Interval techniques and control theory tools for linear modeling and control of microassembly and micromanipulation systems
Calcul par intervalles et outils de l’automatique permettant la micromanipulation à précision qualifiée pour le microassemblage
Résumé
Micromechatronic systems integrate in a very small volume functions with different natures. The trend towards miniaturization and complexity of functions to achieve leads to 3-dimensional microsystems. These 3-dimensional systems are formed by microrobotic assembly of various microfabricated and incompatible components. To achieve the assembly operations with high accuracy and high resolution, adapted sensors for the
microworld and special tools for the manipulation are required. The microactuators are the main elements that constitute the micromanipulation systems. These actuators are often based on smart materials, in particular piezoelectric materials. The piezoelectric materials are characterized by their high resolution (nanometric), large bandwidth (more than kHz) and high force density. This why the piezoelectric actuators are widely used in the micromanipulation and microassembly tasks. However, the behavior of the piezoelectric actuators is non-linear and very sensitive to the environment. Moreover, the developpment of the micromanipulation and the microassembly tasks is limited by the lack of precise and compatible sensors with the microworld dimensions. In the presence of the difficulties related to the sensors realization and the complex characteristics of the actuators, it is difficult to obtain the required performances for the micromanipulation and the microassembly tasks. For that, it is necessary to develop a specific control
approach that achieves the wanted accuracy and resolution. The works in this thesis deal with this problematic. In order to success the micro-
manipulation and the microassembly tasks, robust control approaches such as H ∞ have already been tested to control the piezoelectric actuators. However, the main drawbacks of these methods is the derivation of high order controllers. In the case of embedded microsystems, these high order controllers are time consuming which limit their embedding possibilities. To address this problem, we propose in our work an alternative solution
to model and control the microsystems by combining the interval techniques with the automatic tools. We will also seek to show that the use of these techniques allows to derive robust and low-order controllers