• International Journal of Precision Engineering and Manufacturing
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• 제8권2호
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• pp.9-13
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• 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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.881-886
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• 2003

Vibration control of plates with a passive electrical damper is presented in this paper. This electrical absorber, piezoelectric patches connected with a resistor and an inductor in series, is analogous to the damped mechanical vibration absorber. For estimating the effectiveness of piezoelectric absorber, the governing equations of motion are derived using a classical laminate plate theory and Hamilton principle. The developed theoretical analyses are validated experimentally for simply-supported aluminum plates in order to demonstrate the performance of passive electrical damper. The result shows that the vibration amplitude is reduced about 14dB for the targeted first vibration mode.

• 대한기계학회논문집A
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• 제27권10호
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• pp.1778-1784
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• 2003

Vibration control of plates with a passive electrical damper is presented in this paper. This electrical absorber, piezoelectric patches connected with a resistor and an inductor in series, is analogous to the damped mechanical vibration absorber. For estimating the effectiveness of piezoelectric absorber, the governing equations of motion are derived using a classical laminate plate theory and Hamilton principle. The developed theoretical analysis is validated experimentally for a simply-supported aluminum plate in order to demonstrate the performance of passive electrical damper. The result shows that the vibration amplitude is reduced about 14dB for the targeted first vibration mode.

• 소음진동
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• 제9권1호
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• pp.70-76
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• 1999

This paper presents a pseudo-sensor-output-feedback(PSOF) method for the vibration suppression of the flexible piezoelectric smart structures. This method reduces the modeling errors using pseudo sensors in the output equation formulation. It also reduces computation time in practice. since the output equation does not need the state observer required in the state space equation. Experimental works are performed for the validation of theoretical predictions with the piezoelectric sensor and actuator bonded on the cantilever beam. An algorithm based on the sliding mode control theory is developed and analyzed for the robustness to the modeling errors and parameter uncertainties. This study also discusses the characteristics of the active and semi-active systems.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1995년도 추계학술대회 논문집
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• pp.18-23
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• 1995

The study was carried out to develope a precision positioning apparatus, consisting of DC servo motor and piezoelectric actuator. This system is composed of fine and coarse apparatus, measurement system and control system, Piezoelectric actuator is designed for fine positioning. Coarse positioning using lead screw is drived by DC servo motor. Control system output a signal from laser interferometer and microsense to amplifier of DC servo motor and piezoelectric actuator after digital signal processing(DSP). Resolution of this apparatus measure with laser interferometor and microsense

• 한국정밀공학회지
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• 제20권4호
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• pp.59-67
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• 2003

This paper presents a new approach for the use of smart materials, piezoelectric materials of PVDF and PZT, for vibration attenuation of a planar parallel manipulator. Since lightweight linkages of parallel manipulators deform under high acceleration/deceleration, an active damper is needed to attenuate vibration due to structural flexibility of linkages. Based on the dynamic model of a planar parallel manipulator, an active damping controller is developed, which consists of a PD feedback control scheme, applied to linear electrical motors, and a linear velocity feedback (L-type) scheme applied to either PVDF layer or PZT actuator(5). Simulation results show that piezoelectric materials yield good damping performance, resulting in precise manipulations of a planar parallel manipulator.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.195-200
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• 2008

This paper presents motion control of the Inchworm composed of the piezoelectric actuators and mechanical elements. Piezoelectric actuator shows nonlinear response characteristics including hysteresis due to the ferroelectric characteristics. This paper proposes feedback control scheme to improve the ability of tracking response to complex input signal and suppress the phenomenon of hysteresis using the sliding mode control technique with the integrator. The sliding mode control system has the limit to minimize both the settle time and overshoot. For making up this limit, this paper also suggests input shaping technique suitable to the inchworm control system.

• 한국소음진동공학회논문집
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• 제15권7호
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• pp.878-884
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• 2005

This paper presents an algorithm for the precision motion control based on the dynamic characteristics of piezoelectric actuators in the inchworm. The dynamic characteristics are identified by the frequency domain modeling technique using the experimental data. For the motion control, the hysteresis behavior is compensated by the inverse hysteresis model. The dynamic stiffness of an inchworm is generally low compared to its driving condition, so mechanical vibration may degenerate the motion accuracy of the inchworm. The Sliding mode controller and the Kalman filter are designed for motion control of the inch-worm.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.531-536
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• 2005

The purpose of this paper is to improve the hysteresis characteristics of a stack type piezoelectric actuator using system identification and tracking control. Recently, several printing methods that cost less and are faster than previous semiconductor processes have been developed for the production of electric paper and RFID. The system proposed in this study prints by spraying the molten metal, and consists of a nozzle, heating furnace, operating actuator, and an XYZ 3-axis stage, As an operating system, the piezoelectric(PZT) method has very valuable uses. However, the PZT actuator has a very big hysteresis characteristic due to the ferroelectric characteristics of the PZT element. This causes problems in the system position control characteristics and deteriorates the performance of the system. In this study, an investigation was conducted to improve the hysteresis characteristics of the PZT actuator that has an output displacement for the input voltage. The study proposed a inverse hysteresis model, a mathematic modeling method that can express the geometric relationship between voltage and displacement, in order to reduce the hysteresis of the PZT actuator. In addition, system identification and PID control methods were examined. Also, it was confirmed that the proposed control strategy gives good precision position control performance.

• 한국정밀공학회지
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• 제14권1호
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• pp.119-125
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• 1997

This paper deals with an experimental investigation on an active vibration control of ahybrid smart structure(HSS) via an electro-rheological fluid actuator(ERFA) and a piezoelectric film actuator(PFA). Firstly, an HSS is constructed by inserting a silicone oil-based electro-rheological fluid into a hollow can- tilevered beam and perfectly bonding piezoelectric films ofn the upper and lower surfaces of the beam as an actuator and a sensor, respectively. The control scheme of the ERFA tuning stiffness and damping charac- teristics of the HSS with imposed electric fields is formulated as a function of excitation frequencies on the basis of field-dependent respnses. On the other hand, as for the control scheme of the PFA permitting control voltages to generate axial forces or bending moments for suppressing deflections of the HSS, a neuro sliding mode controller(NSC) is employed. Furthermore, an experimental implementation activating the ERFA and the PFA independently is established to carry out an active vibration control in both the transient and forced vibrations. The experimental results exhibit a superior ability of the gtbrid actuation system to tailor elastodynamic response characteristics of the HSS rather than a single class of actuator system alone.