• 한국산학기술학회논문지
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• 제19권12호
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• pp.47-53
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• 2018

산업용으로 다양한 형태의 로봇팔이 사용되고 있으며, 특히, 다품종 소량생산으로 생산방식의 변화가 이루어지면서 산업현장에서 다양하게 사용이 가능한 그리퍼에 대한 중요성이 높아지고 있다. 이러한 중요성에 기반을 두어 본 연구진은 기존에 연성재질의 비선형성을 이용하여 강성을 변화시킬 수 있는 가변강성 메커니즘 그리퍼를 연구하였다. 시제품을 제작하고 실험을 통해 강성의 변화와 그 유용성을 확인하였다. 그러나 세 개의 가변강성 메커니즘을 배치하여 그리퍼를 설계 및 제작함으로써 물체를 파지하는 상황에 따라 파지를 제대로 하지 못하는 현상이 발생하였다. 또한, 그리퍼 간의 균형이 맞지 않아 물체 파지 시에 파지할 물체가 회전하면서 미끄러지는 경우가 드물게 발생하는 문제가 있었다. 이러한 문제점을 보완하기 위하여 새로운 형태의 그리퍼가 필요하게 되었다. 새로운 형태의 그리퍼를 설계하기 위하여 생체모사기술을 적용하였다. 사람의 손바닥과 파리지옥의 움직임을 통해 영감을 얻어 새롭게 가변강성 소프트 로봇 핸드를 설계하였다. 손바닥이 접히는 메커니즘을 가변강성 그리퍼에 장착된 텐던을 당기는 것과 연동하여 파지 성능을 높일 수 있었다. 가변강성 메커니즘에 파리지옥과 손바닥 형태의 메커니즘을 결합하여 파지 안전성을 높인 소프트 로봇 핸드는 기존의 가변강성 메커니즘 그리퍼보다 다양한 형태와 무게를 가진 물체를 안정적으로 파지하였다.

• 제어로봇시스템학회논문지
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• 제20권3호
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• pp.345-355
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• 2014

Since the beginning of the 21st century, emergence of innovative technologies in robotic and telepresence surgery has revolutionized minimally access surgery and continually has advanced them till recent years. One of such surgeries is endoscopic surgery, in which endoscope and endoscopic instruments are inserted into the body through small incision or natural openings, surgical operations being carried out by a laparoscopic procedure. Due to a vast amount of developments in this technology, this review article describes only a technological state-of-the arts and trend of endoscopic robots, being further limited to the aspects of key components, their functional requirements and operational procedure in surgery. In particular, it first describes technological limitations in developments of key components and then focuses on the description of the performance required for their functions, which include position control, tracking, navigation, and manipulation of the flexible endoscope body and its end effector as well, and so on. In spite of these rapid developments in functional components, endoscopic surgical robots should be much smaller, less expensive, easier to operate, and should seamlessly integrate emerging technologies for their intelligent vision and dexterous hands not only from the points of the view of surgical, ergonomic but also from safety. We believe that in these respects a medical robotic technology related to endoscopic surgery continues to be revolutionized in the near future, sufficient enough to replace almost all kinds of current endoscopic surgery. This issue remains to be addressed elsewhere in some other review articles.

• 제어로봇시스템학회논문지
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• 제22권10호
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• pp.853-858
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• 2016

Cooperation and collaboration with robots are key functions of robotic utility that are currently developing. Thus, robots should be safe and resemble human beings to cope with these needs. In particular, dual-arm robots that mimic human kinetics are becoming the focus of recent industrial robotics research. Their size is similar to the size of a human adult; however, they lack natural, human-like motion. One of the critical reasons for this is the shoulder complex. Most recent dual-arm robots have only 2 degrees of freedoms (DOFs), which significantly limits the workspace and mobility of the shoulders and arms. Therefore, a redundant shoulder complex could be very important in new developments that enable new capabilities. However, constructing a kinematically redundant shoulder complex is difficult because of spatial constraints. Therefore, we propose a novel, redundant shoulder complex for a human-like robot that is driven by flexible wire tendons. This kinematically redundant shoulder complex allows human-like robots to move more naturally because of redundant DOFs. To control the proposed shoulder complex, a hybrid control scheme is used. The positioning precision has also been considered, and the ability of the shoulder complex to perform several human-like motions has been verified.

