• Journal of Institute of Control, Robotics and Systems
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• v.18 no.12
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• pp.1079-1085
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• 2012

For precise motion control, S-curve velocity profile is generally used but it has disadvantage of relatively long calculation time for floating-point arithmetics. In this paper, we present a new generating method for velocity profile to reduce delay time of profile generation so that it overcomes such disadvantage and enhances the efficiency of precise motion control. In this approach, the velocity profile is designed based on the gamma correction expression that is generally used in image processing to obtain a smoother movement without any critical jerk. The proposed velocity profile is designed to support both T-curve and S-curve velocity profile. It can generate precise profile by adding an offset to the velocity profile with decimals under floating point that are not counted during gamma correction arithmetic operation. As a result, the operation time is saved and the efficiency is improved. The proposed method is compared with the existing method that generates velocity profile using ring buffer on a 8-bit low-cost MCU. The result shows that the proposed method has no delay in generating driving profile with good accuracy of each cycle velocity. The significance of the proposed method lies in reduction of the operation time without degrading the motion accuracy. Generated driving signal also shows to verify effectiveness of the proposed method.

• Journal of Broadcast Engineering
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• v.17 no.1
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• pp.165-178
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• 2012

In most conventional video codecs, such as MPEG-2 and MPEG-4, inter coding is performed with the fixed motion vector resolution. When KTA software was developed, resolution for MVs can be selected in each slice. Although KTA codec uses a variety of resolutions for ME, the selected resolution is applied over the entire pixels in the slice and the statistical property of the local area is not considered. In this paper, we propose an adaptive decision scheme for motion vector resolution which depends on region, where MV search area is divided to multiple regions according to the distance from PMV. In each region, the assigned resolution is used to estimate MV. Each region supports different resolution for ME from other regions. The efficiency of the proposed scheme is affected from threshold values to divide the search area and the entropy coding method to encode the estimated MV. Simulation results with HM3.0 which is the reference software of HEVC show that the proposed scheme provides bit rate gains of 0.9%, 0.6%, and 2.9% in Random Access, Low Delay with B picture, and Low Delay with P picture structures, respectively.

• Structural Engineering and Mechanics
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• v.40 no.3
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• pp.431-451
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• 2011

Time delay inevitably exists in active control systems, and it may cause the degradation of control efficiency or instability of the systems. So time delay needs to be compensated in control design in order to eliminate its negative effect on control efficiency. Today time delay in linear systems has been more studied and some treating methods had been worked out. However, there are few treating methods for time delay in nonlinear systems. In this paper, an active controller for a nonlinear and hysteretic building structure with time delay is studied. The nonlinear and hysteretic behavior of the system is illustrated by the Bouc-Wen model. By specific transformation and augmentation of state parameters, the motion equation of the system with explicit time delay is transformed into the standard state space representation without any explicit time delay. Then the fourth-order Runge-Kutta method and instantaneous optimal control method are applied to the controller design with time delay. Finally, numerical simulations and comparisons of an eight-story building using the proposed time-delay controller are carried out. Simulation results indicate that the control performance will deteriorate if time delay is not taken into account in the control design. The simulations also prove the proposed time delay controller in this paper can not only effectively compensate time delay to get better control effectiveness, but also work well with both small and large time delay problems.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.3
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• pp.210-216
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• 2015

It is well known that the structure of brain and consciousness of human have a phenomena of complex system. The human emotion have a many kind. The love is one of human emotion, which have been studied in sociology and psychology as a matter of great interested thing. In this paper, we consider a same and different time delay in love equation of Romeo and Juliet. We represent a behavior of love as a time series and phase portrait, and analyze the difference of behaviors between a same and different time delay.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.63.5-63
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• 2001

In this paper, moving objects tracking and dynamic characteristic analysis are studied. Kohonen´s self-organizing neural network models are used for moving objects tracking and time delay neural networks are used for dynamic characteristic analysis. Instead of objects brightness, neuron projections by Kohonen Networks are used. The motion of target objects can be analyzed by using the differential neuron image between the two projections. The differential neuron image which is made by two consecutive neuron projections is used for center detection and moving objects tracking. The two differential neuron images which are made by three consecutive neuron projections are used for the moving trajectory estimation.

