Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras
A Combined Reluctance-hall Effect Based Angle Sensor
Categories for this Invention
Category – Sensor Technology
Applications – Automotive Steering Systems, Industrial Robotics, Renewable Energy
Industry – Automotive, Industrial Automation
Market – Global automotive steering system market was valued at USD 36.33 billion in 2023 and is expected to grow at a CAGR of 2.4%.
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Problem Statement
- Existing angle sensors face limitations such as short lifespan, sensitivity to harsh environments, and complexity in installation, especially for through-shaft applications like brake wear sensors or steering wheel angle sensors.
- Current solutions combining Hall-Effect and variable reluctance techniques are either complex, inaccurate, or require special signal conditioning, indicating a need for a simpler and more efficient angle sensing solution.
- The objective is to develop an angle sensor that combines the benefits of Hall-Effect and variable reluctance technologies, particularly for through-shaft angle sensing applications.
Technology
- The invention introduces an angle sensor combining Hall-Effect sensing and variable reluctance techniques, consisting of ring-shaped magnetic sensor parts fixed to a non-magnetic ring attached to the rotating target. Hall-Effect sensors and a permanent magnet may be incorporated between these parts for enhanced sensitivity.
- A linearizing digital converter (LDC) circuit is proposed to achieve a linear direct-digital output from the angle sensor, employing a dual-slope ADC technique with single pole double throw (SPDT) switches, an op-amp configured as an integrator, and a comparator connected to a control and logic unit (CLU).
- The method for measuring angle involves positioning magnetic sensor parts relative to the rotating target, using fixed magnetic field sensing devices between them and a magnetic flux source to impose flux. The control unit measures the output signal from the sensing devices to derive a linear direct-digital output, providing accurate angle measurements.
Key Features / Value Proposition
Enhanced Sensing Accuracy:
- Combining identical ring-shaped magnetic sensor parts and linear Hall-Effect sensors ensures precise angle detection with finite reluctance and minimal error.
Robust Mechanical Integration:
- Non-magnetic ring mechanically locked to the rotating target ensures stable and reliable sensor placement, ideal for harsh industrial environments.
Expanded Angular Range Options:
- Detection capabilities ranging from 150 to 360 degrees cater to diverse application needs, providing flexibility and versatility.
Linear Direct-Digital Output:
- The Linearizing Digital Converter (LDC) circuit with third-order-polynomial transfer characteristics delivers a linear direct-digital output for straightforward data interpretation and integration.
Efficient Signal Processing:
- Utilizing Single Pole, Double Throw (SPDT) switches, an integrator op-amp, and a comparator in the LDC circuit ensures efficient signal processing, enhancing system performance.
Streamlined Measurement Process:
- The method’s systematic approach involving fixed magnetic field sensing devices, magnetic flux sources, and a control unit facilitates straightforward and accurate angle measurement, optimizing operational efficiency.
Questions about this Technology?
Contact For Licensing
sm-marketing@imail.iitm.ac.in
ipoffice2@iitm.ac.in
Research Lab
Prof. Boby George
Department of Electrical Engineering
Intellectual Property
- IITM IDF Ref. 1021
- IN 393904 – Patent Granted
Technology Readiness Level
TRL – 3
Proof of concept stage.