• 대한기계학회논문집A
• /
• 제20권11호
• /
• pp.3560-3572
• /
• 1996

This paper presents a new discrete-time fuzzy-sliding mode controller for robust vibration control of a smart structure featuring a piezofilm actuator. A governong equation of motion for the smart beam structure is derived and discrete-time codel with mismatched uncertainties such as parameter variations is constructed ina state space. A discrete-time sliding mode control system consisting of an equivalent controller and a discontinuous controller is formulated. In the design of the equivalent part, so called an equivalent controller separation method is adopted to achieve vzster convergence to a sliding surface without extension of a sliding region, in which the system robustness maynot be guaranteed. On the other hand, the discontinuous part is constructed on the basis of both the sliding and the convergence conditions using a time-varying feedback gain. The sliding moide controller is then incorporated with a fuzzy technique to appropriately determine principal control parameters such as a discountinuous feedback gain. Experimental implementation on the forced and random vibraiton controls is undertaken in order to demonstrate superior control performance of the proposed controller.

• 한국전자통신학회논문지
• /
• 제2권2호
• /
• pp.67-74
• /
• 2007

채터링 현상은 VSS의 주요한 약점이며 이 문제를 극복하기위하여 많은 연구들이 발표되었다. 슬라이딩 섹터 이론이 최근에 발표되었으며, 섹터 안에서 제어입력 없이 상태의 놈이 감소하고 상태가 섹터 안에 있는 동안에 상태의 놈은 영으로 수렴한다. 슬라이딩 섹터 이론은 기본적인 연구단계에 있으며 선형시스템에 대하여 연구되어있다. 본 논문에서는 슬라이딩 섹터를 이용하여 불안정한 비선형시스템의 추적제어하는 새로운 방식을 제안하며 슬라이딩 섹터에 리아프노프 함수를 이용하여 안정도를 분석한다. 역진자 시스템에 컴퓨터 시뮬레이션을 통하여 제안한 슬라이딩 섹터 제어가 채터링을 줄일 수 있는 것을 확인한다.

• Journal of Electrical Engineering and Technology
• /
• 제13권3호
• /
• pp.1185-1201
• /
• 2018

This paper presents a sensorless direct torque control (DTC) combined with sliding mode approach (SM) and space vector modulation (SVM) to achieve mainly a high performance and reduce torque and flux ripples of a parallel-connected two five-phase permanent magnet synchronous machine (PMSM) drive system. In order to increase the proposed drive robustness and decrease its complexity and cost, the rotor speeds, rotor positions, fluxes as well as torques are estimated by using a sliding mode observer (SMO) scheme. The effectiveness of the proposed sliding mode observer in conjunction with the sliding mode control based DTC is confirmed through the application of different load torques for wide speed range operation. Comparison between sliding mode control and proportional integral (PI) control based DTC of the proposed two-motor drive is provided. The obtained speeds, torques and fluxes responses follow their references; even in low and reverse speed operations, load torques changes, and machines parameters variations. Simulation results confirm also that, the ripples of the torques and fluxes are reduced more than 3.33% and 16.66 %, respectively, and the speed overshoots and speed drops are reduced about 99.85% and 92.24%, respectively.

• Journal of Power Electronics
• /
• 제14권5호
• /
• pp.980-988
• /
• 2014

This paper proposes an online gain tuning algorithm for a robust sliding mode speed controller of surface-mounted permanent magnet synchronous motor (SPMSM) drives. The proposed controller is constructed by a fuzzy neural network control (FNNC) term and a sliding mode control (SMC) term. Based on a fuzzy neural network, the first term is designed to approximate the nonlinear factors while the second term is used to stabilize the system dynamics by employing an online tuning rule. Therefore, unlike conventional speed controllers, the proposed control scheme does not require any knowledge of the system parameters. As a result, it is very robust to system parameter variations. The stability evaluation of the proposed control system is fully described based on the Lyapunov theory and related lemmas. For comparison purposes, a conventional sliding mode control (SMC) scheme is also tested under the same conditions as the proposed control method. It can be seen from the experimental results that the proposed SMC scheme exhibits better control performance (i.e., faster and more robust dynamic behavior, and a smaller steady-state error) than the conventional SMC method.

