• Journal of Institute of Control, Robotics and Systems
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• v.11 no.12
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• pp.1002-1010
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• 2005

We study on the implementation of reconfigurable position control system which is based on Open Control Platform(OCP) for Unmanned Expedition Vehicles(UEV) in ubiquitous environment. The control system uses hierarchical control structure and OCP structure which contains three layers such as core OCP, reconfigurable control API(Application Programmer Interface), generic hybrid control API. The goal of our research is to implement an UEV control system using advanced software technology. As a specific control problem, we study a transition management problem between PID control and neural network control depending on fault or parameter change of the plant, i.e., UEV. The concept of the OCP-based software-enabled control can provide synergy effect by the integration of software component, middleware, network communication, and control, and thus can be applied to various systems in ubiquitous environment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.381-391
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• 2010

In this paper, a novel frequency reconfigurable active array antenna(RAA) system, which can be reconfigurable for three reconfigurable frequency bands, is proposed by using commercial RF MEMS switches. The MEMS switch shows excellent insertion loss, linearity, as well as isolation. So, the system performance degradation of the reconfigurable system by using MEMS switches can be minimized. The proposed frequency reconfigurable active antenna system is consisted with the noble frequency reconfigurable front-end amplifiers(RFA) with the simple reconfigurable impedance matching circuits(RMC), reconfigurable antenna elements(RAE), as well as a reconfiguration control board(RCB) for MEMS switch control. The proposed RAA system can be reconfigurable for three frequency bands, 850 MHz, 1.9 GHz, and 3.4 GHz, with $2{\times}2$ array of the RAE having broadband printed dipole antenna topology. The validity of the proposed RFA as well as RAA is also presented with the experimental results of the fabricated systems.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.2
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• pp.99-106
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• 2003

A new reconfigurable model following flight control method based on direct adaptive scheme is presented. Using the timescale separation principle, both the inner-loop and the outer-loop states are controlled simultaneously. For the timescale separation assumption to be satisfied, the inner-loop model dynamics is set to be fast whereas the outer-loop model dynamics is set to be relatively slow. The stability and convergence of the proposed control law is proved by Lyapunov theorem. One of the merits of the proposed reconfigurable controller is that the FDI process and the persistent input excitation are not necessary, which is suitable for the flight control system. To evaluate the reconfiguration performance of the proposed control method, numerical simulation is performed using six degree-of-freedom nonlinear dynamics.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.5
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• pp.422-428
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• 2007

This paper presents a neural network based adaptive control approach to a reconfigurable flight control law that keeps handling qualities in the presence of faults or failures to the control surfaces of an aircraft. This approach removes the need for system identification for control reallocation after a failure and the need for an accurate aerodynamic database for flight control design, thereby reducing the cost and time required to develope a reconfigurable flight controller. Neural networks address the problem caused by uncertainties in modeling an aircraft and pseudo control hedging deals with the nonlinearity in actuators and the reconfiguration of a flight controller. The effect of the reconfigurable flight control law is illustrated in results of a nonlinear simulation of an unmanned aerial vehicle Durumi-II.

• 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.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.40.2-40
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• 2002

This paper presents the reconfigurable flight controller in the presence of jammed actuator fault using the adaptive sliding mode control scheme. It is developed under the assumption that the control surface fault cannot be detected and the positions of stuck control surfaces are unknown. It is well known that sliding mode controller shows good performance for the systems with various uncertainties. None-operating stuck actuator makes the system behave like bias which degrades the system performance and sometimes destabilizes the system. Therefore, the bias term generated by actuator faults has to be compensated by the control system. To the objective, we adopt the adaptive sliding mode cont...

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.418-429
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• 2018

This paper studies the decentralized position/force control problem for constrained reconfigurable manipulator without torque sensing. A novel joint torque estimation scheme that exploits the existing structural elasticity of the manipulator joint with harmonic drive model is applied for each joint module. Based on the estimated joint torque and dynamic output feedback technique, a decentralized position/force control strategy is presented. In order to solve the problem of controller parameter perturbation, the non-fragile robust technique is introduced into the dynamic output feedback controller. Subsequently, the stability of the closed-loop system is proved using the Lyapunov theory and linear matrix inequality (LMI) technique. Finally, two 2-DOF constrained reconfigurable manipulators with different configurations are applied to verify the effectiveness of the proposed control scheme in numerical simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.3
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• pp.261-266
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• 2004

Recently, a variety of intelligent robots are developed for the personal purpose beyond the industrial application. These intelligent robots have ranges of sensors, actuators, and control algorithms to their application. In this paper we propose a reconfigurable robot controller, $SR^2$c (The SOPC-based Reconfigurable Robot Controller), based on SOPC (System on a Programmable Chip), that can be reconfigurable easily by software. The proposed robot controller contains not only a processing module but also robot-specific IP's. To show a feasibility of the proposed robot controller, a small entertainment robot, Wizard-4 is implemented with a single chip controller as proposed in this paper.

• International Journal of Safety
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• v.10 no.2
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• pp.10-15
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• 2011

The reconfigurable control systems based on feedback controls are utilized to compensate for damages of actuators in control systems. Such systems have multiple feedback controls and switch them in accordance with the degrees of the failures of the actuators. In order to be able to assess those systems, this paper develops a method to obtain reliabilities of reconfigurable dynamical systems which are interconnected in parallel / series configuration. By calculating reliabilities of interconnected dynamical systems, it is possible to assess many dynamical systems by comparing their reliabilities. Firstly, reliabilities of subsystems are obtained according to the definitions of the failures in terms of robust reliability for each subsystem. Then, the reliability of overall system is calculated from reliabilities of subsystems, using the methodology employed for probabilistic safety assessment. Failure rates of subsystems with feedbacks for reconfiguration change in certain time periods because of the switching of feedback controls. In order to deal with this, combinations of subsystems which compose overall system for each time period are derived by the methodology mentioned above and then integrated to calculate the reliability of overall system for a specific time. An illustrative example shows the validity and details of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.7
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• pp.775-782
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• 2016

In this paper, we presented the paper-based reconfigurable frequency selective surface(FSS) for transmitting or blocking the wireless LAN signal in indoor environments. The proposed reconfigurable FSS are designed on coated paper using a printing of conductive ink and conductive adhesive for PIN diode, which provides ON/OFF of the reconfigurable FSS for passing or blocking the 5GHz signal. The reconfigurable FSS attached on the wall can pass or block the incident wireless signal as the received signal strength in indoor. To provide the validity of the proposed FSS, we fabricated the reconfigurable FSS on the paper and confirmed the very similar results between simulations and measurements. From the measured results of the proposed spectrum control system, we know that the proposed reconfigurable FSS can block about 20dB at 5.745GHz~5.805GHz.