Development of a micromanipulation system with force sensing

This article provides in-depth knowledge about our undergoing effort to develop an open architecture micromanipulation system with force sensing capabilities. The major requirement to perform any micromanipulation task effectively is to ensure the controlled motion of actuators within nanometer accuracy with low overshoot even under the influence of disturbances. Moreover, to achieve high dexterity in manipulation, control of the interaction forces is required. In micromanipulation, control of interaction forces necessitates force sensing in milli-Newton range with nano-Newton resolution. In this paper, we present a position controller based on a discrete time sliding mode control architecture along with a disturbance observer. Experimental verifications for this controller are demonstrated for 100, 50 and 10 nanometer step inputs applied to PZT stages. Our results indicate that position tracking accuracies up to 10 nanometers, without any overshoot and low steady state error are achievable. Furthermore, the paper includes experimental verification of force sensing within nano-Newton resolution using a piezoresistive cantilever endeffector. Experimental results are compared to the theoretical estimates of the change in attractive forces as a function of decreasing distance and of the pull off force between a silicon tip and a glass surface, respectively. Good agreement among the experimental data and the theoretical estimates has been demonstrated

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

Automatic pick-and-place of 40 microns objects using a robotic platform.

International audienceRobotic micro-assembly is one way to manufacture new generation of out of plane and/or hybrid microsystems. This approach requires the study of micromanipulation strategies adapted to the microworld and especially to the surface and adhesion forces. We are focusing our works on the study of robotic assembly methods applied to objects whose size is below 100 micrometers. The handling strategy used is based on a two fingered gripper. In order to reduce the adhesion between the gripper and the manipulated objects specific end-effectors have been developed. Moreover, to improve the release reliability we are using a polymer substrate which induces high adhesion with the objet. Some automatic pick-and-places on objects whose typical size is 40 micrometers have been done (cycle time of 1.8 second). There show the reliability of the proposed approach

Robotic Micro-assembly of microparts using a piezogripper.

International audienceThis paper deals with robotic micro-assembly of silicon micro-objects whose sizes are tens of micrometers. This production means is one of a more promising approach to realize 3D and/or hybrid microsystems. Current works in robotic micro-assembly are focused on the assembly of microobjects on a large substrate. We are focusing in the study of micro-parts assembly to build microscopic subsystems usable in larger products. This approach requires specific functionalities like a ‘micro-vise' required to block the first object during assembly. Original strategies are proposed and applied on an experimental robotic structure composed of micropositionning stages, videomicroscopes, piezogripper, and silicon endeffectors. Some experimental teleoperated micro-assemblies has validated the proposed methods and the reliability of the principles. Future works will be focused on micro-assembly automation

Control of Adhesion using Surface Functionalisations for Robotic Microhandling.

International audienceRobotic microhandling is a promising way to assemble microcomponents in order to manufacture new generation of Hybrid Micro ElectroMechanical Systems (HMEMS). However, at the scale of several micrometers, adhesion phenomenon highly perturbs the micro-objects release and the positioning. This phenomenon is directly linked to both the object and the gripper surface mechanical and chemical properties. The control of the adhesion properties requires multidisciplinary approaches including roughness control, mechanical properties control and chemical surface functionalisation. We propose to control adhesion by using chemical surface functionalisations by intrinsic conducting polymer electrodeposition or Self-Assembly Monolayer (SAM) and using surface structuration

Trapping/Pinning of colloidal microspheres over glass substrate using surface features

Suspensions of micro and nano particles made of Polystyrene, Poly(methyl methacrylate), Silicon dioxide etc. have been a standard model system to understand colloidal physics. . These systems have proved useful insights into phenomena such as self-assembly. Colloidal model systems are also extensively used to simulate many condensed matter phenomena such as dynamics in a quenched disordered system and glass transition. A precise control of particles using optical or holographic tweezers is essential for such studies. However, studies of collective phenomena such as jamming and flocking behaviour in a disordered space are limited due to the low throughput of the optical trapping techniques.In this article, we present a technique where we trap and pin polystyrene microspheres ~ 10 {\mu}m over triangular-crest shaped microstructures in a microfluidic environment. Trapping/Pinning occurs due to the combined effect of hydrodynamic interaction and non-specific adhesion forces. This method allows trapping and pinning of microspheres in any arbitrary pattern with a high degree of spatial accuracy which can be useful in studying fundamentals of various collective phenomena as well as in applications such as bead detachment assay based biosensors

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

Microdevices and Microsystems for Cell Manipulation

Microfabricated devices and systems capable of micromanipulation are well-suited for the manipulation of cells. These technologies are capable of a variety of functions, including cell trapping, cell sorting, cell culturing, and cell surgery, often at single-cell or sub-cellular resolution. These functionalities are achieved through a variety of mechanisms, including mechanical, electrical, magnetic, optical, and thermal forces. The operations that these microdevices and microsystems enable are relevant to many areas of biomedical research, including tissue engineering, cellular therapeutics, drug discovery, and diagnostics. This Special Issue will highlight recent advances in the field of cellular manipulation. Technologies capable of parallel single-cell manipulation are of special interest