• Journal of Mechanical Science and Technology
• /
• 제15권3호
• /
• pp.339-350
• /
• 2001

To overcome problems in tracking error related to the unmodeled dynamics in the high speed operation of industrial robots, many researchers have used sliding mode control, which is robust against parameter variations and payload changes. However, these algorithms cannot reduce the inherent chattering which is caused by excessive switching inputs around the sliding surface. This study proposes a fuzzy-sliding mode control algorithm to reduce the chattering of the sliding mode control by fuzzy rules within a pre-determined dead zone. Trajectory tracking simulations and experiments show that chattering can be reduced prominently by the fuzzy-sliding mode control algorithm compared to a sliding mode control with two dead zones, and the proposed control algorithm is robust to changes in payload. The proposed control algorithm is implemented to the SCARA (selected compliance articulated robot assembly) robot using a DSP (digital signal processor) for high speed calculations.

• 한국안전학회지
• /
• 제35권1호
• /
• pp.53-61
• /
• 2020

This study proposes a new damper configuration for seismic performance improvement of heavy sliding facilities inside a building. For this purpose, we deal with two connection types of control system, and the parametric study has been performed to investigate their comparative seismic performances according to the variations of the control capacity. In order to simulate the seismic responses of the proposed system, we employed a recently-developed seismic response analysis method that can deal with the two-mass system with nonlinear frictional sliding behavior. The numerical results demonstrate that the typical method of diagonal bracing damper connection can exhibit effective control performance both on structure and the heavy sliding facilities, whereas the structure-facilities connection method does not show any control effect on both responses. On the other hand, the typical method has some limitations that it can adversely cause excessive sliding of the facilities, depending upon the frequency characteristics of structure and earthquake. On the contrary, the structure-facilities connection method is very effective in reducing the sliding displacement of the heavy facilities, even with small amount of control capacity. Thus, the following potential expectations can be inferred from these results: The typical diagonal bracing damper connection method will have some promising benefits in controlling the sliding facilities inside the building as well as the building itself, and the structure-facilities connection method can be a cost-effective way of protecting the internal heavy important facilities inside the structure already designed with sufficient seismic performance.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2005년도 ICCAS
• /
• pp.1516-1520
• /
• 2005

We proposed the indirect adaptive fuzzy model based sliding mode controller to control a nonaffine nonlinear systems. Takagi-Sugano fuzzy system is used to represent the nonaffine nonlinear system and then inverted to design the controller at each sampling time. Also sliding mode component is employed to eliminate the effects of disturbances, while a fuzzy model component equipped with an adaptation mechanism reduces modeling uncertainties by approximating model uncertainties. The proposed controller and adaptive laws guarantee that the closed-loop system is stable in the sense of Lyapunov and the output tracks a desired trajectory asymptotically.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2011년도 추계 학술논문 발표대회
• /
• pp.131-132
• /
• 2011

Non-working days owing to climatic factors have been negatively affected in productivity of construction, such as delays of project completion times, decrease productivity of construction. Especially non-working days of steel erection work is about 58 days, it is influenced deleteriously to estimating uncertain construction duration. To solve this problem, Construction Factory(CF) and sliding roof system installed CF's upper side are developed in korea recently. This study is proposed the design of sliding roof system through assess relation of requirements and technical characteristics using Quality Function Deployment(QFD). The basis data for applying QFD is collected from literature reviews and questionnaires/interviews targeting system developer, experts and researchers.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제5권2호
• /
• pp.145-150
• /
• 2005

We proposed the indirect adaptive fuzzy model based sliding mode controller to control nonaffine nonlinear systems. Takagi-Sugano fuzzy system is used to represent the nonaffine nonlinear system and then inverted to design the controller at each sampling time. Also sliding mode component is employed to eliminate the effects of disturbances, while a fuzzy model component equipped with an adaptation mechanism reduces modeling uncertainties by approximating model uncertainties. The proposed controller and adaptive laws guarantee that the closed-loop system is stable in the sense of Lyapunov and the output tracks a desired trajectory asymptotically.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2005년도 전력전자학술대회 논문집
• /
• pp.697-700
• /
• 2005

An adaptive fuzzy sliding-mode controller (SMC) for uncertain or ill-defined single-input single-output (SISO) nonaffine nonlinear systems is proposed. By using the universal approximation property of the fuzzy logic system (FLS), it is tuned on-line to cancel the unknown system nonlinearity. We adopt a self-structuring FLS to guarantee global stability of the closed-loop system rather than semi=global boundedness. The control and adaptive laws are derived so that the estimated fuzzy parameters are bounded and the sliding condition is satisfied.