:

[0118] Carrying out geometric interpolation: determining an interpolation step, which is calculated according to an interpolation period and a theoretical machining speed; or, determining an interpolation step according to control precision, and then calculating the number of interpolation periods required by the interpolation step according to the interpolation period and the theoretical machining speed; wherein for a zero-length line segment, the interpolation step represents an arc angle of change in the tool axis direction within one interpolation period or an arc angle determined according to arc angle control precision;

[0119] Segmenting the machining path tool position trajectory curve using the interpolation step to obtain interpolation tool positions, and for a zero-length line segment, segmenting the arc angle of change in the tool axis direction;

[0120] Finding interpolation points on the tool axis point trajectory curve through a tool position and tool axis point association function to obtain tool axis point coordinates and tool axis vector information corresponding to the interpolation tool positions; wherein for interpolation within the CAM, the association function can be obtained from the Entity class; for interpolation outside the CAM, the association function can be limited to the case of equal division; for a zero-length tool position line segment, no association function is required, and the tool axis point is determined by the arc angle interpolation step and is independent of the tool position; for the case where the tool axis point trajectory curve degenerates into a point, no association function is required to determine the tool axis point;

[0121] Interpolation point data is expressed using a step class or structure of an object-oriented programming language, and the entire interpolated machining path is expressed using an object list of the step class or structure;

[0122] Carrying out speed interpolation on the object list of the step class or structure: according to the acceleration limit of the machine, the acceleration limit of a specific process, and the acceleration and deceleration model, taking the theoretical machining speed on the tool position path line segment as the maximum value, taking the theoretical machining speed at the end point of the path line segment as the starting point, and taking the goal of obtaining continuous and smooth machining speed as the target, adjusting the theoretical machining speed corresponding to each interpolation tool position step by step in both directions towards the midpoint of the path line segment, and storing the adjusted machining speed as a member variable of the step class or structure into the object list of the step class or structure.

[0123] For example, interpolation point data is stored in the list list <pathstep>;

[0124] Here PathStep is a C++ class, which contains the interpolation information of each interpolation point. The following is an example of PathStep class:

[0125]

[0126] In the step of geometry interpolation, the interpolation information is mainly the geometry information of interpolation point (m_StepPtS, m_StepPtE, m_nEntityNo, m_dOrientAngle, m_dLength, m_bDrive, m_sDrive).

[0127] Carrying out velocity interpolation: according to the acceleration limit of machine, the acceleration limit of specific process and the acceleration-deceleration model, the theoretical machining speed on the tool position path is targeted, the theoretical machining speed of the path endpoint is taken as the starting point, and the theoretical machining speed corresponding to each interpolation tool position is adjusted step by step in the direction of the path midpoint, so that the continuous and smooth machining speed is obtained.

[0128] The acceleration-deceleration model is, for example, trapezoidal acceleration-deceleration, trigonometric function acceleration-deceleration, exponential acceleration-deceleration, S-shaped curve acceleration-deceleration, cubic polynomial acceleration-deceleration, etc. Figure 4 For an example of a tool position path, there are different theoretical machining speeds in different path segments. Figure 5 For an example of the interpolation velocity distribution, the simplest trapezoidal acceleration-deceleration is adopted here, and the S-shaped curve acceleration-deceleration or other acceleration-deceleration models can improve the smoothness of the velocity. Since acceleration-deceleration requires time, for shorter path segments, the theoretical machining speed may not be reached. In the step of velocity interpolation, the interpolation information is saved in (m_dSpeed, m_bDelay, m_sDelay), and here the delay amount Delay is calculated from m_dSpeed and m_dLength.

[0129] The present application adopts the method of iterative interpolation, that is, based on the introduced tool position trajectory curve, tool axis point trajectory curve, tool position and tool axis point correlation function, process parameter model, etc., geometry interpolation is carried out first, and then velocity is set for the short and small line segment after interpolation. Here, a velocity model that can adapt to the continuous change of line segment characteristics (such as change of motion direction) is needed, and a set of process parameter models (seam taper model, trailing amount model, etc.) that can adapt to the change of line segment characteristics and the continuous change of velocity are needed when carrying out the next step of process parameter interpolation, so that the process parameters can change with the actual working condition in the whole machining program, and the interpolation accuracy is higher.

