Improving Sinusoidal Phase Errors in an Encoder Application Sensor


Toh, K. H. and Lee, Lini (2022) Improving Sinusoidal Phase Errors in an Encoder Application Sensor. Journal of Southwest Jiaotong University, 57 (5). pp. 275-286. ISSN 0258-2724

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A motor encoder is a rotary encoder mounted to an electric motor that provides closed loop feedback signals by tracking the speed and/or position of a motor shaft. The most common encoder sensor is the optical encoder whose output consists of two sinusoidal signals that are 90o phase shift apart. Using these two signals, the system can determine the speed and direction of the motor, thus providing basic closed loop feedback. In reality, these two signals are unideal thus, it can degrade the performance of an encoder and subsequently reduce the accuracy of the feedback control system. The main parameters that affect an encoder sensor are mismatch in offset, amplitude and phase between the two signals. This can be caused by either the mechanical construction or the electrical imperfection. This paper proposed a method to improve the phase error of the two sinusoidal signals by summing and subtracting the signals while using an analog circuit blocks that are already commonly used in an optical encoder. The proposed method does not require significant overhead in design and real estate of the sensor. This method is first explained and simulated using a model in MATLAB and then implemented and verified using the TSMC 0.18um CMOS process. The measured results are obtained from the fabricated integrated circuit (IC) and shown to match the design results. With the proposed method, it is demonstrated that the phase errors are significantly reduced significantly, thus are able to improve the performance of the encoder.

Item Type: Article
Uncontrolled Keywords: Optical Encoders, Phase Correction, Summing and Subtracting Amplifier, Sinusoidal Signal Improvement, Correction Method in Encoders
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK7800-8360 Electronics
Divisions: Faculty of Engineering (FOE)
Depositing User: Ms Nurul Iqtiani Ahmad
Date Deposited: 12 Jan 2023 04:05
Last Modified: 12 Jan 2023 04:05


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