Tool path and speed planning method and device for five-axis parallel kinematics machining robot

Abstract

The application discloses a tool path and speed planning method and device of a five-axis parallel machining robot, wherein the method comprises the following steps: obtaining a mapping relationship between a tool pose and lengths of each driving branch chain based on an inverse kinematics model of the five-axis parallel machining robot; reading a tool tip point position vector and a tool axis vector in a tool position file; preprocessing an original point sequence of the tool position file, fitting a B-spline curve in combination with a symmetrical arrangement strategy and a continuity condition, unitizing the curve to generate a tool axis vector path; if a fitting error of the tool tip point position and the tool axis vector does not meet an error requirement, iteration is continued and linear fitting is re-performed; a feed speed curve is planned based on a preset constraint condition, and is discretized according to a preset interpolation period, so that a servo control system can perform numerical control machining according to information of interpolation points. Thus, the problems of high complexity of tool path calculation, low efficiency of speed planning and the like in the related art are solved.

Description

Technical Field

[0001] The present application relates to the field of robotics and application technology, and in particular to a tool path and speed planning method and device for a five-axis parallel machining robot. Background Art

[0002] In related technologies, path planning can use Newton-Raphson iterative optimization technology to ensure the high-order continuity of the tool path, or use quadratic programming to perform two B-spline curve fittings on the fitting curve and the remaining curve to achieve C 3 Continuity. For speed planning, you can improve planning accuracy by adding set constraints during processing or increase the given feed rate during processing to reduce the overall processing time. Traditional tool path planning and feed rate planning are processed by treating all tool locations as a whole.

[0003] However, the use of Newton-Raphson iterative optimization technology or quadratic fitting technology in related technologies leads to a high complexity in tool path calculation, which cannot simultaneously take into account both the high-order continuity of the tool path and the simplicity of calculation, and cannot simultaneously take into account both planning accuracy and planning speed, which urgently needs to be solved. Summary of the Invention

[0004] This application is based on the following problems and understandings made by the inventors:

[0005] With the continuous development of the aerospace field, the design of key components has become more mature, and their shapes and structures have become more and more complex. For example, turbine blades, impellers, and aircraft structural parts often have complex geometric shapes, high metal material removal rates, high precision requirements, and high-quality surface processing requirements. In order to complete the processing of these parts, the processing equipment is required to have the ability to perform one-time clamping processing, compound angle processing, and fast and precise processing. Conventional processing equipment is mostly developed based on serial mechanisms, which have the advantages of large working space, fast moving speed, and easy solution of positive kinematic equations. However, serial machine tools will face the problem of automatic rotation of tools in the singular domain during actual processing.

[0006] In order to fundamentally solve the problem of automatic rotation of the tool in the singularity domain and further improve the processing quality and efficiency, the relevant technology proposes a five-axis full parallel processing robot structure based on the basic mechanism configuration of 4-SPU&SPR according to the processing advantages of the parallel structure. From the perspective of the mechanism, the robot realizes flexible posture adjustment of the end through multi-axis coupled motion. There is no singularity in the posture workspace. Theoretically, it can smoothly pass through the opening and closing angle conversion area without reducing the speed. However, due to the mismatch between the control algorithm in the commercial CNC system and the robot performance, the high flexibility of the coupled posture adjustment motion cannot be brought into play.

[0007] Since the tool axis vector is a variable whose norm is always 1, the influence of curve unitization on continuity is a key issue. In existing studies, some methods are used to achieve C by fitting a B-spline curve on the plane formed by the endpoints of the three tool axis vectors. 2 Continuity, converting three-dimensional curve fitting into two-dimensional curve fitting; some directly fit the tool axis vector derived through the same curve fitting operation as the tool tip position vector to the curve and normalize it, but in the process of normalizing the fitting curve, an approximate solution method is often used, which cannot strictly guarantee the high-order continuity of the final curve.

[0008] In addition to the continuity of the curve, achieving real-time performance is also an important factor, which depends largely on the complexity of the calculation. Some studies use Newton-Raphson iterative optimization technology to ensure the high-order continuity of the tool path, and some use quadratic programming to perform two B-spline curve fittings at the transition point and the remaining curve to achieve C 3 Continuity, these research methods cannot take into account both the high-order continuity of the tool path and the simplicity of calculation.

[0009] For speed planning, traditional planning methods provide a variety of constraints and planning algorithms. Adding set constraints during processing will improve processing accuracy, while increasing the computational burden and affecting processing speed. Increasing the given feed rate during processing will reduce the overall processing time and affect processing accuracy, making it difficult to achieve a balance between processing speed and processing accuracy in the actual processing planning process. In addition, traditional tool path smoothing and feed rate planning often process all tool position points as a whole, which reduces processing efficiency and requires a large storage space, and urgently needs to be improved.

[0010] The present application provides a tool path and speed planning method and device for a five-axis parallel machining robot to solve the problem that the Newton-Raphson iterative optimization technology or quadratic fitting technology used in related technologies leads to high complexity in tool path calculation, and it is impossible to simultaneously take into account both the high-order continuity of the tool path and the simplicity of calculation, and it is also impossible to simultaneously take into account both planning accuracy and planning speed.

[0011] The first embodiment of the present application provides a tool path and speed planning method for a five-axis parallel machining robot, comprising the following steps: based on the inverse kinematics model of the five-axis parallel machining robot, obtaining the mapping relationship between the tool posture and the length of each drive branch chain; reading a series of discrete tool tip point position vectors and tool axis vectors contained in the tool position file to obtain an original point sequence that needs to be fitted; preprocessing the original point sequence that needs to be fitted to generate an alternative starting point and end point of the processed original point sequence, and wrapping the original starting point and end point in the processed original point sequence; based on the processed original point sequence, using target parameters to describe the tool tip point position and tool axis vector, and combining the symmetric arrangement strategy and continuity conditions The method comprises the following steps: fitting a B-spline curve, directly connecting the fitted curves to obtain a third-order continuous tool tip point position path, normalizing the tool axis vector curve, and generating a third-order continuous tool axis vector path; calculating the fitting error between the tool tip point position path and the tool axis vector path, and judging whether the fitting error meets the error requirement; if it does not meet the error requirement, re-performing linear fitting until it meets the error requirement, so that the fitting error falls into the specified error range; planning the feed speed based on the preset linear constraint condition to obtain the feed speed curve, and discretizing the feed speed curve according to the preset interpolation period, so that the servo control system performs CNC machining according to the information of the interpolation point.

