Machine Tool Axis Drive Control for Constant Contact Force
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Solution Overview
Problem
Existing methods for controlling axle drive trains in machine tools, particularly for machining wood or wood-based materials, struggle to maintain a constant pressing force during machining, leading to quality losses due to deviations between setpoint and actual values caused by disturbance variables, especially on non-periodic movement paths.
Innovation Solution
A method that determines reference variables at positions of the axle drive train and corrects them using position-independent and position-dependent correction values, which include inertial and frictional forces, allowing for advanced compensation of disturbance variables, thereby ensuring high machining quality across any movement path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a classical feedback control system is used to maintain constant contact force, then the control system can respond to deviations, but machining quality deteriorates due to time delay and inability to compensate for disturbances in advance
Solution Approach 1:
The patent applies preliminary action by determining correction values in advance based on position information before the actual machining operation. The control system pre-calculates the necessary corrections for contact force deviations at different positions, allowing these corrections to be applied proactively rather than reactively. This eliminates the time delay inherent in feedback control systems and ensures machining quality is maintained throughout the operation.
2Measurement precision
If disturbance compensation is implemented for periodic motion paths, then control accuracy improves, but the system cannot handle non-periodically recurring motion paths
Solution Approach 1:
The patent applies parameter changes by transitioning from fixed periodic compensation parameters to dynamically adaptable parameters based on actual position information. The system determines correction values specific to each position along the motion path, allowing it to handle both periodic and non-periodic motion paths effectively. This position-specific parameter adaptation enables universal applicability across different motion patterns while maintaining high control accuracy.
3Manufacturing precision
If comprehensive disturbance compensation is implemented for all motion paths, then machining quality improves, but storage requirements and system complexity increase
Solution Approach 1:
The patent applies local quality by implementing position-specific correction values rather than universal compensation parameters. Each position along the axis drive train's path has its own tailored correction value determined based on local disturbance characteristics. This localized approach maintains high machining quality while reducing overall system complexity compared to implementing comprehensive compensation for all possible positions and conditions.
Data Source
Figure 1~3
AI summary
A method for controlling an axle drive train of a machine tool for machining a workpiece, which preferably consists at least in sections of wood, wood-based materials, plastic or the like, comprising determining reference variables at positions of an axle of the axle drive train and correcting the reference variables at these positions Correction values that were determined by means of performance indicators of a drive device at these positions, which are set when the axis of the axle drive train is accelerated by the drive device without load to a constant speed and is moved along these positions at this constant speed, as well as a device with a controller for execution provided by this procedure.