Novel actuators

Several new actuator technologies (e.g. linear electrical actuators and morphing composite materials) are coming to market and offer the potential for improving the fidelity and scope of dynamic earthquake engineering testing. The overall aim of this joint research activity is to evaluate this potential and to position the laboratories in this project so that they can offer users better experimental opportunities through these technologies. This activity is divided in three linked tasks.

The first task will produce a state-of-the-art review of the performance requirements for earthquake engineering testing, reviewing current testing practice and examples as well as envisioning new kinds of testing that might be enabled by the new technologies. Information will be collated about the types and purposes of experiment, typical configurations and performance requirements, advantages and pit-falls, techniques for performance enhancement and optimisation, and reference publications, etc.

The second task aims at identifying and classifying candidate actuator technologies that might satisfy these performance requirements and then at evaluating a small number of these through desk studies and simple laboratory prototypes. The detailed technical evaluation of the new technologies will be matched with the identified performance requirements so as to guide the assessment of whether the devices could provide a useful extension to existing test methods or offer a realistic chance of enabling new types of test. The next stage will be to select one or two technologies (in additional to the pre-selected linear electrical actuator technology) and to build a simple test-bed for each technology to assess the performance of the system and to identify any problems.

The final task foresees the prototype design study for a hybrid actuation system that combines linear servo-hydraulic actuators with linear electrical actuators, with the aim of the latter improving the high-frequency fidelity of the former. The purpose is to understand fully the potential of this system as a means of improving conventional actuation systems to meet the requirements of advanced shaking table and reaction wall testing on large structures. A further objective will be to extend the actual control scheme by developing and implementing real-time, multi-processor schemes ensuring accurate synchronization, high reliability, total safety and easy debugging and maintenance.

Actuators Workshop, Iasi (RO), July 2009

Released Deliverables on Novel Actuators
WP12 Report on performance requirements of actuation systems for shaking table or pseudo-dynamic testing (.pdf, 1.05 Mb)
This report provides a state-of-the-art review of the performance requirements of typical earthquake engineering actuation devices employed by the large testing laboratories throughout Europe. The performance requirements were compiled through a combination of structured questionnaires using an existing on-line survey system at UNIVBRIS and a dedicated day in the first (2009) SERIES workshop. The needs of the earthquake engineering community that are not currently met by available actuation devices have been explored. User opinions have been investigated in relation to performance enhancement and optimisation solutions for hydraulic, electrical and hybrid actuation devices in order to expand the experimental capabilities and meet more sophisticated test needs in the future.
WP12 Report on evaluation of novel actuation systems for shaking table, Pseudo-dynamic or field testing (.pdf, 4.31Mb)
This report presents studies into novel forms of actuation technology, aimed at enhancing the responsiveness and controllability of actuators, particularly to extend their performance at higher frequencies. Several improvements to servo-hydraulic test systems are proposed including: a novel dual manifold servalve, a directly controlled piezoservovalve; a novel hybrid actuator in which piezo-actuators are positioned within the cylinder of a servo-hydraulic actuator; and an asymmetric tandem actuator which reduces energy demand for fatigue testing. As an alternative to servo-hydraulic systems, two types of linear electric actuator have been trialled; these are promising, but are currently limited to relatively low load capacities. A higher capacity electric actuator (maximum dynamic load 130 kN) has been specified and is currently under construction.
WP12 Prototype design study (.pdf, 2.6Mb) This report presents prototypes and implementation studies aiming to improve the performances of typical earthquake engineering actuation systems employed by the large testing laboratories throughout Europe. We target both the improvement of conventional actuation systems and control architecture with the scope to extend the applicability of the dynamic and pseudo-dynamic testing methods.


What's next

Series logo small   SERIES Concluding Workshop
  Joint with US-NEES "Earthquake Engineering Research Infrastructures

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