[0130] Further, the IO command is inserted, for a specific machining process, according to the attribute of the machining path, the corresponding IO control command is inserted at the appropriate interpolation tool position, such as: for water jet cutting, the high pressure pump on / off command, the nozzle on / off command, the abrasive on / off command. In this step, the interpolation information is saved in (m_bIO, m_sIO).

[0131] For a specific machining process, preferably referring to Figure 2 A process parameter interpolation step can be added, the process related parameters are calculated at the interpolation tool position. If necessary, the tool position and tool axis vector are adjusted, or the process parameters are adjusted. For example: for water jet cutting, according to the kerf taper model and the trailing edge model and the current interpolation step speed, the current jet taper (m_dTE) and the jet trailing edge (m_dJL) are calculated at the interpolation tool position. If the tool axis inclination causes substantial changes in the actual cutting thickness, the cutting speed (m_dSpeed) also needs to be adjusted. For milling finishing, according to the workpiece three-dimensional model and the tool three-dimensional model, and the current interpolation step machining speed, feed, cutting depth, the current cutting force and the deformation between the tool and the workpiece are calculated at the interpolation tool position, and the position of the tool position is adjusted according to the deformation; for laser cutting, according to the laser power / frequency curve and the current interpolation step speed, the current power / frequency is calculated at the interpolation tool position, and the output laser power / frequency is adjusted.

[0132] Preferably, when generating the machining path model information based on the straight surface information of the workpiece, the offset amount that needs to be compensated is also calculated based on the predicted mathematical model and the preset process parameters, and the predicted mathematical model includes but is not limited to one or more of the cutting speed model, the kerf taper model, the trailing edge model and the machine tool random error model established based on the machining mechanism, and the initial tool axis vector after the offset is optimized according to the offset amount to effectively compensate the error caused in the machining process:

[0133] The first predicted mathematical model is called, the trailing edge generated by cutting the workpiece is calculated according to the target parameter information of the current position point, and then the first angle that needs to be swung along the cutting feed direction is calculated to perform reverse compensation;

[0134] The first component of the initial tool axis vector along the cutting feed direction is obtained, and the first optimization is performed according to the first angle, and the second component result of the optimized tool axis vector along the cutting feed direction is obtained;

[0135] The second predicted mathematical model is called, the lateral taper generated by cutting the workpiece is calculated according to the target parameter information of the current position point, and then the second angle that needs to be swung along the perpendicular direction of the cutting feed direction is calculated to perform reverse compensation;

[0136] obtaining a third component of the initial tool axis vector along a direction perpendicular to the cutting feed direction, and performing a second optimization according to the second angle to obtain a fourth component of the optimized tool axis vector perpendicular to the cutting feed direction;

[0137] According to the values of the second component and the fourth component, a final optimized tool axis vector is synthesized.

[0138] The calling of the prediction mathematical model comprises the following steps:

[0139] Determine the current cutting speed in the water jet cutting scenario;

[0140] According to the mathematical model corresponding to the ruled surface and the preset machining process parameters, the cutting speed of each point on the cutting path is calculated

[0141] Wherein, v is the cutting speed, Nm is the material machinability parameter, Pw is the water pressure, is the water flow, is the abrasive flow, Cs is the proportional factor, q is the cutting quality level, H is the material thickness, and D is the jet beam diameter. In the embodiments of the present application, the specific values of Pw, D superscript corresponding to the specific values are not limited in the embodiments of the present application, and the specific values in the above formula are only examples.

[0142] The calling of the first prediction mathematical model comprises the following steps:

[0143] Obtain the current cutting speed, and combine the material thickness, material type and process parameter information of the current position point to calculate the after-drag generated by water jet cutting. The formula is as follows:

[0144]

[0145] Wherein, J(h) is the after-drag, P is the water pressure, is the abrasive flow, h is the cutting depth, and v is the cutting speed. In the embodiments of the present application, the fixed values of each parameter can be determined in advance according to requirements or tests, and the specific values in the above formula are only examples.

