High-Accuracy Automatic Calibration of Resolver Signals via Two-Step Gradient Estimators

Wu, Zhong; Li, Yaoling

doi:10.1109/jsen.2018.2806894

Cited by 34 publications

(27 citation statements)

References 20 publications

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“…Group 1: The original signals; Group 2: The signals denoised by the low-pass Butterworth filter; Group 3: The signals denoised by the DWT based filter; Group 4: The signals denoised by the DWT-SVD based filter. Next, in order to verify the influence of the filter on the calibration accuracy, the imperfect parameters of the above signals are estimated by an automatic calibration algorithm based on two-step gradient estimators in Reference [10]. The simulation and experimental results are analyzed as follows.…”

Section: Simulation and Experimental Resultsmentioning

confidence: 99%

“…However, the strong coupling between parameters and the angular velocity in the mathematical model was undesired because the improvement of the calibration accuracy depended on the angular frequency. Therefore, an improved algorithm based on two-step gradient estimators was presented to decouple them [10]. Owing to the more accurate information of angular velocity, the calibration accuracy was further improved.…”

Section: Introductionmentioning

confidence: 99%

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Noise Reduction for High-Accuracy Automatic Calibration of Resolver Signals via DWT-SVD Based Filter

Guo

2019

Electronics

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High-accuracy calibration of resolver signals is the key to improve its angular measurement accuracy. However, inductive harmonics, residual excitation components, and random noise in signals dramatically restrict the further improvement of calibration accuracy. Aiming to reduce these unexpected noises, a filter based on discrete wavelet transform (DWT) and singular value decomposition (SVD) is designed in this paper. Firstly, the signal was decomposed into a time-frequency domain by DWT and several groups of coefficients were obtained. Next, the SVD operation of a Hankel matrix created from the coefficients was made. Afterwards, the noises were attenuated by reconstructing the signal with a few selected singular values. Compared with a conventional low-pass filter, this method can almost only preserve the fundamental and DC components of the signal because of the multi-resolution characteristic of DWT and the good correspondence between the singular value and frequency. Therefore, the calibration accuracy of the imperfect characteristics could be improved effectively. Simulation and experimental results demonstrated the effectiveness of the proposed method.

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Section: Simulation and Experimental Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Noise Reduction for High-Accuracy Automatic Calibration of Resolver Signals via DWT-SVD Based Filter

Guo

2019

Electronics

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“…The digital signals will be uploaded to the upper computer and applied with the same three ATO methods used in simulation results. It is noteworthy that, using the HIL method, the actual value of angular position can be known to evaluate error suppression performance of the RDC, whereas a practical resolver fails to provide this information [24].…”

Section: Resultsmentioning

confidence: 99%

Angle Tracking Observer with Improved Accuracy for Resolver-to-Digital Conversion

Qin

2019

Symmetry

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A resolver is an absolute shaft sensor which outputs pair signals with ortho-symmetric amplitudes. Ideally, they are sinusoidal and cosinusoidal functions of the shaft angle. In order to demodulate angular position and velocity from resolver signals, resolver-to-digital conversion (RDC) is necessary. In software-based RDC, most algorithms mainly employ a phase-locked loop (PLL)-based angle tracking observer (ATO) to form a type-II system. PLL can track the detected angle by regulating the phase error from the phase detector which depends on the feature of orthogonal symmetry in the resolver outputs. However, a type-II system will result in either steady-state errors or cumulative errors in the estimation of angular position with constant accelerations. Although type-III ATOs can suppress these errors, they are still vulnerable to high-order acceleration signals. In this paper, an improved PLL-based ATO with a compensation model is proposed. By using dynamic compensation, the proposed ATO becomes a type-IV system and can reduce position estimation errors for high-order acceleration signals. In addition, the parameters of ATO can be tuned according to the bandwidth, noise level and capability of error suppression. Simulation and experimental results demonstrate the effectiveness of the proposed method.

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“…According to this scheme, an ellipse fitting method [7] and a parameter identification algorithm [1,8] based on gradient descent were developed. On this basis, Gao [9,10] proposed iterative algorithms for self-calibration, while Wu et al [11] applied the technology detailed in [12] to design a two-step gradient estimator and realize online parameter self-calibration.…”

Section: Introductionmentioning

confidence: 99%

“…For the processing of error signals, Hyun et al [15] proposed an adaptive digital demodulation method for a sinusoidal encoder signal, and Xiujun et al [16] developed a piecewise calibration technique that provided a good trade-off between microcontroller memory size and algorithm complexity. The scheme in [11] was also a self-calibration method implemented in hardware. Simpler signal processing algorithms generally consume fewer hardware resources, motivating the solution proposed in this study.…”

Section: Introductionmentioning

confidence: 99%

Design and Implementation of a System-on-Chip for Self-Calibration of an Angular Position Sensor

Gao

Zhou

et al. 2019

Applied Sciences

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In this study, a novel signal processing algorithm and hardware processing circuit for the self-calibration of angular position sensors is proposed. To calibrate error components commonly found in angular position sensors, a parameter identification algorithm based on the least mean square error demodulation is developed. A processor to run programs and a coprocessor based on the above algorithm are used and designed to form a System-on-Chip, which can calibrate signals as well as implement parameter configuration and control algorithm applications. In order to verify the theoretical validity of the design, analysis and simulation verification of the scheme are carried out, and the maximum absolute error value in the algorithm simulation is reduced to 0.003 %. The circuit’s Register-Transfer Level simulation shows that the maximum absolute value of the angular error is reduced to 0.03%. Simulation results verify the calibration performance with and without quantization and rounding error, respectively. The entire system is prototyped on a Field Programmable Gate Array and tested on a Capacitive Angular Position Sensor. The proposed scheme can reduce the absolute value of angular error to 4.36%, compared to 7.68% from the experimental results of a different calibration scheme.

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High-Accuracy Automatic Calibration of Resolver Signals via Two-Step Gradient Estimators

Cited by 34 publications

References 20 publications

Noise Reduction for High-Accuracy Automatic Calibration of Resolver Signals via DWT-SVD Based Filter

Noise Reduction for High-Accuracy Automatic Calibration of Resolver Signals via DWT-SVD Based Filter

Angle Tracking Observer with Improved Accuracy for Resolver-to-Digital Conversion

Design and Implementation of a System-on-Chip for Self-Calibration of an Angular Position Sensor

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