https://scholar.dgist.ac.kr/handle/20.500.11750/197 Mon, 10 Aug 2026 11:54:45 GMT 2026-08-10T11:54:45Z https://scholar.dgist.ac.kr/handle/20.500.11750/60588 Title: Data-Driven Robust Subspace Predictive Control With Embedded Disturbance Observer Structure Author(s): Kong, Taejune; Dinkla, Rogier; Van Wingerden, Jan-Willem; Oomen, Tom; Oh, Sehoon Abstract: Subspace predictive control (SPC) is a data-driven control strategy that utilizes input-output measurements to predict future system behavior without requiring explicit model identification. Conventional SPC exhibits vulnerability to an unknown input disturbance, leading to degraded control performance and steady-state errors. To address these limitations, this article proposes a robust SPC method that inherently mitigates the effect of a constant input disturbance by augmenting the state-space representation through the internal model principle (IMP). This augmentation enables the controller to achieve integral action without requiring a separate disturbance observer (DOB) design. The proposed method is implemented in a data-driven framework, where an auxiliary disturbance is introduced into the data-driven algorithm to enhance disturbance rejection. A transfer function analysis verifies that the proposed Robust SPC eliminates a constant disturbance while maintaining the role of a DOB. Experimental validation on a two-inertia system confirms that the proposed method significantly improves reference tracking performance compared to conventional SPC, demonstrating its effectiveness in disturbance rejection without additional modeling complexity. Tue, 30 Jun 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60588 2026-06-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/60585 Title: Robust Position Control of Series Elastic Actuator via Load Port Control and Novel Acceleration Estimation Author(s): Lee, Hyunwook; Cheon, Dasol; Oh, Sehoon Abstract: Precise position control of Series Elastic Actuator (SEA) is crucial yet challenging. Conventional methods like Load Feedback Control (LFC) compromise stability due to inherent phase lag, while Motor Feedback Control (MFC) can ensure stability but may introduce load-side vibrations during transients. This paper presents Load Port Control (LPC) as an alternative approach to achieve both stability and high-performance position tracking for SEA. Implementing LPC requires accurate load acceleration estimation, which is complicated by the limitations of existing methods; differentiation with low-pass filtering introduces phase delay, and simplified dynamics models are sensitive to external torques. To overcome this, we propose a novel acceleration estimation method that fuses low-pass filtered position information with high-pass filtered dynamics model data. This approach mitigates phase lag while enhancing robustness against external torque. The effectiveness of the LPC strategy is evaluated through theoretical analysis and experiments on a two-mass testbed. Under the evaluated conditions, the proposed method showed improved stability, tracking performance, and disturbance robustness relative to the compared methods. Fri, 31 Jul 2026 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/60585 2026-07-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59330 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. Fri, 31 Oct 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/59330 2025-10-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59329 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. Fri, 31 Oct 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/59329 2025-10-31T15:00:00Z