[0146] The calling of the second prediction mathematical model comprises the following steps:

[0147] Obtain the current cutting speed and material thickness, and calculate the current lateral taper angle:

[0148]

[0149] Wherein, TA is the lateral taper generated by cutting, V is the cutting speed, H is the thickness of the cut material at the current cutting point. In the embodiments of the present application, the fixed values of the parameters can be determined according to requirements or tests, and the present application is not limited thereto, and the specific values in the above formula are only examples.

[0150] The core idea of the present application is to interpolate and optimize the machining path of the straight machining surface based on multiple models, to comprehensively consider the iterative interpolation of the geometric model and the speed model, the optimal adjustment of the tool axis by the process adjustment mathematical model, and the like based on the tool position point trajectory curve model, the tool axis point trajectory curve model, and the tool position point and tool axis point correlation function, to optimize the above multiple models, and to improve the control precision of the interpolation and reduce the machining error.

[0151] In one embodiment, the determination of the initial tool axis vector according to the generatrix of the straight machining surface or the preset cutting direction comprises: if the upper curve and the lower curve of the straight machining surface are simple geometric curves, offsetting the upper curve and the lower curve outward perpendicularly to the machining surface by a tool radius; if the upper curve and the lower curve of the straight machining surface are not simple geometric curves, discretizing each straight machining surface into a combination of straight generatrices; offsetting the straight generatrix combination outward perpendicularly to the machining surface by a tool radius, fitting the upper points of the offset straight generatrix combination as the upper curve as the trajectory curve of the tool position point, and fitting the lower points of the straight generatrix combination as the lower curve as the trajectory curve of the tool axis point. If the upper curve or the lower curve is a simple geometric curve, the parameter equation thereof can be determined directly by using the existing function expression as the mathematical model thereof without curve fitting. The mathematical model of the simple geometric curve is a special case of a circular arc, and the parameter equation of the circular arc is x(u) = cos(u), y(u) = sin(u). If the upper curve or the lower curve is not a simple geometric curve but a complex curve, curve fitting is required, and any available method can be used for curve fitting of the upper curve and the lower curve to obtain the mathematical model thereof, and the present application is not limited thereto. The mathematical model of the complex curve is a parameter equation of a NonUniform Rational B-Splines (NURBS) curve. As can be seen from the above analysis, in the present application, the mathematical model of the upper curve and the mathematical model of the lower curve can correspond to a straight line or a circular arc or a spline curve, or can correspond to other one or a group of complex functions, or can correspond to a database, and the like. Moreover, in actual application, the upper curve and the lower curve corresponding to the same straight machining surface can be the same or different, and the present application is not limited thereto.

[0152] Further, the machine tool inverse solution motion algorithm calculates the position information of each physical axis from the tool axis vector of the interpolated tool position point. The position information can be incremental or absolute. The interpolation information is saved in (m_StepPtS, m_StepPtE, m_bDrive, m_sDrive).

[0153] To reduce the data volume, a data compression step can be added. In the interpolation step data list generated in the above step, adjacent interpolation steps with the same data are found and merged into one repeated interpolation step. The repetition information is saved in (m_bRepeat, m_sRepeat).

[0154] The above interpolation information (m_bIO, m_bDrive, m_bDelay, m_bRepeat) is arranged into a list of command control words. Each command control word is 4 WORDs, 64 bits, or 8 bytes. The format is as follows:

[0155] "IO|Drive|Delay|Repeat"

[0156] The "IO" field occupies 16 bits of a WORD

[0157] The "Drive" field occupies 16 bits of a WORD

[0158] The "Delay" field occupies 16 bits of a WORD

[0159] The "Repeat" field occupies 16 bits of a WORD

[0160] If the interpolation is performed on the host computer, the above command control word list can be sent to the CNC system's lower computer for processing. Because the data volume after interpolation is large, a batch data transmission method can be used to send data to the lower computer's memory. If the interpolation is performed on the lower computer, the interpolation data is directly transmitted to the memory. The next step is to use the lower computer's function to cache the interpolation data and execute the motion commands and IO commands of each physical axis in the data in sequence.

[0161] For some motion commands and IO commands that need to be generated in real time, such as the height following function of the cutting head in water jet cutting, the lower computer needs to generate compensation motion step commands for the motion axis based on the height information fed back by the height following sensor, and insert the compensation motion step commands in real time during the execution of the original interpolation data.

