• Title, Summary, Keyword: hysteresis loop

Search Result 381, Processing Time 0.035 seconds

Improvement of the Performance of Hysteresis Compensation in SMA Actuators by Using Inverse Preisach Model in Closed - Loop Control System

  • Ahn Kyoung-Kwan;Kha Nguyen-Bao
    • Journal of Mechanical Science and Technology
    • /
    • v.20 no.5
    • /
    • pp.634-642
    • /
    • 2006
  • The aim of this paper is to increase the performance of hysteresis compensation for Shape Memory Alloy (SMA) actuators by using inverse Preisach model in closed-loop control system. This is used to reduce hysteresis effects and improve accuracy for the displacement of SMA actuators. Firstly, hysteresis is identified by numerical Preisach model implementation. The geometrical interpretation from first order transition curves is used for hysteresis modeling. Secondly, the inverse Preisach model is formulated and incorporated in closed-loop PID control system in order to obtain desired current-to-displacement relationship with hysteresis reducing. The experimental results for hysteresis compensation by using this method are also shown in this paper.

Hysteresis Compensation Control of Piezoelectric Actuators (피에조일렉트릭 액츄에이터의 히스테리시스 보상 제어)

  • 임요안;최기흥;최기상
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • /
    • pp.219-224
    • /
    • 1996
  • Piezoelectric actuators exhibit limited accuracy in tracking control due to their hysteresis nonlinearity. In this study a digital tracking control approach for a piezoelectric actuator based on incorporating a feedback linearization loop with a PID feedback controller is presented. The hysteresis nonlinearity of the piezoelectric actuator is modeled in the feedback compensation loop using the Maxwell slip model. Experiments were performed on a piezoelectric 2-axis linear positioner for tracking linearly decaying sinusoidal waveforms and circles. The experimental results show that the tracking control performance is noticeably improved by augmenting the feedback loop with a model of hysteresis in the feedback compensation loop.

  • PDF

Major B-H Loop Measurement of Toroidal Shape Magnetic Powder Core (토로이드형 분말코어의 Major B-H Loop 측정)

  • Son, Derac
    • Journal of the Korean Magnetics Society
    • /
    • v.24 no.3
    • /
    • pp.76-80
    • /
    • 2014
  • Toroidal cores made of metallic powder requires large magnetic field strength up to few decade kA/m to obtain major hysteresis loop. To overcome thermal heat generation problem from large exciting current during measurement, we have employed a real time hysteresis loop tracer which can digitize and calculate B-H signals in personal computer as real time. For example, when we magnetize specimen at 10 Hz frequency, we could display hysteresis loops 10 times per second. Using the real time hysteresis loop tracer, we could measure major hysteresis loop of toroidal shape metallic powder core at maximum flux density or maximum magnetic field strength to be measured within 5 second not to significant increasement of specimen temperature due to the heat dissipation from coil windings. For the constructed hysteresis loop tracer, we could measure hysteresis loop at magnetic field strength higher than 50 kA/m for the toroidal shape specimen.

Rheological Studies on the Aqueous Suspension of Korean Bentonite (국산벤토나이트 현탁액의 유동학적 성질)

  • Kim, Eun-Hee;Rhee, Gye-Ju
    • YAKHAK HOEJI
    • /
    • v.34 no.5
    • /
    • pp.302-310
    • /
    • 1990
  • A study has been made of the Korean bentonite aqueous suspension contrast with American bentonite by means of XRD IR swelling, gel formation and rheogram at various conditions such as concentration, temperature and pH. The Korean bentonite was identified as montmorillonite clay containig a small proprotion of crystoballite and mordenite, and its swelling power were acceptable for requirements of Korean pharmacopeia regulations though its values were not satisfied. Korean bentonite swelled to 10 times and American one did to 15 times compared to its bulkiness of powder. The rheogram of Korean bentonite suspension reveals bulged pseudoplatic flow with yield value at higher concentration and pseudoplastic flow without yield value at lower concentration. The higher the concentration, the greater were the apparent viscosity and hysteresis loop. Korean bentonite suspension showed insignificant temperature dependence on both apparent viscosity and hysteresis loop and it was more temperature dependent on viscosity but less on hysteresis loop than those of American sample. The pH dependence was so high on viscosity that apparent minimum value was near pH 7 and maximum value at pH 3 or 7. The hysteresis loop appeared minimum over the pH range 5-7 and maximum near pH 3 or 11. The Korean bentonite was inferior to the American bentonite in swelling volume, gel formation, thioxotropy, however, it would be possible to improve the quality of Korean bentonite by developing the method of purification for bentonite clay.

