• International Journal of Automotive Technology
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• v.6 no.4
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• pp.351-357
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• 2005

Development of a real-time simulation model for high-speed and multibody tracked vehicles is difficult because they involve hundreds of highly nonlinear equations. In the development of a reliable tracked vehicle model for real-time simulation, it is helpful to use an off-line tracked vehicle model developed by considering all the degrees of freedom of each element. This paper presents a step-by-step procedure for the development of a real-time simulation model based on the off-line tracked vehicle model. The road input data, Profile IV, is used for the real time simulation and simulation results are compared with vehicle test results obtained in the military test field. It is noted that the simulation results are quite close to the test results.

• Journal of Industrial Technology
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• v.22 no.B
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• pp.251-260
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• 2002

In this thesis, a three degrees of freedom robot, which is able to provide sufficient precision for various robot researches, has been developed. The cable mechanism is used as a basic transmission of robot joints. Based on an optimal design strategy, link and joint parameters are determined and then overall geometry of the robot is designed. As an architecture of robot control, real time control system using real time linux and RtiC-Lab(Real Time Controls Laboratory) is developed. This system, written in C and based on Linux O/S, includes text editor, compiler, downloader, and real time plotter running in host computer for developing control purpose. Using these hardware and software, simple PD position control is implemented, the results shows the effectiveness of the system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.24 no.1
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• pp.1-9
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• 2016

In this paper, we integrate three degree of freedom(3DOF) point-mass model for aircraft and three-dimensional path generation algorithms using dubins curve and nonlinear path tracking law. Through this integration, we apply the path generation algorithm to the path planning, and verify tracking performance and feasibility of using the aircraft 3DOF point-mass model for air traffic management. The accuracy of modeling 6DOF aircraft is more accurate than that of 3DOF model, but the complexity of the calculation would be raised, in turn the rate of computation is more likely to be slow due to the increase of degree of freedom. These obstacles make the 6DOF model difficult to be applied to simulation requiring real-time path planning. Therefore, the 3DOF point-mass model is also sufficient for simulation, and real-time path planning is possible because complexity can be reduced, compared to those of the 6DOF. Dubins curve used for generating the optimal path has advantage of being directly available to apply path planning. However, we use the algorithm which extends 2D path to 3D path since dubins curve handles the two dimensional path problems. Control law for the path tracking uses the nonlinear path tracking laws. Then we present these concomitant simulation results.

• Structural Engineering and Mechanics
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• v.63 no.1
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• pp.115-124
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• 2017

In this paper, a different technique to predict the effects of soil-structure interaction (SSI) on seismic response of building systems is investigated. The technique use a machine learning algorithm called Support Vector Regression (SVR) with technical and analytical results as input features. Normally, the effects of SSI on seismic response of existing building systems can be identified by different types of large data sets. Therefore, predicting and estimating the seismic response of building is a difficult task. It is possible to approximate a real valued function of the seismic response and make accurate investing choices regarding the design of building system and reduce the risk involved, by giving the right experimental and/or numerical data to a machine learning regression, such as SVR. The seismic response of both single-degree-of-freedom system and six-storey RC frame which can be represent of a broad range of existing structures, is estimated using proposed SVR model, while allowing flexibility of the soil-foundation system and SSI effects. The seismic response of both single-degree-of-freedom system and six-storey RC frame which can be represent of a broad range of existing structures, is estimated using proposed SVR model, while allowing flexibility of the soil-foundation system and SSI effects. The results show that the performance of the technique can be predicted by reducing the number of real data input features. Further, performance enhancement was achieved by optimizing the RBF kernel and SVR parameters through grid search.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.8
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• pp.81-87
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• 2020

A stable rotational-to-linear motion transformation structure using a driving mechanism with 2 degrees of freedom was developed for an orthogonal mechanism to prevent the interference of each axis in 2D motion. In this mechanism, a step motor was used for precise position control. This structure was developed to maneuver workparts in micro particle blast machining experiments. To determine the real-time performance of micro particle blast machining, the control, input, and output were operated simultaneously and precise position control was implemented, using a timer interrupt with multiple execution codes. The two step motors obtained precise position control by removing backlash with a ball-screw mechanism. The device has menu-type control codes for user-friendliness, and real-time sequence control was simultaneously adopted for user control input.

