17 results about "Geometric error" patented technology

The application discloses a numerical control machine tool precision distribution method from geometric error to manufacturing tolerance, comprising: using small deformation hypothesis and superposition principle to obtain the influence coefficient matrix of manufacturing tolerance to position related geometric error, and combining with the machine tool motion chain to establish a manufacturing tolerance-geometric error-space error three-layer mapping model; adopting Sobol total effect sensitivity analysis of the overall workspace characteristic trajectory to obtain the total effect sensitivity index of each manufacturing tolerance; establishing a manufacturing cost evaluation model, and combining with the total effect sensitivity index to construct a cost sensitivity index; taking the minimum manufacturing cost as the target, comprehensively considering the tolerance definition domain constraint, the sorting constraint and the space error confidence constraint, and using an optimization algorithm to realize precision distribution. The application traces the precision distribution from the abstract geometric error level to the part manufacturing tolerance level, and can further realize the collaborative optimization of machine tool precision design and manufacturing cost.

This invention provides a method for sensitive identification and iterative compensation of geometric errors in gear tooth profile. Specifically, it includes the following steps: Step 1: Measuring the geometric errors of each axis of the machine tool using a laser interferometer, and establishing a geometric error-tooth profile error coupling model based on the principles of homogeneous coordinate transformation and form grinding; Step 2: Introducing Sobol global sensitivity analysis and quasi-Monte Carlo sampling to analyze the errors and screen out the key geometric error terms that have the greatest impact on tooth profile error; Step 3: Constructing an iterative compensation model based on sensitivity matrix and step size coefficient control with the goal of minimizing tooth profile error, and obtaining the compensation amount through iterative calculation. This invention combines sensitivity analysis with iterative solution, more effectively solving the compensation problem under nonlinear strong coupling conditions. Furthermore, this invention only compensates for key geometric errors, reducing the interference of redundant variables, lowering the computational load, and improving gear grinding accuracy.

This invention belongs to the field of CNC machining technology and discloses a method and apparatus for avoiding singular points in five-axis machining tool trajectories based on Riemann optimization. The method includes S1: reading tool position data and identifying singular regions in the machining path; S2: establishing an objective function on a unit spherical manifold, the objective function being used to guide the tool axis direction to deviate from the singular regions in step S1; S3: iteratively solving the objective function in step S2 using the Riemann optimization method to obtain the optimized tool axis direction to avoid the singular regions, reconstructing the trajectory of the optimized tool axis direction, and outputting the final tool position point through nonlinear error control. This invention avoids projection errors by directly optimizing the tool direction on a unit spherical manifold, uniformly handling the requirements of trajectory smoothness, accuracy, and non-singularity, effectively controlling geometric errors while ensuring machining continuity, and significantly improving the quality and reliability of five-axis CNC machining.

This invention relates to the fields of intelligent manufacturing and computer-aided inspection technology, and particularly to a system for constructing and reasoning a knowledge base for precision machining geometric error inspection operators. The system includes a feature parsing module, used to read a 3D solid model containing product geometric technical specifications, extract geometric surface features and associated tolerance specifications from the model, wherein the tolerance specifications include tolerance thresholds, and convert the geometric surface features and tolerance specifications into semantic ontology instances, outputting a set of element instances. In this invention, by automatically parsing the geometric features and geometric tolerance semantics in the 3D solid model, and combining this with actual point cloud data obtained from on-machine measurement for error assessment and reverse calculation of compensation parameters, a closed-loop mapping from design tolerance semantics to CNC system compensation instructions is achieved. This enables the machining equipment to automatically correct the tool position and coordinate system offset based on actual inspection results, thereby improving the machining accuracy and consistency of parts.

This invention discloses a multi-level mapping method for characterizing machine tool accuracy degradation and optimizing its key parameters, belonging to the field of machine tool accuracy retention technology. This method constructs a complete technical framework of forward modeling and prediction followed by reverse parameter optimization, achieving quantitative prediction and proactive control of machine tool accuracy retention throughout its entire lifecycle through four-level mapping. First, based on the small displacement screw method and multibody system theory, a whole-machine spatial accuracy model considering geometric errors at large assembly interfaces is constructed. Second, combining numerical simulation, the Arcard wear model, and the superposition method, a time-varying degradation model of guideway straightness under multi-physics coupling is established. Third, by integrating the straightness and perpendicularity degradation laws, a time-varying equation for whole-machine spatial accuracy is derived, clarifying the mapping relationship of multi-level time-varying factors. Finally, using the accuracy degradation rate as an evaluation index, the machining and assembly process parameters are optimized through reverse derivation, forming a closed-loop optimization system. This invention is of great significance for improving the accuracy retention of high-end CNC machine tools.

This application relates to the field of machine tool precision design technology, and particularly to a precision design method, apparatus, electronic device, and storage medium for hybrid machine tools. The method includes: acquiring the structural parameters of the hybrid machine tool; determining the vector loop equation of the hybrid machine tool; determining the mapping relationship between the geometric error and the end effector error of the hybrid machine tool based on the vector loop equation; thereby determining the sensitivity index and identifiability index of the hybrid machine tool; and screening target geometric errors that meet preset screening conditions to generate the precision design result of the hybrid machine tool based on the target geometric errors. This solves the problem in related technologies where the identifiability of geometric error terms in subsequent calibration processes is not considered, leading to difficulties in effectively compensating for geometric error terms through tolerance values ​​when the geometric error terms cannot be identified.

