Development of Algorithm to Estimate Sensor Offset in Maglev Tray System

Maglev (Magnetic levitation) technology is an effective way for transport to move without contacting with the ground so that it reduces friction and allows high speeds compared to any other vehicles. One of applications using maglev technology is the maglev tray system which has been introduced for carrying OLED displays. In the maglev tray system, 20 gap sensors are installed at the right and left side to measure the vertical displacement between the tray and sensor. Due to inevitable sensor installation error, fluctuated pitching motion of the tray occurs at high speed and it is hard to obtain the accurate gap measurement. Moreover, fluctuated pitching motion of the tray affects a negative effect on transport of OLED displays. In this paper, we develop an algorithm to estimate the sensor installation error and calibrate sensor offset. The measurements from gap sensor are used to estimate the mathematical correlation between its amplitude in the frequency domain and sensor offset. Using the iteration method, the accurate parameters in a linear equation are computed. The results show that our algorithmic process has been verified and we successfully obtain the results of calibrating the sensor offset.