• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.5
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• pp.455-461
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• 1999

In this paper, we present the 3DOF force-rei1ecting interface which allows to acquire force of objc'Ct within a a virtual environment. This system is comlxlsed of device, virtual environment model, and force-rei1ecting r rendering algorithm. We design a J DOF force reflecting device using the pc$\alpha$allel linkage, torque shared by W wire, and the controller of system applied by impedance control algorithm. The force reflecting behaviour i implemented as a function position is equivalent to controlling the mechanical impedance felt by the user. E Especially how force should be supplied to user, we know using a God-Object algorithm As we experiment a system implement$\varepsilon$d by the interface of 3D virtual object and 3DOF force reJll'Cting i interface, we can feel a contact, non contact of :)D virtual object surface and sensin앙 of push button model.utton model.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.3
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• pp.321-328
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• 1998

When we control the level of the steam generator in the nuclear power plants, a swell and shrink arises from many disturbances such as feed water rate, feed water temperature, main steam flow rate, and coolant temperature. If we use the conventional type of PI controller in this system, we will not have stability during controlling at lower power, the removal function of disturbances, and a load follow-up control effectively. In this paper, we study the application of a 2-Degree of Freedom(2-DOF) PID controller to the level control of the steam. generator of nuclear power plants through the simulation and the experimental steam generator. We use the parameters $\alpha$, $\beta$, $\gamma$ of the 2-DOF PID controller for the removal of disturbances and the parameters Kp,Ti,Td of the conventional type of PID controller for controlling setpoint. The back-propagation learning algorithm of neural network is used for tuning the 2-DOF PID controller. We can find satisfactory results of the removal of the disturbances and the tracking function in the change of setpoint through the simulation and experimental steam generator.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.10
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• pp.1031-1039
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• 2013

This paper presents gain optimization of a 6-DOF underwater robotic platform with 4 rotatable thrusters. To stabilize the 6-DOF motion of the underwater robotic platform, a back-stepping controller is designed with 6 proportional gains and 6 derivative gains. The 12 gains of the backstepping controller are optimized to decrease settling time in step response in 6-DOF motion independently. Stability criterion and overshoots are used as a constraint of the optimization problem. Trust-region algorithm and hybrid Taguchi-Random order Coordinate search algorithm are used to determine the optimal parameters, and the results by two methods are analyzed. Additionally, the resulting controller shows improved performance under disturbances.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.260-262
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• 2020

본 논문은 6DOF 위치기반 자기장 센서(Liverty Latus, Pollhemus)를 사용한 가상현실 방송제작에서 사용할 수 있는 인터랙티브 증강현실 시스템, K-Pointer를 제안한다. 우리는 방송에서 추적 및 인식의 정확성을 높이기 위해 Pollemus사의 6DOF 자기장기반 위치 추적 센서 리버티(수신부,소스)와 라투스(송신부,마커), 그리고 4입력 버튼장치를 결합한 인터페이스를 가지고 기존 방송용 증강현실 시스템과 통합하여 새로운 인터랙티브 증강현실 시스템을 개발하였다. 본 시스템은 방송용 증강현실 그래픽 합성 시스템(수신부)과 센서의 위치정보와 버튼 이벤트를 전송하는 시스템(송신부)으로 구성되며, 센서추적정보와 버튼이벤트 정보는 UDP로 실시간으로 수신부로 전송된다. 우리는 사용자 손의 모션과 버튼이벤트로 그래픽 정보를 인터랙티브하게 제어할 수 있게 하였다. 결과적으로 본 시스템은 기존의 합성중심의 방송용 증강현실 시스템을 사용자의 모션 기반 그래픽을 제어할 수 있는 인터랙티브 증강현실시스템으로 그 기능을 확장 시킬 수 있게 한다. 제안된 시스템은 광학식 추적을 하지 않기 때문에 조명의 변화에 영향이 없으며, 라투스 수신기가 작기 때문에 손에 쥐었을 때 거의 보이지 않고 가려도 추적이 강인하여 버튼장치를 통해 사용자가 정확한 이벤트로 직접 그래픽을 그리거나 쉽게 제어할 수 있는 장점이 있다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.1
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• pp.41-48
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• 2013

