Browsing by Author "Chang, Shih-Tse"

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A Feedback Linearization Design for Compressor's Surge Control
(2008)
Liaw, Der-Cherng
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Ren, S. M.
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Chang, Shih-Tse
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電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, input-output feedback linearization scheme is employed to stabilize the instabilities of axial flow compressor, specifically, for the so-called "surge" behavior. Two types of actuators are considered for the study. One is the throttle opening, and the other is the close-coupled valve. The axial flow compressors are found to be feedback linearizable via either of the two control inputs. Overall control law is then proposed to prevent the occurrence of the surge oscillation. Numerical results are also given to demonstrate the effectiveness of the proposed designs.
Bifurcation Analysis of a Centrifugal Compressor
(2011)
Liaw, Der-Cherng
;
Chang, Shih-Tse
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents the local bifurcation analysis of the dynamic behavior for a centrifugal compressor. It is known that the surge phenomenon in compressor dynamics might occur at high pressure rise operation. Under such an operation, slight variation of the driving torque and/or the throttle opening might sharply reduce the compressor efficiency and even damage the system. Local bifurcation analysis of the centrifugal compressor system presented in this paper reveals the existence conditions of surge phenomenon. Bifurcation scenarios of compressor dynamics are also obtained with respect to the variation of driving torque and/or throttle opening, which provide a guide to determine the occurrence of nonlinear phenomena and reveal the stability limit for the compressor dynamics in the practical application. Numerical results demonstrate the linkage between nonlinear dynamical behavior and bifurcation phenomena.
Design of Midcourse Guidance Laws via a Combination of Fuzzy and SMC Approaches
(2010-04-01)
Chen, Chun-Hone
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Liang, Yew-Wen
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Liaw, Der-Cherng
;
Chang, Shih-Tse
;
Xu, Sheng-Dong
Issues regarding the design of midcourse guidance laws for antimissiles are addressed. The antimissile is expected to be guided to a place with a desired direction, where a ballistic missile is predicted to pass in the reverse direction, so that the target can be easily found and locked for terminal interception. The predicted location and direction of a ballistic missile may vary with time, due to information update using a trajectory prediction algorithm. To fulfill the guidance performance, the guidance laws are designed by combining the Takagi-Sugeno (T-S) fuzzy approach and the Sliding Mode Control (SMC) technique. Under the designed guidance law, it is shown that the antimissile is able to be efficiently guided to a specified location and direction, even when the existence of uncertainties and disturbances.
The Steering Control of Vehicle Dynamics via a Lyapunov Redesign Approach
(2009)
Chung, Wen-Ching
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Liaw, Der-Cherng
;
Chang, Shih-Tse
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, Lyapunov redesign method is proposed to control the steering of vehicle. It was observed in Liaw and Chung (2006) that the vehicle dynamics would exhibit the saddle-node bifurcation phenomenon at some front wheel steering angle. This might result in spin and/or instability for vehicle system. Based on the assumption of constant driving velocity, a Lyapunov redesign control law was proposed to stabilize the system dynamics at the bifurcation point for guaranteeing system stability after the appearance of stall. Simulation results for an example model of vehicle dynamics were presented to illustrate the success of the proposed design.
Voltage Tracking Design for Electric Power Systems via SMC Approach
(2009)
Liaw, Der-Cherng
;
Chang, Shih-Tse
;
Huang, Yun-Hua
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a output tracking design for regulating the load voltage of the electric power system. Based on a model of electric power system proposed by Dobson and Chiang (1988), the saddle-node bifurcation and Hopf bifurcations were observed (Wang, et al, 1994) by treating the reactive power as system parameter. Those bifurcations were found to lead to the appearance of the dynamic or the static voltage collapses of the power systems. In construct to the state feedback design at the bifurcation point via the tuning of the Static Var Compensator as proposed in (Saad, et al, 2005), a sliding mode control (SMC) scheme using SVC was employed in this study to construct a load voltage tracking design control law for regulating the load voltage and hence providing the stability of electric power systems. The numerical simulations demonstrated that the proposed control scheme not only could provide the regulation of the load voltage but also prevent and/or delay the appearance of bifurcation phenomena and chaotic behavior.