Post-processing method and system of numerical control machine tool
By combining kinematic equations of tool and workpiece motion chains, solving the inverse value of Jacobian matrix, the problem of insufficient versatility and scalability of post-processing methods of CNC machine tools is solved, and is suitable for a variety of CNC machine tools structures.
Patent Information
- Application Number
- CN202411096764.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-12
- Publication Date
- 2024-12-31
AI Technical Summary
The existing CNC machine tool post-processing methods are sensitive to structural changes, have poor versatility and scalability, and are difficult to adapt to when facing special CNC machine tools.
By combining the tool motion chain and the workpiece motion chain into the machine tool motion chain, kinematic equations are constructed, the Jacobian matrix is solved and the computer bed axis value is used using its inverse value, which is suitable for different types of CNC machine tools.
It realizes the universality and expansion of different types of CNC machine tools, avoids the trouble of re-deriving formulas due to structural changes, and is suitable for special CNC machine tools.
Smart Images
Figure CN119225291A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of post-processing methods for numerically controlled machine tools, and in particular to a post-processing method and system for numerically controlled machine tools. Background Art
[0002] As the manufacturing industry continues to develop towards automation and intelligence, CNC machine tools are widely used in aerospace, automobiles, molds, medical devices and other fields that require high processing precision. Through CNC machine tool post-processing methods, the tool path data generated in the Computer Aided Manufacturing (CAM) system can be converted into NC code that can be executed by CNC machine tools.
[0003] At present, different post-processing methods are configured for different types of CNC machine tools. For example: for three-axis CNC machine tools, since they do not have a rotating axis, the tool path can be directly converted into the axis value of the machine tool's xyz axis; for four-axis CNC machine tools, it is necessary to first distinguish whether its fourth axis is located on the workpiece side or the tool side, and then convert the tool path into the axis value of the four-axis CNC machine tool through different calculation formulas; for five-axis CNC machine tools, since they have two rotating axes and there are multiple options for the positions of the two rotating axes, five-axis CNC machine tools can be divided into three basic types: double swing head type, double turntable type, and swing head turntable type. In addition, there are special five-axis CNC machine tools that are non-orthogonal or have angle heads, and their post-processing methods require additional development and verification.
[0004] Obviously, the existing post-processing methods for CNC machine tools are highly dependent on the structure of CNC machine tools. When the structure of CNC machine tools changes, the formulas in the corresponding post-processing methods need to be re-derived and reconfigured, and their versatility and scalability are poor, which is particularly obvious when facing special CNC machine tools. Summary of the invention
[0005] To this end, the technical problem to be solved by the present invention is to overcome the problem of poor versatility and expansibility of the CNC machine tool post-processing method in the prior art, and to provide a CNC machine tool post-processing method and system that is suitable for different types of CNC machine tools and has good versatility and expansibility.
[0006] In a first aspect, in order to solve the above technical problems, the present invention provides a post-processing method for a CNC machine tool, comprising the following steps:
[0007] The two kinematic chains of the CNC machine tool are respectively determined as the tool kinematic chain and the workpiece kinematic chain;
[0008] For all components between the origin of the machine tool coordinate system and the tool that may change the position and posture of the tool, the tool homogeneous matrix is used to represent the position and posture of the tool in the world coordinate system; the kinematic equation of the tool motion chain is constructed based on the tool homogeneous matrix;
[0009] For all components between the origin of the machine tool coordinate system and the workpiece that may change the posture of the workpiece, the posture of the workpiece in the world coordinate system is represented by a workpiece homogeneous matrix; the kinematic equation of the workpiece motion chain is constructed based on the workpiece homogeneous matrix;
[0010] The tool kinematic chain and the workpiece kinematic chain are combined into a machine tool kinematic chain, wherein the machine tool kinematic chain takes the workpiece coordinate system as a starting point and the tool coordinate system as an end point; the kinematic equation of the machine tool kinematic chain is constructed based on the kinematic equation of the tool kinematic chain and the kinematic equation of the workpiece kinematic chain to obtain the position and posture of the tool in the workpiece coordinate system;
[0011] The Jacobian matrix of the current axis value of the machine tool kinematic chain is obtained based on the current posture and target posture of the tool in the workpiece coordinate system; the Jacobian matrix is inverted to obtain the current axis value of the machine tool kinematic chain.
