• Journal of Auto-vehicle Safety Association
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• v.11 no.2
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• pp.11-16
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• 2019

This paper suggests an algorithm for detecting fault of longitudinal controller in autonomous vehicles. Guaranteeing safety in fault situation is essential because electronic devices in vehicle are dependent each other. Several methods like alarm to driver, ceding control to driver, and emergency stop are considered to cope with fault. This research investigates the fault monitoring process in fail-safe system, for controller which is responsible for accelerating and decelerating control in vehicle. Residual is computed using desired acceleration control command and actual acceleration, and detection of its abnormal increase leads to the decision that system has fault. Before computing residual for controller, health monitoring process of acceleration signal is performed using hardware and analytic redundancy. In fault monitoring process for controller, a process model which is fitted using driving data is considered to improve the performance. This algorithm is simulated via MATLAB tool to verify performance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.66-73
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• 2024

Stay-cable is one of the most important load carrying members in cable-stayed bridges. Monitoring structural integrity of stay-cables is crucial for evaluating the structural condition of the cable-stayed bridge. For stay-cables, tension and damping ratio are estimated based on modal properties as a measure of structural integrity. Since the monitoring system continuously measures the vibration for the long-term period, data acquisition systems should be stable and power-efficiency as the hardware system. In addition, massive signals from the data acquisition systems are continuously generated, so that automated analysis system should be indispensable. In order to fulfill these purpose simultaneously, this study presents an autonomous cable monitoring system based on domain-knowledge using IoT for continuous cable monitoring systems of cable-stayed bridges. An IoT system was developed to provide effective and power-efficient data acquisition and on-board processing capability for Edge-computing. Automated peak-picking algorithm using domain knowledge was embedded to the IoT system in order to analyze massive data from continuous monitoring automatically and reliably. To evaluate its operational performance in real fields, the developed autonomous monitoring system has been installed on a cable-stayed bridge in Korea. The operational performance are confirmed and validated by comparing with the existing system in terms of data transmission rates, accuracy and efficiency of tension estimation.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.417-420
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• 2004

Recently, the applications of unmanned system are steadily increasing. Unmanned automatic system is suitable for routine mission such as reconnaissance, environment monitoring, resource conservation and investigation. Especially, for the ocean environment monitoring mission, many ocean engineers had scoped with the routine and even risky works. The automatic system can replace the periodic and routine missions: water sampling, temperature and salinity measuring, etc. In this paper, an unmanned surface vessel was designed for routine and periodic ocean environmental missions. An autonomous control system was designed and tested for the unmanned vessel. A GPS and gyro compass was used for navigation. A linear autopilot model for course control can be derived from the maneuvering model. Nomoto's 2nd-order response equation was derived. The design methodologies and performance of the surface vessel were illustrated and verified with this linearized equation of motion. A linear controller was designed and automatic route tracking performance was verified for yaw subsystem.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.937-945
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• 2022

Maritime autonomous surface ships (MASS) have a high degree of autonomy and operate autonomously along a planned route. However, when necessary, the shore remote control center(SRCC) can directly intervene in ship operations. In this paper, the operation concept of the simulator system, which can be used to educate and train shore remote control officers, responsible for monitoring the operation of autonomous ships on land and remotely controlling them in case of an emergency, is reviewed. The required functions of the simulator system that enables the operation concept are also reviewed. The major parts of the SRCC simulator system are the monitoring station and control station, which simulate the functions of monitoring the operation status of multiple MASS and the functions of the remote operation of MASS in the case of emergency, respectively. Various units to simulate the operation of MASS and traf ic ships and various objects around the MASS are included in the simulator system. The instructor operation station is the central part of the simulator system that integrates and controls the unit systems. Functionally, as conditions under which SRCC is allowed to remotely intervene in the operation of MASS, the emergency situation for remote control (ESRC) has been defined. Moreover, the required functions to cope with these ESRC conditions have been included in the simulator system requirements.

