Machine Tool Oscillation Control Device for Stop Position Accuracy
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Solution Overview
Problem
Existing machine tool control systems fail to accurately control the cutting tool's oscillation amplitude near the machining stop position, leading to potential tool overextension and cuts beyond the intended stop position, especially when learning control is applied.
Innovation Solution
A control device for a machine tool that includes a position command generation part, an oscillation command generation part, a normalization part, a learning control part, and a denormalization part, which together generate and adjust the oscillation commands to ensure compliance with the machining stop position by normalizing and denormalizing the resultant commands based on the oscillation phase and position commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If learning control is applied to oscillation cutting, then control precision is improved, but compliance response speed deteriorates causing the tool to exceed the machining stop position
Solution Approach 1:
The control system is segmented into distinct functional blocks: oscillation command generation part, normalization part, learning control part, and denormalization part. Each block performs a specific function, allowing the complex learning control process to be divided into manageable stages that can be optimized independently while maintaining overall system precision and responsiveness.
Solution Approach 2:
The normalization part performs preliminary processing on the oscillation command before it enters the learning control part. By normalizing the command in advance, the system prepares the data in an optimal format for learning control processing, enabling faster and more accurate compliance response when the tool approaches the machining stop position.
2Manufacturing precision
If oscillation amplitude is decreased near the machining stop position, then tool overextension is prevented, but compliance diminishes causing the tool to still exceed the stop position
Solution Approach 1:
The oscillation amplitude is made dynamic rather than fixed. The system continuously adjusts the oscillation amplitude based on the tool's proximity to the machining stop position, increasing amplitude when far from the stop position to maintain compliance, and decreasing amplitude near the stop position to prevent overextension, thereby achieving both compliance and precision.
Solution Approach 2:
The denormalization part provides feedback by converting the normalized learning control output back into the original oscillation command scale. This feedback mechanism ensures that the learning control corrections are applied appropriately, maintaining compliance while preventing tool overextension at the machining stop position.
3Ease of operation
If normalization and denormalization are applied in the learning control part, then compliance is improved, but device complexity increases
Solution Approach 1:
The normalization and denormalization parts serve multiple functions: they prepare data for learning control processing, enable the learning control part to operate with standardized inputs, and convert the corrected commands back to the original scale for execution. This multi-functionality justifies the added components by providing comprehensive benefits that improve overall system compliance.
Data Source
AI summary
A control device for a machine tool includes an oscillation command generation part which generates an oscillation command for a fees axis, a first adding part which adds an oscillation command to a position deviation between a position command and the detected position of the fees axis to generate a resultant command, a normalization part for normalizing the resultant command, a learning control part that obtains a correction amount of the resultant command based on an oscillation phase obtained from the oscillation command and a normalized resultant command and which adds the correction amount to the resultant command, a denormalization part which denormalizes an output from the learning control part, and a second adding part for adding a denormalized output from the denormalization part to the resultant command.