A cam-based milling path correction method

Abstract

The application relates to the technical field of numerical control machining instruction control flow optimization, and discloses a milling path correction method based on CAM, which comprises the following steps: analyzing original numerical control instruction flow to obtain a nominal coordinate sequence, determining a spatial curvature variation amount through a trajectory curvature calculation model, calculating a tool displacement deviation biasing amount according to machine tool axial kinematics constraints and structural stiffness characteristics, multiplying the tool displacement deviation biasing amount by a wear compensation correction coefficient to correct, calculating a path correction vector through hierarchical adaptive control branch to generate a correction coordinate sequence, calculating the normal shortest distance between the correction coordinate sequence and a model grid surface through an overcut interference checking logic to implement safety limiting and cutting control, and outputting a corrected numerical control instruction flow. Before the control instruction output front end, the application implements reverse offsetting on a dynamic cutting deformation variable, eliminates physical trajectory lag in variable-curvature machining, and improves the geometric following fidelity of digital path instructions.

Description

Technical Field

[0001] This invention belongs to the field of CNC machining instruction control flow optimization technology, and particularly relates to a CAM-based milling path correction method. Background Technology

[0002] Current computer-aided manufacturing systems require the generation of multi-dimensional toolpath trajectories for precision parts in their digital control processes. Common technical solutions utilize spatial discrete sampling point sequences to fit nominal geometric CNC commands and calculate nominal machining coordinates based on standard spatial topological relationships. While these conventional path planning methods can construct toolpath sequences with regular geometric configurations and establish the foundation for digital trajectory generation, the continuous abrupt changes in spatial geometric features during the precision machining of complex variable curvature surface parts lead to high data dispersion in the machining command sequence. When a multi-axis CNC system runs this machining command sequence, the drive mechanism needs to frequently change the feed motion state, causing nonlinear fluctuations in the transient cutting force at the contact point between the tool system and the part surface, resulting in temporal degradation of cutting stiffness. Traditional path correction methods rely solely on superimposing static offset vectors onto nominal model data, neglecting the dynamic causal response relationship between spatial curvature changes and transient stress deformation. This causes data deformation within the discrete command control flow, and this displacement distortion is directly transmitted to subsequent servo actuators, resulting in contour lag and elastic avoidance deformation at the machining site.

[0003] Some solutions attempt to suppress the aforementioned deformation by adjusting the roller shape and transmission component structure to improve the hardware stiffness of the internal linkage mechanism. However, this leads to an increase in physical structural complexity and manufacturing costs, making trajectory pre-compensation at the command front end through software control methods an inevitable choice. Existing control and post-processing methods also face the bottleneck of insufficient dynamic adaptive capabilities. For example, Chinese invention patent CN110737245B discloses a post-processing method and system for dual five-axis mirror milling. The solution relies on static machine tool configuration files and nominal trajectories to perform rigid geometric coordinate transformation. This offline multi-level mapping based solely on the assumption of an ideal rigid body completely mismatches dynamic non-ideal working conditions such as nonlinear fluctuations in cutting force and temporal wear of physical cutting edges in the machining of complex variable curvature surfaces. Due to the lack of numerical closed-loop control that depends on both geometric features and temporal step size, the reconstructed control code cannot actively eliminate the nonlinear dynamic losses of the linkage mechanism. It is very easy to cause data reconstruction cycle numerical divergence at the boundary of sudden curvature changes. Furthermore, due to the lack of dynamic interference arbitration of hard topological boundaries, there is a risk of tool cutting interference and fundamental deviations in the surface of the parts when over-compensating.

[0004] Therefore, how to construct a data closed-loop processing flow with adaptive timing adjustment and hard topological boundary constraints, realize the active adjustment of abrupt curvature difference signals in the data space, and coordinate the fidelity of the machining trajectory with the efficiency of CNC interpolation calculation, has become the technical problem to be solved by this invention. Summary of the Invention

[0005] The present invention aims to solve the problem of how to construct a data closed-loop processing flow with adaptive timing adjustment and hard topological boundary constraints in order to coordinate the fidelity of machining trajectory and the timeliness of CNC interpolation calculation.

[0006] In this technical solution, a CAM-based milling path correction method includes the following steps:

[0007] Step S101: Parse the original CNC instruction stream to obtain the nominal coordinate sequence and nominal machining speed;

[0008] Step S102: The distance between two adjacent points in the nominal coordinate sequence is calculated by differential calculation using the trajectory curvature calculation model to determine the spatial curvature variation.

[0009] Step S103: Based on the machine tool axial kinematic constraints and structural stiffness characteristics, the tool displacement deviation offset is calculated simultaneously, and the total amount of processed stroke is continuously accumulated through the processing stroke accumulation logic. When the total stroke exceeds the life stroke threshold, the tool displacement deviation offset is nonlinearly increased and corrected using the wear compensation correction coefficient.

[0010] Step S104: Through hierarchical adaptive control branches, the path correction vector is calculated based on the spatial curvature variation and the corrected tool displacement deviation offset, and the nominal coordinate sequence is reconstructed to generate the correction coordinate sequence. The shortest normal distance between the correction coordinate sequence and the model mesh surface is calculated through overcutting interference verification logic. When the shortest normal distance indicates that the correction coordinate sequence has invaded the interior of the material entity and the absolute value is greater than 0.01mm, the safety limit truncation control logic is activated and the dynamic gain in the path correction vector is stripped off. The correction coordinate sequence is truncated to the 0.005mm tolerance zone boundary, and the corrected CNC command flow is output.

[0011] Preferably, step S104 includes the following steps through hierarchical adaptive control branch: Step S1041, when the tool displacement deviation offset does not cross the first deviation threshold, the path correction vector is kept at 0mm; Step S1042, when the tool displacement deviation offset is between the first deviation threshold and the second deviation threshold and the nominal machining speed exceeds the speed threshold, the path correction vector is linearly increased as the tool displacement deviation offset increases; Step S1043, when the tool displacement deviation offset crosses the second deviation threshold, the path correction vector is truncated and locked to 0.080mm.

[0012] Preferably, step S102, which calculates the distance between two adjacent points in the nominal coordinate sequence using the trajectory curvature calculation model to determine the spatial curvature variation, includes the following steps: Step S1021, extracting three consecutive adjacent nominal coordinate points from the nominal coordinate sequence to construct a preceding chord vector and a following chord vector; Step S1022, calculating the angle variation between the preceding chord vector and the following chord vector and the chord length proportionality coefficient; Step S1023, calculating the local curvature value at each nominal coordinate point based on the angle variation and the chord length proportionality coefficient, and solving the rate of change of the local curvature value between adjacent nominal coordinate points using a second-order difference algorithm, as the spatial curvature variation.

[0013] Preferably, the method includes the following steps: Step S105, after generating the nominal coordinate sequence in step S101 and before using the nominal coordinate sequence in step S102, calculate the Euclidean distance between adjacent nominal coordinate points in the nominal coordinate sequence. When the Euclidean distance is less than 0.001 mm, the current nominal coordinate point is determined to be a coincident redundant point and is removed.

