Machine Tool Controller Interference Compensation
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Solution Overview
Problem
Machine tools with feed and rotary control axes experience interference, leading to instability and reduced processing accuracy due to mechanical and dynamic effects, with existing solutions either increasing equipment costs or being unsuitable for high-speed, accurate positioning requirements.
Innovation Solution
A controller device that estimates and corrects interference between feed and rotary control axes in a machine tool by using position and mass information of an eccentric load, allowing for accurate motion control without the need for additional position detectors, and adapting to changes in load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a position detector is installed to measure actual displacement for eliminating error factors, then measurement precision is improved, but equipment costs increase and installation space requirements arise
Solution Approach 1:
The patent uses a reaction device that generates a force canceling the reaction force from the slider, creating a virtual copy of the disturbance rather than directly measuring it. This eliminates the need for physical position detectors while maintaining control accuracy through force balance
Solution Approach 2:
The patent replaces the mechanical position detection system with a reaction force-based control system. Instead of using sensors to detect position, the system uses the reaction force from the linear motor to control the stator's motion, substituting mechanical measurement with mechanical interaction
2Manufacturing precision
If feedback compensation is used to eliminate interference between control axes, then manufacturing precision is improved, but device complexity increases due to additional calculation and state observation means
Solution Approach 1:
The patent extracts the reaction force component from the overall system dynamics and handles it separately through a dedicated reaction device. By isolating and canceling the reaction force, the system simplifies the interference compensation without requiring complex multi-axis coordination calculations
Solution Approach 2:
The patent calculates and applies interference compensation in advance based on the commanded motion of the rotary control axis, rather than reacting to actual deviations. This preliminary compensation approach eliminates interference before it affects positioning accuracy, reducing the need for complex real-time feedback mechanisms
3Manufacturing precision
If state observation means is used to estimate interference torque and correct command values, then manufacturing precision is improved, but the solution is difficult to adapt to quick and accurate positioning control in machine tools
Solution Approach 1:
The patent replaces complex state observation and interference estimation algorithms with a direct reaction force measurement approach. By using the physical reaction force from the linear motor to drive the stator, the system achieves accurate interference compensation through mechanical feedback rather than computational estimation, enabling faster response
Solution Approach 2:
The reaction device uses the reaction force generated by the linear motor itself to control the stator's motion. The system serves itself by utilizing its own byproduct (reaction force) as the control input, eliminating the need for external sensors or complex estimation algorithms while maintaining high-speed performance
Data Source
AI summary
A device for controlling a feed motion of a feed control axis and a rotary motion of a rotary control axis, both axes being provided in a machine tool so that the rotary control axis is fed along the feed control axis. The device includes an interference estimating section estimating an interference generated between the feed control axis and the rotary control axis, based on a position command instructed to at least one of the feed control axis and the rotary control axis and a position and mass information of an eccentric load carried by the rotary control axis; and a command correcting section correcting a current command given to at least one of the feed control axis and the rotary control axis, based on the interference estimated by the interference estimating section.