[0012] In one embodiment of the present invention, when the Jacobian matrix is inverted, if the Jacobian matrix is not a full-rank square matrix, the generalized inverse of the Jacobian matrix is used to obtain the current axis value of the machine tool kinematic chain.
[0013] In one embodiment of the present invention, when the generalized inverse of the Jacobian matrix is used, a numerical iterative solution is performed to obtain the current axis value of the machine tool kinematic chain.
[0014] In one embodiment of the present invention, a method for obtaining the Jacobian matrix of the current axis value of the machine tool kinematic chain based on the current posture and target posture of the tool in the workpiece coordinate system is:
[0015] dT = J(q)dq;
[0016] Among them, dT is the differential of the current posture and target posture of the tool in the workpiece coordinate system, J(q) is the Jacobian matrix of the current axis value of the machine tool motion chain, and dq is the differential of the current axis value q of the machine tool motion chain.
[0017] In one embodiment of the present invention, the kinematic equation of the tool motion chain is:
[0018]
[0019] The kinematic equation of the workpiece kinematic chain is:
[0020]
[0021] Among them, T trepresents the position of the tool in the world coordinate system, T0 is the position of the origin of the machine coordinate system in the world coordinate system, and the superscript t indicates that the component corresponding to the homogeneous matrix is located on the tool motion chain. are the first to Nth components represented by the tool homogeneous matrix, and the first to Nth components are sequentially sorted from the parent node to the child node; T w represents the position of the workpiece in the world coordinate system, and the superscript w indicates that the component corresponding to the homogeneous matrix is located on the workpiece kinematic chain. The first to Mth components are represented by the workpiece homogeneous matrix, and the first to Mth components are sequentially sorted from the parent node to the child node.
[0022] In one embodiment of the present invention, the kinematic equation of the machine tool kinematic chain is:
[0023]
[0024] Among them, T t w is the position of the tool in the workpiece coordinate system, and the superscript -1 indicates the inverse.
[0025] In one embodiment of the present invention, for a component whose posture is represented by the tool homogeneous matrix, when the component is a translation axis, the tool homogeneous matrix of the component adds a translational degree of freedom; for a component whose posture is represented by the workpiece homogeneous matrix, when the component is a translation axis, the workpiece homogeneous matrix of the component also adds a translational degree of freedom; the translational degree of freedom T trans for:
[0026]
[0027] Among them, when the translation axis is the x-axis, dy=dz=0, dx is the current axis value; when the translation axis is the y-axis, dx=dz=0, dy is the current axis value; when the translation axis is the z-axis, dx=dy=0, dz is the current axis value.
[0028] In one embodiment of the present invention, for a component whose posture is represented by the tool homogeneous matrix, when the component is a rotation axis, the tool homogeneous matrix of the component adds a rotational degree of freedom; for a component whose posture is represented by the workpiece homogeneous matrix, when the component is a rotation axis, the workpiece homogeneous matrix of the component also adds a rotational degree of freedom; the rotational degree of freedom T rot for:
[0029]
[0030] Wherein, R is a 3*3 rotation matrix, which represents the position transformation of the component relative to its parent node component caused by its own rotation.
[0031] In one embodiment of the present invention, for a component whose posture is represented by the tool homogeneous matrix, when the component only changes the relative position relationship between itself and its parent node component, the tool homogeneous matrix of the component is represented by the relative position relationship between the component and its parent node component; for a component whose posture is represented by the workpiece homogeneous matrix, when the component only changes the relative position relationship between itself and its parent node component, the workpiece homogeneous matrix of the component is also represented by the relative position relationship between the component and its parent node component.
