マルチ スケール キノウ ヲ ユウスル コウソク ジドウ マイクロ マニピュレーション システム

Ebubekir Avci, Chanh-Nghiem Nguyen, Kenichi Ohara, Yasushi Mae, Tatsuo Arai, Analysis and suppression of residual vibration in microhand for high-speed single-cell manipulation, International Journal of Mechatronics and Automation, 2013-Vol.3, No.2, pp.110-11

Microgripper force feedback integration using piezoresistive cantilever structure

Force feedback is an important feature in most microgripper applications, but it is commonly overlooked. To successfully implement this feature, a cantilever structure has been designed and fabricated to integrate force feedback into a microhand gripper. The piezoresistive properties of doped polysilicon are used to transduce the mechanical stress of an object pressing against the cantilever sensor, resulting in a change in resistance or voltage capable of being monitored with external hardware. The force sensing structure was designed to have a fabrication process compatible with that of the microhand, allowing for their eventual integration. This fabrication process uses both bulk and surface micromachining techniques to create the cantilever structure, a balloon actuator (utilized in the microhand), and the interconnect to interact with both the electrical sensors and the pneumatic actuators. The prototype fabrication successfully defined the majority of the MEMS device with the exception of the final step. The release of the cantilever failed due to underetching of the entire device rather than just the cantilever, which was desired. Recommendations to solve this problem and improve the fabrication process are presented

Development of novel micropneumatic grippers for biomanipulation

Microbjects with dimensions from 1 μm to 1 mm have been developed recently for different aspects and purposes. Consequently, the development of handling and manipulation tools to fulfil this need is urgently required. Micromanipulation techniques could be generally categorized according to their actuation method such as electrostatic, thermal, shape memory alloy, piezoelectric, magnetic, and fluidic actuation. Each of which has its advantage and disadvantage. The fluidic actuation has been overlooked in MEMS despite its satisfactory output in the micro-scale. This thesis presents different families of pneumatically driven, low cost, compatible with biological environment, scalable, and controllable microgrippers. The first family demonstrated a polymeric microgripper that was laser cut and actuated pneumatically. It was tested to manipulate microparticles down to 200 microns. To overcome the assembly challenges that arise in this family, the second family was proposed. The second family was a micro-cantilever based microgripper, where the device was assembled layer by layer to form a 3D structure. The microcantilevers were fabricated using photo-etching technique, and demonstrated the applicability to manipulate micro-particles down to 200 microns using automated pick-and-place procedure. In addition, this family was used as a tactile-detector as well. Due to the angular gripping scheme followed by the above mentioned families, gripping smaller objects becomes a challenging task. A third family following a parallel gripping scheme was proposed allowing the gripping of smaller objects to be visible. It comprises a compliant structure microgripper actuated pneumatically and fabricated using picosecond laser technology, and demonstrated the capability of gripping microobject as small as 100 μm microbeads. An FEA modelling was employed to validate the experimental and analytical results, and excellent matching was achieved

Advanced medical micro-robotics for early diagnosis and therapeutic interventions

Recent technological advances in micro-robotics have demonstrated their immense potential for biomedical applications. Emerging micro-robots have versatile sensing systems, flexible locomotion and dexterous manipulation capabilities that can significantly contribute to the healthcare system. Despite the appreciated and tangible benefits of medical micro-robotics, many challenges still remain. Here, we review the major challenges, current trends and significant achievements for developing versatile and intelligent micro-robotics with a focus on applications in early diagnosis and therapeutic interventions. We also consider some recent emerging micro-robotic technologies that employ synthetic biology to support a new generation of living micro-robots. We expect to inspire future development of micro-robots toward clinical translation by identifying the roadblocks that need to be overcome

Hybrid optical and magnetic manipulation of microrobots

Microrobotic systems have the potential to provide precise manipulation on cellular level for diagnostics, drug delivery and surgical interventions. These systems vary from tethered to untethered microrobots with sizes below a micrometer to a few microns. However, their main disadvantage is that they do not have the same capabilities in terms of degrees-of-freedom, sensing and control as macroscale robotic systems. In particular, their lack of on-board sensing for pose or force feedback, their control methods and interface for automated or manual user control are limited as well as their geometry has few degrees-of-freedom making three-dimensional manipulation more challenging. This PhD project is on the development of a micromanipulation framework that can be used for single cell analysis using the Optical Tweezers as well as a combination of optical trapping and magnetic actuation for recon gurable microassembly. The focus is on untethered microrobots with sizes up to a few tens of microns that can be used in enclosed environments for ex vivo and in vitro medical applications. The work presented investigates the following aspects of microrobots for single cell analysis: i) The microfabrication procedure and design considerations that are taken into account in order to fabricate components for three-dimensional micromanipulation and microassembly, ii) vision-based methods to provide 6-degree-offreedom position and orientation feedback which is essential for closed-loop control, iii) manual and shared control manipulation methodologies that take into account the user input for multiple microrobot or three-dimensional microstructure manipulation and iv) a methodology for recon gurable microassembly combining the Optical Tweezers with magnetic actuation into a hybrid method of actuation for microassembly.Open Acces