The application relates to a geometric model repairing method, device, equipment and program product, and relates to the technical field of computers. The method comprises the following steps: acquiring an error region image of a target geometric error in a model to be repaired and error description information of the target geometric error; determining an error repairing strategy matched with the target geometric error according to the error region image and the error description information; and repairing the target geometric error according to the error repairing strategy. The method can accurately determine the error repairing strategy matched with the target geometric error, and improves the success rate of repairing the target geometric error.

This invention discloses a method for analyzing the geometric error of gearbox housings based on thermo-structural coupling deformation, belonging to the technical field of mechanical transmission systems. Addressing the problem of decreased geometric accuracy of automotive gearbox housings under complex operating conditions due to thermo-mechanical coupling, this invention establishes a thermo-mechanical coupling model of the bearing bores, reveals the nonlinear deformation law under the combined action of temperature field and mechanical load, constructs a geometric accuracy evaluation system with parallelism and center distance errors as the core, and combines finite element simulation to quantitatively analyze the housing deformation. This invention provides a feasible analytical method for structural optimization and precision control of gearbox housings, effectively improving gear meshing accuracy and transmission system reliability.

This invention discloses a method for planning the grinding trajectory of variable-parameter chip grooves considering kinematic smoothness, comprising the following steps: parametric geometric model; establishing a model of equivalent machining error for groove width and equivalent machining error for core thickness based on the principle of circular arc envelope projection; establishing a smoothness measurement index model based on the composite smoothness principle of grinding wheel posture geometric continuity and machine tool kinematic performance; constructing a multi-objective trajectory planning model with geometric error, posture smoothness error, and machine tool kinematic performance error as objectives; constructing the planning model as a multi-objective optimization problem that dynamically evolves along the axial section, and solving it according to the principle of dynamic optimization to obtain the Pareto optimal solution set of continuous grinding wheel posture; performing five-axis post-processing on the optimal grinding wheel posture sequence to generate a machine tool trajectory and CNC program that satisfy machining constraints. This invention can significantly improve the machining accuracy, posture smoothness, and machine tool motion stability during the chip groove grinding process of variable-parameter milling cutters.

This invention discloses a dynamic compensation method for pitch and perpendicularity errors in CNC machine tools, comprising the following steps: constructing and updating the comprehensive state vector of the machine tool in real time; extracting a set of time-varying geometric error parameters with clear physical meaning from the state vector in real time, the set of time-varying geometric error parameters including a transient pitch error table based on dynamic estimation of axis position, temperature and load force, and a dynamic perpendicularity angle change based on dynamic identification of structural temperature difference and off-center load moment; calculating the multi-axis synchronous correction command position required to offset the current error; generating a multi-axis linkage micro-compensation command vector that is strictly synchronized with the original command cycle by subtracting the correction command position from the original interpolation command; injecting the micro-compensation command vector into the command end of the CNC system position loop through command feedforward superposition, or acting on the system coordinate transformation layer by writing it into a high-speed dynamic coordinate offset.

Numerical control device for a machine tool, wherein the numerical control device controls a machine tool having a main spindle (2) for mounting a tool, a table (3) holding a workpiece and a clamping device, three translational axes and one or more rotational axes, wherein the numerical control device comprises: a fault determination unit (19) which measures a position of a target mounted on any of the main spindle (2) and the table (3) using a measuring unit mounted on another of the main spindle (2) and the table (3) and determines an axis-dependent deformation fault parameter based on three-dimensional coordinate values ​​of a plurality of the measured positions of the target, an axis-dependent deformation error estimation unit (20) which calculates an estimated value of an axis-dependent deformation error caused by a deformation of the machine tool due to an operation of at least one of the translation axes and the rotation axes based on at least the axis-dependent deformation error parameter and a function of a geometric error of six degrees of freedom of the rotation axes, taking the instruction value of the rotation axes; an input unit (17) that receives a mass and a center of gravity position from at least one of the workpiece and the clamping device; a gravitational deformation estimation unit (18) which calculates an estimated value of a gravitational deformation error caused by the mass of at least one of the workpiece and the clamping device based on a function depending on at least one gravitational deformation error parameter, the mass and the center of gravity position received at the input unit (17) and the instruction values ​​of the rotation axes; a correction value calculation unit (16) that calculates correction values ​​for at least one of the translational and rotational axes with respect to an error in the position and orientation of the tool with respect to the workpiece, based on the estimated value of the axis-dependent deformation error, the estimated value of the gravitational deformation error, and the instruction values; and an addition unit (21) that adds the correction values ​​to the instruction values.

