Subdivision Method for Nonorthogonal Moiré Signals

Zhu, Weibin; Xu, Yingkun; Huang, Yao; Xue, Zi; Ye, Shengjin

doi:10.1109/tim.2020.3039633

Cited by 8 publications

(2 citation statements)

References 22 publications

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“…Hou et al [9] realized high-precision measurement technology of a single-excitation petal-shaped capacitive encoder based on periodic nonlinear error compensation. In 2020, Zhu et al [10] proposed a method to directly subdivide non-orthogonal moiré signals, which avoids the problem of high resource occupation caused by theoretical error introduced by the CORDIC algorithm in inverse cosine calculation and orthogonal error compensation. In 2022, Hou et al [11] analyzed the generation principle of the grating moiré fringe subdivision error by the mathematical model to the characteristics of the grating signal waveform equation and proved through experiments that the method can make the overall system obtain better convergence efficiency and a more accurate fitness value.…”

Section: Introductionmentioning

confidence: 99%

An Optoelectronic Detector with High Precision for Compact Grating Encoder Application

Hou

Wang

et al. 2022

Electronics

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This paper presents a novel optoelectronic detection array that adopts the research idea of optical, mechanical and electrical integration. Through the design of new detectors and ASIC, the mutual restriction between high accuracy and miniaturization of the grating encoder is solved. A simulation model of the “broken line” detector structure and process was established that only meets the needs of a compact array layout but also ensures a good photoelectric conversion rate. In addition, we used a professional design program to complete the layout of the ASIC, which maximized the recovery of the signal received by the detector. The simulation and noise analysis results show that the SNRs of the output signal are greater than 60 dB with a 400 kHz response frequency.

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Section: Introductionmentioning

confidence: 99%

An Optoelectronic Detector with High Precision for Compact Grating Encoder Application

Hou

Wang

et al. 2022

Electronics

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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].…”

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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Improving the subdivision accuracy of photoelectric encoder using particle swarm optimization algorithm

Jiang

Dai

et al. 2022

Opt Quant Electron

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To improve the subdivision accuracy of a photoelectric encoder and reduce the effects of sinusoidal errors in the signals on the measurement accuracy of the system, we designed an optoelectronic chip to receive grating moiré fringe signals. An amplifier circuit with a hierarchical pipelined architecture was designed, and the photodetector array was matched with the code disk before processing the received signals. Thereafter, a quantitative analysis was performed on the sinusoidal errors in the signals. From the analysis results, a sinusoidal error compensation method based on the particle swarm optimization (PSO) algorithm was developed, and a subdivision error compensation model was established to correct the errors in the signals. Finally, a fast solution for the PSO algorithm was implemented on a field-programmable gate array, and a grating test platform was built for experimental verifications. The results showed that the peak-topeak subdivision error of the encoder's photoelectric signal decreased by approximately 60% from 2.98ʺ to 1.13ʺ. Therefore, the scheme proposed in this paper is expected to significantly improve the measurement accuracies of photoelectric encoders.

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Subdivision Method for Nonorthogonal Moiré Signals

Cited by 8 publications

References 22 publications

An Optoelectronic Detector with High Precision for Compact Grating Encoder Application

An Optoelectronic Detector with High Precision for Compact Grating Encoder Application

Instantaneous grating signal subdivision system with non-linear Kalman filters

Improving the subdivision accuracy of photoelectric encoder using particle swarm optimization algorithm

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