• Journal of Mechanical Science and Technology
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• v.20 no.2
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• pp.278-285
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• 2006

The present study has been conducted to simulate dynamics of a gas engine-driven heat pump (GHP) for design of control algorithm. The dynamics modeling of a GHP was based on conservation laws of mass and energy. For automatic control of refrigerant pressures, actuators such as engine speed, outdoor fans, coolant three-way valves and liquid injection valves were PI or P controlled. The simulation results were found to be realistic enough to apply for control algorithm design. The model can be applied to build a virtual real-time GHP system so that it interfaces with a real controller in purpose of prototyping control algorithm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.10a
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• pp.5-18
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• 1993

This paper reports the recent trends in active vibration control in Japan, especially, based on papers selected in the Proceedings of First International Conference on Motion and Vibration Control (1st MOVIC) held at Yokohama, Japan on Sept.7-11, 1992. Firstly, it classifiers vibration control methods and vibration controllers, especially active dynamic absorbers which are widely used in mechanical and civil engineering. Secondly, it covers basic problems in the control of vibration of flexible structures such as formulating a reduced-order model required for designing vibration controller, proper arranging of sensors and actuators, and preventing of spillover instability. Finally, the practical use of control theories such as LQ control theory, $H^{\infty}$ control theory, neural network theory, and other topics are discussed..

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.12
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• pp.1278-1285
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• 2008

This paper presents an inertia type of piezostack based active mount fur unmanned aero vehicle (UAV) camera system. After identifying the stiffness and damping properties of the rubber element and piezostack a mechanical model of the active mount system is established. The governing equation of mount is then derived and expressed in a state space form. Subsequently, a sliding mode controller which is robust to uncertain parameters is designed in order to reduce the vibration imposed according to the military specification associated with UAV camera mount system operation. Control performances such as acceleration and transmitted force are evaluated through both computer simulation and experimental implementation.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.2
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• pp.93-102
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• 2005

The Nyquist robust stability margin is proposed as a measure of robust stability for systems with Affine TFM(Transfer Function Matrix) parametric uncertainty. The parametric uncertainty is modeled through a Affine TFM MIMO (Multi-Input Multi-Output) description with dead-time, and the unstructured uncertainty through a bounded perturbation of Affine polynomials. Gershgorin's theorem and concepts of diagonal dominance and GB(Gershgorin Bands) are extended to include model uncertainty. Multiloop PI/PID controllers can be tuned by using a modified version of the Ziegler-Nichols (ZN) relations. Consequently, this paper provides sufficient conditions for the robustness of Affine TFM MIMO uncertain systems with dead-time based on Rosenbrock's DNA. Simulation examples show the performance and efficiency of the proposed multiloop design method for Affine uncertain systems with dead-time.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.76.4-76
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• 2001

ESR(ElectroSlag Remelting) Process is secondary fine process and melts steels by electric resistance heat and fines the melting steels by an approproate solidification process. The final products are determined through the velocity of melting and the course of solidification in the process that is achieved by way of proper course of solidification. Thus, it is very important to monitor and control the process parameters which affects the melting and solidification process to get the high quality products. This paper describes a method to derive the mathematical model and analysis the dynamic characteristics for designing a controller of the ESR processes. The process consists of a melting and solidifying process and electrical system include the contact resistance mechanism ...

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.1-6
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• 2019

The purpose of this paper is to design a curtain control system for centralized management of large curtains, which includes curtain structure, electric curtain controller, communication system, user interface and remote control. Curtain structure is designed to avoid using limit switch. The system is based on microprocessor, determined the stop position and complete running time of electric curtain through time control, and achieved remote control of curtain opening and closing through wired and wireless communication modes. By establishment of a mathematical model to calculate the inertia compensation time of the electric curtain, the electric curtain can be stopped ahead of time, and the curtain can be completely closed by the inertia. The result of test experiment of 32 electric curtain controllers shows the communication success rate reached 100%.

• Smart Structures and Systems
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• v.26 no.6
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• pp.797-807
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• 2020

Due to the influence of nonlinearity and time-variation, it is difficult to establish an accurate model of concrete frame structures that adopt active controllers. Fuzzy theory is a relatively appropriate method but susceptible to human subjective experience to decrease the performance. This paper proposes a novel artificial intelligence based EBA (Evolved Bat Algorithm) controller with machine learning matched membership functions in the complex nonlinear system. The proposed affine transformed membership functions are adopted and stabilization and performance criterion of the closed-loop fuzzy systems are obtained through a new parametrized linear matrix inequality which is rearranged by machine learning affine matched membership functions. The trajectory of the closed-loop dithered system and that of the closed-loop fuzzy relaxed system can be made as close as desired. This enables us to get a rigorous prediction of stability of the closed-loop dithered system by establishing that of the closed-loop fuzzy relaxed system.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.2
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• pp.109-117
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• 2022

This paper proposes a method for detecting flight anomalies of drones through the difference between the command of flight controller (FC) and the navigation solution. If the drones make a flight normally, control errors generated by the difference between the desired control command of FC and the navigation solution should converge to zero. However, there is a risk of sudden change or divergence of control errors when the FC control feedback loop preset for the normal flight encounters interferences such as strong winds or navigation sensor abnormalities. In this paper, we propose the method with a deep neural network model that predicts the control error in the normal flight so that the abnormal flight state can be detected. The performance of proposed method was evaluated using the real-world flight data. The results showed that the method effectively detects anomalies in various situation.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.4
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• pp.34-40
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• 2008

This paper presents a vision based walking robot control system using hand shape recognition. To recognize hand shapes, the accurate hand boundary needs to be tracked in image obtained from moving camera. For this, we use an active contour model-based tracking approach with mean shift which reduces dependency of the active contour model to location of initial curve. The proposed system is composed of four modules: a hand detector, a hand tracker, a hand shape recognizer and a robot controller. The hand detector detects a skin color region, which has a specific shape, as hand in an image. Then, the hand tracking is performed using an active contour model with mean shift. Thereafter the hand shape recognition is performed using Hue moments. To assess the validity of the proposed system we tested the proposed system to a walking robot, RCB-1. The experimental results show the effectiveness of the proposed system.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.1
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• pp.101-107
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• 2001

The objective of this paper is to present a method for designing robust positioning control systems of a flexible arm using mixed $H_2/H_{\infty}$ and $\mu$ theory. We begin with a description of the flexible arm based on the model identification method and discuss the derivation of the model uncertainty. The validity of the obtained model is confirmed experimentally. Next, a robust controller is designed based on the mixed $H_2/H_{\infty}$ and $\mu$ theory by which we can improve robustness of the entire system. On this occasion, we also propose a general plant formation suitable to mixed $H_2/H_{\infty}$ control and $\mu$-theory. Finally, the effectiveness of the proposed design method is verified through experimentation.