• Smart Structures and Systems
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• 제9권4호
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• pp.373-392
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• 2012

Tracking control of systems with variable stiffness hysteresis using a gain-scheduled (GS) controller is developed in this paper. Variable stiffness hysteretic system is represented as quasi linear parameter dependent system with known bounds on parameters. Assuming that the parameters can be measured or estimated in real-time, a GS controller that ensures the performance and the stability of the closed-loop system over the entire range of parameter variation is designed. The proposed method is implemented on a spring-mass system which consists of a semi-active independently variable stiffness (SAIVS) device that exhibits hysteresis and precisely controllable stiffness change in real-time. The SAIVS system with variable stiffness hysteresis is represented as quasi linear parameter varying (LPV) system with two parameters: linear time-varying stiffness (parameter with slow variation rate) and stiffness of the friction-hysteresis (parameter with high variation rate). The proposed LPV-GS controller can accommodate both slow and fast varying parameter, which was not possible with the controllers proposed in the prior studies. Effectiveness of the proposed controller is demonstrated by comparing the results with a fixed robust $\mathcal{H}_{\infty}$ controller that assumes the parameter variation as an uncertainty. Superior performance of the LPV-GS over the robust $\mathcal{H}_{\infty}$ controller is demonstrated for varying stiffness hysteresis of SAIVS device and for different ranges of tracking displacements. The LPV-GS controller is capable of adapting to any parameter changes whereas the $\mathcal{H}_{\infty}$ controller is effective only when the system parameters are in the vicinity of the nominal plant parameters for which the controller is designed. The robust $\mathcal{H}_{\infty}$ controller becomes unstable under large parameter variations but the LPV-GS will ensure stability and guarantee the desired closed-loop performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.1206-1208
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• 2001

Direct torque control(DTC) of AC motor has the fast torque and flux dynamic responses even though it has very simple scheme to implement. DTC is also very simple in its implementation because it needs only two hysteresis comparators and switching vector table for both flux and torque control. The amplitude of hysteresis band greatly influences on the drive performance such as flux and torque ripple, switching frequency and current harmonics. Therefore, authors analysis flux and torque hysteresis bands is suggested considering switching frequency and harmonic distortion of currents.

• 전력전자학회논문지
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• 제3권4호
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• pp.330-337
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• 1998

히스테리시스 제어를 사용하는 Buck 컨버터의 평균모델을 위한 Duty Cycle 모델이 수학적으로 구해진다. 이 모델은 시간영역에서 연속 전도 모드와 불연속 전도 모드 모두를 동시에 시물레이션할 수 있다. 또한, SABER의 MAST언어를 이용하여, 제안된 모델의 템플릿이 제시되며, 이 템플릿은 시간영역이나 주파수 영역의 해석을 위해 사용되어질 수 있다. 이 템플릿의 정확성을 컴퓨터 시뮬레이션을 통하여 증명한다.

• 한국정밀공학회지
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• 제14권10호
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• pp.50-57
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• 1997

A fast tool servo (FTS) for diamond turning improves machining accuracy by quickly compensating relative position errors between the cutter and the workpiece. Therefore, the FTS needs to have large band-width with good tracking performance. Serious hysteresis nonlinearity of PZT actuators used in the FTS, however, deteriorates fast tracking performance. Several types of feedforward hysteresis compensators and feedback controllers are tested to improve tracking performance. Through simulations and experiments, control structure which yields the smallest tracking error is selected. The maximum peak to peak error in tracking a sinusoidal waveform is reduced by one fifth compared to that of a regular PID controller.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.93-98
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• 1996

This paper presents active silencer by hysteresis control method using DSP-scheme and shows it audible noise reduction effect. Pentium processor and sound blaster 16 are used for its implementation. The sound blaster 16 executes A/D, D/A conversion and is used operating source of loudspeaker for cancelling.

• 한국소음진동공학회논문집
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• 제15권3호
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• pp.290-296
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• 2005

This paper proposes the modeling scheme of the Miniature Universal Testing Machine (MUTM) composed of 36 thin-beam-type bimorph PZTs and the control algorithm to minimize the residual vibration of the MUTM in the dynamic testing of specimens. In the operation of the MUTM, hysteresis, residual displacement and vibration of it are major issues. From the analysis of the MUTM behaviors, the hysteresis is described by the curving fitting scheme with the function of an input voltage. The dynamic characteristics of the MUTM are identified by the frequency domain modeling technique based on the experimental data. The interested bandwidth is focused on 125-315HZ for effective modeling and control. For the robust vibration control of the MUTM, the sliding mode control and the Kalman filter as observer are proposed. The paper also proposes the best input signal type to operate the MUTM effectively. The feasibility of the proposed modeling scheme and control algorithm are tested and verified experimentally.

• 한국기계가공학회지
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• 제16권5호
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• pp.78-84
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• 2017

Compared to other types of power, hydraulic energy is the most commonly used for heavy vehicles and ships because it has fewer location and space constraints, and its controllability can be maintained even under adverse conditions. Operators have controlled a main control valve of ship winches by pushing or pulling the lever, which is directly connected to the spool. However, because of the spatial arrangement, the importance of remote control valves has emerged. In this paper, experiments of the hysteresis characteristics were performed by analyzing the remote-control valve using a valve tester and RA2300. The validity was verified by comparing with the analytical model using SimulationX as the hydraulic analysis program. This study examined the effects of the spool's notch (Non, End-mill, and Spherical) and the effects of stiffness and pre-load of the spool spring on Spool stroke, open area, and hysteresis characteristics. It is considered possible to reduce the cost and the, trial and error process in designing remote-control valves in the future.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.476-481
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• 2004

This paper proposes the modeling scheme of the Miniature Universal Testing Machine (MUTM) composed of 36 thin-beam-type bimorph PZTs and the control algorithm to minimize the residual vibration of the MUTM in the dynamic testing of specimens. In the operation of the MUTM, hysteresis, residual displacement and vibration of it are major issues. From the analysis of the MUTM behaviors, the hysteresis is described by the curving fitting scheme with the function of an input voltage. The dynamic characteristics of the MUTM are identified by the frequency domain modeling technique base on the experimental data. The interest bandwidth is focused on 125-315HZ for effective modeling and control. For the robust vibration control of the MUTM, the sliding mode control and the Kalman filter as observer are proposed. The paper also proposes the best input signal type to operate the MUTM effectively. The feasibility of the proposed modeling scheme and control algorithm are tested and verified experimentally.

• Advances in aircraft and spacecraft science
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• 제5권4호
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• pp.431-444
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• 2018

Numerical simulations have been conducted to study the unstart/restart characteristics of an over-under turbine-based combined-cycle propulsion system (TBCC) inlet during the inlet transition phase. A dual-solution area exists according to the Kantrowitz theory, in which the inlet states may be different even with the same input parameters. The entire transition process was divided into five stages and the unstart/restart hysteresis loop for each stage was also obtained. These loops construct a hysteresis surface which separates the operating space of the engine into three parts: in which a) inlet can maintain a started state; b) inlet keeps an unstarted state; c) inlet state depends on its initial state. During the transition, the operation of the engine follows a certain order with different backpressures and splitter angles, namely control route, which may result in disparate inlet states. Nine control routes with different backpressures and transition stages were designed to illuminate the route-dependent behavior of the inlet. The control routes operating towards the unstart boundary can make the inlet transit from a started state into an unstarted one. But operating backward the same route cannot make the inlet restart, additional effort should be made.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.555-556
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• 2013