[0014] Preferably, step S104, which calculates the shortest normal distance between the corrected coordinate sequence and the model mesh surface through overcutting interference verification logic, includes the following steps: Step S1044, importing the three-dimensional topological mesh data corresponding to the model mesh surface of the part; Step S1045, within a 10μs control window before outputting the corrected CNC command stream, using a signed distance function to traverse and calculate the coordinates of the nodes to be output in the corrected coordinate sequence; Step S1046, calculating the shortest spatial geometric distance between the coordinates of the nodes to be output and the model mesh surface, and using the sign of the normal vector of the shortest spatial geometric distance as the interference criterion. When the sign of the normal vector points to the interior of the part entity, the shortest spatial geometric distance is determined as the shortest normal distance.

[0015] Preferably, step S104, which truncates the corrected coordinate sequence to within the 0.005mm tolerance zone boundary, includes the following steps: Step S1047, when the safety limiting truncation control logic is activated, extract the local machining normal vector at the coordinates of the node to be output; Step S1048, obtain the maximum allowable tolerance value of 0.005mm, and apply an axial offset to the coordinates of the node to be output along the opposite direction of the local machining normal vector, locking the offset coordinates within the tolerance zone boundary.

[0016] Preferably, the calculation of the path correction vector in step S104 further includes the following steps: Step S1049, calculate the absolute value of the spatial curvature variation in real time, and when the absolute value increases monotonically, reduce the nominal processing speed of the corresponding processing node and simultaneously increase the gain control parameter in the hierarchical adaptive control branch.

[0017] Preferably, step S103, which involves simultaneously calculating the tool displacement deviation offset based on the machine tool's axial kinematic constraints and structural stiffness characteristics, includes the following steps: Step S1031, obtaining the real-time geometric motion transfer matrix of each rotary axis and linear axis of the CNC machine tool; Step S1032, projecting the displacement components between adjacent nominal coordinate points onto each motion axis, calculating the servo hysteresis deviation of each linear axis under dynamic reversal conditions, and superimposing the servo hysteresis deviation into the tool displacement deviation offset.

[0018] Preferably, the method includes the following steps: Step S106, after the modified CNC instruction stream is output in step S104, the modified CNC instruction stream is imported into the machine tool post-processing module, converted into a machining code file that conforms to the CNC system reading specification, and sent to the control bus of the CNC system.

[0019] Compared with existing technologies, the CAM-based milling path correction method of the present invention has the following advantages:

[0020] 1. In the milling path correction of CAM, the path parsing unit discretely samples the position vector of the nominal machining trajectory, the geometric space topology analysis operator calculates the local geometric curvature and unit normal vector at the current machining node, the forward temporal difference processor solves the curvature change rate of adjacent machining nodes, and when the amplitude of the spatial correction vector is greater than 0.050mm, the nominal temporal evolution step size of the next machining node is adjusted in the reverse direction to 1.5 times the original nominal value. This step size parameter is used as the denominator term input into the difference operation formula, and the curvature change rate of subsequent machining nodes adaptively converges to the smooth interval. This data flow closed-loop constraint mechanism eliminates the numerical divergence defect of the interpolation loop at the sharp corner transition code.

[0021] 2. The control logic unit intercepts the rate of curvature change and the nominal feed rate value. It uses a breakpoint-based three-layer cascaded state machine to determine the dynamic physical deviation factor. When the absolute value of the rate of change is within the first threshold, the deviation factor is locked as an offset. When it is between the first and second thresholds and the speed is too high, linear following adjustment is activated. When it exceeds the second threshold, a hard safety limit is triggered and locked to the maximum value. This adaptive hierarchical decision network deconstructs nonlinear stiffness deformation into deterministic control flow, avoiding the black box divergence caused by traditional table lookup and polynomial fitting, locking the displacement offset limit at high-frequency distortion, and maintaining the computational convergence efficiency of code reconstruction.

[0022] 3. The life decay integral operator continuously accumulates the total amount of machining stroke. When the total amount of stroke crosses the preset fatigue cutoff point, the data bus calls the prior process data structure and performs product fusion of the dynamic physical deviation factor and the one-dimensional monotonically increasing correction coefficient calculated based on the empirical wear sensitivity constant. This counteracts the cutting force fluctuations caused by physical edge wear. This structured parameter evolution path transforms the temporal physical stiffness decay characteristics into gain fine-tuning weights within the control flow, establishing an active anti-disturbance response of the data operator to the physical entity's deterioration state. This avoids the trajectory local contour lag and complex workpiece machining surface accuracy deterioration defects caused by fixed parameters in long-term continuous cutting tasks. Attached Figure Description

[0023] Figure 1 This is a flowchart of the digital trajectory path correction process of the present invention;

[0024] Figure 2 This is the path correction adaptive control structure diagram of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0026] A CAM-based milling path correction method includes the following steps:

[0027] Step S101: Parse the original CNC instruction stream to obtain the nominal coordinate sequence and nominal machining speed;

[0028] Step S102: The distance between two adjacent points in the nominal coordinate sequence is calculated by differential calculation using the trajectory curvature calculation model to determine the spatial curvature variation.

[0029] Step S103: Based on the machine tool axial kinematic constraints and structural stiffness characteristics, the tool displacement deviation offset is calculated simultaneously, and the total amount of processed stroke is continuously accumulated through the processing stroke accumulation logic. When the total stroke exceeds the life stroke threshold, the tool displacement deviation offset is nonlinearly increased and corrected using the wear compensation correction coefficient.

[0030] Step S104: Through hierarchical adaptive control branches, the path correction vector is calculated based on the spatial curvature variation and the corrected tool displacement deviation offset, and the nominal coordinate sequence is reconstructed to generate the correction coordinate sequence. The shortest normal distance between the correction coordinate sequence and the model mesh surface is calculated through overcutting interference verification logic. When the shortest normal distance indicates that the correction coordinate sequence has invaded the interior of the material entity and the absolute value is greater than 0.01mm, the safety limit truncation control logic is activated and the dynamic gain in the path correction vector is stripped off. The correction coordinate sequence is truncated to the 0.005mm tolerance zone boundary, and the corrected CNC command flow is output.

[0031] Preferably, step S104 includes the following steps through hierarchical adaptive control branch: Step S1041, when the tool displacement deviation offset does not cross the first deviation threshold, the path correction vector is kept at 0mm; Step S1042, when the tool displacement deviation offset is between the first deviation threshold and the second deviation threshold and the nominal machining speed exceeds the speed threshold, the path correction vector is linearly increased as the tool displacement deviation offset increases; Step S1043, when the tool displacement deviation offset crosses the second deviation threshold, the path correction vector is truncated and locked to 0.080mm.