• 융합신호처리학회논문지
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• 제15권3호
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• pp.104-111
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• 2014

이 논문에서는 자동차의 제동장치에 사용되는 브레이크 모듈 조립 작업을 로봇을 사용하여 자동화한 사례를 소개한다. 브레이크 모듈은 하나의 토크 멤버에 두 개의 브레이크 패드와 두 개의 패드 라이너를 장착하여 조립을 완성한다. 이 조립 작업은 로봇의 방향을 자주 바꾸어 주어야하기 때문에 일반적인 산업용 로봇 핸드를 사용하면 조립 시간이 오래 걸린다. 이 논문에서는 두 가지 방법을 제안한다. 첫 번째 방법은 다섯 개의 그리퍼를 갖는 로봇 엔드 이펙터를 설계, 제작하여 기존의 산업용 6축 머니퓰레이터에 장착하여 조립 작업을 수행하는 방법이다. 이 방법에서는 두 개의 브레이크 패드와 두 개의 패드 라이너를 한꺼번에 파지하여 조립 작업을 수행하며 따라서 하나의 그리퍼 만을 가지고 있는 기존의 엔드 이펙터에 비해 조립 시간을 줄일 수 있었다. 두 번째 방법에서는 첫 번째 방법을 더욱 개선하여 엔드 이펙터가 하나의 부가적인 자유도를 가지도록 설계, 제작하여 기존의 산업용 6축 머니퓰레이터에 장착하였다. 이 방법에서는 전체 로봇 머니퓰레이터가 7 자유도를 갖는 여유자유도 머니퓰레이터가 되어 로봇의 동작을 최소화하면서 조립에 필요한 다양한 로봇 방향을 구현할 수 있었다.

• Journal of Mechanical Science and Technology
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• 제16권12호
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• pp.1633-1642
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• 2002

Uninterrupted power supply has become indispensable during the maintenance task of active electric power lines as a result of today's highly information-oriented society and increasing demand of electric utilities. The maintenance task has the risk of electric shock and the danger of falling from high place. Therefore it is necessary to realize an autonomous robot system using electro-hydraulic manipulator because hydraulic manipulators have the advantage of electric insulation. Meanwhile it is relatively difficult to realize autonomous assembly tasks particularly in the case of manipulating flexible objects such as electric lines. In this report, a discrete event control system is introduced for automatic assembly task of electric lines into sleeves as one of the typical task of active electric power lines. In the implementation of a discrete event control system, LVQNN (linear vector quantization neural network) is applied to the insertion task of electric lines to sleeves. In order to apply these proposed control system to the unknown environment, virtual learning data for LVQNN is generated by fuzzy inference. By the experimental results of two types of electric lines and sleeves, these proposed discrete event control and neural network learning algorithm are confirmed very effective to the insertion tasks of electric lines to sleeves as a typical task of active electric power maintenance tasks.

• 제어로봇시스템학회논문지
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• 제20권8호
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• pp.835-841
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• 2014

In this paper we propose a swing-up strategy for a single inverted pendulum. The proposed method has a feature whereby can handle the input and output constraint of a pendulum in a systematic way. For the swing-up of a pendulum, we adopt a 2-DOF control structure that combines the feedforward and feedback control. In order to generate the swing-up feedforward trajectories that satisfy the input and output constraint, we formulate the problem of generating feedforward trajectories as a nonlinear optimal control problem subject to constraints. We illustrate that the proposed method is more flexible than the existing method and provides great freedom in choosing the actuator of the inverted pendulum. Through an experiment, we show that the proposed method can swing a pendulum upward effectively while satisfying all the imposed constraints.

