Shinwon  Lee, Yongho  Jeon, 
    Observer Design Using Luenberger’s Observer,
    Journal of Engineering and Applied Sciences,
    Volume 13,Issue 5,
    2018,
    Pages 1052-1056,
    ISSN 1816-949x,
    jeasci.2018.1052.1056,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2018.1052.1056)
    Abstract: Commonly used solenoid valves are mainly used for industrial equipment and appliances where
simple ON/OFF operation is possible. This is because the structure of the solenoid valve is simple and the
production cost is low. It is possible to simply use the alternating method of applying the drive rated voltage
or turning off the power. This study designs a controller for precise position control and a Luenberger’s
observer for unobserved states in the use of solenoids commonly used in the industrial field. In designing an
observer an observer with a disturbance state including a non-linear term and a constant load is designed and
an appropriate gain is set. As a result, the position error was within 0.1% within about 0.1 sec of the steady
state, the state estimation for the disturbance could be possible and it could be used in the position controller.
    Keywords: Luenbergers observer;PI controller;non-linear;solenoid;disturbance observer;position