Modular robotic platform for silicon micromechanical assembly.

International audienceAs no reliable methods is available to manipulate component whose typical size is up to 100μm, current industrial assembled products contained only components down to this physical limit. In that scale, micro-assembly requires specific handling strategies to overcome adhesion and high precision robots. This paper deals with an original robotic system able to perform reliable micro-assembly of silicon microobjects whose sizes are tens of micrometers. Original hybrid handling strategies between gripping and adhesion handling are proposed. An experimental robotic structure composed of micropositionning stages, videomicroscopes, piezogripper, and silicon end-effectors is presented. A modular control architecture is proposed to easily design and modify the robotic structure. Some experimental teleoperated micromanipulations and micro-assemblies have validated the proposed methods and the reliability of the principles. Future works will be focused on micro-assembly automation

Distributed manipulation by controlling force fields through arrays of actuators

Tato práce se zaměřuje na řízení distribuované manipulace prostřednictvím fyzikálních polí vytvářených maticí akčních členů. Práce se zabývá především manipulací s objekty pomocí nehomogenního elektrického a magnetického pole - dielektroforézou a magnetoforézou. Pro oba principy jsou odvozeny matematické modely vhodné pro začlenění do zpětnovazební řídicí smyčky. Modely mají v obou doménách podobnou strukturu, která dovoluje vývoj jednotného řídicího systému. Nelineární model dynamiky systému je v každé vzorkovací periodě invertován pomocí numerického řešení optimalizačního problému. Výhodou navržené strategie řízení je, že dovoluje paralelní manipulaci - nezávislou manipulaci s několika objekty najednou. Práce vedle teoretických konceptů popisuje také technické detaily experimentálních platforem spolu s výsledky mnoha experimentů. Pro dielektroforézu je navrženo nové uspořádání elektrod, které umožňuje manipulaci s více objekty v rovině a zároveň vyžaduje pouze jednovrstvou výrobní technologii. Na algoritmické straně práce představuje nové použití fázové modulace napětí pro řízení dielektroforézy. Dále také popisuje součásti vyvinuté instrumentace, jako jsou vícekanálové generátory pro řízení dielektroforézy prostřednictvím amplitudové a fázové modulace a optické měření polohy v reálném čase pomocí senzoru bez objektivu. Pro magnetoforézu je detailně popsána modulární experimentální platforma sestávající se z pole cívek se železnými jádry. Díky modularitě může být platforma použita k ověření nejen centralizovaných, ale také distribuovaných řídicích systémů.This work focuses on the control of distributed manipulation through physical fields created by arrays of actuators. In particular, the thesis addresses manipulation of objects using non-uniform electric and magnetic fields---dielectrophoresis and magnetophoresis, respectively. In both domains, mathematical models suitable for incorporation into a feedback control loop are derived. The models in the two domains exhibit a similar structure, which encourages the development of a unified approach to control. The nonlinear model of the system dynamics is inverted by solving a numerical optimization problem in every sampling period. A powerful attribute of the proposed control strategy is that a parallel manipulation---the simultaneous and independent manipulation of several objects---can be demonstrated. Besides the theoretical concepts, the thesis also describes technical details of experimental platforms for both physical domains, together with outcomes from numerous experiments. For dielectrophoresis, a new layout of electrodes is documented that allows full planar manipulation while requiring only a one-layer fabrication technology. On the algorithmic side, work presents a novel use of phase modulation of the voltages to control dielectrophoresis. Dedicated instrumentation is also discussed in the thesis such as multichannel generators for control of dielectrophoresis through amplitude and phase modulation and optical real-time position measurements using common optics and a lensless sensor. For magnetophoresis, a modular test bed composed of a planar array of coils with iron cores is described in detail. Thanks to the modularity, the platform can be used for verification of not only the centralized but also distributed control strategies

Optimizing polymer lab-on-chip platforms for ultrasonic manipulation: Influence of the substrate

The choice of substrate material in a chip that combines ultrasound with microfluidics for handling biological and synthetic microparticles can have a profound effect on the performance of the device. This is due to the high surface-to-volume ratio that exists within such small structures and acquires particular relevance in polymer-based resonators with 3D standing waves. This paper presents three chips developed to perform particle flow-through separation by ultrasound based on a polymeric SU-8 layer containing channelization over three different substrates: Polymethyl methacrylate (PMMA); Pyrex; and a cracked PMMA composite-like structure. Through direct observations of polystyrene microbeads inside the channel, the three checked chips exhibit their potential as disposable continuous concentration devices with different spatial pressure patterns at frequencies of resonance close to 1 Mhz. Chips with Pyrex and cracked PMMA substrates show restrictions on the number of pressure nodes established in the channel associated with the inhibition of 3D modes in the solid structure. The glass-substrate chip presents some advantages associated with lower energy requirements to collect particles. According to the results, the use of polymer-based chips with rigid substrates can be advantageous for applications that require short treatment times (clinical tests handling human samples) and low-cost fabrication. © 2015 by the authors; licensee MDPI, Basel, Switzerland.The study has been performed in the framework of two Spanish National Research Project BIO2011-30535-C04-01,02,03, “Development of a high throughput for isolation of tumor cells circulating in peripheral blood”.We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer Reviewe

