Numerical Controller Segment Curve Creation for Machining Accuracy
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Solution Overview
Problem
Conventional numerical controllers face challenges in creating machining curves efficiently, particularly when dealing with large numbers of command points, leading to deceleration and inaccuracies due to insufficient capacity and errors in point sequence variations.
Innovation Solution
A numerical controller with a machining curve creating function that divides the command point sequence into segments, creating segment curves with continuous second-derivative vectors, allowing for the connection of cubic curves to form a machining curve without reading all command points, thus reducing computational load and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If all command points are read to create a machining curve, then manufacturing precision is improved, but productivity deteriorates due to deceleration and long processing time
Solution Approach 1:
The patent divides the command point sequence into multiple segments, where each segment contains a limited number of command points (e.g., 3-5 points). Segment curve creation is performed independently for each segment, allowing parallel processing and reducing the total computation time. This segmentation enables the system to maintain high precision while improving productivity by avoiding the need to process all points sequentially.
2Manufacturing precision
If cubic curves are connected to form machining curve, then manufacturing precision is improved with smooth curves, but device complexity increases due to continuous second-derivative calculations
Solution Approach 1:
The patent applies partial action by calculating continuous second-derivative vectors only at the boundary points between segments rather than at every command point. This approach maintains the smoothness of the machining curve while significantly reducing the computational complexity. The segment curve creation uses simplified calculations for interior points of each segment, reserving the complex continuous derivative calculations only where necessary at segment boundaries.
3Productivity
If maximum number of command points are included in segment curve, then productivity is improved by reducing segment count, but manufacturing precision deteriorates due to increased approximation error
Solution Approach 1:
The patent dynamically adjusts the segment curve parameters including the number of command points per segment, the permissible distance threshold, and the cubic function coefficients. By optimizing these parameters, the system can include more command points in each segment (improving productivity) while maintaining the distance between the segment curve and command points within acceptable limits (preserving precision). The system allows flexible parameter configuration to balance productivity and precision requirements.
Data Source
AI summary
Provided is a numerical controller having a machining curve creating function. A command point sequence is divided into a plurality of segments and a segment curve corresponding to each segment command point sequence is created. The segment curve is created so that a distance of the segment curve from the segment command point sequence is within a permissible value set in advance, and the maximum number of command points are included between a starting point and an ending point of the segment command point sequence. This process of segment curve creation is repetitively executed from the starting point to the ending point of the command point sequence to create a machining curve. Subsequently, the machining curve is interpolated and drive axes of a machine tool are moved to the interpolated positions on the machining curve.