• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.280-285
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• 2007

This paper presents a robustly adaptive flux observer for speed-sensorless induction motor control. The proposed approach employs additional robustifying signals to cope with the parametric uncertainties instead of designing an estimator, which has been normally used in power electronic drives. For that, the sliding-mode like adaptive controls are designed and their gain parameters are determined so that the observer dynamics are stable in the sense of Lyapunov, and furthermore they can guarantee the robustness against parametric uncertainties in induction motor systems. Estimated rotor speed is to be used to generate feedback control signal for the speed sensorless vector control system. To show the validity and efficiency of the proposed system, simulation results are presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.297-300
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• 2005

This paper presents vibration control of an engine mount for a passenger vehicle utilizing ER fluid and piezoelectric actuator. The proposed engine mount can be isolated the vibration of wide frequency range with many types of amplitude. The main function of ER fluid is to attenuate vibration for low frequency with large amplitude, while the piezoelectric actuator is activated in hish frequency range with small amplitude. A mathematical model of the engine mount is derived using Hydraulic model and mechanical model. After formulating the governing equation of motion, then field-dependent dynamic stiffness of the engine mount is evaluated for various engine speed and excitation amplitude conditions. Then robust controller is designed to attenuate vibration of wide range frequency component. Computer simulation is undertaken in order to evaluate the vibration control performance such as transmissibility magnitude in frequency domains.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.4
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• pp.365-371
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• 2012

This paper presents robust control performance of a direct current(DC) motor with brake system adopting a giant electrorheological(GER) fluid, whose distinguished feature is an extremely high value of yield stress. As a first step, Bingham characteristics of the GER fluid is experimentally investigated using the Couette type electroviscometer. A cylindrical type of ER brake is then devised based on the Bingham model, and its braking torque is evaluated. Structural analysis of ER break is performed using ANSYS. After formulating the governing equation of motion for the DC motor with ER brake system, a sliding mode control algorithm, which is very robust to external disturbances and parameter uncertainties, is synthesized and experimentally realized in order to achieve desired rotational speed trajectories. The tracking responses of the control system are then evaluated and verified by presenting speed control performance.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1132_1133
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• 2009

In this paper, a observer-based PI controller will be developed for PEM fuel cell system. Nonlinear model of PEM fuel cell system is introduced to study the controller design problems. Sliding mode observer will be designed to estimate the cathode and anode pressures of PEMFC system. And a nonlinear state observer is also designed to estimate the other states such as supply manifold pressure, Oxygen pressure, Hydrogen pressure, return manifold pressure, etc. These estimated states are used to design the observer-based PI controller. The validity of the proposed controller will be verified by using computer simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.440-445
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• 2002

A hybrid mount featuring elastic rubber and piezoelectric material is devised and applied to the vibration control of a beam structure. The governing equation of the beam structure associated with the hybrid mount is derived. Subsequently, a robust sliding mode controller is designed to attenuate the vibration of the beam structure due to external excitation. The controller is then simulated and control responses such as displacement and transmitted force are evaluated in time and frequency domains.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1312-1315
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• 1996

Polishing work for a curved surface die demands simple and repetitive operations and requires much time while it also demands high precision. Therefore it is operated by skilled worker in handiwork. But workers avoid polishing work gradually because of the poor environments such as dust and noise. In order to reduce the polishing time and to alleviate the problem of shortage of skilled workers, researches for automation of polishing have been pursued in the developed countries such as Japan. In this research we develop a polishing robot with 2 degrees of freedom motion and pneumatic system, and attach it to machining center with 3 degrees of freedom to form an automatic polishing system which keeps the polishing tool vertically on the surface of die and maintains constant pneumatic pressure. The developed polishing robot is controlled by real time sliding mode control using DSP(digital signal processor). A synchronization between machining center and polishing robot is accomplished by using M code of machining center. A performance experiment for polishing work is executed by the developed polishing robot.

• Journal of Electrical Engineering and information Science
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• v.3 no.1
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• pp.94-102
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• 1998

A DSP-based robust nonlinear speed control of a permanent magnet synchronous motor(PMSM) is presented. A quasi-linearized and decoupled model including the influence of parameter variations and speed measurement error on the nonlinear speed control of a PMSM is derived. Based on this model, a boundary layer integral sliding mode controller to improve the robustness and performance of the nonlinear speed control of a PMSM is designed and compared with the conventional controller. To show the validity of the proposed control scheme, simulations and experimental works are carried out and compared with the conventional control scheme.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.3
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• pp.29-41
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• 1992

According to the recent increase of demands for multi-function and economics on hydraulic excavator, it is required that excavator should have simple operation, higher and operational efficiency, however the modeling of engine/pump system of excavator is not prescribed by the paper. So, in this paper the modeling of engine/pump system of excavator is suggested by identification method from step response and verified effectiveness of identification system by comparing with experimental results which was conducted using PID controller. To improve the problem of parameter variation and modeling error in the system, sliding mode control was introduced and new switching surface was designed. This control algorithm was applied to a hydraulic excavator by simulation, and its effectiveness was verified, and the results of variable structure system for the excavator system using a output component was compared with that of full state feedback when load disturbances and system paramenter variation exist.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.347.1-347
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• 2002

A hybrid mount featuring elastic rubber and piezoelectric material is devised and applied to the vibration control of a beam structure. The governing equation of the beam structure associated with the hybrid mount is derived. Subsequently, a robust sliding mode controller is designed to attenuate the vibration of the beam structure due to external excitation. The controller is then simulated and control responses such as displatement and transmitted force are evaluated in time and frequency domains.

• Journal of Industrial Technology
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• v.16
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• pp.231-237
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• 1996

In this paper, the nonlinear I/O characteristic of fuzzy logic controller is analyzed by using cell concept. Sources of the nonlinearity in a fuzzy logic controller include the fuzzification, the fuzzy reasoning and the defuzzification. A closed form expression for the defuzzified output is derived in case of a fuzzy logic controller with two inputs, triangular memberships, MacVicar-Whelan type linguistic rules, and direct fuzzy reasoning. As a result, it is shown that fuzzy logic controller is a nonlinear controller. Also its nonlinearity is analyzed with respect to the conventional PID control and the sliding mode control.