Angle Sensor Noise Rejection via Dual-Sensor Segmentation
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Solution Overview
Problem
Magnetic angle sensors face significant angular errors due to noise magnetic fields, such as the earth's magnetic field and leakage fields from motors, which are not adequately addressed by existing technologies, especially when the noise field strength is higher than assumed.
Innovation Solution
An angle sensor system utilizing two magnetic sensors positioned differently to detect composite magnetic fields, with a processor that calculates the angle detection value by processing signals from both sensors and accounting for the strengths and orientations of the magnetic fields, effectively reducing angular errors caused by noise fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single magnetic sensor is used to detect the magnetic field, then the device complexity is low, but the measurement precision deteriorates due to angular errors caused by noise magnetic fields
Solution Approach 1:
The detection function is segmented into two separate magnetic sensors positioned at different locations. The first sensor detects the magnetic field at a first position, while the second sensor detects the magnetic field at a second position. By segmenting the detection function across multiple sensors, the system can distinguish between the target magnetic field and noise magnetic fields, thereby improving angle detection accuracy without excessively increasing system complexity.
Solution Approach 2:
The processor acts as an intermediary that receives detection results from both magnetic sensors and performs computational processing. The processor calculates the angle detection value by combining information from both sensors, effectively mediating between the raw sensor data and the final accurate angle measurement. This intermediary processing step is crucial for eliminating angular errors caused by noise magnetic fields.
2Measurement precision
If multiple detection circuits are used to detect composite magnetic fields at different positions, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The detection functions of multiple magnetic sensors are merged into a unified angle detection system. The processor combines the detection results from the first and second magnetic sensors through computational processing to generate a single, accurate angle detection value. This merging approach allows the system to leverage multiple sensors for improved precision while presenting a simplified interface through a single output value.
Solution Approach 2:
The multiple magnetic sensors serve multiple functions: they simultaneously detect the target magnetic field, detect noise magnetic fields, and provide redundant information for error correction. The processor universally processes data from both sensors to achieve angle detection, making the system more versatile and robust against various types of magnetic interference.
3Reliability
If the noise magnetic field strength is higher than assumed, then the angular error increases, but the existing technology does not provide sufficient reduction methods
Solution Approach 1:
The system uses feedback from two independent sensor measurements to correct angular errors. The processor continuously compares the detection results from both magnetic sensors and adjusts the angle calculation to compensate for noise magnetic field effects. This feedback mechanism enables the system to maintain reliability even when noise field strength exceeds initial assumptions.
Solution Approach 2:
The system creates a composite detection approach by combining measurements from two different sensor positions. Rather than relying on a single sensor type or position, the system synthesizes information from both sensors to create a more robust angle detection value that is less susceptible to high-strength noise magnetic fields.
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 significantly reduces angular errors by using multiple detection positions and signal processing to account for noise fields, improving the accuracy of angle detection values.
Implementation Method 1
a first magnetic sensor that detects a first composite magnetic field at a first detection position, and outputs at least one first signal having a correspondence with an angle that a direction of the first composite magnetic field forms with respect to a reference direction
Implementation Method 2
a second magnetic sensor that detects a second composite magnetic field at a second detection position different from the first detection position, and outputs at least one second signal having a correspondence with an angle that a direction of the second composite magnetic field forms with respect to the reference direction
Data Source
AI summary
An angle sensor includes a first magnetic sensor that outputs a first signal, a second magnetic sensor that outputs a second signal, and a processor that performs processing for generating an angle detection value. The processing for generating the angle detection value includes first processing for determining a first candidate value of the angle detection value, second processing for performing processing for determining an (n+1)th candidate value either once or more than once while incrementing n in value by one each time, the (n+1)th candidate value being determined by performing second computing processing using the first and second signals, first and second strengths, and an nth candidate value of the angle detection value, where n is an integer of 1 or more, and third processing for assuming the candidate value last determined by the second processing as the angle detection value.