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

Real-time optimization-based control for dielectrophoresis

Tato práce popisuje návrh řízení pro bezkontaktní manipulaci s mikro- a mezoskopickými objekty pomocí dielektroforézy. Konkrétně je dokumentován výchozí stav systému založeného na optimalizaci v reálném čase. Řešený problém je dále rozšířen tak, aby byly umožněny současné změny amplitud a fázových posunů napěťových signálů použitých k ovládání. Pro řešení dané optimalizační úlohy je zvolena vhodná numerická metoda a systém je experimentálně ověřen. Použita jsou dvě různá elektrodová pole umožňující pohyb po přímce a v ploše. Dále jsou analyzovány a řešeny problémy spojené se škálovatelností systému, jako jsou rostoucí výpočetní nároky a vzájemné silové působení částic.This thesis describes the control design for a noncontact manipulation of micro- and mesoscale objects utilizing the dielectrophoresis. Specifically, the currently available system based on an optimization in real-time is documented. The optimization problem is further extended so that changes in both the amplitudes and the phase shifts of the voltage signals are used for actuation. A suitable numerical solver is chosen for the given optimization task and the system is experimentally verified. The two different electrode arrays allowing linear and planar motion are used. Furthermore, the issues related to the system scalability, such as the growing computational demands and mutual particle force interactions, are analyzed and appropriate solutions proposed

A Magnetically and Electrically Powered Hybrid Micromotor in Conductive Solutions: Synergistic Propulsion Effects and Label-Free Cargo Transport and Sensing

Electrically powered micro- and nanomotors are promising tools for in-vitro single-cell analysis. In particular, single cells can be trapped, transported and electroporated by a Janus particle (JP) using an externally applied electric field. However, while dielectrophoretic (DEP)-based cargo manipulation can be achieved at high-solution conductivity, electrical propulsion of these micromotors becomes ineffective at solution conductivities exceeding 0.3mS/cm. Here, we successfully extended JP cargo manipulation and transport capabilities to conductive near-physiological (<6mS/cm) solutions by combining magnetic field-based micromotor propulsion and navigation with DEP-based manipulation of various synthetic and biological cargos. Combination of a rotating magnetic field and electric field resulted in enhanced micromotor mobility and steering control through tuning of the electric field frequency. conditions are necessary. In addition, we demonstrated the micromotors ability of identifying apoptotic cell among viable and necrotic cells based their dielectrophoretic difference, thus, enabling to analyze the apoptotic status in the single cell samples for drug discovery, cell therapeutics and immunotherapy. We also demonstrated the ability to trap and transport live cells towards regions containing doxorubicin-loaded liposomes. This hybrid micromotor approach for label-free trapping, transporting and sensing of selected cells within conductive solutions, opens new opportunities in drug delivery and single cell analysis, where close-to-physiological medi

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

Advances in colloidal manipulation and transport via hydrodynamic interactions

In this review article, we highlight many recent advances in the field of micromanipulation of colloidal particles using hydrodynamic interactions (HIs), namely solvent mediated long-range interactions. At the micrsocale, the hydrodynamic laws are time reversible and the flow becomes laminar, features that allow precise manipulation and control of colloidal matter. We focus on different strategies where externally operated microstructures generate local flow fields that induce the advection and motion of the surrounding components. In addition, we review cases where the induced flow gives rise to hydrodynamic bound states that may synchronize during the process, a phenomenon essential in different systems such as those that exhibit self-assembly and swarming

Design and Implementation of Electromagnetic Actuation System to Actuate Micro/NanoRobots in Viscous Environment

