Panagiotis Vartholomeos

Dynamics, Design and Simulation of a Novel Microrobotic Platform Employing Vibration Microactuators

This paper presents the analysis, design, and simulation of a novel microrobotic platform that is able to perform translational and rotational sliding with submicrometer positioning accuracy and develop velocities up to 1.5 mm/s. The platform actuation system is novel and based on centripetal forces generated by vibration micromotors. The motion principle is discussed in detail, and the dynamic model of the platform and of its actuation system is developed. Analytical expressions for the distinct modes of operation of the platform are derived and used to provide system design guidelines. Simulations are performed that verify the analytical results, demonstrate the platform capabilities, and examine its transient response. The microrobot design is simple, compact, and of low cost. In addition, the energy supply of the mechanism can be accomplished in an untethered mode using simple means, such as single-cell batteries. DOI: 10.1115/1.2168472

MRI-Guided Nanorobotic Systems for Therapeutic and Diagnostic Applications

This review presents the state of the art of magnetic resonance imaging (MRI)-guided nanorobotic systems that can perform diagnostic, curative, and reconstructive treatments in the human body at the cellular and subcellular levels in a controllable manner. The concept of an MRI-guided nanorobotic system is based on the use of an MRI scanner to induce the required external driving forces to propel magnetic nanocapsules to a specific target. It is an active targeting mechanism that provides simultaneous propulsion and imaging capabilities, which allow the implementation of real-time feedback control of the targeting process. The architecture of the system comprises four main modules: (a) the nanocapsules, (b) the MRI propulsion module, (c) the MRI tracking module (for image processing), and (d) the controller module. A key concept is the nanocapsule technology, which is based on carriers such as liposomes, polymer micelles, gold nanoparticles, quantum dots, metallic nanoshells, and carbon nanotubes. Descriptions of the significant challenges faced by the MRI-guided nanorobotic system are presented, and promising solutions proposed by the involved research community are discussed. Emphasis is placed on reviewing the limitations imposed by the scaling effects that dominate within the blood vessels and also on reviewing the control algorithms and computational tools that have been developed for real-time propulsion and tracking of the nanocapsules.

Analysis, design and control of a planar micro-robot driven by two centripetal-force actuators

This paper presents the motion analysis, design and position control of a novel, low cost, sliding micro-robot, which is actuated by centripetal forces generated by robot mounted vibration micro-motors. A new, two-micromotor design of the platform is presented, that improves system energy efficiency, and further does not necessitate for synchronous actuator operation and robot symmetry. The motion behavior of the micro-robot, for asynchronous actuation operation, is expressed analytically and simulation results are presented. A control strategy for microrobot x,thetasz, position control that employs two motor speed controllers, and a platform position controller is designed. The control system performance is evaluated through the simulation of a successful trajectory tracking task. A prototype of the micro-robot has been constructed and is presented

In Silico Studies of Magnetic Microparticle Aggregations in Fluid Environments for MRI-Guided Drug Delivery

A computational platform has been developed to perform simulation, visualization, and postprocessing analysis of the aggregation process of magnetic particles within a fluid environment such as small arteries and arterioles or fluid-filled cavities of the human body. The mathematical models needed to describe the physics of the system are presented in detail and also computational algorithms needed for efficient computation of these models are described. A number of simulation results demonstrate the simulation capabilities of the platform and preliminary experimental results validate simulation predictions. The platform can be used to design optimal strategies for magnetic steering and magnetic targeting of drug-loaded magnetic microparticles.

