Numerical Controller Five-Axis Error Compensation

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Solution Overview

Problem

Current five-axis machining technologies face challenges in accurately compensating for linear and rotary axis-dependent translational and rotational errors, limiting the precision of machining operations.

Innovation Solution

A numerical controller is developed to calculate and apply separate compensation amounts for linear and rotary axis-dependent rotational and translational errors, allowing for independent movement and precise positioning of axes in a five-axis machining apparatus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If comprehensive compensation for all four errors (linear axis-dependent translational, linear axis-dependent rotational, rotary axis-dependent translational, rotary axis-dependent rotational) is implemented, then machining precision is improved, but device complexity and data storage requirements increase

Engineering Contradiction:
Improvemachining precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the error compensation into four distinct components: linear axis-dependent translational error, linear axis-dependent rotational error, rotary axis-dependent translational error, and rotary axis-dependent rotational error. Each error type is measured, stored, and compensated independently through separate calibration procedures and data structures. This segmentation allows the complex compensation task to be divided into manageable parts that can be processed and stored efficiently

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements preliminary calibration procedures that measure and store compensation data for all four error types before actual machining operations. The calibration process pre-determines compensation values for linear axis positions and rotary axis positions, storing them in lookup tables. During machining, the controller simply retrieves pre-calculated compensation values based on current axis positions, avoiding complex real-time calculations and reducing control system complexity

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If comprehensive compensation data for all axis positions and error types is stored, then machining accuracy is improved, but memory capacity requirements increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidmemory capacity
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The compensation data is segmented by error type and axis dependency, with separate storage structures for linear axis-dependent errors and rotary axis-dependent errors. This segmentation allows the system to store only the necessary compensation parameters for each specific error source rather than redundant comprehensive data, optimizing memory utilization

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms complex error compensation requirements into simplified parameter storage by using lookup tables that map axis positions to pre-calculated compensation values. Instead of storing and processing complex error models, the system stores simplified parameter sets that can be quickly retrieved and applied, significantly reducing memory requirements while maintaining compensation accuracy

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2065771B1Numerical controller for controlling a five-axis machining apparatus
Publication Date: 2012.12.05 FANUC LTD
  • EP2065771B1 patent drawingFigure 1
  • EP2065771B1 patent drawingFigure 2
  • EP2065771B1 patent drawingFigure 3

AI summary

A numerical controller capable of moving a tool end point position to an accurate position in a five-axis machining apparatus. Compensation amounts are set, which correspond to respective ones of a linear axis-dependent translational error, a rotary axis-dependent translational error, a linear axis-dependent rotational error, and a rotary axis-dependent rotational error, which are produced in the five-axis machining apparatus. A translational/rotational compensation amount Δ3D is determined from these compensation amounts and added to a command linear axis position Pm. As the compensation amounts, there is used a corresponding one of six-dimensional lattice point compensation vectors, which are determined in advance as errors due to the use of a mechanical system and measured at lattice points of lattices into which the entire machine movable region is divided.