Machine Tool Thermal Displacement Compensation via Adaptive Time-Dispersion
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Solution Overview
Problem
Machine tools experience thermal displacement errors due to heat-generated deformations, leading to processing inaccuracies and increased warming-up times to minimize these errors, which prolong processing times.
Innovation Solution
An apparatus and method that calculate a compensation quantity using temperature data and a predetermined parameter, applying exponential smoothing and time-dispersion compensation, with an adaptive time-dispersion period adjustment based on error thresholds to rapidly follow actual thermal displacement without requiring long warming-up times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If exponential smoothing and time-dispersion compensation are applied to compensate thermal displacement, then manufacturing precision is improved, but loss of time increases due to required warming-up time
Solution Approach 1:
The patent applies dynamic adjustment of the time-dispersion compensating period based on real-time error absolute values. When error exceeds threshold, the period is shortened to accelerate response; when error is within threshold, normal period is maintained. This dynamic adaptation eliminates fixed warming-up time requirements while maintaining compensation accuracy.
Solution Approach 2:
The patent implements feedback control by continuously calculating error absolute values between input and output of the time-dispersion compensating unit, comparing them against thresholds, and adjusting the compensating period accordingly. This closed-loop feedback mechanism enables the system to automatically adapt to thermal displacement changes without prolonged warming-up.
2Productivity
If the time-dispersion compensating period is shortened to rapidly follow actual displacement, then productivity is improved, but manufacturing precision deteriorates due to insufficient compensation accuracy
Solution Approach 1:
The system dynamically adjusts the time-dispersion compensating period based on error magnitude. During rapid thermal changes, the period shortens to improve tracking speed. During stable conditions, the period returns to normal to maintain compensation accuracy. This dynamic balancing resolves the trade-off between speed and precision.
Solution Approach 2:
The patent changes the time-dispersion compensating period parameter adaptively based on error absolute values and thresholds. By modifying this critical parameter in response to system state, the patent achieves both rapid response during thermal transients and accurate compensation during steady-state operation.
Data Source
AI summary
Disclosed are a method and an apparatus for compensating thermal displacement of a machine tool, the apparatus including: a compensation quantity calculating unit configured to calculate a compensation quantity by using temperature data and a predetermined compensation parameter; a smoothing filter configured to exponentially smooth the calculated compensation quantity; a scaling unit configured to scale the exponentially smoothed compensation quantity; a time-dispersion compensating unit configured to calculate a final compensation quantity by time-dispersion compensation for the scaled compensation quantity according to a time-dispersion compensating period; and a control unit configured to compensate each axis of equipment according to the final compensation quantity, and adjusts the time-dispersion compensating period of the time-dispersion compensating unit according to an error absolute value representing a difference between an input value and an output value of the time-dispersion compensating unit.