Jae-Wook Jeon

Biomimetic soft actuator: design, modeling, control, and applications

A new biomimetic linear actuator named Antagonistically Driven Linear Actuator (ANTLA) that could be directly employed in both macro and microscale of robotic applications is introduced in the present work. The presented actuator provides cost effectiveness and simple fabrication process thanks to its plain construction. In addition to producing basic bidirectional rectilinear motions, the actuator is able to modulate its compliance that might be one of the critical elements of the actuator functionality for the biomimetic applications. For the test, the proposed actuator concept is fabricated and assembled in a microscale robot that generates annelid motion.

Braille display device using soft actuator

Tactile sensation is one of the most important sensory functions along with the auditory sensation for the visually impaired because it replaces the visual sensation of the persons with sight. In this paper, we present a tactile display device as a dynamic Braille display that is the unique tool for exchanging information among them. The proposed tactile cell of the Braille display is based on the dielectric elastomer and it has advantageous features over the existing ones with respect to intrinsic softness, ease of fabrication, cost effectiveness and miniaturization. We introduce a new idea for actuation and describe the actuating mechanism of the Braille pin in details capable of realizing the enhanced spatial density of the tactile cells. Finally, results of psychophysical experiments are given and its effectiveness is confirmed.

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.

Biomimetic actuator based on dielectric polymer

A new biomemetic actuator is proposed. The actuator realizes bidirectional actuation since it is with a stretched film antagonistically configured with compliant electrodes. Also, it is distinguished from existing actuators with respect to the controllability of its compliance. Bidirectional actuation and compliance controllability are important characteristics for the artificial muscle actuator and the proposed one accomplishes these requirements without any mechanical substitute or complicated algorithms. In this paper its basic concepts and working principles are introduced with static and dynamic analysis. Control strategies for displacement as well as stiffness are introduced, and experimental results are given to confirm the effectiveness of the proposed methods. In addition, an example of robotic actuating devices is given to confirm the usefulness of the proposed actuator.

Stable powered device (PD) management using RS422 technique in power sourcing equipment (PSE)

In this study we monitor powered divices by making additional connections using the RS422 communication method between power-sourcing equipment and powered devices using power over Ethernet according to IEEE802.3af in the current Alternative A composition. The aim is to create an efficient and stable powered device environment. That is, an RS485 communication line is connected to pins 4 and 5 or 7 and 8 at Alternative A of a power-sourcing equipment system, thereby leading to communication between the power-sourcing equipment and the powered device. Accordingly, the power-sourcing equipment can monitor the powered device. Power-sourcing equipment is available for monitoring powered devices in real time, and can stably operate powered devices. These can become unstable due to abnormal events. Furthermore, the potential communication between power-sourcing equipment and powered deivces creates the framework for forming an intelligent Power over Ethernet system. PDs that require high stability are being launched. This study presents a method to improve their stability.

A fault-tolerant gateway for in-vehicle networks

This paper presents a fault-tolerant gateway embedded system that uses two micro-controllers. One microcontroller performs the main function of achieving a gateway, often called by the main micro-controller. In contrast, another plays the role of checker for the main micro-controller, and is called the sub micro-controller. To achieve fault-tolerance, the checker monitors the state of the main micro-controller. In this paper, we propose hardware architecture for fault-tolerance and evaluate the performance of the proposed system.

Electrostrictive polymer actuators and their control systems

Electrostrictive polymers such as silicone, acrylic, and polyurethane can achieve large strain and stress with high electric field. This property can make electrostrictive polymers useful actuators. While there are some limitations in reducing existing actuators, there are few in electrostrictive polymer actuators. Therefore, an electrostrictive polymer can be used to design an actuator of a micro robot system. In this paper, an actuator system, which consists of an electrostrictive polymer actuator and its controller, is designed and is implemented. Major characteristics about this actuator system are measured and are discussed. Also the performance of this actuator system under a control technique is measured.

Implementation and analysis of the embedded master for EtherCAT

The Ethernet-based network protocol is widely using in industrial environments. Its advantages include high speed, high performance, operation over long distances, and better interoperability. A number of techniques are used to implement the Ethernet protocol for the needs of industrial processes that must provide real time processes. This paper analyses network performance of an Embedded system based master using EtherCAT. The network performance characteristics of the Embedded systems are compared by considering into the factors affecting their performance in a network system. This may determine reasons why network performance differs between factors.

Design and Implementation of a FAT File System for Reduced Cluster Switching Overhead

In this paper, we present design and implementation of a New FAT file system (NFAT) for mobile multimedia devices. Conventional file system which has been used for personal computers is the FAT and it is still adopted for most of current portable devices. The major problem of the FAT is overhead due to cluster switching which involves retrieving and updating of cluster connection information saved on the file allocation table. Because of this overhead, response time of file read and write operation cannot be guaranteed in the FAT. This paper proposes the NFAT which guarantees expected response time by reducing cluster switching overhead when it reads and writes data for portable multimedia devices. To verify our proposal, we have implemented a prototype NFAT file system on ARM9 development board and a Secure Digital Card. The experimental results show that the NFAT does not have irregular response time when performing read/write operations. Therefore, the NFAT is suitable file system for mobile devices which have real-time requirements in reading and writing multimedia data.

Analysis of implementing OSEK NM with two types of ECU network

ldquoOpen Systems and their interfaces to electronics in Motor Vehiclesrdquo (OSEK) is a real-time operating system used in vehicle systems. OSEK is a standard operating system used by many carmakers. OSEK has a network management algorithm, OSEK network management (OSEK NM). It has two management rules: Direct NM and Indirect NM. Direct NM and Indirect NM are implemented in two network protocols for ECUs, CAN and LIN. Their advantages and disadvantages are analyzed. When two OSEK NM management rules are applied to the communication protocols, application problems and differences could be found. Performance analysis in real applications and network management rules for each network protocol are proposed.