This paper presents an optimization method for the structural parameters of a proportional solenoid. The 3D finite element method simulation model for performance analyse of proportional solenoid was validated by force-displacement characteristic experiment. Parameter sensitivity analysis results showed that the displacement of the armature, the length of the armature, the radius of the armature, the width of the first half of the sleeve and the angle of the magnetic-isolated ring have significant effects on the electromagnetic force. Key structural parameters were optimized according to the simulation results. Experiments results showed the average electromagnetic force was increased by 20.1 % and the effective stroke was extended to 2.1 mm.

This paper presents a design method of a robust tracking controller satisfying multiple constraints using genetic algorithm. A robust H∞ constraint with loop shaping is used to address disturbance attenuation with error limits and a loop gain constraint is considered so as not to enlarge the tracking loop gain and bandwidth unnecessarily. The robust H∞ constraint is expressed by a matrix inequality and the loop gain constraint is considered as an objective function so that genetic algorithm can be applied. Finally, a robust tracking controller can be obtained by integrating genetic algorithm with LMI approach. The proposed tracking controller design method is applied to the track-following system of an optical DVD recording drive and is evaluated through the experimental results.

In this paper, we provide a robust track-following controller design method for the stable coarse seek control. Due to the inaccurate velocity control during a coarse seek, the shake of fine actuator is generated and thus a gain-up track-following control is required to complete stably the coarse seek. To this end, a loop gain adjustment algorithm is introduced to estimate accurately the shake of fine actuator. A weighting function can be properly selected from a minimum tracking gain-up open-loop gain, calculated from the estimated shake quantity of fine actuator. A robust tracking gain-up controller is designed by considering a robust H∞ control problem using the weighting function. The proposed design method is applied to the coarse seek control system of an optical rewritable drive and is evaluated through the experimental results. * 1. 서 론

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