Simulation platform for self-assembly structures in MRI-guided nanorobotic drug delivery systems

Magnetic Resonance Imaging (MRI) guided nanorobotic systems that could perform diagnostic, curative and reconstructive treatments in the human body at the cellular and sub-cellular level in a controllable manner have recently been proposed. The concept of a MRI-guided nanorobotic system is based on the use of a MRI scanner to induce the required external driving forces to guide magnetic nanocapsules to a specific target. However, the maximum magnetic gradient specifications of existing clinical MRI systems are not capable of driving superparamagnetic nanocapsules against the blood flow and therefore these MRIs do not allow for navigation. The present paper proposes a way to overcome this critical drawback through the formation of micron size agglomerations where their size can be regulated by external magnetic stimuli. This approach is investigated through modeling of the physics that govern the self-assembly of the nanoparticles. Additionally a computational tool has been developed that incorporates the derived models and performs simulation, visualization and post-processing analysis. Preliminary simulation results demonstrate that external magnetic field causes aggregation of nanoparticles while they flow in the vessel. This is a promising result -in accordance with similar experimental results- and encourages further investigation on the nanoparticle based self-assembly structures for use in nanorobotic drug delivery.

Control of the multi agent micro-robotic platform MiCRoN

This paper presents the theoretical framework for the centralized control architecture of the multi agent micro-robotic platform MiCRoN. The entire control system architecture integrates sensory modules, modeling modules, and control modules. The latter are composed by (i) a high level simulation and autonomous execution unit that is capable for on-line multi-robot navigation with collision avoidance, (ii) a trajectory tracking unit for manipulation purposes, and (iii) a low level position controller that performs position control exploiting machine learning algorithms. The high level controllers take into account behaviors specific to the micro-scale. The performance of the layered control system is evaluated through simulations and preliminary hardware experiments on a micro-robotic platform. The application domain of the MiCRoN platform is cell manipulation, and 3-D assembly for micro-fabrication.

Analysis and Motion Control of a Centrifugal-Force Microrobotic Platform

This paper presents the analysis, design, and closed-loop motion control of a mobile microrobotic platform capable of micrometer positioning on a plane. The mobile microrobot, including chassis, actuators, drives, microprocessor, and electronics, is of low cost (less than

A haptic tele-manipulation environment for a vibration-driven micromechatronic device

20), can be fabricated rapidly and is made of commercially available components. Its motion is induced by centrifugal forces generated by two vibration motors installed inside the platform body. The asynchronous operation of the vibration motors is shown by simulation to result in planar motions of two degrees-of-freedom locally, with micrometer resolution. A motion controller has been designed to generate controlled motions using sets of motor angular velocities. A prototype has been developed and used to validate the motion principle and the controller efficacy. Open loop experiments show that the platform motion resolution is approximately 20 μm, while its speed is greater than 2 mm/s. Closed-loop experiments demonstrate a 5 μm resolution, i.e., a fourfold improvement compared to the open loop experiments. The low cost, the rapid fabrication, and the micrometer motion resolution suggest that this microrobotic platform is a promising solution for low-cost microfactories, where a group of such robots performs high throughput, advanced microassembly of microsystems.

Analysis and Design of a Novel Mini-platform Employing Vibration Micro-motors

In this paper, a novel haptic tele-manipulation environment is presented. This includes an interface between a master haptic mechanism and a slave mechatronic mechanism for biomedical operations. The novelty stems from the fact that the environments slave is a micromechatronic device driven by two inexpensive centripetal force vibration micromotors. The unique characteristics and challenges that arise during the haptic micromanipulation of the specific device are described and analyzed. The developed solutions are presented and discussed. The environment employs three input modes and two force control phases, which are described in detail. The haptic tele-manipulation environment is illustrated by several examples. These show that, while the interaction between the haptic mechanism and the vibration driven device is complicated, the micromanipulation of the device can be successful and appear to the operator as simple.

Analysis and Experiments on the Force Capabilities of Centripetal-Force-Actuated Microrobotic Platforms

This paper presents the analysis and design of a novel mini-robotic platform that is able to perform translational and rotational sliding with sub-micrometer positioning accuracy and develop velocities up to 1.5 mm/s. The platform actuation system employs vibration micro motors. The dynamic model of the platform and of its actuation system is presented, and analytical expressions are derived which provide design guidelines for the platform. Simulations are performed which verify the analytical results and demonstrate the platform capabilities. The platform design is simple, compact and of low cost. Also the energy supply of the mechanism can be accomplished in an untethered mode using simple means such as single cell batteries.