[0012] Optionally, in one embodiment of the present application, the original point sequence to be fitted is preprocessed to generate alternative starting points and end points of the processed original point sequence, and the original starting point and end point are wrapped in the processed original point sequence, including: setting the new starting point as the symmetrical point of the original second point with respect to the original first point; setting the new penultimate point as the symmetrical point of the original penultimate point with respect to the original penultimate point; after preprocessing, the original starting point and end point will be wrapped in the sequence, so that the tool processing position of each point is within the error range of the theoretical processing position.

[0013] Optionally, in one embodiment of the present application, based on the processed original point sequence, the tool axis direction is described with target parameters, and a B-spline curve is fitted in combination with a symmetrical layout strategy and continuity conditions, and the fitted curves are directly connected to obtain a third-order continuous tool tip point position path. At the same time, the tool axis vector curve is unitized to generate a third-order continuous tool axis vector path, including: combining the third-order continuity constraint conditions and symmetrical layout strategy of the tool path span, calculating the relative positions of the control points required for the preliminary fitting of the local curve based on every three tool position points; based on the relative positions of the control points, a quintic fitting B-spline curve is designed with the middle tool position point as the central control point to obtain a third-order continuous tool tip point position path, and the tool axis vector curve is unitized; based on the symmetrical changes of the unitized tool axis vector curve, the third-order continuous tool axis vector path is obtained.

[0014] Optionally, in one embodiment of the present application, the feed speed planning based on the preset linear constraints obtains a feed speed curve, and the feed speed curve is discretized according to a preset interpolation period, so that the servo control system performs CNC machining according to the data information of the interpolation point, including: based on the preset linear constraints, judging the speed extremes of each point on the machining path, and determining the speed correlation between each interpolation point by reading the speed data of the first two points, wherein the preset linear constraints include geometric error, normal acceleration jerk limit, tangential speed limit and tangential acceleration jerk limit; based on the preset linear constraints, taking B-spline curve as unit, reading the tool path data after path planning, integrating the time dimension into each path segment in sequence and interpolating, to obtain the machining information required by the servo control system.

[0015] Optionally, in one embodiment of the present application, the parameters of the interpolation point are composed of an initial value and a compensation value, and the expression thereof is as follows:

[0016] u k+1 =u temp,k+1 +Δu k+1 ,

[0017] Among them, u k+1 Indicates the parameters of the interpolation point, u temp,k+1 Indicates the initial value of the new interpolation point curve parameter, Δu k+1 Indicates the parameter compensation amount.

[0018] The second embodiment of the present application provides a tool path and speed planning device for a five-axis parallel machining robot, including: a first acquisition module, for obtaining the mapping relationship between the tool posture and the length of each drive branch chain based on the inverse kinematics model of the five-axis parallel machining robot; a reading module, for reading a series of discrete tool tip point position vectors and tool axis vectors contained in the tool position file, and obtaining an original point sequence that needs to be fitted; a generation module, for preprocessing the original point sequence that needs to be fitted, generating an alternative starting point and end point of the processed original point sequence, and wrapping the original starting point and end point in the processed original point sequence; a second acquisition module, for describing the tool tip point position and tool axis vector with target parameters based on the processed original point sequence, and combining the symmetrical arrangement strategy and the connection strategy. The B-spline curve is fitted according to continuity conditions, and the fitted curves are directly connected to obtain a third-order continuous tool tip point position path, while the tool axis vector curve is normalized to generate a third-order continuous tool axis vector path; a calculation module is used to calculate the fitting error of the tool tip point position path and the tool axis vector path, and to determine whether the fitting error meets the error requirement; a processing module is used to re-perform linear fitting if the error requirement is not met, until the error requirement is met, so that the fitting error falls into the specified error range; a planning module is used to plan the feed speed based on the preset linear constraint condition, obtain the feed speed curve, and discretize the feed speed curve according to the preset interpolation period, so that the servo control system can perform CNC machining according to the information of the interpolation point.

[0019] Optionally, in one embodiment of the present application, the generation module includes: a first setting unit, used to set the new starting point as the symmetrical point of the original second point with respect to the original first point; a second setting unit, used to set the new penultimate point as the symmetrical point of the original penultimate point with respect to the original penultimate point; a processing unit, used to wrap the original starting point and end point in the sequence after preprocessing, so that the tool processing position of each point is within the error range of the theoretical processing position.

[0020] Optionally, in one embodiment of the present application, the second acquisition module includes: a calculation unit, which is used to combine the third-order continuity constraint conditions and symmetrical layout strategy of the tool path span, and calculate the relative positions of the control points required for the preliminary fitting of the local curve based on every three tool position points; a first acquisition unit, which is used to design a quintic fitting B-spline curve with the middle tool position point as the central control point based on the relative positions of the control points, and obtain the third-order continuous tool tip point position path while normalizing the tool axis vector curve; a first determination unit, which is used to obtain the third-order continuous tool axis vector path based on the symmetrical changes of the normalized tool axis vector curve.

[0021] Optionally, in one embodiment of the present application, the planning module includes: a second determination unit, which is used to judge the speed extreme value of each point on the processing path based on the preset linear constraint conditions, and determine the speed correlation between each interpolation point by reading the speed data of the first two points, wherein the preset linear constraint conditions include geometric error, normal acceleration jerk limit, tangential speed limit and tangential acceleration jerk limit; a second acquisition unit, which is used to read the tool path data after path planning based on the preset linear constraint conditions and in units of B-spline curves, integrate the time dimension into each path segment in sequence and perform interpolation to obtain the processing information required by the servo control system.

[0022] Optionally, in one embodiment of the present application, the parameters of the interpolation point are composed of an initial value and a compensation value, and the expression thereof is as follows:

[0023] u k+1 =u temp,k+1 +Δu k+1 ,

[0024] Among them, u k+1 Indicates the parameters of the interpolation point, u temp,k+1 Indicates the initial value of the new interpolation point curve parameter, Δu k+1 Indicates parameter compensation amount.

[0025] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein the processor executes the program to implement the tool path and speed planning method of the five-axis parallel machining robot as described in the above embodiment.

