Research on the Fuzzy PID Controller of Force Servo Hydraulic Press System

Track servo development for holographic data storage

“…The difference is the tracking error signal TE (Tracking error) obtained by PP (Push-pull) method. The TE signal of the PP method: TE = A+C-(B+D), that is the difference between the left and right optical signals is used[1] . When the focus spot is on the left side of the information layer of the optical disc, the reflected laser beam passes through the objective lens and irradiates on the left side of the four photodetectors in the middle of the PDIC (Photo detector integrated circuit).…”