Hyoyuk Choi

This paper presents a novel design of dielectric elastomer actuator (DEA), called single body dielectricelastomer actuator (SDEA), to improve the performance of existing DEAs. The DEA is typically configuredwith stacking multiple dielectric elastomer film and linearly contracted according to the applied voltage. SDEA isfabricated monolithically without external frame and has the advantages of flexibility and light weight. Thus, it isapplicable to various configurations of actuators such as twist

This paper presents an in-pipe robot, called MRINSPECT V (Multifunctional Robotic crawler for In-pipe inSPECTion V), which is under development for the inspection of pipelines with a nominal 8-inch inside diameter. To travel freely in every pipeline element, the robot adopts a differential driving mechanism that we have developed. Furthermore, by introducing clutches in transmitting driving power to the wheels, MRINSPECT V is able to select the suitable driving method according to the shape of t

Face robots capable of expressing their emotional status, can be adopted as an efficient tool for friendly communication between the human and the machine. In this paper, we present a face robot actuated with artificial muscle based on dielectric elastomer. By exploiting the properties of dielectric elastomer, it is possible to actuate the covering skin, eyes as well as provide human-like expressivity without employing complicated mechanisms. The robot is driven by seven actuator modules such ey

This paper presents the development and experimental evaluation of a collision detection method for robotic manipulators sharing aworkspace with humans. Fast and robust collision detection is important for guaranteeing safety and preventing false alarms. The maincause of a false alarm is modeling error. We use the characteristic of the maximum frequency boundary of the manipulator's dynamicmodel. The tendency of the frequency boundary’s location in the frequency domain is applied to the collisio

This study presents a highly stretchable dielectric elastomer material for transducers based on acrylonitrilebutadiene rubber (NBR). The material has advantages in that its mechanical and electrical properties can bemodified according to the requirements of applications by changing the content of additives such as carbon black(CB), multi-walled carbon nanotubes (MWCNT), and graphite (GP) in the NBR matrix. First, the changes of dielectricpermittivity depending on the additives are discussed. Mor

In this paper, we present an artificial muscle actuator producing rectilinear motion, called the Tube–Spring–Actuator (TSA). The TSA is supposed to be a prospective substitute in areas requiring macro forces such as robotics. It is simply configured from a synthetic elastomer tube with an inserted spring. The design of the TSA is described in detail and its analysis is conducted to investigate the characteristics of the actuator based on the derived model. In addition, the performance of the pro

This paper presents a map building method for an in-pipe robot to navigate inside urban gas pipelines autonomously, whose configuration is unknown or partially known. In the first, we explain the reason why the navigation in the pipeline is difficult and then, present a method for obtaining a robot’s posture by using a pipeline’s unique geometrical features. The robot can obtain its heading direction by detecting the standardized geometries of pipe elements. Based on the method, we propose a rob

The actuation of electrostrictive polymer (EP) actuator under electric field is known due to the electrostatic force between the parallel compliant electrodes on both sides of polymer film, which means the magnitude of electric potential between the electrodes is one of the determinative parameters of the actuation. The actuation is also dependent on the material properties such as dielectric constant and elastic modulus of polymers. In order to maximize the actuation behavior, high dielectric c

This paper proposes a method of exploring the local shape of an unknown object using the force and torque information obtained from active touch. In the first, we present a method to estimate an unknown curvature, using rolling and sliding motion with a force/torque sensor attached to the fin-gertip of the hand. Then, the normal curvature equation from 2D curvatures is obtained. Finally we present a reconstruction algorithm of local geometry by using a normal curvature equation, which is compose

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 (M<SUB>x</SUB>Al<SUB>4- x</SUB>Mg<SUB>x</SUB>)Si<SUB>8</SUB>O<SUB>20$(OH</SUB><SUB>4</SUB> has two-dimensional layers of their crystal str

Edge detection plays an important role in object recognition and exploration. In this paper, we propose an efficient tracking algorithm, which uses a coarse resolution tactile sensor set, for edge detection of a 2D shape object. Although many researchers have often used a tactile sensor with high resolution such as a 10x10 or higher for edge detection, in this research, we use a 2x2 tactile sensor to track the edges of an object. Using this type of low resolution sensor, we can reduce the manufa

This paper presents a simple method to control the motion of a quadruped robot in unknown rough terrain using a full dynamic model. First, using the stiffness control method, the behavior of the four legs is approximated using four 3D spring damper systems. In this way, the dynamic model can be derived in Cartesian space. Based on this model, a control strategy is proposed to preserve the asymp-totical stability of the system. In addition, a reflex motion control is introduced to cope with the r

This paper introduces a robot called the MRINSPECT V (Multifunctional Robotic crawler for Inpipe inSPECTion V) for the inspection of pipelines with a nominal 8-in inside diameter. Based on the mechanism of the previous model MRINSPECT IV, we developed a new MRINSPECT V by using the differential driving mechanism, so that just simply controlling the speed of each driving units helps the robot to travel effectively inside the pipelines. Furthermore, the robot uses clutches in transmitting driving

In this paper, we present a control method for a quadruped walking robot inspired from the locomotion of quadrupeds. A simple and useful framework for controlling a quadruped walking robot is presented, which is obtained by observing the stimulus-reaction mechanism, the gravity load receptor and the manner of generating repetitive motions from quadrupeds. In addition, we propose a new rhythmic pattern generator that can relieve the large computational burden on solving the kinematics. The propos