광픽업 미세구동부의 최적설계

Abstract

In this paper, a new modeling of a fine actuator for an optical pick-up has been proposed and multiobjective optimization of the actuator has been performed. The fine actuator is constituted of the bobbin which is supported bt wire suspension, the coils which wind around the bobbin, and the magnets which cause the magnetic flux. If current flows in the coils, magnetic force is so produced as to be balanced with spring force of wire, so the bobbin is positioned. in this model the transfer function from input voltage to output displacement of bobbin has been obtained do that we can describe this intergrated system with electromagnetic and mechanical parts. Wire suspension is regarded as a continous Euler beam, damper as distributed viscous damping, and bobbin as a rigid body which can move up-and down-ward motion only. According to the model, the high frequency dynamic characteristics of the fine actuator can be known and the effect of damping can be investigated while the conventional second order model cannot. In multiobjective optimization, two objective functions have been chosen to maximize the fundamental frequency and the sensitivity with respect to the input voltage of the actuator so that Pareto's optimal solutions have been obtained using constraint method. these objective functions will satisfy the trends which will enhence the access speed and reduce the tracking error in the optical pick-ip technology of next generation. In the result of optimization, we obtain the designs of the optical pick-up fine actuator which has high speed, high sensitivity and low resonant peak. Furthermore, we offer the relation between two object functions so that the designer can make easy choice.