Total error compensation of non-ideal signal parameters for Moiré encoders

Publication date: Available online 19 August 2019Source: Sensors and Actuators A: PhysicalAuthor(s): Guoyong Ye, Hongwen Xing, Hui Liu, Yingjiang Li, Biao Lei, Dong Niu, Xuan Li, Bingheng Lu, Hongzhong LiuAbstractNon-ideal encoder signal parameters generally include amplitude imbalance error, quadrature phase error, dc-offset error and harmonic distortion. These non-ideal signal parameters are the main cause of nonlinear interpolation errors for Moiré encoders. In this paper, a total error compensation strategy for correcting these non-ideal signal parameters is presented. The compensation strategy consists of a passive compensation stage and an active compensation stage, which are realized through hardware and software means, respectively. In the passive compensation stage, an optimized scanning grating with specified micro-pattern is employed to suppress the harmonic distortion. In the active compensation stage, an adaptive compensation algorithm is proposed to compensate the remained amplitude imbalance error, quadrature phase error and dc-offset error. In the experiment, a Moiré encoder using the optimized scanning grating is developed, and a digital circuit is designed by implementing the adaptive compensation algorithm into a field-programmable gate array (FPGA). The effectiveness of the total error compensation strategy has been validated by experimental results.Graphical abstract

Source: Sensors and Actuators A: Physical - August 20, 2019 Category: Physics Source Type: research