• International Journal of Fuzzy Logic and Intelligent Systems
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• 제5권2호
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• pp.124-130
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• 2005

Obstacle avoidance of underwater robots based on a modified virtual force field algorithm is proposed in this paper. The VFF(Virtual Force Field) algorithm, which is widely used in the field of mobile robots, is modified for application to the obstacle avoidance of underwater robots. This Modified Virtual Force Field(MVFF) algorithm using the fuzzy lgoc can be used in moving obstacles avoidance. A fuzzy algorithm is devised to handle various situations which can be faced during autonomous navigation of underwater robots. The proposed obstacle avoidance algorithm has ability to handle multiple moving obstacles. Results of simulation show that the proposed algorithm can be efficiently applied to obstacle avoidance of the underwater robots.

• 드라이브 ㆍ 컨트롤
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• 제12권2호
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• pp.14-20
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• 2015

This paper focuses on the issue of force synchronizing control for the injection servomechanism of injection molding machines. Prior to the controller design, a virtual design model was developed for the injection mechanism with an AC servomotor-ball screw. A synchronizing controller is designed and combined with the PID control to accommodate the mismatches between the real plant and the linear model plant used. Due to the plant uncertainty, the stiffness and the damping of the mechanism were considered. From the tracking control simulations based on the virtual design model, it is shown that a significant reduction in force synchronizing error is achieved through the use of a proposed control scheme.

• 한국정밀공학회지
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• 제18권11호
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• pp.80-85
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• 2001

In Part 2, dynamic cutting force model, thermal behavior model, and feed drive model are presented for development of a virtual machine tool. Some relevant results with brief descriptions for each model are presented to verify the proposed models. Experimental results for each model agreed well with the estimated ones. The developed models in this two-part paper are partially integrated as a comprehensive software environment.

• International Journal of Precision Engineering and Manufacturing
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• 제4권3호
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• pp.42-47
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• 2003

In Part 2 of this paper, the dynamic cutting force model, thermal behavior model, and feed drive model used in the development of a virtual machine tool (VMT) are briefly described. Some results are presented to verify the proposed models. Experimental data agreed well with the predicted results fer each model. A comprehensive software environment to integrate the models into a VMT is also proposed.

• 한국표면공학회지
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• 제39권2호
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• pp.64-69
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• 2006

Nanoscale task such as nanolithography and nanoindenting is a challenging work that is beyond the capabilities of human sensing and precision. Since surface forces and intermolecular forces dominate over gravitational and other more intuitive forces of the macro world at the nanoscale, a user is not familiar with these novel nanoforce effects. In order to overcome this scaling barrier, haptic interfaces that consist of visual and force feedback at the macro world have been used with an Atomic Force Microscope (AFM) as a manipulator at the nanoscale. In this paper, a nanoscale virtual coupling (NSVC) concept is introduced and the relationship between performance and impedance scaling factors of velocity (or position) and force are explicitly represented. Experiments have been performed for nanoindenting and nanolithography with different materials in the nanoscale virtual surface. The interaction forces (non contact and contact nanoforces) between the AFM tip and the nano sample are transmitted to the operator through the haptic interface.

• Journal of Mechanical Science and Technology
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• 제14권9호
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• pp.956-967
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• 2000

In this paper, we explore the issues of force display in the cooperative virtual environment shared by multiple users distributed over the network with heterogeneous hardware platforms. The proposed method is to cope with the problem of small time delay and the difference of sampling rate in the distributed configuration. In the proposed approach the interaction forces of the participants are just treated as the independent sources of acceleration. Thus the action of a participant simply changes the acceleration of the virtual object and consequently the states of the virtual object will be updated. When the updated states are reported to all the participants, the information on the time of state changes is delivered, too. Employing the discrete state information updated by the other users, each user modifies his own virtual environment and pseudo-realtime simulation can be realized. Excluding the software interface and the communication technique, it is proposed the simulation method for the operation of respective users and the way of calculating the driving input to the display device. For experimental verification we construct a cooperative virtual environment shared by two remote users and outline the results of experiments.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권6호
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• pp.287-293
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• 2005

Equations have been derived for computing electromagnetic forces by using the Continuum Design Sensitivity Analysis based on the Continuum Mechanics and the Virtual Work Principle. The resultant expressions have similar terms relating to the Korteweg-Holmholz force density, Maxwell Stress Tensor and Magnetic Charge Method but numerical implementation of the proposed scheme leads to efficient calculation and improved accuracy. In addition, the method can be easily applied to computing the magnetic force distribution as well as the global force. Results show the aforementioned advantages in comparison with the conventional methods.

• 드라이브 ㆍ 컨트롤
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• 제11권2호
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• pp.9-15
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• 2014

This paper deals with the issue of force synchronizing control for the clamping servomechanism of injection molding machines. Prior to the controller design, a virtual design model has been developed for the clamping mechanism with hydraulic systems. Then, a synchronizing controller is designed and combined with an adaptive feedforward control in order to accommodate the mismatches between the real plant and the linear model plant used. As a disturbance, the leakage due to the ring gap with relative motion in the cylinder has been introduced. From the robust force tracking simulations, it is shown that a significant reduction in the force synchronizing error is achieved through the use of a proposed control scheme.

• 한국지능시스템학회논문지
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• 제19권4호
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• pp.451-456
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• 2009

본 논문에서는 Virtual Mass-Spring-Damper 모델을 사용하여 이동로봇과 주위 물체와의 관계를 모델링하고 장애물의 충돌벡터를 검출하여 가상의 척력을 발생시키는 가상 임피던스 방법을 제안하였다. 이를 위하여 원격지 슬래이브 로봇의 주위 환경 정보 즉, 이동 로봇과 장애물과의 거리 및 접근 속도 등의 정보를 조작자에게 입체적으로 전달하기 위해 조이스틱의 각축에 연결된 모터를 이용하여 힘을 발생시킬 수 있도록 한다. 제안한 방법의 실제 로봇적용에 앞서 이동로봇의 장애물 회피 시뮬레이션을 통하여 알고리즘을 검증하였다.

• 로봇학회논문지
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• 제15권4호
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• pp.301-308
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• 2020

In this paper, we deal with the static modeling of a continuum robot that can perform surgical interventions. The proposed continuum robot is made of stainless steel wires and a multi lumen flexible tube using a thermoplastic elastomer. This continuum robot could be most severely deformed in physical contact with narrow external environments, when a lateral external force acts at the distal tip of the continuum robot. In order to predict the shape and displacement under the lateral external force loading, the forward kinematics, the statics modeling, the force-moment equilibrium equation, and the virtual work-energy method of the continuum robot are described. The deflection displacements were calculated using the virtual work-energy method, and the results were compared with the displacement obtained by the conventional cantilever beam theories. In conclusion, the proposed static modeling and the virtual work-energy method can be used in arrhythmia procedure simulations.