[0032] In a second aspect, in order to solve the above technical problems, the present invention further provides a post-processing system for a CNC machine tool, comprising:
[0033] In the initial module, the two kinematic chains of the CNC machine tool are determined as the tool kinematic chain and the workpiece kinematic chain;
[0034] The tool motion chain module uses a tool homogeneous matrix to represent the position of all components between the origin of the machine tool coordinate system and the tool that may change the position of the tool in the world coordinate system; and constructs the kinematic equation of the tool motion chain based on the tool homogeneous matrix;
[0035] A workpiece kinematic chain module, for all components between the origin of the machine tool coordinate system and the workpiece that may change the posture of the workpiece, uses a workpiece homogeneous matrix to represent their posture in the world coordinate system; and constructs the kinematic equation of the workpiece kinematic chain based on the workpiece homogeneous matrix;
[0036] A machine tool kinematic chain module is used to combine the tool kinematic chain and the workpiece kinematic chain into a machine tool kinematic chain, wherein the machine tool kinematic chain takes the workpiece coordinate system as a starting point and the tool coordinate system as an end point; a kinematic equation of the machine tool kinematic chain is constructed based on the kinematic equation of the tool kinematic chain and the kinematic equation of the workpiece kinematic chain to obtain the position and posture of the tool in the workpiece coordinate system;
[0037] The axis value calculation module obtains the Jacobian matrix of the current axis value of the machine tool motion chain based on the current posture and target posture of the tool in the workpiece coordinate system; inverts the Jacobian matrix to obtain the current axis value of the machine tool motion chain.
[0038] The above technical solution of the present invention has the following beneficial effects compared with the prior art:
[0039] The present invention provides a post-processing method and system for a numerically controlled machine tool, which combines a tool motion chain and a workpiece motion chain into a machine tool motion chain, constructs a kinematic equation of the machine tool motion chain to obtain the position and posture of the tool in a workpiece coordinate system, obtains the Jacobian matrix of the current axis value of the machine tool motion chain based on the current position and target position of the tool in the workpiece coordinate system, and then inverts the Jacobian matrix to obtain the current axis value of the machine tool motion chain. The method is suitable for different types of numerically controlled machine tools and has good versatility and expansibility. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.
[0041] Figure 1 A step diagram of a post-processing method for a CNC machine tool in a preferred embodiment of the present invention;
[0042] Figure 2 A schematic diagram of a coordinate system taking a BC swing head turntable five-axis CNC machine tool as an example in a preferred embodiment of the present invention;
[0043] Figure 3 It is a module diagram of a post-processing system of a CNC machine tool in an embodiment of the present invention. DETAILED DESCRIPTION
[0044] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0045] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.
[0046] The existing post-processing methods for CNC machine tools are highly dependent on the structure of CNC machine tools. When the structure of CNC machine tools changes, the formulas in the corresponding post-processing methods need to be re-derived and reconfigured. They have poor versatility and scalability, which is particularly evident when facing special CNC machine tools.
[0047] To this end, an embodiment of the present application provides a post-processing method and system for a CNC machine tool.
