Design, fabrication and characterization of a flexible system based on thermal glue for in AIR and in SEM microassembly.

International audienceThis paper presents the design, fabrication and characterization of a device able to exchange the tip part (so-called the tools) of a two fingered microgripper. The principle of this tool changer is based on the use of a thermal glue whose state (liquid or solid) is changed by heating or cooling. Several kinds of pairs of tools have been designed. The suitable pair of tools can be chosen according to the size, shape and material of the object to manipulate. The tool changer enables one to perform a sequence of elementary micromanipulation tasks (i.e. an assembly sequence) by using only one gripper mounted on only one manipulator. The tool changer has been automated and successfully tested in air and in the vacuum chamber of a Scanning Electron Microscope (SEM). It brings flexibility to the micromanipulation cell and contributes to reduce the costs, the used space and experimentations time for micromanipulations in the SEM. The assembly of a ball bearing (the balls are 200 ¹m in diameter) has been successfully tested using the microgripper equipped with the tool changer in a SEM. This tool changer has been designed for a microgripper but can be easily adapted to lots of other kinds of systems

Flexible micro-assembly system equiped with an automated tool changer.

International audienceThis paper deals with the design, fabrication and experimental validation of several modules of a micro-assembly system. On one hand, a microgripper is integrated in a four degrees of freedom system. On the other hand, a tool changer is designed. It enables to exchange automatically the tip part of the microgripper and then dedicated tools can be used to achieve specific tasks. The principle of this tool changer relies on a thermal glue whose phase (liquid or solid) is controlled by heat generators. This system is based on the modeling of thermal phenomena in the tools during a cycle of tool exchange. A compliant system is added to limit micromanipulation forces applied during assembly tasks like insertions. Finally, the successful assembly of several microcomponents is detailed, highlighting the capabilities and benefits of the whole system

A micromanipulation cell including a microtools changer.

International audienceThis paper describes the structure of a flexible micromanipulation cell designed to perform precise pick and place operations of objects with typical sizes from 20 to 500 ¹m. This cell is composed of three linear stages (X-Y-Z), a four degrees of freedom microgripper and a microtools changer

Modeling, Identification and Control of a Thermal glue based temporary fixing system : Application to the Micro-Robotic field.

International audienceThe purpose of this paper is to present a temporary fixing system based on a thermal glue that is well-adapted to micro-robotics. In the paper, ths system is used to design a tool changer but can be generalized to other micro-robotic applications. A thermal modeling and an identification procedure are presented to propose a strategy to control the system. This system takes place into a micromanipulation station to gain flexibility, space and complexity. Indeed, to perform sequences of micromanipulation tasks (i.e. micro-assembly sequences), only one manipulator, able to use sequentially several end-effectors, has to be used instead of several dedicated to one specific task

Temporary fixing systems for applications in Microrobotics.

International audienceThis paper focuses on temporary fixing systems for microrobotics. Several solutions from the art are presented and compared : solutions based on mechanical bending, electromagnetic elements, electrostatic forces, glues, polymers or Van der Waals forces. From this analysis, we designed and developed a new system based on thermal glue (that permits to exchange the tip part of a microgripper) for microassembly stations. This system brings a high flexibility and compactness for microrobotic applications

Workshop on "Robotic assembly of 3D MEMS".

Proceedings of a workshop proposed in IEEE IROS'2007.The increase of MEMS' functionalities often requires the integration of various technologies used for mechanical, optical and electronic subsystems in order to achieve a unique system. These different technologies have usually process incompatibilities and the whole microsystem can not be obtained monolithically and then requires microassembly steps. Microassembly of MEMS based on micrometric components is one of the most promising approaches to achieve high-performance MEMS. Moreover, microassembly also permits to develop suitable MEMS packaging as well as 3D components although microfabrication technologies are usually able to create 2D and "2.5D" components. The study of microassembly methods is consequently a high stake for MEMS technologies growth. Two approaches are currently developped for microassembly: self-assembly and robotic microassembly. In the first one, the assembly is highly parallel but the efficiency and the flexibility still stay low. The robotic approach has the potential to reach precise and reliable assembly with high flexibility. The proposed workshop focuses on this second approach and will take a bearing of the corresponding microrobotic issues. Beyond the microfabrication technologies, performing MEMS microassembly requires, micromanipulation strategies, microworld dynamics and attachment technologies. The design and the fabrication of the microrobot end-effectors as well as the assembled micro-parts require the use of microfabrication technologies. Moreover new micromanipulation strategies are necessary to handle and position micro-parts with sufficiently high accuracy during assembly. The dynamic behaviour of micrometric objects has also to be studied and controlled. Finally, after positioning the micro-part, attachment technologies are necessary

Development, modelling and control of a micro/nano positioning 2DoF stick-slip device.

International audienceThe works presented in this article are motivated by the high performances required in micromanipulation/ microassembly tasks. For that, this paper presents the developement, the modelling and the control of a 2 degrees of freedom (in linear and angular motion) micropositioning device. Based on the stick-slip motion principle, the device is characterized by unlimited strokes and submicrometric resolutions. First, experiments were carried out to characterize the performances of the micropositioning device in resolution and in speed. After that, a state-space model was developed for the sub-step functioning. Such functioning is interesting for a highly accurate task like nanopositioning. The model is validated experimentally. Finally, a controller was designed and applied to the micropositioning device. The results show good robustness margins and a response time of the closed-loop system

Modular architecture of the microfactories for automatic micro-assembly.

International audienceThe construction of a new generation of MEMS which includes micro-assembly steps in the current microfabrication process is a big challenge. It is necessary to develop new production means named micromanufacturing systems in order to perform these new assembly steps. The classical approach called “top-down” which consists in a functional analysis and a definition of the tasks sequences is insufficient for micromanufacturing systems. Indeed, the technical and physical constraints of the microworld (e.g. the adhesion phenomenon) must be taken into account in order to design reliable micromanufacturing systems. A new method of designing micromanufacturing systems is presented in this paper. Our approach combines the general “top-down” approach with a “bottom-up” approach which takes into account technical constraints. The method enables to build a modular architecture for micromanufacturing systems. In order to obtain this modular architecture, we have devised an original identification technique of modules and an association technique of modules. This work has been used to design the controller of an experimental robotic micro-assembly station