List of English Publication

@inproceedings{nokey,

title = {Actuator Position Estimation for Electro-Hydraulic Ride Height Control System Using EKF and a Reduced-Order Model Obtained via Singular Perturbation},

author = {Sangwon Lee and Hyungbo Shim},

doi = {10.23919/ICCAS66577.2025.11301191},

year  = {2025},

date = {2025-11-05},

urldate = {2025-11-05},

publisher = {2025 25th International Conference on Control, Automation and Systems (ICCAS)},

address = {Songdo Convensia, Incheon, Korea},

organization = {Institute of Control, Robotics and Systems},

abstract = {Ride height control systems adjust the distance between a vehicle's chassis and the road surface to improve ride comfort, aerodynamics, and underbody protection. Among various types, electro-hydraulic systems use hydraulic actuators to lift or lower the vehicle body. In such systems, ride height is usually measured by sensors mounted on the vehicle body. However, these sensors do not directly measure the actuator's internal position. As a result, the controller may continue commanding motion even after the actuator reaches its stroke limit. This can lead to noise generation, mechanical wear, and reduced ride quality. To solve this problem, we propose a model-based method to estimate the internal position of a single-acting actuator using only measurable signals. First, a full-order model of the system is developed, including the motor, pump, valves, and actuator dynamics. Then, a reduced-order model is derived using singular perturbation to simplify the computation. An extended Kalman filter is designed based on this reduced model. Simulation results are validated against experimental data obtained from vehicle-level tests. The proposed method shows accurate and robust performance under various operating conditions and sensor noise, making it suitable for practical ride height control systems.},

keywords = {Estimation theory, Extended Kalman Filter, Reduced order system, Singular perturbation},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{YunYangSeo12,

title = {Reduced-Order Dynamic Observer Error Linearization for Discrete-Time Systems},

author = {Hyeonjun Yun and Jongwook Yang and Jin Heon Seo},

doi = {10.1109/CDC.2012.6426824},

year  = {2012},

date = {2012-12-10},

booktitle = {Proc. of 2012 IEEE 51st Annual Conference on Decision and Control (CDC)},

pages = {4786-4791},

publisher = {IEEE},

address = {Maui, HI, USA},

abstract = {This paper addresses reduced-order dynamic observer error linearization (RDOEL) for discrete-time systems, which is a modified version of dynamic observer error linearization (DOEL). We define the concept of RDOEL and provide a necessary and sufficient condition for RDOEL. Moreover, we discuss the relation between RDOEL and DOEL when the auxiliary dynamics is an arbitrary linear controllable system. Using the relationship and an existing algorithm for DOEL, we also propose an algorithm for RDOEL that offers lower dimensional observers than DOEL. Finally, a simple example is included to illustrate the theory.},

keywords = {Reduced order system},

pubstate = {published},

tppubtype = {inproceedings}

}