Dynamic Feedforward Gain Controller for Route Error Reduction

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Solution Overview

Problem

Existing control systems for coordinate measuring machines and machine tools fail to sufficiently reduce route errors during high-speed movement due to constant compensator values that do not adapt to changing response characteristics of moving axes.

Innovation Solution

A controller method that includes a position commander and an error corrector with a feedforward controller and a compensator calculator, which calculates a feedforward gain based on the position command value to perform feedforward control, reducing route errors by adapting to moving speed, radius, and frequency of circular motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a constant compensator value is used in the feedforward control system, then the control system is simple and stable, but the route error cannot be sufficiently reduced during high-speed movement because the compensator cannot follow the change of response characteristics

Engineering Contradiction:
Improveroute error reductionVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the compensator value variable instead of constant. The compensator is dynamically adjusted based on the moving speed of the moving mechanism, allowing it to adapt to changing response characteristics during high-speed movement and effectively reduce route errors while maintaining system stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of the compensator from a fixed constant value to a variable value that depends on the moving speed. By calculating and adjusting the compensator value according to the actual moving speed, the system achieves better route error reduction performance without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the moving speed of the moving mechanism is increased to improve productivity, then the processing efficiency is improved, but the response characteristics of the moving axes change causing increased route error

Engineering Contradiction:
Improvemoving speedVSAvoidroute error
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements feedback by using the actual moving speed information to adjust the compensator value. The system continuously monitors the moving speed and dynamically modifies the compensator accordingly, creating a closed-loop control mechanism that maintains precision even at high speeds.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent makes the control system dynamic by adapting the compensator value to the current moving speed. This dynamic adjustment allows the system to maintain optimal performance across different speed ranges, enabling high-speed operation without sacrificing accuracy.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2131255B1Controller
Publication Date: 2014.05.07 MITUTOYO CORP
  • EP2131255B1 patent drawingFigure 1
  • EP2131255B1 patent drawingFigure 2A~2B
  • EP2131255B1 patent drawingFigure 3

AI summary

The controller (1) includes a position commander (3) and an error corrector (5). The position commander (3) outputs a position command value for moving a moving mechanism (2). The error corrector (5) includes a feedforward controller (51) and a compensator calculator (52). The feedforward controller (51) performs a feedforward control of the moving mechanism (2) based on the position command value outputted from the position commander (3) and includes a gain (512). The compensator calculator (52) calculates a value to be set as the gain (512) of the feedforward controller (51) based on the position command value outputted from the position commander (3) and the average value of the route error.