[0026] The fourth aspect of the present application provides a computer-readable storage medium, which stores a computer program. When the program is executed by a processor, it implements the tool path and speed planning method of the five-axis parallel machining robot as described above.

[0027] The embodiment of the application can obtain the mapping relationship between the tool posture and the length of each driving branch chain based on the inverse kinematics model of the five-axis parallel machining robot, read the tool tip point position vector and the tool axis vector in the tool position file, preprocess the original point sequence of the tool position file, fit the B-spline curve combined with the symmetrical arrangement strategy and the continuity condition to obtain the tool tip point position path, unitize the tool axis vector curve to generate the tool axis vector path, and calculate the fitting error of the tool tip point position path and the tool axis vector path. If the error does not meet the requirement, linear fitting is continued and re-performed, then the feed speed is planned based on the preset constraint condition, and is discretized according to the preset interpolation period, so that the servo control system can perform numerical control machining according to the information of the interpolation point, thereby effectively improving the calculation simplicity of the path planning and the processing efficiency of the speed planning. Thus, the problems that the tool path calculation is high in complexity, the high-order continuity of the tool path and the calculation simplicity cannot be simultaneously considered, and the planning accuracy and the planning speed cannot be simultaneously considered are solved by using the Newton-Raphson iterative optimization technology or the quadratic fitting technology in the related art.

[0028] Additional aspects and advantages of the application will be made apparent by the following description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS

[0029] The above and / or additional aspects and advantages of the application will become apparent and be made clear to those skilled in the art from the following description and the appended claims, taken in conjunction with the accompanying drawings.

[0030] Figure 1 A flowchart of a tool path and speed planning method of a five-axis parallel machining robot according to an embodiment of the application is shown in FIG. 1;

[0031] Figure 2 A model diagram of a five-axis parallel machining robot according to one embodiment of the application is shown in FIG. 2;

[0032] Figure 3 A tool path preprocessing diagram according to one embodiment of the application is shown in FIG. 3;

[0033] Figure 4 A tool axis vector conversion smoothing diagram according to one embodiment of the application is shown in FIG. 4;

[0034] Figure 5 A tool tip point position conversion smoothing diagram according to one embodiment of the application is shown in FIG. 5;

[0035] Figure 6 A principle diagram of iterative optimization according to one embodiment of the application is shown in FIG. 6;

[0036] Figure 7A schematic diagram of the principle of feed rate planning and interpolation algorithm according to a specific embodiment of the present application;

[0037] Figure 8 Schematic diagram of the structure of a tool path and speed planning device for a five-axis parallel machining robot provided in an embodiment of the present application;

[0038] Figure 9 A schematic diagram of the structure of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0039] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0040] The following describes the tool path and speed planning method and device of the five-axis parallel machining robot in the embodiment of the present application with reference to the accompanying drawings. In view of the high complexity of the tool path calculation caused by the use of Newton-Raphson iterative optimization technology or quadratic fitting technology in the related technologies mentioned in the background technology center, and the inability to simultaneously take into account the high-order continuity of the tool path and the simplicity of calculation, and the problem that the planning accuracy and planning speed cannot be taken into account at the same time, the present application provides a tool path and speed planning method for a five-axis parallel machining robot. In this method, based on the inverse kinematics model of the five-axis parallel machining robot, the mapping relationship between the tool posture and the length of each drive branch chain can be obtained, and the tool tip point position vector and tool axis vector in the tool position file can be read. The original point sequence of the tool location file is preprocessed, and the B-spline curve is fitted in combination with the symmetric layout strategy and continuity conditions to obtain the tool tip point position path. The tool axis vector curve is normalized to generate the tool axis vector path, and the fitting error of the tool tip point position path and the tool axis vector path is calculated. If the error requirements are not met, the iteration is continued and the linear fitting is re-performed. Then, the feed speed is planned based on the preset constraints and discretized according to the preset interpolation cycle, so that the servo control system can perform CNC machining based on the data information of the interpolation point, thereby effectively improving the calculation simplicity of the path planning and the processing efficiency of the speed planning. Thus, the problem of using Newton-Raphson iterative optimization technology or quadratic fitting technology in related technologies, which leads to high complexity of tool path calculation, inability to simultaneously take into account the high-order continuity and calculation simplicity of the tool path, and inability to simultaneously take into account the planning accuracy and planning speed, is solved.

[0041] Specifically, Figure 1A flow chart of a tool path and speed planning method for a five-axis parallel machining robot provided in an embodiment of the present application.

[0042] like Figure 1 As shown, the tool path and speed planning method of the five-axis parallel machining robot includes the following steps:

[0043] In step S101, based on the inverse kinematics model of the five-axis parallel machining robot, a mapping relationship between the tool posture and the length of each drive branch chain is obtained.

[0044] It is understandable that the embodiment of the present application can be based on the inverse kinematics model of the five-axis parallel machining robot, for example, Figure 2 As shown in the figure, it is a five-axis parallel machining robot model, which can be connected between the fixed platform and the main spindle by five branches. By changing the length of the five branches, the main spindle is driven to achieve three translational degrees of freedom and two rotational degrees of freedom, and five-axis linkage motion can be realized, thereby obtaining the mapping relationship between the tool posture and the length of each drive branch, thereby effectively improving the executability of the tool path and speed planning.

[0045] In step S102, a series of discrete tool tip point position vectors and tool axis vectors contained in the tool location file are read to obtain an original point sequence that needs to be fitted.

[0046] It is understandable that the embodiment of the present application can read a series of discrete tool tip position vectors and tool axis vectors contained in the tool location file, for example, the tool tip position vectors {p1, p2, ..., p N-1 ,p N} and tool axis vector {o1,o2,...,o N-1 ,o N}, and obtain the original point sequence that needs to be fitted, thereby effectively reducing the overall processing time.

[0047] In step S103 , the original point sequence to be fitted is pre-processed to generate a replacement start point and end point of the processed original point sequence, and the original start point and end point are wrapped in the processed original point sequence.

[0048] It is understandable that the embodiment of the present application can pre-process the original point sequence that needs to be fitted in the following steps, generate alternative starting points and end points of the processed original point sequence, and wrap the original starting points and end points in the processed original point sequence, thereby effectively improving the processing accuracy.

