Sinusoidal Encoder Disk Reference Curves for Position Accuracy
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Solution Overview
Problem
Existing encoder disks for determining the rotational position of rotary components suffer from accuracy limitations due to their rectangular function periods, which hinder precise positional determination.
Innovation Solution
The encoder disk is designed with periods composed of monotonically increasing and decreasing function portions, allowing for a sinusoidal progression, and the use of shifted measurement curves to determine the rotational position with greater accuracy through the application of an arctangent function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rectangular function periods are used in the encoder disk, then the device structure is simple, but the measurement precision of rotational position is limited
Solution Approach 1:
The encoder disk outer contour is changed from rectangular function periods to sinusoidal function periods. This parameter change in the mathematical function describing the outer contour enables continuous monotonic progression in each quadrant, which significantly improves rotational position measurement accuracy by allowing precise determination of angular position through the sinusoidal variation pattern.
Solution Approach 2:
The encoder disk outer contour is designed with sinusoidal curvature instead of rectangular straight lines and sharp corners. The sinusoidal shape provides smooth continuous curves that enable more precise optical measurement of rotational position, as the curved profile creates gradual intensity variations in the measured values that are easier to measure accurately than the abrupt transitions in rectangular patterns.
2Manufacturing precision
If rectangular function periods are used in the encoder disk, then the manufacturing process is simple, but the positional resolution is insufficient
Solution Approach 1:
The mathematical function defining the outer contour is changed from rectangular to sinusoidal. This parameter change transforms the geometric description from piecewise linear segments to a continuous trigonometric function, which provides smoother transitions and enables more precise determination of intermediate angular positions through the continuous nature of sinusoidal variation.
Solution Approach 2:
The encoder disk design transitions from static rectangular profiles to dynamic sinusoidal profiles that provide continuous variation. The sinusoidal outer contour creates a dynamic measurement signal with continuous intensity changes, enabling more precise detection of rotational position compared to the discrete, step-like transitions in rectangular patterns.
3Measurement precision
If monotonically increasing and decreasing function portions are used, then the rotational position can be determined with greater accuracy, but the device complexity increases
Solution Approach 1:
Each period of the sinusoidal outer contour is segmented into two function portions: a monotonically increasing portion and a monotonically decreasing portion. This segmentation allows the measurement system to determine rotational position by identifying which portion is active and calculating the position within that portion, improving accuracy while managing system complexity through structured data processing.
Solution Approach 2:
The sinusoidal outer contour creates periodic measured values as the encoder disk rotates. By utilizing the periodic nature of the sinusoidal function with its alternating increasing and decreasing portions, the system can determine rotational position through phase detection and waveform analysis, achieving high precision through the regular, predictable periodic pattern.
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 design enables precise determination of the rotational position with enhanced accuracy by utilizing a reference curve derived from shifted measurement curves, improving positional resolution.
Implementation Method 1
The beam source generates a measuring beam which strikes or passes through a slotted encoder disk, so that the measuring beam is allowed through or blocked. The sensor unit, which is designed as an optical detector or a reading head, detects the passing through of the measuring beam and generates a corresponding electrical signal.
Data Source
AI summary
A device for determining a reference curve for a rotational position of a rotary component rotatable about an axis of rotation. An encoder disk is connected to the rotary component and is rotatable about the axis of rotation where the encoder disk is circular and has a periodic outer contour with periods. A beam source emits a measuring beam directed onto the periodic outer counter of the encoder disk. A control unit is connected to a sensor unit. Each of the periods of the periodic outer contour of the encoder disk are made up of a respective first function portion and a respective second function portion where the first function portion and the second function portion follow a monotonic progression and where one of the first function portion and the second function portion increases monotonically and the other of the first function portion and the second function portions decreases monotonically.