[0032] Preferably, step S102, which calculates the distance between two adjacent points in the nominal coordinate sequence using the trajectory curvature calculation model to determine the spatial curvature variation, includes the following steps: Step S1021, extracting three consecutive adjacent nominal coordinate points from the nominal coordinate sequence to construct a preceding chord vector and a following chord vector; Step S1022, calculating the angle variation between the preceding chord vector and the following chord vector and the chord length proportionality coefficient; Step S1023, calculating the local curvature value at each nominal coordinate point based on the angle variation and the chord length proportionality coefficient, and solving the rate of change of the local curvature value between adjacent nominal coordinate points using a second-order difference algorithm, as the spatial curvature variation.

[0033] Preferably, the method includes the following steps: Step S105, after generating the nominal coordinate sequence in step S101 and before using the nominal coordinate sequence in step S102, calculate the Euclidean distance between adjacent nominal coordinate points in the nominal coordinate sequence. When the Euclidean distance is less than 0.001 mm, the current nominal coordinate point is determined to be a coincident redundant point and is removed.

[0034] Preferably, step S104, which calculates the shortest normal distance between the corrected coordinate sequence and the model mesh surface through overcutting interference verification logic, includes the following steps: Step S1044, importing the three-dimensional topological mesh data corresponding to the model mesh surface of the part; Step S1045, within a 10μs control window before outputting the corrected CNC command stream, using a signed distance function to traverse and calculate the coordinates of the nodes to be output in the corrected coordinate sequence; Step S1046, calculating the shortest spatial geometric distance between the coordinates of the nodes to be output and the model mesh surface, and using the sign of the normal vector of the shortest spatial geometric distance as the interference criterion. When the sign of the normal vector points to the interior of the part entity, the shortest spatial geometric distance is determined as the shortest normal distance.

[0035] Preferably, step S104, which truncates the corrected coordinate sequence to within the 0.005mm tolerance zone boundary, includes the following steps: Step S1047, when the safety limiting truncation control logic is activated, extract the local machining normal vector at the coordinates of the node to be output; Step S1048, obtain the maximum allowable tolerance value of 0.005mm, and apply an axial offset to the coordinates of the node to be output along the opposite direction of the local machining normal vector, locking the offset coordinates within the tolerance zone boundary.

[0036] Preferably, the calculation of the path correction vector in step S104 further includes the following steps: Step S1049, calculate the absolute value of the spatial curvature variation in real time, and when the absolute value increases monotonically, reduce the nominal processing speed of the corresponding processing node and simultaneously increase the gain control parameter in the hierarchical adaptive control branch.

[0037] Preferably, step S103, which involves simultaneously calculating the tool displacement deviation offset based on the machine tool's axial kinematic constraints and structural stiffness characteristics, includes the following steps: Step S1031, obtaining the real-time geometric motion transfer matrix of each rotary axis and linear axis of the CNC machine tool; Step S1032, projecting the displacement components between adjacent nominal coordinate points onto each motion axis, calculating the servo hysteresis deviation of each linear axis under dynamic reversal conditions, and superimposing the servo hysteresis deviation into the tool displacement deviation offset.

[0038] Preferably, the method includes the following steps: Step S106, after the modified CNC instruction stream is output in step S104, the modified CNC instruction stream is imported into the machine tool post-processing module, converted into a machining code file that conforms to the CNC system reading specification, and sent to the control bus of the CNC system.

[0039] Example 1: In the CNC milling of precision components involving high-frequency variable curvature surfaces, narrow grooves, and multi-dimensional corners, the computer-aided manufacturing system (CADS) plans the milling path, linking multi-axis actuators to follow the spatial coordinates defined by the control code. When continuous commands drive the machine tool axis system through the aforementioned abrupt geometric regions, the linked actuators, constrained by physical inertia and servo response delays, exhibit high-frequency nonlinear acceleration and deceleration behavior. This frequent speed jumps disrupt the constant balance of the cutting layer thickness per tooth, causing nonlinear fluctuations in the transient cutting force at the contact point between the tool system and the workpiece surface, resulting in spatial elastic displacement and trajectory retreat. Since the CNC path construction method only includes spatial geometric parameters and lacks quantitative indicators to characterize the correlation between trajectory abrupt changes and mechanical dynamic response losses, the output original CNC command stream cannot pre-counteract the dynamic cutting deformation. The actual cutting trajectory of the machining system lags behind the nominal machining trajectory in terms of normal contour and spatial trajectory distortion, reducing the contour accuracy of the finished component surface and increasing the risk of local overcutting and scrapping of the part.

[0040] As a specific example of the aforementioned general technical solution under machining conditions, the data parsing module acquires a sliding window sequence of three-dimensional spatial tool position coordinates from the input data stream, sequentially extracts continuous nominal coordinate sequences, and obtains the nominal machining speed. This nominal coordinate sequence includes adjacent three-dimensional position vectors. , , The geometric space topology analysis operator calculates the current processing node based on the spatial increment relationship between adjacent position vectors. Local geometric curvature value at The unit normal vector of the trajectory's nominal direction The obtained curvature data stream is then imported into a forward timing difference processor. By performing first-order forward difference operations on the curvature values ​​of adjacent machining nodes, the curvature evolution gradient between adjacent tool positions is calculated, and the rate of curvature change, reflecting the dynamic variation characteristics of the shaft system, is extracted. The specific calculation formula is as follows: ,in, For the current processing node The rate of change of curvature at that point For the current processing node The local geometric curvature value at that point, This represents the local geometric curvature value at the previous processing node. The nominal timing evolution between two adjacent processing nodes is increased.

