• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.778-783
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• 2003

The problem considered in this paper is about the collocation of sensor and actuator for the active control of sound and vibration. It is well-known that a point collocated sensor-actuator pair offers an unconditional stability with very high performance when it is used with a direct velocity feedback (DVFB) control, because the pair has strictly positive real (SPR) property. In order to utilize this SPR characteristics, a matched piezoelectric sensor and actuator pair is considered, but this pair suffers from the in-plane motion coupling problem with the out-of$.$plane motion due to the piezo sensor and actuator interaction. This coupling phnomenon limits the stability and performance of the matched pair with DVFB control. As a new alternative, a point sensor and piezoelectric actuator pair is also considered, which provides SPR property in all frequency range except at the first resonance in very low frequency. This non-SPR resonance could be minimized by applying a phase lag compensator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.944-949
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• 2003

This paper addresses the control of free and dynamic response of composite rotating pretwisted blade modeled as non-uniform thin-walled beam fixed at the certain presetting and pretwisted angle and incorporating piezoelectric induced damping capabilities. A distributed piezoelectric actuator pair is used to suppress the vibrations caused by external disturbances. The blade model incorporates non-uniform features such as transverse shear, secondary warping and includes the centrifugal and Coriolis force field. A velocity feedback control law relating the piezoelectiriccally induced transversal bending moment at the beam tip with the appropriately selected kinematical response quantity is used and the beneficial effects upon the closed loop eigenvibration and dynamic characteristics of the blade are highlighted.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2002년도 추계학술대회 및 정기총회
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• pp.113-117
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• 2002

PID controllers, which have been widely used in industry, have a simple structure and robustness to modeling error. But it is difficult to have uniformly good control performance in system parameters variation or different velocity command. In this paper, we propose a nonlinear adaptive PR controller based on an Immune feedback mechanism and a gradient descent teaming. This algorithm has a simple structure and robustness to system parameters variation. To verify performances of the proposed nonlinear adaptive PID controller, the speed control of nonlinear DC motor Is peformed. The simulation results show that the proposed control systems are effective in tracking a command velocity under system parameters variation

• 전기학회논문지
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• 제65권8호
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• pp.1400-1406
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• 2016

This paper presents a new adaptive converter control approach for electric motor systems whose voltage source is excited from photovoltaic (PV) power generators. First, an electric model is represented with dynamic states and output velocity of such DC motor systems. We propose a hybrid converter control law in which a state feedback control is applied as an auxiliary control framework. Moreover, control parameter estimation is derived to realize adaptive converter systems for effective control performance against stochastic PV power excitation in practice. We carry out stability analysis for such converter system by using a well-known eigenvalue theory. Lastly, numerical simulation is conducted to test reliability of the proposed converter control approach and prove its superiority in the control point of view.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1157-1161
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• 2003

A novel actuator with built-in the displacement and the thrust control function is presented in this paper. This actuator is a kind of compact hydraulic cylinder system which consists of a hydraulic cylinder, a spool, a sleeve, a mechanical feedback mechanism and a stepping motor. The displacement and thrust is in proportion to the rotational angle of stepping motor by the mechanical feedback. In order to investigate characteristics of this actuator, simulation study and preliminary experiments are conducted. Through the preliminary experiment this actuator is very effective in the control for displacement and thrust. Also, it became obvious that the stability of system can be adjusted by using the restrictor with the effect of velocity feedback. Furthermore, this paper explained that a flexible compliance control could be realized by adjusting the feedback weighting in the actuator.

• International Journal of Aeronautical and Space Sciences
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• 제12권2호
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• pp.179-189
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• 2011

In this paper, robust adaptive control design problem is addressed for a class of parametrically uncertain aeroelastic systems. A full-state robust adaptive controller was designed to suppress aeroelastic vibrations of a nonlinear wing section. The design used leading and trailing edge control actuations. The full state feedback (FSFB) control yielded a global uniformly ultimately bounded result for two-axis vibration suppression. The pitching and plunging displacements were measurable; however, the pitching and plunging rates were not measurable. Thus, a high gain observer was used to modify the FSFB control design to become an output feedback (OFB) design while the stability analysis for the OFB control law was presented. Simulation results demonstrate the efficacy of the multi-input multi-output control toward suppressing aeroelastic vibrations and limit cycle oscillations occurring in pre- and post-flutter velocity regimes.

• 한국통신학회논문지
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• 제17권4호
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• pp.361-370
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• 1992

수직 이착륙기와 같은 비행체의 정지비행 도중 비행체의 위치각, 각속도, 각가속도와 같은 상태량을 궤환 시킨 SRFIMF(State Rate Feedback Implicit Model-Following)이론을 이용하여 4개의 팬을 갖는 부상제어시스템을 구성하였다. 이 부상제어시스템의 yaw제어를 행하여, 각 상태궤환이득 및 전향경로 이득을 변화시켜 부상제어시스템의 특정을 해석하였으며, 부상시스템과 같은 제어계에 SRFIMF방식을 적용시켜 그 타당성을 조사하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권3호
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• pp.112-121
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• 2002

This paper describes a new bike system for the postural balance rehabilitation training. Virtual environment and three dimensional graphic model is designed with CAD tools such as 3D Studio Max and World Up. For the real time bike simulation, the optimized WorldToolKit graphic library is embedded with the dynamic geometry generation method, multi-thread method, and portal generation method. In this experiment, 20 normal adults were tested to investigate the influencing factors of balancing posture. We evaluated the system by measuring the parameters such as path deviation, driving velocity, COP(center for pressure), and average weight shift. Also, we investigated the usefulness of visual feedback information by weight shift. The results showed that continuous visual feedback by weight shift was more effective than no visual feedback in the postural balance control It is concluded this system might be applied to clinical use as a new postural balance training system.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권6호
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• pp.342-350
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• 2003

In this paper, a levitation controller for a magnetic levitation(MagLev) system is designed and implemented. The target to be controlled is PEM(permanent and electromagnet) type with 4-corners levitation which is open-loop unstable, highly non-linear and time-varying system. The digital control system consists of a VME-based CPU board, AD board, PU board, 4-Quadrant chopper, and gap sensor, accelerometer as feedback sensors. In order to estimate the velocity of the magnet, we used 2nd-order state observer with acceleration and gap signal as input and output, respectively. Using the estimated states, a state feedback control law for the plant is designed and the feedback gains are selected by using the pole-placement method. The designed controller is experimentally validated by step-type gap reference change and force disturbance test.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.469-474
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• 2000

A sliding mode control method using the parameterization of both the hyperplane and the compensator for output feedback and reduced observer is presented for rotational inverted pendulums. This control strategy overcomes the problem of unattainable velocity state which is resulted from severe noise of analogue sense and constructs numerical algorithms designs of dynamic output feedback sliding mode hyperplane and controller. The result of the experiment shows the superior performance compared with the LQ controller and the robustness with respect to both tapping disturbances and certain initial conditions.