Hunmo Kim

Actuator model of electrostrictive polymers (EPs) for microactuators

Recently, Electrostrictive polymers (EPs) are studied for micro-actuator, because of similarity of body tissue. Electrostrictive polymers (EPs) are based on the deformation of dielectric elastomer polymer in the presence of an electric field. Modeling of electrostrictive polymer has been studied, which is about voltage and displacement. And there are many parameters such as Youngs modulus, voltage, thickness of EPs, pre-strain, dielectric, frequency and temperature which effect to movement of EPs. To do exact modeling, all parameters are included. In order to use as actuator, we accurately understood about the parameter that we refer above. And we have to execute modeling which parameters are considered. We used FEM in order to understand effects of parameters. Specially, because of pre-strain effects are very important, we derive the relations of stress and strain by using elastic strain energy.

A Novel Passive Membrane Pumping Nano Fountain-Pen

In this paper, flow control of nano fountain pen using active membrane pumping is investigated. DPN (Dip Pen Nano- Lithography) has a shortcoming in which is the need of frequent loading and unloading while coating for broadband patterning. This issue is caused by a limit in quantity of ink, which is tied on the tip surface. The control of fluid injection using active membrane pumping in chambers is the answer of the problem. The flow rates in channels with the presence of capillary force are analyzed including the cantilever deflection and the control of mass flow rates by deflection of membrane. Finally, in this paper, the membrane deflection using a nano indentation equipment has been experimentally examined.

Development of electroactive silicate nanocomposites prepared for use as ionic polymer-metal composites (IPMCs) artificial muscles and sensors

Nanocomposites are a new class of composites which are typically nanoparticle-filled polymers. One promising kind of nanocomposite is clay-based and polymer-layered silicates nanocomposites because the starting clay materials are naturally abundant and, also, their intercalation chemistry is well understood at the present time. A certain clay, Montmorillonite (MxAl4- xMgx)Si8O20

Analysis of Line width with Nano Fountain Pen Using Active Membrane Pumping

(OH4 has two-dimensional layers of their crystal structure lattice where the layer thickness is around 1 nm with the lateral dimension of approximately 30 nm to a few microns. These layers organize themselves to form stacks, so-called the Gallery through a van der Walls gap in between them. In this work, Montmorillonite (MMT) was modified by a cationic surfactant so as to lower its surface energy significantly. Such a process gave rise to favorable intercalation of nanoparticles within the galleries. The obtained XRD patterns and TEM images indicate that the silicate layers are completely and uniformly dispersed (nearly exfoliated) in a continuous polymer matrix of Nafion that has been successfully used as a starting material of ionic polymer-metal composites (IPMCs).

Flow Control of Nano Fountain Pen Using Active Membrane Pumping

The intention of this research was investigated the line width that is written by NFP (nano fountain pen) using active membrane pumping in order to understand how to control it. The relationships between velocity of tip, concentration, and ink diffusion with line width were studied; it was found that variation of velocity of tip and concentration of ink affect directly to line width. Therefore, this study is shown a model of verifying line width through two conditions: velocity and diffusion.

A 3D IR Camera with Variable Structured Light for Home Service Robots

In this paper, flow control of nano fountain pen using active membrane pumping is investigated. This FPN has been integrated with pumping chambers, micro channels, and a high capacity reservoir for continuous ink feeding. The control of fluid injection using active membrane pumping in chambers is the answer of the problem. The flow rates in channels with the presence of capillary force are theoretically analyzed, including the cantilever deflection and the control of mass flow rates by deflection of membrane. Then, the above results are compared with numerical results based on the commercial code, FLUENT

Motion Planning for Non-Holonomic Mobile Manipulator Based Visual Servo under Large Platform Movement Errors at Low Velocity

There has shown a significant interest in a high performance of, at the same time, a compact size and low cost of, 3D sensor, in reflection of a growing need of 3D environmental sensing for service robotics. One of the important requirements associated with such a 3D sensor is that sensing does not irritate or disturb human in any way while working in close and continuous contact with human. Furthermore, such a 3D sensor should be reliable and robust to the change of environmental illumination as service robots are required to work day and night. This paper presents a 3D IR camera with variable structured light that is human friendly and robust enough for application to home service robots. Infrared is chosen as the sensing medium in order to meet the requirement of human friendliness and robustness to illumination change. A Digital Mirror Device (DMD) is employed to generate and project variable patterns at a high speed for real-time operation. In implementation, we emphasize the integration of modular components to support real-time sensing and compactness in size. A number of real-world experimentations are conducted, including a human face, a statue, and a plastic model. The experimental results have demonstrated that the implemented 3D IR Camera is robust to illumination change, in addition to its advantage of human friendliness.

Damped least square based genetic algorithm with Ggaussian distribution of damping factor for singularity-robust inverse kinematics

Abstract A non-holonomic mobile manipulator (NMM) is termed here as a robotic system in which a manipulator is mounted on a non-holonomic mobile platform. This paper presents a method for planning a motion of NMM for effectively performing eye-on-hand visual servo especially when there are excessive errors in platform movement at low velocity due to friction, slippage, backlash, or flexibility. Due to excessive errors in platform movement at low velocity, direct application of a conventional method for manipulator based visual servo to an NMM may not be effective for generating servo motions. In this paper, we propose a method of generating servo motions for an NMM based visual servo, which is not affected by the excessive platform movement errors at low velocity. We achieve this by generating a series of discrete optimal poses of NMM on-line as a higher level plan for servo motion. More specifically, NMM is to move successively to the chosen poses while maintaining a proper velocity for avoiding excessive movement errors and satisfying non-holonomic constraints until it reaches the final poses where the manipulator alone can servo to the target object while the platform can be kept stationary. We use the virtual visual servo by E. Marchand and F. Chaumette to make sure that the manipulator is able to reach a target object without violating its joint limits, its boundary of workspace and singularities. The on-line selection of local mobile platform poses is based on a local random search. Finally, simulations on a redundant NMM are carried out to demonstrate the effectiveness of the proposed method.