• Journal of Auto-vehicle Safety Association
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• v.12 no.3
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• pp.13-19
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• 2020

This paper presents steering controller for unintended lane departure avoidance under crosswind using vehicle lateral disturbance estimation. Vehicles exposed to crosswind are more likely to deviate from lane, which can lead to accidents. To prevent this, a lateral disturbance estimator and steering controller for compensating disturbance have been proposed. The disturbance affecting lateral motion of the vehicle is estimated using Kalman filter, which is on the basis of the 2-DOF bicycle model and Electric Power Steering (EPS) module. A sliding mode controller is designed to avoid unintended the lane departure using the estimated disturbance. The controller is based on the 2-DOF bicycle model and the vision-based error dynamic model. A torque controller is used to provide appropriate assist torque to driver. The performance of proposed estimator and controller is evaluated via computer simulation using Matlab/Simulink.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.7
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• pp.702-708
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• 2010

Reaction wheel assemblies(RWA) are expected to be one of the largest high frequency disturbance sources to the optical payload of satellites. To ensure the tight pointing-stability budget and high image quality of satellites, a vibration isolation device should be applied to the main disturbances. For developing the isolating system, the disturbances need to be identified and modeled accurately. In the present study, a modeling technique of RWA and its disturbance was described. The micro-vibration disturbances were generated numerically by using an analytical wheel and disturbance model. The parameter estimation scheme of the model was suggested, and the RWA and disturbance modeling technique was verified through the numerical example analysis. The analytical results show that the wheel and disturbance model can be accurately established by using the modeling technique proposed in the present study. The wheel and disturbance model is expected to be useful for development of the RWA isolator system.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.1
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• pp.72-82
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• 2023

The EOTS(Electro Optical Tracking System) must have stabilization performance to provide high-quality images under disturbance environment. In this paper, we present a controller that can minimize the LOS error and has a simple structure. Hence, to evaluate the performance of this controller, analysis in the frequency domain and LOS error measurement are performed. In order to measure the LOS error without a 'rate table' that requires a lot of facility investment, we propose a design method for disturbance model that considers the operating environment of the EOTS. Finally, the performance of the stabilization algorithm is evaluated by the proposed disturbance model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.109-116
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• 2008

Model matching problem of asynchronous sequential machines is addressed in this paper. The main topic is to design a corrective controller such that the closed-loop behavior of the asynchronous sequential machine can follow a given model, i.e., their models can be "matched" in stable states. In particular, we assume that the considered asynchronous machine suffers from the presence of an input disturbance that can cause undesirable state transitions. The proposed controller can realize both model matching and elimination of the adverse effect of the input disturbance. Necessary and sufficient condition for the existence of a corrective controller that solves model matching problem is presented. Whenever controller exists, algorithms for their design are outlined and demonstrated in a case study.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.387-387
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• 2000

In this paper, we present a model reference sliding mode control for the system with input/output disturbance. The proposed model reference sliding mode control makes always the error remain on the surface in finite time. Therefore the system is insensitive to external disturbance. Simulation results are included to illustrate the effectiveness of proposed scheme.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.552-557
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• 2004

This paper presents a disturbance observer based on an $H_{\infty}$ controller synthesis for the trajectory control of a hydraulic excavator. Compared to conventional robot manipulators driven by electrical motors, the hydraulic excavator has more nonlinear and coupled dynamics. In particular, the interactions between an excavation tool and the materials being excavated are unstructured and complex. In addition, its operating modes depend on working conditions, which make it difficult to not only derive the exact mathematical model but also design a controller systematically. In this study, the approximated linear model obtained through off-line system identification is used as nominal plant model for a disturbance observer. A disturbance observer based tracking controller which considers the effect of disturbance and model uncertainty is synthesized in $H_{\infty}$ frameworks. Simulation results are used to demonstrate the applicability of the proposed control scheme.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.2
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• pp.127-134
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• 2021

This study presents an overhang-type rail traction system using dual brushless AC (BLAC) motors with hall sensors. For an accurate position and moving length control of the designed rail traction system, instantaneous position controller using speed reference model and modified disturbance observer for BLAC motor with hall sensor are proposed. The presented speed reference model is designed to satisfy the required performance of 200 mm/s with proper acceleration and deceleration slopes to reduce mechanical vibration. Through the instantaneous speed reference model, instantaneous position and speed errors can be compensated together. Furthermore, the modified disturbance observer for BLAC motors with low-resolution hall sensors can improve the torque and speed control performance. The proposed disturbance observer is based on an actual motor speed. However, the feedback speed information of the hall sensor is not enough for use in the low-speed region. The practical adopted disturbance observer uses an activation speed band to the actual torque controller of the designed rail traction system. The proposed position control scheme is verified by the MATLAB-Simulink model and a practical manufactured traction system. In the computer simulation and experiments, the proposed position control scheme shows advanced control performance.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.11
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• pp.100-107
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• 2003

This paper represents a disturbance compensation control for attenuating disturbance responses. In the consideration of the requirements on the model accuracy in the model based compensator designs, an experimental feed forward compensator design based on adaptive estimation by Filtered-x least mean square (FXLMS) algorithm is proposed. The convergence properties of the FXLMS algorithm are discussed and its conditions for the asymptotic convergence are derived theoretically. The effectiveness of the proposed method and the theoretical proof are verified by computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1209-1212
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• 1996

In this paper, we design a stabilizing controller with disturbance rejection properties for multirate sampled-data systems which have periodic output measurement scheme. We assume that the plant is open-loop unstable and the disturbance consists of a sum of finite number of sine waves with different frequencies. A sufficient condition for maintaining observability in multirate sampled-data systems is derived. The proposed controller has an IMC structure and can be decomposed into the filtered-disturbance estimator and the inverse of the fast uniform sampled model of the pre-stabilized plant. An example is presented for illustrations.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.2
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• pp.159-167
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• 1999

A digital tracking controller is proposed for a precise positioning control under a large repetitive and/or non repetitive disturbances. The proposed control system. Numerical Examples are illustrated for a precise head positioning of optical disk drives regardless of a torque disturbance and/or output disturbance.