https://scholar.dgist.ac.kr/handle/20.500.11750/197 2026-04-04T11:07:59Z 2026-04-04T11:07:59Z 이현욱 오세훈 https://scholar.dgist.ac.kr/handle/20.500.11750/59330 2026-01-27T12:40:12Z 2025-10-31T15:00:00Z

Title: 상보 필터 기반 가속도 추정기법을 통한 탄성구동기의 강인한 임피던스 제어 Author(s): 이현욱; 오세훈 Abstract: This paper proposes a novel acceleration estimation method to improve the stability and performance of robust elastic structure preserving control for series elastic actuators. Elastic structure preserving (ESP) control has been proposed to overcome an inherent limitation in rendering high impedance while maintaining passivity. However, the effectiveness of ESP is highly dependent on accurate acceleration data, which is a challenge for existing estimation techniques. We introduce an acceleration estimation method that fuses position sensor data with a dynamics model. This hybrid approach overcomes the inherent limitations of existing techniques, such as the instability of low-pass filters and the inaccuracy of model-based estimations. Furthermore, we integrate a disturbance observer to grant robustness against modeling errors. These two components work in a complementary manner to suppress various error sources. Theoretical analyses and experimental results verify that the proposed method improves robustness and ensures stability. Consequently, the resulting controller achieves more accurate and reliable impedance rendering.

2025-10-31T15:00:00Z Chung, Young Hun Lee, Dohyeon Lee, Hyunwook Oh, Sehoon https://scholar.dgist.ac.kr/handle/20.500.11750/59329 2026-01-12T12:10:14Z 2025-10-31T15:00:00Z

Title: Enhanced 2-axis Gimbal Stabilization Control via a Hybrid Coordinate System Approach With Disturbance Observer Author(s): Chung, Young Hun; Lee, Dohyeon; Lee, Hyunwook; Oh, Sehoon Abstract: This paper proposes the line of sight (LOS) orientation cascade-type stabilization controller of a twoaxis gimbal with a novel integrated coordinate approach, the hybrid coordinate system (HCS), which combines joint and inertial coordinate frames. A robust controller is designed using this system, employing feed-forward (FF) stabilization and a disturbance observer (DOB) for each joint within the new coordinate system to eliminate external disturbances, internal joint friction, coupling torque, and model uncertainty. Controller parameters and controllable frame designs are determined through HCS model with multi-sensor configuration. Additionally, a filter is designed to address the drift issue that may occur in the given system. To verify the proposed control algorithm, a controller analysis and comparison with other controllers are conducted through actual external environment experiments. The HCS approach showed improved LOS stabilization performance compared with other methods.

2025-10-31T15:00:00Z Cheon, Dasol Nam, Kanghyun Oh, Sehoon https://scholar.dgist.ac.kr/handle/20.500.11750/59327 2026-01-12T12:10:14Z 2025-12-31T15:00:00Z

Title: Road Environment Aware Control Framework for Steering Feel Generation in Steer-by-Wire Systems Author(s): Cheon, Dasol; Nam, Kanghyun; Oh, Sehoon Abstract: In steer-by-wire (SBW) systems, where the steering wheel and the tire are not physically connected, the steering feel is artificially generated regardless of road conditions. Typically, SBW systems generate steering feel based on steering angle to steering torque models to provide specific reaction torques in response to the driver's steering input. However, since the steering wheel is not mechanically connected to the tire, the driver cannot feel the road surface condition. This article proposes a novel control algorithm framework that can extract and transfer road surface information while still following the desired steering feel model. The steering feel generation control and road wheel control are integrated to achieve this goal. Specifically, we propose a reference steering model (RSM) for steering feel generation and bilateral control (BiC) for integrated steering wheel and road wheel control. This allows us to reflect the road surface condition without changing the steering feel model or identifying the road surface parameters. We validate the effectiveness of our proposed control through experiments using an SBW test vehicle.

2025-12-31T15:00:00Z Lee, Deokjin Song, Junho Oh, Sehoon https://scholar.dgist.ac.kr/handle/20.500.11750/59326 2026-02-03T08:10:12Z 2025-12-31T15:00:00Z

Title: Data-driven Control Optimization on Frequency Response for Fast and Precise Motion of Flexible Joint Robots Author(s): Lee, Deokjin; Song, Junho; Oh, Sehoon Abstract: This paper presents a data-driven control optimization framework for flexible joint robots (FJR) based on frequency response function (FRF) data, enabling automated controller synthesis without explicit model identification. Unlike conventional model-based approaches that rely on accurate parameter estimation, the proposed method directly utilizes measured FRF data and formulates the controller design as a convex optimization problem. The controller maximizes control bandwidth while ensuring stability across a wide range of configurations. Experimental validation on a FJR demonstrates superior tracking accuracy, vibration suppression, and robustness compared to model-based methods. Furthermore, a high-speed drumming task demonstrates the ability of the controller to handle repeated impacts and inertia variations, highlighting the potential of FRF-based control for the fast and precise operation of flexible robotic systems. © 2016 IEEE.

2025-12-31T15:00:00Z