NC Motion Control with Reverse Interpolation Speed Planning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing numerical control devices face challenges in efficiently controlling the movement of machine tools, as sudden changes in velocity or acceleration can lead to malfunctions, such as breakdowns or deviation from the ideal movement path. Additionally, the constant velocity and acceleration values within each interval may not be ideal, potentially increasing movement time or requiring excessive calculation for velocity curve calculation.
Innovation Solution
A numerical control device that reads an NC program and processes blocks sequentially, using a reading part, decision part, first and second calculation parts, and reverse interpolation part to calculate rise velocities and interpolation points. This device performs acceleration/deceleration processes based on maximum jerk, current velocity, and acceleration, ensuring the movement part follows a calculated velocity curve without exceeding permissible limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the width of the interval is large, then the amount of calculation is reduced, but the movement time increases because the velocity does not increase to the ideal velocity
Solution Approach 1:
The patent divides the movement path into multiple intervals and performs velocity curve calculations for each interval separately. By segmenting the calculation process, the system can use larger interval widths to reduce computational load while still achieving accurate velocity control through cumulative calculation across segments, thereby reducing movement time without excessive computation.
Solution Approach 2:
The patent performs preliminary velocity curve calculations for look-ahead blocks before actual movement occurs. This allows the system to pre-determine optimal velocity profiles for upcoming intervals, enabling the movement part to reach ideal velocities more quickly while maintaining calculation efficiency through advance planning rather than real-time computation.
2Manufacturing precision
If the width of the interval is narrowed, then the difference between calculated permissible values and ideal permissible values is reduced, but the amount of calculation increases
Solution Approach 1:
The movement path is divided into multiple intervals where velocity curve calculations are performed separately for each segment. This segmentation allows the system to maintain reasonable interval widths that balance precision requirements with computational efficiency, as each segment can be calculated independently without requiring fine-grained division of the entire path.
Solution Approach 2:
The patent calculates velocity curves for look-ahead blocks that extend beyond the immediately current block. This partial excessive action ensures that velocity control precision is maintained for upcoming movements without requiring the entire path to be divided into very small intervals, thus reducing overall calculation complexity while achieving sufficient precision.
3Productivity
If the velocity is increased to reduce movement time, then productivity improves, but the risk of malfunctions increases due to sudden changes in velocity or acceleration
Solution Approach 1:
The patent dynamically adjusts the velocity profile for the movement part by calculating optimal velocity curves that consider maximum permissible velocity, acceleration, and jerk values. This dynamic velocity adjustment allows the system to operate at high speeds while smoothly transitioning between velocity changes, preventing sudden shocks that could cause malfunctions and maintaining both productivity and reliability.
Solution Approach 2:
The system performs preliminary calculations of velocity, acceleration, and jerk profiles before executing movement. By pre-determining the optimal velocity curve that respects all operational limits, the system can safely operate at maximum permissible speeds without risking sudden excessive changes that would compromise reliability, thus achieving high productivity with maintained system safety.
Data Source
AI summary
Provided are a numerical control device, a machine tool, a numerical control method, and non-transitory computer readable medium contributing in achieving that an increase in moving time of a moving part is suppressed while suppressing the amount of computation for calculating a speed curve prior to acceleration/deceleration processing. A CPU reads the current block (Nnow) and a prefetch block and determines a target block (Nd) and a target speed (Vd) at a command point for the target block (Nd). The CPU calculates a first rising speed (V1) at the position where tip acceleration becomes zero from the current tip acceleration. The CPU calculates a reverse interpolation point (Prev). Every time when the reverse interpolation point (Prev) is calculated, the CPU calculates a second rising speed (V2) at the position where the tip acceleration becomes zero from the tip acceleration at the reverse interpolation point (Prev).