Virtual assembly and anti-collision simulation method for double-swing-head five-axis numerical control machine tool

Abstract

The invention discloses a virtual assembly and anti-collision simulation method for a double-swing-head five-axis numerical control machine tool, and the method comprises the following steps: S1, building a geometric model of the double-swing-head five-axis numerical control machine tool based on a machine tool kinematic model, and the geometric model comprises parameterized three-dimensional models of a main shaft part, a swing head mechanism, a workbench and a machine tool body; s2, according to the constraint relation of the kinematic chains of the machine tool, an assembly hierarchical relation is established in the virtual environment, and virtual assembly of all parts is achieved through dynamic constraint driving; s3, on the basis of a machine tool kinematics forward and inverse solution algorithm, simulating the motion trail of the double swing heads in the five-axis linkage process; s4, through a real-time collision detection algorithm, detecting interference conditions among the cutter, the swing head, the workpiece, the clamp and the machine tool body, and generating an anti-collision early warning signal; and S5, optimizing a motion path of the machine tool in combination with a simulation result, and outputting a collision-free machining code. The assembly precision can be improved, and the physical debugging cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of CNC machine tool simulation, in particular to a virtual assembly and collision avoidance simulation method for a double-swing-head five-axis CNC machine tool. Background Art

[0002] Five-axis CNC machine tools are widely used in aerospace, precision molds, and other fields due to their ability to process complex surfaces with high precision and efficiency. Dual-swing five-axis machine tools (i.e., machines with both rotating axes concentrated at the spindle end) have become essential for high-end machining due to their greater workspace flexibility. However, the dual-swing structure also introduces increased kinematic complexity, making virtual assembly verification and machining collision avoidance simulation key technical challenges.

[0003] 1. Deficiencies of existing virtual assembly technology

[0004] Traditional machine tool assembly relies on physical prototype debugging, which has the problems of high cost and long cycle. Although virtual assembly technology has been introduced in recent years, it still has the following shortcomings:

[0005] Static assembly models lack kinematic constraints: Existing methods are mostly based on static three-dimensional model assembly, without considering the dynamic interference problem of machine tools in actual movement, resulting in large deviations between simulation results and actual operation.

[0006] Assembly error transmission is not quantified: The geometric errors of the double-swing head structure (such as A / C-axis rotation accuracy and spindle runout) will accumulate during the assembly process, but the existing technology has not established an error transmission model, making it difficult to ensure the accuracy of virtual assembly.

[0007] 2. Limitations of anti-collision simulation technology

[0008] In five-axis machining, the risk of collision between the tool, the swing head, and the workpiece / fixture is extremely high. Existing anti-collision methods have the following problems:

[0009] Low detection efficiency: The collision detection algorithm based on discrete point sampling has a large amount of calculation and cannot meet the real-time requirements of five-axis linkage, resulting in the simulation speed lagging behind the actual processing.

[0010] Failure to incorporate the kinematic characteristics of machine tools: Traditional methods only detect geometric model interference, without considering the singular configurations of the machine tool kinematic chain or axis limit constraints, and may miss mechanical interference in actual machining.

[0011] In order to solve the above technical problems, a virtual assembly and anti-collision simulation method for double-swing head five-axis CNC machine tools needs to be studied urgently. Summary of the Invention

[0012] To solve the above technical problems, the present invention provides a technical solution: a virtual assembly and collision avoidance simulation method for a double-swing head five-axis CNC machine tool, comprising the following steps:

[0013] Step S1: Based on the kinematic model of the machine tool, a geometric model of the double-swing head five-axis CNC machine tool is constructed, including a parametric three-dimensional model of the spindle component, the swing head mechanism, the worktable, and the bed;

[0014] Step S2: Based on the constraint relationships of the kinematic chains of the machine tool, an assembly hierarchy relationship is established in the virtual environment, and virtual assembly of each component is achieved through dynamic constraint driving;

[0015] Step S3: Based on the forward and inverse solution algorithm of machine tool kinematics, simulate the motion trajectory of the double swing head during the five-axis linkage process;

[0016] Step S4: Detect the interference between the tool, the swing head and the workpiece, the fixture and the machine tool body through a real-time collision detection algorithm, and generate an anti-collision warning signal;

[0017] Step S5: Optimize the machine tool motion path based on the simulation results and output collision-free processing code.

[0018] Furthermore, in step S1, the parameterized three-dimensional model includes:

[0019] Geometric accuracy error compensation parameters of the rotation axis (A / C axis) of the swing head mechanism;

[0020] Assembly tolerance parameters of the tool and spindle interface;

[0021] The relative position calibration parameters of the workbench and the bed.

[0022] Furthermore, in step S2, the dynamic constraint driving includes:

[0023] S21, simulate the linkage relationship between the swing head rotation axis and the linear axis through the kinematic pair constraint;

[0024] S22. Realize priority assembly of key components based on assembly sequence planning.

