• Journal of Institute of Control, Robotics and Systems
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• v.18 no.5
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• pp.433-438
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• 2012

In this paper, a operation network system equipped with onboard wireless communication systems and ground-based mission control systems is proposed for swarm flight of small UAVs. This operating system can be divided into two networks, UAV communication network and ground control system. The UAV communication network is intend to exchange the informations of navigation, mission and flight status with minimum time delay. The ground control system consisted of mission control systems and UDP network. Proposed operation network system can make a swarm flight of various UAVs, execute complex missions decentralizing mission to several UAVs and cooperte several missions. Finally, PILS environments are developed based on the total operating system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.6
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• pp.542-547
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• 2012

Until recently, most of GCS(Ground Control Software) has been required to visualize attitude, position, status of vehicle and to transmit control and mission commands for a single UAV(Unmanned Aerial Vehicle). However, the GCS needs to expand its functions to handle more complex situations. Simultaneous operation of multiple UAVs is emerging as a new practice. Hence, we set up requirements for operation of multiple UAVs and suggest the architecture of GCS that satisfy the requirements. In this study, we analyze the upper requirements and define the total structure of GCS at first. Then we design the inner structure for requirements in detail. Finally, we verify the functions of GCS on PILS(Processor In the Loop Simulation) System.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.9
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• pp.72-79
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• 2004

A method for thruster fault diagnosis for launch vehicle upper stage was developed. In order to protect the launch vehicle against the occurrence of faults, it is necessary to detect and identify the fault, as well as to reconfigure the controller of the vehicle. Considering the upper stage launch vehicle using reaction control system, an analytical method was adopted in order to detect the fault occurred in thruster. The fault detection scheme can be applied to the system regardless of the form of thruster fault occurred - leakage or lock-out. Results from processor-in-the-loop simulation are provided to demonstrate the validity of this fault detection and isolation scheme for the upper stage launch vehicle.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.2
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• pp.131-138
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• 2004

Automatic flight control system (AFCS) for a low-cost unmanned aerial vehicle is described in this paper. Development process and block diagram of the AFCS are introduced. The flight control law for longitudinal and lateral channel autopilot is designed using optimization process. In this procedure, the performance index is composed of desired location of closed loop system poles and H$_2$norm of the resultant flight control system. This procedure is applied to the autopilot design of an unmanned target vehicle. Performance of the AFCS is evaluated by processor-in-the-loop simulation test and flight test. These results show that the AFCS has acceptable performance fur low cost UAV.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.3
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• pp.181-192
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• 2022

Active vibration control system(AVCS) for helicopter enables to control the vibration generated from the main rotor and has the superb vibration reduction performance with low weight compared passive vibration reduction device. In this paper, FxLMS algorithm-based vibration control software of the light civil helicopter tansmits the control command calculated using the signals of the tachometer and accelerometers to the circular force generator(CFG) is developed and verified. According to the RTCA DO-178C/DO-331, the vibration control software is developed through the model based design technique, and real-time operation performance is evaluated in PILS(processor in-the loop simulation) and HILS(hardware in-the loop simulation) environments. In particular, the reliability of the software is improved through the LDRA-based verification coverage in the PIL environments. In order to AVCS to light civil helicopter(LCH), the dynamic response characteristic model is obtained through the ground/flight tests. AVCS configuration which exhibits the optimal performance is determined using system optimization analysis and flight test and obtain STC certification.

• Journal of Positioning, Navigation, and Timing
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• v.6 no.4
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• pp.195-203
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• 2017

A 2U cube satellite called SNUGLITE has been developed by GNSS Research Laboratory in Seoul National University. Its main mission is to perform actual operation by mounting dual-frequency global positioning system (GPS) receivers. Its scientific mission aims to observe space environments and collect data. It is essential for a cube satellite to control an Earth-oriented attitude for reliable and successful data transmission and reception. To this end, an attitude estimation and control algorithm, Attitude Determination and Control System (ADCS), has been implemented in the on-board computer (OBC) processor in real time. In this paper, the Extended Kalman Filter (EKF) was employed as the attitude estimation algorithm. For the attitude control technique, the Linear Quadratic Gaussian (LQG) was utilized. The algorithm was verified through the processor in the loop simulation (PILS) procedure. To validate the ADCS algorithm in the ground, the experimental verification via a single axis Hardware-in-the-loop simulation (HILS) was used due to the simplicity and cost effectiveness, rather than using the 3-axis HILS verification (Schwartz et al. 2003) with complex air-bearing mechanism design and high cost.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.172-178
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• 2009

Recently, autopilot is essential to reduce pilot's workload and increase flight safety. Avionics system of the small aircraft also has progressively adopted centralized multi-processor and multi-process computing architectures similar to the integrated modular avionics of B-777. It is increased more and more that importance of the flight control system. In this paper, the performance of the autopilot for the small aircraft has been verified with Hardware-In-the-Loop Simulation(HILS). Also, the autopilot algorithm that is operated in the Flight Control Computer(FCC) for the Fly by Wire(FBW) was verified with PILS and compared with the HILS results for the several commercial autopilots.