In this paper, an ecien t charge recovery method for driving piezoelectric actuators with low fre... more In this paper, an ecien t charge recovery method for driving piezoelectric actuators with low fre- quency square waves in low power applications such as mobile microrobots is investigated. Eciency issues related to periodic mechanical work of the actuators and the relationship among the driving elec- tronics eciency , the piezoelectric coupling factor, and the actuator energy transmission coecien t
A strategy for controlled pushing is presented for microassembly of 4.5μm polystyrene particles o... more A strategy for controlled pushing is presented for microassembly of 4.5μm polystyrene particles on a flat glass substrate using an atomic force microscope probe tip. Real-time vision based feedback from a CCD camera mounted to a high resolution optical microscope is used to track particle positions relative to the tip and target position. Tip-particle system is modeled in 2D as a nonholonomic differential drive robot. Effectiveness of the controller is demonstrated through experiments performed using a single goal position as well as linking a series of target positions to form a single complex trajectory. Cell decomposition and wavefront expansion algorithms are implemented to autonomously locate a navigable path to a specified target position. Control strategy alleviates problem of slipping and spinning during pushing.
For regenerative medicine applications, we need to expand our understanding of the mechanisms by ... more For regenerative medicine applications, we need to expand our understanding of the mechanisms by which nature assembles and functionalizes specialized complex tissues to form a complete organism. The first step towards this goal involves understanding the underlying complex mechanisms of highly organized behavior spanning not only diverse scientific fields, but also nano, micro and macro length-scales. For example, an engineered fibrous biomaterial scaffold possessing the hierarchal spatial properties of a native extracellular matrix (ECM) can serve as a building block upon which living cells are seeded for repair or regeneration. The hierarchical nature of ECM along with the inherent topological constraints of fiber diameter, fiber spacing, multi-layer configurations provide different pathways for living cells to adapt and conform to the surrounding environment. Our previously developed Spinneret based Tunable Engineered Parameters (STEP) technique to deposit biomaterial scaffolds ...
With the recent advancements in nano/microtechnology, it is now possible to fabricate fibrous sca... more With the recent advancements in nano/microtechnology, it is now possible to fabricate fibrous scaffolds at length scales which mimic living tissues.[1–3] Fabricating fibrous scaffolds is one promising component for tissue-engineering approaches and equally important is shaping them to spatially resemble living tissues. Numerous studies have indicated the importance of key engineered parameters: fiber diameter, fiber alignment, geometrical fiber spacing, scaffold mechanical strength, fiber roughness, and topological ...
While the atomic force microscope (AFM) was mainly developed to image the topography of a sample,... more While the atomic force microscope (AFM) was mainly developed to image the topography of a sample, it has been discovered as a powerful tool also for nanomanipulation applications within the last decade. A variety of different manipulation types exists, ranging from dip-pen and mechanical lithography to assembly of nanoobjects like carbon nanotubes (CNTs), deoxyribonucleic acid (DNA) strains, or nanospheres. The latter, the assembly of nanoobjects, is a very promising technique for prototyping nanoelectronical devices that ...
Three-dimensional (3D) heterogeneous assembly of coded microgels in enclosed aquatic environments... more Three-dimensional (3D) heterogeneous assembly of coded microgels in enclosed aquatic environments is demonstrated using a remotely actuated and controlled magnetic microgripper by a customized electromagnetic coil system. The microgripper uses different 'stick-slip' and 'rolling' locomotion in 2D and also levitation in 3D by magnetic gradient-based pulling force. This enables the microrobot to precisely manipulate each microgel by controlling its position and orientation in all x-y-z directions. Our microrobotic assembly method broke the barrier of limitation on the number of assembled microgel layers, because it enabled precise 3D levitation of the microgripper. We used the gripper to assemble microgels that had been coded with different colours and shapes onto prefabricated polymeric microposts. This eliminates the need for extra secondary cross-linking to fix the final construct. We demonstrated assembly of microgels on a single micropost up to ten layers. By incr...
Nanorobotics means literally the study of robots that are nanoscale in typical size, ie nanorobot... more Nanorobotics means literally the study of robots that are nanoscale in typical size, ie nanorobots, which have yet to be realized. Generally, nanorobots are large robots capable of manipulation nanoscale objects with nanometer resolution, eg a AFMbased nanorobotic manipulation system and a scanning electron microscope (SEM) equipped with a nanomanipulator. When studying nanorobotics, we first have to understand physics that underlies interactions at the nanoscale. At microscale, some basic micromanipulation ...
