Alternating Electric Field Planar 2D Time Grating Displacement Sensor
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Solution Overview
Problem
Traditional two-dimensional displacement sensors face challenges in achieving high-precision, large-range, and interference-resistant measurements due to complex structures and signal interference, particularly in multi-dimensional motion applications, where existing technologies like optical, magnetic, and capacitive gratings suffer from Abbe errors and low accuracy.
Innovation Solution
An alternating electric field based plane 2D time-grating displacement sensor with a staggered arrangement of excitation electrodes and induction units, utilizing sinusoidal excitation signals and differential structures to decouple signals and enhance anti-interference capabilities, allowing for high-precision plane 2D linear displacement measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If two-dimensional optical gratings are used for plane 2D displacement measurement, then measurement coverage is improved, but manufacturing complexity and optical path structure become complex, and cost increases
Solution Approach 1:
The patent replaces the optical grating system with an electric field-based time grating system. Instead of using optical paths and mechanical grating structures, the invention uses alternating electric fields generated by excitation electrodes to create time-grating signals for displacement measurement in both X and Y directions, thereby eliminating complex optical components and simplifying the manufacturing process
Solution Approach 2:
The patent applies periodic alternating electric fields through excitation electrodes arranged in a grid pattern. By applying sinusoidal excitation signals with different phases to different electrode groups, time-grating signals are generated that enable displacement measurement without requiring physical grating structures, thus reducing manufacturing complexity while maintaining large measurement range
2Measurement precision
If two-dimensional magnetic gratings or capacitive gratings are used for plane 2D displacement measurement, then measurement capability is improved, but signal interference between two directions occurs, resulting in low measurement accuracy
Solution Approach 1:
The patent segments the measurement function into four independent excitation phases (A, B, C, D) with 90-degree phase differences. Each phase corresponds to a specific electrode group, allowing independent signal generation for X and Y direction measurements. This segmentation prevents signal interference by ensuring that excitation signals in different directions are temporally separated through phase differentiation
Solution Approach 2:
The patent changes the temporal parameter of the excitation signals by applying sinusoidal signals with different phases (0°, 90°, 180°, 270°) to different electrode groups. This phase parameter differentiation allows the system to distinguish between X and Y direction signals, eliminating cross-direction interference while maintaining measurement precision
3Measurement precision
If traditional one-dimensional time-grating sensors are used, then high-precision linear displacement measurement is achieved, but plane 2D linear displacement measurement cannot be realized
Solution Approach 1:
The patent extends the one-dimensional time-grating concept to two dimensions by arranging excitation electrodes in a grid pattern with both X and Y direction electrode groups. By applying phased excitation signals to these multi-directional electrode groups, the system generates time-grating signals that simultaneously encode displacement information in both X and Y directions, enabling plane 2D displacement measurement while maintaining high precision
Solution Approach 2:
The patent creates a universal measurement system where the same excitation electrode structure serves multiple functions: generating time-grating signals for X direction measurement, Y direction measurement, and providing phase references for signal processing. This multi-functionality allows the system to achieve 2D displacement measurement capability while maintaining the high precision of 1D time-grating sensors
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
The solution enables high-precision, large-range plane 2D displacement measurement with improved signal decoupling and anti-interference ability, simplifying the structure and enhancing measurement accuracy compared to traditional sensors.
Implementation Method 1
uses an alternating electric field constructed by a plate capacitor to directly couple electric traveling wave signals required for measurement
Implementation Method 2
A coupling capacitor is formed between the induction unit and the square excitation electrode facing to the induction unit
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
Disclosed is an alternating electric field based plane 2D time-grating displacement sensor which includes two parts: the base of fixed ruler (1) and the base of moving ruler, and the two parts are installed in parallel and facing to each other with a gap therebetween. The base of fixed ruler (1) is arranged with square excitation electrodes (11) that are respectively staggered coded along axis X and Y, and the base of moving ruler (2) is arranged with induction electrodes (a, b, c, d) arranged adjacently along X-axis and Y-axis, sinusoidal excitation signals with the same frequency and same amplitude with a phase difference of 90° are respectively applied to four excitation phases, and the four induction groups respectively output four traveling wave signals through electric field coupling, and summation of adjacent output signals with an adder can simultaneously decouple two traveling wave signals with opposite phases and only containing X-axis displacement and two traveling wave signals with opposite phases and only containing Y-axis displacement; two traveling wave signals in either direction are differenced by a subtractor to eliminate common mode interference. The sensor has a simple structure and decouples completely, which can realize high precision plane 2D displacement measurement over a large range.