• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.134-144
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• 2017

This paper presents an adaptive control strategy for the speed control of a four-phase switched reluctance motor (SRM) in automotive applications. The main objective is to minimize the torque ripples, despite the unstructured uncertainties, time-varying parameters and external load disturbances. The bound of perturbations is not required to be known in the developing of the proposed adaptive-based control method. In order to achieve a smooth control effort, some properties are incorporated and the proposed control algorithm is constructed using the Lyapunov theorem where the closed-loop stability and robust tracking are ensured. The effectiveness of the proposed controller in rejecting high perturbed load torque with smooth control effort is verified with comparing of an adaptive sliding mode control (ASMC) and validated with experimental results.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.12
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• pp.1077-1082
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• 2005

In this paper, it is proposed that the method for constituting pressure control system controlled by Direct Drive Valve (DDV). The DDV has a pressure-feedback-loop itself. It can eliminate non-linearity and uncertainty oi hydraulic system such as uncertain discharge coefficient and change of bulk-modulus. However, the internal feedback-loop can not compensate them perfectly. And fixed gain of the DDV's internal feedback-loop is not proper to apply it through wide pressure range. The steady state error and nonlinear characteristic of transient behaviour is observed in the experiment. So another controller is needed for the desirable performance of the system. To compose the controller, the pressure control system controlled by DDV is modeled mathematically and the parameters of the model are identified using signal-compression method. Then sliding mode controller is designed based on mathematical model. Desirable performance of the pressure control system controlled by DDV is obtained.

• Structural Engineering and Mechanics
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• v.26 no.5
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• pp.483-498
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• 2007

In case of considering the shear effect, the complete solutions are obtained for dynamic plastic response of a rigid, perfectly plastic hinged-free beam, of which one end is hinged and the other end free, subjected to a transverse strike by a travelling rigid mass at an arbitrary location along its span. Special attention is paid to new deformation mechanisms due to shear sliding on both sides of the rigid mass and the plastic energy dissipation. The dimensionless numerical results demonstrate that three parameters, i.e., mass ratio, impact position of mass, as well as the non-dimensional fully plastic shear force, have significant influence on the partitioning of dissipated energy and failure mode of the hingedfree beam. The shear effect can never be negligible when the mass ratio is comparatively small and the impact location of mass is close to the hinged end.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.692-697
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• 2001

A precise tracking control scheme on the system in presence of nonlinear dynamic friction is proposed. In this control scheme, the standard SMC is combined with the nonlinear observer to estimate the dynamic friction state that is impossible to measure. Then this control scheme has the good tracking performance and the robustness to parameter variation compared with the standard SMC and the PiD based nonlinear observer control system. This fact is proved by the experiment on the ball-screw driven servo system with the dynamic friction model.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.7
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• pp.524-531
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• 2003

This paper presents an active vibration control of a flexible beam structure using a hybrid mount which consists of elastic rubber and Piezoelectric material. After identifying stiffness and damping properties of the rubber and piezoelectric elements, a mechanical model of the hybrid mount is established. The mount model is then Incorporated into the beam structure, and the governing equation of motion is obtained in a state space. A sliding mode controller is designed in order to actively attenuate the vibration of the beam structure subjected to high frequency and small magnitude excitations. The controller is experimentally realized and control responses such as acceleration of the beam structure and force transmission through the hybrid mount are evaluated. In addition. a comparative work is done between the passive and hybrid mount systems.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.439-445
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• 1990

All models of dynamical systems invariably have some measure of uncertainties associated with some of their dynamics. The recent approaches to establish robustness of stabilizing feedback control against the possible uncertainties have a serious limitation, that is their applicability only to the systems that satisfy the matching conditions. Such conditions are rarely met in general applications. If a particular system satisfies the matching conditions, the addition of an actuator will destroy the satisfaction of such conditions. In this paper, we develop robust control algorithm for uncertain multivariable systems in which the matching conditions are not necessarily met. We empoly Lyapunov's second method to derive robust stabilizing controllers which guarantee asymptotic stability against prescribed uncertainties. The derivation consists of transforming the original uncertain system to controllable canonical form and constructing a constant switching surface by designing the closed-loop characteristics as a function of the uncertainties. Numerical examples are discussed as illustrations.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1337-1338
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• 2015

In this paper, a new control technique using WIPDC(Weighted Integral Parallel Distributed Compensation) and ISMC(Integral Sliding Mode Control) is proposed for high performance and robust trajectory tracking control of a wheeled mobile robot. The WIPDC reduces the steady-state error by adding a weighted integral controller to the PDC. So, the trajectory tracking control using the WIPDC can obtain more accurate control performance than the PDC. And the ISMC based control input gives the mobile robot to preserve the system dynamics controlled by the WIPDC control input in spite of external disturbances. Therefore, the proposed control method shows a robust and precise trajectory tracking performance.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.528-530
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• 1998

This paper addresses analysis and design of a fuzzy model-based-controller for the control of uncertain SISO nonlinear systems. In the design procedure, we represent the nonlinear system by using a Takagi-Sugeno fuzzy model and construct a global fuzzy logic controller via parallel distributed compensation and sliding mode control. Unlike other parallel distributed controllers. this globally stable fuzzy controller is designed without finding a common positive definite matrix for a set of Lyapunov equations, and has good tracking performance. Furthermore, stability analysis is conducted not for the fuzzy model but for the real underlying nonlinear system. A simulation is included for the control of the Duffing forced-oscillation system, to show the effectiveness and feasibility of the proposed fuzzy control method.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.441-445
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• 1997

In this paper, we suggest a design scheme of receding horizon predictive control(RHPC) for boiler-turbine systems whose dynamics are given in nonlinear equations. RHPC is designed for linear state space models which are obtained at a nominal operating point of the boiler-turbine system. In this consideration, the boiler is operated in a sliding pressure mode, in which the reference value of drum pressure is changing according to the electrical power generation. The reference values of the system outputs are prefiltered before they are fed to the RHPC in order to compensate the linearization errors. Simulation results show that the proposed controller provides acceptable performances in both of the cases of 'steep and small changes' and 'slow and large changes' of power demand and yields the effect of modest coordination of conventional PID schemes such as boiler-following and turbine-following control.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2237-2239
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• 2001

Backstepping procedures for output-feedback of nonlinear systems are considered. For these systems, a sliding mode cascade observer to estimate derivatives of the output is builded. In the 1st step of the observer, the output is estimated, and the 1st order derivative of the output is estimated via the 2nd step of the observer. Also, n-th order derivative of the output is estimated in the n+1th step of the observer. Observer errors and tracking errors converge to a residual set close to zero asymptotically.