• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1996년도 춘계학술대회
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• pp.199-202
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• 1996

Artificial hearts are intended for use in patients with severe forms of heart disease for which no surgical repair is possible. The moving-actuator pump was developed to decrease the overall volume size of the electromechanical total artificial heart (TAH) by eliminating the occupied space of the fixed-actuator in the conventional pusher-plate type pump. In our pump, the actuator moves back and forth for alternative ejections of left and right ventricles. The problem of fitting the TAH to atrial remnants and arterial vessels could also be improved by circular or penduluous mot ion of the actuator instead of linear mot ion of the pusher-plate in the conventional pumps. We have evaluated two types of moving- actuator pump; one is a rolling cylinder type, and the other a pendulum type pump. In the rolling cylinder pump, frictional energy loss exists between the pump housing's guide bars and the actuator's end caps, while the bottom rack under the cylindrical actuator increases the height of the pump, the pump is therefor not implantable inside the small chest of human-sized animals with a body weight of less than 70kg. The new human type pump has a penduluous mot ion actuator to correct the above problems while maintaining the advantage of the moving- actuator's small total volume. The totally implantable TAH is composed of a blood pump, a control system and pheriperal equipments. The blood pump, which is constructed by a moving actuator, a right and left blood sac, and four artificial valves, is implanted in the thoracic. In 1988, the first implantation of the rolling cylinder TAH was performed into a female calf weighing 100kg, and the cal f recovered to the degree of voluntary standing and eat ing and survived to 100 hrs. We then survived two female sheep weighing about 63kg with the new human type TAH for three days.

• 한국생산제조학회지
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• 제22권2호
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• pp.235-240
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• 2013

This paper presents a disposable microfluidic infusion pump using the restoring force of elastomeric membrane of Polydimethylsiloxane. Microfluidic infusion pump consists of hydraulic resistance control part, elastomeric blister actuator part, drug inlet and outlet. Expanded elastomeric blister actuator continuously pushes liquid in the chamber to outlet. At same time, microchannel diameter near the outlet was controlled by thin elastomeric membrane in hydraulic resistance control part. Eventually flow rate of infused liquid is controlled by air pressure. In experimental study, the amount of the filled liquid in the blister is precisely controlled by the height of the blister. Flow rate of infused liquid could be controlled, that is, controlled release of the drug over time was possible by adjusting hydraulic resistance and restoring pressure with the blister actuator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.1023-1025
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• 1998

This paper presents the fabrication of a micro pump consisting of a pair of Al f1ap wave and a phase change actuator. The phase change actuator is composed of a heater, a silicone rubber diaphragm and a working liquid chamber. The diaphragm is actuated by the evaporation and the condensation of the working liquid. The actuator pumps fluid through the valves. The micro pump is fabricated by the anisotropic etch, the boron deposition and the metal evaporation. The forward and the backward flow characteristics of the f1ap valves were obtained. Also, the flow rate of the micro pump has been measured. When the square wave input of 12 V, 60% duty ratio and 0.2 Hz is applied, the average flow rate is $0.15{\mu}{\ell}/sec$ for zero pressure difference.

• 대한의용생체공학회:의공학회지
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• 제26권6호
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• pp.393-398
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• 2005

An electromechanical type is the most useful mechanism in the various pumping mechanisms. It, however, requires a movement converting system including a ball screw, a helical cam, or a solenoid-beam spring, which makes the device complex and may lessen reliability. Thus, the authors have hypothesized that an electromagnetic actuator mechanism can eliminate the movement converting system and that thereby enhance the mechanical reliability and operative simplicity of an electro­pneumatic pump. The purpose of this study was to show a novel application of electromagnetic actuator mechanism in pulsatile pump and to provide preliminary data for further evaluations. The electromagnetic actuator consists of stators with a single winding excitation coil and movers with a high energy density neodymium-iron-boron permanent magnet. A 0.5mm diameter wire was used for the excitation coil, and 1000 turns were wound onto the stators core with parallel. A prototype of extracorporeal electro-pneumatic pump was constructed, and the pump performance tests were performed using a mock system to evaluate the efficiency of the electromagnetic actuator mechanism. When forward and backward electric currents were supplied to the excitation coil, the mover effectively moved back and forth. The nominal stroke length of the actuator was 10mm. The actuator dimension was 120mm in diameter and 65mm in height with a mass of 1.4kg. The prototype pump unit was 150mm in diameter, 150mm in thickness and 4.5kg in weight. The maximum force output was 70N at input current of 4.5A and the maximum pump rate was 150 beats per minute. The maximum output was 2.0 L/minute at a rate of 80bpm when the afterload was 100mmHg. The electromagnetic actuator mechanism was successfully applied to construct the prototype of extracorporeal electro­pneumatic pump. The authors provide the above results as a preliminary data for further studies.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.247-251
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• 2008

This paper presents a micro air pump actuated by PZT actuator (synthetic jet actuator) for air supply for micro fuel cells. The synthetic jet actuators are usually created by a traditional PZT-driven actuator, which consists of a small cylindrical cavity, in/outlet channel and PZT diaphragms. To design the micro air pump, a numerical analysis has been conducted for flow characteristics with respect to various geometries. A prototype of the micro air pump, with a size of $mm{\times}mm{\times}mm$, was fabricated by PDMS replication process and was conducted performance test. To control the PZT actuator, we used the SP4423 micro chips that can be amplified input voltage to reduce the controller size and the power consumption. With a voltage of 3V at 100Hz, the air pump's pumping pressure is 600pa and its power consumption is only 0.1mW.

