Five-Axis Numerical Controller Axis-Dependent Error Compensation

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Solution Overview

Problem

Conventional numerical controllers for five-axis machining tools fail to accurately compensate for both translational and rotational errors, particularly when machining with a side face or drilling, leading to insufficient precision due to uncorrected tool orientation errors.

Innovation Solution

A numerical controller that calculates and applies compensation amounts for linear and rotary axis-dependent translational and rotational errors, ensuring accurate positioning and orientation of the tool center point by adding translational and rotational compensation amounts to command positions, thereby correcting errors in both linear and rotary axes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If only linear axis position compensation is applied, then tool center point positioning accuracy is improved, but tool orientation accuracy deteriorates

Engineering Contradiction:

Improvetool center point positioning accuracyVSAvoidtool orientation accuracy

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The compensation system is segmented into two independent but coordinated components: translational compensation for tool center point positioning and rotational compensation for tool orientation. Each component processes specific error types (translational errors affect position, rotational errors affect orientation) and applies appropriate compensation calculations, allowing both positioning accuracy and orientation accuracy to be improved simultaneously without conflict.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If conventional single-axis compensation is used, then system complexity is reduced, but machining precision for side face machining and drilling deteriorates

Engineering Contradiction:

Improvecompensation system complexityVSAvoidmachining precision

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent merges translational compensation and rotational compensation into a unified five-axis error compensation system. The compensation amount calculating unit integrates both translational compensation amounts (for linear axes) and rotational compensation amounts (for rotary axes) into a single coordinated control mechanism. This combined approach maintains manageable system complexity while achieving high machining precision for operations requiring both accurate positioning and orientation, such as side face machining and drilling.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8283884B2Numerical controller controlling five-axis machining tool

Publication Date: 2012.10.09 FANUC LTD

AI summary

A five-axis machining tool that machines a workpiece mounted on a table using three linear axes and two rotary axes is controlled by a numerical controller. The numerical controller calculates a translational compensation amount and a rotational compensation amount by obtaining axis-dependent translational compensation amounts and axis-dependent rotational compensation amounts on the basis of commanded axis positions. Then, the numerical controller moves the three linear axes and the two rotary axes of the five-axis machining tool to positions obtained by adding the translational compensation amount and the rotational compensation amount thus calculated to a command linear axis position and a command rotary axis position, respectively.