Numerical Controller Path Correction for Interference Avoidance
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Solution Overview
Problem
In simultaneous positioning commands for multiple axes, existing technologies face challenges in preventing tool-workpiece interference while maintaining short cycle times, as they often require linear interpolation and fixed-time acceleration/deceleration, leading to longer cycle times and potential collisions.
Innovation Solution
A numerical controller with a command analysis unit and path correction unit that analyzes program commands to generate move command data and correction paths, allowing for non-linear interpolation positioning and delaying the start timing of axes to avoid interference, thereby setting the shortest time constant for each axis and preventing collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear interpolation positioning with fixed-time acceleration and deceleration is used to prevent tool-workpiece interference, then reliability is improved, but productivity deteriorates due to longer cycle times
Solution Approach 1:
The patent changes the acceleration and deceleration parameters by allowing different time constants for different axes (Tx for X-axis, Tz for Z-axis) instead of using fixed-time acceleration. This enables each axis to be optimized independently, preventing tool-workpiece interference while minimizing cycle time extension
Solution Approach 2:
The patent introduces dynamic path correction that bends the tool path away from the workpiece when interference is detected. This dynamic adjustment of the tool path allows the system to avoid collisions without requiring conservative fixed-time acceleration, thereby maintaining shorter cycle times while ensuring reliability
2Productivity
If each axis uses its own time constant for acceleration and deceleration in non-linear interpolation positioning, then productivity is improved with shorter cycle times, but reliability deteriorates due to potential tool-workpiece interference
Solution Approach 1:
The patent implements a path correction unit that continuously monitors the tool path and workpiece position, and automatically bends the path away from the workpiece when interference is predicted. This feedback mechanism ensures reliability is maintained even when using optimized individual axis time constants for productivity
Data Source
AI summary
A numerical controller controls a machine tool that has a plurality of axes based on a program command. The numerical controller analyzes the program command. When the program command contains a positioning command, the numerical controller generates a correction path bent in a direction going away from the workpiece with respect to a straight-line path toward a commanded position from a current position of the tool that machines the workpiece, and controls respective axes of the machine tool based on the generated correction path.