• Journal of Power System Engineering
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• v.19 no.3
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• pp.75-80
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• 2015

Typically, robot system configured by articulated robot manipulator with 1 DOF transfer unit is being applied in automotive manufacturing automation process. Especially, 1 DOF transfer unit is necessary to extend workspace of robot manipulator. In this configuration, because transfer unit works only one direction, robot manipulator only works in one side in case of car body painting or sealing automation process. it is necessary three robot manipulator system at least. In this paper, in order to robot manipulator works effectively in car body sealing automation application, we are suggested omni-directional manipulator system and conducted studying on redundancy resolution method to solve manipulability-optimal problem.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.1
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• pp.62-69
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• 2008

A specialized anthropomorphic robot hand which can be attached to the biped humanoid robot MAHRU-R in KIST, has been developed. This built-in type hand consists of three fingers and a thumb with total four DOF(Degrees of Freedom) where the finger mechanism is well designed for grasping typical objects stably in human's daily activities such as sphere and cylinder shaped objects. The restriction of possible motions and the limitation of grasping objects arising from the reduction of DOF can be overcome by reflecting a typical human finger's motion profile to the design procedure. As a result, the developed hand can imitate not only human hand's shape but also its motion in a compact and efficient manner. Also this novel robot hand can perform various human hand gestures naturally and grasp normal objects with both power and precision grasping capability.

• Journal of Biosystems Engineering
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• v.25 no.1
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• pp.63-70
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• 2000

In Korea, researches for year-round leaf vegetables production system are in progress and the most of them are focused on environment control. Automation technologies for harvesting , transporting and grading need to be developed. This study was conducted to develop harvesting process automation system profitable to a competitive price. 1. Manipulator and end-effector are to be designed and fabricated , and fuzzy logic controller for controlling these are to be composed. 2. The entire system constructed is to be evaluated through a performance test. A robot system for harvesting a lettuce was developed. It was composed of a manipulator with 20DOF (degrees of freedom) an end-effector, a lettuce feeding conveyor , an air blower , a machine vision device, 6 photoelectric sensors and a fuzzy logic controller. A fuzzy logic control was applied to determined appropriate grip force on lettuce. Leaf area index and height index were used as input parameters, and voltage was used as output parameter for the fuzzy logic controller . Success rate of the lettuce harvesting system was 93.06% , and average harvesting time was about 5 seconds per lettuce.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.1
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• pp.53-61
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• 2001

구조물이 과동한 기진력을 받을 때에 구조물의 진동 제어를 위하여 적응형 뱅뱅 제어 알고리듬이 저자들에 의해서 제안된 바 있으며, 이 제어 알고리듬을 1자유도계의 시험 구조물에 적용하여 제어 성능을 실험적으로 확인하였다. 본 논문은 이의 연장으로서 제안된 적응형 뱅뱅 제어 알고리듬을 최상층에 유압식 농동질량 감쇠기가 설치된 다자유도계의 시험 구조물에 적용하여 이의 유용성을 확인하였다. 이를 통하여 제안된 적응형 뱅뱅 제어 알고리듬은 제어 및 전체 구조계의 안전성이 보장되는 가운데 과도항 외부의 기진력을 받는 다자유도계의 구조물의 진동을 제어함에 효과적임을 확인할 수 있었다.

• International Journal of Aerospace System Engineering
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• v.3 no.2
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• pp.1-8
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• 2016

The improvements in high performance and agility of modern fighter aircraft have led to improvements in survivability as well. Related to these performance increases are rapid response and adequate deflection of the control surfaces. Most control surface failures result from the failure of the actuator. Therefore, the failure and behavior of the actuators are essential to both combat aircraft survivability and maneuverability. In this study, we investigate the effects of flaperon actuator failure on flight maneuvers of a supersonic aircraft. The flight maneuvers were analyzed using six degrees of freedom (6DOF) simulations. This research will contribute to improvements in the reconfiguration of control surfaces and control allocation in flight control algorithms. This paper compares the results of these 6DOF simulations with the horizontal tail actuator failures analyzed previously.

• Structural Engineering and Mechanics
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• v.43 no.1
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• pp.15-30
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• 2012

A damped Timoshenko beam element is introduced for the DOF-efficient forced vibration analysis of beam-like structures coated with viscoelastic damping layers. The rotary inertia as well as the shear deformation is considered, and the damping effect of viscoelastic layers is modeled as an imaginary loss factor in the complex shear modulus. A complex composite cross-section of structures is replaced with a homogeneous one by means of the transformed section approach in order to construct an equivalent single-layer finite element model capable of employing the standard $C^{0}$-continuity basis functions. The numerical reliability and the DOF-efficiency are explored through the comparative numerical experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.162-172
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• 2014

A three-dimensional dynamic model for simulating various motions of full vehicle is presented. The model has 16 independent degrees of freedom (DOF) consisting of three kinds of components; a vehicle body of 6 DOF, 4 independent suspensions equipped at every corner of the body, and 4 tire models linked with each suspension. The dynamic equations are represented in six coordinate frames such as world fixed coordinate, vehicle fixed coordinate, and four wheel fixed coordinate frames. Then these lead to the approximated prediction model of vehicle posture. Both lateral and longitudinal dynamics can be computed simultaneously under the conditions of which various inputs including steering command, driving torque, gravity, rolling resistance of tire, aerodynamic resistance, etc. are considered. It is shown through simulations that the proposed 3D model can be useful for precise design and performance analysis of any full vehicle control systems.

• Structural Engineering and Mechanics
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• v.57 no.1
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• pp.161-178
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• 2016

This research is aimed to design and analyze the performance of double dynamic vibration absorber (DVA) using a pendulum and a spring-mass type absorber for reducing vibration of two-DOF vibration system. The conventional fixed-points method and genetics algorithm (GA) optimization procedure are utilized in designing the optimal parameter of DVA. The frequency and damping ratio are optimized to determine the optimal absorber parameters. The simulation results show that GA optimization procedure is more effective in designing the double DVA in comparison to the fixed-points method. The experimental study is conducted to verify the numerical result.

• The Journal of Korea Robotics Society
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• v.18 no.1
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• pp.82-87
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• 2023

This paper proposes a disturbance observer-based control for 6-DOF remotely operated underwater vehicles with model uncertainties. The sum of external disturbance and the forces generated from model parameters except for the inertial matrix of the hydrodynamic model is defined as a lumped disturbance in this paper. Then, the lumped disturbance caused by model uncertainties and the external forces is estimated using the disturbance observer. Fortunately, the disturbance observer is constructed as a linear form because all the elements of the inertial matrix of the hydrodynamic model are constants. To verify the proposed control scheme, we show that the actual lumped disturbance is similar to the estimated lumped disturbance obtained by the disturbance observer. Finally, the position tracking performance in the disturbance environment is confirmed through the comparative study with a traditional inverse dynamics PD controller.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.8-15
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• 2024

This paper proposes a linear model predictive control of 6-DOF remotely operated underwater vehicles using nonlinear robust internal-loop compensator (NRIC). First, we design a integrator embedded linear model prediction controller for a linear nominal model, and then let the real model follow the values calculated through forward dynamics. This work is carried out through an NRIC and in this process, modeling errors and external disturbance are compensated. This concept is similar to disturbance observer-based control, but it has the difference that H_∞ optimality is guaranteed. Finally, tracking results at trajectory containing the velocity discontinuity point and the position tracking performance in the disturbance environment is confirmed through the comparative study with a traditional inverse dynamics PD controller.