High-speed visualization, a powerful diagnostic tool for microactuators - retrospect and prospect

Abstract

A comprehensive testing of microactuators is decisive (i) to prove the workability, (ii) to characterize the output parameters, (iii) to provide kinematic and temperature data for a revaluation of numerical modeling, (iv) to ensure the expected response with the macroscopic world, and (v) to study the mechanism of a premature failure. All this information helps to develop well-aimed strategies for improvements and promote the marketing process of new types of actuators. The most important diagnostic methods encompass high-speed photomicrography, laser interferometry and scanning laser Doppler velocimetry. High-speed thermography and flash microradiography have not yet been fully established for dynamic testing in the microscopic domain because of various technical limitations. The present state of the art of these methods is discussed and illustrated at various microactuator types. By the example of a microrelay it is shown that also material data can be derived from a motion analysis and that the relay operability can be improved by using methods of systems theory and control engineering.

<title>Three-dimensional device characterization by high-speed cinematography</title>

“…The main reasons for these difficulties are first the challenges presented by the speed and size of most microparts and second the fact, that the parts of interest are very often hidden within the devices with no access to get measurement data without altering the microdevice performance. Concerning the first item, the development of specialized highspeed and high-resolution measurement techniques is a strong demand in order to improve new types of actuators and to ease their commercialization [1]. The 3-D high-speed cinematography test stand presented in this work is part of this strategy.…”

Measuring the circular motion of small objects using laser stroboscopic images

“…According to literature, various noncontact methods have been developed, which can be classified based on the measurement principle as the optical-electronic method, the high-speed imaging method, and stroboscope imaging method. [1][2][3] In particular, the high-speed imaging method is widely used in the industry. It can measure repetitive or nonrepetitive, constant or variable speed motions by taking thousands of images per second.…”

The laser-scanning confocal vibrometer microscope

“…Laser-Doppler vibrometry is a widely used technique to measure the instantaneous velocity and deflection or, by employing FFT-analysis, the vibration spectrum on the measurement spot of a specimen. This technique is also used since a few years to analyze MEMS [1,2,3]. An existing system, introduced by Polytec in 2001, consists of a scanner unit that is attached on the C-mount of a standard microscope [4].…”