Rotation Detection Apparatus Error Correction
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Solution Overview
Problem
Existing rotation detection apparatuses for motors face accuracy issues due to arrangement errors in pattern element portions, leading to degraded detection resolution and inability to detect minute oscillations in rotational speed.
Innovation Solution
A rotation detection apparatus that includes a rotatable member with pattern element portions, a signal outputter, memory for correction values, and a corrector that uses these values to correct errors in detection signals caused by arrangement errors, allowing for accurate rotation detection and motor control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction values are stored for each pattern element portion to improve detection accuracy, then measurement precision is improved, but device complexity increases due to larger memory requirements
Solution Approach 1:
The correction values are segmented and stored in a structured manner in the memory, with each correction value corresponding to a specific pattern element portion. This segmentation allows the system to manage and access correction data efficiently without overwhelming complexity, while still achieving high measurement precision through individual correction of each pattern element's position error.
2Measurement precision
If correction is performed for each change of detection signal, then measurement precision is improved, but processing time increases
Solution Approach 1:
The correction values are pre-calculated and stored in the memory during the manufacturing or setup phase. When the rotary encoder operates, the controller simply retrieves the appropriate correction value from memory based on the detected pattern element position and applies it to correct the detection signal. This preliminary preparation eliminates complex real-time calculations, thereby improving measurement precision without significantly increasing processing time during operation.
3Measurement precision
If arrangement error is corrected to improve detection accuracy, then manufacturing precision requirements are relaxed, but device complexity increases
Solution Approach 1:
Instead of attempting to eliminate arrangement errors through stringent manufacturing controls, the invention measures the actual arrangement errors during setup, calculates correction values for each pattern element portion, and stores these in memory. The system then applies these correction values to compensate for the manufacturing errors, effectively converting the harmful arrangement errors into correctable data points. This approach relaxes manufacturing precision requirements while adding a software-based correction layer.
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 high-accuracy detection of motor rotation and speed, improving detection resolution and enabling precise motor control by correcting errors in the detection signals.
Implementation Method 1
a sensor that magnetically or optically detects a pattern for rotation detection (rotation detection pattern) provided to the rotatable member
Implementation Method 2
a sensor that magnetically or optically detects a pattern for rotation detection (rotation detection pattern) provided to the rotatable member
Data Source
AI summary
The rotation detection apparatus includes a rotatable member rotatable with rotation of a motor and having multiple pattern element portions in its rotational direction, a signal outputter to output a detection signal changing in response to rotation of the pattern element portions, and a memory storing correction values each provided for each of the pattern element portions and used to perform correction of an error in a relation between rotational positions of the rotatable member and the change of the detection signal. A corrector performs the correction with reference to a reference position of the rotatable member in an origin state where a driven member driven by the motor is located at its origin position and by using each of the correction values for each change of the detection signal when the rotatable member is rotated from the reference position.