[0041] Control unit intercepts rate of curvature change With the nominal feed rate value Subsequently, to eliminate the risk of numerical divergence caused by continuous function fitting, the hierarchical control branch of the conditional control flow reconstruction mechanism is invoked to determine the dynamic physical deviation factor. This control branch uses a three-layer cascaded conditional decision architecture to deterministically reconstruct the control flow, using the calculated tool displacement deviation data as the direct input source to the state machine: In the first state, when the tool displacement deviation is intercepted and does not cross the first deviation threshold of 0.010mm, it is determined that the machining path is in a flat area, and the three-dimensional physical backoff correction vector of that node is directly cleared to zero and kept at 0mm in the control register; In the second state, when the tool displacement deviation is determined to be between the second deviation threshold of 0.010mm and 0.060mm, and the nominal machining speed read from the data bus in real time exceeds the preset speed threshold, a linear following mechanism is triggered, so that the dynamic physical deviation factor is linearly amplified by a fixed engineering proportional coefficient of 0.0015mm·s / m as the tool displacement deviation increases; In the third state, when the tool displacement deviation is determined to cross the second deviation threshold of 0.060mm, it is determined that the multi-axis linkage slide system is facing a limit reversal. Overload impact directly triggers hard-limit truncation control, locking the maximum displacement offset limit to 0.080 mm. Furthermore, during execution, the aforementioned hierarchical adaptive control branch uses the calculated tool displacement deviation as the direct control input for state machine transitions and compares it online in real-time with a preset deviation threshold matrix: when the tool displacement deviation does not exceed the first deviation threshold of 0.010 mm, the path correction vector remains at 0 mm; when the tool displacement deviation is between the second deviation threshold of 0.010 mm and 0.060 mm, and the nominal machining speed exceeds the preset speed threshold, the path correction vector increases linearly with the increase of the tool displacement deviation; when the tool displacement deviation exceeds the second deviation threshold of 0.060 mm, the system limits and truncates the path correction vector, hard-locking it to 0.080 mm. Thus, the deterministic hierarchical decision-making of the data control flow fully covers the control criterion boundary of this invention, and the data path reconstruction operator obtains the dynamic physical deviation factor. Then, based on the unit normal vector Synthetic 3D Physical Retreat Correction Vector Its algebraic linear expression is ,in, This is the 3D physical setback correction vector. For dynamic physical deviation factor, As a unit normal vector, the data bus directly transmits the 3D physical setback correction vector. Compared with the original position vector A data structure for rewriting control code in situ is adopted by summing same-dimensional tensors, reconstructing the tool position data stream, and outputting a new type of compensated machining coordinate with physical retraction pre-compensation features. ,in, For new types of machining coordinate correction, The original position vector, This is a 3D physical setback correction vector; to prevent numerical divergence at variable curvature corners, a new type of correction machining coordinate is reconstructed. Reverse injection serves as a termination constraint for the sliding window sampling process, when the calculated 3D physical backoff correction vector... When the amplitude exceeds the safety angle variation limit of 0.050mm, the system triggers a reverse interference mechanism and forcibly modifies the nominal timing evolution step size at the next processing node, setting this step size parameter... The value was adjusted from the original nominal value and amplified to 1.5 times the original step size, due to the step size parameter. As a denominator term participating in the differential operations of the aforementioned forward-sequential differential processor, this adjustment affects the subsequent rate of curvature change. The automatic convergence to a smooth interval, specifically, the aforementioned reverse fine-tuning that amplifies the nominal timing evolution step size in situ to 1.5 times, is based on the underlying physical mechanism of actively blunting the nonlinear dynamic overload of the multi-axis linkage system by widening the time domain scale. Since geometric curvature changes are an inherent spatial topological property of the machining path, when the control code drives the machine tool through a variable curvature corner region, the axis system will generate high-frequency acceleration and deceleration excitation in a very short time. This invention, by increasing the step size parameter in the denominator of the forward timing differential processor, substantially increases the dynamic transition time through this geometrically abrupt region at the digital control level, which is equivalent to actively reducing the dynamic transition time of each linkage axis of the machine tool servo drive system during the feedforward stage. The transient acceleration change rate on the time axis, without changing the nominal geometric trajectory of the part, actively eliminates mechanical stress fluctuations by adaptively extending the time scale, ensuring the numerical convergence of the interpolation control flow. When simultaneously solving for the tool displacement deviation offset based on the machine tool axial kinematic constraints and structural stiffness characteristics, the determination path for the dynamic estimation of the transient cutting force of each linear axial direction is to analyze the preceding and succeeding point sequences of the current machining node in the original CNC command flow to extract the nominal cutting step size and nominal feed rate. The three-dimensional topological mesh data of the part is called, and the spatial transient contact geometric solid model of the tool and workpiece is dynamically constructed using mesh Boolean intersection and subtraction operations. The current machining node is then extracted. The transient material removal volume, axial cutting depth, and radial cutting depth corresponding to each point are calculated. Based on the workpiece material properties, a pre-calibrated empirical cutting energy database is retrieved. The retrieved axial and radial cutting energies are multiplied by the feed rate, axial cutting depth, and radial cutting depth for each tooth, respectively, to obtain dynamic estimates of the transient axial cutting force for each straight line. Load data for subsequent calculation of structural elastic deformation avoidance displacement is output. The dynamic estimates of the transient axial cutting force for each straight line are divided by the measured static stiffness of the CNC machine tool spindle overhang at the corresponding axial direction (45.0 N / μm). The static structural elastic deformation avoidance displacement for each straight axial direction is calculated in-situ within the data storage area. Simultaneously, the total data is... The system directly retrieves the servo hysteresis deviation value of the linear axis under dynamic reversal conditions, calculated from the real-time geometric motion transfer matrix of each linear and rotary axis. This servo hysteresis deviation is then added to the static structural elastic deformation avoidance displacement in the same dimension. The closed-loop output is the tool displacement deviation offset at the current machining node. This offset value is then assigned in-situ to the dynamic physical deviation factor in the hierarchical adaptive control branch, serving as the sole deterministic independent variable input for subsequent state machine transitions. To adapt to non-ideal edge conditions, two targeted auxiliary protection control processes are configured in parallel on the system periphery. The life decay integral operator continuously accumulates the total stroke completed during machining. When the total stroke exceeds the lifespan stroke threshold, the empirical wear sensitivity constant is used. With respect to the preset tool life limit Calculate the one-dimensional monotonically increasing correction coefficient ,in, The correction coefficient is a one-dimensional monotonically increasing factor. Let be the empirical wear sensitivity constant. To specify the total length of the completed stroke, The preset tool life limit is used as the design life, and this correction factor is applied. With dynamic physical deviation factor By multiplying and fusing to increase the displacement bias, the passive resistance to the dulling and degradation of the physical cutting edge is actively mitigated. In the numerical determination of the one-dimensional monotonically increasing correction coefficient, when the total accumulated machining stroke is less than or equal to the preset normal wear critical mileage, the correction coefficient is equal to the sum of the first-order power function product of the baseline value 1.0 and the empirical wear sensitivity constant, the total stroke, and the reciprocal of the preset tool limit design life, to characterize the stable wear state. When the total stroke exceeds the life stroke threshold and enters the severe wear stage, the data bus activates the condition discrimination hardware module and automatically retrieves the preset discrete tool life characteristic matrix, using a cumulative cutting distance of 2000m as the fixed step unit. The wear compensation correction coefficient is adjusted nonlinearly in a stepwise numerical gain manner. This ensures that as the total stroke accumulates monotonically in one direction to the design life end of 20,000 m, the wear compensation correction coefficient gradually increases from a base value of 1.0 to a maximum saturation limit of 1.22 with a progressively increasing discrete gradient. This numerical evolution path rewrites the bias gain weight within the control flow in situ to counteract the severe nonlinear fluctuations in cutting force caused by dulling of the physical cutting edge at the end of its lifespan. Within the final 10 μs control window before outputting the corrected CNC command flow, the solid topology interference arbitration unit uses a signed distance function to traverse and calculate the coordinates of the node to be output, thus solving for the new corrected machining coordinates. The shortest spatial normal distance between the surface and the 3D nominal mesh design surface Once a normal offset is detected that causes the numerical sign to point inside the part material entity and the shortest spatial normal distance is reached, When the absolute value is greater than the zero-level defense threshold of 0.01mm, the topology boundary truncation gate forcibly resets the magnitude of the correction vector and strips the dynamic gain in the path correction vector. The coordinates of the node to be output are axially offset in the opposite direction of the local machining normal vector, forcibly truncated and locked within the allowable safety tolerance zone boundary of 0.005mm. The output correction CNC command stream is delivered to the CNC machine tool drive control bus. In the pre-control command reconstruction stage, the dynamic cutting deformation is inversely canceled by the topology feedforward in-situ reconstruction of the data space, eliminating the physical trajectory lag caused by inertia of the linkage axis system in the machining of variable curvature multi-dimensional curved surfaces. When the CNC system drives the machining, the normal following error of its spatial trajectory decreases from 0.045mm of the traditional machining trajectory to within 0.006mm, and single addition The calculation time for the work node compensation is consistently locked within 12μs, eliminating the numerical divergence and timing delays of traditional calculation methods. This suppresses transient profile overcutting and reduces chatter and tool mark occurrence rates by over 85%. To eliminate the timing mismatch between the total calculation time of 12 microseconds and the 10 microsecond end-truncation control window, this invention employs a feedforward pipeline parallel asynchronous processing mechanism. The complete pre-compensation reconstruction process of a single machining node is decomposed into three stages: spatial feature extraction, conditional branching, and entity topology edge defense. During the operation of the pre-control command flow, the closed-loop calculations of spatial feature extraction and conditional branching are asynchronously reconstructed ahead of time within the preceding interpolation cycle. Meanwhile, the calculations involving signed distance function traversal and truncation gating are handled more efficiently. The physical topology edge defense phase specifically reserves and locks the trigger within the final 10-microsecond transient window before the output correction CNC command stream. This phase alignment is achieved using a dual-level high-speed latch register array at the hardware level. The newly corrected machining coordinates, asynchronously reconstructed within 12μs of the preceding cycle, are stored in the first-level high-speed latch area and suspended until the arrival of the 10μs hard clock interrupt edge of the CNC bus. Within 2ns, the data is then completely moved in parallel to the second-level overcutting check buffer. This ensures that during the signed distance spatial directed distance calculation and interference discrimination within the final 10μs control window, there is no transmission phase lag or pipeline timing discontinuity in the data input source, eliminating the engineering risks of timing divergence in the control system. This approach, through the preceding... By constructing a two-way dependent closed loop of geometric curvature and temporal evolution in the feed data control flow, the CNC machining control chain has the stable ability to self-dissolve the nonlinear dynamic losses of multi-axis linkage actuators within pure digital rules, maintaining a balance between machining trajectory fidelity and CNC interpolation calculation efficiency. The offline engineering calibration path of the first deviation threshold, the second deviation threshold, the constant term, and the control window involves fixing the standard test piece on the CNC machine tool worktable equipped with a triaxial piezoelectric crystal force measuring ring, driving the spindle to carry the target milling cutter through the nominal test trajectory according to the incremental curvature gradient, and using a dynamic sensor to collect the transient stress components of the spindle overhang at different feed speeds. The critical displacement deformation when high-frequency mechanical chatter or reversing overload alarm occurs is determined to be 0.The path correction vector is locked at an upper limit of 0.80 mm. The acceleration overload displacement deformation of the linkage slide table under extreme response conditions is measured as 0.0015 mm / s / m as the basis for the proportional mapping of the constant term. The 10 microsecond interpolation cycle limited by the industrial Ethernet bus protocol of the CNC system is used as the clock synchronization window for the end-of-line limiting and truncation control logic. After the spatial feature extraction and hierarchical control branch calculation are asynchronously reconstructed in the lookahead thread of the interpolation queue, the final safety protection truncation action is completed within the 10 microsecond bus interruption instant before the output correction CNC command stream.

