Encoder Detection Period Switching for Position Delay
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Solution Overview
Problem
Absolute encoders face delays in position detection due to the time required for signal stabilization after switching detection periods, leading to complex configurations and potential position detection errors.
Innovation Solution
An encoder design that switches detection periods between multiple periodic patterns, using a controller to manage the position detection process and minimize delays by maintaining consistent detection periods across processes, thereby reducing the need for immediate signal stabilization and enhancing detection speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple periodic patterns with different periods are provided in the scale and detection period switching is implemented, then the number of detectors is reduced, but delay in position detection occurs due to signal stabilization time after switching
Solution Approach 1:
The patent applies preliminary action by maintaining a buffer of previously detected position data before switching detection periods. When switching occurs, the system uses the buffered historical data to immediately determine position without waiting for the new detection period to stabilize, thereby eliminating detection delay while reducing the number of detectors needed.
2Device complexity
If multiple periodic patterns are used to reduce detectors, then configuration is simplified, but measurement precision may be affected due to signal stabilization delays
Solution Approach 1:
The system pre-buffers position detection data before switching detection periods. This buffered data serves as a foundation for immediate position determination after switching, ensuring measurement precision is maintained without requiring multiple detectors or waiting for signal stabilization.
Solution Approach 2:
The patent implements feedback mechanisms where the controller continuously monitors detection period transitions and adjusts positioning calculations based on buffered historical data. This feedback ensures that position measurements remain accurate even when detection periods are switched, maintaining measurement precision while simplifying the detector configuration.
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
This approach allows for rapid and accurate position detection without waiting for signal stabilization, reducing errors and simplifying the encoder configuration by maintaining consistent detection periods across processes.
Implementation Method 1
a sensor outputting a periodic signal that periodically changes corresponding to the periodic pattern with relative movement of the sensor and the scale
Data Source
Figure 1~2
Figure 3(A)~4
Figure 5~6
AI summary
The encoder includes a scale (10) including first and second periodic patterns (11, 12), and a detector (22) relatively movable with respect to the scale and whose detection state is switchable between a first detection state to read the first periodic pattern and output a first signal and a second detection state to read the second periodic pattern and output a second signal. A processor (40) performs a first process to detect a first absolute position by using the first and second signals and then performs a second process to calculate a relative movement amount by using a specific signal that is one of the first and second signals and detect a second absolute position by using the relative movement amount and the first absolute position. The specific signal is obtained from the detector set in a same detection state as that set last in the first process.