Rotational Speed Detection Using Vernier Phase Analysis
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Solution Overview
Problem
Existing methods for determining the rotational direction and speed of wheels or shafts are inefficient due to signal offsets and interference, leading to increased power consumption and limited information provision, as they require continuous monitoring and do not account for rotational frequency.
Innovation Solution
A method using sine and cosine signals from sensors like AMR, Hall, or optical transducers, employing offset compensation and phase difference calculations via the Vernier method to determine rotational direction and speed without knowing signal offsets, allowing for efficient and precise rotational speed determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous monitoring of signals is performed to determine rotational direction, then detection reliability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic sampling of sine and cosine signals at specific time intervals rather than continuous monitoring. The analysis circuit samples signals at discrete points (e.g., every 90 degrees of rotation) and processes them periodically, which dramatically reduces power consumption while maintaining reliable rotational direction detection through phase relationship analysis.
2Measurement precision
If offset compensation is continuously calculated to improve measurement precision, then detection accuracy is improved, but computational complexity and power consumption increase
Solution Approach 1:
The patent performs offset compensation in advance by sampling signals at specific predetermined points in the rotation cycle where offset effects are minimized or known. By pre-determining offset values at these specific sampling points and using them for subsequent measurements, the system achieves accurate offset compensation without continuous calculation, reducing computational complexity.
3Device complexity
If traditional methods are used to determine rotational direction, then implementation simplicity is maintained, but additional information such as rotational frequency cannot be obtained
Solution Approach 1:
The patent creates a multi-functional analysis circuit that simultaneously determines rotational direction and calculates rotational frequency using the same sine and cosine signal samples. By analyzing the phase relationships and time intervals between sampled signals, the circuit extracts multiple parameters (direction and frequency) from the same data set, eliminating the need for separate detection systems and maintaining implementation simplicity.
Data Source
AI summary
A method and a device are described for determining the rotational direction and/or rotational speed of a rotatable body on the basis of a sine signal and cosine signal, which is assignable to the rotational direction and/or rotational speed of the rotatable body and are output by a sensor, having at least one of the following steps: recording a sine signal and cosine signal, which is assignable to the rotational direction and/or rotational speed, at a point in time; determining a phase value from the sine signal and cosine signal; recording sine signals and cosine signals, which is assignable to the rotational direction and/or rotational speed, at points in time; determining phase values from the corresponding sine signals and cosine signals; calculating phase differences from the phase values and the phase value; and determining the rotational direction and/or rotational speed from the phase differences on the basis of a Vernier method.