[0042] Example 2: When the system plans the milling path in the CNC milling process of a precision component containing high-frequency variable curvature surfaces, narrow grooves, and multi-dimensional corners, the virtual machining verification unit in the digital instruction verification system performs quantitative testing on the actual instruction following error of the high-frequency variable curvature surface features input to the code parsing bus. The original trajectory input data stream used in this test originates from the three-dimensional nominal machining trajectory of the standard component. The spatial geometric contour of the three-dimensional nominal machining trajectory contains multiple continuous variable-order curves of different orders to simulate the spatial surface topology of complex workpieces. At the same time as acquiring the original position signal, the data parsing module actively superimposes Gaussian spatial trajectory noise with a root mean square amplitude of 0.003mm to the input end and introduces a non-uniform excitation mechanical disturbance of the spindle dynamic balance with a cycle frequency of 150Hz to create a high-interference test environment on the manufacturing site. At this time, the key control parameter for pre-calibration in the control loop, namely the sliding sampling window length, is... Progress of the nominal timing evolution Its value is limited by the highest response frequency of the CNC interpolation of the system and the dynamic delay constant of the servo drive mechanism. It is necessary to reduce the computational load of the multi-axis linkage control unit and the underlying bus communication load while ensuring spatial resolution. The mechanism for determining the control parameters is that when the evolution rate of the geometric spatial curvature of the measured nominal machining trajectory increases or the spindle speed increases, in order to avoid undersampling distortion of the geometric contour features of the discrete tool position sequence, the hierarchical adaptive control branch will adjust the sliding sampling window length. The corresponding number of discrete nodes shifts towards the lower limit of the working range and monotonically shortens the nominal timing evolution progress. Under the current specific processing load condition, the sliding sampling window length will be calculated by this spatial discrete sampling control logic. Five processing nodes were determined, and the initial nominal timing sequence was evolved and lengthened. The set value was determined to be 2ms. To evaluate the operational stability of the multi-axis interpolation correction method and establish causal data evidence for the boundaries of key parameters, the virtual machining verification unit constructed multiple test comparison classification structures with different parameter configurations in parallel. These included a control group without trajectory deviation correction features, a partially missing control group with displacement correction and removal of timing feedback adjustment control steps, an out-of-range lower limit control group with the first curvature threshold reduced to an extremely low value (0.001 mm / s), and an out-of-range upper limit control group with the maximum displacement correction limit increased to an excessively high value (0.180 mm). Simultaneously, the test setup covered machining load levels with three different curvature abrupt change rate parameter gradients: a first test group with a nominal trajectory curvature abrupt change rate of 5.0 mm / s, a second test group with a change rate of 25.0 mm / s, and a third test group with a change rate of 75.0 mm / s. During the digital instruction parsing verification process, the path parsing unit extracted the nominal position coordinate sequence of adjacent machining nodes in the second test group. This sequence included discrete three-dimensional position vectors. , , The geometric space topology analysis operator calculates the current processing node based on the spatial increment relationship between adjacent position vectors. Local geometric curvature value at The unit normal vector of the trajectory's nominal direction The obtained curvature data stream is then imported into a forward timing differential processor, which performs a first-order forward difference operation on the curvature values ​​of consecutive machining nodes to calculate the rate of curvature change between adjacent tool positions. The specific calculation formula is as follows: ,in, For the current processing node The rate of change of curvature at that point For the current processing node The local geometric curvature value at that point, This represents the local geometric curvature value at the previous processing node. The nominal timing evolution between two adjacent processing nodes is increased.

