Hybrid AMR and Hall Sensor System for 360-Degree Angle Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetic rotary position sensors, particularly those using anisotropic magneto-resistive (AMR) and Hall sensors, face limitations in detecting a full 360-degree angle range with high precision, often requiring precise sensor placement and experiencing ambiguity at 180 and 360-degree angles due to temperature and process variations, and lack a cost-effective and simplified manufacturing process.
Innovation Solution
A 360-degree magnetic rotary position sensor system combining an AMR sensor with two lateral Hall sensors, where the Hall sensors are positioned with a phase shift between 0° and 90° relative to the AMR sensor's zero angle measurement position, allowing for a wide mechanical tolerance range and integrated signal processing in both analog and digital domains, enabling high precision and cost reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Hall sensors are used to detect 360-degree angle range, then the angle detection range is extended to 360°, but the measurement precision decreases compared to AMR sensors
Solution Approach 1:
The patent combines AMR sensors (providing high precision over 180°) with Hall sensors (providing 360° detection capability) into a hybrid system. The AMR sensors measure magnetic field components with high precision, while Hall sensors detect the polarity to distinguish between 0-180° and 180-360° ranges, achieving both extended range and high precision through sensor fusion
2Measurement precision
If Hall sensors are positioned with precise phase shift to achieve accurate angle detection, then the measurement precision is improved, but the device complexity increases due to stringent placement requirements
Solution Approach 1:
The patent uses two AMR sensor bridges oriented at 45° to each other, creating redundant measurement channels. This redundancy allows the system to compensate for placement variations and achieve accurate angle detection without requiring extremely precise Hall sensor positioning, as the AMR sensors provide robust reference measurements
3Measurement precision
If AMR sensors are used for high precision angle sensing, then the measurement precision is improved, but the angle detection range is limited to 180°
Solution Approach 1:
The patent introduces Hall sensors as intermediary elements that detect the polarity of the magnetic field to determine which 180° half-cycle the magnet is in. This intermediary measurement allows the system to extend the AMR sensor's 180° range to a full 360° range while maintaining the high precision of the AMR measurements
4Measurement precision
If a combination of AMR and Hall sensors is used to achieve 360-degree detection with high precision, then the measurement precision and angle range are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the angle detection function into two distinct parts: AMR sensors handle high-precision measurement within each 180° half-cycle, while Hall sensors handle the coarser task of identifying which half-cycle is active. This functional segmentation allows each sensor type to operate in its optimal performance range, simplifying the overall system design compared to using a single sensor type for both tasks
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 precision and safety in detecting a full 360-degree angle range with reduced manufacturing complexity and cost, providing redundant angle information for enhanced accuracy and error detection.
Implementation Method 1
An AMR sensor may include resistive elements that are configured into one or more Wheatstone bridge configurations. Each of the resistive elements may have a resistance that varies according to the magnitude and/or direction of a magnetic field that is incident upon the respective resistive element.
Implementation Method 2
Some types of AMR devices are configured to generate a unique output voltage value for rotational angles of an incident magnetic field within a range of 180 degrees. For example, an AMR device may include two Wheatstone bridge configurations oriented 45 degrees in rotation from each other.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention discloses a 360-degree magnetic rotary position sensor system whereas the object of the invention to offer an apparatus and method that allow a much wider mechanical tolerance range in the placement of the Hall sensors relative to the AMR sensor and an improved or simplified signal processing will be solved by a combination of an AMR sensor and a first and a second lateral Hall sensor and a signal processing circuit; the AMR sensor and the Hall sensors lay in one plane, whereas the AMR sensor has a zero angle measurement position and the first Hall sensor is placed relative to the zero angle measurement position in a range from 0° < phase shift < 90° counterclockwise and the second Hall sensor is placed relative to the zero angle measurement position in a range from 0° < phase shift < 90° clockwise, whereas the signal processing is designed performable in analog and/or digital. The digital signal processing unit calculates a first absolute angle with a period of 180 mechanical degrees provided by the AMR sensor signal and a second absolute angle with a period of 360 mechanical degrees by the Hall sensor signals, whereas intermediate digital signals are generated by the digital processing unit according to the calculated first and second absolute angle signals. (Fig.9)