Machine Tool Spindle Drive Force Measurement via Phase Synchronization

Solution Overview

Problem

Conventional machine tools require extremely short sampling cycles to measure phenomena like drive force changes on rotary shafts, leading to increased costs and complexity in measurement and analysis.

Innovation Solution

A machine tool with a rotary shaft device and a control device that synchronizes sensor data acquisition with rotation, determining steady-state machining conditions to perform measurements with a predetermined sampling cycle, associating data with rotation phases and calculating changes over multiple rotations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If extremely short sampling cycle is used to measure high-speed phenomena on rotary shaft, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvemeasurement precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The control device determines steady-state conditions in advance before performing measurements. By pre-judging whether the rotary shaft is in a steady state based on command values, the system prepares measurement conditions optimally, avoiding the need for continuous high-speed sampling while ensuring accurate measurements are taken only when necessary and appropriate.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sampling cycle is dynamically adjusted based on the steady-state determination. When steady-state is detected, measurements are performed with adequate precision; when non-steady-state, measurements are skipped or performed less frequently. This parameter change in sampling strategy resolves the contradiction by adapting measurement intensity to actual measurement needs.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If extremely short sampling cycle is used to measure high-speed phenomena on rotary shaft, then measurement precision is improved, but cost increases

Engineering Contradiction:

Improvemeasurement precisionVSAvoidcost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The control device determines steady-state conditions in advance before performing measurements. By pre-judging whether the rotary shaft is in a steady state based on command values, the system prepares measurement conditions optimally, avoiding the need for continuous high-speed sampling while ensuring accurate measurements are taken only when necessary and appropriate.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sampling cycle is dynamically adjusted based on the steady-state determination. When steady-state is detected, measurements are performed with adequate precision; when non-steady-state, measurements are skipped or performed less frequently. This parameter change in sampling strategy resolves the contradiction by adapting measurement intensity to actual measurement needs.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If measurement is performed during non-steady-state machining, then productivity is improved, but measurement precision deteriorates

Engineering Contradiction:

ImproveproductivityVSAvoidmeasurement precision

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The control device determines steady-state conditions in advance before performing measurements. By pre-judging whether the rotary shaft is in a steady state based on command values, the system prepares measurement conditions optimally, avoiding the need for continuous high-speed sampling while ensuring accurate measurements are taken only when necessary and appropriate.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sampling cycle is dynamically adjusted based on the steady-state determination. When steady-state is detected, measurements are performed with adequate precision; when non-steady-state, measurements are skipped or performed less frequently. This parameter change in sampling strategy resolves the contradiction by adapting measurement intensity to actual measurement needs.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10265818B2Machine tool

Publication Date: 2019.04.23 OKUMA CORP

AI summary

In a machine tool, when machining is in a steady zone, a rotation phase of a main spindle at the time of measurement in the N-th sampling is calculated, and the calculated rotation phase and the measurement value are recorded in a recording section so as to be associated with each other. The measurement and calculation of the rotation phase of the main spindle at the time of each measurement are continued for plural times of rotations of the main spindle, and thus the measurement values are obtained at various rotation phases, whereby change in drive force during one rotation of the main spindle is finally calculated.