Encoder Self-Calibration via Template Matching
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Solution Overview
Problem
Existing encoder calibration methods require separate, highly accurate encoders, making the process time-consuming and difficult to achieve high accuracy.
Innovation Solution
An encoder design that includes a base portion, a scale portion with movable or rotatable marks, an imaging element, and an estimation portion performing template matching to detect mark positions and estimate movement or rotation states, allowing for accurate calibration without a separate calibration encoder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate highly accurate encoder is used for calibration, then calibration accuracy is improved, but calibration time increases and the process becomes more complex
Solution Approach 1:
The encoder performs calibration using its own imaging element and processing unit, without requiring a separate calibration encoder. The imaging element captures images of marks on the scale portion, and the processing unit calculates pixel numbers and performs calibration computations internally, enabling the system to calibrate itself autonomously
Solution Approach 2:
The patent extracts the calibration function from the separate calibration encoder and integrates it into the main encoder system. By removing the dependency on an external calibration device and implementing calibration capabilities within the encoder itself, the system eliminates the need for additional equipment while maintaining calibration accuracy
2Measurement precision
If a separate highly accurate encoder is used for calibration, then calibration accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the calibration functionality into the main encoder by integrating the imaging element and processing unit within the same device. This consolidation eliminates the need for separate calibration equipment and simplifies the overall system architecture while maintaining calibration capabilities
Solution Approach 2:
The imaging element and processing unit serve multiple functions: they are used for both normal operation (detecting scale portion position) and calibration operations. This multi-functionality reduces the need for dedicated calibration components and simplifies the device structure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables highly accurate calibration of the encoder and its application in robots and printers, simplifying the calibration process and reducing the need for pre-measured relative positions of marks.
Implementation Method 1
an imaging element that is disposed in the base portion, and images the marks
Implementation Method 2
an estimation portion that performs template matching on a captured image in the imaging element by using a reference image, so as to detect positions of the marks
Data Source
AI summary
An encoder includes a base portion, a scale portion that is provided to be relatively rotatable with respect to the base portion, and has a plurality of marks, an imaging element that is disposed in the base portion, and images the marks, and an estimation portion that performs template matching on a captured image in the imaging element by using a reference image, in which the plurality of marks include a first mark and a second mark, and the estimation portion counts the number of pixels of the imaging element corresponding to a rotation angle of the scale portion with respect to the base portion until a position of the second mark is detected from detection of a position of the first mark, and performs calibration on the basis of the counted number of pixels and the rotation angle.