Displacement Sensor Polyphase Signal Processing for Fast Response
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Solution Overview
Problem
Existing displacement sensors with low-pass filters face a trade-off between suppressing interfering pulses and maintaining fast response, as a large time constant required for effective suppression leads to delayed output, making them unsuitable for systems needing quick response.
Innovation Solution
The displacement sensor converts output signals into polyphase component signals, which are then rectified and combined, allowing for the use of a lower-order low-pass filter with a higher cutoff frequency, thereby reducing delay and enhancing response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low-pass filter with a large time constant is used to suppress interfering pulses, then pulse suppression is improved, but response speed deteriorates
Solution Approach 1:
The output signal is segmented into multiple polyphase component signals (e.g., three-phase signals with 120-degree phase differences). Each component signal is processed separately through rectification and filtering, allowing the use of smaller time constant filters while maintaining overall pulse suppression effectiveness.
Solution Approach 2:
The invention uses periodic polyphase component signals with specific phase relationships. By rectifying and combining these periodic signals, the ripple frequency components are increased, enabling effective filtering with smaller time constants and thus faster response while still suppressing interfering pulses.
2Measurement precision
If a low-pass filter with a large time constant is used to increase rectification precision, then rectification precision is improved, but response speed deteriorates
Solution Approach 1:
The signal processing is segmented into multiple parallel paths, each handling a polyphase component signal. This segmentation allows each filter to operate with a smaller time constant while the combined output maintains high rectification precision through the constructive interference of properly phased signals.
Solution Approach 2:
The invention transitions from single-dimensional signal processing to multi-dimensional polyphase signal processing. By utilizing multiple phase dimensions and combining them appropriately, the system achieves both high precision and fast response that cannot be obtained with a single large time constant filter.
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
This approach enables fast response in displacement sensing by minimizing ripple frequency components and using a lower-order low-pass filter, ensuring timely feedback without compromising rectification precision.
Implementation Method 1
a coil and a movable magnetic core moving in accordance with displacement of an object to be measured. The coil is supplied with a periodic signal from a periodic signal source. In accordance with displacement of the movable magnetic core, an output signal of the displacement sensor varies.
Data Source
AI summary
A displacement sensor includes a primary coil (2), secondary coils (4a, 4b), and a movable magnetic core (6) movable with displacement of an object to be measured to cause voltages generated in the secondary coils (4a, 4b) to vary. The secondary coils (4a, 4b) are differentially interconnected. A polyphase signal generating unit (10) generates two-phase component signals having different phases, from a differentially combined output voltage of the secondary coils (4a, 4b). Full-wave rectifying units (16, 18) rectify the polyphase component signals, the rectified polyphase component signals are combined in a combiner (22), and the combiner output is applied to a low-pass filter (24).