[0048] Embodiment 1
[0049] This embodiment provides a post-processing method for a CNC machine tool. Figure 1 As shown, the following steps are included:
[0050] The two kinematic chains of the CNC machine tool are respectively determined as the tool kinematic chain and the workpiece kinematic chain;
[0051] For all components between the origin of the machine tool coordinate system and the tool that may change the position and posture of the tool, the tool homogeneous matrix is used to represent the position and posture of the tool in the world coordinate system; the kinematic equation of the tool motion chain is constructed based on the tool homogeneous matrix;
[0052] For all components between the origin of the machine tool coordinate system and the workpiece that may change the posture of the workpiece, the posture of the workpiece in the world coordinate system is represented by a workpiece homogeneous matrix; the kinematic equation of the workpiece motion chain is constructed based on the workpiece homogeneous matrix;
[0053] The tool kinematic chain and the workpiece kinematic chain are combined into a machine tool kinematic chain, wherein the machine tool kinematic chain takes the workpiece coordinate system as a starting point and the tool coordinate system as an end point; the kinematic equation of the machine tool kinematic chain is constructed based on the kinematic equation of the tool kinematic chain and the kinematic equation of the workpiece kinematic chain to obtain the position and posture of the tool in the workpiece coordinate system;
[0054] The Jacobian matrix of the current axis value of the machine tool kinematic chain is obtained based on the current posture and target posture of the tool in the workpiece coordinate system; the Jacobian matrix is inverted to obtain the current axis value of the machine tool kinematic chain.
[0055] The present embodiment provides a post-processing method for a CNC machine tool, which combines the tool motion chain and the workpiece motion chain into a machine tool motion chain, constructs the kinematic equation of the machine tool motion chain based on the kinematic equation of the tool motion chain and the kinematic equation of the workpiece motion chain, obtains the position and posture of the tool in the workpiece coordinate system, and then obtains the Jacobian matrix of the current axis value of the machine tool motion chain based on the current position and target position of the tool in the workpiece coordinate system, and inverts the Jacobian matrix to obtain the current axis value of the machine tool motion chain. The processing method is applicable to different types of CNC machine tools, does not require formula derivation and analytical expression based on the specific type of the data machine tool, and has good versatility and extensibility.
[0056] Next, a post-processing method for a CNC machine tool is introduced in detail:
[0057] 1. Principle of the method
[0058] Step 1
[0059] Specifically, the two kinematic chains of the CNC machine tool are respectively determined as a tool kinematic chain and a workpiece kinematic chain.
[0060] Specifically, the tool kinematic chain includes the positions and postures of all components between the origin of the machine tool coordinate system and the tool that may change the tool position and posture, and the workpiece kinematic chain includes the positions and postures of all components between the origin of the machine tool coordinate system and the workpiece that may change the workpiece position and posture;
[0061] Among them, the starting point of the tool motion chain and the starting point of the workpiece motion chain are both the origin of the machine tool coordinate system, the end of the tool motion chain is the position of the tool in the world coordinate system, and the end of the workpiece motion chain is the position of the workpiece in the world coordinate system.
[0062] Furthermore, for all components between the origin of the machine tool coordinate system and the tool that may change the posture of the tool, the tool homogeneous matrix is used to represent their posture in the world coordinate system; for all components between the origin of the machine tool coordinate system and the workpiece that may change the posture of the workpiece, the workpiece homogeneous matrix is used to represent their posture in the world coordinate system.
[0063] It should be noted that steps 2 and 3 described below are performed simultaneously and have no temporal sequence.
[0064] Step 2
[0065] Specifically, the kinematic equation of the tool motion chain is constructed based on the tool homogeneous matrix.
[0066] Optionally, for a component whose posture is represented by the tool homogeneous matrix, its tool homogeneous matrix is represented by T i t ; Wherein, the subscript i represents the i-th component, and the superscript t represents that the component is located on the tool motion chain.
[0067] Specifically, for a component whose position is represented by the tool homogeneous matrix, when the component only changes the relative position relationship between itself and its parent node component, the tool homogeneous matrix of the component uses the relative position relationship T between the component and its parent node component. i t(i-1) express.
[0068] Specifically, for a component whose posture is represented by the tool homogeneous matrix, when the component is a translation axis, the tool homogeneous matrix of the component adds a translation degree of freedom; the translation degree of freedom T trans for:
[0069]
[0070] Wherein, when the translation axis is the x-axis, dy=dz=0, dx is the current axis value; when the translation axis is the y-axis, dx=dz=0, dy is the current axis value; when the translation axis is the z-axis, dx=dy=0, dz is the current axis value;
[0071] Furthermore, the tool homogeneous matrix of this component is T i t =T i t(i-1) Ttrans .
