Spindle Axis Controller for Synchronized Tapping

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Solution Overview

Problem

Current machine tool control systems require complex parameter settings and adjustments to maximize spindle axis acceleration capacity, leading to increased cycle time and mechanical or structural shocks during tapping processes.

Innovation Solution

A controller configured to control synchronized operations of spindle and feed axes, which includes a numerical control section to prepare spindle-axis and feed-axis commands, and control sections for rotational motion, position detection, and torque command limiting, allowing for accelerated and decelerated rotations based on detected positions and speeds, thereby maximizing acceleration capacity without complex parameter settings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If complex parameter settings and adjustments are performed to maximize spindle axis acceleration capacity, then productivity is improved, but device complexity increases

Engineering Contradiction:

Improvecycle timeVSAvoidparameter setting complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The control system automatically detects the power characteristics of the spindle axis and generates acceleration/deceleration commands without requiring manual parameter settings. The numerical control unit performs self-testing to identify motor constants and uses this information to optimize the acceleration capacity automatically, eliminating the need for operator intervention in parameter adjustment

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system dynamically adjusts acceleration and deceleration parameters based on the detected power characteristics of the spindle axis. By changing control parameters automatically according to the measured motor constants and load conditions, the system maximizes acceleration capacity without requiring manual parameter optimization

Inventive Principle:

Principle #35Parameter changes

2Productivity

If acceleration and deceleration commands are prepared in conformity with power characteristics, then productivity is improved, but ease of operation deteriorates

Engineering Contradiction:

Improveresponse of spindle axisVSAvoidoperation simplicity

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #25Self-service

3Productivity

If the spindle axis operates at maximum acceleration capacity, then productivity is improved, but mechanical shock increases

Engineering Contradiction:

Improveacceleration capacityVSAvoidmechanical shock

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The control system uses feedback from the detected rotational position and power characteristics to continuously optimize the acceleration and deceleration commands. This closed-loop control ensures that the spindle axis operates at maximum capacity while maintaining smooth transitions that minimize mechanical shock

Inventive Principle:

Principle #23Feedback

4Productivity

If the spindle axis operates at maximum acceleration capacity, then productivity is improved, but synchronization error increases

Engineering Contradiction:

Improveacceleration capacityVSAvoidsynchronization accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10209697B2Device and method of controlling machine tool, to control synchronized operation of spindle axis and feed axis

Publication Date: 2019.02.19 FANUC LTD

AI summary

A controller for controlling a synchronized operation of spindle and feed axes. A spindle-axis control section includes an initial-motion control section for accelerating a spindle axis from a starting position; a maximum-acceleration detecting section for detecting a maximum acceleration of the spindle axis during acceleration; a residual rotation-amount detecting section for detecting a residual rotation amount of the spindle axis; a current-speed detecting section for detecting a current speed of the spindle axis; a decelerating-motion control section for decelerating the spindle axis to reach an intermediate speed, after the acceleration; a positioning-motion control section for decelerating the spindle axis to reach the target position after reaching the intermediate speed; and a torque-command limiting section for limiting a fluctuation of a torque command of the position control, instructed to the spindle axis, to a predetermined range over a period until a predetermined elapse condition is satisfied after reaching the intermediate speed.