• Journal of Mechanical Science and Technology
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• v.19 no.6
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• pp.1290-1303
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• 2005

In this research, a remote control system has been developed and implemented, which combines autonomous obstacle avoidance in real-time with force-reflective tele-operation. A tele-operated mobile robot is controlled by a local two-degrees-of-freedom force-reflective joystick that a human operator holds while he is monitoring the screen. In the system, the force-reflective joystick transforms the relation between a mobile robot and the environment to the operator as a virtual force which is generated in the form of a new collision vector and reflected to the operator. This reflected force makes the tele-operation of a mobile robot safe from collision in an uncertain and obstacle-cluttered remote environment. A mobile robot controlled by a local operator usually takes pictures of remote environments and sends the images back to the operator over the Internet. Because of limitations of communication bandwidth and the narrow view-angles of the camera, the operator cannot observe shadow regions and curved spaces frequently. To overcome this problem, a new form of virtual force is generated along the collision vector according to both distance and approaching velocity between an obstacle and the mobile robot, which is obtained from ultrasonic sensors. This virtual force is transferred back to the two-degrees-of-freedom master joystick over the Internet to enable a human operator to feel the geometrical relation between the mobile robot and the obstacle. It is demonstrated by experiments that this haptic reflection improves the performance of a tele-operated mobile robot significantly.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1275-1278
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• 1997

Cutting process has been automated by progress of CNC and CAD/CAM, but polishing process has been depended on only experiential knowledge of expert. To automate the polishing pricess polishing robot with 2 degrees of freedom which is attached to a machining center with 3 degrees of freedom has been developed. this automatic polishing robot is able to keep the polishing tool normal on the curved surface of die to improve a performance of polishing. Polishing task for a curved surface die demands repetitive operation and high precision, but conventional control algorithm can not cope with the problem of disturbance such as a change of load. In this research, we develop robust controller using real time sliding mode algorithm. To obtain gain parameters of sliding model control input, the signal compression method is used to identify polishing robot system. To obtain an effect of 5 degrees of freedom motion, 5 axes NC data for polishing are divided into data of two types for 3 axis machining center and 2 axis polishing are divided into data of two types for 3 axis machining center and 2 axis polishing robot. To find an efficient polishing condition to obtain high quality, various experiments are carried out.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2301-2309
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• 2018

In a field-oriented vector-controlled permanent magnet synchronous motor (PMSM) control system, the d-axis current control loop can offer a free degree of freedom which can be used to improve control performances. However, in the industry the desired d-axis current command is usually set as zero without using the free degree of freedom. This paper proposes a method to use the degree of freedom for control performance improvement. It is assumed that both the inner loop proportional-integral (PI) current controller and the q-axis outer loop PI speed controller are tuned by the well-known tuning rules. This paper gives an optimal d-axis reference current command generator such that some useful performance indexes are minimized and/or a tradeoff between conflicting performance criteria is made. This paper uses a differential evolution algorithm to autotune the parameter values of the optimal d-axis reference current command generator. This paper implements the proposed control system in real time on a Texas Instruments TMS320F28335 floating-point DSP. This paper also gives experimental results showing the practicality and feasibility of the proposed control system, along with simulation results.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.8
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• pp.929-937
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• 2005

A lattice BGK model based on a finite difference scheme with an internal degree of freedom is employed and it is shown that a diatomic 9as such as air is successfully simulated In a weak compressive wane problem and Coutte flow, the validity and characteristics of the applied model are examined. With the model. furthermore. we present a 2-dimensional edge tones to predict the frequency characteristics of discrete oscillations of a jet-edge feedback cycle by the FDLB model (I.D.F FDLBM) in which any specific heat ratio $\gamma$ can be chosen freely. The jet is chosen long enough in order to guaranteed the Parabolic velocity profile of a jet at the outlet. and the edges have of an angle of $\alpha$=$23^{0}$ and $20^{0}$. A sinuous instability wane with real frequency resulting from Periodic oscillation of the jet around the edge is propagated on the upper and lower of wedge.

• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.1-9
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• 2018

Present study investigated the crash phenomenon between freedom of press and pseudo press. For that researcher gathered online witch hunt cases from 2012 to 2017 and interpret with the logical basis of argument which needs to control pseudo press activity. On the other hand, present research arranged former studies about freedom of press and right of reputation and privacy as a counterpart that can be ethical debate. Futhermore, court case about right of small independent media where has less than 5 people also gathered. By Comparison of each ethical and legal basis, this study provide the insight which can inspire to think about real right of citizen and press.