Precise Position Detection of Linear Motor Movers Based on Extended Joint Transformation Correlation

The extended joint transformation correlation (EJTC) algorithm is proposed in this paper to meet the high-precision and anti-interference requirements of linear motor mover position measurement. An image measurement system for linear motor mover position is established. Stripe image movement sequences are captured using a high-speed camera. First, the image is preprocessed using a bilateral filtering method. Second, the joint power spectral function of adjacent stripe images is obtained on the basis of the joint transform correlation method. The zero-order diffraction peaks are eliminated, and interference from cross-correlated peak side lobes is avoided. Third, subpixel positioning is obtained using the oversampled discrete Fourier transform. Finally, the actual displacement of the stripe images can be obtained by combining the system calibration coefficients. An experimental measurement platform for a linear motor mover is established to verify the validity of the EJTC algorithm. The EJTC shows high measurement accuracy and strong anti-interference ability.