[0162] "IO" is used to control IO ports and to set special events. Bit 0~bit 7 control the switch of 8 IO ports. Bit 8~bit 11 are used to set a multiple (1, 2, 4, 8, 16 times) by which the delay of Delay is divided to obtain the delay amount during fast forward or fast backward. Bit 12~bit 15 are used to set 16 special events:

[0163] 0001: Program starts

[0164] 0000: Program ends

[0165] 0011: Traversing starts

[0166] 0010: Traversing ends

[0167] 0101: Cutting starts

[0168] 0100: Cutting ends

[0169] 1011: Head-up traversing starts

[0170] 1010: Head-up traversing ends

[0171] "Drive" is used to control the movement of 8 axes. Bit 0~bit 7 control the pulse of 8 axes (1 means one pulse, 0 means no pulse), and bit 8~bit 15 control the direction of each axis (1 means positive direction, 0 means negative direction). The command control word format is as follows: Ex represents the direction of the spare axis, ra|ry|rx represents the direction of three rotating axes, z2|z1 represents the direction of double Z axes, y|x represents the direction of Y and X axes; EX represents the pulse of the spare axis, RA|RY|RX represents the pulse of three rotating axes, Z2|Z1 represents the pulse of double Z axes, Y|X represents the pulse of Y and X axes.

[0172] Ex|ra|ry|rx|z2|z1|y|x|EX|RA|RY|RX|Z2|Z1|Y|X

[0173] "Delay" represents the movement delay amount. The number of periods of the crystal oscillator of the lower computer is used to represent the delay (e.g. 45955 represents a delay of 45955 periods of the crystal oscillator). The speed of the motor can be controlled by this delay amount. The highest bit of Delay is used as a flag bit as a reference clock selection bit:

[0174] Definition of Delay

[15] ,

[0175] 1: 2Mhz;

[0176] 0: 7.8125Khz.

[0177] The rest of the 15 bits are used as follows: when the frequency is 2MHz, the values of 100-32767 in the 15 bits are used to represent the delay amount between 0.00005-0.016 seconds (motor step length 0.0125mm, corresponding speed 15000-47mm / min) (values less than 100 are not used to avoid speed jumps). When the frequency is 7.8125kHz, the values of 125-32767 in the 15 bits are used to represent the delay amount between 0.016-2.55 seconds (corresponding speed 47-0.18mm / min). This can completely cover the speed range of 0.295-19200mm / min. Since an instruction is executed every 200 clock cycles at low speed (7.8125Khz), the delay amount will automatically increase by 0.0001 seconds (an extra 199 clock cycles), which is less than 0.8% for the delay amount between 0.0125-2.55 seconds, and has little effect on the speed. When data is sent to the lower computer, Delay needs to be converted to speed. The calculation method is: 0.0125mm / time represents the speed, time = 1 / Hz*delay amount, speed = (0.0125*2*10^6) / delay. Speed data can also be generated directly when outputting interpolation data, which is used to replace delay data.

[0178] "Repeat" is used to represent the same command line (in order to compress the data amount). If the content of the command line is repeated n times; the value of n is stored in the 16 bits of Repeat, and the maximum value of n is 65535 (the execution number is n, n = 1 indicates that it is executed once, and the maximum execution number is 65535 times).

[0179] As an optional embodiment, if the interpolation module and the control execution module do not share memory, the interpolated step list data is transmitted to the control execution module through data communication or text file data interaction.

[0180] Based on the same concept, the application also provides a machine tool, comprising:

[0181] a machining path generation module, configured to generate machining path model information based on the workpiece ruled surface machining face information, the machining path information comprising tool position point trajectory curve model information, tool axis point trajectory curve model information, and information of a tool position point and tool axis point association function; wherein the tool position point trajectory curve is associated with a curve on the ruled surface machining face, and the tool axis point trajectory curve is associated with a curve below the ruled surface machining face.