In this paper, a fine particle manipulation system using a piezoresistive microcantilever, which ... more In this paper, a fine particle manipulation system using a piezoresistive microcantilever, which is normally utilized in Atomic Force Microscopy, as the manipulator and force sensor, and a top-view Optical Microscope (OM) as the vision sensor is proposed. Modeling and control of the interaction forces among the manipulator, particle and surface have been realized for moving particles with sizes less
In this paper, a teleoperated n ano scale object manipulation system is proposed, and requirement... more In this paper, a teleoperated n ano scale object manipulation system is proposed, and requirements of such systems are defined. The system consists of a user interface utilizing visual and haptic displays (macro world), nano-manipulator, controller and sensors (nano world), and teleoperation control and rough to fine imaging and actuation tools (between macro and nano worlds). A home-made Atomic Force
In this paper, an ecien t charge recovery method for driving piezoelectric actuators with low fre... more In this paper, an ecien t charge recovery method for driving piezoelectric actuators with low fre- quency square waves in low power applications such as mobile microrobots is investigated. Eciency issues related to periodic mechanical work of the actuators and the relationship among the driving elec- tronics eciency , the piezoelectric coupling factor, and the actuator energy transmission coecien t
A strategy for controlled pushing is presented for microassembly of 4.5μm polystyrene particles o... more A strategy for controlled pushing is presented for microassembly of 4.5μm polystyrene particles on a flat glass substrate using an atomic force microscope probe tip. Real-time vision based feedback from a CCD camera mounted to a high resolution optical microscope is used to track particle positions relative to the tip and target position. Tip-particle system is modeled in 2D as a nonholonomic differential drive robot. Effectiveness of the controller is demonstrated through experiments performed using a single goal position as well as linking a series of target positions to form a single complex trajectory. Cell decomposition and wavefront expansion algorithms are implemented to autonomously locate a navigable path to a specified target position. Control strategy alleviates problem of slipping and spinning during pushing.
For regenerative medicine applications, we need to expand our understanding of the mechanisms by ... more For regenerative medicine applications, we need to expand our understanding of the mechanisms by which nature assembles and functionalizes specialized complex tissues to form a complete organism. The first step towards this goal involves understanding the underlying complex mechanisms of highly organized behavior spanning not only diverse scientific fields, but also nano, micro and macro length-scales. For example, an engineered fibrous biomaterial scaffold possessing the hierarchal spatial properties of a native extracellular matrix (ECM) can serve as a building block upon which living cells are seeded for repair or regeneration. The hierarchical nature of ECM along with the inherent topological constraints of fiber diameter, fiber spacing, multi-layer configurations provide different pathways for living cells to adapt and conform to the surrounding environment. Our previously developed Spinneret based Tunable Engineered Parameters (STEP) technique to deposit biomaterial scaffolds ...
With the recent advancements in nano/microtechnology, it is now possible to fabricate fibrous sca... more With the recent advancements in nano/microtechnology, it is now possible to fabricate fibrous scaffolds at length scales which mimic living tissues.[1–3] Fabricating fibrous scaffolds is one promising component for tissue-engineering approaches and equally important is shaping them to spatially resemble living tissues. Numerous studies have indicated the importance of key engineered parameters: fiber diameter, fiber alignment, geometrical fiber spacing, scaffold mechanical strength, fiber roughness, and topological ...
While the atomic force microscope (AFM) was mainly developed to image the topography of a sample,... more While the atomic force microscope (AFM) was mainly developed to image the topography of a sample, it has been discovered as a powerful tool also for nanomanipulation applications within the last decade. A variety of different manipulation types exists, ranging from dip-pen and mechanical lithography to assembly of nanoobjects like carbon nanotubes (CNTs), deoxyribonucleic acid (DNA) strains, or nanospheres. The latter, the assembly of nanoobjects, is a very promising technique for prototyping nanoelectronical devices that ...
Three-dimensional (3D) heterogeneous assembly of coded microgels in enclosed aquatic environments... more Three-dimensional (3D) heterogeneous assembly of coded microgels in enclosed aquatic environments is demonstrated using a remotely actuated and controlled magnetic microgripper by a customized electromagnetic coil system. The microgripper uses different 'stick-slip' and 'rolling' locomotion in 2D and also levitation in 3D by magnetic gradient-based pulling force. This enables the microrobot to precisely manipulate each microgel by controlling its position and orientation in all x-y-z directions. Our microrobotic assembly method broke the barrier of limitation on the number of assembled microgel layers, because it enabled precise 3D levitation of the microgripper. We used the gripper to assemble microgels that had been coded with different colours and shapes onto prefabricated polymeric microposts. This eliminates the need for extra secondary cross-linking to fix the final construct. We demonstrated assembly of microgels on a single micropost up to ten layers. By incr...
Nanorobotics means literally the study of robots that are nanoscale in typical size, ie nanorobot... more Nanorobotics means literally the study of robots that are nanoscale in typical size, ie nanorobots, which have yet to be realized. Generally, nanorobots are large robots capable of manipulation nanoscale objects with nanometer resolution, eg a AFMbased nanorobotic manipulation system and a scanning electron microscope (SEM) equipped with a nanomanipulator. When studying nanorobotics, we first have to understand physics that underlies interactions at the nanoscale. At microscale, some basic micromanipulation ...
In this paper, a fine particle manipulation system using a piezoresistive microcantilever, which ... more In this paper, a fine particle manipulation system using a piezoresistive microcantilever, which is normally utilized in Atomic Force Microscopy, as the manipulator and force sensor, and a top-view Optical Microscope (OM) as the vision sensor is proposed. Modeling and control of the interaction forces among the manipulator, particle and surface have been realized for moving particles with sizes less
In this paper, a teleoperated n ano scale object manipulation system is proposed, and requirement... more In this paper, a teleoperated n ano scale object manipulation system is proposed, and requirements of such systems are defined. The system consists of a user interface utilizing visual and haptic displays (macro world), nano-manipulator, controller and sensors (nano world), and teleoperation control and rough to fine imaging and actuation tools (between macro and nano worlds). A home-made Atomic Force
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