Sunday May 17, 2009 WorkShop sw-f1: Control Issues in the Micro/Nano-World


- Mathieu Grossard1, Nicolas Chaillet2 ,Mehdi Boukallel1, Arnaud Hubert2 and Christine Rotinat-Libersa1

1: Interactive Robotics Unit
CEA LIST,
Fontenay-aux-Roses, F-92265
France

2: Automatic Control and Micro-Mechatronic Systems (AS2M) department
FEMTO-ST Institute, UMR CNRS 6174 -UFC/ENSMM/UTBM,
24 rue Alain Savary, Besanšon, F-25000
France

Contact: mathieu.grossard 'at' cea 'dot' fr, mehdi.boukallel 'at' cea 'dot' fr

Title


Towards the mechanical and control-oriented optimization of micromechatronic systems for robust control

Abstract


When applying scale reduction to mechatronic systems that are usually encountered at the macroscale, the miniaturisation step necessarily implies functional integration of these systems. This general trend makes microsystems more and more functionally inte- grated, which makes them converging towards the adaptronic concept.

We developed a new optimal synthesis method of monolithic compliant structures to design integrated actuators. Our method is based on the optimal arrangement of flexible building blocks thanks to a multi-criteria genetic algorithm. These building blocks re- sult from the assembly of beam elements and are described by a finite element method. They can be either passive or active by exploiting the inverse piezoelectric effect, thus making realistic the integration of the actuation principle inside the mechanical structure.

In addition, a dynamic description of the input(s)-output(s) behavior of these flexible mechanisms can be taken into account in our optimization method. Thus, new fitness functions allow the optimal synthesis of devices within a wide schedule of conditions, which can guaranty some specific performances during the control process of these synthe- sized systems afterwards. Innovative control-based metrics are considered in the optimi- zation procedure to fit the open-loop frequency response of the automatically synthesized mechanisms. These last criteria have been drawn here to optimize modal controllability and observability of the smart compliant mechanisms, which is particularly interesting for the control of these flexible structures afterwards.

Finally, a monolithic piezoelectric microgripper prototype is optimally designed using our developed software tool. The experimental tests made can validate all the diefferent steps of our mechatronics design methodology, from the first designing step of the com- plete topology study to the final step of the robust control in close-loop form.

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