Rotary Encoder Angle Detection Using Marking Section Exclusion
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Solution Overview
Problem
Existing rotary encoder systems for detecting the angle of rotation of a motor shaft require multiple sensors and a high design effort, and they often suffer from long initialization times, especially when the tooth gap needs to be aligned with a sensor, which can take almost a complete revolution.
Innovation Solution
A method using a marking carrier with sensor-readable markings, where a computing unit processes sensor signals to associate time profiles with marking sections, allowing for the exclusion of irrelevant markings and determining the angle of rotation without scanning the entire marking carrier, thereby reducing the time required for detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotary encoder with multiple sensors is used to detect the angle of rotation, then measurement precision is improved, but device complexity and manufacturing effort increase
Solution Approach 1:
The marking carrier is divided into multiple marking sections (e.g., teeth and tooth gaps in a gear wheel), each representing a specific angular position. The sensor sequentially scans these segments as the marking carrier rotates, enabling angle detection without requiring multiple sensors simultaneously. This segmentation allows the system to achieve precise angular measurement while using a single sensor, thus reducing device complexity.
2Device complexity
If a gear wheel with tooth gaps is used for angle detection, then device complexity is reduced, but initialization time increases due to the need to align the tooth gap with the sensor
Solution Approach 1:
The marking carrier is designed with multiple marking sections distributed around the rotation circle, including tooth gaps that can be detected by the sensor. The system performs preliminary scanning of these marking sections during normal operation to establish the current angular position without requiring a separate initialization alignment process. This allows the system to quickly determine the angle of rotation from any starting position, significantly reducing initialization time.
3Measurement precision
If the entire marking carrier is scanned to determine the angle of rotation, then measurement precision is ensured, but detection time increases
Solution Approach 1:
Instead of scanning the entire marking carrier to determine the angle of rotation, the system uses the temporal information of the sensor signal to identify specific marking sections (e.g., tooth gaps) that correspond to known angular positions. By partially scanning only the necessary portions of the marking carrier and using time-based identification, the system achieves accurate angle detection with significantly reduced scanning time, thus resolving the contradiction between precision and speed.
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 method allows for faster and more efficient detection of the motor shaft's angle of rotation, reducing the need for multiple sensors and simplifying the design process, while enabling adaptable tolerance ranges based on rotational speed and position, thus improving cost-effectiveness and universality.
Implementation Method 1
a first marking carrier with sensor-readable markings is provided, the markings forming a first marking pattern... the first marking carrier is scanned by means of a first sensor and a first sensor signal is generated by the first sensor during scanning, the first sensor signal being modulated by means of the markings on the first marking carrier
Data Source
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AI summary
The method involves obtaining mark portions from a sensor signal (151), and determining an exclusion criterion for excluding the mark portions. A determination is made to find whether a difference of total number of stored mark portions and number of excluded mark portions is equal to one. A rotating angle of an engine is determined from non-excluded marking portions. The marking sections are scanned in a rotation direction of a marking carrier (110) i.e. toothed wheel, by sensors (141) and are counted by a computing unit (30), where the sensors are provided with marks (133-137) or teeth.