The navigation of Micro/Nanorobots (MNRs) with the ability to track a selected trajectory accurately holds significant promise for different applications in biomedicine, providing methods for diagnoses and treatments inside the human body. The critical challenge is ensuring that the required power can be generated within the MNR. Furthermore, ensuring that it is feasible for the robot to travel inside the human body with the necessary power availability. Currently, MNRs are widely driven either by exogenous power sources (light energy, magnetic fields, electric fields, acoustics fields, etc.) or by endogenous energy sources, such as chemical interaction energy. Various driving techniques have been established, including piezoelectric as a driving source, thermal driving, electro-osmotic force driven by biological bacteria, and micro-motors powered by chemical fuel. These driving techniques have some restrictions, mainly when used in biomedicine. External magnetic fields are another potential power source of MNRs. Magnetic fields can permeate deep tissues and be safe for human organisms. As a result, magnetic fields’ magnetic forces and moments can be applied to MNRs without affecting biological fluids and tissues. Due to their features and characteristics of magnetic fields in generating high power, they are naturally suited to control the electromagnetically actuated MNRs in inaccessible locations due to their ability to go through tiny spaces. From the literature, it can be inferred from the available range of actuation technologies that magnetic actuation performs better than other technologies in terms of controllability, speed, flexibility of the working environment, and far less harm may cause to people. Also, electromagnetic actuation systems may come in various configurations that offer many degrees of freedom, different working mediums, and controllability schemes. Although this is a promising field of research, further simulation studies, and analysis, new smart materials, and the development and building of new real systems physically, and testing the concepts under development from different aspects and application requirements are required to determine whether these systems could be implemented in natural clinical settings on the human body. Also, to understand the latest development in MNRs and the actuation techniques with the associated technologies. Also, there is a need to conduct studies and comparisons to conclude the main research achievements in the field, highlight the critical challenges waiting for answers, and develop new research directions to solve and improve the performance. Therefore, this thesis aims to model and analyze, simulate, design, develop, and implement (with complete hardware and software integration) an electromagnetic actuation (EMA) system to actuate MNRs in the sixdimensional (6D) motion space inside a relatively large region of interest (ROI). The second stage is a simulation; simulation and finite element analysis were conducted. COMSOL multi-physics software is used to analyze the performance of different coils and coil pairs for Helmholtz and Maxwell coil configurations and electromagnetic actuation systems. This leads to the following.: • Finite element analysis (FEA) demonstrates that the Helmholtz coils generate a uniform and consistent magnetic field within a targeted ROI, and the Maxwell coils generate a uniform magnetic gradient. • The possibility to combine Helmholtz and Maxwell coils in different space dimensions. With the ability to actuate an MNR in a 6D space: 3D as a position and 3D as orientation. • Different electromagnetic system configurations are proposed, and their effectiveness in guiding an MNR inside a mimicked blood vessel environment was assessed. • Three pairs of Helmholtz coils and three pairs of coils of Maxwell coils are combined to actuate different size MNRs inside a mimicked blood vessel environment and in 6D. Based on the modeling results, a magnetic actuation system prototype that can control different sizes MNRs was conceived. A closed-loop control algorithm was proposed, and motion analysis of the MNR was conducted and discussed for both position and orientation. Improved EMA location tracking along a chosen trajectory was achieved using a PID-based closed-loop control approach with the best possible parameters. Through the model and analysis stage, the developed system was simulated and tested using open- and closed-loop circumstances. Finally, the closedloop controlled system was concluded and simulated to verify the ability of the proposed EMA to actuate an MN under different trajectory tracking examples with different dimensionality and for different sizes of MNRs. The last stage is developing the experimental setup by manufacturing the coils and their base in-house. Drivers and power supplies are selected according to the specifications that actuate the coils to generate the required magnetic field. Three digital microscopes were integrated with the electromagnetic actuation system to deliver visual feedback aiming to track in real-time the location of the MNR in the 6D high viscous fluidic environment, which leads to enabling closed-loop control. The closed-loop control algorithm is developed to facilitate MNR trajectory tracking and minimize the error accordingly. Accordingly, different tests were carried out to check the uniformity of the magnetic field generated from the coils. Also, a test was done for the digital microscope to check that it was calibrated and it works correctly. Experimental tests were conducted in 1D, 2D plane, and 3D trajectories with two different MNR sizes. The results show the ability of the proposed EMA system to actuate the two different sizes with a tracking error of 20-45 µm depending on the axis and the size of the MNR. The experiments show the ability of the developed EMA system to hold the MNR at any point within the 3D fluidic environment while overcoming the gravity effects. A comparison was made between the results achieved (in simulation and physical experiments) and the results deduced from the literature. The comparison shows that the thesis’s outcomes regarding the error and MNR size used are significant, with better performance relative to the MNR size and value of the error

On acoustic particle and cell manipulation in microfluidic systems

The combination of laminar flows in microfabricated channels and acoustic forces induced in ultrasonic standing wave fields offers new possibilities for advanced particle and cell manipulation in lab-on-a-chip applications as well as in relatively high throughput applications. Acoustic particle manipulation systems can be used e.g. to separate, wash, sort, trap or distribute particles in microfluidic networks. This doctoral thesis starts by reviewing the fundamental fields of study needed to realize such systems and to understand their potential impact. Next, the design, fabrication, operation and performance of a number of systems, based on system design principle termed the "Lund method", are described. The developed methods comprise a toolbox of generic particle handling methods that can be combined or used separately to handle biological and non-biological particles in liquid suspension. The toolbox is applied to solve various blood component handling tasks, e.g. separation of lipid particles and other contaminating substances from red blood cells and preparation of blood components. The results imply that it is possible to save thousands of people from brain damage caused by lipid particles each year, to reduce the strain on the blood banks significantly and to offer new methods for routine blood component handling. Several other important areas of application, where micrometer sized particles are routinely handled, can also be identified. Microscale acoustic particle manipulation technology is still in its infancy but, based on the findings presented in this thesis and by other researchers, it can be anticipated that new laboratory and industrial standards may very well emerge from the current research