• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.392-395
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• 1995

This paper presents a time efficient method for determining a sequence of locations of a mobile manipulator that facilitates tracking of continuous path in cluttered environment. Given the task trajectory in the form of octree data structure, the algorithm performs characterization of task space and subsequent multistage optimization process to determine task feasible locations of the robot. Firstly, the collision free portion of the trajectory is determined and classified according to uniqueness domains of the inverse kinematics solutions. Then by implementing the extent of task feasible subspace into an optimization criteria, a multistage optimization problem is formulated to determines the task feasible locations of the mobile manipulator. The effectiveness of the proposed method is shown through a simulation study performed for a 3-d.o.f. manipulator with generic kinematic structure.

• ICROS
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• v.2 no.3
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• pp.81-91
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• 1996

이 글에서는 Multi-Tasking Real Time O.S인 VxWorks를 기본으로 하여 다중센서 융합(Multi-Sensor Fusion) 능력을 갖는 다중 로봇 협조제어 시스템의 구현에 대하여 살펴보았다. 본 제어 시스템은 두대 로봇의 제어에 필요한 장애물 회피, 조건 동작(Conditional Motion) 혹은 동시동작(Concurrent Motion)과 외부 디바이스와의 동기 Motion(Conveyor Tracking)을 수행할 수 있게 구현하였고, 몇몇 작업을 통해 우수성을 입증하였다. 앞으로 본 연구와 관련한 추후 과제로는 1) 자유도가 6관절형인 수직다관절 매니퓰레이터를 위한 충돌회피 알고리즘의 개발, 2) Two Arm Robot의 상대 위치를 위한 Auto-Calibration 시스템의 개발, 3) CAD Based Trajectory 생성 등이 있다.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.705-710
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• 1989

A practical method of identifying the inertial parameters, viscous friction and Coulomb friction of a robot is presented. The parameters in the dynamic equations of a robot are obtained from the measurements of the command voltage and the joint position of the robot. First, a dynamic model of the integrated motor and manipulator is derived. An off line parameter identification procedure is developed and applied to the University of Minnesota Direct Drive Robot. To evaluate the accuracy of the parameters the dynamic tracking of robot was tested. The trajectory errors were significantly reduced when the identified dynamic parameters were used.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1519-1520
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• 2008

이 논문에서는 이동로봇의 경로추적문제를 다항 퍼지 모델로 나타내고 SOSTOOL을 이용하여 해결하고자 한다. 제안하는 방법은 기존의 LMI을 사용한 방법과 비교하여 작은 제어입력과 이동로봇이 주어진 경로를 쫓아감에 있어 매끄러운 결과를 나타냄을 알 수 있다. 본 논문에서는 이동로봇 기구학을 시스템의 안정성 문제로 변형하고 이를 퍼지모델로 구성하여 SOSTOOL을 사용하여 제어입력을 구하고 모의실험을 통해 그 결과를 검증하도록 한다.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.65-68
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• 1996

Robotic manipulators have become increasingly important in the field of flexible automation. High speed and high-precision trajectory tracking are indispensable capabilities for their versatile application. The need to meet demanding control requirement in increasingly complex dynamical control systems under significant uncertainties, leads toward design of intelligent manipulation robots. This paper presents a new approach to the design of neural control system using digital signal processors in order to improve the precision and robustness. The TMS32OC31 is used in implementing real time neural control to provide an enhanced motion control for robotic manipulators. In this control scheme, the networks introduced are neural nets with dynamic neurons, whose dynamics are distributed over all the, network nodes. The nets are trained by the distributed dynamic back propagation algorithm. The proposed neural network control scheme is simple in structure, fast in computation, and suitable for implementation of real-time, control. Performance of the neural controller is illustrated by simulation and experimental results for a SCARA robot.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.12
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• pp.1286-1293
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• 2008