[0182] a geometry interpolation module, configured to perform geometry interpolation, decompose each segment of the machining path into interpolation steps, and arrange data of all the interpolation steps into a list according to a machining sequence;

[0183] a speed setting module, configured to perform machining speed setting, and set the machining speed based on the interpolation tool position points after the geometry interpolation;

[0184] an inverse solution calculation module, configured to calculate position information of each physical axis from a tool axis vector of the interpolation tool position points and store the position information;

[0185] an execution module, configured to arrange the interpolation information into a control command list, and sequentially execute data of the control command list.

[0186] Based on the same concept, the application further provides an electronic device, comprising:

[0187] a memory, configured to store a processing program;

[0188] a processor, configured to implement the multi-model based ruled surface machining path interpolation method of any one of the above embodiments when executing the processing program.

[0189] Based on the same concept, the application further provides a readable storage medium, wherein the readable storage medium stores a processing program, and the processing program is executed by a processor to implement the multi-model based ruled surface machining path interpolation method of any one of the above embodiments.

[0190] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific execution of the system and the device described above can refer to the corresponding process in the foregoing method embodiments.

[0191] The embodiments of the application are described in detail above in combination with the drawings, but the application is not limited to the above embodiments. Even if various changes are made to the application, as long as the changes belong to the scope of the claims of the application and equivalent technologies, they still fall within the protection scope of the application.< / pathstep> < / entity> < / entity>

Claims

1. A method of interpolating a machining path for a ruled surface machining face based on a multi-model, characterized by, The method comprises the following steps: generating machining path model information based on the information of the ruled surface of the workpiece, the machining path model information comprising tool position point trajectory curve model information, tool axis point trajectory curve model information, and information of a tool position point and tool axis point correlation function; wherein the tool position point trajectory curve is associated with the upper curve of the ruled surface, the tool axis point trajectory curve is associated with the lower curve of the ruled surface, and the determination of the tool position point and tool axis point correlation function comprises: constructing a mathematical relationship between the arc length position of the tool position point on the trajectory curve and the arc length position of the tool axis point on the trajectory curve; or expressing the discrete corresponding relationship between the arc length position of the tool position point on the trajectory curve and the arc length position of the tool axis point on the trajectory curve in the form of a list; performing geometric interpolation based on the machining path model information, and densifying and decomposing each machining line segment on the machining path into interpolation steps, the interpolation step data comprising tool position point position information and tool axis vector information, and the data of all interpolation steps being arranged into a list in the machining order; setting a machining speed based on the machining path model information, and setting the machining speed based on the interpolation tool position point after geometric interpolation; calculating and storing the position information of each physical axis from the position information and tool axis vector information of the interpolation tool position point; arranging the interpolation information into a control command list, and sequentially executing the control command list data, the interpolation information comprising the position information of each physical axis and the machining speed information.

2. The multi-model based ruled surface machining path interpolation method according to claim 1, characterized by, The generation of the machining path model information based on the information of the ruled surface of the workpiece further comprises the determination of the tool axis point trajectory curve: if the upper curve and the lower curve of the ruled surface are simple geometric curves of straight lines or circular arcs, offsetting the upper curve and the lower curve outward perpendicularly to the machining surface by a tool radius; wherein the offsetting of the circular arc curve is increasing or decreasing the radius by a tool radius; taking the offset upper curve as the tool position point trajectory curve, and taking the offset lower curve as the tool axis point trajectory curve; if the upper curve and the lower curve of the ruled surface are not simple geometric curves, first discretizing each ruled surface into a combination of straight generatrixes, offsetting the upper points and the lower points of each straight generatrix outward perpendicularly to the machining surface by a tool radius, fitting the upper points of the offset straight generatrix group as the upper curve as the tool position point trajectory curve, and fitting the lower points of the straight generatrix group as the lower curve as the tool axis point trajectory curve; after the offsetting, the upper curve and the lower curve of adjacent machining line segments need to be transitioned.

3. The multi-model based ruled surface machining path interpolation method according to claim 1, wherein, constructing the mathematical relationship of the arc length of the tool position point trajectory curve and the tool axis point trajectory curve by equally dividing the tool position point trajectory curve and the tool axis point trajectory curve.