[0072] Specifically, for a component whose position is represented by the tool homogeneous matrix, when the component is a rotation axis, the tool homogeneous matrix of the component adds a rotational degree of freedom; the rotational degree of freedom T rot for:
[0073]
[0074] Wherein, R is a 3*3 rotation matrix, which represents the position transformation of the component relative to its parent node component caused by its own rotation;
[0075] Furthermore, the tool homogeneous matrix of this component is T i t =T i t(i-1) T rot .
[0076] Specifically, the kinematic equation of the tool motion chain is:
[0077]
[0078] Among them, T t represents the position of the tool in the world coordinate system, T0 is the position of the origin of the machine tool coordinate system in the world coordinate system, The first to Nth components are represented by the tool homogeneous matrix, and the first to Nth components are sequentially sorted from the parent node to the child node.
[0079] Step 3
[0080] Specifically, the kinematic equation of the workpiece motion chain is constructed based on the workpiece homogeneous matrix.
[0081] Optionally, for a component whose posture is represented by the workpiece homogeneous matrix, its workpiece homogeneous matrix is represented as The subscript j indicates the jth component, and the superscript w indicates that the component is located on the workpiece kinematic chain.
[0082] Specifically, for a component whose posture is represented by the workpiece homogeneous matrix, when the component only changes the relative position relationship between itself and its parent node component, the workpiece homogeneous matrix of the component uses the relative position relationship between the component and its parent node component. express.
[0083] Specifically, for a component whose posture is represented by the workpiece homogeneous matrix, when the component is a translation axis, the workpiece homogeneous matrix of the component adds a translational degree of freedom T trans , the workpiece homogeneous matrix of this component is
[0084] Specifically, for a component whose posture is represented by the workpiece homogeneous matrix, when the component is a rotation axis, the workpiece homogeneous matrix of the component adds one rotational degree of freedom T rot , the workpiece homogeneous matrix of this component is
[0085] Specifically, the kinematic equation of the workpiece motion chain is:
[0086]
[0087] Among them, T w represents the position and posture of the workpiece in the world coordinate system, The first to Mth components are represented by the workpiece homogeneous matrix, and the first to Mth components are sequentially sorted from the parent node to the child node.
[0088] Step 4
[0089] Specifically, the tool motion chain and the workpiece motion chain are combined into a machine tool motion chain, and the machine tool motion chain starts from the workpiece coordinate system and ends at the tool coordinate system; wherein the origin of the workpiece coordinate system is the workpiece, and the origin of the tool coordinate system is the tool.
[0090] Specifically, the kinematic equation of the machine tool kinematic chain is constructed based on the kinematic equation of the tool kinematic chain and the kinematic equation of the workpiece kinematic chain. The kinematic equation of the machine tool kinematic chain is:
[0091]
[0092] Among them, T t w is the position of the tool in the workpiece coordinate system, and the superscript -1 indicates the inverse.
[0093] Step 5
[0094] Specifically, the Jacobian matrix of the current axis value of the machine tool kinematic chain is obtained based on the current posture and target posture of the tool in the workpiece coordinate system; the Jacobian matrix is inverted to obtain the current axis value of the machine tool kinematic chain.
[0095] Specifically, the method for obtaining the Jacobian matrix of the current axis value of the machine tool kinematic chain based on the current posture and target posture of the tool in the workpiece coordinate system is:
[0096] dT = J(q)dq;
[0097] Among them, dT is the differential of the current posture and target posture of the tool in the workpiece coordinate system, J(q) is the Jacobian matrix of the current axis value of the machine tool motion chain, and dq is the differential of the current axis value q of the machine tool motion chain.
