• Journal of Advanced Marine Engineering and Technology
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• v.30 no.2
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• pp.239-246
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• 2006

This paper describes the scheme of sliding mode control (SMC) to adopt the conventional slip frequency vector drives. The purpose of sliding mode control is to achieve an accurate, robustness of response for ac servomotor speed control. A sliding mode control design method is proposed for a speed control of an induction servomotor. The control law is composed of the variable structure component and the suppressed coefficients to suppress load disturbance and variation of external parameters. The proposed control scheme is simulated by the computer which is installed in an ideal ac servomotor. The simulation results show that the proposed design method has robustness and accuracy in the speed response by adjusting the suppressed coefficients for load disturbance and the motor mechanical parameter variation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1366-1371
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• 2006

A structural coupling method is developed for the dynamic analysis of a nonlinear structure with concentrated nonlinear hinge joints or sliding lines. Component mode synthesis method is extended to couple substructures and the nonlinear models. In order to verify the improved coupling method, a numerical plate model consisting of two substructures and torsional springs, is synthesized by using the proposed method and its model parameters are compared with analysis data. Then the coupling method is applied to a three-substructure-model with the nonlinearity of sliding lines between the substructures. The coupled structural model is verified from its dynamic analysis. The analysis results show that the improved coupling method is adequate for the structural nonlinear analyses with the nonlinear hinge and sliding mode condition.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.605-609
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• 1996

Continuous sliding mode control is applied to turning process for cutting force regulation. The highest feedrate compatible with the allowable cutting force is applied in rough cutting process such that maximum productivity is ensured and tool breakage is avoided. The programmed feedrate is overridden after the control algorithm is carried out. However, most CNC lathe manufacturers offer limited number of data bits far feedrate override, thus resulting in nonlinear behavior of the machine tools. Such nonlinearity brings “quantized” effect, and the optimal faedrate is rounded off before being fed into the CNC system. To compensate for this problem, continuous sliding mode control is applied. Conventional switching control law at a sliding surface is replaced by a smooth control interpolation in a selected boundary layer to avoid the excitation of high-frequency dynamics. Simulation results are presented in comparison with those obtained by applying adaptive control.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.488-492
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• 2004

In this paper, the design of a speed sensorless vector control system for induction motor is performed by using a new sliding mode technique based on current model flux observer. A current and flux observer based on the current estimation error is constructed. The proposed current observer includes a sliding mode function, which is derivative of the flux. That is, sliding mode observer which allows the estimation of both the rotor speed and flux based on the measurement of motor terminal quantities, would be proposed. And, a synergetic speed controller using the estimated speed signal is designed to stabilize the speed loop. Simulation results are presented to confirm the theoretical analysis, and to show the system performance with different observer gains and the influence of the motor parameter.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1850-1851
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• 2006

The sliding mode control is acceptable for Autonomous Underwater Vehicle(AUV), since the dynamics of AUV are highly nonlinear and have several parameter uncertainty such as the added mass terms, the hydrodynamic coefficients. The sliding mode control can deal well with nonlinearity of the system and offers a robustness to controller with parameter uncertainty. Since sliding mode control has the defect of chattering problem, only in ideal case the actuator can respond by control law. Therefore we propose the sliding mode control with non-chattering. And computer simulations illustrate the performance of the proposed controller.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.8 s.251
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• pp.880-888
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• 2006

This paper presents the sliding mode control with the perturbation estimator for a nonlinear control system in the presence of perturbations including external disturbances, unpredictable parameter variations, ana unstructured dynamics. The proposed perturbation estimator is based on the Recursive Linear Smoothed Newton predictive algorithm so that it is effective to attenuate an undesired noise in high frequency band and to predict the present perturbation signal from the previous ones. Compared to conventional sliding mode control (SMC) and sliding mode control with perturbation estimation (SMCPE) introduced by Elmali and Olgac, the control algorithm proposed in this study can offer better tracking control performances and more feasible estimation characteristics. The effectiveness and superiority of the proposed control strategy are demonstrated by a series of simulations on the position tracking control of a simple two-link robot manipulator subject to velocity feedback signals including white noises.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.3
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• pp.67-73
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• 2002

This paper presents a sliding mode observer and Controller far the state estimation and the dynamic stabilization of the magnetic levitation systems. The proposed striding mode observer is constructed by means of Lyapunov stability theorem to decrease the observer error, and the sliding rode controller is designed by a linear combination of the equivalent and nonlinear control input for the estimated states. The feasibilities of the suggested design method are illustrated with the simulation results.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.5
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• pp.114-122
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• 2006

This paper presents a new control scheme that combines a sliding mode control and a neural network. In the proposed sliding mode control, a continuous control is employed removing the switching phenomena and the equivalent control within the boundary layer is estimated through on-line teaming of the neural network. The performances of the proposed control are compared with off-line neural network and on-line neural sliding mode control by computer simulation. The simulation results show that the proposed control reduces high frequency chattering and tracking error in example of the two link manipulator.

• Journal of Ocean Engineering and Technology
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• v.20 no.6 s.73
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• pp.7-17
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• 2006

Depth and heading control of an AUV are considered to follow the predetermined depth and heading angle. The proposed control algorithm is designed. based on a sliding mode control using estimated hydrodynamic coefficients. The hydrodynamic coefficients are estimated with conventional nonlinear observer techniques, such as sliding mode observer and extended Kalman filter. By using the estimated coefficients, a sliding mode controller is constructed for the combined diving and steering maneuver. The simulation results of the proposed control system are compared with those of control system with true coefficients. This paper demonstrates the proposed control system, discusses the mechanisms that make the system stable and follows the desired depth and heading angle, accurately, in the presence of parameter uncertainty.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.1
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• pp.30-36
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• 2004

An iterative sliding mode observer is proposed to sensorless control of a PMSM(Permanent Magnet Synchronous Motor). The proposed sliding mode observer has the character which is robust to the disturbance and parameters variation. A low pass filter with the variable cut-off frequency is also proposed to compensate the delay of the rotor angle according to the rotor speed, it is led to save memory and minimize operation time. Experimental results show that the proposed sliding mode observer leads to the proper performance.