Actively Compensated Stage for 5-DOF Motion Error Correction
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Solution Overview
Problem
Existing carrying stages for machining apparatuses face challenges in compensating for 5-DOF motion errors, which can lead to machining inaccuracies due to surface errors in the guide support, and existing solutions are inadequate for comprehensive error compensation.
Innovation Solution
An actively compensated stage equipped with linear encoders, control units, magnetic actuators, and accelerometers that calculate and apply control currents to compensate for 5-DOF motion errors and damping control for vibration errors, using feedback and feedforward control mechanisms to adjust magnetic forces and dampen vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If passive compensation methods (mechanical structures, gravity, thermal expansion) are used, then device complexity is reduced, but manufacturing precision deteriorates due to inability to actively correct motion errors
Solution Approach 1:
The patent replaces passive mechanical compensation structures with an active control system that uses sensors to detect motion errors and actuators to compensate for them in real-time. This substitution of mechanical systems with sensor-actuator control systems enables precise 5-DOF motion error compensation while maintaining manageable device complexity through software-based control algorithms.
Solution Approach 2:
The patent implements feedback control by using sensors to continuously monitor the actual motion of the movable platform, comparing it with the commanded motion, and generating correction signals to actuators. This closed-loop feedback mechanism enables real-time detection and compensation of motion errors across all five degrees of freedom, significantly improving manufacturing precision.
2Manufacturing precision
If 5-DOF active compensation is implemented, then manufacturing precision is improved, but device complexity increases due to multiple sensors and actuators
Solution Approach 1:
The patent employs a modular sensor-actuator architecture where each sensor-actuator pair is designed to be multi-functional, capable of compensating for errors in multiple degrees of freedom. This universal design reduces the total number of components needed while maintaining comprehensive 5-DOF compensation coverage, thereby improving precision without proportionally increasing device complexity.
Solution Approach 2:
The patent divides the 5-DOF compensation system into separate modules, each responsible for specific degrees of freedom or specific types of errors. This segmentation allows for independent optimization, easier troubleshooting, and modular replacement of components, managing overall system complexity while achieving high precision through coordinated operation of multiple specialized modules.
3Manufacturing precision
If real-time motion error compensation is performed, then manufacturing precision is improved, but use of energy increases due to continuous sensor and actuator operation
Solution Approach 1:
The patent implements periodic sampling of motion errors by sensors rather than truly continuous measurement, and updates compensation actions at optimized intervals. This periodic operation mode maintains manufacturing precision by sampling at frequencies sufficient to capture motion errors while significantly reducing energy consumption compared to truly continuous operation of all sensors and actuators.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively compensates for 5-DOF motion errors and improves accuracy by reducing machining inaccuracies, while also simplifying the structure and reducing costs, enhancing the precision and reliability of the machining process.
Implementation Method 1
An air bearing is disposed between the guide support and the table and allows the table to move above the guide support by forming an air layer between the guide support and the table
Implementation Method 2
A technology of compensating for a motion error by generating a magnetic force between the table and the guide support has been proposed
Implementation Method 3
accelerometers disposed at the table and detecting vibration signals of the table
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Disclosed are an actively compensated stage including: a guide support having first and second guide surfaces perpendicular to each other; a table having first and second sides opposite the first and second guide surfaces and having air bearings on the first and second sides; a driving linear motor moving the table straight in an x-axial direction; and a plurality of magnetic actuators applying a magnetic preload between the guide support and the table and changing a magnetic force between the guide support and the table to compensate for 5-DOF motion errors generated in the table.