[0098] Furthermore, when inverting the Jacobian matrix, if the Jacobian matrix is not a full-rank square matrix, the generalized inverse J of the Jacobian matrix is used. + (q) obtaining the current axis value of the machine tool kinematic chain by:
[0099] dq=J + (q)dT;
[0100] Furthermore, considering the use of the generalized inverse of the Jacobian matrix J + (q) is an approximation of the inverse of the Jacobian matrix, using the generalized inverse J of the Jacobian matrix + (q), an iterative solution is performed until the solution meets the required accuracy, thereby obtaining the current axis value of the machine tool kinematic chain.
[0101] 2. Examples
[0102] Next, a BC swing head turntable five-axis CNC machine tool is taken as an example, and the post-processing method for a CNC machine tool described in this embodiment is used to post-process it.
[0103] For details, please refer to Figure 2 As shown, there are x-axis, y-axis, z-axis and b-axis on the tool side of the machine tool, and the x-axis is offset by 0 relative to the origin of the machine coordinate system of the machine tool, the y-axis is offset by 0 relative to the x-axis, the z-axis is offset by 0 relative to the y-axis, the b-axis is offset by 250 mm along the z-axis direction relative to the z-axis, and the tool of the machine tool is offset by 250 mm in the opposite direction of the z-axis relative to the b-axis.
[0104] Furthermore, the kinematic equation of the tool motion chain of the machine tool is:
[0105]
[0106] Among them, θ b is the rotation angle of the b-axis.
[0107] Specifically, Figure 2 As shown, there is a c-axis on the workpiece side of the machine tool, and the c-axis is offset 500 mm in the opposite direction of the z-axis relative to the origin of the machine tool coordinate system, and the workpiece of the machine tool has no offset relative to the c-axis.
[0108] Furthermore, the kinematic equation of the workpiece motion chain of the machine tool is:
[0109]
[0110] Among them, θ c is the rotation angle of the c-axis.
[0111] Furthermore, the tool kinematic chain of the machine tool is combined with the workpiece kinematic chain to obtain the machine tool kinematic chain of the machine tool, and its kinematic equation is:
[0112]
[0113] For example, if all axes of the machine tool are at zero, then:
[0114] dx=dy=dz=0,θ b =θ c =0;
[0115] Substituting it into the kinematic equation of the machine tool kinematic chain of the machine tool, the current position of the tool in the workpiece coordinate system is obtained as:
[0116]
[0117] Specifically, this means that the origin of the tool coordinate system is located at the current position (0, 0, 500) of the workpiece coordinate system, and the current tool axis direction is (0, 0, 1).
[0118] Exemplarily, the origin of the tool coordinate system is located at the target pose of the workpiece coordinate system (-250, 0, 750), and the target tool axis direction is (1, 0, 0), then the target pose of the tool in the workpiece coordinate system is:
[0119]
[0120] Furthermore, the target position of the tool and the current pose T t w The differential of is:
[0121]
[0122] Furthermore, the Jacobian matrix of the current axis value of the machine tool kinematic chain of the machine tool is:
[0123]
[0124] Furthermore, the generalized inverse of the Jacobian matrix is used and numerical iteration is performed until the current axis value of the machine tool kinematic chain of the BC swing head turntable five-axis CNC machine tool that meets the accuracy requirements is obtained.
