Magnetic Multi-Turn Sensor Initialization State Determination
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Solution Overview
Problem
Magnetic multi-turn sensors often have an unknown initialization state when powered up, especially after being powered off, which can lead to inaccurate turn counting and fault detection, as the initialization state is typically set at the factory and not stored separately.
Innovation Solution
A method and device to determine the initialization state of a magnetic multi-turn sensor by analyzing sensor outputs, assuming one of two possible initialization states, and adjusting based on correct or incorrect readings to identify the actual state and detect any faults, using a set of states determined through resistance measurements of magnetoresistive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor is initialized at the factory with a fixed initialization state, then the sensor can accurately count turns during normal operation, but the initialization state becomes unknown when the sensor is powered off and restarted
Solution Approach 1:
The sensor system performs self-diagnosis by automatically determining its own initialization state through analyzing sensor outputs and testing assumptions about the two possible states, eliminating the need for external storage or manual tracking of initialization state information
Solution Approach 2:
The system uses feedback from sensor outputs to verify assumptions about the initialization state, comparing expected outputs against actual readings to confirm or reject hypotheses about the current state, thereby automatically recovering initialization information
2Device complexity
If the initialization state is not stored separately, then the device complexity is reduced, but there is no way to know the initialization state after power cycling
Solution Approach 1:
The sensor system autonomously determines its initialization state by analyzing its own sensor outputs and logically deducing the state based on the known two-state nature of the magnetoresistive elements, without requiring external storage devices or additional hardware
Solution Approach 2:
The patent replaces the physical storage mechanism (separate storage of initialization state) with a logical/digital determination process that uses sensor output analysis and assumption testing to recover the initialization state information
3Measurement precision
If the sensor outputs are analyzed to determine initialization state, then the initialization state can be determined after any number of turns including zero turns, but incorrect assumptions about the initialization state can lead to faulty determination
Solution Approach 1:
The system uses feedback from sensor outputs to verify each assumption about the initialization state, comparing expected sensor readings against actual readings to confirm whether an assumption is correct, thereby ensuring reliable determination even when made at any turn count
Solution Approach 2:
The system performs preliminary testing by assuming one of the two possible initialization states and checking for consistency with sensor outputs before finalizing the determination, allowing validation of the assumption before committing to a conclusion
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
Enables immediate and accurate determination of the initialization state without prior knowledge, allowing for correct turn counting and fault detection, and allows for automatic storage of the initialization state for future use.
Implementation Method 1
magnetic multi-turn sensors often include giant magnetoresistance (GMR) elements that are sensitive to an applied external magnetic field. The resistance of the GMR elements can be changed by rotating the magnetic field within the vicinity of the sensor.
Data Source
AI summary
The disclosure relates to a method of determining the initialization state of a multi-turn sensor based on the sensor outputs. The method takes a reading of the sensor outputs, and then determines whether the sensor outputs are feasible based on an assumption that the sensor is initialized in one of two states. If the sensor outputs are correct, this initial assumption is taken to also be correct. However, if an incorrect sensor output is read, then it is taken that the assumed initialization state is incorrect. The sensor is therefore taken to be initialized in the alternative state. The method will then determine whether the sensor outputs are feasible based on this second assumption, and if an incorrect sensor output is still being read, then there is a fault in the multi-turn sensor.