• Journal of Applied and Pure Mathematics
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• v.5 no.1_2
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• pp.23-40
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• 2023

This paper is concerned by the controllability results of impulsive neutral stochastic functional integrodifferential equations (INSFIDEs) driven by fractional Brownian motion with infinite delay in a real separable Hilbert space. The controllability results are obtained using stochastic analysis, Krasnoselkii fixed point method and the theory of resolvent operator in the sense of Grimmer. A practical example is provided to illustrate the viability of the abstract result of this work.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.463-474
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• 2015

Future Ground Control Stations (GCSs) for Unmanned Aerial Vehicles (UAVs) teleoperation targets better situational awareness by providing extra motion cues to stimulate the vestibular system. This paper proposes a new virtual environment for long range Unmanned Aerial Vehicle (UAV) control via Non-Line-of-Sight (NLoS) communications, which is based on motion platforms. It generates motion cues for the teleoperator for extra sensory stimulation to enhance the guidance performance. The proposed environment employs the distributed component simulation over GSM network as a simulation platform. GSM communications are utilized as a multi-hop communication network, which is similar to global satellite communications. It considers a UAV mathematical model and wind turbulence effects to simulate a realistic UAV dynamics. Moreover, the proposed virtual environment simulates a Multiple Axis Rotating Device (MARD) as Human Machine Interface (HMI) device to provide a complete delay analysis. The demonstrated measurements cover Graphical User Interface (GUI) capabilities, NLoS GSM communications delay, MARD performance, and different software workload. The proposed virtual environment succeeded to provide visual and vestibular feedbacks for teleoperators via GSM networks. The overall system performance is acceptable relative to other Line-of-Sight (LoS) systems, which promises a good potential for future long range, medium altitude UAV teleoperation researches.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.708-715
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• 2010

In Strapdown Inertial Navigation System, alignment accuracy is the most important factor to determine the performance of navigation. However by an existing self-alignment method, it takes a long time to acquire the alignment accuracy that we want. So, to attain the desired alignment accuracy in as little as $\bigcirc$ minutes, we have developed the precise multi-position alignment method. In this paper, it is proposed a inertial measurement matching transfer alignment method among alignment methods to minimize the alignment error in a short time. It is based on a mixed velocity-DCM matching method be suitable to the operating environment of vertical launching system. The compensation methods to reduce misalign error, especially azimuth angle error incurred by measurement time-delay error and body flexure error are analyzed and evaluated with simulation. This simulation results are finally confirmed by experimentations using FMS(Flight Motion Simulator) in Lab and the integration test to follow the fire control mission.

• Journal of Broadcast Engineering
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• v.16 no.6
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• pp.1069-1072
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• 2011

This paper proposes the method which reduces complexity and improves coding efficiency by solving a problem of HEVC bi-prediction. In current HM 3.0, it is frequently occurred that L0 motion information and L1 motion information are identical in blocks which are bi-predicted. In this case, L1 motion vector is replaced by non-zero motion vector which belongs to first available neighbor block of current block. If they are still identical, prediction mode is replaced by uni-prediction. As an experimental result, in LD(Low-Delay) case, decoding time is reduced roughly 2%~5% and coding gain is roughly 0.3%~0.5% compared with the HM 3.0 anchor.

• Structural Engineering and Mechanics
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• v.58 no.6
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• pp.1127-1143
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• 2016

The pounding phenomenon in adjacent structures happens in severing earthquakes that can cause great damages. Connecting neighboring structures with active and semi-active control devices is an effective method to avoid mutual colliding between neighboring buildings. One of the most important issues in control systems is applying online control force. There will be a time delay if the prose of producing control force does not perform on time. This paper proposed a time-delay compensation method in coupled structures control, with semi-active Magnetorheological (MR) damper. This method based on Newmark's integration is adopted to mitigate the time-delay effect. In this study, Lyapunov's direct approach is employed to compute demanded voltage for MR dampers. Using Lyapunov's direct algorithm guarantees the system stability to design a controller based on feedback. Because of the strong nonlinearity of MR dampers, the equation of motion of coupled structures becomes an involved equation, and it is impossible to solve it with the common time step methods. In present paper modified Newmark-Beta integration based on the instantaneous optimal control algorithm, used to solve the involved equation. In this method, the response of a coupled system estimated base on optimal control force. Two MDOF structures with different degrees of freedom are finally considered as a numeric example. The numerical results show, the Newmark compensation is an efficient method to decrease the negative effect of time delay in coupled systems; furthermore, instantaneous optimal control algorithm can estimate the response of structures suitable.