Analysis and Control on a Specific Electromagnetic Micromirror

Abstract

In this paper, 10 resonant modes were divided based on the structure of a specific two-dimensional electromagnetic micromirror from Professor Shen’s team and Finite Element Method (FEM), and using as many as 10 resonant modes to do such analysis was the first time according to the best of our knowledge. The results showed that the slow axis can participate in several resonant motions under the signals of resonant frequencies. In particular, participating in Mode 1 for slow-scan axis was the key reason to the instability of Vertical Refreshing Scanning (VRS) in raster scanning. In addition, a piecewise PID control based on filters design for this electromagnetic micromirror was proposed to suppress the unexpected resonant oscillation and to improve the angular positioning accuracy in slow-scan axis control. Finally, the proposed method was applied to electromagnetic micromirror stages, and the experimental results showed that the proposed approach was reliable.

Model guided extremum seeking control of electromagnetic micromirrors

“…For comparison, the secondary filtering approach developed in Ref. 8 is also used to suppress the influence of noise on the output measurement of EMM. Figure 11 shows the corresponding filtering result of the secondary filter in time-domain.…”

“…However, specifying the optimal gains for PID controller is not an easy task since the optimization procedure, in this case, is a nonconvex problem. In our previous work 8 , it is shown that the slow-scanning axis in the EMM system participated in several resonant motions under the signals of resonant frequencies, especially in the resonant movement on the slow-scanning axis shown in Fig. 2 , which was the main reason of the instability in the control of electromagnetic micromirror.…”

“…It is known that the deflection mechanism of the EMM can be described by where y is the deflection angle, M is the mass moment of inertia, B is the damping coefficient, K is the spring constant of flexure, and T e is the electromagnetic torque which is described as 8 where Ф is the external magnetic field generated by the permanent magnets, u is the control voltage and R is the resistance of the spial coil, r i is the distance between the unit length of the coil and the axis of rotation on the i th coil, and is the angle between and . From (2) and the detailed analysis of torque to drive the mirror plate 14 , it is known that the relation between the control voltage and the drive torque has a complex mapping.…”

An Advanced Extremum Seeking Scheme for the Target Trajectory in Electromagnetic Micromirror System

“…Now two aspects are focused on to show the performance of the advanced extremum seeking scheme. Compared with the secondary filtering [8] (seen in Fig. 9 and Fig.…”

“…PID control and a low pass filter (LPF) were proposed in Han's research [7], but choosing appropriate gains for PID controller is very difficult to manage and the rings from driving coils were difficult to be eliminated. In our previous work [8], it showed that the slow axis in electromagnetic micromirror system participated in several resonant motions under the signals of resonant frequencies, especially in the resonant movement on slow-scan axis shown in fig. 1, which is the main reason of the instability in the control of electromagnetic micromirror.…”