Realization of fine motion control based on disturbance observer

Recently, disturbance observer has been used in many servo system and industry applications. This paper focus on the fine motion control technology based on disturbance observer. The first motion control application of disturbance observer is the anti-slip/skid re-adhesion control of electric commuter train based on disturbance observer and sensorless vector control. The improvement of adhesion characteristics is important in electric multiple units. We have already proposed the anti-slip/skid re-adhesion control system based on disturbance observer and sensorless vector control. The effectiveness of the proposed method has been confirmed by using the tested bogie system of electric commuter train and the actual electric multiple units. The second motion control application of disturbance observer is the high speed and robust tracking servo system of optical disk recording system. The tracking servo system of optical disk recording system should keep the robust performance against both periodic disturbance and sudden disturbance. For this purpose, this servo system has the robust feedback control system using the free parameter which is designed by disturbance observer. Moreover, in order to suppress the sudden disturbance, this servo system has the sudden disturbance observer.