[0043] During the operation of the feedforward control flow, the control unit intercepts the current processing node output by the forward timing differential processor. rate of change of curvature at The index was measured to have a stable value of 24.7 per millisecond, and the rate of change of curvature was determined. The nominal feed rate value set in the current machining command Import hierarchical control branches to perform cascaded state determination and solve dynamic physical deviation factors. When the verification system switched to the third test group condition to handle high machining loads, the measured transient rate of change of curvature was... The value is increased to 74.5 milliseconds, which crosses the preset second curvature gradient threshold, thereby forcibly triggering the hard safety limit cutoff action in the graded control branch and causing the control unit to adjust the dynamic physical deviation factor. To maintain the stiffness stability of the multi-axis slide mechanism, the displacement offset limit is set at 0.080 mm. Correspondingly, the control group exceeding the upper limit, having removed the 0.080 mm displacement offset limit and set the maximum position correction breakpoint to 0.180 mm, outputs a dynamic physical deviation factor as high as 0.146 mm to the path correction flow under high machining load conditions. This leads to excessive single-time spatial displacement entrainment in the multi-axis linkage system, exceeding the stiffness load limit of the CNC slide table. This causes high-frequency continuous chatter in the mechanical shaft system and overcut contour damage on the workpiece surface. It exhibits a nonlinear, abrupt increase in geometric following deviation as the position correction exceeds the limit. Therefore, at the data level, it is confirmed that the 0.080mm cutoff threshold is the upper limit of the critical working window that balances slide table stiffness constraints and trajectory approximation accuracy. Furthermore, the control group exceeding the lower limit, by reducing the first curvature threshold to 0.001 per millimeter, experiences frequent triggering of erroneous graded responses by background Gaussian spatial trajectory noise, increasing the dynamic physical deviation factor. In the gently curving trajectory region, irregular jumps and redundant axis commutation oscillations occur. Simultaneously, in some missing control groups, the data path reconstruction operator operates based on the unit normal vector. The calculated three-dimensional physical backoff correction vector has an amplitude of 0.052 mm. Subsequently, due to the lack of a process to extend the nominal timing evolution at the next processing node... The in-situ amplified 1.5x reverse interference feedback adjustment control step caused the shaft drive mechanism to be unable to decelerate through the curvature abrupt change region in the time domain, which in turn affected the curvature change rate acquired by the forward timing differential processor at subsequent machining nodes. The value surged to 141.8 milliseconds, causing a computational overflow defect in the digital interpolation circuit, where the value exceeded the maximum allowable range of the register.

[0044] When the data path reconstruction operator obtains a dynamic physical deviation factor that meets stiffness constraints Then, the synthesized three-dimensional physical retraction correction vector is directly applied. Compared with the original position vector The control code's data structure is rewritten by performing same-dimensional tensor summation within the data bus, reconstructing the tool position data stream, and outputting a novel compensated machining coordinate system with physical retraction pre-compensation features. ,in, For new types of machining coordinate correction, For the original position vector sample group, The three-dimensional physical setback correction vector is used to prevent numerical divergence. The newly generated machining coordinates are injected in reverse as a termination constraint for the sliding window sampling process. Simultaneously, in continuous milling tests where the multi-axis feed slide operates under high load for 120 hours, the machining stroke accumulation logic continuously accumulates the total machining stroke. This parameter is then monotonically increased to 15000m, and is used as a one-dimensional monotonically increasing correction coefficient for the numerator term. In the calculation formula, the correction coefficient is... The axial nonlinearity is adjusted from an initial 1.0 to 1.22 as the continuous milling time increases, through a dynamic physical deviation factor. By integrating the product topology to increase the actual correction vector magnitude of the current node, this neutral physical quantity correction is used to offset the increased transient cutting force deviation caused by physical tool wear and degradation. When finally completing the high-fidelity trajectory tracking test of the output CNC command stream for each test group and control group, the results show that the control group without correction features has a maximum normal following error of 0.046mm, 0.068mm, and 0.085mm under low, medium, and high intensity conditions, respectively. The partially missing control group still has a maximum geometric following error of 0.039mm under high intensity conditions, and the correction path produces irregular serrated burrs induced by computational overload. In contrast, the final measured normal following errors of the first, second, and third test groups corresponding to the experimental group of this invention are controlled at 0.003mm, 0.005mm, and 0.006mm, respectively, demonstrating a monotonic deterministic law of controlled convergence of the following error with increasing curvature gradient under abrupt changes in curvature. Simultaneously, single-addition... The pre-compensation calculation time of the work node is kept constant within 12μs, the occurrence rate of chatter and tool marks on the part surface is reduced by 85.3%, and the transient overcut phenomenon on the workpiece surface is suppressed. The aforementioned multi-dimensional quantitative test and the operation of multiple sets of control systems show that by reconstructing the front end of CNC instruction machining and combining the bidirectional dependent closed-loop control flow of geometric curvature mutation rate and adaptive timing evolution step size, it is possible to change the spatial lag state of the servo linkage drive axis system by using the topological feedforward calculation of the data control code space without modifying the mechanical transmission hardware of the CNC machine tool. This data processing method, which directly converts the spatial discrete geometric analytical characteristics into the time domain feed step size adaptive adjustment, reduces the data island effect between the spatial geometric discrete sampling of the CNC machining instruction layer and the intrinsic lag characteristics of the mechanical dynamics of the drive axis linkage mechanism. In the pure digital control code generation stage, an adaptive and coordinated balance is achieved between the component trajectory following machining fidelity and the real-time interpolation calculation time of the CNC system.

[0045] Example 3: This example combines Figures 1 to 2 The milling path correction method for CAM is explained, such as... Figure 1As shown, the method includes steps S101: parsing the original CNC command stream, obtaining the nominal coordinate sequence and nominal machining speed, and establishing the data basis for digital trajectory generation and reconstruction; step S102: calculating the distance between two adjacent points in the nominal coordinate sequence through the trajectory curvature calculation model to accurately determine the spatial curvature variation reflecting the characteristics of shaft dynamics variation; step S103: simultaneously solving the tool displacement deviation offset based on the machine tool axial kinematic constraints and structural stiffness characteristics, and using the machining stroke accumulation logic to nonlinearly increase and correct the offset when the total stroke exceeds the life stroke threshold by using the wear compensation correction coefficient; and step S104: calculating the path correction vector through hierarchical adaptive control branches and reconstructing the correction coordinate sequence, using the overcutting interference verification logic to activate the amplitude limiting truncation when the shortest normal distance indicates intrusion into the entity and the absolute value is greater than 0.01mm, stripping the dynamic gain and trunculating to within the 0.005mm tolerance zone boundary, and outputting the corrected CNC command stream.

