Motion Planning for Kinematic systems

In this paper, we present a general theory of motion planning for kinematic systems. This theory has been developed for long by one of the authors in a previous series of papers. It is mostly based upon concepts from subriemannian geometry. Here, we summarize the results of the theory, and we improve on, by developping in details an intricated case: the ball with a trailer, which corresponds to a distribution with flag of type 2,3,5,6. This paper is dedicated to Bernard Bonnard for his 60th birthday

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

Modeling the trajectory of a microparticle in a dielectrophoresis device.

International audienceMicro- and nanoparticles can be trapped by a nonuniform electric field through the effect of the dielectrophoretic principle. Dielectrophoresis DEP is used to separate, manipulate, and detect microparticles in several domains, such as in biological or carbon nanotube manipulations. Current methods to simulate the trajectory of microparticles under a DEP force field are based on finite element model FEM, which requires new simulations when electrode potential is changed, or on analytic equations limited to very simple geometries. In this paper, we propose a hybrid method, between analytic and numeric calculations and able to simulate complex geometries and to easily change the electrode potential along the trajectory. A small number of FEM simulations are used to create a database, which enables online calculation of the object trajectory as a function of electrode potentials

Modeling and control of non-contact micromanipulation based on dielectrophoresis.

International audienceMicro and nano-particles can be trapped by a non uniform electric field through the effect of the dielectrophoretic force. Dielectrophoresis (DEP) is used to separate, manipulate and sense micro particles in several domains, such as in biological or Carbon Nano-Tubes (CNTs) manipulations. This paper tackles the creation of a closed loop strategy in order to control, using DEP, the trajectory of micro objects using vision feedback. A modeling of the dielectrophoresis force is presented to illustrate the non linearity of the system and the high dynamics of the object under dielectrophoresis . A control strategy based on the generalized predictive control method is proposed with the aim of controlling the trajectory, taking advantage of the high dynamics despite the non linearity. Simulated results are shown to evaluate our control strategy

Open loop control of dielectrophoresis non contact manipulation.

International audienceThe framework of this paper is the study of "No Weight Robots-NWR" that use non-contact transmission of movement (e.g. dielectrophoresis) to manipulate micro-objects enabling significant throughput (1Hz). Dielectrophoresis (DEP) is currently used to separate, manipulate and detect micro particles in several domains with high speed and precision, such as in biological cell or Carbon Nano-Tubes (CNTs) manipulations. A dielectrophoresis system can also be considered as a robotic system whose inputs are the voltages of the electrodes and output is the object trajectory. This "No Weight Robots" enables the positionning of the manipulted object in a 3D space. This paper is summarized the modeling principle of this new type of robots and some first results on trajectory control in 2D space

Dynamic modelling of a submerged freeze microgripper using a thermal network.

International audienceManipulating micro-objects whose typical size is under 100 µm becomes an interesting research topic for micro-assembly applications. A comparative analysis of dry and liquid media impacts on surface forces, contact forces and hydrodynamic forces showed that performing manipulation and assembly in liquid surroundings can indeed be more efficient than in dry conditions. We propose a thermal based micromanipulator designed to operate completely submerged in an aqueous medium. The handling principle and the advantages of our proposed submerged freeze microgripper against air working cryogenic grippers are first described. Then, the thermal principle based on Peltier effect, the characteristics of the prototype, and its first micromanipulation tests are reported. In order to manage the heat exchanges in the microgripper, a dynamic thermal model using electrical analogy has been developed for a 3D heat sink of the microgripper. Its validation is presented in the last section.Further works will be focused on the characterization of all parameters and its experimental validation

Principle of a submerged freeze microgripper.

International audienceManipulating microscopic objects still remains a very challenging task. In this paper, we propose a freeze microgripper working in an innovative environment, i.e. liquid medium.We first review a comparative analyse of the influences of dry and liquid media on contact and non contact forces. It clearly shows the interest of the liquid medium. A survey of different microhandling systems based on the use of ice is also given. The proposed submerged microgripper exploits the liquid surroundings to generate an ice microvolume as an active end-effector. Its principle based on Peltier effect is described and the physical characteristics of the prototype are detailed. We present the results of the numerical modelling of the prototype developed. Experimentations validate the thermal principle. Using it for micromanipulation tasks is the purpose of further work

Dynamic modelling for a submerged freeze microgripper using thermal networks.

International audienceThe growing interest for micromanipulation systems requires efficient, reliable and flexible handling strategies. Recent studies have demonstrated that performing manipulations and assembly in liquid surroundings is more advantageous than in dry conditions, especially when objects are under 100 μm in size. The thermally actuated ice microgripper proposed and analysed in this paper is designed to operate in a completely submerged manner in an aqueous medium. The handling principle which benefits from adhesive properties of ice, its thermal control principle based on Peltier effect, some features of the prototype, and the first micromanipulation tests are summarized. This paper is focused on the modelling of the thermal microhandling system using electrical analogy. The submerged microgripper is split into different subsystems which are studied in order to identify their thermal network. Then they are interconnected to build the whole thermal network of the submerged microgripper. This model is validated by comparison with experimental measurements. Controlling the temperatures involved in our device will be the purpose of further works