  • PDF

A 500 MHz-to-1.2 GHz Reset Free Delay Locked Loop for Memory Controller with Hysteresis Coarse Lock Detector

  • Chi, Han-Kyu;Hwang, Moon-Sang;Yoo, Byoung-Joo;Choe, Won-Jun;Kim, Tae-Ho;Moon, Yong-Sam;Jeong, Deog-Kyoon
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • v.11 no.2
    • /
    • pp.73-79
    • /
    • 2011
  • This paper describes a reset-free delay-locked loop (DLL) for a memory controller application, with the aid of a hysteresis coarse lock detector. The coarse lock loop in the proposed DLL adjusts the delay between input and output clock within the pull-in range of the main loop phase detector. In addition, it monitors the main loop's lock status by dividing the input clock and counting its multiphase edges. Moreover, by using hysteresis, it controls the coarse lock range, thus reduces jitter. The proposed DLL neither suffers from harmonic lock and stuck problems nor needs an external reset or start-up signal. In a 0.13-${\mu}m$ CMOS process, post-layout simulation demonstrates that, even with a switching supply noise, the peak-to-peak jitter is less than 30 ps over the operating range of 500-1200 MHz. It occupies 0.04 $mm^2$ and dissipates 16.6 mW at 1.2 GHz.

An Open-Loop Method for Point-to-Point Positioning of a Piezoelectric Actuator

  • Henmi, Nobuhiko;Tanaka, Michihiko
    • International Journal of Precision Engineering and Manufacturing
    • /
    • v.8 no.2
    • /
    • pp.9-13
    • /
    • 2007
  • We describe how to control a piezoelectric actuator using the open-loop method for point-to-point positioning. Since piezoelectric actuators have nonlinear characteristics due to hysteresis and creep between the input voltage and the resulting displacement, a special method is required to eliminate this nonlinearity for an open-loop drive. We have introduced open-loop driving methods for piezoelectric actuators in the past, which required a large input voltage and an initializing motion sequence to reset the state of the actuator before each movement. In this paper, we propose a new driving method that uses the initializing state. This method also utilizes the overshoot from both the upward and downward stepwise drives. Applying this method., we obtained precise point-to-point positioning without the influence of hysteresis and creep.

Precision Position Control of Piezoelectric Actuator Using Feedforward Hysteresis Compensation and Neural Network (히스테리시스 앞먹임과 신경회로망을 이용한 압전 구동기의 정밀 위치제어)

  • Kim HyoungSeog;Lee Soo Hee;Ahn KyungKwan;Lee ByungRyong
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.22 no.7
    • /
    • pp.94-101
    • /
    • 2005
  • This work proposes a new method for describing the hysteresis non-linearity of a piezoelectric actuator. The hysteresis behaviour of piezoelectric actuators, including the minor loop trajectory, are modeled by geometrical relationship between a reference major loop and its minor loops. This hysteresis model is transformed into inverse hysteresis model in order to output compensated voltage with regard to the given input displacement. A feedforward neural network, which is trained by a feedback PID control module, is incorporated to the inverse hysteresis model to compensate unknown dynamics of the piezoelectric system. To show the feasibility of the proposed feedforward-feedback controller, some experiments have been carried out and the tracking performance was compared to that of simple PTD controller.

The study on effects of porosity, strain and grain size on B-H Hysteresis Ioop (기공율, 응력 및 입자 크기가 B-H Hysteresis loop 특성에 미치는 영향 연구)

  • 김성재;정명득;백종규
    • Journal of the Korean Magnetics Society
    • /
    • v.4 no.2
    • /
    • pp.89-93
    • /
    • 1994
  • Effects of density, inner-stress, and grain size on B-H hysteresis loop properties of Mg-ferrite were investigated. As the sintered bulk density increase, coercive force($H_c$) decreasand squareness ratio increase. Coercive force was very dependent on inner-stress in sintered body, so coercive force increase from 1.95[Oe] to 4.35[Oe] when inner stress present in bulk, however, the squareness ratio was almost not changed Coercive force and squareness ratio were independent on grain size of sintered body which is between 6-11[$\mu\textrm{m}$]

  • PDF