Numerical Controller Speed Profiling for Accurate Curve Machining
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Solution Overview
Problem
Numerical controllers face challenges in machining programs where excessive speed and acceleration can exceed driving axis capacity and cause vibrations, leading to errors in movement paths, particularly when executing arcuate movements.
Innovation Solution
A numerical controller and program that calculate a synthetic speed for curve blocks, initially accelerating from zero and then decelerating to zero using a prior revision time constant, and calculate prior revision speeds for each driving axis to achieve this synthetic speed, reducing excessive speed and acceleration while minimizing path deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acceleration/deceleration process is performed for each block of machining program, then speed and acceleration are controlled within driving axis capacity, but movement path deviates from designated path particularly when moving target to describe an arc
Solution Approach 1:
The patent applies preliminary action by calculating and storing speed data for decelerating and stopping at the ending point of the immediately preceding block before executing the current block. This allows the acceleration/deceleration process to account for future stopping requirements, preventing excessive speed accumulation and reducing movement path deviation, particularly during arcuate movements.
2Manufacturing precision
If time constant of acceleration/deceleration upon start of block is reduced to reduce path error, then movement path accuracy improves, but excessive speed and acceleration may be required that exceeds driving axis capacity or causes vibration
Solution Approach 1:
The patent performs preliminary calculation of speed data required for decelerating and stopping at the ending point of the immediately preceding block. This pre-calculated speed data is then added to the speed data for increasing speed from zero at the start of the current block, ensuring that the combined speed profile does not exceed driving axis capacity or cause vibration, while still achieving accurate movement path following.
Data Source
AI summary
A numerical controller 10 according to an aspect of the present disclosure does not require excessive speed and acceleration yet suppress errors in movement paths, and in accordance with a machining program containing a plurality of command blocks that each specify a designated speed of a target, controls a machining device having a plurality of driving axes for driving the target. The numerical controller 10 comprises: a synthetic speed calculation unit 16 that, for at least a curve block which designates curve movement and which is from among the plurality of command blocks, calculates a synthetic speed that is revised so that the designated speed is initially accelerated from zero by a prior revision time constant and finally decelerated to zero by the prior revision time constant; and a prior revision speed calculation unit 17 that calculates a prior revision speed of each driving axis for each time to realize the synthetic speed.