Absolute Encoder Startup Offset Correction for Angle Deviation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Absolute encoders suffer from angle deviations due to manufacturing variations, leading to a maximum angle deviation that varies with the start position, affecting accuracy.
Innovation Solution
An absolute encoder system that includes a sensor generating a signal based on a rotating body's rotation, a computer determining an offset value using a coefficient to correct angle deviations, and a microcomputer implementing this correction to minimize maximum angle deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the absolute encoder uses the start position as the zero point reference, then the encoder can detect position from the reference, but the maximum angle deviation varies depending on the start position
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction values for all possible start positions before actual operation. The microcomputer calculates the angle deviation waveform in advance for each potential start position and determines the optimal correction value that minimizes maximum deviation. This pre-computed correction data is then applied during operation based on the detected start position, ensuring consistent accuracy without real-time computation overhead.
Solution Approach 2:
The patent changes the parameter being corrected from a fixed zero-point offset to a variable correction value that depends on the start position. By calculating and applying different correction values based on the detected start position, the system adapts the angle deviation correction to match the specific operational conditions, thereby minimizing the maximum angle deviation regardless of where the encoder starts.
2Device complexity
If the encoder corrects angle deviation using a fixed offset value, then the correction process is simple, but the maximum angle deviation cannot be suppressed across different start positions
Solution Approach 1:
The patent resolves this contradiction by performing the complex calculation work in advance. The microcomputer calculates angle deviation waveforms and determines optimal correction values for all possible start positions during initialization or setup. This pre-computation stores the results in memory, allowing the operational phase to simply retrieve and apply the appropriate correction value based on the detected start position, thus maintaining operational simplicity while achieving high precision.
Solution Approach 2:
The system performs self-service by automatically detecting the start position and selecting the appropriate pre-calculated correction value without requiring external intervention or complex real-time computation. The microcomputer autonomously identifies the start position, retrieves the corresponding correction data, and applies it to minimize angle deviation, making the system self-adjusting and maintaining simplicity in operation.
Data Source
AI summary
To suppress a maximum value of an angle deviation regardless of the position of a rotating body at the time of start-up. An absolute encoder includes a sensor configured to generate a signal indicating a value of a predetermined physical quantity varying depending on a rotation of a rotating body, a computer configured to generate angle information indicating an angle of the rotating body on the basis of the signal the computer determines an offset value for correcting an angle deviation indicating a difference between an angle indicated by the angle information and an actual angle of the rotating body to reduce the angle deviation, on the basis of the angle information at the time of start-up and a predetermined coefficient, and the computer corrects the angle deviation by using the offset value. The coefficient is calculated on the basis of the angle deviation.