Scalability study for robotic hand platform

The goal of this thesis project was to determine the lower limit of scale for the RIT robotic grasping hand. This was accomplished using a combination of computer simulation and experimental studies. A force analysis was conducted to determine the size of air muscles required to achieve appropriate contact forces at a smaller scale. Input variables, such as the actuation force and tendon return force, were determined experimentally. A dynamic computer model of the hand system was then created using Recurdyn. This was used to predict the contact (grasping) force of the fingers at full-scale, half-scale, and quarter-scale. Correlation between the computer model and physical testing was achieved for both a life-size and half-scale finger assembly. To further demonstrate the scalability of the hand design, both half and quarter-scale robotic hand rapid prototype assemblies were built using 3D printing techniques. This thesis work identified the point where further miniaturization would require a change in the manufacturing process to micro-fabrication. Several techniques were compared as potential methods for making a production intent quarter-scale robotic hand. Investment casting, Swiss machining, and Selective Laser Sintering were the manufacturing techniques considered. A quarter-scale robotic hand tested the limits of each technology. Below this scale, micro-machining would be required. The break point for the current actuation method, air muscles, was also explored. Below the quarter-scale, an alternative actuation method would also be required. Electroactive Polymers were discussed as an option for the micro-scale. In summary, a dynamic model of the RIT robotic grasping hand was created and validated as scalable at full and half-scales. The model was then used to predict finger contact forces at the quarter-scale. The quarter-scale was identified as the break point in terms of the current RIT robotic grasping hand based on both manufacturing and actuation. A novel, prototype quarter-scale robotic hand assembly was successfully built by an additive manufacturing process, a high resolution 3D printer. However, further miniaturization would require alternate manufacturing techniques and actuation mechanisms

Lateral bending liquid crystal elastomer beams for microactuators and microgrippers

With the rapid development of microsystems in the last few decades, there is a requirement for high precision tools for micromanipulation and transportation of micro-objects, such as microgrippers, for applications in microassembly, microrobotics, life sciences and biomedicine. Polymer based microgrippers and microrobots executing various tasks have been of significant interest as an alternative to the traditional silicon and metal based counterparts due to the advantages of low cost fabrication, low actuation temperature, biocompatibility, and sensitivity to various stimuli. The exceptional actuation properties of liquid crystal elastomers (LCE) have made these materials highly attractive for various emerging applications in the last two decades. Large programmable deformations and the benefits offered by the elastic, thermal and optical properties of LCEs are suitable for implementing stimuli-responsive microgrippers as well as various biomimetic motion in soft robots. In this thesis, a method and the associated processes for fabrication and molecular alignment in LCE were developed, which enabled new functionality and improved performance of the LCE based microactuators and microgrippers, providing controlled response by thermal and remote photothermal actuation, and allowing easy integration of the LCE end-effectors into robotic systems for automated operation. Lateral bending actuation has been demonstrated in LCE microbeams of 900 µm of length and 40 µm of thickness, owing to the new monolithic micromolding technique using vertical patterned walls for alignment. The effects of parameters such as the beam width, the size of the microgrooves, and the surface treatment method on the behavior of the microactuators were studied; the internal alignment pattern of liquid crystals in the structure was investigated by different microscopy methods. An efficient method for finite element modeling of the bending LCE actuators was developed and experimentally verified, based on the gradient of equivalent thermal expansion in the multi-layer structure, which was able to predict the bending behavior of the actuators in a large range of thicknesses as well as rolling behavior of the actuators of tapered thickness. The novel LCE microgripper with in-plane operation showed efficient thermal and photothermal actuation, achieving the gripping stroke of 64 µm under the light intensity of 239 mW/cm2 for the gripper length of 900 µm, which is more efficient than the typical SU-8 polymer based microgrippers of the same dimensions. The LCE gripper was successfully demonstrated for the application in manipulation of the objects of tens to hundreds of micrometers in size. Therefore, the novel LCE microgripper bridges the gap in the LCE-based gripper technologies for typical object size in applications for systems microassembly, biological and cell micromanipulation. The lateral bending functionality enabled by the proposed method expands design opportunities for thermal and photothermal LCE microactuators, providing an effective route toward realization of new modes of gripping, locomotion, and cargo transportation in soft microrobotics and micromanipulation

Optical sorting and manipulation of microscopic particles

Over the last few decades, the use of light to control and manipulate microscopic particles has become widespread. These methods are enabling new areas of research to flourish across the physical and biological sciences. This thesis describes investigations into both optical trapping and the closely related field of optical sorting. It documents the development of a variety of new techniques. The thesis begins with a short review of optical trapping and existing methods for sorting mixtures of microscopic particles. The first half of this chapter highlights some of the reasons behind optical trapping's rapid growth in popularity. By reviewing an array of methods for sorting particles and discussing the relative merits of each, the case for optical sorting is established. The second chapter describes research into using a spatial light modulator to create three-dimensional optically trapped colloidal structures using the time-sharing technique. Limiting factors inherent in the technology are discussed in detail. The third chapter reviews a sophisticated particle-tracking software package that has proved to be a considerable success. It was developed explicitly with colloidal microscopy in mind and experimental plots produced by the software are used throughout the thesis. Experimental studies have been performed into the behaviour of microscopic particles moving under the influence of two classes of propagation-invariant beams: Mathieu beams and Bessel beams. The Bessel beam studies have been complimented by a theoretical model and have led ultimately to a new method for the static optical sorting of both solid particles and biological cells, with particular emphasis on human blood. The fifth and final chapter describes how re-configurable optical devices can be implemented to spatially separate different colloidal species. A new method for creating arbitrary optical landscapes using an acousto-optic modulator is reported. This new technique is then used to optically sort four particle species simultaneously - the first experimental demonstration of polydisperse optical fractionation. Additionally, experiments are reported that demonstrate controlled, static optical sorting using a spatial light modulator