• 한국지능시스템학회논문지
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• 제15권2호
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• pp.185-190
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• 2005

본 논문은 파리미터의 불확실성을 포함하는 Takagi-Sugeno(T-S) 퍼지 시스템을 위한 체계적인 출력 추종 제어기 설계기법을 제안한다. 불확실 T-S 퍼지 시스템은 효과적인 설계를 위하여 퍼지 입력 공간의 발화도의 우세성에 따르는 몇 개의 불확실 선형 시스템으로 표현된다. 출력 추종 제어 오차는 일반화된 리아푸노프 함수에 의하여 해석된다. 이에 따라 출력 추종 제어기 설계 문제는 몇 개의 불확실 선형 시스템의 안정화 문제로 변환된다. 강인 추종 제어기 설계 조건은 선형행렬 부등식의 형태로 유도된다. 마지막으로 파라미터 불확실성을 포함하는 혼돈 로렌Cm 카오스 시스템의 출력 추종 문제를 고려하여 본 논문에서 제안한 기법의 효용성을 입증한다.

• International Journal of Control, Automation, and Systems
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• 제1권4호
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• pp.474-483
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• 2003

Belt drives provide freedom to position the motor relative to the load and this phenomenon enables reduction of the robot arm inertia. It also facilitates quick response when employed in robotics. Unfortunately, the flexible dynamics deteriorates the positioning accuracy. Therefore, there exists a trade-off between the simplicity of the control strategy to reject time varying disturbance caused by flexibility of the belt and precision in performance. Resonance of the system further leads to vibrations and poor accuracy in positioning. In this paper, accurate positioning of a belt driven mechanism using a feed-forward compensator under maximum acceleration and velocity constraints is proposed. The proposed method plans the desired trajectory and modifies it to compensate delay dynamics and vibration. Being an offline method, the proposed method could be easily and effectively adopted to the existing systems without any modification of the hardware setup. The effectiveness of the proposed method was proven by experiments carried out with an actual belt driven system. The accuracy of the simulation study based on numerical methods was also verified with the analytical solutions derived.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.963-968
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• 1990

An iterative learning control scheme for tracking control of a class of uncertain nonlinear systems is presented. By introducing a model reference adaptive controller in the learning control structure, it is possible to achieve zero tracking of unknown system even when the upperbound of uncertainty in system dynamics is not known apriori. The adaptive controller pull the state of the system to the state of reference model via control gain adaptation at each iteration, while the learning controller attracts the model state to the desired one by synthesizing a suitable control input along with iteration numbers. In the controller role transition from the adaptive to the learning controller takes place in gradually as learning proceeds. Another feature of this control scheme is that robustness to bounded input disturbances is guaranteed by the linear controller in the feedback loop of the learning control scheme. In addition, since the proposed controller does not require any knowledge of the dynamic parameters of the system, it is flexible under uncertain environments. With these facts, computational easiness makes the learning scheme more feasible. Computer simulation results for the dynamic control of a two-axis robot manipulator shows a good performance of the scheme in relatively high speed operation of trajectory tracking.

• 제어로봇시스템학회논문지
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• 제16권2호
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• pp.164-171
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• 2010

We have studied the port-automation system which is requested by the steep increment of cost and complexity for processing the freight. This paper will introduce a new algorithm for navigating and controlling the autonomous Guided Vehicle (AGV). The camera has the optical distortion in nature and is sensitive to the external ray, the weather, and the shadow, but it is very cheap and flexible to make and construct the automation system for the port. So we tried to apply to the AGV for detecting and tracking the lane using the CCD camera. In order to make the error stable and exact, this paper proposes new concept and algorithm for obtaining the error is generated by the Virtual Photo-Sensor Array (VPSA). VPSAs are implemented by programming and very easy to use for the various autonomous systems. Because the load of the computation is light, the AGV utilizes the maximal performance of the CCD camera and enables the CPU to take multi-tasks. We experimented on the proposed algorithm using the mobile robot and confirmed the stable and exact performance for tracking the lane.