[0049] In one embodiment of the present application, the original point sequence to be fitted is preprocessed to generate alternative starting points and end points of the processed original point sequence, and the original starting point and end point are wrapped in the processed original point sequence, including: setting the new starting point as the symmetrical point of the original second point with respect to the original first point; setting the new penultimate point as the symmetrical point of the original penultimate point with respect to the original penultimate point; after preprocessing, the original starting point and end point are wrapped in the processed original point sequence, so that the tool processing position of each point is within the error range of the theoretical processing position.

[0050] During the actual execution process, the embodiment of the present application can set the new starting point as the symmetrical point of the original second point with respect to the original first point, and set the new penultimate point as the symmetrical point of the original penultimate point with respect to the original penultimate point. After tool path preprocessing, the original starting point and end point are wrapped in the processed original point sequence, thereby ensuring that the tool processing position of each point is within the error range of the theoretical processing position, effectively improving the processing accuracy.

[0051] For example, if Figure 3 As shown, since the fitting process in the embodiment of the present application reads three tool tip positions or tool axis vectors each time and performs curve fitting at the intermediate point, resulting in no curve fitting at the starting point and end point, the tool tip position and tool axis vector can be preprocessed to generate alternative new starting point and end point. Figure 3 Set the new starting point to the symmetrical point between the original second point and the original first point, and the new end point to the symmetrical point between the original second to last point and the original end point.

[0052] In step S104, based on the processed original point sequence, the target parameters are used to describe the tool tip point position and tool axis direction, and the B-spline curve is fitted in combination with the symmetric layout strategy and continuity condition. The fitted curves are directly connected to obtain a third-order continuous tool tip point position path. At the same time, the tool axis vector curve is normalized to generate a third-order continuous tool axis vector path.

[0053] It is understandable that the embodiment of the present application can use target parameters to describe the tool tip position and tool axis direction based on the sequence of the following steps, such as using parameter O x ,O y ,O z The tool axis direction is described, and the B-spline curve is fitted in combination with the symmetrical layout strategy and continuity conditions. The fitted curves are directly connected to obtain a third-order continuous tool tip point position path. At the same time, the tool axis vector curve is normalized to generate a third-order continuous tool axis vector path.

[0054] Among them, in one embodiment of the present application, based on the processed original point sequence, the target parameters are used to describe the tool tip point position and the tool axis direction, and the B-spline curve is fitted in combination with the symmetrical layout strategy and continuity conditions, and the fitted curves are directly connected to obtain a third-order continuous tool tip point position path. At the same time, the tool axis vector curve is unitized to generate a third-order continuous tool axis vector path, including: combining the third-order continuity constraint conditions and the symmetrical layout strategy of the tool path span, calculating the relative positions of the control points required for the preliminary fitting of the local curve based on every three tool position points; based on the relative positions of the control points, a quintic fitting B-spline curve is designed with the middle tool position point as the central control point to obtain a third-order continuous tool tip point position path, and the tool axis vector curve is unitized; based on the symmetrical changes of the unitized tool axis vector curve, a third-order continuous tool axis vector path is obtained.

[0055] As a possible implementation method, in the process of tool axis vector path fitting, the embodiment of the present application can read three consecutive tool axis vectors O on the original tool path. i-1 , O i , O i+1 Considering the influence of the normalization process on the slope of the curve, the fitted B-spline curve is not directly connected to the arc, but the two B-spline curves before and after are directly connected, that is, at O i Insert the quintic B-spline fitting curve at the position to complete the highly continuous connection between the front and rear tool movement paths. The B-spline curve has a basis function N i,n (u), control point O i (u)=[O ix ,O iy ,O iz ] T , (i=0,...,N) and the degree n of the curve are used to define the tool position. That is, for the tool position, the transition smoothing is achieved by inserting a quintic B-spline curve. The expression of the inserted curve is as follows:

[0056]

[0057] Among them, O i =[O ix ,O iy ,O iz ], (i=0,...,6) represents the control point, N i,n (u) represents the n-th basis function, which can be obtained by iteration according to the spline parameters u∈[0,1] and the node vector U=[u0,...,u m ], m=N+n+1.

[0058] Specifically, the iterative method is:

[0059]

[0060] wherein, as shown in Figure 4 the first half of the control points O 1,i ,O 2,i ,O 3,i ,O 4,i and the second half of the control points O 7,i-1 ,O 6,i-1 ,O 5,i-1 ,O 4,i-1 of the first B-spline fitting curve are all on O i-1 O i the first half of the control points O 7,i ,O 6,i ,O 5,i ,O 4,i and the second half of the control points O 1,i+1 ,O 2,i+1 ,O 3,i+1 ,O 4,i+1 of the second B-spline fitting curve are all on O i O i+1 the middle control point O3 of the fitting B-spline curve is at the intersection of the line segment O i-1 O i and the line segment O i O i+1 To achieve the simple calculation of the fitting B-spline curve as much as possible, the number of control points is reduced as much as possible, and therefore, N = 6 is set.

[0061] According to the determination rule of the basis function itself, the node vector is defined as:

[0062] U = [0 0 0 0 0 0 0.5 1 1 1 1 1 1],

[0063] The relative position relationship of the control points of the designed B-spline curve is as follows:

[0064]

[0065] Finally, according to the read three consecutive tool position point tool axis vector data and the proportion relationship determined by the above method, the position of the control point is determined, and the fitting B-spline curve is calculated.

[0066] According to the theoretical derivation of Sneha Tulsyan et al., since the norm of all direction control vectors O i is uniform, the absolute value of O(u) remains 1 in the entire spline segment, and the curve is unitized, which is shown as follows:

[0067]

[0068] Thus, the final tool axis vector path is obtained, which makes the spline curve path segments highly continuous and can adapt to the working mode of fast reading and processing.

[0069] In addition, after normalization, the first-order derivative at the starting point of the B-spline curve is related to O0, O1, the second-order derivative is related to O0, O1, O2, the third-order derivative is related to O0, O1, O2, O3, the first-order derivative at the end point is related to O6, O5, the second-order derivative is related to O4, O5, O6, and the third-order derivative is related to O6, O5, O4, O3.

[0070] Since the last three control points of the first segment of the B-spline curve and the first three control points of the second segment of the B-spline curve are arranged symmetrically, the control points that affect the boundary slope will also change symmetrically during the unitization process. Therefore, after unitization, the first-order, second-order, and third-order derivatives of the end point of the first segment of the B-spline curve and the first-order, second-order, and third-order derivatives of the end point of the second segment of the B-spline curve will remain consistent, thereby ensuring the G of the tool axis vector fitting curve. 3 Continuity.

