• Journal of the Korea Institute of Military Science and Technology
• /
• v.20 no.5
• /
• pp.647-653
• /
• 2017

In this paper, we deal with the experimental verification of 1D virtual force field algorithm based reflexive local path planning on uneven and dusty environment. The existing obstacle detection method on uneven and dusty environment and 1D virtual force field based reflexive local path planning algorithm simply are introduced. Although the 1D virtual force field algorithm is verified by various simulations, additional efforts are needed to verify this algorithm in the real-world. The introduced methods are combined with each other, installed to real mobile platforms and verified by various real experiments.

• Science of Emotion and Sensibility
• /
• v.5 no.1
• /
• pp.1-7
• /
• 2002

This paper studies on the human cognition of object's weight in virtual environment. We design the force input device which consists of a 3D mouse and a simple spring. It provides users with force feedback. The user can measure the weight of an object by the grasping force to move or lift it up in the virtual environment. Three kinds of experiments are performed. The first one is performed to analyze the relationships between the object's weight and its volume. The second one is to find the relationships between the object's weight and the its texture and finally the third one is to find the relationships between the object's weight and the force used to move an object. We conclude from the analysis of the experiment that object's volume or texture are not the critical factor for user to realize its weight. But the grasping force is critical and meaningful in realizing its weight so that the virtual environment with force cue provides users with more immersive environments. And, also the force input device is effective enough for user to feel the weight of the object.

• Journal of Drive and Control
• /
• v.18 no.4
• /
• pp.77-83
• /
• 2021

With the progress in virtual reality technology, various virtual objects can be displayed using head-mounted displays (HMD). However, force feedback sensations such as pushing against a virtual object are not possible with an HMD only. Focusing on force feedback, desktop-type devices are generally used, but the user cannot move in a virtual space because such devices are fixed on a desk. With a wearable force feedback device, users can move around while experiencing force feedback. Therefore, the authors have developed a wearable force feedback device using a magnetorheological fluid clutch and pneumatic rubber artificial muscle, aiming at presenting the elasticity, friction, and viscosity of an object. To date, we have developed a wearable four-degree-of-freedom (4-DOF) force feedback device and have quantitatively evaluated that it can present commanded elastic, frictional, and viscous forces to the end effector. However, sensory evaluation with a human has not been performed. In this paper, therefore, we conduct a sensory evaluation of the proposed method. In the experiment, frictional and viscous forces are rendered in a virtual space using a 4-DOF force feedback device. Subjects are asked to answer questions on a 1- to 7-point scale, from 1 (not at all) to 4 (neither) to 7 (strongly). The Wilcoxon signed rank test was used for all data, and answer 4 (neither) was used as compared standard data. The experimental results confirmed that the user could feel the presence or absence of viscous and frictional forces. However, the magnitude of those forces was not sensed correctly.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 1999.11a
• /
• pp.97-100
• /
• 1999

Human feels kinesthetic sense in response to the force acted on him. In order to represent kinesthetic sense, a force is analyzed as mechanical impedance (i.e., stiffness or damping) and implemented by active impedance control. In this research, a 3-dimensional arm motion generator is developed to present various mechanical impedance characteristics to an operator. An introduction of virtual reality provides not only a visual effect in virtual environment but also the change in force synchronized with the visual effect in real time.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.12
• /
• pp.180-187
• /
• 1998

The stability and theoretical performance limits of the feedback controlled force reflecting haptic manipulator have been discussed. All the virtual environment which interact physically with the haptic system have its own stable performance limit. Three different realization of the interfaces have been compared using the driving point admittance. The haptic system which is separated from the human hand or finger is superior to its stable interaction provided that there is a means to apply a direct damping between the haptic manipulator and the human finger Electro-magnetic force is used for its digital implementation of the simple separated type haptic device. The stable limits of a virtual wall is calculated and experimental results show that there is performance limits in this implementation.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.10
• /
• pp.1738-1745
• /
• 2016

In this paper, we present localization and autonomous navigation method using GPU(Graphics Processing Unit)-based SIFT(Scale-Invariant Feature Transform) algorithm and virtual force method for mobile robots. To do this, at first, we propose the localization method to recognize the landmark using the GPU-based SIFT algorithm and to update the position using extended Kalman filter. And then, we propose the A-star algorithm for path planning and the virtual force method for autonomous navigation of the mobile robot. Finally, we demonstrate the effectiveness and applicability of the proposed method through some experiments using the mobile robot with OPRoS(Open Platform for Robotic Services).

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.116.3-116
• /
• 2002

Introduction $\textbullet$Teleoperation System for Wiping Operation $\textbullet$Virtual Force Generation Algorithm $\textbullet$Virtual Velocity Generation Algorithm $\textbullet$Force-Force Control Technique $\textbullet$Experimental Results and Discussion $\textbullet$Conclusions

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.39 no.1
• /
• pp.31-36
• /
• 2016

Recently, Live-Virtual-Constructive (L-V-C) integrate training system has proposed as a solution for the problems such as limitation of training areas, increase of mission complexity, rise in oil prices. In order to integrate each training system into the one effectively, we should solve the issue about stress of pilots by the environmental differences between Live and Virtual simulation which could be occurred when each system is connected together. Although it was already examined in previous study that the psychological effects on pilots was occurred by the environmental differences between actual and simulated flights, the study did not include what the causal factors affecting psychological effects are. The aim of this study is to examine which environmental factors that cause pilots' psychological effects. This study analyzed the biochemical stress hormone, cortisol to measure the pilots' psychological effects and cortisol was measured using Enzyme-linked immunoassay (EIA). A total of 40 pilots participated in the experiment to compare the differences in pilots' cortisol response among live simulation, virtual simulation, and the virtual simulation applying three environmental factors (gravity force, noise, and equipment) respectively. As a result, there were significant differences in cortisol level when applied the gravity force and equipment factors to the virtual simulation, while there was no significant difference in the case of the noise factor. The results from this study can be used as a basis for the future research on how to make L-V system by providing minimum linkage errors and design the virtual simulator that can reduce the differences in the pilots' psychological effects.

• Journal of Industrial Technology
• /
• v.19
• /
• pp.415-421
• /
• 1999

In this paper, a 2D X-Y table, two axes of which are symmetrical, and a force sensing device are constructed, which comprise a 2D haptic interfacing apparatus. Two DC motors are used for actuating the two axes of the table and two precision encoders for sensing the position of each axis. Four PZTs are used for sensing the direction and the magnitude of the 2D force applied to the force sensing device by the user. The performance of the 2D haptic interface device is tested by 2D virtual object recognition experiments.

• Structural Engineering and Mechanics
• /
• v.42 no.1
• /
• pp.39-53
• /
• 2012

This paper presents an alternative way to derive the exact element stiffness matrix for a beam on Winkler foundation and the fixed-end force vector due to a linearly distributed load. The element flexibility matrix is derived first and forms the core of the exact element stiffness matrix. The governing differential compatibility of the problem is derived using the virtual force principle and solved to obtain the exact moment interpolation functions. The matrix virtual force equation is employed to obtain the exact element flexibility matrix using the exact moment interpolation functions. The so-called "natural" element stiffness matrix is obtained by inverting the exact element flexibility matrix. Two numerical examples are used to verify the accuracy and the efficiency of the natural beam element on Winkler foundation.