• Journal of the Institute of Electronics Engineers of Korea SC
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• v.38 no.6
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• pp.37-47
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• 2001

Due to the friction characteristics of pump, cylinder packing and passenger car, in the elevator actuated with hydraulic inverter-fed systems, there exist dead zones, which cannot be controlled by a PID controller. To overcome the drawbacks, in this paper, we propose a new hybrid control scheme, which switches the modes between a sliding mode controller and a PID controller. The proposed hybrid control scheme achieves an improved control performance by using both controllers. We first propose a design method of sliding mode controller for a hydraulic elevator system controlled by inverters, then fellowed by a design method of a hybrid sliding mode control scheme is proposed. The effectiveness of the proposed control scheme are shown by simulation results, which the proposed hybrid control method yields better control performance then the PID controlled scheme, not only in the zero-crossing speed region but also in the overall control region including steady-state region.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.2
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• pp.71-80
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• 2002

According to the rapid growth of high speed and precise industry, the application of synchronous motor has been increased. In the application fields, these fast dynamic response is of prime importance. In particular, since the PMLSM(Permanent Magnet Linear Synchronous Motor) has characteristics of high speed, high thrust, it has been used in high-performance servo drive. From these reasons, it is recently used for high precise position control, and machine tool. In this paper, a study of the sliding mode with VSS (Variable Structure System) design for a PMLSM is presented. For fast and precise motion control of PMLSM, the compensation of disturbance and parameter variation is necessary. Hence we eliminate the reaching phase use of VSS that is changed to switching function and vector control using the state observer. And we proposed to sliding mode control algorithm so that realize fast response without overshoot, disturbance and parameter variation.

• Tribology and Lubricants
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• v.20 no.1
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• pp.7-13
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• 2004

High strength steels are widely used as tribo-materials in the field. Previous study revealed that for mild steel, the states of strain on the worn surface measured by X-ray diffraction has a good relationship with the state of wear. The objective of this study is to identify the relationship between the state of strain on the worn surface and the state of wear in high strength steels. Sliding wear tests were carried out using several hardened steels. X-ray diffraction tests were conducted to analyze the state of strain on the worn surface during wear. The experimental results indicated that the state of strain on worn surface in the hardened steel shows the same tendency as in the mild steel. It is clear that change of half value width on the worn surface as a function of sliding speeds is broadly similar in shape to wear characteristics curve and its magnitude has a good relationship with the wear rate at two different wear modes in the hardened steel.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.182-182
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• 2000

This paper proposes a self tuning fuzzy inference method by the genetic algorithm in the fuzzy-sliding mode control for a robot. Using this method, the number of inference rules and the shape of membership functions are optimized without an expert in robotics. The fuzzy outputs of the consequent part are updated by the gradient descent method. And, it is guaranteed that the selected solution become the global optimal solution by optimizing the Akaike's information criterion. The trajectory trucking experiment of the polishing robot system shows that the optimal fuzzy inference rules are automatically selected by the genetic algorithm and the proposed fuzzy-sliding model controller provides reliable tracking performance during the polishing process.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2236-2238
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• 2004

This paper proposes the self-recurrent wavelet neural network (SRWNN) observer based sliding mode control (SMC) method for nonlinear systems. Unlike the classical SMC, we assume that all states of nonlinear systems are not measured and design the SRWNN observer to measure the states of nonlinear systems. The SRWNN in the observer is used for approximating the observer system's gain. To generate the control input for controlling the nonlinear system, the measured states are used. The sliding surface with a boundary layer is defined to remove the chattering of the control input. Simulation result to show the effectiveness of the SRWNN observer is presented.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2191-2193
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• 2004

The Sliding Mode Control is more robust and give the better performance than the $H_{\infty}$ control if the matching condition is satisfied. So in this paper, a controller which can have the advantages of $H_{\infty}$ control and the SMC is proposed to add the robustness of the SMC to the $H_{\infty}$ controller. The dynamic of proposed sliding surface is the same dynamic as the system controlled by $H_{\infty}$ controller without the uncertainties which satisfy the matching condition.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.4
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• pp.27-34
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• 1989

An adaptive model following controller is designed using the theory of variable structure systems. The proposed method based on the modified condition for the sliding mode allows the designer to satisfy the requirements to speed up the reaching phase and for the magnitude of the chattering to be reduced in the sliding mode. Chattering reduction is obtained by the replacement of control input in the neighborhood of the sliding plane. The results of computer simulation show that state trajectories reach switching plane fast and chattering is reduced.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.151-157
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• 2004

In this paper, we propose a simple control scheme, based on second order sliding modes, which guarantees a fast and precise container transfer and the swing suppression during the container movement, despite of model uncertainties and unmodeled dynamic actuators. In the actual case, the swing suppression is obtained by constraining the system motion on a suitable surface which involves both the desired path and the swing angle. Strictly speaking, the trolley velocity is modified on-line, on the actual swing angle, to obtain the suppression of the oscillations not only at the end of the transport but during transfer as well. Such controller has been tested on a laboratory-size model of the 3Dcrane, and some experimental results are reported.

• Journal of Power Electronics
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• v.13 no.3
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• pp.381-389
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• 2013

A method to control the speed or the torque of a permanent-magnet direct current motor is presented. The rotor speed and the external torque estimation are simultaneously provided by appropriate observers. The sensorless control scheme is based on current measurement and switching states of power devices. The observers performances are dependent on the accurate machine parameters knowledge. Sliding mode control approach was adopted for drive control, providing the suitable switching states to the chopper power devices. Despite the predictable chattering, a convenient first order switching function was considered enough to define the sliding surface and to correspond with the desired control specifications and drive performance. The experimental implementation was supported on a single dsPIC and the controller includes a logic overcurrent protection.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.226-228
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• 2006

This paper is concerned with an Adaptive Fuzzy Sliding Mode Control(AFSMC) that the fuzzy systems are used to approximate the unknown functions of nonlinear system. In the adaptive fuzzy system, we adopt the adaptive law to approximate the dynamics of the nonlinear plant and to adjust the parameters of AFSMC. The stability of the suggested control system is proved via Lyapunov stability theorem, and convergence and robustness properties are demonstrated. The simulation results demonstrate that the performance is improved and the system also exhibits stability.