[0071] In some embodiments, the embodiments of the present application can perform tool tip point position curve fitting, so that the tool tip point position and the tool axis vector can use the same fitting method to achieve synchronous transition and smoothing of the two.

[0072] For example, the embodiment of the present application can read three knife position points p in sequence. i-1 、p i 、p i+1 Perform curve fitting and connect the two fitted B-spline curves directly. i A quintic B-spline fitting curve is designed to complete the high degree of continuity required between each machining path. The B-spline curve is composed of the basis function N i,n (u), control point P i (u)=[P ix ,P iy ,P iz ] T , (i=0,...,N) and the curve number n are determined together, which is specifically expressed as follows:

[0073]

[0074] After fitting, the B-spline curves of adjacent tool positions are required to be smoothly connected. Therefore, the first-order, second-order, and third-order derivatives at the end of the previous B-spline curve should be equal to the corresponding derivatives at the starting point of the next B-spline curve. The following formula is obtained:

[0075]

[0076] Likewise, Figure 5As shown, the transition curve order can be set to 5th order, to simplify the required calculation, the curve control points are defined as small as possible, the first half control points P 1,i 2,i 3,i 4,i of the preceding B-spline fitting curve 7,i-1 6,i-1 5,i-1 4,i-1 are all on p i-1 p i , the last four control points P 7,i 6,i 5,i 4,i of the designed B-spline fitting curve 1,i+1 2,i+1 3,i+1 4,i+1 are all on p i p i+1 , the center control point P3 of the designed B-spline fitting curve is located on the intersection of the line segment p i-1 p i and the line segment p i p i+1 .

[0077] wherein the node vector is set as:

[0078] U = [0 0 0 0 0 0 0.5 1 1 1 1 1 1],

[0079] the relative position relationship of the control points of the designed B-spline curve is as follows:

[0080]

[0081] Finally, according to the read three consecutive tool position point data (nose point position) and the proportion relationship determined by the above method, the position of the control point can be determined, and the fitting curve of each tool position point is obtained, that is, the final nose point position path, so as to ensure the G 3 continuity of the nose point position fitting curve.

[0082] In step S105, the fitting error of the tool nose point position path and the tool axis vector path is calculated, and it is judged whether the fitting error meets the error requirement.

[0083] It can be understood that the embodiments of the present application can calculate the fitting error of the tool nose point position path and the tool axis vector path according to the spline curve obtained by fitting, and judge whether the fitting error meets the error requirement, so as to effectively improve the controllability of the machining precision.​​​​​​​​​​​​

[0084] It should be noted that the error requirement is set by those skilled in the art according to actual conditions and is not specifically limited here.

[0085] In step S106 , if the error requirement is not met, linear fitting is performed again until the error requirement is met, so that the fitting error falls within the specified error range.

[0086] It can be understood that the embodiment of the present application can re-perform linear fitting when the fitting error does not meet the error requirements until it meets the error requirements, so that the fitting error falls into the specified error range. This iterative optimization processing method helps to achieve error controllability of the tool path smoothing solution.

[0087] For example, the maximum fitting error value ε is located at the midpoint of the B-spline fitting curve. When u = 0.5, the expression of the maximum error value is:

[0088] ε=O3-Ori(0.5),

[0089] Among them, ε represents the maximum fitting error value.

[0090] For example, Figure 6 As shown, in the embodiment of the present application, the fitting errors of the tool tip position path and the tool axis vector path without iteration can be calculated based on the spline curve obtained by preliminary fitting, and whether the error requirements are met is determined. If the fitting errors meet the accuracy requirements, the number of iterations is recorded as 0, and no iteration operation is performed. If the tool axis vector is out of tolerance, let:

[0091]

[0092] And according to the new O i-1 , O i , O i+1 Re-perform curve fitting and observe whether the fitting error meets the error requirements. If not, continue iteration until the fitting error falls within the specified error range, and record the corresponding minimum number of iterations.

[0093] In addition, if the tool tip position is out of tolerance, let:

[0094]

[0095] And according to the new p i-1 ,p i ,p i+1 Re-perform curve fitting and observe whether the fitting error meets the requirements. If not, continue iteration until the fitting error falls within the specified error range and record the corresponding minimum number of iterations.

[0096] Next, compare the minimum number of iterations under which the tool tip position and tool axis vector meet the error requirements, and take the larger value as the actual number of iterations. Finally, the O after iteration can be calculated according to the actual number of iterations. i-1 , O i+1 、p i-1 、p i+1 , and are stored as insertion points in the original point sequence for final fitting, thereby effectively achieving error controllable tool path smoothing scheme.

[0097] In step S107, feed speed planning is performed based on preset linear constraints to obtain a feed speed curve, and the feed speed curve is discretized according to a preset interpolation period, so that the servo control system can perform CNC machining according to the information of the interpolation points.

[0098] It can be understood that the embodiment of the present application can perform feed speed planning based on the constraints in the following steps to obtain a feed speed curve, and discretize the feed speed curve according to the interpolation cycle, that is, complete the accurate calculation of the corresponding interpolation points, so that the servo control system can perform CNC machining based on the information of the interpolation points, thereby effectively improving the machining accuracy.

[0099] In one embodiment of the present application, feed speed planning is performed based on preset linear constraints to obtain a feed speed curve, and the feed speed curve is discretized according to a preset interpolation period, so that the servo control system can perform CNC machining according to the information of the interpolation point, including: judging the speed extreme value of each point on the machining path based on the preset linear constraints, and determining the speed correlation between each interpolation point by reading the speed data of the first two points, wherein the preset linear constraints include geometric error, normal acceleration jerk limit, tangential speed limit and tangential acceleration jerk limit; based on the preset linear constraints, the tool path data after path planning is read in units of B-spline curves, the time dimension is sequentially integrated into each path segment and interpolated to obtain the machining information required by the servo control system.

[0100] For example, if Figure 7 As shown, in the feed rate planning process of the embodiment of the present application, a five-axis parametric spline curve is first established, and the correlation relationship between the tool path and the spatial physical axis movement is established based on the structural information of the five-axis parallel machining robot.

