• Journal of Institute of Control, Robotics and Systems
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• v.22 no.6
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• pp.417-423
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• 2016

Using a sliding mode controller and observer techniques, this paper presents a robust current controller for a DC motor in the presence of parametric uncertainties. One of the most important issues in the practical application of sliding mode schemes is the chattering phenomenon caused by switching actions. This paper presents a novel sliding mode controller that incorporates an integral control with a sliding mode disturbance observer to attenuate the chattering by reducing the controller/observer switching gains. The proposed sliding mode disturbance observer is designed to estimate a relatively slow varying signal in the equivalent lumped disturbance owing to system uncertainties. Combining the estimated uncertainty with the sliding mode control input, the proposed controller can achieve the control objective by using the relatively low gain of the controller. The proposed disturbance observer does not include the switching control input of the baseline sliding mode controller to reduce the observer switching gain. In the proposed approach, the integral sliding mode control is used to improve the steady state control performance. Comparative computer simulations are carried out to demonstrate the performance of the proposed method. Through the simulation results, the proposed controller realizes the robust performance with reduced current ripples.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.221-224
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• 2000

We consider one of robust controller, fuzzy-sliding mode controller dealing with model uncertainty, simplified representation of nonlinear system, changed parameters of plant. We propose fuzzy-sliding mode algorithm which provides control input that has system states approaching the choosed sliding surface. This fuzzy controller has a rule base to get initial states converged on sliding surface. This algorithm Is applied to a transfer function of DC motor to be modeled simply and do position control of DC motor due to system parameters. We compare fuzzy-sliding mode controller to both sliding mode controller and fuzzy controller to identify roust control.

• Smart Structures and Systems
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• v.5 no.3
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• pp.261-277
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• 2009

A fuzzy-sliding mode controller is presented to control the dynamics of semi-active suspension systems of vehicles using magneto-rheological (MR) fluid dampers. A full car model is used to design and evaluate the performance of the proposed semi-active controlled suspension system. Four mixed mode MR dampers are designed, manufactured, and integrated with four independent sliding mode controllers. The siding mode controller is designed to decrease the energy consumption and maintain robustness. In order to overcome the chattering of the sliding mode controllers, a fuzzy logic control strategy is merged into the sliding mode controller. The proposed fuzzy-sliding mode controller is designed and fabricated. The performance of the semi-active suspensions is evaluated in both the time and frequency domains. The obtained results demonstrate that the proposed fuzzy-sliding mode controller can effectively suppress the vibration of vehicles and improve their ride comfort and handling stability. Furthermore, it is shown that the "chattering" of the sliding mode controller is smoothed when it is integrated with a fuzzy logic control strategy. Although the cost function of the fuzzy-sliding mode control is a slightly higher than that of a classical LQR controller, the control effectiveness and robustness are enhanced considerably.

• Journal of Mechanical Science and Technology
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• v.19 no.10
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• pp.1846-1855
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• 2005

This paper presents a new stochastic controller applied on the vibration control system under irregular disturbances based on the mode selection scheme. Measured displacement and frequency characteristics are simultaneously used in designing a mode selecting controller. This technique is validated by applying to the suppression problem of a flexible beam with randomly vibrated circumstances. The presented method, called Mode Selecting Stochastic Controller, uses the frequency measurement of the flexible system based on a Fast-Fourier transformation algorithm. This controller is constructed by combining mode selection method with previous known Stochastic Controller in real time: Numerical simulations and several experiments are conducted to validate the proposed method. The performance of the proposed method is compared with a stochastic controller developed recently. This method was improved compared with previous one.

• Journal of Power Electronics
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• v.10 no.1
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• pp.21-26
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• 2010

The most important feature of the one-cycle control method is its excellent ability in line disturbance rejection. However, when it is used as a controller in dc-dc converters, it has an undesirable transient response. The voltage overshoot at the transient time, which usually exists in one-cycle controlled converters, is unwanted in many applications and it is sometimes hazardous. In this paper, it is shown that the combination of a one-cycle controller with a current mode controller, can improve the transient response and consequently the overshoot can be controlled. Therefore, the combined controller has the excellent line disturbance rejection of a one-cycle controller and the output current limiting capability of current mode controllers. Because in this scheme a one-cycle controller is the master controller, the problem of instability of current mode control, will not happen. By simulation and a practical prototype, the capability of the method is shown.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.722-726
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• 2007

In this paper we deal with a design of the integral sliding mode controller to suppress the disturbance force acting on the suspension system of the magnetically levitated train system. One of the important factors that cause the disturbance force acting on the suspension system comes from the low propulsion speed of linear induction motor. In this paper integral sliding mode controller is employed to reject the disturbance force produced by the propulsion system of the linear induction motor. In order to show the effectiveness of the designed controller a dynamic simulation is utilized and the sliding mode controller without integral compensator is compared with the proposed integral sliding mode controller to suppress the disturbance force.

• Journal of Institute of Control, Robotics and Systems
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• v.1 no.1
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• pp.25-32
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• 1995

Nonlinear depth control algorithms for the hovering system of underwater vehicles are presented. In this paper, a nonlinear effect in heave motion for underwater vehicles, a deadzone effect of the flow control valve in the hovering tank and an impact disturbance are considered. In this situation, in order to choose a desirable controller, sliding mode controller and fuzzy sliding mode controller are designed and compared. The computer simulation results show that the fuzzy sliding mode control system is more suitable in order to maintain a desirable depth of an underwater vehicle with a deadzone and impact disturbance.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.111-116
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• 1998

This paper proposes a robust control using a sliding mode controller and a fuzzy controller. Having the excellent transient response, the sliding mode controller has the poor steady state response, but the fuzzy controller has a good steady state reponse. A proposed controller combined these controllers has the quick response at the initial condition without the errors. The proposed robust nonlinear controller takes the advantage of the fuzzy controller and is the rapid and the stable response in conditions that the sliding mode controller keeps the errors at the steady state. The performance of proposed method is proved by simulation of the inverted pendulum.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.2
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• pp.89-96
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• 2002

A new chattering free PD-sliding mode hybrid control scheme is proposed for robot manipulators. This hybrid controller is composed of a PD controller and a semi-continuous sliding mode controller. It has a good robust performance in reaching mode which does not possess invariance property of sliding mode, and has chattering free characteristics in sliding mode. Thus, the PD-sliding mode hybrid controller has a good robust performance in the whole region. It is shown that the proposed control has a good transient response and trajectory tracking performance for a 2-link SCARA robot manipulator.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.29-32
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• 1989

This paper proposes new position control method for DC servo motor by PI controller adopting sliding mode control. By adding sliding mode controller to conventional PI controller good robustness is obtained with good transient response and no steady state error which are merits in PI controller. In order to use microprocessor for digital control the principles of sliding mode control conventionally explained in continous-time system are extended to discrete-time system.