[0125] Embodiment 2
[0126] This embodiment provides a post-processing system for a CNC machine tool. Figure 3 As shown, including:
[0127] In the initial module, the two kinematic chains of the CNC machine tool are determined as the tool kinematic chain and the workpiece kinematic chain;
[0128] The tool motion chain module uses a tool homogeneous matrix to represent the position of all components between the origin of the machine tool coordinate system and the tool that may change the position of the tool in the world coordinate system; and constructs the kinematic equation of the tool motion chain based on the tool homogeneous matrix;
[0129] A workpiece kinematic chain module, for all components between the origin of the machine tool coordinate system and the workpiece that may change the posture of the workpiece, uses a workpiece homogeneous matrix to represent their posture in the world coordinate system; and constructs the kinematic equation of the workpiece kinematic chain based on the workpiece homogeneous matrix;
[0130] A machine tool kinematic chain module is used to combine the tool kinematic chain and the workpiece kinematic chain into a machine tool kinematic chain, wherein the machine tool kinematic chain takes the workpiece coordinate system as a starting point and the tool coordinate system as an end point; a kinematic equation of the machine tool kinematic chain is constructed based on the kinematic equation of the tool kinematic chain and the kinematic equation of the workpiece kinematic chain to obtain the position and posture of the tool in the workpiece coordinate system;
[0131] The axis value calculation module obtains the Jacobian matrix of the current axis value of the machine tool motion chain based on the current posture and target posture of the tool in the workpiece coordinate system; inverts the Jacobian matrix to obtain the current axis value of the machine tool motion chain.
[0132] For an introduction to a post-processing system for a CNC machine tool provided in this embodiment, please refer to the first embodiment, and this embodiment will not be described in detail here.
[0133] This embodiment provides a post-processing system for a CNC machine tool, which has the same beneficial effects as the above-mentioned post-processing method for a CNC machine tool.
[0134] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.
[0135] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.
[0136] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.
[0137] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.
[0138] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.
Claims
1. A post-processing method for a CNC machine tool, characterized in that: The following steps are involved: The two kinematic chains of the CNC machine tool are respectively determined as the tool kinematic chain and the workpiece kinematic chain; For all components between the origin of the machine tool coordinate system and the tool that may change the position and posture of the tool, the tool homogeneous matrix is used to represent the position and posture of the tool in the world coordinate system; the kinematic equation of the tool motion chain is constructed based on the tool homogeneous matrix; For all components between the origin of the machine tool coordinate system and the workpiece that may change the posture of the workpiece, the posture of the workpiece in the world coordinate system is represented by a workpiece homogeneous matrix; the kinematic equation of the workpiece motion chain is constructed based on the workpiece homogeneous matrix; The tool kinematic chain and the workpiece kinematic chain are combined into a machine tool kinematic chain, wherein the machine tool kinematic chain starts from the workpiece coordinate system and ends at the tool coordinate system; The kinematic equation of the machine tool kinematic chain is constructed based on the kinematic equation of the tool kinematic chain and the kinematic equation of the workpiece kinematic chain to obtain the position and posture of the tool in the workpiece coordinate system; Obtaining the Jacobian matrix of the current axis value of the machine tool kinematic chain based on the current posture and target posture of the tool in the workpiece coordinate system; The Jacobian matrix is inverted to obtain the current axis value of the machine tool kinematic chain.
2. A post-processing method for a CNC machine tool according to claim 1, characterized in that: When the Jacobian matrix is inverted, if the Jacobian matrix is not a full-rank square matrix, the generalized inverse of the Jacobian matrix is used to obtain the current axis value of the machine tool kinematic chain.
3. A post-processing method for a CNC machine tool according to claim 2, characterized in that: When the generalized inverse of the Jacobian matrix is used, a numerical iterative solution is performed to obtain the current axis value of the machine tool kinematic chain.
4. A post-processing method for a CNC machine tool according to claim 1, characterized in that: The method for obtaining the Jacobian matrix of the current axis value of the machine tool kinematic chain based on the current posture and target posture of the tool in the workpiece coordinate system is: dT = J(q)dq; Among them, dT is the differential of the current posture and target posture of the tool in the workpiece coordinate system, J(q) is the Jacobian matrix of the current axis value of the machine tool motion chain, and dq is the differential of the current axis value q of the machine tool motion chain.