[0101] Then, the geometric error and the limits of machining process parameters including normal velocity, acceleration, jerk and tangential velocity conditions can be used as constraints to determine the velocity extremes of specific points on the machining path, and the velocity association between planning points can be generated with the tangential acceleration jerk as the constraint. The final velocity extreme can be obtained by combining the velocity conditions of the first two points.

[0102] Secondly, the determination of the interpolation point can be considered. According to the second-order Runge-Kutta method with parameter compensation, the velocity extreme value is judged based on the curve parameters and constraints starting from the initial point, and the next interpolation point is generated based on the velocity extreme value and the interpolation cycle, thereby obtaining the tool tip position and tool axis vector information of the next interpolation point. The above process is repeated for the next interpolation point until the planning and interpolation of the entire machining path are completed.

[0103] Finally, the coordinates of the five physical axes can be determined based on the tool tip point and tool axis vector to complete the trajectory planning and interpolation of the five-axis full parallel robot.

[0104] In some embodiments, the present application may first establish a constraint system, where the feed rate under the extreme geometric constraints is:

[0105]

[0106] Among them, v g (ρ) feed rate under the limit geometric constraint, δ lim It represents the limit value of the set geometric (bow height) error, and T represents the interpolation period.

[0107] Maximum feed rate v under tool axis angular velocity constraint w (u) can be obtained by the following expression:

[0108]

[0109] Among them, w lim Indicates a given angular velocity extreme value.

[0110] Maximum feed rate v under normal acceleration constraint a (ρ) can be expressed as:

[0111]

[0112] Among them, a n.lim represents a given normal acceleration limit.

[0113] Maximum feed rate v under normal jerk constraint j (ρ) can be obtained by the following expression:

[0114]

[0115] Among them, j n,lim Indicates the given extreme value of normal acceleration.

[0116] The velocity correlation between the path segments under the tangential acceleration constraint can be obtained by the following expression:

[0117]

[0118] wherein a t,lim and j t,lim represent the given tangential acceleration extreme value and tangential jerk extreme value respectively, ΔT represents the interpolation period, a(u i ) represents the feed acceleration velocity, v(u i ) represents the feed velocity.

[0119] Next, based on the second order Runge-Kutta formula, the calculation and generation of the interpolation points are completed on the basis of the velocity planning, according to the parameters of the known points (including the curve parameter u k and the velocity v k ) of the known points, the initial value u temp,k+1 of the new interpolation point curve parameter is calculated by using the second order Runge-Kutta method:

[0120]

[0121] wherein u k represents the curve parameter of the known point, v k represents the velocity of the known point, and k1 and k2 represent the feed parameters.

[0122] wherein k1 and k2 are respectively:

[0123]

[0124]

[0125] wherein P' represents the first derivative expression of the B-spline fitting curve.

[0126] On the basis of the initial value of the curve parameter, a parameter compensation amount Δu k+1 is further added to improve the final calculation accuracy, wherein:

[0127]

[0128] wherein the coefficients c1, c2 and c3 are respectively:

[0129] c1 = ||P'(u temp,k+1 ) || 2 ,

[0130] c2 = 2P'(u temp,k+1 ) T ·(P(u temp,k+1 )-P(u k )),

[0131]

[0132] wherein utemp,k+1 Indicates the initial value of the new interpolation point curve parameter

[0133] Therefore, the interpolation point parameter u is finally adopted. k+1 It is composed of two quantities: initial value and compensation value. The expression is as follows:

[0134] u k+1 =u temp,k+1 +Δu k+1 ,

[0135] Among them, u k+1 Indicates the parameters of the interpolation point, u temp,k+1 Indicates the initial value of the new interpolation point curve parameter, Δu k+1 Indicates the parameter compensation amount.

[0136] In summary, in order to achieve more efficient data processing, the embodiment of the present application can combine speed planning and interpolation calculation. After the maximum speed value of the corresponding point is generated through curve information and constraint conditions, the speed value v is combined with the speed value v. k and the fixed interpolation period T and the parameter information u at the corresponding point k , and the parameter u at the next point can be calculated by the second-order Runge-Kutta method with the above parameter compensation k+1 , and then the tool tip position and tool axis vector parameters corresponding to the next point can be calculated. The position information of each drive axis can be inversely solved through the robot structure information. The above operation process is repeated, and the time dimension is sequentially integrated into each path segment and interpolated, realizing real-time speed planning and interpolation.

[0137] According to the tool path and speed planning method of the five-axis parallel machining robot proposed in the embodiment of the present application, the mapping relationship between the tool posture and the length of each drive branch chain can be obtained based on the inverse kinematic model of the five-axis parallel machining robot, and the tool tip point position vector and tool axis vector in the tool position file can be read, the original point sequence of the tool position point file can be preprocessed, and the B-spline curve can be fitted in combination with the symmetric layout strategy and continuity condition to obtain the tool tip point position path, the tool axis vector curve can be normalized to generate the tool axis vector path, and the fitting error of the tool tip point position path and the tool axis vector path can be calculated. If the error requirements are not met, the linear fitting is performed again after iteration, and then the feed speed is planned based on the preset constraint conditions, and discretized according to the preset interpolation period, so that the servo control system can perform CNC machining according to the information of the interpolation point, thereby effectively improving the simplicity of calculation and improving the processing efficiency of speed planning. This solves the problem that the Newton-Raphson iterative optimization technology or quadratic fitting technology used in related technologies causes the tool path calculation to be highly complex, and cannot simultaneously take into account both the high-order continuity of the tool path and the simplicity of calculation, and cannot simultaneously take into account both the planning accuracy and the planning speed.

[0138] Next, the tool path and speed planning device of the five-axis parallel machining robot proposed in the embodiment of the present application will be described with reference to the accompanying drawings.

[0139] Figure 8 It is a block diagram of a tool path and speed planning device for a five-axis parallel machining robot according to an embodiment of the present application.

[0140] like Figure 8 As shown, the tool path and speed planning device 10 of the five-axis parallel machining robot includes: a first acquisition module 100, a reading module 200, a generation module 300, a second acquisition module 400, a calculation module 500, a processing module 600 and a planning module 700.

[0141] Specifically, the first acquisition module 100 is used to obtain the mapping relationship between the tool posture and the length of each drive branch chain based on the inverse kinematics model of the five-axis parallel machining robot.