• Journal of Positioning, Navigation, and Timing
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• v.10 no.4
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• pp.341-351
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• 2021

In this paper, a GNSS error generation simulator for Signal Quality Monitoring (SQM) is implemented by using Matlab based on mathematical models derived from the effect of GNSS signal and measurement errors. The GNSS signal measurement errors of interest in this paper include three cases such as Evil Wave Form (EWF), Multipath (MP) and Radio Frequency Interference (RFI). In order to verify the validity of the generated measurement errors, a simple form of metrics for detecting and monitoring GNSS errors is included in the simulator. The GNSS errors generated by the simulator are added to the GNSS measurement data from commercial GNSS receiver in real time, and then, the SQM is tested for various scenarios of each case configured by scenario setting of the user.

• JSTS:Journal of Semiconductor Technology and Science
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• v.5 no.4
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• pp.243-248
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• 2005

The UAV (Unmanned Aerial Vehicle) systems like unmanned autonomous helicopters are used in various missions of flight navigation and used to collect the environmental information of the surroundings. To realize the full functionalities of the UAV, the software part becomes a challenging problem. In this paper embedded real-time software architecture for unmanned autonomous helicopter is proposed that guarantee real-time performance of hard-real time tasks and re-configurability of soft-real time and non-real time tasks. The proposed software architecture has four layers: hardware, execution, service agent and remote user interface layer according to the reactiveness level for external events. In addition, the layered separation of concurrent tasks makes different kinds of mission reconfiguration possible in the system. An Unmanned autonomous helicopter system was implemented (Kyosho RC Helicopter) in our lab to test and evaluate the performance of the proposed system.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.311-318
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• 2003

Traffic management means the management of streams of people, vehicle and cargo. Its aim is to help creating an efficient, safe and environmentally friendly transport system. Traffic management can roughly be divided in traffic control and monitoring, traffic information and demand management. The main purpose of this thesis is providing the basis for developing the next generation train traffic management system by comparing domestic and abroad train traffic management system. The composition of this thesis has been discussed in the following order of the comparison of train traffic management system's function, the introduction of Autonomous Decentralized system, the comparison between CTC and ATOS. the comparison between the hierarchy system and Autonomous Decentralized system, the study of introduction plan of Autonomous Decentralized-type train traffic management system and conclusion.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.105-110
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• 2008

Unmanned helicopter has several abilities such as vertical take off, hovering, low speed flight at a specific altitude. Such vehicles are becoming popular in actual applications such as search and rescue, aerial reconnaissance and surveillance in the case of a large size disaster and forest fire. In this paper, a flight control system was designed for an unmanned helicopter. This paper was concentrated on describing the systematic design, electronic equipments and their interconnections for realizing the autonomous flight and aerial monitoring. A study on the autonomous waypoint navigation and altitude control performance were performed and tested on a test unmanned helicopter and the performance and the feasibility were represented.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.6
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• pp.222-234
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• 2020

Autonomous vehicles are equipped with a wide rage of sensors such as GPS, RADAR, LIDAR, camera, IMU, etc. and are driven by recognizing and judging various transportation systems at intersections in the city. The accident ratio of the intersection of the autonomous vehicles is 88% of all accidents due to the limitation of prediction and judgment of an area outside the sensing distance. Not only research on non-signalized intersection collision avoidance strategies through V2V and V2I is underway, but also research on safe intersection driving in failure situations is underway, but verification and fragments through simple intersection scenarios Only typical V2V failures are presented. In this paper, we analyzed the architecture of the V2V module, analyzed the causal factors for each V2V module, and defined the failure mode. We presented intersection scenarios for various road conditions and traffic volumes. we used the ISO-26262 Part3 Process and performed HARA (Hazard Analysis and Risk Assessment) to analyze the risk of autonomous vehicle based on the simulation. We presented ASIL, which is the result of risk analysis, proposed a monitoring concept for each component of the V2V module, and presented monitoring coverage.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.45-51
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• 2018

Autonomous ship has been sportlighted as a core technology for the maritime industry in Industry 4.0 era. Autonomous ship is expeected to improve the safety, reliability, efficiency and environment significantly. For the realization of the autonomous ship, the remote control of the ship is one of the core functionality in addition to the autonomous ship control functionality in a ship. In this paper, we address a autonomous ship control system based on remote control. This paper proposes a remote control autonomous system and standardized ship-to-shore remote control protocol with for open platform. Finally, we implemented the system and tested with a real experiments with the test ship in order to demonstrate the feasibility of the proposed remote control autonomous system.