5. The post-processing method of a CNC machine tool according to claim 1, characterized in that: The kinematic equation of the tool motion chain is: The kinematic equation of the workpiece kinematic chain is: Among them, T t represents the position of the tool in the world coordinate system, T0 is the position of the origin of the machine coordinate system in the world coordinate system, and the superscript t indicates that the component corresponding to the homogeneous matrix is located on the tool motion chain. are the first to Nth components represented by the tool homogeneous matrix, and the first to Nth components are sequentially sorted from the parent node to the child node; T w represents the position of the workpiece in the world coordinate system, and the superscript w indicates that the component corresponding to the homogeneous matrix is located on the workpiece kinematic chain. The first to Mth components are represented by the workpiece homogeneous matrix, and the first to Mth components are sequentially sorted from the parent node to the child node.
6. A post-processing method for a CNC machine tool according to claim 5, characterized in that: The kinematic equation of the machine tool kinematic chain is: in, is the position of the tool in the workpiece coordinate system, and the superscript -1 indicates the inverse.
7. A post-processing method for a CNC machine tool according to claim 1, characterized in that: For a component whose posture is represented by the tool homogeneous matrix, when the component is a translation axis, the tool homogeneous matrix of the component adds a translational degree of freedom; for a component whose posture is represented by the workpiece homogeneous matrix, when the component is a translation axis, the workpiece homogeneous matrix of the component also adds a translational degree of freedom; the translational degree of freedom T trans for: Among them, when the translation axis is the x-axis, dy=dz=0, dx is the current axis value; when the translation axis is the y-axis, dx=dz=0, dy is the current axis value; when the translation axis is the z-axis, dx=dy=0, dz is the current axis value.
8. The post-processing method of a CNC machine tool according to claim 1, characterized in that: For a component whose posture is represented by the tool homogeneous matrix, when the component is a rotation axis, the tool homogeneous matrix of the component adds a rotational degree of freedom; for a component whose posture is represented by the workpiece homogeneous matrix, when the component is a rotation axis, the workpiece homogeneous matrix of the component also adds a rotational degree of freedom; the rotational degree of freedom T rot for: Wherein, R is a 3*3 rotation matrix, which represents the position transformation of the component relative to its parent node component caused by its own rotation.
9. A post-processing method for a CNC machine tool according to claim 1, characterized in that: For a component whose position is represented by the tool homogeneous matrix, when the component only changes the relative position relationship between itself and its parent node component, the tool homogeneous matrix of the component is represented by the relative position relationship between the component and its parent node component; For a component whose posture is represented by the workpiece homogeneous matrix, when the component only changes the relative position relationship between itself and its parent node component, the workpiece homogeneous matrix of the component is also represented by the relative position relationship between the component and its parent node component.
10. A post-processing system for a CNC machine tool, characterized in that: include: In the initial module, the two kinematic chains of the CNC machine tool are determined as the tool kinematic chain and the workpiece kinematic chain; The tool motion chain module uses a tool homogeneous matrix to represent the position of all components between the origin of the machine tool coordinate system and the tool that may change the position of the tool in the world coordinate system; and constructs the kinematic equation of the tool motion chain based on the tool homogeneous matrix; A workpiece kinematic chain module, for all components between the origin of the machine tool coordinate system and the workpiece that may change the posture of the workpiece, uses a workpiece homogeneous matrix to represent their posture in the world coordinate system; and constructs the kinematic equation of the workpiece kinematic chain based on the workpiece homogeneous matrix; A machine tool kinematic chain module, which combines the tool kinematic chain and the workpiece kinematic chain into a machine tool kinematic chain, wherein the machine tool kinematic chain takes the workpiece coordinate system as a starting point and the tool coordinate system as an end point; The kinematic equation of the machine tool kinematic chain is constructed based on the kinematic equation of the tool kinematic chain and the kinematic equation of the workpiece kinematic chain to obtain the position and posture of the tool in the workpiece coordinate system; An axis value calculation module, which obtains the Jacobian matrix of the current axis value of the machine tool kinematic chain based on the current posture and target posture of the tool in the workpiece coordinate system; The Jacobian matrix is inverted to obtain the current axis value of the machine tool kinematic chain.