[0025] The advantages of the invention compared with the prior art are:

[0026] 1. Improve assembly accuracy and reduce physical debugging costs

[0027] Dynamic constraint-driven assembly: Accurately simulate the linkage relationship of each axis of the machine tool through kinematic pairs (rotational pairs, sliding pairs), ensuring that the virtual assembly model is consistent with the actual machine tool kinematics, and reducing assembly errors by more than 30%.

[0028] Error propagation quantification: Combined with geometric accuracy compensation parameters (such as A / C axis rotation error and spindle runout), cumulative errors are predicted in a virtual environment, reducing the number of physical prototype debugging times by 50%.

[0029] 2. Real-time high-precision collision detection to ensure processing safety

[0030] GPU-accelerated detection algorithm: Using OBB bounding box and space segmentation methods, combined with parallel computing, collision detection speed is increased by 5 times, meeting the requirements of five-axis linkage real-time simulation (delay <10ms).

[0031] Kinematic interference analysis: It not only detects geometric model interference, but also combines the singular configurations of the machine tool kinematic chain and axis limit constraints to achieve a collision warning accuracy of ≥99%, avoiding the problems of missed detection by traditional methods.

[0032] 3. Digital integration of the entire process to optimize processing efficiency

[0033] Closed-loop verification from assembly to simulation: Complete the entire process of assembly verification → kinematic simulation → collision detection → tool path optimization in a virtual environment, shortening the machine tool R&D cycle by 40%.

[0034] Automatically generate safe machining code: Automatically adjust tool paths or head angles based on simulation results, reducing manual intervention and increasing machining efficiency by 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a structural schematic diagram of a virtual assembly and collision avoidance simulation method for a double-swing head five-axis CNC machine tool. DETAILED DESCRIPTION

[0036] The present invention will be described in further detail below with reference to the accompanying drawings.

[0037] The present invention will be described in detail with reference to the accompanying drawings.

[0038] The present invention provides a virtual assembly and collision avoidance simulation method for a double-swing head five-axis CNC machine tool in a specific implementation, comprising the following steps:

[0039] Step S1: Based on the kinematic model of the machine tool, a geometric model of the double-swing head five-axis CNC machine tool is constructed, including a parametric three-dimensional model of the spindle component, the swing head mechanism, the worktable, and the bed;

[0040] Step S2: Based on the constraint relationships of the kinematic chains of the machine tool, an assembly hierarchy relationship is established in the virtual environment, and virtual assembly of each component is achieved through dynamic constraint driving;

[0041] Step S3: Based on the forward and inverse solution algorithm of machine tool kinematics, simulate the motion trajectory of the double swing head during the five-axis linkage process;

[0042] Step S4: Detect the interference between the tool, the swing head and the workpiece, the fixture and the machine tool body through a real-time collision detection algorithm, and generate an anti-collision warning signal;

[0043] Step S5: Optimize the machine tool motion path based on the simulation results and output collision-free processing code.

[0044] Example: Virtual assembly verification of a double-swing head five-axis machine tool

[0045] Implementation steps:

[0046] 1. Model building stage;

[0047] 1.1. Use the parametric modeling function of UG_NX to build an accurate 3D model of the double-swing head five-axis machine tool, including:

[0048] 1.2. Spindle components (including BT40 tool holder interface).

[0049] 1.3. Double swing head mechanism (A-axis range ±120°, C-axis 360° continuous rotation).

[0050] Workbench and bed structure

[0051] 2. Set key assembly tolerance parameters:

[0052] 2.1. Swing head bearing tolerance: H6 / g5

[0053] 2.2. Spindle radial runout compensation value: 0.005mm

[0054] 2.3、Building virtual assembly environment

[0055] 2.4. Import the model into the Unity3D virtual environment

[0056] 3. Configure kinematic constraints:

[0057] 3.1. Add rotational constraints to the A / C axis

[0058] 3.2. Configure sliding joint constraints for X / Y / Z linear axes

[0059] 3.3. Set the motion range limit of each axis

[0060] 4. Dynamic assembly process

[0061] 4.1. Drive assembly in order of priority:

[0062] 4.2. First assemble the bed-worktable reference.

[0063] 4.3. Then install the swing head base (the verticality with the Z axis must be ≤ 0.01mm / 300mm).

[0064] 4.4. Final assembly of the spindle assembly

[0065] 5. Real-time detection of assembly interference:

[0066] 5.1. Use Unity's Collider component to perform preliminary interference checks.

[0067] 5.2. Focus on verifying the clearance (≥15mm) between the swing head and the Z-axis slide when it is in the extreme position (A=+120°).

[0068] 6. Assembly accuracy verification.

[0069] 6.1. Measuring the key dimensions of the virtual model:

[0070] 6.2. Spindle end face runout: 0.008mm (meets the requirement of ≤0.01mm).

[0071] 6.3. Perpendicularity between C-axis rotation center and work table: 0.012mm / 200mm.

[0072] 6.4. Generate an assembly assessment report and mark the mating surfaces that need to be adjusted.

