Corner Feedrate Planning for Curved Machine Tool Paths
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Solution Overview
Problem
Existing methods for rounding corner parts in industrial machines fail to effectively control feedrate, leading to speed waveforms with potential shocks and decreased machining accuracy.
Innovation Solution
A control device that analyzes commands, detects corner parts, forms a reference curve through acceleration/deceleration processing, and plans speed distribution to smooth the transition, using a corner curve shaper and curve speed planner to stabilize speed changes and reduce shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a circular arc, spline curve or clothoid curve is used to round the corner part, then the corner shape is rounded smoothly, but the speed waveform becomes wavy causing shocks and decreased machining accuracy
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal speed values at each position along the rounded corner path in a lookup table before machining begins. This allows the control system to directly retrieve and apply pre-optimized speed values during machining, preventing speed waveform irregularities and shocks while maintaining smooth corner rounding.
Solution Approach 2:
The patent changes the speed parameter dynamically based on position along the corner path. By storing position-speed correspondence data in the lookup table and retrieving appropriate speed values based on current position, the system optimizes speed distribution to maintain smooth acceleration and deceleration throughout the corner rounding process, eliminating wavy speed patterns.
2Manufacturing precision
If feedrate is reduced at corner parts to prevent shocks, then machining accuracy is maintained, but productivity decreases
Solution Approach 1:
The system performs preliminary calculation and storage of optimal speed values for all positions along the corner path before machining. This pre-computed lookup table enables the control system to maintain optimal speeds without real-time complex calculations, achieving both high precision and productivity by eliminating unnecessary speed reductions while preventing shocks through pre-planned speed distribution.
Solution Approach 2:
The patent creates a copied representation of the optimal speed profile in the lookup table, which can be quickly referenced during machining without requiring repeated complex calculations. This copying approach allows rapid retrieval of speed values, maintaining high productivity while ensuring precision through consistent application of pre-optimized speed data.
Data Source
AI summary
A control device according to the present disclosure includes: an analysis unit that analyzes instructions by a control program; a corner detection unit that detects, on the basis of the analysis result by the analysis unit, a corner portion at which the direction of a moving route becomes discontinuous; a reference curve creation unit that performs acceleration/deceleration processing on movements before and after the corner portion on the moving route and that creates, as a reference curve, a curve obtained by overlapping the movements by an amount corresponding to a predetermined overlap period; a corner curving unit that creates a moving route curved by inserting, in the corner portion, a curve passing through at least one predetermined reference position on the reference curve; and a curve velocity planning unit that creates a velocity plan relating to movement on the curved moving route. The curve velocity planning unit determines the velocity at the reference position during the movement on the moving route, on the basis of the moving velocity at the reference position on the reference curve.