Semi-autonomous scheme for pushing micro-objects

-In many microassembly applications, it is often desirable to position and orient polygonal micro-objects lying on a planar surface. Pushing micro-objects using point contact provides more flexibility and less complexity compared to pick and place operation. Due to the fact that in micro-world surface forces are much more dominant than inertial forces and these forces are distributed unevenly, pushing through the center of mass of the micro-object will not yield a pure translational motion. In order to translate a micro-object, the line of pushing should pass through the center of friction. In this paper, a semi-autonomous scheme based on hybrid vision/force feedback is proposed to push microobjects with human assistance using a custom built telemicromanipulation setup to achieve pure translational motion. The pushing operation is divided into two concurrent processes: In one process human operator who acts as an impedance controller alters the velocity of the pusher while in contact with the micro-object through scaled bilateral teleoperation with force feedback. In the other process, the desired line of pushing for the micro-object is determined continuously using visual feedback procedures so that it always passes through the varying center of friction. Experimental results are demonstrated to prove nanoNewton range force sensing, scaled bilateral teleoperation with force feedback and pushing microobjects

Haptic feedback in teleoperation in Micro-and Nano-Worlds.

International audienceRobotic systems have been developed to handle very small objects, but their use remains complex and necessitates long-duration training. Simulators, such as molecular simulators, can provide access to large amounts of raw data, but only highly trained users can interpret the results of such systems. Haptic feedback in teleoperation, which provides force-feedback to an operator, appears to be a promising solution for interaction with such systems, as it allows intuitiveness and flexibility. However several issues arise while implementing teleoperation schemes at the micro-nanoscale, owing to complex force-fields that must be transmitted to users, and scaling differences between the haptic device and the manipulated objects. Major advances in such technology have been made in recent years. This chapter reviews the main systems in this area and highlights how some fundamental issues in teleoperation for micro- and nano-scale applications have been addressed. The chapter considers three types of teleoperation, including: (1) direct (manipulation of real objects); (2) virtual (use of simulators); and (3) augmented (combining real robotic systems and simulators). Remaining issues that must be addressed for further advances in teleoperation for micro-nanoworlds are also discussed, including: (1) comprehension of phenomena that dictate very small object (< 500 micrometers) behavior; and (2) design of intuitive 3-D manipulation systems. Design guidelines to realize an intuitive haptic feedback teleoperation system at the micro-nanoscale level are proposed

A Review of Haptic Feedback Teleoperation Systems for Micromanipulation and Microassembly

International audienceThis paper presents a review of the major haptic feedback teleoperation systems for micromanipulation. During the last decade, the handling of micrometer-sized objects has become a critical issue. Fields of application from material science to electronics demonstrate an urgent need for intuitive and flexible manipulation systems able to deal with small-scale industrial projects and assembly tasks. Two main approaches have been considered: fully automated tasks and manual operation. The first one require fully pre determined tasks, while the later necessitates highly trained operators. To overcome these issues the use of haptic feedback teleoperation where the user manipulates the tool through a joystick whilst feeling a force feedback, appears to be a promising solution as it allows high intuitiveness and flexibility. Major advances have been achieved during this last decade, starting with systems that enable the operator to feel the substrate topology, to the current state-of-the-art where 3D haptic feedback is provided to aid manipulation tasks. This paper details the major achievements and the solutions that have been developed to propose 3D haptic feedback for tools that often lack 3D force measurements. The use of virtual reality to enhance the immersion is also addressed. The strategies developed provide haptic feedback teleoperation systems with a high degree of assistance and for a wide range of micromanipulation tools. Based on this expertise on haptic for micromanipulation and virtual reality assistance it is now possible to propose microassembly systems for objects as small as 1 to 10 micrometers. This is a mature field and will benefit small-scale industrial projects where precision and flexibility in microassembly are required

Recent advances in the study of Micro/Nano Robotics in France.

International audienceIn France, during the last decade, significant research activities have been performed in the field of micro and nano robotics. Generally speaking the microrobotic field deals with the design, the fabrication and the control of microrobots and microrobotic cells. These microrobots are intended to perform various tasks in the so-called Microworld. The scale effects from macroworld to microworld deeply affect robots in the sense that new hard constraints appear as well as new manufacturing facilities. Concerning the nanorobotics, in order to achieve high-efficiency and three-dimensional nanomanipulation and nanoassembly, parallel imaging/manipulation force microscopy and three-dimensional manipulation force microscope, as well as nanmanipulation in the scanning electron microscope, have been developed. Manipulation of nanocomponents, such as nanoparticles, nanowires and nanotubes, have been addressed to build two-dimensional nano patterns and three-dimensional nano structure

Silicon end-effectors for microgripping tasks.

