• 한국정밀공학회지
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• 제23권5호
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• pp.184-189
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• 2006

This research presents the performance analysis of the linear type pneumatic actuators that are used in semi-conductor assembly line to transfer some product with high accuracy. To increase positioning and repetitive accuracies, a cross roller guide is implemented inside the pneumatic actuator. The finite element method is used to verify the force against working moments, and reliability analysis is performed to classify the breakdown cases. Also, reliability, failure rate, probability density function, and $B_{10}$ to life are estimated under the boundary of thrust or air leakage conditions. In this study, the failure probabilistic function of the pneumatic actuators is analyzed using Weibull distribution.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1455-1458
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• 1996

In this paper trajectory tracking control problems are described for a robot manipulator by using pneumatic actuator. Under the assumption that the so-called independent joint control is applied to the control system, the dynamic model for each link is identified as a linear second-order system with input time-delay by the step response. Then, an optimal servo controller is designed by taking account of such a time-delay. The effectiveness of the proposed control method is illustrated through some simulations and experiments for the robot manipulator.

• 연구논문집
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• 통권27호
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• pp.153-166
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• 1997

In industry pneumatic control system has become a important means to obtain automation because of its simplicity, fast speed and low cost. However Due to of the compressibility of air and damping friction between moving parts, it is difficult to achieve high speed driving, accurate positioning and stopping without overshoot in one pneumatic control system. This paper describes the dynamic behaviors of pneumatic linear actuator. The results will be very useful in the prediction of actuated dynamics and for the manufacturers to improve the techniques in their redesign and get better performance. Also, the experimental data is very important for the dynamic simulation and theoretical analysis.

• 대한기계학회논문집A
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• 제20권10호
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• pp.3186-3198
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• 1996

When a robot is to have contact with its enviornment, such as a medi-care robot, it would be advantageous for the robot to have a high compliance. For this reason, a robot having not only a flexible link but also an actuator with compliance, is desirable. This paper is concerned with the position and vibration control of 1 degree of freedom flexible robot using a pneumatic artificial muscle actuator. The dynamics of the manipulator assumed to be and Euler-Bernoulli beam are derived on the basis of the linear mathematical modle. Although this pneumatic artifical muscle actuator has many merits for the compliance robot, it is difficult to make an effective control scheme of this system because of ths nonlinearity and uncertainty on the dynamics of the actuator. By designing a controller using .mu.-synthesis, robust performance against measurement noise, various modeling uncertainties on the dynamics of the servo valve, actuator and mainpulator, is achieved. The effectiveness of the proposed control method is illustrated through simulations and experiments.

• 동력기계공학회지
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• 제11권3호
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• pp.59-65
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• 2007

In this study, 6-DOF simulator using pneumatic cylinder driving apparatus was manufactured because a pneumatic cylinder driving apparatus is superior to electric driving motor and hydraulic actuator, which used in traditional 6-DOF simulator, in competitive price and acceleration performance, and, 6-DOF motion can be realized at a low price in case that relatively low load is imposed on the simulator. The possible range of pose control of the simulator was investigated by inverse kinematics, and, it was controlled by a linear controller derived from linear model of the simulator. The Experimental results show that the simulator follows given coordinate well.

• 동력기계공학회지
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• 제10권3호
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• pp.97-103
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• 2006

In this study, a position trajectory tracking control algorithm is proposed for a pneumatic artificial muscle driving apparatus composed of a actuator which imitates the muscle of human, a position sensor and a control valve. The controller applied to the driving apparatus is composed of a state feedback controller and disturbance observer. The feedback controller which feeds back position, velocity and acceleration is derived from the linear model of pneumatic artificial muscle driving apparatus. The disturbance observer is designed to improve trajectory tracking performance and to reduce the effect of model discrepancy. The effectiveness of the designed controller is proved by experiments and the experimental results show that the pneumatic artificial muscle driving apparatus with the proposed control algorithm tracks given position reference inputs accurately.

