• 전기학회논문지P
• /
• 제54권3호
• /
• pp.119-128
• /
• 2005

In this paper, an robust adaptive backstepping controller is proposed for the chaos system with disturbances. This controller will be applicable to the chaos system of strict-feedback form and utilize the saturation function for decreasing the effect of disturbances derived from unmodelled dynamics and external noise. It shows that backstepping algorithm can be used to solve the problems of nonlinear system very well and robust controller can be designed without the variation of adaptive law. Simulation results are provided to demonstrate the effectiveness of the proposed controller.

• Journal of Electrical Engineering and Technology
• /
• 제2권4호
• /
• pp.478-484
• /
• 2007

This paper deals with the high efficient vector control for the reduction of copper losses of the doubly fed motor. Firstly, the feedback linearization control based on Lyapunov approach is employed to design the underlying controller achieving the double fluxes orientation. The fluxes# controllers are designed independently of the speed. The speed controller is designed using the Lyapunov method especially employed to the unknown load torques. The global asymptotic stability of the overall system is theoretically proven. Secondly, a new Torque Copper Losses Factor is proposed to deal with the problem of the machine copper losses. Its main function is to optimize the torque in keeping the machine saturation at an acceptable level. This leads to a reduction in machine currents and therefore their accompanied copper losses guaranteeing improved machine efficiency. The simulation and experimental results in comparative presentation confirm largely the effectiveness of the proposed DFIM control with a very interesting energy saving contribution.

• 한국전산구조공학회논문집
• /
• 제17권4호
• /
• pp.343-350
• /
• 2004

본 논문은 에너지소산 제어알고리듬의 제어이득 산정에 관하여 연구하였다. Lyapunov안정성이론에 기초하여 속도 되먹임 포화제어알고리듬, 뱅뱅제어 알고리듬 그리고 에너지게인 제어알고리듬을 제안하였고, 이 알고리듬의 성능을 평가하고 비교하였다. 속도 되먹임 포화제어알고리듬과 에너지게인 제어알고리듬에서는 포화현상을 고려하였고, 뱅뱅제어에서는 경계층을 이용하여 채터링현상을 고려하였다. 수치적인 해석을 통해서 제안된 제어알고리듬이 바람하중에 의해 야기되어지는 구조물의 에너지를 효과적으로 소산시킬 수 있음을 보여주었다.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
• /
• 제5권1호
• /
• pp.46-52
• /
• 2002

A robust nonlinear observer, utilizing the sliding mode concept, is developed for the dynamic positioning of ships. The observer provides the estimates of linear velocities of the ship and bias from slowly varying environmental loads. It also filters out wave frequency motion to avoid wear of actuators and excessive fuel consumption. The main advantage of the proposed observer is in its robustness. Especially, the observer structure with a saturation function makes the proposed observer robust against neglected nonlinearties, disturbances and uncertainties. Since the mathematical model of DP ships is difficult to obtain and includes uncertainties and disturbances, it is very important for the observer to be robust. A nonlinear output feedback controller is derives based on the developed observer using the observer backstepping technique, and the global stability of the observer and control law is shown by Lyapunov stability theory.. A set of simulation was carried out to investigate the performance of the proposed observer for dynamic positioning of ships.

• Physical Therapy Rehabilitation Science
• /
• 제10권4호
• /
• pp.421-429
• /
• 2021

Objective: The purpose of this study was to examine the effect of personalized complex aerobic training programs using wearable device on cardiovascular and respiratory functions in community based female elderly. Design: One group pre-post intervention study. Methods: Twenty-one older female participants lived in 'D' city were included. The personalized complex aerobic training program using wearable devices was applied to all participants for 4 weeks, 3 times a week, 30 minutes for per session. The participants' blood pressure, heart rate, oxygen saturation, respiration rate, submaximal exercise stress test, pulmonary function test and respiratory muscle strength test were evaluated before and after the complex training program. Results: After intervention, resting diastolic blood pressure, resting systolic blood pressure and the systolic blood pressure after submaximal exercise stress test were significantly decreased over time (p<0.05), and the submaximal exercise stress test duration were significantly increased over time (p<0.05). The maximal inspiratory pressure (MIP) was significantly increased compare to before the intervention (p<0.05). Conclusions: This study showed that personalized complex training program using wearable device can provide personalized exercise intensity according to cardiopulmonary function that give feedback, and these interventions have a significant effect on improving the cardiovascular and respiratory system functions of the female elderly in the community dwelling.

• Journal of Advanced Marine Engineering and Technology
• /
• 제39권5호
• /
• pp.563-569
• /
• 2015

A chemical reaction occurring in CSTR (Continuous Stirred Tank Reactor) is significantly affected by the concentration, temperature, pressure, and reacting time of materials, and thus it has strong nonlinear and time-varying characteristics. Also, when an existing linear PID controller with fixed gain is used, the performance could deteriorate or could be unstable if the system parameters change due to the change in the operating point of CSTR. In this study, a technique for the design of a fuzzy PD plus I controller was proposed for the temperature control of a CSTR process. In the fuzzy PD plus I controller, a linear integral controller was added to a fuzzy PD controller in parallel, and the steady-state performance could be improved based on this. For the fuzzy membership function, a Gaussian type was used; for the fuzzy inference, the Max-Min method of Mamdani was used; and for the defuzzification, the center of gravity method was used. In addition, the saturation state of the actuator was also considered during controller design. The validity of the proposed method was examined by comparing the set-point tracking performance and the robustness to the parameter change with those of an adaptive controller and a nonlinear proportional-integral-differential controller.