This invention discloses a method for identifying the geometric error of the B-axis in a five-axis swivel-head CNC machine tool, belonging to the field of CNC machine tool accuracy testing and error compensation technology. The method first establishes a B-axis body coordinate system model, measuring position-independent perpendicularity and angular positioning errors as known parameters. Then, it sequentially executes four measurement modes: B-X, B-Z, B-Y, and B-XY, obtaining the equations for the change in rod length of the ballbar in each direction. By solving the simultaneous equations, it sequentially solves for the three runout errors and three angular errors of the B-axis, completing the identification of all six position-related geometric errors. This invention has advantages such as comprehensive error identification, high measurement efficiency, high identification accuracy, small systematic deviation, adjustable parameters, and strong engineering applicability, and is suitable for the rapid and accurate identification of B-axis geometric errors in various types of five-axis swivel-head CNC machine tools.

The present application provides a method and apparatus for acquiring geometric error of a rotating shaft. The method for acquiring geometric error includes the following steps. A ring encoder is installed on the rotating shaft, and a first optical reading head and a second optical reading head are installed around the ring encoder. The ring encoder is rotated by the rotating shaft, and a deviation distance and an azimuth angle of a center point of the ring encoder relative to a center axis of the rotating shaft when the rotating shaft rotates 0 degree are acquired according to an angle value read by the first optical reading head. A first assembly angle deviation of the first optical reading head and a second assembly angle deviation of the second optical reading head are acquired. A rotation angle error of the rotating shaft when rotating to each angle is acquired. A rotation runout error of the rotating shaft when rotating to each angle is acquired.

This invention belongs to the field of CNC machining technology, specifically relating to a tool adjustment method for a milling and turning machining center. The invention collects position and clearance data of the tool and spindle under both milling and turning states via a detection unit. After calculating basic parameters, it reverse-engineers the error matrix between the spindle and the chuck. Based on the error matrix, it generates compensation commands to drive the axis system and chuck in linkage adjustment. After closed-loop retesting and verification, the compensation parameters are stored after the error meets the standard. During machining, it monitors reading fluctuations in real time, and judges thermal deformation or load deformation errors based on the same or opposite fluctuation characteristics of the milling and turning readings, driving the axis system for micro-motion correction. This invention constructs an error matrix reverse-engineering and dynamic compensation mechanism, eliminating reliance on operator experience, shortening machine tool occupancy time, and ensuring consistency in milling and turning state adjustments. It effectively compensates for dynamic deviations caused by thermal deformation and geometric errors, suppresses machining accuracy drift, and improves machining stability and yield.

A method for tracing the source of key geometric errors in a five-axis CNC milling machine belongs to the field of machine tool accuracy analysis technology. Specifically, it involves a spatial motion error modeling method for multi-axis CNC machine tools based on multibody system theory, a machine tool machining accuracy prediction method based on the side-cut milling principle, and a key geometric error tracing and analysis method. This invention establishes a spatial motion error model, a machining accuracy prediction model, and a key geometric error tracing and analysis model for multi-axis CNC machine tools. By tracing and analyzing the source of key geometric errors in multi-axis CNC machine tools during the machine tool accuracy optimization design phase, machine tool design engineers can accurately identify key geometric errors. This helps to obtain the influence weight of various geometric errors on machine tool machining accuracy before machine tool accuracy optimization design, correctly guiding machine tool accuracy design and laying a theoretical foundation for CNC machine tool accuracy optimization design.

This invention relates to the field of CNC machine tool technology, specifically to a method for fusing and decoupling spatial geometric errors in multi-axis CNC machine tools. The method includes the following steps: Step 1. Dividing the measurement space into a spatial cube and calibrating the geometric errors of the cubic measurement space; Step 2. Using an IMU and a laser interferometer to fuse the spatial errors along each axis; Step 3. Using a nonlinear error identification curve for error estimation; Step 4. Using dual IMUs to predict the CNC machine tool errors; Step 5. Establishing a corresponding mathematical model and using dual IMUs to decouple the spatial geometric errors of the CNC machine tool. By fusing the errors measured by the laser interferometer and the IMU, the error measurement becomes more accurate, laying a solid foundation for subsequent error prediction and decoupling.

The application relates to a detection device and a detection method for the geometric error of a rotating shaft of an RTTTR type machine tool, the detection device comprising a base, an X-direction sliding table, a Y-direction sliding table, a Z-direction sliding table, a rotary table and three grating scales; the grating scales are respectively installed on the Z-direction sliding table, the X-direction sliding table and the Y-direction sliding table, the axes of the grating scales intersect with the axes of the Z-direction sliding table, the X-direction sliding table and the Y-direction sliding table in space and are perpendicular to each other; the axes of the grating scales are respectively parallel to the displacement directions of X-direction sliding rails, Y-direction sliding rails and Z-direction sliding rails of the machine tool; reading heads of the grating scales are respectively installed on the X-direction sliding table, the Y-direction sliding table and the Z-direction sliding table; the Z-direction sliding table, the X-direction sliding table and the Y-direction sliding table respectively measure the spatial position coordinates of displacement of a workpiece ball of a ball bar along the Z-axis, the X-axis and the Y-axis directions, and are used for calculating the geometric error of a B-axis rotating shaft of the machine tool; the technical scheme has higher measurement precision and meets the requirement of rapid measurement.