• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.407-409
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• 1996

The Direct Arm(DDA) is a SCARA typed direct drive manipulator with three degree of freedom(DOF) using the direct motor of the NSK company. In the paper, we propose a convenient interface for the SCARA-type robot which is practical to use. The proposed Visual Robot Teaching Mode using 3D graphics replaces the current teaching box. And besides this graphical teaching software can be implemented on the PC which is company used as a robot controller. This program was developed for the Windows 95 OS.

• Smart Structures and Systems
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• v.20 no.4
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• pp.397-413
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• 2017

Precast concrete (PC) members are currently being employed for general construction or partial replacement to reduce construction period. As assembly work in PC construction requires connecting PC members accurately, measuring the 6-DOF (degree of freedom) relative displacement is essential. Multiple planar markers and camera-based displacement measurement systems can monitor the 6-DOF relative displacement of PC members. Conventional methods, such as direct linear transformation (DLT) for homography estimation, which are applied to calculate the 6-DOF relative displacement between the camera and marker, have several major problems. One of the problems is that when the marker is partially hidden, the DLT method cannot be applied to calculate the 6-DOF relative displacement. In addition, when the images of markers are blurred, error increases with the DLT method which is employed for its estimation. To solve these problems, a hybrid method, which combines the advantages of the DLT and MCL (Monte Carlo localization) methods, is proposed. The method evaluates the 6-DOF relative displacement more accurately compared to when either the DLT or MCL is used alone. Each subsystem captures an image of a marker and extracts its subpixel coordinates, and then the data are transferred to a main system via a wireless communication network. In the main system, the data from each subsystem are used for 3D visualization. Thereafter, the real-time movements of the PC members are displayed on a tablet PC. To prove the feasibility, the hybrid method is compared with the DLT method and MCL in real experiments.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.965-970
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• 2015

This paper uses response surface methodology as the optimization method of torque of multi-DOF deflection type PM motor. Firstly, the application of Taguchi algorithm selects structural parameters affecting the motor torque largely which simplifies the optimization process greatly. Then, based on the central composite design (CCD), response surface equation numerical model is constructed by the finite element method. With the aid of experiment design and analysis software, the effects of the interaction among factors on the index are analyzed. The results show that the analytical method is efficient and reliable and the experimental results can be predicted by response surface functions.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.2
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• pp.48-56
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• 2001

This paper presents the position tracking control of a closed-loop cylinder system using electro-rheological (ER) valve actuators. After manufacturing three sets of cylindrical ER valves on the basis of Bingham model of ER fluid, a 3 dof(degree-freedom) closed-loop cylinder system having the heave, roll and pitch motions is constructed. The governing equations of motion are derived using Lagrange's equation and a control model is formulated by considering nonlinear characteristics of the system, Sliding mode controllers are the designed for these ER valve actuators in order to achieve position tracking control. The effectiveness of trajectory tracking control performance of the proposed cylinder system is demonstrated through computer simulation and experimental implementation of the sliding mode controller.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.197-203
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• 2005

This paper presents kinematic calibration of parallel manipulators with partial pose measurements using a device that measures a rotation of the end-effector along with its position. The device contains an LVDT, a biaxial inclinometer, and a rotary sensor and facilitates automation of the measurement procedure. The device is designed in a modular fashion and links of different lengths can be used. The additional kinematic parameters required for the measurement device are discussed, kinematic relations are derived, and cost function is established to perform calibration with the proposed device. The study is performed for a six degree-of-freedom(DOF) fully parallel HexaSlide Mechanism(HSM). Experimental results show significant improvement in the accuracy of the HSM.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.3
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• pp.165-173
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• 2000

This Paper presents the position tracking control of a closed-loop cylinder system using electro-rheological(ER) valve actuators. After manufacturing three sets of cylindrical ER valves on the basis of Bingham model of ER fluid, a 3 dof(degree-of-freedom) closed-loop cylinder system having the heave, roll and pitch motions is constructed. The governing equations of motion are derived using Lagrange's equation and a control model is formulated by considering nonlinear characteristics of the system. Sliding mode controllers are then designed fer these ER valve actuators in order to achieve position tracking control. The effectiveness of trajectory tracking control performance of the proposed cylinder system is demonstrated through computer simulation and experimental implementation of the sliding mode controller.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.354-362
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• 2000

In Korea, researches on year-round leaf vegetables production system are in progress, most of them focused on environmental control. Therefore, automation technologies for harvesting, transporting, and grading are in great demand. A robot system for harvesting lettuces, composed of a 3-DOF (degree of freedom) manipulator, an end-effector, a lettuce feeding conveyor, an air blower, a machine vision system, six photoelectric sensors, and a fuzzy logic controller, was developed. A fuzzy logic control was applied to determine appropriate grip force on lettuce. Leaf area index and height were used as input variables and voltage as an output variable for the fuzzy logic controller. Success rate of the lettuce harvesting was 94.12%, and average harvesting time was approximately 5 seconds per lettuce.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.12
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• pp.66-72
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• 2001

In this paper, by using pseudo-inverse matrix of the spatial redundant flexible manipulators, a position control method and its effect in vibration suppression was presented. Vibration suppression control was developed using lumped mass spring model of the flexible manipulators. With 2 elastic links and 7 rotory joint manipulator ADAM, (1)position control for no redundancy, and (2)position control for one redundant DOF(degree of freedom) were tested. The objective of this experiment is to show the effect of position control, using pseudo-inverse matrix. toward the improvement of operation, and at the same time, to reduce the vibration of the link and the magnitude of the joint torque.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.90-94
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• 2004

Among various modern control theories, PID control has been well used for several decades. PID algorithms needs son tuning methods are used for selecting PID parameters. But in some cases various kinds of performance indices are used instead of well-known tuning rules, and so variable type of performance index must be tested so that controllers, output characteristics and disturbance rejection property meets some specifications. In this paper, linear conbinational type of performance using error signal, time, control input and robustness is used to the PID control of air conditioning system. By the 2 DOF PID parmeters minimizing perfromacne index, controllers, output characteristics and robustness properties are analyzed. Simulations are done with MATLAB m file and mdl files.

• Proceedings of the KIEE Conference
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• 1999.07g
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• pp.3073-3076
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• 1999

In this paper, $H_{\infty}$ two-degree-of freedom(2-DOF) model following control method is applied for the control of a brushless servo motor to achieve high robust performance. The proposed robust control algorithm designed to meet the robust stability and performances present that the robust control method is superior to conventional control methods in controlling the speed and position of a servo motor. The designed controller is implemented as an outer loop controller to a factory designed motor-servopack system. It is illustrated by simulations that the proposed method is effective to control servo systems.