[0142] The reading module 200 is used to read a series of discrete tool tip point position vectors and tool axis vectors contained in the tool location file to obtain an original point sequence that needs to be fitted.

[0143] The generation module 300 is used to pre-process the original point sequence to be fitted, generate alternative start points and end points of the processed original point sequence, and wrap the original start points and end points in the processed original point sequence.

[0144] The second acquisition module 400 is used to describe the tool tip point position and tool axis vector with target parameters based on the processed original point sequence, and fit the B-spline curve in combination with the symmetric layout strategy and continuity condition, and directly connect the fitted curves to obtain a third-order continuous tool tip point position path. At the same time, the curve is normalized to generate a third-order continuous tool axis vector path.

[0145] The calculation module 500 is used to calculate the fitting error between the tool tip point position path and the tool axis vector path, and determine whether the fitting error meets the error requirement.

[0146] The processing module 600 is used to continue iterating and re-performing linear fitting if the error requirement is not met, until the error requirement is met, so that the fitting error falls within the specified error range.

[0147] The planning module 700 is used to plan the feed rate based on the preset linear constraint conditions, obtain the feed rate curve, and discretize the feed rate curve according to the preset interpolation period, so that the servo control system performs CNC machining according to the information of the interpolation points.

[0148] Optionally, in one embodiment of the present application, the generating module 300 includes: a first setting unit, a second setting unit and a processing unit.

[0149] The first setting unit is used to set the new starting point as a symmetrical point of the original second point with respect to the original first point.

[0150] The second setting unit is used to set the new penultimate point as a symmetrical point of the original penultimate point.

[0151] The processing unit is used to wrap the original starting point and end point in the processed original point sequence after preprocessing, so that the tool processing position of each point is within the error range of the theoretical processing position.

[0152] Optionally, in one embodiment of the present application, the second acquisition module 400 includes: a calculation unit, a first acquisition unit, and a second acquisition unit.

[0153] Among them, the calculation unit is used to combine the third-order continuity constraints and symmetric layout strategy of the tool path cross-segment, and calculate the relative positions of the control points required for the preliminary fitting of the local curve based on every three tool position points.

[0154] The first acquisition unit is used to design a quintic fitting B-spline curve based on the relative positions of the control points and with the intermediate tool position point as the central control point, to obtain a third-order continuous tool tip point position path and normalize the tool axis vector curve.

[0155] The first determining unit is used to obtain a third-order continuous tool axis vector path based on the symmetrical change of the unitization of the tool axis vector curve.

[0156] Optionally, in one embodiment of the present application, the planning module 700 includes: a second determining unit and a second acquiring unit.

[0157] The second determining unit is configured to determine the velocity extreme value of each point on the machining path based on a preset linear constraint condition, and determine the velocity correlation between each interpolation point by reading the velocity data of the first two points, wherein the preset linear constraint condition includes a geometric error, a normal acceleration jerk limit, a tangential velocity limit, and a tangential acceleration jerk limit;

[0158] The second acquisition unit is used to read the tool path data after path planning based on preset linear constraints and in units of B-spline curves, integrate the time dimension into each path segment in sequence and perform interpolation to obtain the processing information required by the servo control system.

[0159] Optionally, in one embodiment of the present application, the parameters of the interpolation point are composed of an initial value and a compensation value, and the expression thereof is as follows:

[0160] u k+1 =u temp,k+1 +Δu k+1 ,

[0161] Among them, u k+1 Indicates the parameters of the interpolation point, u temp,k+1 Indicates the initial value of the new interpolation point curve parameter, Δu k+1 Indicates parameter compensation amount.

[0162] It should be noted that the above explanation of the embodiment of the tool path and speed planning method of the five-axis parallel machining robot is also applicable to the tool path and speed planning device of the five-axis parallel machining robot in this embodiment, and will not be repeated here.

[0163] According to the tool path and speed planning device of the five-axis parallel machining robot proposed in the embodiment of the present application, the mapping relationship between the tool posture and the length of each drive branch chain can be obtained based on the inverse kinematics model of the five-axis parallel machining robot, and the tool tip point position vector and tool axis vector in the tool position file can be read, and the original point sequence of the tool position point file can be preprocessed. The B-spline curve is fitted in combination with the symmetric layout strategy and continuity condition to obtain the tool tip point position path, and the tool axis vector curve is normalized to generate the tool axis vector path, and the fitting error of the tool tip point position path and the tool axis vector path is calculated. If the error requirements are not met, the iteration is continued and the linear fitting is re-performed, and the feed speed is planned based on the preset linear constraint conditions, and discretized according to the preset interpolation period, so that the servo control system can perform CNC machining according to the data information of the interpolation point, thereby effectively improving the simplicity of calculation and improving the processing efficiency of speed planning. This solves the problem that the Newton-Raphson iterative optimization technology or quadratic fitting technology used in related technologies causes the tool path calculation to be highly complex, and cannot simultaneously take into account both the high-order continuity of the tool path and the simplicity of calculation, and cannot simultaneously take into account both the planning accuracy and the planning speed.

[0164] Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include:

[0165] A memory 901 , a processor 902 , and a computer program stored in the memory 901 and executable on the processor 902 .

[0166] When the processor 902 executes the program, the tool path and speed planning method of the five-axis parallel machining robot provided in the above embodiment is implemented.

[0167] Furthermore, the electronic device further includes:

[0168] The communication interface 903 is used for communication between the memory 901 and the processor 902 .

[0169] The memory 901 is used to store computer programs that can be run on the processor 902 .

[0170] The memory 901 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0171] If the memory 901, processor 902, and communication interface 903 are implemented independently, the communication interface 903, memory 901, and processor 902 can be connected to each other via a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 9 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0172] Optionally, in a specific implementation, if the memory 901, the processor 902 and the communication interface 903 are integrated on a chip, the memory 901, the processor 902 and the communication interface 903 can communicate with each other through an internal interface.

[0173] The processor 902 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0174] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the tool path and speed planning method for the five-axis parallel machining robot as described above.

[0175] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0176] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0177] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing a custom logical function or process step, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed in a different order than shown or discussed, including performing functions in a substantially simultaneous manner or in a reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application pertain.

[0178] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or N wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program can be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing it in other suitable ways as necessary, and then storing it in a computer memory.

[0179] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0180] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0181] In addition, the functional units in the various embodiments of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into a module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0182] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present application.

