Rotation Sensor Circumferential Magnetic Array Signal Processing
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Solution Overview
Problem
Existing rotation sensors face challenges in accurately detecting the electrical angle of a shaft with high precision and space constraints, particularly when installed on motors where securing axial space is difficult.
Innovation Solution
A rotation sensor system comprising multiple magnetic sensors arranged at equal intervals around the outer periphery of the shaft, outputting sine and cosine wave signals, and an arithmetic unit that processes these signals to cancel high-order components, allowing for precise electrical angle detection without requiring axial space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If magnetic sensors are arranged around the outer periphery of the shaft, then axial space requirements are reduced, but measurement precision deteriorates due to increased distance from the magnetic field source
Solution Approach 1:
The patent divides the detection task into multiple magnetic sensors arranged circumferentially around the shaft outer periphery. By segmenting the detection function across multiple sensors positioned at equal intervals, the system achieves accurate electrical angle detection without requiring axial space, as each sensor contributes to the overall measurement through signal combination
Solution Approach 2:
The patent transitions from axial arrangement (one-dimensional) to circumferential arrangement (two-dimensional) of magnetic sensors. By positioning sensors around the outer periphery of the shaft in the circumferential direction rather than along the axial direction, the system eliminates axial space requirements while maintaining detection capability through the spatial distribution of sensors in the radial-circumferential plane
2Measurement precision
If multiple magnetic sensors are used to improve measurement precision, then electrical angle detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent employs asymmetric signal processing where sine wave and cosine wave signals are generated with specific phase relationships. The arithmetic unit applies predetermined rules to add and subtract these signals, creating an asymmetric computational approach that cancels high-order components and improves measurement precision while managing the complexity of multiple sensors
Solution Approach 2:
The magnetic sensors serve multiple functions: they detect magnetic field changes, generate sine and cosine wave signals, and contribute to canceling high-order components through arithmetic processing. This multi-functionality allows the same sensor array to achieve both high measurement precision and simplified overall system design
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
The system achieves high-accuracy electrical angle detection with minimal waveform distortion, enabling efficient vector control of motors even under space-constrained conditions.
Implementation Method 1
magnetic sensors for outputting a sine wave signal and a cosine wave signal corresponding to an electrical angle of rotation of the rotating body... detect a change in magnetic field caused by the change in the rotational position of the rotating body
Data Source
AI summary
The rotation sensor includes a plurality of magnetic sensors for outputting a sine wave signal and a cosine wave signal corresponding to an electrical angle of rotation of the rotating body, and the magnetic sensors are arranged at equal intervals and in a circumferential direction of the rotating body apart from the outer periphery of the rotating body, and are fixed in position so as to detect a change in magnetic field caused by the change in the rotational position of the rotating body due to the rotation of the rotating body. The rotation sensor includes an arithmetic unit, which receives sine wave signals and cosine wave signals from a plurality of magnetic sensors, and adds and subtracts sine wave signals and cosine wave signals according to a predetermined rule, thereby cancels out the high-order components contained in sine wave signals and cosine wave signals.