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

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.