Claims

1. A tool path and speed planning method for a five-axis parallel machining robot, characterized in that: The following steps are involved: Based on the inverse kinematics model of the five-axis parallel machining robot, the mapping relationship between the tool posture and the length of each drive branch chain is obtained; Read a series of discrete tool tip position vectors and tool axis vectors contained in the tool location file to obtain the original point sequence that needs to be fitted; Preprocessing the original point sequence to be fitted, generating alternative starting points and end points of the processed original point sequence, and wrapping the original starting points and end points in the processed original point sequence; Based on the processed original point sequence, the tool tip point position and tool axis vector are described using target parameters, and a B-spline curve is fitted in combination with a symmetric arrangement strategy and a continuity condition. The fitted curves are directly connected to obtain a third-order continuous tool tip point position path, and the tool axis vector curve is normalized to generate a third-order continuous tool axis vector path. Calculating a fitting error between the tool tip point position path and the tool axis vector path, and determining whether the fitting error meets an error requirement; If the error requirement is not met, re-performing linear fitting until the error requirement is met, so that the fitting error falls within the specified error range; Feed rate planning is performed based on preset linear constraints to obtain a feed rate curve, and the feed rate curve is discretized according to a preset interpolation period, so that the servo control system performs numerical control machining according to information of the interpolation points.

2. The method according to claim 1, characterized in that Preprocessing the original point sequence to be fitted, generating a replacement start point and an end point of the processed original point sequence, and wrapping the original start point and the end point in the processed original point sequence, includes: Set the new starting point to be the symmetrical point of the original second point relative to the original first point; Set the new penultimate point to be the symmetrical point of the original penultimate point; After preprocessing, the original starting point and end point will be wrapped in the processed original point sequence, so that the tool processing position of each point is within the error range of the theoretical processing position.

3. The method according to claim 1, characterized in that Based on the processed original point sequence, the tool tip point position and tool axis vector are described using target parameters, and a B-spline curve is fitted in combination with a symmetric arrangement strategy and a continuity condition. The fitted curves are directly connected to obtain a third-order continuous tool tip point position path. At the same time, the tool axis vector curve is normalized to generate a third-order continuous tool axis vector path, including: Combining the third-order continuity constraints and symmetric layout strategy of the tool path cross-segment, the relative positions of the control points required for the preliminary fitting of the local curve are calculated based on every three tool position points; Based on the relative positions of the control points, a quintic fitting B-spline curve is designed with the middle tool position point as the central control point to obtain a third-order continuous tool tip position path while normalizing the tool axis vector curve; Based on the symmetrical change of the unitized tool axis vector curve, the third-order continuous tool axis vector path is obtained.

4. The method according to claim 1, wherein The feed rate planning is performed based on the preset linear constraint condition to obtain a feed rate curve, and the feed rate curve is discretized according to a preset interpolation period so that the servo control system performs CNC machining according to the information of the interpolation point, including: Based on the preset linear constraints, a velocity extreme value is judged for each point on the machining path, and the velocity correlation between each interpolation point is determined by reading the velocity data of the first two points, wherein the preset linear constraints include geometric error, normal acceleration jerk limit, tangential velocity limit, and tangential acceleration jerk limit; Based on the preset linear constraints, the tool path data after path planning is read in units of B-spline curves, and the time dimension is sequentially integrated into each path segment and interpolated to obtain the processing information required by the servo control system.

5. The method according to claim 4, characterized in that The parameters of the interpolation point are composed of the initial value and the compensation value, and the expression is as follows: u k+1 =u temp,k+1 +Δu k+1 , Among them, u k+1 Indicates the parameters of the interpolation point, u temp,k+1 Indicates the initial value of the new interpolation point curve parameter, Δu k+1 Indicates parameter compensation amount.

6. A tool path and speed planning device for a five-axis parallel machining robot, characterized in that: include: The first acquisition module is used to obtain the mapping relationship between the tool posture and the length of each drive branch chain based on the inverse kinematics model of the five-axis parallel machining robot; The reading module is used to read a series of discrete tool tip position vectors and tool axis vectors contained in the tool location file to obtain the original point sequence that needs to be fitted; A generation module is used to pre-process the original point sequence to be fitted, generate a replacement start point and end point of the processed original point sequence, and wrap the original start point and end point in the original point sequence; A second acquisition module is configured to describe the tool tip point position and tool axis vector using target parameters based on the processed original point sequence, fit a B-spline curve in combination with a symmetric arrangement strategy and a continuity condition, directly connect the fitted curves to obtain a third-order continuous tool tip point position path, and normalize the tool axis vector curve to generate a third-order continuous tool axis vector path; a calculation module, configured to calculate a fitting error between the tool tip point position path and the tool axis vector path, and determine whether the fitting error meets an error requirement; a processing module, configured to re-perform linear fitting if the error requirement is not met, until the error requirement is met, so that the fitting error falls within a specified error range; The planning module is used to plan the feed rate based on the preset linear constraint conditions to obtain the feed rate curve, and discretize the feed rate curve according to the preset interpolation cycle, so that the servo control system performs CNC machining according to the information of the interpolation points.

7. The device according to claim 6, characterized in that The generation module includes: A first setting unit is used to set a new starting point as a symmetrical point of the original second point with respect to the original first point; The second setting unit is used to set the new penultimate point to be the symmetrical point of the original penultimate point; The processing unit is used to wrap the original starting point and end point in the original point sequence after preprocessing, so that the tool processing position of each point is within the error range of the theoretical processing position.

8. The device according to claim 6, characterized in that The second acquisition module includes: A calculation unit is used to combine the third-order continuity constraint conditions and symmetric layout strategy of the tool path cross-segment to calculate the relative positions of the control points required for the preliminary fitting of the local curve based on every three tool position points; A first acquisition unit is configured to design a quintic fitting B-spline curve based on the relative positions of the control points and with the intermediate tool position point as the central control point, thereby obtaining a third-order continuous tool tip position path and normalizing the tool axis vector curve; The first determining unit is configured to obtain the third-order continuous tool axis vector path based on the symmetrical change of the unitized tool axis vector curve.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the tool path and speed planning method for a five-axis parallel machining robot as described in any one of claims 1 to 5.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the tool path and speed planning method of the five-axis parallel machining robot according to any one of claims 1 to 5.

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