• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.476-481
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• 2001

This research is concerned with development of the active vibration absorber using piezoelectric actuators. This active isolation system consists of a-pairs of PZT actuators bonded on a S-shaped aluminum plate and the passive damping material. The active system is connected to the passive system in series. In this paper, one of the popular control techniques which have been successfully applied to the smart structure is the Positive Position Feedback(PPF) control. The digital PPF control lows downloaded to the DSP chip and a main program, which runs SISO PPF algorithm. The structure and dynamic characteristics of the proposed active vibration isolation system and described in detail. To demonstate the effectiveness of the active vibration control, the PPF controller is first employed. Experimental results show that the active vibration isolation is possible by means of the proposed system.

• 한국정밀공학회지
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• 제10권2호
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• pp.14-21
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• 1993

Pneumatic actuators have greater power to weight ratio than electric ones, but they have been rarely used as robotic actuators because of poor accuracy resulted from nonliearity of air. On the other hand, electric servo motors have glld controllability, but they have poor power to weight ratio. For the heavy load handling robot a combined actuating method was developed for vertical and horizontal axes of RISTBOT-ll which handles up to 250kgf load. In this paper, the control method is implemented and analyzed for the manufactured heavy load handling robot.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 제2회 학술대회 논문집 일렉트렛트 및 응용기술전문연구회
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• pp.1-8
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• 2000

Automotive electronics as we know it today encompasses a wide variety of devices and systems. Key to them all, and those yet to come. is the ability to sense and measure accurately automotive control parameters. In other words, sensors and actuators are the heart of any automotive electronics application. The important of sensors and actuators cannot be overemphasized. The future growth of automotive electronics is arguably more dependent on sufficiently accurate and low-cost sensors and actuators than on computers, controls, displays, and other technologies. Without them, all of controls system - engine. transmission. cruise, braking, traction, suspension, steering, lighting, windshield wipers, air conditioner/hearter - would not be possible. Those controls, of course, are key to car operation and they have made cars over the years more drivable, safe, and reliable. In this lecture, the principle and future trends of electronic control gasoline engine will be discuss.

• 전기학회논문지P
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• 제57권3호
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• pp.250-254
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• 2008

Robot actuators are significantly important with respect to whole control system performance. This paper presents an adaptive control approach for flexible robot actuators with time-varying spring and damping nature. We first represent a perturbed system model with assumption that its information are partially known. Nominal model reference control method is employed for deriving our adaptive control law. We carry out numerical simulation to evaluate the proposed control system and compare simulation results to a well-known control method for demonstrating its effectiveness.

• Journal of applied mathematics & informatics
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• 제7권3호
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• pp.739-763
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• 2000

We are concerned with mathematical analysis related to the bi-pointwise control for a mixed type of wave equation. In particular, we are interested in the systematic build-up of the bi-pointwise control actuators;one at the boundary and the other at the interior point simultaneously. The main purpose is to examine Hilbert Uniqueness Method for the setting of bi-pointwise control actuators and to establish relevant algorithm based on our analysis. After discussing the weak solution for the state equation, we investigate bi-pointwise control mechanism and relevant mathematical analysis based on HUM. We then proceed to set up an algorithm based on the conjugate gradient method to establish bi-pointwise control actuators to halt the system.

• Journal of Mechanical Science and Technology
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• 제20권5호
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• pp.634-642
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• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.977-981
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• 1996

A load sensing hydraulic system is widely used to military and commercial mobile applications fur its high running efficiency. Although concept and general control schemes are well known, the poor maneuverability of simultaneous multioperation of actuators still remains to be solved. In this paper, a new control algorithm is proposed to prevent the saturation of the system in such operating conditions, in which the total required flowrate of actuators may exceed the pump supply flowrate. The effectiveness of the proposed algorithm is verified through experiments.

• 한국정밀공학회지
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• 제22권2호
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• pp.113-119
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• 2005

A crack emanating from an internal electrode or a conducting damage path in ferroelectric ceramic actuators is analyzed. The boundary of the domain switching zone near the edge of the internal electrode in a ceramic multilayer actuator is determined based on the nonlinear electric theory. The stress intensity factor induced by a ferroelectric domain switching under small scale conditions is numerically obtained for flaws of various sizes near the electrode edge. It is found that stress intensity factor near the crack tip depends on the material property of the electrical nonlinearity.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권9호
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• pp.511-519
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• 2003

In this paper, we considered the design of gain scheduled controllers for linear systems with saturating actuators. Our basic idea is to design a control that uses higher control gain when the states are smaller, and lower gain when it is higher. By doing this, we can avoid the saturation and we can improve the performance. First, we derive a control and a reachable set expressed as LMI form, which minimizes not only the L$_2$ gain from the disturbance to the measured output but also the control is never saturated within this reachable set. Next, the reachable set is divided as nested subsets, and at each nested subset, the control gain is designed to minimize the L$_2$ gain and it is never saturated. Finally, the control gain is scheduled according to the status of states, i.e., the subset in which the states are located. A numerical example is presented to show that our gain scheduled control significantly improves the performance.

• 한국정밀공학회지
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• 제31권6호
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• pp.535-541
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• 2014

In this research, three degree-of-freedom parallel spherical robot is developed for an artificial eyeball. The proposed system is comprised of a moving and a base plate, three prismatic actuators, and a ball joint for an angular movement of the moving plate. The vector analysis is employed to investigate the relationship between positions of the actuators and a pose of the moving plate. The required ranges for every actuators are calculated using the derived inverse kinematics in regard to the combination of two different levels for the size of the system component. Then the size of every components is determined from the analyzed trend. PI controller is employed for the position control of the moving plate. Finally the proposed system is verified using an arbitrary path of the angular movement.