In this work, 4-DOF ER haptic master is proposed and integrated with a slave robot for minimally invasive surgery(MIS). Using a controllable ER fluid, the haptic master can generate a repulsive force/torque with the 4-DOF motion. For realization of master-slave robot system, the motion command of the haptic master is realized by slave surgery robot. In order to follow the 4-DOF motion of the haptic master, novel mechanism of slave surgery robot with gimbal joint is devised. Accordingly, the haptic master-slave robot system is established by incorporating the slave robot with the haptic master device in which the desired repulsive force/torque and position are transferred to each other via wireless communications. In order to obtain the desired force/torque and position trajectories, tracking controllers for haptic master and slave robot are designed and implemented, respectively. It has been demonstrated that the desired effective torque tracking control performance is well achieved using the proposed haptic master-slave robot system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.421-427
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• 2012

In this work, 4 DOF ER haptic master is proposed and integrated with a slave robot for minimally invasive surgery (MIS). Using a controllable ER fluid, the haptic master can generate a repulsive force/torque with the 4-DOF motion. For realization of master-slave robot system, the motion command of the haptic master is realized by slave surgery robot. In order to follow the 4 DOF motion of the haptic master, novel mechanism of slave surgery robot with gimbal joint is devised. Accordingly, the haptic master-slave robot system is established by incorporating the slave robot with the haptic master device in which the desired repulsive force/torque and position are transferred to each other via wireless communications. In order to obtain the desired force/torque and position trajectories, tracking controllers for haptic master and slave robot are designed and implemented, respectively. It has been demonstrated that the desired effective torque tracking control performance is well achieved using the proposed haptic master-slave robot system.

• International Journal of Control, Automation, and Systems
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• v.4 no.2
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• pp.227-235
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• 2006

For a sophisticated humanoid that explores and learns its environment and interacts with humans, anthropomorphic physical behavior is much desired. The human vision system orients each eye with three-degree-of-freedom (3-DOF) in the directions of horizontal, vertical and torsional axes. Thus, in order to accurately replicate human vision system, it is imperative to have a simulator with 3-DOF end-effector. We present a 3-DOF anthropomorphic oculomotor system that reproduces realistic human eye movements for human-sized humanoid applications. The parallel link architecture of the oculomotor system is sized and designed to match the performance capabilities of the human vision. In this paper, a biologically-inspired mechanical design and the structural kinematics of the prototype are described in detail. The motility of the prototype in each axis of rotation was replicated through computer simulation, while performance tests comparable to human eye movements were recorded.

• Journal of Mechanical Science and Technology
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• v.18 no.4
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• pp.535-549
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• 2004

This paper proposes a sliding mode controller with fuzzy adaptive perturbation compensator(FAPC) to get a good control performance and reduce the chatter, The proposed algorithm can reduce the chattering because the proposed fuzzy adaptive perturbation compensator compensates the perturbation terms. The compensator computes the control input for compensating unmodeled dynamic terms and disturbance by using the observer-based fuzzy adaptive network(FAN) The weighting parameters of the compensate. are updated by on-line adaptive scheme in order to minimize the estimation error and the estimation velocity error of each actuator. Therefore, the combination of sliding mode control and fuzzy adaptive network gives the robust and intelligent routine to get a good control performance. To evaluate the control performance of the proposed approach, tracking control is experimentally carried out for the hydraulic motion platform which consists of a 6-DOF parallel manipulator.

• Journal of Biosystems Engineering
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• v.25 no.2
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• pp.141-150
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• 2000

This study was carried out to de develop a control strategy of a fruit harvesting redundant robot. The method of generating a safe trajectory, which avoids collisions with obstracles such as branches or immature fruits, in the 3D(3-dimension) space using artificial potential field technique and virtual plane concept was proposed. Also, the method of setting reference velocity vectors to follow the trajectory and to avoid obstacles in the 3D space was proposed. Developed methods were verified with computer simulations and with actual robot tests. Fro the actual robot tests, a machine vision system was used for detecting fruits and obstacles, Results showed that developed control method could reduce the occurrences of the robot manipulator located in the possible collision distance. with 10 virtual obstacles generated randomly in the 3 D space, maximum rates of the occurrences of the robot manipulator located in the possible collision distance, 0.03 m, from the obstacles were 8 % with 5 degree of freedom (DOF), 8 % with 6-DOF, and 4% with 7-DOF, respectively.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.84.4-84
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• 2002

$\textbullet$ To achieve 3 high power-to-weight ratio, design of 3DOF hip module $\textbullet$ Using parallel mechanism and linear actuator consist of a ball-screw mechanism $\textbullet$ The kinematics analysis for the hip module $\textbullet$ A kinematic index to measure actuator power are introduced. $\textbullet$ It is demonstrated throught simulation that incorporation of redu ndant actuator into the hip module