• 로봇학회논문지
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• 제16권2호
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• pp.79-85
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• 2021

Soft fluidic actuators (SFAs) are widely utilized in various areas such as wearable systems due to the inherent compliance which allows safe and flexible interaction. However, SFA-driven systems generally require a large pump, multiple valves and tubes, which hinders to develop a miniaturized system with small range of motion. Thus, a highly integrated soft actuator needs to be developed for implementing a compact SFA-driven system. In this study, we propose an electro-hydraulic soft zipping actuator that can be used as a miniature pump. This actuator exerts tactile force as a dielectric liquid contained inside the actuator pressurized its deformable part. In addition, the proposed actuator can estimate the internal dielectric liquid thickness by using its self-sensing function. Besides, the electrical characteristics and driving performance of the proposed system were verified through experiments.

• Tribology and Lubricants
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• 제14권4호
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• pp.15-22
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• 1998

Recently, the importance of variable displacement piston pump is increasing in industrial world. Especially, most consumers require various range of pressures and flow rates. Pressure compensator is a system controlling flow rate in piston pump at low cost and, therefore, satisfies the need of consumers. However, the system has serious problems, such as response and leakage. The response and leakage are affected by clearance between actuator piston and cylinder, roughness of surface, and spool overlap. In this paper, these effects are investigated experimentally, and optimal clearance and chamfer is obtained. While diameter of cylinder is fixed and diameter of actuator piston is changed in this experiment, response and leakage are measured. Also parameters such as roughness and processing accuracy are changed for piston of fixed clearance. Experimental setup modelled into several parts of actuator piston, cylinder, spool, and swash plate. Input pressure is changed by function generator and proportional valve. The result of this experiment shows that leakage increases very much in proportion to the increase of clearance, and especially leakage occurs enormously when clearance is more than 0.002. The response is not good because as clearance increases leakage increases and as clearance decreases viscous damping effect increases. Accordingly, it is found out that optimal clearance range exists for tile response, within about 0.0012∼0.0014, at this time. Futhermore, the better roughness and geometrical accuracy of actuator piston are, the smaller are leakage and friction. The paper informs that response and leakage are influenced by and geometrical accuracy of actuator piston, roughness of surface, and the clearance between actuator piston and cylinder, and that optimal design of actuator piston in the pressure compensator is possible.

• Journal of Chest Surgery
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• 제28권6호
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• pp.542-548
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• 1995

The goal of this study is to develop an effective control system for cardiac output regulation based upon the preload and afterload conditions without any transducers and compliance chambers in the moving actuator type total artificial heart. Motor current waveforms during the actuator movement are used as an input to the automatic control algorithm. While the current waveform analysis is performed, the stroke length and velocity of the actuator are gradually increased up to the maximum pump output level. If the diastolic filling rate of either right or left pump begins to exceed the venous return, atrial collapse will occur. Since the diastolic suction acts as a load to the motor, this critical condition can be detected by analyzing the motor current waveforms. Every time this detection criterion is met, the control algorithm decreases the stroke velocity and length of the actuator step by step just below the critical detection level. Then, they start to increase. In this way the maximum pump output under given venous return can be achieved. Additionally the control algorithm provides some degree of afterload sensitivity. If the aortic pressure is detected to exceed 120 mmHg, the stroke length and velocity decrease in the same way as the response to the preload. Left-right pump output balance is maintained by proper adjustment of the asymmetry of the stroke angle. In the mock circulatory test, this control system worked well and there was a considerable range of stroke volume difference with adjustment of the asymmetry value. Two ovine experiments were performed. It was confirmed that the required cardiac output regulation according to the venous return could be achieved with adequate detection of diastolic function, at least in the in vivo short-term survival cases[2-3 days . We conclude that this control algorithm is a promising method to regulate cardiac output in the moving actuator type total artificial heart.

• 로봇학회논문지
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• 제16권1호
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• pp.29-34
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• 2021

Traditional actuation system such as electric and pneumatic actuator has obvious advantages and disadvantages. To combine advantages and compensate disadvantages of the traditional actuation, a pneumatic actuation system with an internal air pressure source is noteworthy approach. In this paper, a soft pneumatic actuation system based on origami pump is described for haptic feedback glove. To improve wearability, an origami pump is introduced because the origami pump is much lighter than air compressor. The miniaturized electric actuation system is also designed with 3D printed planetary gear in order to reduce the volume of the system. To figure out the performance of the system, shrinkage distance of origami pump was measured with vision camera. The pressure in the origami pump was also estimated to understand the performance of the system.

• 한국항공우주학회지
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• 제43권11호
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• pp.963-970
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• 2015

본 연구에서는 압전유압펌프의 챔버부, 체크밸브, 부하, 펌프구동제어기 등 유압펌프 전체 구성품의 해석 모델링을 통하여 브레이크용 소형 압전유압펌프의 가압 동특성을 해석하였다. 가압 동특성을 해석하기 위해 먼저 적층형 압전작동기가 챔버내에서 압력을 형성하는 과정을 모델링하였다. 체크밸브 개도에 따른 유량계수 식을 얻기 위해, 유한요소코드 해석을 통해 체크밸브 압력분포 및 유동결과를 얻은 후 체크밸브 유량계수식을 커브 피팅으로 유도하였다. 또한 부하압력을 피드백 받아 작동기 입력전압을 제어하여 부하압력이 입력명령 압력을 잘 추종하도록 펌프구동제어기를 설계하였다. 시뮬레이션 결과 브레이크 작동에 필요한 정상작동압력까지 도달하는데 걸리는 시간은 약 0.03ms 정도이다. 본 연구에서 얻어진 해석 시뮬레이션 결과는 실제 실험결과와 비교를 통해 타당성을 검증하였다.