International audienceMicromanipulation is a key task to perform serial assembly of MEMS. The two-fingered microgrippers are usable but require specific studies to be able to work in the microworld. In this paper, we propose a new microgripping system where actuators and the end-effectors of the gripper are fabricated separately. End-effectors can thus be adapted to the manipulated micro-objects without new design and/or fabrication of the actuator. The assembly of the end-effectors on our piezoelectric actuators guarantee a great modularity for the system. This paper focuses on the original design, development and experimentation of new silicon end-effectors, compatible with our piezoelectric actuator. These innovative end-effectors are realized with the well known DRIE process and are able to perform micromanipulation tasks of objects whose typical size is between 5 μm and 1 mm

Overview of coupling effects on interaction forces in micro-nano-world.

International audienceThe release of object during robotic micromanipulation operations stays a challenge. The adhesion forces have to be known to improve micromanipulation tasks. Adhesion models build from macrophysics (continuum mechanics) or from nanophysics (atomic scale interactions) do not fit well experiments on the microscale. This is due to some phenomenon which are specific to the microphysics. Some of them are developed in this article. First, it is shown that the charges distributions observed on the microscale would have negligible effects on the nanoscale but disturbs significantly micromanipulation. Secondly, the impact of both chemical functionalisation and physical structuration of the surfaces on microscale are presented. Third, during the contact between two objects, the van der Waals forces induces significant local deformations on the microscale contrary to nanosclae where the deformation is negligible. This article shows some typical differences between microscale and nanoscale

Principle of a submerged freeze gripper for micro-assembly.

International audienceThe development of reliable and repeatable strategies to manipulate and assemble microobjects lies in the efficiency, reliability and precision of the handling processes. In this paper, we propose a thermal based microgripper working in an aqueous medium. Manipulating and assembling in liquid surroundings can indeed be more efficient than in dry conditions. A comparative analysis on the impact of dry and liquid media on surface forces, contact forces and the miniaturization of the system. hydrodynamic forces is shown. In addition, ice grippers represent flexible manipulation solutions. Nevertheless, when micromanipulation tasks are performed in air, capillary forces can drastically perturb the release. Our submerged freeze microgripper exploits the liquid surroundings to generate an ice droplet to catch microobjects, and to avoid capillary forces during the release. The thermal principle, the first microgripper prototype, an ice generation simulation, and the first tests are presented. The main objective is to validate the manipulation principle. Further works will be focused on control and optimization of the ice generation an

Analysis of forces for micromanipulations in dry and liquid media.

International audienceDuring microscale object manipulation, contact (pull-off) forces and non-contact (capillary, van der Waals and electrostatic) forces determine the behaviour of the micro-objects rather than the inertial forces. The aim of this article is to give an experimental analysis of the physical phenomena at a microscopic scale in dry and liquid media. This article introduces a review of the major differences between dry and submerged micromanipulations. The theoretical influences of the medium on van der Waals forces, electrostatic forces, pull-off forces and hydrodynamic forces are presented. Experimental force measurements based on an AFM system are carried out. These experiments exhibit a correlation better than 40 % between the theoretical forces and the measured forces (except for pull-off in water). Finally, some comparative experimental micromanipulation results are described and show the advantages of the liquid medium

A submerged freeze microgripper for micromanipulations.

International audienceEfficient, reliable and flexible handling is still very challenging in micromanipulation and micro-assembly. In this paper, we propose an original thermally actuated gripper based on the use of ice to manipulate submerged artificial micro-objects sized under 100 µm. Manipulating in liquid surroundings can indeed be more interesting than in dry conditions. A comparative analysis on the impact of dry and liquid media on surface forces, contact forces and hydrodynamic forces shortly given first shows it. Concerning the use of ice for micromanipulation, cryogenic grippers are a flexible solution. Nevertheless, as they currently work in air, water must be provided by an external device and capillary force occurs during the release. Our submerged freeze microgripper takes advantages of the aqueous surroundings for the handling process as explained. Ther thermal principle, based on the Peltier effect, the characteristics of the microgripper prototype and the first micromanipulation tests are also presented