Design and control of pickup actuator for Near Field Recording

To understand the coupled motion between linear and
rotational motion of 3-axis actuator, generalized
actuator modeling was constructed, and from the
planar vector model of actuator, expanded equation
of motion, which could describe 3-axis motion was
built. From the equation of motion, 3x3 transfer
function matrix was obtained, and coupling behavior
was observed. To analyze the coupling behavior,
singular value decomposition of transfer function
matrix was applied and led to the conclusion that
rotational motion strongly influenced linear motion.
Therefore, to obtain decoupling system, transfer
function matrix should be a diagonal form,
and in order to do so, decoupler was inserted in
front of actuator plant model. Decoupler made the
pseudo plant, which was composed of decoupler and
original actuator plant as a diagonal form.
To change actuator plant model, design
variable was selected and optimal value range was
confirmed. Sensitivity analysis was performed to get
the critical variables, which affected coupling
motion between linear and rotational direction.

Autorentext

He received B.S and M.S and Ph.D degree from Dept. of Mechanical Engineering of the KAIST, Korea, in 1998, 2000 and 2008, respectively. He joined the VSI Group, D&S Lab., LG electronics, Korea, where he has been involved in research and development of optical pickup actuator and servo design for Near field recording system from 2002.

Klappentext

To understand the coupled motion between linear and rotational motion of 3-axis actuator, generalized actuator modeling was constructed, and from the planar vector model of actuator, expanded equation of motion, which could describe 3-axis motion was built. From the equation of motion, 3x3 transfer function matrix was obtained, and coupling behavior was observed. To analyze the coupling behavior, singular value decomposition of transfer function matrix was applied and led to the conclusion that rotational motion strongly influenced linear motion. Therefore, to obtain decoupling system, transfer function matrix should be a diagonal form, and in order to do so, decoupler was inserted in front of actuator plant model. Decoupler made the pseudo plant, which was composed of decoupler and original actuator plant as a diagonal form. To change actuator plant model, design variable was selected and optimal value range was confirmed. Sensitivity analysis was performed to get the critical variables, which affected coupling motion between linear and rotational direction.