Sehoon Oh

Sehoon Oh
Daegu Gyeongbuk Institute of Science and Technology | DGIST · Department of Robotics Engineering

PhD

About

203
Publications
24,599
Reads
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3,170
Citations
Citations since 2017
87 Research Items
1995 Citations
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20172018201920202021202220230100200300
20172018201920202021202220230100200300
20172018201920202021202220230100200300
Additional affiliations
February 2015 - September 2020
Daegu Gyeongbuk Institute of Science and Technology
Position
  • Professor (Associate)
May 2013 - February 2015
Sogang University
Position
  • Research Professor
April 2012 - April 2013
Samsung Heavy Industries
Position
  • Engineer
Education
March 2003 - September 2005
The University of Tokyo
Field of study
  • Control Engineering

Publications

Publications (203)
Article
In this article, a novel robotic device is proposed that can realize a large range of compliance and a force sufficient to achieve human-balance training. The proposed device is called a virtual ground robot (VGR) and consists of a 3-degree-of-freedom parallel mechanism, which is driven by three series elastic actuators (SEAs). The proposed VGR can...
Article
Recently, autonomous driving technology has received significant interest, and consequently, various autonomous driving algorithms have been developed by researchers. An experimental (conventional) vehicle verifies the strategy for autonomous driving by testing the performance and feasibility of the corresponding algorithms. Implementation of the a...
Article
Triboelectric nanogenerators (TENG) is an effective approach for the development of self-powered systems, as it offers several flexibilities, such as wide material choice, high power density, simple fabrication process, etc. In this present work, the zeolite imidazole framework (ZIF-8) is synthesized by two approaches: solvent-assisted (SA) and sol...
Article
Steer-by-wire(SBW) system has been introduced to reduce the number of parts in a vehicle by eliminating the mechanical link between the steering wheel and the tire. Even though intensive research has been conducted on the SBW system, performance of the actuator system that provides the desired steering feel still needs improvement.Therefore, this p...
Conference Paper
Methods for designing a multitask controller for redundant robots are often implemented by a null space projector. Although null-space projection-based controllers can achieve the task decoupling performance among prioritized tasks, it is vulnerable to uncertainty due to modeling errors in practice. Accordingly, this paper provides an analytical pr...
Article
Full-text available
This study proposes an algorithm to save driving energy in an autonomous vehicle based on vehicle-to-vehicle technology. Saving the vehicular driving energy can be realized by reducing unnecessary deceleration and acceleration occurred in road congestion and by reducing the resistance caused by the internal factors of the vehicle. The algorithm pro...
Article
This brief presents a novel tracking control algorithm for a micro-robot based on dynamics and positional measurements. The algorithm improves the tracking performance and response time. We designed a two-degree-of-freedom (TDOF) control, which is widely utilized in industrial servo systems, for a micro-robot. Our TDOF control prevents undesirable...
Article
For robotic tasks that involve combined transmitting and contact force control, achieving high-performance motion control while ensuring stable environment contact is difficult. Among the factors that affect the quality of this force control, we may account vibrations due to misalignment in the mechanical components, actuator inaccuracies, non-line...
Article
Force sensor measurement noises and mechanical disturbances make realization of stable and robust force control systems challenging. With regard to this, a precise force control system that implements a combination of force and disturbance observers (DOBs) is proposed in this brief. The observers are a reduced-order multisensor-based force observer...
Article
Currently, the Electric Power Steering (EPS) system is an essential component of the vehicle because it provides assistive steering torque to the driver. To ensure a faster steering response, the position of the EPS in some vehicles is moved closer to the tire rather than the steering wheel. The steering torque, which is provided by the EPS in the...
Article
In this study, a novel mobile robot that can throw precisely a stone in a curling match is introduced. This mobile robot plays alongside a human team. Several requirements for developing the mobile robot are defined so that it follows the game rules and operates on an ice field. A static force analysis considering the operating conditions of the mo...
Article
Rendering a high impedance on a series elastic actuator (SEA) can improve motion control performance while retaining collision safety by a lower physical stiffness. The safe impedance range can be increased with high-gain velocity feedback control, but, in practice, this is limited by noise. This article applies the noise reduction disturbance obse...
Article
This paper proposes a new data-driven optimization of integrated control for flexible systems to achieve high-performance automatic control. The integrated control that is composed of feedback control, feedforward control and disturbance observer is adopted in this paper as the control framework that can effectively address the control problems of...
Article
This paper proposes a reduced-order multi-sensor-based force observer (RMFOB) for accurately estimating the force exerted on a load. The RMFOB excels in high frequency noise attenuation and low frequency time-varying measurement offsets compensation by using the combination of force sensor measurements, motor encoder measurements, and motor input s...
Article
Full-text available
The field of industrial electronics has evolved profoundly during recent decades, hand in hand with smart systems, enabling the development of new functionalities. It is now common for robots to perform many previously burdensome tasks and operate in collaboration with humans. Miniaturized sensors, which are capable of extracting industrial process...
Article
Series elastic actuators (SEAs) have had sound contributions in the robotics field, and significant breakthroughs have been achieved. Despite this fact, there are still drawbacks to their performance. The elastic spring, which provides compliance, limits the SEA's performance by lowering the bandwidth of force/torque generation, and this bandwidth...
Article
Robotic devices that can support a human's motions, such as exoskeletons, have recently drawn attention. Body weight support (BWS) systems are potential robotic devices that support and assist trunk motions with elaborate force control for rehabilitation and training exercises. This research presents a BWS system with two-dimensional motion assista...
Article
Full-text available
Nowadays, mobile robot platforms are utilized in various fields not only for transportation but also for other diverse services such as industrial, medical and, sports, etc. Mobile robots are also an emerging application as sports field robots, where they can help serve players or even play the games. In this paper, a novel caddie robot which can a...