This paper proposes a realization of robust trajectory tracking for an industrial robot by using PD-sliding mode hybrid control. The PD control has a good performance in the transient period while the sliding mode control has robustness against the system uncertainties. The proposed control method is proposed for the control of a multi-joint robot by taking advantages of both the PD and sliding mode controls. The embodiment of distributed controllers that drive 4-DOF axes has evaluated through experiments with the multi-joint robot AT1. The PD-sliding mode algorithm which is proposed in this paper shows a good performance in the transient period and robustness against disturbances and This paper shows accuracy of end-effector.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.4-4
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• 2000

In this paper, the backstepping control method that is useful for cascade systems is applied to the slew maneuver of the spacecraft. The quaternion is used for representing the attitude of the spacecraft, because the reference trajectory of angular velocity has simple mathematical form. The conventional backstepping control has severa] problems such as slow convergence, trivial cancelling of nonlinear terms, and excessive control input. To overcome these problems, the modified backstepping control method which is redesign of Lyapunov function is proposed. To design a tracking function for angular velocity, it is necessary to estimate the process of maximum angular velocity, and therefore the estimation procedure using Bellman-Gronwall inequality is developed. To verify the effectiveness of the proposed control law, numerical simulation is performed and the results are compared with the exiting control scheme.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.3
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• pp.207-214
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• 2010

This paper proposes about decentralized control approach based Leader-Follower formation control using LOS (Line of Sight) algorithm and unknown input observer. The position of robots which is a basic information in multi-robot or single robot motion control is determined by localization algorithm fusing UPS (Ultrasonic Position System) and kinematics model. For formation control, a decentralized control approach individually installing a local controller in leader and follower robot is adopted. Leader robot is controlled to track a specified trajectory by LOS algorithm, and the other robots follow the leader by local controller based on tracking platoon level function, self-sensing data and estimated information from unknown input observer. The performance of proposed method is proven through the formation experiment of two vehicle models.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.481-491
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• 2015

Since the crack in the surface of the concrete acts as the main reason influencing the life span of the structure, regular inspections and maintenance are required. The sealing required for maintenance of the concrete surface is a method of repairing the crack in the surface in the beginning, and is effective in preventing additional cracks and expansion that occurs with time. However, sealing on large sized structures such as tall buildings or bottom parts of bridges are difficult to ensure safety of the workers due to inadequate working environments. Due to this reason, the importance of the need for sealing automation for the maintenance of large sized concrete structures is emerging. This study proposes two control methods to apply robot systems to the sealing of cracks on the bottom parts of concrete bridges. First is the method of automatically tracking the trajectory of cracks. The robot gets the trajectory of the cracks using video information obtained from cameras. Comparing the previous several points and new point, the next point can be estimated. Thus, the trajectory of the crack can be tracked automatically. The other method is sealing by maintaining steady force to the contacting surface. The concrete surface exposed to an external environment for a long time gets an irregular roughness. If robots are able to carry out sealing while maintaining a steady contact force on these rough surfaces, complete equal sealing can be maintained. In order to maintain this equal force, a force control method using impedance is proposed. This paper introduces two developed control methods to apply to sealing robots, and conducts a Lab Test and Field Test after applying to a robot. Based on the test results, opinions on the possibilities of field application of the robot applied with the control methods are presented.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.90-98
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• 2015

This research propose with image-based visual a new approach to design a feedback control of mobile robot. because mobile robot must be recharged periodically, it is necessary to detect and move to docking station. Generally, laser scanner is used for detect of position of docking station. CCD Camera is also used for this purpose. In case of using camera, the position-based visual servoing method is widely used. But position-based visual servoing method requires the accurate calibration and it is hard and complex work. Another method using cameras is inmage-based visual feedback. Recently, image based visual feedback is widely used for robotic application. But it has a problem that cannot have linear trajectory in the 3-dimensional space. Because of this weak point, image-based visual servoing has a limit for real application. in case of 2-dimensional movement on the plane, it has also similar problem. In order to solve this problem, we point out the main reason of the problem of the resolved rate control method that has been generally used in the image-based visual servoing and we propose an image-based visual feedback method that can reduce the curved trajectory of mobile robot in th cartesian space.