• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.2
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• pp.200-206
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• 1991

In this paper, an output feedback is used to reduce the effect of the vibration in the control of a flexible one-link robot arm. A PD control method with a time varying gain is proposed to improve the performance of the system in tip deflection and settling time for the step reference input. By making the change of feedback gain smoothly, th input torque can be made smooth. When there is a payload with unknown mass, an interpolation method which uses the inrehgrated value of the transient response of the hub angle is proposed for the estimation of teh payload mass. This method can be used when the reference input is known and we can get highly accurate estimate for the unknown payload. It is also demonstrated that flexible one-link arm can be controlled prettry accurately by an output feedback in a noisy environment without knowing the mass of the payload.

• Journal of Aerospace System Engineering
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• v.5 no.2
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• pp.8-11
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• 2011

The scope of this paper is to show a risk management plan including how to perform risk assessment and to make a mitigation plan aspects of the communication payload system development. According to system engineering management guide of DoD of USA and risk management plan of satellite communication system, risk assessment and mitigation plan of communication payload system were performed. In this paper, it is indicated the process of risk management and risk assessment procedures as well as mathematical model for risk assessment of DoD guide. It is shown how risk assessment and mitigation plan have implemented in communication payload system development through case study.

• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.71-75
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• 2006

This paper describes operation plans for satellite communications system (SATCOM) which is consisted of Ka band communication payload, geostationary satellite control system and communication test earth station system for the communication, ocean and meteorological satellite system (COMS). Also this paper describes the communication service and mission plans by each system of the SATCOM, and configurations and functions of the system interface between each system. Especially this paper proposes operational items, functions and their configuration diagrams, touches their operational plans. This paper describes function definitions, configuration diagram and operation plans of the PCS )Payload Control System) for monitor and control of the communication payload and communication service network of the SATCOM.

• Journal of the Korea Convergence Society
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• v.8 no.3
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• pp.23-30
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• 2017

OpenADR is a national standard communication protocol of demand response service. OpenADR uses XML message, called a payload, to support logical transaction of demand response service. For this purpose, OpenADR defines a XML element as transaction identifier which is called requestID. Unfortunately, OpenADR 2.0b profile specification describes some information about requestID but, it is not enough for understanding properly. Ambiguous definition of payload transaction makes vulnerabilities of implementing VEN & VTN and confuses mapping OpenADR 2.0b protocol into other smart grid protocols. Therefore, this paper redefines payload transaction to solve an ambiguous information of OpenADR 2.0b profile specification, proposes a model of analyzing payload transaction, and shows how to detect a payload transaction vulnerability in real-world.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.9
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• pp.749-757
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• 2021

In transportation missions using quadrotor, the payload may change the model parameters, such as mass, moment of inertia, and center of gravity. Moreover, if position of the payload is constantly changing during flight, the effect can adversely affect the control performances. To handle this issue, we suggest Model Reference Adaptive Control based on Linear Quadratic Regulator(LQR+MRAC) to compensate the uncertainty caused by payload. Firstly, the mathematical modeling with the fixed payload is derived. Second, Linear Quadratic Regulator (LQR) is used to design the reference model and baseline controller. Also, through the Stability method, Adaptive law is derived to estimate the model parameters. To verify the performance of proposed control scheme, we compared LQR and LQR+MRAC in situations where uncertainties exist. And, when the disturbance exist, the classic MRAC and proposed controller is compared to analyze the transient response and robustness.

• Journal of Astronomy and Space Sciences
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• v.20 no.4
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• pp.339-350
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• 2003

Engineering qualification model payload for a communications and broadcasting satellite(CBS) was developed by ETRI from May, 2000 to April, 2003. For. the purpose of functional test and verification of the payload, a real-time hardware-in-the-loop(HITL) CBS simulator(CBSSIM) was also developed. We assumed that the spacecraft platform for the CBSSIM is a geostationary communication satellite using momentum bias three-axis stabilization control technique based on Koreasat. The payload hardware is combined with CBSSIM via Power, Command and Telemetry System(PCTS) of Electrical Ground Support Equipment(EGSE). CBSSIM is connected with PCTS by TCP/IP and the payload is combined with PCTS by MIL-STD-1553B protocol and DC harness. This simulator runs under the PC-based simulation environment with Windows 2000 operating system. The satellite commands from the operators are transferred to the payload or bus subsystem models through the real-time process block in the simulator. Design requirements of the CBSSIM are to operate in real-time and generate telemetry. CBSSIM provides various graphic monitoring interfaces and control functions and supports both pre-launch and after-launch of a communication satellite system. In this paper, the HITL simulator system including CBSSIM, communications payload and PCTS as the medium of interface between CBSSIM and communications payload will be described in aspects of the system architecture, spacecraft models, and simulator operation environment.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.22.1-22.1
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• 2005

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.34-37
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• 1994

A satellite communications monitoring and control system(SCMCS) has been developed at ETRI to provide the capabilities of in-orbit test (IOT) for communications payload and communications system monitoring(CSM) for the satellite communications services. The paper discusses the system level design of SCMCS and its tasks.

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.90-93
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.445-446
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• 2011