Article
This paper offers a new insight to the achievable stiffness limitation of the impedance control of series elastic actuators (SEAs) by suggesting a comparative analysis of energy ports and passivity control framework at the energy port to enhance the maximum achievable rendered stiffness of SEAs. To this end, it is explored that SEAs has two differe...
Article
The cascade control of the servo system has an inner control loop and an outer control loop to achieve high-performance robust control. However, additional efforts are required because the inner and outer controllers need to be sequentially tuned. To address this problem, this paper proposes a novel iterative feedback tuning method for cascade cont...
Article
Rendering natural dynamics of robotic legs to have a spring-like behavior is a widely used method to realized the periodic hopping for the robot's locomotion. However, the impact force at the landing of the actual robot makes the realization of periodic hopping using the natural dynamics more challenging. In this paper, an optimal landing strategy...
Article
The inaccuracy of position and velocity controllers due to the vibration in the two-mass system in industrial robots cause devastating problems in both safety and productivity. To solve this problem, a method for tuning a cascade controller applied to two-mass systems based on Iterative Feedback Tuning (IFT) is proposed. The proposed new iterative...
Preprint
An important performance metric for series-elastic actuators is the range of impedance which they can safely render. Advanced torque control, using techniques such as the disturbance observer, improve torque tracking bandwidth and accuracy, but their impact on safe impedance range is not established. However, to define a safe impedance range requir...
Conference Paper
We developed the isokinetic exercise robot for single joint muscle training. The purpose of this study was to investigate the effects of contraction types (concentric vs. eccentric contractions) and contractile speeds (slow vs. fast contractions) controlled by the developed exercise robot on muscle strength and activations. Ten subjects voluntarily...
Article
Full-text available
The mass-spring system-like behavior is a powerful analysis tool to simplify human running/locomotion and is also known as the Spring Loaded Inverted Pendulum (SLIP) model. Beyond being just an analysis tool, the SLIP model is utilized as a template for implementing human-like locomotion by using the articulated robot. Since the dynamics of the art...
Article
Nowadays powered wheelchairs are widely utilized to help people’s locomotion. However, many commercialized powered wheelchairs still provide unsatisfactory ride quality, which is mainly due to not-well-designed control algorithm. To address this issue, this paper proposes a motion control algorithm that can improve the safety and riding comfort of...
Preprint
Full-text available
This paper develops an accurate force control algorithm for series elastic actuators (SEAs) based on a novel force estimation scheme, called transmission force observer (TFOB). The proposed method is designed to improve an inferior force measurement of the SEA caused by nonlinearities of the elastic transmission and measurement noise and error of i...
Preprint
The use of the Series Elastic Actuator (SEA) system as an actuator system equipped with a compliant element has contributed not only to advances in human interacting robots but also to a wide range of improvements in the robotics area. Nevertheless, there are still limitations in its performance; the elastic spring that is adopted to provide compli...
Article
This study involves proposing an assistive device using a wire-driven Series Elastic Actuator (SEA) for leg rehabilitation that can design and provide assistive force for exercises based on the physical ability of a patient. The proposed assistive device possesses a force estimation ability to measure the mass of the leg along with the force exerte...
Conference Paper
To measure muscle activity during motion is a significant topic in biomechanics. Even though EMG (electromyography) is utilized for this, musculoskeletal simulations are potential alternatives. In this paper, the accuracy of muscle activity calculation of two different algorithms are verified by comparing with EMG during three types of muscle contr...
Article
Full-text available
This paper presents an enhanced external torque estimation algorithm for series elastic actuators (SEAs) expanding the usability of the residual-based technique. Although the residual method demonstrates online torque estimation capability in diverse applications and thus becomes popular, it is practically challenging to achieve accurate estimation...
Article
Full-text available
Recently, Series Elastic Actuator (SEA) has emerged as a potential actuator system for various robotic applications where safe and precise interactive force control is required. Even though lots of research has been conducted on the mechanical/controller design and development of applications for SEAs, accurate force observation issue has not been...
Article
Full-text available
The Series Elastic Actuator (SEA) has recently been developed by many research groups and applied in various fields. As SEA is the combination of motor, spring, gear and load, various types and configurations of mechanism have been developed as SEAs to satisfy many requirements necessary for the applications. This paper provides a theoretical frame...
Article
As more robotic technology has been developed and implemented for rehabilitation training, the conventional rehabilitation methodology is expected to change and to have various functional modes other than Continuous Passive Movement (CPM). In this paper, the multifunctional training that are expected for the rehabilitation robot to provide is intro...
Conference Paper
Full-text available
Recently, the dynamic model of Series Elastic Actuator (SEA) has been researched intensively, and most of the approaches ignore the dynamics of the load part and model SEA as a simple mass damper spring system, which is valid only when SEAs contact with high impedance environments. To consider the dynamic model of SEA as a mass damper spring system...
Article
Full-text available
The robotic manipulators which are actively interacting with humans should be able to emulate the characteristics and performance of human body systems. Among various approaches to this end, this paper introduces a novel coordination system to control a two link manipulator in a more intuitive and human-friendly way: the polar coordinate system to...
Conference Paper
Full-text available
Nowadays, compliance is required in various research. Series Elastic Actuator (SEA) has been emerged as one of the promising actuator system, since it provides various benefits such as safety, force sensing, energy storing with its inherent compliance. While the SEA contributes not only to the human interacting robot but also to wide robotics area,...
Conference Paper
This paper introduces a state estimation method for the position control of a two-DoF planar manipulator in the polar coordinate system. The kinematics and dynamics of the two-DoF manipulator are analyzed utilizing the biarticular actuation mechanism and the polar coordinate system, which makes it possible to express the equation of motion in an ef...