Sangwon Lee / Hyungbo Shim Actuator Position Estimation for Electro-Hydraulic Ride Height Control System Using EKF and a Reduced-Order Model Obtained via Singular Perturbation Proceedings Article In: Institute of Control, Robotics and Systems 2025 25th International Conference on Control, Automation and Systems (ICCAS), Songdo Convensia, Incheon, Korea, 2025. @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}
}
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. |
Junsoo Kim / Jin Gyu Lee / Henrik Sandberg / Karl H. Johansson Complexity Reduction for Resilient State Estimation of Uniformly Observable Nonlinear Systems Journal Article In: IEEE TRANSACTIONS ON AUTOMATIC CONTROL, vol. 70, iss. 2, pp. 1267-1272, 2025, ISSN: 0018-9286. @article{nokey,
title = {Complexity Reduction for Resilient State Estimation of Uniformly Observable Nonlinear Systems},
author = {Junsoo Kim and Jin Gyu Lee and Henrik Sandberg and Karl H. Johansson},
doi = {10.1109/TAC.2024.3459413},
issn = {0018-9286},
year = {2025},
date = {2025-02-01},
urldate = {2025-02-01},
journal = {IEEE TRANSACTIONS ON AUTOMATIC CONTROL},
volume = {70},
issue = {2},
pages = {1267-1272},
abstract = {A resilient state estimation scheme for uniformly observable nonlinear systems, based on a method for local identification of sensor attacks, is presented. The estimation problem is combinatorial in nature, and so many methods require substantial computational and storage resources as the number of sensors increases. To reduce the complexity, the proposed method performs the attack identification with local subsets of the measurements, not with the set of all measurements. A condition for nonlinear attack identification is introduced as a relaxed version of existing redundant observability condition. It is shown that an attack identification can be performed even when the entire state cannot be recovered from the measurements. As a result, although a portion of measurements are compromised, they can be locally identified and excluded from the state estimation, and thus, the true state can be recovered. Simulation results demonstrate the effectiveness of the proposed scheme.},
keywords = {Estimation theory, Nonlinear system, Observability},
pubstate = {published},
tppubtype = {article}
}
A resilient state estimation scheme for uniformly observable nonlinear systems, based on a method for local identification of sensor attacks, is presented. The estimation problem is combinatorial in nature, and so many methods require substantial computational and storage resources as the number of sensors increases. To reduce the complexity, the proposed method performs the attack identification with local subsets of the measurements, not with the set of all measurements. A condition for nonlinear attack identification is introduced as a relaxed version of existing redundant observability condition. It is shown that an attack identification can be performed even when the entire state cannot be recovered from the measurements. As a result, although a portion of measurements are compromised, they can be locally identified and excluded from the state estimation, and thus, the true state can be recovered. Simulation results demonstrate the effectiveness of the proposed scheme. |
Chanhwa Lee / Zhaowu Ping / Hyungbo Shim On-line Switching Signal Estimation of Switched Linear Systems with Measurement Noise Proceedings Article In: In this paper, we study a switching signal estimation problem for continuous time switched linear control systems with measurement noise. Inspired by the work of [8], we first propose a generalized minimum distance criterion to estimate the active mode of the plant with inputs. Then we propose an implementable on-line robust switching signal estimation algorithm to detect the switching time with guaranteed precision, where some update condition and threshold condition are checked all the time. Under the update and threshold conditions, we detect the switching time within a predetermined time interval after the switching occurred., pp. 2180-2185, IEEE, Zurich, Switzerland, 2013. @inproceedings{LeePingShim13,
title = {On-line Switching Signal Estimation of Switched Linear Systems with Measurement Noise},
author = {Chanhwa Lee and Zhaowu Ping and Hyungbo Shim},
doi = {10.23919/ECC.2013.6669442},
year = {2013},
date = {2013-07-17},
booktitle = {In this paper, we study a switching signal estimation problem for continuous time switched linear control systems with measurement noise. Inspired by the work of [8], we first propose a generalized minimum distance criterion to estimate the active mode of the plant with inputs. Then we propose an implementable on-line robust switching signal estimation algorithm to detect the switching time with guaranteed precision, where some update condition and threshold condition are checked all the time. Under the update and threshold conditions, we detect the switching time within a predetermined time interval after the switching occurred.},
pages = {2180-2185},
publisher = {IEEE},
address = {Zurich, Switzerland},
abstract = {In this paper, we study a switching signal estimation problem for continuous time switched linear control systems with measurement noise. Inspired by the work of [8], we first propose a generalized minimum distance criterion to estimate the active mode of the plant with inputs. Then we propose an implementable on-line robust switching signal estimation algorithm to detect the switching time with guaranteed precision, where some update condition and threshold condition are checked all the time. Under the update and threshold conditions, we detect the switching time within a predetermined time interval after the switching occurred.},
keywords = {Estimation theory, Linear system},
pubstate = {published},
tppubtype = {inproceedings}
}
In this paper, we study a switching signal estimation problem for continuous time switched linear control systems with measurement noise. Inspired by the work of [8], we first propose a generalized minimum distance criterion to estimate the active mode of the plant with inputs. Then we propose an implementable on-line robust switching signal estimation algorithm to detect the switching time with guaranteed precision, where some update condition and threshold condition are checked all the time. Under the update and threshold conditions, we detect the switching time within a predetermined time interval after the switching occurred. |