A method of improving the resolution and accuracy of rotary encoders using code compensation technique

Hagiwara, Nobumi; Suzuki, Yoshihisa; Murase, Hideaki

doi:10.1109/imtc.1991.161572

Cited by 17 publications

(19 citation statements)

References 2 publications

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“…Signal Processing of Sinusoidal Encoder [1]- [3] Sinusoidal encoders encode position information by providing a pair of quadrature sine and cosine signals as the shaft is rotated. Fig.…”

Section: Analysis Of Gain and Offset Errors Of Sinusoidal Encodermentioning

confidence: 99%

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Compensation of analog rotor position errors due to nonideal sinusoidal encoder output signals

Lee

Kim

Choi³

2010

2010 IEEE Energy Conversion Congress and Exposition

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This paper proposes a compensation algorithm of analog rotor position errors due to nonideal sinusoidal encoder signals. The position sensors such as resolvers or incremental encoders are being replaced by sinusoidal encoders that offer much higher resolution. However, the periodic position errors are generated by the gain and offset errors between sine and cosine signals. In this paper, the effects of the gain and offset errors are analyzed by using dq-axis component. The analog position errors can be easily corrected by integral operation of the d-axis component. Therefore, the proposed algorithm does not need additional hardware and much computation time. The validity of the proposed algorithm is verified through experimental results. Index Terms-Sinusoidal encoder, analog rotor position errors, gain error, offset error, dq-axis component, integral operation

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“…Signal Processing of Sinusoidal Encoder [1]- [3] Sinusoidal encoders encode position information by providing a pair of quadrature sine and cosine signals as the shaft is rotated. Fig.…”

Section: Analysis Of Gain and Offset Errors Of Sinusoidal Encodermentioning

confidence: 99%

“…However, the price of a digital incremental encoder overwhelmingly increases according to its resolution, and it is the problem of bandwidth limitation. On the other hand, the sinusoidal encoder provides high resolution and accuracy for high performance applications [1]- [3].…”

Section: Introductionmentioning

confidence: 99%

Compensation of analog rotor position errors due to nonideal sinusoidal encoder output signals

Lee

Kim

Choi³

2010

2010 IEEE Energy Conversion Congress and Exposition

View full text Add to dashboard Cite

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“…Much time is taken for computation (about 2 ms), so the bandwidth of input signals will be limited. LUT based methods are discussed in [2][3] [4], but these methods occupy much memory space to store the LUTs. They cannot compensate the signal in real-time.…”

Section: Introductionmentioning

confidence: 99%

A new approach based-on advanced adaptive digital PLL for improving the resolution and accuracy of magnetic encoders

Hoang

Jeon

2008

2008 IEEE/RSJ International Conference on Intelligent Robots and Systems

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Position sensors using magnetic effects, such as magnetic encoders (MEs), are increasingly used in many industrial applications. These include motor control, electro-mechanical braking systems, and precision measurement systems. The magnetic encoders generally provide a pair of sinusoidal signals dephasing 90 0 to each other. Unfortunately, the signals obtained are not ideal, in that they always exist with the DC offsets, different amplitudes, phase-shifts and waveform distortions. These are further compromised by noise and changes in operating conditions. This paper proposes an approach for real-time correcting and tracking ME signals based on the Advanced Adaptive Digital Phase-Locked Loop (AADPLL) technique. AADPLL provides a robust filtering characteristic as well as a wideband of input frequency. It can effectively filter noise and improve the accuracy of ME signals. AADPLL also takes advantage of tracking high-speed input signals without time-lag, unlike traditional filters. A quadrature pulse interpolator is introduced to obtain high resolution. This interpolator uses look-up tables (LUTs) to store pulse-out values in one period of MEs signals. These LUTs are reduced in size for easy implementation in Digital Signal Processor (DSP) hardware platforms. Experimental results demonstrate the effectiveness of the proposed method.

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“…[4] and [7] use the same idea which relies on high-order sinusoids to generate the pulses. The code compensation method shown in [8] is based on phase-encoding In general, some of the above approaches require much computation as well as use a large memory to save the look-up table, the other approaches lack parts such as the pulses generator, direction detector and so on. The goal of this paper is to design a system that can compensate online the error parameters, extract the high resolution in standard quadrature pulses, and reduce the computation as much as possible to easily implement in a low-cost DSP system.…”

Section: Introductionmentioning

confidence: 99%

“…The goal of this paper is to design a system that can compensate online the error parameters, extract the high resolution in standard quadrature pulses, and reduce the computation as much as possible to easily implement in a low-cost DSP system. Some improvements based on [8] are applied to correct the DC offsets, phase-shift, amplitude differences and sinusoidal deformation of the output signals of MEs. In reality, there are a lot noises affecting directly the output lines of MEs and they are different in the low and high frequency domain of these output signals, due to this, the digital third-order low-pass filters (LPFs) are effectively applied.…”

Section: Introductionmentioning

confidence: 99%

Signal compensation and extraction of high resolution position for sinusoidal magnetic encoders

Hoang

Jeon

2007

2007 International Conference on Control, Automation and Systems

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MEs (magnetic encoders) are widely used in industrial control systems because of its significant advantages, such as high resolution, high speed, operation in harsh environments, and low cost. This paper describes a method to extract the position information with high resolution for sinusoidal MEs. A code compensator based on optimization theories is applied to correct non-ideal signals of the encoder outputs. This algorithm can effectively eliminate the DC offset, phase-shift, amplitude difference and sinusoidal deformation from these outputs. Then, a size-reduced look-up table is built-up off-line to generate the high resolution quadrature pulses suitable for standard incremental encoder signals. These LUTs (Look-up tables) rely on the approximate linear property of the amplitude of sinusoids in section [-sin(~/4) ; sin(~/4)] and is decreased by converting the values of LUTs into binary values (0 and 1). The ffl'mware is implemented on a 16-bit DSP (Digital Signal Processor) TMS320F2812 hardware platform with minimum computation. The experimental results are also presented in this paper.

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A method of improving the resolution and accuracy of rotary encoders using code compensation technique

Cited by 17 publications

References 2 publications

Compensation of analog rotor position errors due to nonideal sinusoidal encoder output signals

Compensation of analog rotor position errors due to nonideal sinusoidal encoder output signals

A new approach based-on advanced adaptive digital PLL for improving the resolution and accuracy of magnetic encoders

Signal compensation and extraction of high resolution position for sinusoidal magnetic encoders

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