Capacitive Grating Displacement Measurement via Frequency Parameter Changes
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Solution Overview
Problem
Traditional capacitive grating transducers with phase detection have limited resolution due to fixed relationships with operating frequency and manufacturing constraints, making high-resolution displacement measurement challenging.
Innovation Solution
A displacement measurement device comprising a drive signal generating circuit, signal processing circuit, and a computing device with timers and processors that convert timing data into absolute displacement values, allowing for high-resolution measurements without reducing grating spacing, by using a clock frequency divider circuit and integrating the drive signal generating circuit and signal processing circuit on a chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the grating spacing of the capacitive grating transducer is reduced to increase resolution, then measurement precision is improved, but manufacturing precision and assembly difficulty worsen due to manufacturing and assembly technology limitations
Solution Approach 1:
The patent changes the operating frequency parameter of the capacitive grating transducer to increase resolution without modifying the grating spacing. By operating at higher frequencies, the system achieves finer measurement resolution while maintaining the original grating structure, thus avoiding manufacturing difficulties associated with reducing grating spacing.
Solution Approach 2:
The patent replaces mechanical adjustment methods (reducing grating spacing) with an electronic/software-based solution. By using a computing device to process signals at higher frequencies and perform sophisticated signal analysis, the system achieves high resolution without mechanical modification of the grating structure.
2Measurement precision
If the operating frequency of the capacitive grating transducer is increased to improve resolution, then measurement precision is improved, but device complexity increases due to additional timing and counting circuits
Solution Approach 1:
The patent makes the computing device perform multiple functions: it processes the capacitive signal, performs timing measurements, executes counting operations, and calculates displacement values. By consolidating these functions into a single computing device, the system achieves high resolution without proportionally increasing device complexity.
Solution Approach 2:
The patent introduces a computing device as an intermediary between the capacitive grating transducer and the final measurement output. This intermediary handles the complex timing and counting operations, allowing the sensor itself to remain simple while achieving high resolution through computational processing.
3Device complexity
If traditional phase detection methods are used with fixed grating spacing, then device complexity is kept low, but measurement precision is limited due to fixed resolution constraints
Solution Approach 1:
The patent transforms the fixed resolution system into a dynamic one. Instead of having fixed resolution determined by grating spacing, the system dynamically adjusts its measurement capability by operating at variable frequencies and using real-time computational processing to achieve high resolution regardless of the physical grating dimensions.
Data Source
AI summary
A displacement measurement device for a sensing device. The sensing device includes a first displacement sensor. The displacement measurement device includes: a drive signal generating circuit configured to output a drive signal to the first displacement sensor; a first signal processing circuit configured to receive a signal from the first displacement sensor and output a first ADSO signal; and a computing device including a first timer. The first timer is configured to receive a CLK512 signal and the first ADSO signal, and time or count according to the CLK512 signal and the first ADSO signal; and the CLK512 signal is a square wave signal related to a period and phase of the drive signal.