[0046] like Figure 2 As shown, the framework consists of instruction parsing and feature extraction, hierarchical adaptive control reconstruction, physical deviation calculation and correction, and entity topology edge defense. Instruction parsing and feature extraction includes nominal coordinate and velocity analysis, determination of spatial curvature variation, and identification and elimination of overlapping and redundant points. Hierarchical adaptive control reconstruction includes determination of dynamic physical deviation factors, path correction vector rewriting and reconstruction, and reverse fine-tuning of nominal time step size. Physical deviation calculation and correction includes the introduction of axial kinematic constraints, simultaneous calculation of structural stiffness features, and correction of total travel and wear accumulation. Entity topology edge defense includes importing three-dimensional topology mesh data, calculation of the shortest signed distance normal, and truncation of safety limiting boundary control. Ultimately, it achieves output correction of CNC instruction flow to eliminate lag in physical trajectory of variable curvature machining, coordinate path fidelity, and improve interpolation calculation efficiency.

[0047] Example 4: In the data preparation scenario of a computer-aided manufacturing digital instruction verification system performing pre-correction on a milling path for a complex variable curvature surface, the linkage shaft control unit pre-reads and loads the first curvature threshold, the second curvature threshold, and the constant term in the speed weight term contained in the hierarchical control branch. Compared with the empirical wear sensitivity constant in the tool wear term If the aforementioned control limits and correction coefficients are given directly as static constants, the downstream control system will face the risk of data mismatch due to variations in the rigidity characteristics of different machine tool structures and the physical intrinsic properties of the cutting tools. Furthermore, traditional parameter determination methods often rely on offline manual operation of machine tool cutting trial and error, which involve lag and lack causal quantitative data support. As a result, when the tool position data reconstruction operator deals with the nonlinear dynamic losses of the machine tool linkage mechanism, it exposes a technical gap due to the unclear reference of the pre-input data, which in turn causes the closed-loop tracking instability of the entire machining trajectory data control flow under complex corner conditions.

[0048] To establish the quantitative numerical source of the aforementioned key control factors and to build a data correlation link between the intrinsic parameters of the machine tool structure and the calculation of the digital path correction vector, the offline calibration operator reads the inherent functional specifications of the multi-axis machine tool slide assembly, that is, sets the spindle overhang end at the unit normal vector. Static stiffness measurement in the direction The value is 45.0 N / micrometer. Simultaneously, the geometric diameter and rake angle specifications of the selected end mill made of high-speed steel or cemented carbide are acquired. The aforementioned machine tool axial kinematic constraints and structural stiffness characteristics are used as boundary inputs and imported into the parameter calibration loop of the hierarchical control branch. For the engineering calibration of the first and second curvature thresholds, the calibration loop drives the standard specimen mounted on the worktable through multiple sets of nominal discrete curves with preset curvatures in an increasing gradient. Transient cutting force data is collected in real time by a piezoelectric dynamic sensor installed on the machine tool spindle force measuring ring. The critical curvature physical inflection point when the transient cutting force undergoes a nonlinear upward abrupt change is used as the working window boundary of the cascaded state judgment rule, thereby determining the discrete calibration value of the first curvature threshold to be 0.050 N / mm and the discrete calibration value of the second curvature threshold to be 0.450 N / mm. The specific calculation relationship is expressed by the formula: ,in, For the current processing node Rate of change of curvature at point, subscript For processing node index, For the current processing node The local geometric curvature value at that point, This represents the local geometric curvature value at the previous processing node. The nominal timing evolution between two adjacent processing nodes is increased, followed by a constant term. Quantization reconstruction is achieved by adjusting the linkage slide at the nominal feed speed value. The transient acceleration overload deformation at the limit response feed rate is used as the target causal quantity for inverse mapping. Under the purely textual linear transmission formula, the measured shaft elastic displacement deformation of 0.0015 mm / s / m at unit velocity is transferred to the constant term. This is used to establish the dynamic physical deviation factor. Proportional mapping basis, dynamic physical deviation factor The unit is millimeters; for empirical wear sensitivity constants The determination of the life decay integral operator within the preset tool limit design life. Under a constraint of 20,000 meters, the residual deformation of the standard specimen in the finishing normal direction was measured in stages every 2,000 meters of machining stroke. The total stroke of multiple sets was then calculated using the least squares method. The contour error under the gradient is fitted with a monotonic function, and finally the empirical wear sensitivity constant used to characterize the effect of physical edge dulling on the sudden change in cutting force is calculated. The empirical wear sensitivity constant is 0.15. As dimensionless constants, the selection criteria and engineering significance of the aforementioned key process parameter group are clear in actual measurements and theoretical boundary analyses: the first curvature threshold is set at 0.050 per millimeter; if it is below this lower limit, background Gaussian spatial trajectory noise will frequently exceed the limit, triggering graded responses and causing unnecessary axial commutation oscillations in the shaft system; the second curvature threshold is set at 0.450 per millimeter; if it is above this upper limit, the multi-axis linkage shaft system will experience ultimate overload impact due to exceeding the stiffness bearing limit; the constant term is set at 0.0015 millimeters per second per meter, which is for... The engineering proportionality coefficient is determined by inverse mapping of the acceleration overload displacement deformation of the linkage slide under the nominal feed speed limit; the empirical wear sensitivity constant of 0.15 is obtained by fitting and differentiating the monotonic function of the finishing normal offset residual deformation under 10 discrete stroke gradients from 2000 meters, 4000 meters to 20000 meters using the least squares method when the milling cutter reaches the end of its design life of 20000 meters in cumulative machining stroke. This ensures that the compensation gain can effectively compensate for the machining accuracy decay caused by tool wear.

[0049] Through the aforementioned closed and reproducible engineering calibration process, the obtained calibration process control parameter group is written in situ into the non-volatile configuration register of the data path reconstruction operator, enabling the newly generated corrected machining coordinates to be reconstructed. The data architecture is supported by complete and unambiguous underlying physical feature data, which eliminates the control code reconstruction divergence defects caused by parameter suspending in the feedforward pre-compensation stage of the machining system. In the actual digital control code flow and milling correction operation, it guides the linkage mechanism to offset mechanical response dissipation and suppresses the transient contour overcut phenomenon on the surface of the part, maintaining a balance between machining trajectory following machining fidelity and CNC interpolation calculation efficiency.

