https://scholar.dgist.ac.kr/handle/20.500.11750/198 2026-04-05T11:06:15Z 2026-04-05T11:06:15Z Choi, Kiyoung Song, Junho Yun, Wonbum Oh, Sehoon https://scholar.dgist.ac.kr/handle/20.500.11750/60051 2026-02-10T12:10:20Z 2025-05-19T15:00:00Z

Title: Robust Orientation Control of Robot Manipulator Using Orientation Disturbance Observer Author(s): Choi, Kiyoung; Song, Junho; Yun, Wonbum; Oh, Sehoon Abstract: This paper presents a robust control algorithm for precise orientation control of robot manipulators using a disturbance observer (DOB) specifically designed for orientation dynamics. Our approach addresses the challenges of 3D orientation control by incorporating various orientation representations, such as Euler angles, quaternions, and exponential coordinates, and analyzing their impact on DOB performance. Through theoretical analysis and experimental validation, we demonstrate the effectiveness of our method in achieving high-precision orientation control under uncertainties and disturbances. This work offers a comprehensive framework for robust orientation control, advancing the application of DOB in complex robotic tasks.

2025-05-19T15:00:00Z Yeo, Changmin Görner, Martin Seo, Younghoon Hong, Jinsong Oh, Sehoon https://scholar.dgist.ac.kr/handle/20.500.11750/60048 2026-02-10T11:40:18Z 2025-10-16T15:00:00Z

Title: TEWD-DFO: A Soft-Soil-Aware Driving Force Observer Using Terramechanics-Enhanced Wheel Dynamics for Planetary Rover Author(s): Yeo, Changmin; Görner, Martin; Seo, Younghoon; Hong, Jinsong; Oh, Sehoon Abstract: Accurate driving force estimation is critical for ground vehicles operating in soft-soil terrains, where complex wheel-soil interactions involving sinkage and shear effects significantly affect vehicle mobility. Conventional Driving Force Observers (DFOs), initially developed for rigid road conditions, fail to account for these terrain-specific nonlinearities, leading to estimation offset and substantial errors. To overcome this limitation, this paper proposes a Terramechanics-Enhanced Wheel Dynamics (TEWD) model that explicitly integrates soil resistance derived from established wheel-soil interaction models. Based on the TEWD model, we develop a new driving force observer, termed TEWD-DFO, that estimates driving forces solely from internal vehicle signals without requiring additional external force sensors. The proposed method is validated through simulations conducted in the ProjectChrono environment under soft-soil conditions. Simulation results demonstrate that the TEWD-DFO significantly reduces estimation offsets and achieves robust driving force estimation performance, indicating its potential applicability in enhancing vehicle stability and control accuracy in realistic soft-soil scenarios. © 2025 IEEE.

2025-10-16T15:00:00Z Hwang, Jihoon Seo, Younghoon Oh, Sehoon Nam, Kanghyun https://scholar.dgist.ac.kr/handle/20.500.11750/59152 2026-02-10T12:10:21Z 2025-06-19T15:00:00Z

Title: Intuitive Human-Machine Steering Interface for 4WIS and Synchronous Steering Interaction Control Considering Steering Intention Author(s): Hwang, Jihoon; Seo, Younghoon; Oh, Sehoon; Nam, Kanghyun Abstract: Recent advancements in electric chassis technologies such as steer-by-wire (SBW), in-wheel motors, and e-corner modules have highlighted the potential of four-wheel independent steering (4WIS) vehicles. Although these vehicles offer expanded motion capabilities, conventional interfaces with one steering DOF are insufficient to implement expanded motions. To address this, this paper proposes an intuitive human-machine steering interface (HMSI) capable of effectively capturing driver steering intention with synchronous steering interaction control. The proposed HMSI supplements the conventional steering wheel with additional DOFs, enabling intuitive and continuous control of various vehicle motions. The developed control method distinguishes intentional steering inputs from unintended disturbances, providing clean steering commands suitable for safe vehicle control. Driver torque inputs are estimated using a sensorless disturbance observer-based approach, while an admittance control-based interaction model dynamically provides steering force feedback. Experiments validate that unintended motions are effectively damped, and intentional steering inputs are extracted, ensuring stable vehicle handling. Additionally, the proposed system demonstrates the capability to vary steering feel, paving the way for future research on adaptive steering feel generation and motion-command methodologies in 4WIS vehicles. © 2025 Elsevier B.V., All rights reserved.

2025-06-19T15:00:00Z Lee, Chan Bae, Sangjin Kang, Woosong Oh, Sehoon https://scholar.dgist.ac.kr/handle/20.500.11750/58979 2025-08-29T08:40:11Z 2020-09-13T15:00:00Z

Title: Transparent Torque Sensor-less Impedance Rendering for Low-cost Direct Drive Motor Author(s): Lee, Chan; Bae, Sangjin; Kang, Woosong; Oh, Sehoon Abstract: Low-cost outer runner Direct Drive (DD) motor has been spotlighted in recent robotic applications. However, torque ripple caused by the low production quality of the motor lowers not only the torque control performance but also impedance rendering performance. This paper proposes transparent sensor-less impedance control to improve impedance rendering performance for the low-cost DD motor. The novel criteria impedance rendering transparency is derived to define the problem of sensor-less impedance control by using low-cost DD motor. Torque ripple, the main problem, is measured and analyzed to develop the high-performance impedance controller. The phase synchronization method is also added to release the implementation issue. Experimental verification has conducted the performance of the proposed method.

2020-09-13T15:00:00Z