Repetitive Control for an Electrostatic Microbridge Actuator

2005 ◽  
Author(s):  
Haiyu Zhao ◽  
Christopher D. Rahn ◽  
Huseyin Canbolat
Keyword(s):  
Control Algorithm ◽  
Repetitive Control ◽  
Squeeze Film ◽  
Transverse Displacement ◽  
Residual Vibration ◽  
Rf Switches ◽  
Squeeze Film Damping ◽  
High Bandwidth ◽  
Offline Processing ◽  
Measured Response

Electrostatic microactuators are used extensively in MEMS sensors, RF switches, and microfluidic pumps. Due to high bandwidth operation, however, reduction of residual vibration using feedback control is diffcult to implement. This paper designs, proves stability, and simulates a feedforward repetitive controller for an electrostatic microbridge. Squeeze film damping ensures boundedness of the distributed transverse displacement. Offline processing using repetitive control algorithm updates a waveform generator’s parameters based on measured response to reduce errors between the desired and actual displacement distribution. Simulations show a 36% reduction in midspan overshoot.

Coupled effects of surface interaction and damping on electromechanical stability of functionally graded nanotubes reinforced torsional micromirror actuator

2021 ◽  
pp. 030932472110368
Author(s):  
Weidong Yang ◽  
Menglong Liu ◽  
Linwei Ying ◽  
Xi Wang
Keyword(s):  
Casimir Force ◽  
Volume Fraction ◽  
Nonlocal Parameter ◽  
Saddle Points ◽  
Functionally Graded ◽  
Heteroclinic Orbits ◽  
Phase Portraits ◽  
Squeeze Film ◽  
Squeeze Film Damping ◽  
Tilting Angle

This paper demonstrated the coupled surface effects of thermal Casimir force and squeeze film damping (SFD) on size-dependent electromechanical stability and bifurcation of torsion micromirror actuator. The governing equations of micromirror system are derived, and the pull-in voltage and critical tilting angle are obtained. Also, the twisting deformation of torsion nanobeam can be tuned by functionally graded carbon nanotubes reinforced composites (FG-CNTRC). A finite element analysis (FEA) model is established on the COMSOL Multiphysics platform, and the simulation of the effect of thermal Casimir force on pull-in instability is utilized to verify the present analytical model. The results indicate that the numerical results well agree with the theoretical results in this work and experimental data in the literature. Further, the influences of volume fraction and geometrical distribution of CNTs, thermal Casimir force, nonlocal parameter, and squeeze film damping on electrically actuated instability and free-standing behavior are detailedly discussed. Besides, the evolution of equilibrium states of micromirror system is investigated, and bifurcation diagrams and phase portraits including the periodic, homoclinic, and heteroclinic orbits are described as well. The results demonstrated that the amplitude of the tilting angle for FGX-CNTRC type micromirror attenuates slower than for FGO-CNTRC type, and the increment of CNTs volume ratio slows down the attenuation due to the stiffening effect. When considering squeeze film damping, the stable center point evolves into one focus point with homoclinic orbits, and the dynamic system maintains two unstable saddle points with the heteroclinic orbits due to the effect of thermal Casimir force.

Deep Hole Honing Based on Squeeze Film Damping Technology

2009 ◽  
Vol 76-78 ◽  
pp. 252-257
Author(s):  
Tian Biao Yu ◽  
Ya Dong Gong ◽  
Wan Shan Wang
Keyword(s):  
Differential Equation ◽  
Experimental Result ◽  
Squeeze Film ◽  
Design Parameters ◽  
Improve Quality ◽  
Deep Hole ◽  
Squeeze Film Damper ◽  
Squeeze Film Damping ◽  
Hole Machining

In order to improve quality of deep hole machining, a new method of deep hole honing based on squeeze film damping technology is put forward. For analysis effect on damper parameters on honing quality, motion differential equation of honing spindle with a squeeze film damper (SFD) is established according to D' Alembert principle and according simulations are studied. Spindle of deep hole honing with a SFD is designed based on the result of simulations and experiments are carried on. Experimental result shows that SFD with reasonable design parameters has excellent damping function to honing spindle, and it can make the vibration of honing spindle reduced 20%～30% and the quality of deep hole machining improved 10%～20%.

Vibration Control of Moving Flexible Structure by Repetitive Control

1995 ◽  
Author(s):  
Shinji Mitsuta ◽  
Hideki Tsuji ◽  
Hiroyuki Itoh ◽  
Yasushi Ogasawara ◽  
Kazuto Seto
Keyword(s):  
Feedback Control ◽  
Control Method ◽  
Repetitive Control ◽  
Model Identification ◽  
Step Response ◽  
Flexible Structure ◽  
Hydraulic Actuator ◽  
Residual Vibration ◽  
Vibration Displacement ◽  
Simulation And Experiment

Abstract The purpose of this study is to move a flexible structure, such as conveyance equipment that moves periodically, quickly and accurately by controlling its vibration. In order to reduce the vibration of a flexible structure actively, a hydraulic actuator is arranged on the motion transmission path between a drive system and a flexible structure. Generally, it is possible to obtain good effects for reducing a residual vibration by using feedback control. However, the vibration displacement in motion is mainly forced vibration which is caused by motion acceleration, so it is difficult to reduce the vibration displacement by using feedback control. Thus, by considering that the flexible structure is driven periodically, we use the repetitive control method to reduce the vibration displacement in motion. In this study, the repetitive control method with the step response, which does not need model identification, is shown. Furthermore, the validity of this method is examined by simulation and experiment.

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