• 한국안전학회지
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• 제15권3호
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• pp.115-123
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• 2000

공압구동기는 다양한 형태의 위험작업 환경하에서 사용되고 있다. 또한, 공압구동기를 적용한 공정은 일반적으로 환경친화적인 것으로 인식되고 있다. 대부분의 경우, 공압구동기는 point to point 제어에 사용된다. 그러나, 최근 공압구동기의 정밀 위치제어에 관한 많은 연구가 수행되고 있다. 본 연구에서는 비례밸브로 구성된 공압구동기의 추종위치제어에 관하여 논의한다. 제안되는 제어기는 압력제어 루프와 위치제어 루프로 구성된다. 공기의 압축성에 기인한 비선형성을 상쇄하기 위하여 되먹임선형화에 의한 PID제어기가 압력제어 루프에 사용된다. 위치제어에는 신경회로망을 사용하여 비선형성을 보상한 PID제어기가 사용된다. 실험결과에 의하면, 제안된 제어기는 공압구동기의 추종성능을 대폭 향상시킬 수 있는 것으로 나타났다.

• Ocean Systems Engineering
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• 제7권3호
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• pp.225-246
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• 2017

Excessive dynamic-tension variations on the top-tensioned risers (TTRs) deteriorate the structural integrity and cause potential safety hazards. This phenomenon has become more remarkable in the development of deep-water fields with harsher environmental loads. The conventional prediction method of tension variations in hydro-pneumatic tensioner (HPT) has the disadvantage to underestimate the magnitude of cyclic loads. The actual excessive dynamic tension variations are larger when considering the viscous frictional fluid effects. In this paper, a suppression method of tension variations in HPT is modeled by incorporating the magneto-rheological (MR) damper and linear-force actuator. The mathematical models of the combined HPT and MR damper are developed and a force-control scheme is introduced to compensate the excessive tension variations on the riser tensioner ring. Numerical simulations and analyses are conducted to evaluate the suppression of tension variations in HPT under both regular- and irregular-wave conditions for a drilling riser of a tensioned-leg platform (TLP). The results show that significant reduction of tension variations can be achieved by introducing the proposed system. This research has provided a theoretical foundation for the HPT tension control and related structural protection.

• 연구논문집
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• 통권28호
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• pp.73-87
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• 1998

A pneumatic control system of compressed air as a working fluid has a variety of advantages such as low price, high respondence, non-explosion and good control performance and thus has many applications in the field of automobile, electronic and semiconductor industry. However, it has a difficulty in contolling a precise position due to quick response of system and compressibility of working fluid and. in particular, shock stress may occur due to an external load, resulting in fracture of a cylinder cap unless cushion device is equipped in the linear actuator. To avoid this, a cushion device should be installed for damping effect of the external load and the supply pressure as well as for decreasing shock stress and vibration caused by high speed rotation. Previous studies include dimensionless analyses and computer simulations of cushion capability and experiments of horizontally-mounted cylinder performances. A new attempt is experimentally made in this study using a vertically-mounted cylinder under an operation condition of 4, 5 and 6 (bar) as supply pressure and 40, 70 and 100 (kgf) as external load. It turns out that the cushion pressure is mainly a function of the external load rather than the supply pressure. The cushion characteristics was also revealed in the meter-in circuit.

• Composites Research
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• 제27권2호
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• pp.47-51
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• 2014

본 논문은 기존의 유/공압 및 전기식 모터를 대체할 수 있는 경량, 고성능 지능소자 구동기를 설계/제작하고 이를 소형 무인비행체의 조종익 시스템에 적용 가능성을 연구한 것이다. 또한 압전 복합재료 작동기에 대한 성능평가를 수행하였으며, 유니모프 및 바이모프 형태의 작동기를 제작하여 각각의 작동 특성을 확인하였다. 이와 같은 성능시험 평과 결과를 통해 바이모프 형태의 작동기가 하중 유무와 무관하게 선형적인 받음각 변화를 가짐을 알 수 있었다. 이러한 지능소자 구동 시스템은 소형 로봇, 유도무기 및 MAV, UAV의 조종익 제어 시스템으로 사용될 수 있는 가능성을 확인하였다.