[0050] Example 5: In a CNC cutting path reconstruction deployment scenario facing transient excitation and zero-position drift interference, the linkage axis control unit prioritizes static benchmark calibration of the sensor to eliminate the initial bias voltage before calculating the corrected coordinates. This calibration is initiated when the worktable is unloaded and the feed rate is 0.0 mm / s. The control unit continuously reads the original voltage of the channel over 500 cycles and calculates the mean. When it is detected that the variance of this mean is less than the preset tolerance for 5 consecutive windows, the mean is locked in place as the noise floor benchmark value and in-situ differential offset is achieved in the signal flow of subsequent milling operations, thereby enabling the forward timing differential processor to extract the rate of curvature change. Provides unbiased input variables.

[0051] When the system sends the above control command stream to the multi-axis linkage slide mechanism, the control unit intercepts the rate of curvature change of the current machining node extracted by the processor. And establish the nominal feed rate value Complete the hierarchical reconstruction, and the displacement compensation amount is based on the existing mapping formula. The dynamic physical deviation factor was calculated. ,in, For dynamic physical deviation factor, For constant terms, To represent the nominal feed rate value and to prevent timing delay defects, a new type of corrected machining coordinate is generated by summing the data path reconstruction operator. The original position data is directly rewritten and delivered to the servo drive component to replace the mechanical loss of the axis at the front end, so that the following normal error between the actual trajectory of the finished component surface and the design surface monotonically decreases and remains constant within 0.006mm.

[0052] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit of this application and the scope of protection of this invention, and all of these forms are within the protection scope of this application.

Claims

1. A CAM-based milling path correction method, characterized in that, Includes the following steps: Step S101: Parse the original CNC instruction stream to obtain the nominal coordinate sequence and nominal machining speed; Step S102: The distance between two adjacent points in the nominal coordinate sequence is calculated by differential calculation using the trajectory curvature calculation model to determine the spatial curvature variation. Step S103: Based on the machine tool axial kinematic constraints and structural stiffness characteristics, the tool displacement deviation offset is calculated simultaneously, and the total amount of processed stroke is continuously accumulated through the processing stroke accumulation logic. When the total stroke exceeds the life stroke threshold, the tool displacement deviation offset is nonlinearly increased and corrected using the wear compensation correction coefficient. Step S104: Through hierarchical adaptive control branches, the path correction vector is calculated based on the spatial curvature variation and the corrected tool displacement deviation offset, and the nominal coordinate sequence is reconstructed to generate the correction coordinate sequence. The shortest normal distance between the correction coordinate sequence and the model mesh surface is calculated through overcutting interference verification logic. When the shortest normal distance indicates that the correction coordinate sequence has invaded the interior of the material entity and the absolute value is greater than 0.01mm, the safety limit truncation control logic is activated and the dynamic gain in the path correction vector is stripped off. The correction coordinate sequence is truncated to the 0.005mm tolerance zone boundary, and the corrected CNC command flow is output.

2. The CAM-based milling path correction method according to claim 1, characterized in that, Step S104 includes the following steps through the hierarchical adaptive control branch: Step S1041, when the tool displacement deviation offset does not cross the first deviation threshold, the path correction vector is kept at 0mm; Step S1042, when the tool displacement deviation offset is between the first deviation threshold and the second deviation threshold and the nominal machining speed exceeds the speed threshold, the path correction vector is linearly increased as the tool displacement deviation offset increases; Step S1043, when the tool displacement deviation offset crosses the second deviation threshold, the path correction vector is truncated and locked to 0.080mm.

3. The CAM-based milling path correction method according to claim 1, characterized in that, Step S102 involves calculating the distance between two adjacent points in the nominal coordinate sequence using a trajectory curvature calculation model to determine the spatial curvature variation. This includes the following steps: Step S1021: Extracting three consecutive adjacent nominal coordinate points from the nominal coordinate sequence to construct a preceding chord vector and a following chord vector; Step S1022: Calculating the angle variation between the preceding and following chord vectors and the chord length proportionality coefficient; Step S1023: Calculating the local curvature value at each nominal coordinate point based on the angle variation and the chord length proportionality coefficient, and using a second-order difference algorithm to calculate the rate of change of the local curvature value between adjacent nominal coordinate points, which is then used as the spatial curvature variation.

4. The CAM-based milling path correction method according to claim 1, characterized in that, Includes the following steps: Step S105: After generating the nominal coordinate sequence in step S101 and before using the nominal coordinate sequence in step S102, calculate the Euclidean distance between adjacent nominal coordinate points in the nominal coordinate sequence. When the Euclidean distance is less than 0.001 mm, the current nominal coordinate point is determined to be a coincident redundant point and is removed.

5. A CAM-based milling path correction method according to claim 1, characterized in that, Step S104 involves calculating the shortest normal distance between the corrected coordinate sequence and the model mesh surface using overcutting interference verification logic, which includes the following steps: Step S1044: Import the 3D topological mesh data corresponding to the model mesh surface of the part; Step S1045: Within a 10μs control window before outputting the corrected CNC command stream, use a signed distance function to traverse and calculate the coordinates of the nodes to be output in the corrected coordinate sequence; Step S1046: Calculate the shortest spatial geometric distance between the coordinates of the nodes to be output and the model mesh surface, and use the sign of the normal vector of the shortest spatial geometric distance as the interference criterion. When the sign of the normal vector points to the interior of the part entity, the shortest spatial geometric distance is determined as the shortest normal distance.

6. The CAM-based milling path correction method according to claim 1, characterized in that, Step S104, which truncates the corrected coordinate sequence to within the 0.005mm tolerance zone boundary, includes the following steps: Step S1047, when the safety limit truncation control logic is activated, extract the local machining normal vector at the coordinates of the node to be output; Step S1048, obtain the maximum allowable tolerance value of 0.005mm, and apply an axial offset to the coordinates of the node to be output along the opposite direction of the local machining normal vector, locking the offset coordinates within the tolerance zone boundary.

7. A CAM-based milling path correction method according to claim 1, characterized in that, The calculation of the path correction vector in step S104 also includes the following steps: Step S1049, calculate the absolute value of the spatial curvature variation in real time. When the absolute value increases monotonically, reduce the nominal processing speed of the corresponding processing node and simultaneously increase the gain control parameter in the hierarchical adaptive control branch.

8. A CAM-based milling path correction method according to claim 1, characterized in that, Step S103 involves simultaneously calculating the tool displacement deviation offset based on the machine tool's axial kinematic constraints and structural stiffness characteristics, including the following steps: Step S1031, obtaining the real-time geometric motion transfer matrix of each rotary axis and linear axis of the CNC machine tool; Step S1032, projecting the displacement components between adjacent nominal coordinate points onto each motion axis, calculating the servo hysteresis deviation of each linear axis under dynamic reversal conditions, and superimposing the servo hysteresis deviation into the tool displacement deviation offset.

9. A CAM-based milling path correction method according to claim 1, characterized in that, Includes the following steps: Step S106: After the modified CNC instruction stream is output in step S104, the modified CNC instruction stream is imported into the machine tool post-processing module, converted into a machining code file that conforms to the CNC system reading specifications, and sent to the control bus of the CNC system.

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