Numerical Controller for Multi-Axis Deformation Error Correction
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Solution Overview
Problem
Existing numerical control systems struggle to effectively reduce machining errors caused by deformation of mechanical structures during axis motion, especially when the error direction does not align with the motion direction.
Innovation Solution
A numerical controller that includes a model holding unit to simulate mechanical structure deformation, a machining error estimation unit to calculate error direction and amount, and a correction amount arithmetic unit to determine necessary corrections for axis commands, thereby reducing machining errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a motor controller corrects position command by multiplying axis acceleration by a gain, then correction is performed in the direction of axis motion, but machining error in directions other than the motion direction cannot be reduced
Solution Approach 1:
The invention extends correction from one-dimensional axis motion direction to three-dimensional tool displacement direction by calculating error components in X, Y, and Z directions separately, then synthesizing the total error vector to determine the appropriate correction amount and direction
Solution Approach 2:
The invention changes the correction parameter from simple acceleration-based correction to a comprehensive model-based correction that considers the relationship between axis acceleration and tool displacement in multiple directions, using a gain value that accounts for the mechanical structure's deformation characteristics
2Reliability
If normal feedback control is used with detectors attached to axes, then position control is achieved, but machining errors due to mechanical structure deformation cannot be detected or corrected
Solution Approach 1:
The invention introduces a machining error estimation unit as an intermediary that calculates expected machining errors based on axis acceleration and mechanical structure characteristics, bridging the gap between feedback control data and actual machining quality by predicting errors in directions not directly measured by detectors
Solution Approach 2:
The invention performs preliminary correction by estimating machining errors before actual machining occurs, using the relationship between axis acceleration and tool displacement to proactively adjust commands and prevent machining defects
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution enables the numerical controller to accurately estimate and correct machining errors due to mechanical structure deformation, thereby improving machining precision and reducing defects.
Implementation Method 1
a machine model that simulates deformation of the mechanical structure accompanying the motion of the mechanical structure in axial directions and represents an error amount as an amount of displacement of the tool in the axial directions due to the deformation of the mechanical structure
Data Source
AI summary
A numerical controller includes: a model holding unit that holds a machine model, the machine model being a model that simulates deformation of a mechanical structure accompanying motion of the mechanical structure in axial directions and representing an error amount as an amount of displacement of a tool; a machining error estimation unit that estimates an error direction and the error amount in the error direction on the basis of axis data that is data on drive of a drive mechanism and the machine model, the error direction being a direction in which displacement of the tool occurs among the axial directions; and a correction amount arithmetic unit that selects one or more of the axes subject to correction, and performs arithmetic to find a correction amount used for correction of a command to be output to the drive mechanism for the axis selected.