4. The multi-model based ruled surface machining path interpolation method according to claim 3, wherein, The method further comprises: at a corner, the tool position point trajectory degenerates into a point, in the list, the tool position point trajectory at the corner corresponds to a segment of the tool axis point trajectory curve arc length, and an arc angle step length is adopted during interpolation.

5. The multi-model based ruled surface machining path interpolation method according to claim 1, wherein, The generation of the machining path model information based on the information of the ruled surface of the workpiece further comprises: The CAM module expresses the line segment of the generated machining path in a line segment class or structure of an object-oriented programming language, and the entire machining path can be expressed by a list of objects of the line segment class or structure, the machining line, the cutting-in and cutting-out line, and the fast-forward line can be distinguished by a member variable of the line segment class or structure representing a line segment type, the theoretical machining speed can be expressed by a member variable of the line segment class or structure representing a machining speed, the tool position point trajectory curve function can be expressed by one or more member functions of the line segment class or structure representing a mathematical model of a geometric curve, the tool axis point trajectory curve function can be expressed by one or more member functions of the line segment class or structure representing a mathematical model of a geometric curve, and the correlation function can be expressed by one or more member functions of the line segment class or structure representing a mathematical model of a correlation function; the interpolation module obtains the machining path model information by sharing the memory with the CAM module; Alternatively, the machining path model information is transmitted from the CAM module to the interpolation module by passing the modeling parameters, the modeling parameters include the general parameters of the path line segment, the model parameters of the tool position point trajectory curve, and the model parameters of the tool axis point trajectory curve, and the machining path model information expressed by the modeling parameters can be transmitted through a text file or other data interaction mode, and the machining path model information to be included includes the tool position point and tool axis point information at the origin of the machining path.

6. The multi-model based ruled surface machining path interpolation method according to claim 1, wherein, The machining speed setting based on the machining path model information further includes: The process model is called based on the machining path model information to calculate the theoretical machining speed of each machining path line segment and the end point of the path line segment; The process model includes a function relationship taking the curvature change of the path line segment curve as the independent variable and the machining speed as the dependent variable, and the greater the curvature change of the path line segment curve, the slower the speed, and the greater the change in the path direction of the adjacent two line segments, the slower the speed when calculating the speed of the end point of the path line segment.

7. The multi-model based ruled surface machining path interpolation method according to claim 1, wherein, The method further includes: A zero-length line segment is added at each line segment connection point, and the theoretical machining speed of the zero-length line segment reflects the change in the tangential direction of the adjacent line segments, and the greater the change in the tangential direction, the smaller the theoretical machining speed of the connection point, and the connection point can also realize the transition of the tool axis vector direction of the adjacent line segments; And / or, a transition arc is inserted at the connection point where the tangential direction of the machining path changes by more than a threshold value.

8. The multi-model based ruled surface machining path interpolation method of claim 1, wherein, The method further includes: Geometric interpolation: determine the interpolation step, the interpolation step is calculated according to an interpolation period and a theoretical machining speed; or, determine the interpolation step according to the control accuracy, and then calculate the number of interpolation periods required for the interpolation step according to the interpolation period and the theoretical machining speed; wherein for the zero-length line segment, the interpolation step represents an arc angle of the tool axis direction change within an interpolation period or an arc angle determined according to the arc angle control accuracy; The interpolation tool position point is obtained by dividing the tool position point trajectory curve of the machining path with the interpolation step, and for the zero-length line segment, the arc angle of the tool axis direction change is divided; The interpolation point on the tool axis point trajectory curve is found through the tool position point and the tool axis point correlation function, and the tool axis point coordinate and tool axis vector information corresponding to the interpolation tool position point are obtained; The interpolation point data is expressed by a step class or structure of an object-oriented programming language, and the entire interpolated machining path is expressed by an object list of the step class or structure; The object list of the step class or structure is subjected to speed interpolation: according to the acceleration limit of the machine, the acceleration limit of the specific process, and the acceleration-deceleration model, the theoretical machining speed on the path line segment of the tool position point is taken as the maximum value, the theoretical machining speed at the end point of the path line segment is taken as the starting point, and the machining speed is adjusted step by step in both directions of the midpoint of the path line segment, so that the theoretical machining speed corresponding to each interpolation tool position point is adjusted, and the adjusted machining speed is taken as a member variable of the step class or structure and stored in the object list of the step class or structure.