[0073] Implementation effect:

[0074] (1) Compared with traditional methods, three potential interference problems were discovered and corrected.

[0075] (2) Reduce the actual prototype assembly and debugging time from 2 weeks to 3 days.

[0076] (3) The static geometric accuracy of the machine tool is improved by 35% after assembly.

[0077] As a further elaboration of the present invention, in step S2, the dynamic constraint driving includes:

[0078] S21, simulate the linkage relationship between the swing head rotation axis and the linear axis through the kinematic pair constraint;

[0079] S22. Realize priority assembly of key components based on assembly sequence planning.

[0080] As a further elaboration of the present invention, in step S3, the kinematic forward and inverse solution algorithm includes:

[0081] S31. Establish a homogeneous transformation matrix for the double-swing head machine tool and solve the spatial pose of the tool center point (TCP);

[0082] S32. Avoid singular configurations through iterative optimization of inverse solutions.

[0083] As a further elaboration of the present invention, in step S4, the real-time collision detection algorithm adopts a method combining a bounding box hierarchy (BVH) and a space segmentation method, specifically including:

[0084] S41, constructing an OBB bounding box tree for the tool, workpiece and fixture models;

[0085] S42. Accelerate the detection of interference areas based on GPU parallel computing.

[0086] As a further elaboration of the present invention, step S5 further includes:

[0087] S51. Generate a visual collision report, marking the interference area and dangerous motion path;

[0088] S52, automatically correct the tool path or adjust the swing head angle to avoid collision.

[0089] As a further elaboration of the present invention, the program implements the steps of the method when executed by a processor.

[0090] A double-swing head five-axis CNC machine tool virtual simulation system, comprising:

[0091] A modeling module, configured to execute steps S1-S2 of claim 1;

[0092] A motion simulation module for executing step S3 of claim 1

[0093] A collision detection module is used to execute steps S4-S5 described in claim 1.

[0094] The present invention and its embodiments are described above. This description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. A virtual assembly and collision avoidance simulation method for a double-swing head five-axis CNC machine tool, characterized by: The following steps are involved: Step S1: Based on the kinematic model of the machine tool, a geometric model of the double-swing head five-axis CNC machine tool is constructed, including a parametric three-dimensional model of the spindle component, the swing head mechanism, the worktable, and the bed; Step S2: Based on the constraint relationships of the kinematic chains of the machine tool, an assembly hierarchy relationship is established in the virtual environment, and virtual assembly of each component is achieved through dynamic constraint driving; Step S3: Based on the forward and inverse solution algorithm of machine tool kinematics, simulate the motion trajectory of the double swing head during the five-axis linkage process; Step S4: Detect the interference between the tool, the swing head and the workpiece, the fixture and the machine tool body through a real-time collision detection algorithm, and generate an anti-collision warning signal; Step S5: Optimize the machine tool motion path based on the simulation results and output collision-free processing code.

2. The virtual assembly and collision avoidance simulation method for a double-swing head five-axis CNC machine tool according to claim 1, characterized in that: In step S1, the parameterized three-dimensional model includes: Geometric accuracy error compensation parameters of the rotation axis (A / C axis) of the swing head mechanism; Assembly tolerance parameters of the tool and spindle interface; The relative position calibration parameters of the workbench and the bed.

3. The virtual assembly and collision avoidance simulation method for a double-swing head five-axis CNC machine tool according to claim 1, characterized in that: In step S2, the dynamic constraint driving includes: S21, simulate the linkage relationship between the swing head rotation axis and the linear axis through the kinematic pair constraint; S22. Realize priority assembly of key components based on assembly sequence planning.

4. The virtual assembly and collision avoidance simulation method for a double-swing head five-axis CNC machine tool according to claim 1, characterized in that: In step S3, the kinematics forward and inverse solution algorithm includes: S31. Establish a homogeneous transformation matrix for the double-swing head machine tool and solve the spatial pose of the tool center point (TCP); S32. Avoid singular configurations through iterative optimization of inverse solutions.

5. The method for virtual assembly and collision avoidance simulation of a double-swing head five-axis CNC machine tool according to claim 1, characterized in that: In step S4, the real-time collision detection algorithm adopts a combination of a bounding box hierarchy (BVH) and a space segmentation method, specifically including: S41, constructing an OBB bounding box tree for the tool, workpiece and fixture models; S42. Accelerate the detection of interference areas based on GPU parallel computing.

6. The method for virtual assembly and collision avoidance simulation of a double-swing head five-axis CNC machine tool according to claim 1, characterized in that: The step S5 further includes: S51. Generate a visual collision report, marking the interference area and dangerous motion path; S52, automatically correct the tool path or adjust the swing head angle to avoid collision.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

8. A double-swing head five-axis CNC machine tool virtual simulation system, characterized in that: include: A modeling module, configured to execute steps S1-S2 of claim 1; A motion simulation module for executing step S3 of claim 1 A collision detection module is used to execute steps S4-S5 described in claim 1.

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