• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.3
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• pp.68-75
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• 2004

Recently, need of the parallel manipulator requiring superior precision is increasing for medical application and precision manufacturing. In this study, we convert a given complex translation trajectory of the moving platform into a set of segments and hence a complex motion of the moving platform can be tractable and easily controled in a very limited workspace. In addition force exerted. to each link is minimized so that the minimized force can be transmitted to the end effector of the moving platform. An user friendly program is developed to design Gough-type 6DOF parallel manupulator based on the proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.213-216
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• 1996

This paper studies a class of in-parallel manipulators with special geometry where the forward displacement analysis problem can be solved easier than the fully parallel manipulators. Three horizontal links of this mechanism provide 3DOFs(Degrees of Freedom), which are one degree of orientational freedom and two degrees of translatory freedom. Three vertical links of this mechanism provide 3DOFs, which are two degrees of orientational freedom and one degree of translatory freedom. The main advantages of this manipulator, compared with the Stewart platform type, are the capability to produce pure rotation and to predict the motion of the moving platform easily. Since this manipulator has simple kinematic characteristics compared with the Stewart platform, controlling in real-time is possible due to less computational burden. The purpose of this investigation is to develope an analytical method and systematic method to analyze the basic kinematics of the manipulator. The basic kinematic equations of the manipulator are derived and simulation is carried out to show the performance of the mechanism.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.475-480
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• 2000

A new positioning mechanism with Parallel type actuator using piezoelectric material and with dual type actuators using voice coil motor (VCM) and piezoactuator is proposed for optical disk drive or near-field recording type drive, and high speed position and vibration control are investigated. Parallel type bimorph piezoactuator is used as a fine motion actuator with self-sensing technique, which allows a piezoelectric material to concurrently sense and actuate in a closed loop frame work, and positive position feedback control algorithm is adopted to further control residual vibration. For positioning control of VCM, PID control algorithm is adopted.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.162-169
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• 2000

In this paper, we develop a parallel inverted pendulum system that has the characteristics of the strongly coupled dynamics of motion by an elastic spring, the time-variant system parameters, and inherent instability, and so on. Hence, it is possible to approximate some kinds of a physical system into this representative system and to apply the various control theories to this system in order to verie their fidelity and efficiency. For this purpose, an experimental system of the parallel inverted pendulum has been implemented, and a control scheme using the eigenstructure assignment for decoupling control is presented in comparison with the conventional LQR optimal control method. Furthermore, this system can be utilized as a testbed to develop and evaluate new control algorithms through various setups. Finally, in this paper, the results of the experiment are compared with those of numerical simulations for validation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5497-5512
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• 2016

An improved optimal weights based on parallel interference cancellation algorithm has been proposed to cancel for interference induced by multi-user access satellite to ground uplink system. Due to differences in elevation relative motion between the user and the satellite, as well as access between users, resulting in multi-user access interference (Multi-user Access Interference, MUI), which significantly degrade system performance when multi-user access. By steepest gradient method, it obtained based on the MMSE criterion, parallel interference cancellation adjust optimal weights to obtain the maximum SINR. Compared to traditional parallel interference cancellation (Parallel Interference Cancellation, PIC) algorithm or serial interference cancellation ( Successive interference Cancellation, SIC), the accuracy of which is not high and too many complex iterations, we establish the multi-user access to the satellite to ground up link system to demonstrate that the improved WPIC algorithm could be provided with high accuracy and relatively low number of iterations.

• The Journal of Korea Robotics Society
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• v.6 no.1
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• pp.78-85
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• 2011

This article investigates kinematic characteristics of a Sch$\ddot{o}$nflies motion generator which represents a mechanism having translational three Degree-of-Freedom (DOF) and rotational one-DOF motion about a fixed axis. The mechanism consists of the base plate and the moving plate, and four identical limbs connecting them. Each limb employs two revolute joints (RR), one parallelogram (Pa), and two revolute joints (RR) from the base plate to the moving plate. The mechanism is driven by four actuators which are placed on the base plate to minimize dynamic loads. It is shown through simulations that the mechanism can be designed to secure large dexterous workspace and thus has very high potential for actual applications such as haptic devices and high-speed requiring tasks such as pick-and-place operations, riveting, screwing tasks, etc.

• Journal of Integrative Natural Science
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• v.12 no.4
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• pp.105-115
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• 2019

In this paper, a prediction system is proposed to control the brightness of smart street lamps by predicting the moving path through the reduction of consumption power and information of pedestrian's past moving direction while meeting the function of existing smart street lamps. The brightness of smart street lamps is adjusted by utilizing the walk tracking vector and soft hand-off characteristics obtained through the motion sensing sensor of smart street lamps. In addition, the motion vector is used to analyze and predict the pedestrian path, and the GPU is used for high-speed computation. Pedestrians were detected using adaptive Gaussian mixing, weighted difference imaging, and motion vectors, and motions of pedestrians were analyzed using the extracted motion vectors. The preprocessing process using linear interpolation is performed to improve the performance of the proposed prediction system. Fuzzy prediction system and neural network prediction system are designed in parallel to improve efficiency and rough set is used for error correction.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.38-40
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• 2007

In this paper, we propose a novel architecture, which is based on DCT (Discrete Cosine Transform), for ME (Motion Estimation) and MC (Motion Compensation). The traditional algorithms of ME and MC based on DCT did not suffer the advantage of the coarseness of the 2-dimensional DCT (2-D DCT) coefficients to reduce the operational time. Therefore, we derive a recursion equation for transform-domain ME and MC and design the structure by using highly regular, parallel, and pipeline processing elements. The main difference with others is removing the IDCT block by using to transform domain. Therefore, the performance of our algorithm is more efficient in practical image processing such as DVR (Digital Video Recorder) system. We present the simulation result which is compare with the spatial domain methods. it shows reducing the calculation cost. compression ratio. and peak signal to noise ratio (PSNR).

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.146-151
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• 2001

The Grand-Touring is a game motion simulator that simulates the race-car driving motion with three hydraulic cylinders which connect the platform and base in parallel. Its motion control system consists of the PC-based main controller and micro-controller based sub-controller. The former one process the dynamic image of race-car in response to the driver's action and computes the reference command for each cylinder and the latter one is designed for the tracking control of hydraulic cylinder and interfacing the auxiliary signals between various sensors/actuator and main controller. In this research, we developed the sub-controller that implements the required functions of Grand-Touring and prove the overall performance with experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.11a
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• pp.335-336
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• 2007