Machining Device Encoder Signal Correction via Pre-calculated Lookup Tables
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Solution Overview
Problem
In digital printing methods, synchronizing the start and internal raster of the print image with web transport in machine tools is challenging due to speed-dependent and acceleration-dependent errors caused by dead times and noise in encoder signals, requiring complex signal processing and filtering.
Innovation Solution
Transmitting additional variables like speed, acceleration, and jerk via a non-real-time communication link, such as Ethernet, alongside the encoder signal, allows for more accurate position evaluation and correction, reducing the need for noise-prone differentiation and filtering, and enabling simpler encoder systems with lower incremental resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If encoder signals are transmitted through filtering and differentiation to reduce noise and improve accuracy, then measurement precision improves, but device complexity and processing time increase
Solution Approach 1:
The patent applies preliminary action by pre-calculating position values using a lookup table that stores predetermined position values corresponding to different encoder signals. This avoids the need for complex real-time filtering and differentiation operations, thereby maintaining measurement precision while reducing device complexity and processing requirements.
2Measurement precision
If complex filtering and multiple evaluation methods are applied to encoder signals, then measurement precision improves, but processing time increases
Solution Approach 1:
Position values are pre-calculated and stored in a lookup table during system initialization or operation. When an encoder signal is received, the system simply retrieves the corresponding pre-calculated position value from the table, eliminating the need for time-consuming real-time filtering, differentiation, and multiple evaluation operations while maintaining high position evaluation accuracy.
3Manufacturing precision
If high-resolution encoders are used to reduce speed-dependent errors, then manufacturing precision improves, but device complexity and cost increase
Solution Approach 1:
The patent changes the parameter of position calculation from direct encoder signal reading to retrieved values from a lookup table. This allows the system to achieve high position control accuracy without requiring high-resolution encoders, as the lookup table compensates for speed-dependent errors and provides corrected position values regardless of encoder resolution.
Data Source
AI summary
A method is disclosed for controlling at least one machining device which is coupled to a machine tool by means of an encoder signal, the machine tool having at least one motion control device. In order to improve the accuracy of the encoder connection, at least one additional variable which characterizes the transport is digitally transmitted from the motion control device to the at least one machining device and is used to correct the encoder signal.