• Journal of Electrical Engineering and Technology
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• v.10 no.6
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• pp.2393-2405
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• 2015

This paper considers a decentralized multiple faults detection and isolation (FDI) scheme for reconfigurable manipulators. Inspired by their modularization property, a global sliding mode (GSM) based stable adaptive fuzzy decentralized controller is investigated for the system in fault free, while for the system suffering from multiple faults (actuator fault and sensor fault), the decentralized sliding mode observer (DSMO) is employed to detect their occurrence. Hereafter, the time and location of faults can be determined by a fault isolation scheme via a bank of DSMOs. Finally, the effectiveness of the proposed schemes in controlling, detecting and isolating faults is illustrated by the simulations of two 3-DOF reconfigurable manipulators with different configurations successfully.

• International Journal of Control, Automation, and Systems
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• v.6 no.2
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• pp.149-159
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• 2008

This paper considers the problem of adaptive fault-tolerant guaranteed cost controller design via dynamic output feedback for a class of linear time-delay systems against actuator faults. A new variable gain controller is established, whose gains are tuned by the designed adaptive laws. More relaxed sufficient conditions are derived in terms of linear matrix inequalities (LMIs), compared with the corresponding fault-tolerant controller with fixed gains. A real application example about river pollution process is presented to show the effectiveness of the proposed method.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.9
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• pp.627-638
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• 2022

This paper discusses the utilization of fault-tolerant technology in the industry by analyzing the status of drone failures in the unmanned vehicle industry survey conducted in 2020. Based on the survey results of the domestic unmanned vehicle industry, we identify subsystems with high fault rates and high severity when faults occur. In addition, fault simulations of the identified subsystems are conducted to analyze the effect of the fault on the vehicles. After that, the fault diagnosis and fault compensation methods studied so far are reviewed, and research cases of the methods are examined. Moreover, the ways to apply it to actual fault cases in the unmanned vehicle industry are debated. Furthermore, based on the previous discussion, the fault-tolerant system is presented, and the consideration when designing the fault-tolerant system in the industry are studied.

• Journal of Applied Reliability
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• v.12 no.2
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• pp.121-129
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• 2012

This paper deals with a design of reliable state feedback controllers for continuous time polynomial systems with actuator failures. The goal is to find an asymptotically stabilizing controller such that the closed loop system achieves the prescribed decay rate in the actuator failure cases. Based on a sum of squares (SOS) approach, a design method for reliable nonlinear controller is presented. In order to demonstrate our design method, a numerical example is shown.

• Journal of Hydrospace Technology
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• v.1 no.1
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• pp.75-88
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• 1995

Auto-Pilot System uses heading angle information via the position sensor and the rudder device to control the ship's direction. Most of the control logics are composed of the state estimation and control algorithms assuming that the measurement device and the actuator have no fault except the measurement noise. But such asumptions could bring the danger in real situation. For example, if the heading angle measuring device is out of order the control action based on those false position information could bring serious safety problem. In this study, the control system including improved method for processing the position information is applied to the Auto-Pilot System. To show the difference between general state estimator and F.D.F., BJDFs for the sensor and the actuator failure detection are designed and the performance are tested. And it is shown that bias error in sensor could be detected by state-augmented estimator. So the residual confined in the 2-dimension in the presence of the sensor failure could be unidirectional in output space and bias sensor error is much easier to be detected.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.4
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• pp.8-16
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• 1993

Auto-Pilot System uses heading angle information via the position sensor and the rudder device to control the ship direction. Most of the control logics are composed of the state estimation and control algorithms assuming that the measurement device and the actuator have no fault except the measurement noise. But such asumptions could bring the danger in real situation. For example, if the heading angle measuring device is out of order the control action based on those false position information could bring serious safety problem. In this study, the control system including improved method for processing the position information is applied to the Auto-Pilot System. To show the difference between general state estimator and F.D.F., BJDFs for the sensor and the actuator failure detection are designed and the performance are tested. And it is shown that bias error in sensor could be detected by state-augmented estimator. So the residual confined in the 2-dim in the presence of the sensor failure could be unidirectional in output space and bias sensor error is much easier to be detected.

• Advances in aircraft and spacecraft science
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• v.5 no.4
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• pp.459-475
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• 2018

In the field of aerospace engineering, accurate control of a spacecraft's orientation is often very important to mission success. Therefore, attitude control is a technically plentiful and extensively studied subject in controls literature during recent decades. This investigation of spacecraft attitude control is assumed to address two important aspects of the problem solutions. One sliding mode anti-disturbance control for utilization of faulty actuator components and another one disturbance observer based control to improve the pointing accuracy in the absence of anti-vibration equipment for the elastic appendages like a solar panel. Simultaneous occurrence of vibration due to flexible appendages and reaction degradation due to failure in attitude actuators complicates this case. The advantage of this method is acquisition proper control by the combination of disturbance observer and sliding mode compensation that form a fault tolerant control for the concerned satellite attitude control system. Furthermore, the proposed composite method indicates that occurrence the failure in actuators and even elastic solar panel vibration effect may be handled directly without reconfiguring the control components or providing piezoelectric devices. It's noteworthy, attitude quaternion and angular velocity commands are robustly tracked via controllers to become inclined to zero.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1853-1856
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• 2003

This paper considers the problem of longitudinal control of a platoon of automotive vehicles on a straight lane of a highway and proposes control laws in the event of loss of communication between the lead vehicle and the other vehicles in the platoon. Since safety plays a key role in the development of an Automated Highway System, fault-tolerant control is vital. In this paper, we develop a control algorithm in vehicle platooning and prove that this control algorithm is stable for certain class of faults such as parameter uncertainties. The performance of the controller is demonstrated through a series of simulations incorporating various vehicles and AHS faults. Results of simulation shows that the vehicles have good performance in spite of simple automotive and AHS failure, such as actuator failure,that is to say, engine input failure, communication failure between lead vehicle and the another vehicles.

• International Journal of Control, Automation, and Systems
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• v.5 no.6
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• pp.707-711
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• 2007

An observer-based fault tolerant control (FTC) method is proposed for constrained switched systems (CSS) with input constraints. A family of Lyapunov-based bounded controllers are designed to ensure that, whenever actuator faults occur at the dwell time period of each continuous mode, the mode is always within its corresponding stability region. A set of switching laws are designed to guarantee the asymptotic stability of the overall CSS. The fixed stability regions on which the FTC method is based are also relaxed by the proposed variable stability regions. An example of CPU processing illustrates the effectiveness of proposed method.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.1037-1040
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• 1998

In this research a fault-tolerant and bumpless switching control is proposed for boiler systems used in the power plants. Firstly, three operating points are selected to control the nonlinear boiler through the full operational range, and the $H_{\infty}$ loop shaping controller and the model-based predictive controller(MBPC) are designed. To prevent the windup and bump problems which are caused by the actuator saturation and the controller switching, an anti-windup and bumpless transfer technique is adopted to the $H_{\infty}$ loop shaping controller. Also the constrained gain-scheduling technique is applied to MBPC to achieve the same objective. Secondly, the fault-tolerant control technique is proposed to continue the control action without stopping the boiler operation even in case of some faults. Through various simulation studies, the performances of the proposed control techniques are demonstrated.