Optimization of Magnet Dimension for MIEC Speed Sensor Using Gradient Projection Algorithm

Motion-induced eddy current (MIEC) testing method has been successfully applied in speed measurement, where the performance of the sensor is highly dependent on the dimensions of the permanent magnet. In this article, an optimization method based on the gradient projection algorithm is proposed to determine the optimal magnet dimensions and enhance measurement sensitivity. First, the principle of MIEC is analyzed based on a 2-D theoretical model. Subsequently, an optimization-based mathematical model employing the gradient projection algorithm is developed, and the corresponding optimized results are obtained. Finally, experimental validation is conducted using a rotating aluminum disk platform. The results indicate that, within the practical dimensional ranges of 40 mm in width and 30 mm in height, the optimized permanent magnet dimensions are with a width of 27.6 mm and a height of 30 mm, which yield the best measurement sensitivity.