• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.6
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• pp.747-752
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• 2006

In this paper, the adaptive fuzzy sliding mode controller with two systems is designed. The existing sliding mode controller used to $approximation{\^{u}}(t)$ with discrete sgn function and sat function for keeping the state trajectories on the sliding surface[1]. The proposed controller decrease the disturbance for uncertain control gain and This paper is concerned with an Adaptive Fuzzy Sliding Mode Control(AFSMC) that the fuzzy systems ate 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 ate demonstrated. Futhermore, fuzzy tuning improve tracking abilities by changing some sliding conditions. In the traditional sliding mode control, ${\eta}$ is a positive constant. The increase of ${\eta}$ has led to a significant decrease in the rise time. However, this has resulted in higher overshoot. Therefore the proposed ${\eta}$ tuning AFSMC improve the performances, so that the controller can track the trajectories faster and more exactly than ordinary controller. The simulation results demonstrate that the performance is improved and the system also exhibits stability.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.2
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• pp.157-164
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• 2016

The paper studies a comparison analysis of semi-active control strategies for a Macpherson strut type suspension system consisting of MR(magneto-rheological) damper. As a first step, in order to formulate governing, a dynamic full model of a Macpherson strut is developed considering the kinematics. The nonlinear equation of motion of the strut is then linearized around the equilibrium point. A new adaptive moving sliding model controller is developed for fast response of the system. A newly proposed adaptive moving sliding mode control strategy is then compared with conventional sliding mode controller and skyhook controller. The comparison is made for two different types of road inputs; bump and random road profiles showing superior vibration control performance in time and frequency domains.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.10
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• pp.109-117
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• 1999

In this paper, a direct adaptive control, based on Lyapunov Function Candidate, is applied to a nonlinear Gunner's Primary Stabilized Head Mirror system to derive a parameter adaptation scheme; furthemore, a nonlinear sliding mode control, but also compensating the error in identification of the parameters which are even varying of have uncertain values. The performance of the adaptive controller is determined by the tracking ability to a desired model under some disturbances and the slowly varying parameters of the system. Both adaptive scheme and sliding mode play an important fole in the improvement of the nonlinear system control.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.197-203
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• 1998

본 논문에서는 분석적인 방법을 통하여 퍼지 제어기의 안정성을 증명할 경우에 고려해야하는 근사화 에러를 슬라이딩 모드 제어 기법과 적응 제어 법칙을 이용하여 보정하는 방법을 제시하고 있다. 특히 본 논문에서는 퍼지 제어기의 안정성에 관한 이전의 연구들과는 달리 주어진 시스템의 각각의 상태 변수들에 대한 최대 민감도(Upper Bound of Sensitivity)에 관한 정보만이 미리 주어진 경우를 다루고 있다. 모의 실험은 라이프노프(Lyapunov)함수를 사용하여 안정성이 증명될 수 있으며, 모의 실험(Simulation)을 통하여 성능을 확인할 수 있다. 또한 제어기의 적용 방법에 따라서 퍼지 제어기의 특성을 강조하거나 또는 슬라이딩 모드 제어기의 특성을 보다 더 부각 시킬 수 있도록 설계할 수 있다는 장점이 있다.

• Journal of Drive and Control
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• v.15 no.3
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• pp.8-13
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• 2018

This paper presents a phase portrait analysis-based safety control algorithm for excavators, using adaptive sliding mode control. Since working postures and material types cause the excavator's rotational inertia to vary, the rotational inertia was estimated, and this estimation was used to design an adaptive sliding mode controller for collision avoidance of the excavator. In order to estimate the rotational inertia, the recursive least-squares estimation with multiple forgetting was applied with the information of the swing velocity of the excavator. For realistic evaluation, an actual working scenario-based performance evaluation was conducted. Based on the estimated rotational inertia and an analysis of estimation errors, sliding mode control inputs were computed. The actual working scenario-based performance evaluation of the designed safety algorithm was conducted, and the results showed that the developed safety control algorithm can efficiently avoid a collision with an object in consideration of rotational inertia variations.

• Journal of Advanced Navigation Technology
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• v.13 no.5
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• pp.756-762
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• 2009

As nonlinear friction, stick-slip friction in hydraulic actuators are a problem for accuracy and repeatability. Therefore friction compensation has been approached through various control algorithms. A Adaptive discrete time sliding mode tracking controller has been applied in order to compensate the nonlinear friction characteristics in a hydraulic Actuator. Based on the diophantine equation, a new discrete time sliding function is defined and utilized for the control law which includes a friction and modeling error. Robustness is increased by using both a projection algorithm and a sliding function-based nonlinear feedforward. From the results of simulation and experiment good tracking performance is achieved.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.4
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• pp.66-73
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• 2002

Although the general sliding mode control has the robust property, bounds on the disturbances and parameter variations are known to the designer of the system control. But sometimes these bounds may not be easily obtained. However, fuzzy control provides an effective way to design the controller of the system with the disturbances and parameter variations. Therefore, combination of the best feature of fuzzy control and sliding mode control is considered. When using the conventional VSC, generally the reaching phase problem occurs, which cause the system response to be sensitive to parameter variations and external disturbances. In order to overcome these problems, an adaptive fuzzy VSC with sliding surface eliminating reaching phase is proposed. The validity of the proposed scheme is shown by results of experiments for the BLDC motor.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.325-325
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• 2000

This paper proposes a modified adaptive sliding mode control which improve the performance by making the system follow the nominal trajectories controlled by nominal controller. This method is used for the system with unknown parameter uncertainty and bounded uncertainties.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.8
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• pp.42-47
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• 2006

In this paper, we propose a sliding mode control with the bound estimation for robot manipulators without requiring exact knowledge of the robot dynamics. For the bound estimation, the upper bound of the uncertain nonlinearities of robot dynamics is represented as a Fredholm integral equation of the first kind and we propose an adaptive scheme which is only dependent on the sliding surface function. Also, we prove the asymptotic stability for the robot systems using two important properties in the robot dynamics: skew-symmetry and positive-definiteness of robot parameters.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.9
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• pp.788-792
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• 2001

Although the general sliding model control has the robust property, bounds on the disturbances and parameter variations should be known a prior to the designer of the control system. However, these bounds may not be easily obtained. Fuzzy logic provides an effective way to design a controller of the system with disturbances and parameter variations. Therefore, combination of the best feature of the fuzzy logic control and the sliding mode control is considered. In this paper, the adaptive fuzzy variable structure controller developed for variables of fuzzy logic. A variable length pendulum system is used to demonstrate the availability of the proposed algorithm.