Rotary Axis Alignment Feedback for Machine Tool Position Correction

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Solution Overview

Problem

Machine tools face challenges in maintaining high positioning accuracy during operation due to deviations in the orientation and position of the axis of rotation, which affect the precision of machining processes.

Innovation Solution

A device comprising a measuring device, a control device, and an actuator that measures the relative position between a tool holder and a workpiece holder in multiple dimensions, allowing for real-time correction of orientation and position deviations using actuators that can adjust the axis of rotation, thereby improving machining precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If angle measuring devices are used to measure rotational movements, then the measurement capability is improved, but the positioning accuracy during operation deteriorates due to axis orientation deviations

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidpositioning accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

A measuring device with first and second component groups is introduced as an intermediary system. The first component group attaches to the stationary structure while the second component group attaches to the rotatable component. This intermediary measuring system captures actual axis orientation and translational position under operating load, enabling correction of positioning accuracy without altering the fundamental rotational measurement capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The measuring device provides feedback signals about the actual orientation and position of the axis of rotation under operating load. This feedback is used to correct positioning accuracy by compensating for deviations between the ideal axis orientation and the actual axis orientation during machining operations

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the axis of rotation is allowed to deviate under operating load, then the measurement of actual position is improved, but the positioning accuracy deteriorates

Engineering Contradiction:
Improveactual position measurementVSAvoidpositioning accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The measuring device is pre-installed with component groups on both the stationary structure and the rotatable component. This preliminary setup enables the system to measure actual axis orientation and translational position before machining operations begin, allowing for pre-correction or real-time compensation during operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors actual axis orientation and translational position under operating load and uses this feedback information to correct positioning accuracy. The control system adjusts the positioning based on measured deviations, maintaining manufacturing precision despite axis orientation changes under load

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If actuators are added to correct axis orientation, then positioning accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The measuring device serves multiple functions: it measures rotational movements, measures actual axis orientation under load, measures translational position of the axis, and provides feedback for correction. This multi-functionality reduces the need for separate measurement and correction systems, offsetting the complexity added by actuators

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own measuring capabilities to identify positioning deviations and triggers corrective actions through actuators. The measuring device and control system work together in a self-correcting loop, reducing the need for external intervention or additional complex control mechanisms

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4119288B1Device for correcting positional deviations of a processing machine
Publication Date: 2023.10.04 DR JOHANNES HEIDENHAIN GMBH
  • EP4119288B1 patent drawingFigure 1~2
  • EP4119288B1 patent drawingFigure 3~4
  • EP4119288B1 patent drawingFigure 5~6

AI summary

The invention relates to a device comprising a measuring device (1), a control device (2), an actuator (3), and a controller (4), wherein the measuring device (1) comprises a first component group (1.1) and a second component group (1.2). The first component group (1.1) and the second component group (1.2) are rotatable relative to each other about a rotational axis (A). The measuring device (1) enables the measurement of the relative position between the first component group (1.1) and the second component group (1.2) in several dimensions. Furthermore, the measuring device (1) can generate first signals (S1) containing information about the actual orientation of the rotational axis (A) relative to a first directional axis (x), and second signals (S2) containing information about the actual position of the first component group (1.1) relative to the second component group (1.2).2) in the first directional axis (x) and/or a second directional axis (y) and/or a third directional axis (z). By actuating the actuator (3), the orientation of the rotary axis (A) relative to the first component group (1.1) can be changed. Depending on the information about the actual orientation of the rotary axis (A), it can be brought into a target orientation with the aid of the actuator (3). Furthermore, the measuring device (1) is connected to the control unit (4) for transmitting the second signals (S2) for correcting the relative position between a tool holder (T) and a workpiece holder (W). (Figure 2).