Numerical Controller Tool Path Interpolation Using Arc Intersection Points
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Solution Overview
Problem
Conventional numerical controllers face challenges in accurately interpolating command points to improve the quality of machining surfaces, often resulting in uneven steps between adjacent tool paths due to uneven command point densities, which complicates the smoothing process and requires high processing capabilities.
Innovation Solution
A numerical controller that creates additional command points based on existing sequences by calculating intersection points between arcs and perpendicular bisectors of line segments, allowing for accurate interpolation without referencing adjacent paths, thereby improving the restoration of the ideal curve and reducing step disorders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional smoothing functions use spline curves to output smooth tool paths, then the output appears smooth, but the spline curve does not accurately restore the ideal curve and causes disorder of steps between adjacent paths
Solution Approach 1:
The patent segments the tool path into multiple paths and processes each path independently through interpolation, rather than using a global spline curve. This segmentation allows accurate restoration of the ideal curve while maintaining smoothness, as each path is interpolated based on its own command points without being distorted by adjacent paths' variations.
2Ease of manufacture
If the densities of command points are uneven between adjacent paths, then the command point sequence is simpler to generate, but large steps occur between adjacent paths reducing machining surface quality
Solution Approach 1:
The patent performs preliminary interpolation processing on each command point sequence independently before combining the paths. By pre-processing each path to ensure accurate ideal curve restoration through intersection point calculation, the system eliminates step disorders between adjacent paths while maintaining the ease of command point generation.
3Measurement precision
If CAM tolerance is reduced and the number of command points is increased to avoid smoothing function problems, then the accuracy of command point representation improves, but high processing capability is required
Solution Approach 1:
The patent changes the parameter representation by using intersection points of arcs and perpendicular bisectors instead of traditional spline curve parameters. This mathematical transformation maintains high accuracy in command point representation while improving processing efficiency, as the interpolation calculation based on intersection points is computationally more efficient than conventional spline methods.
Data Source
AI summary
A numerical controller that creates a tool path from a plurality of command points includes: a command point sequence acquisition unit that acquires an existing command point sequence; a command point creating unit that creates at least one additional command point, based on the existing command point sequence; and an interpolation processing unit that interpolates the existing command point sequence and the additional command point to create the tool path. The command point creating unit outputs, as the additional command point, an intersection point Q1 between an arc C1 passing through consecutive three command points, P0, P1 and P2, in the existing command point sequence and a perpendicular bisector of a line segment whose end points are P1 and P2.