An Adaptive Filter for Subdivision of Circular Grating Signal of Angle Measurement

Huang, Yao; Che, Shuangliang; Zheng, Gang; Zhu, Weibin; Zhou, Yi; Xue, Zi

doi:10.1109/tim.2022.3192068

Cited by 3 publications

(2 citation statements)

References 22 publications

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“…Optical methods predominantly depend on the disk encoder scheme, commonly denoting the grating encoder arrangement, which employs a grating disk configuration for measurement purposes [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. Previous researchers have conducted a lot of research on it, including structural optimization [ 36 ] and algorithm supplementary modifications [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. The above method mainly relies on the scale of the code disk to measure large angles.…”

Section: High-precision With Single Axismentioning

confidence: 99%

A Review: High-Precision Angle Measurement Technologies

Wang,

Ma,

Cao

et al. 2024

Sensors

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Angle measurement is an essential component of precision measurement and serves as a crucial prerequisite for high-end manufacturing. It guides the implementation of precision manufacturing and assembly. The current angle measurement methods mainly focus on multiple axes, high precision, and large measurement ranges. This article introduces the technology of angle measurement from the perspectives of single-axis and multi-axis measurement schemes. Firstly, the single-axis measurement scheme is primarily achieved through optical methods, such as encoder discs that measure energy changes and interferometric phase changes, as well as mechanical, electromagnetic, and inertial angle measurement methods, among which interferometric methods offer the highest accuracy, with high cost, and encoder discs provide the largest measurement range with an ordinary price. Secondly, in the multi-axis measurement scheme, autocollimation instruments, including plane mirrors, gratings, and self-designed targets, are the main options. Although grating encoders can achieve three degrees of freedom in angle measurement with an ordinary price, they are limited in terms of measurement range and sensitivity compared to self-designed targets. Lastly, artificial intelligence assistance precision measurement is increasingly being embraced due to significant advancements in computer performance, making it more convenient to identify the relationship between measured values and detection values. In conclusion, angle measurement plays a crucial role in precision manufacturing, and the evolving and improving technologies provide the manufacturing industry with greater choices. The purpose of this review is to help readers quickly find more suitable technical solutions according to current application requirements, such as single/multiple axes, accuracy level, measuring range, budget, etc.

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Section: High-precision With Single Axismentioning

confidence: 99%

A Review: High-Precision Angle Measurement Technologies

Wang,

Ma,

Cao

et al. 2024

Sensors

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“…The quality of signal processing in grating encoder plays a vital role in the measurement precision of the system [10][11][12][13]. In order to improve the precision and ensure the real-time measurement, it is important to find the best the signal processing algorithm and use special hardware to accelerate the algorithm [14][15][16]. The original signal has many nonideal factors, including DC bias, high-frequency noise, low-frequency noise, harmonics and so on [17,18].…”

Section: Introductionmentioning

confidence: 99%

Instantaneous grating signal subdivision system with non-linear Kalman filters

Wang

Shi

Li³

et al. 2022

Optical Design and Testing XII

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Grating encoder is a sinusoidal encoder based on grating diffraction principle, which is currently utilized in many high-precision displacement systems because of its advantageous characteristics: low cost, simple structure, works in harsh environments, high reliability, and so on. The output signal of grating encoder usually contains noise interference error, amplitude inconsistency error, DC bias error, harmonic error and quadrature phase error. These non-ideal factors are the main reasons for affecting the precision of subdivision. In the traditional signal subdivision system, it is usually necessary to compensate each kind of error separately, which will consume many hardware and computing resources and cause a significant output latency, especially in the filtering section and normalization section. In this paper, a non-linear Kalman filter-based sin-cos wave subdivision method is proposed. Compared with the traditional filtering methods, non-linear Kalman filter has higher dynamic response and can provide instantaneous phasor estimation. In addition, it can simultaneously achieve filtering, amplitude normalization, decoupling DC bias, harmonic suppression, and phase compensation functions, which significantly reduces the computational burden and facilitates the implementation on low-cost processors. In this study, a non-linear Kalman filter-based signal segmentation system is implemented on an FPGA platform and verified on a six-degree-of-freedom grating ruler platform. The results show that the single-channel output delay is only 1.8us at a 50MHz clock, which has a very high real-time ability. When the frequency and amplitude of the input signal varies, the non-linear Kalman filter can track instantaneously and has high dynamic characteristics. Experimental results show the effectiveness of this method.

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