9. The multi-model based ruled surface machining path interpolation method according to claim 8, wherein, For the case of interpolation in the CAM or the case of sharing memory between the interpolation module and the CAM module, the associated function can be obtained from one or more member functions of the line segment class or structure that express the mathematical model of the associated function; for the zero-length tool position line segment, the associated function is not needed, the tool axis point is determined by the arc angle interpolation step, and is irrelevant to the tool position; for the case where the tool axis point trajectory curve degenerates into a point, the associated function is not needed to determine the tool axis point.

10. The multi-model based ruled surface machining path interpolation method of claim 8, wherein, The method further comprises: if the machining path model information is transmitted from the CAM module to the interpolation module in the form of modeling parameters, the modeling parameters are restored to the mathematical model in the interpolation module.

11. The multi-model based ruled surface machining path interpolation method of claim 8, wherein, The method further comprises: if the interpolation module and the control execution module do not share memory, the interpolated step list data is transmitted to the control execution module through data communication or text file data interaction.

12. The multi-model based ruled surface machining path interpolation method of claim 1, wherein, When generating the machining path model information based on the straight-line machining surface information of the workpiece, an offset amount that needs to be reversely compensated is calculated based on a prediction mathematical model and preset process parameters, the prediction mathematical model includes but is not limited to one or more of a cutting speed model, a slotting taper model, a trailing amount model and a machine tool random error model established based on a machining mechanism, and the error caused in the machining process is effectively compensated by optimizing the offset initial tool axis vector according to the offset amount that needs to be reversely compensated: A first prediction mathematical model is called, the trailing amount generated by cutting the workpiece is calculated according to the target parameter information of the current position point, and then a first angle that needs to be swung along the cutting feed direction is calculated to perform reverse compensation; A first component of the initial tool axis vector along the cutting feed direction is obtained, and a first optimization is performed according to the first angle to obtain a second component result of the optimized tool axis vector along the cutting feed direction; A second prediction mathematical model is called, the lateral taper generated by cutting the workpiece is calculated according to the target parameter information of the current position point, and then a second angle that needs to be swung along the perpendicular direction of the cutting feed direction is calculated to perform reverse compensation; A third component of the initial tool axis vector along the perpendicular direction of the cutting feed direction is obtained, and a second optimization is performed according to the second angle to obtain a fourth component result of the optimized tool axis vector perpendicular to the cutting feed direction. The final optimized tool axis vector is synthesized according to the values of the second component and the fourth component.

13. A machine tool, characterized by The method comprises: The machining path generation module is configured to generate machining path model information based on the workpiece ruled surface information, the machining path model information including tool position point trajectory curve model information, tool axis point trajectory curve model information, and information of a tool position point and tool axis point correlation function; wherein the tool position point trajectory curve is associated with an along curve on the ruled surface, the tool axis point trajectory curve is associated with an under curve on the ruled surface, and the determination of the tool position point and tool axis point correlation function includes: constructing a mathematical relationship between an arc length position of the tool position point on the trajectory curve and an arc length position of the tool axis point on the trajectory curve; or expressing a discrete corresponding relationship between the arc length position of the tool position point on the trajectory curve and the arc length position of the tool axis point on the trajectory curve in the form of a list; The geometry interpolation module is configured to perform geometry interpolation, to divide each piece of machining path on the machining path into interpolation steps, and to arrange data of all interpolation steps into a list according to a machining sequence; The speed setting module is configured to perform machining speed setting, to set machining speed based on the interpolation tool position point after geometry interpolation; The inverse solution calculation module is configured to calculate position information of each physical axis from a tool axis vector of the interpolation tool position point and to store the position information; The execution module is configured to arrange the interpolation information into a control command list and to sequentially execute data of the control command list.

14. An electronic device, comprising: The memory is configured to store a processing program; The processor is configured to implement the multi-model based ruled surface machining path interpolation method according to any one of claims 1 to 12 when executing the processing program. The readable storage medium stores a processing program, and the processing program is configured to implement the multi-model based ruled surface machining path interpolation method according to any one of claims 1 to 12 when executed by a processor.

15. A readable storage medium, characterized by, ​

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