• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1332-1335
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• 1996

It is very important to predict the future position for the heavy vehicle with evasive maneuvering. In this paper, we considered for the manual image tracking system. The vehicle images are received from gyro stabilized mirror system, pass through the optical lens, processed, and displayed on the TV monitor. The operator try to lay the reticle to the center of vehicle image. When the vehicle is moving, the mirror platform (actually the line of sight) should follow the vehicle and the angular rate information is picked up from the mirror stabilized system. This rate signal should be used to predict the future vehicle position. The problem is that the visual system of the human operator is in the closed loop system. The rate signals are disturbed by the operator. In addition, there are some non linearities concerned with the control handle bar and the servo control system. The proposed Kalman filter, combined with some modifications for operator disturbance rejection, improved the predication of the future vehicle position when compared with the conventional passive filter used.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.115.5-115
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• 2002

In this paper, we introduce a system that detects all kinds of violations at a street intersection such as red light running, speed violation, stop line violation and lane violation by tracking individual vehicles. Two cameras are used for defecting violations. One is an analog camera for real-time tracking and the other is a digital camera for license plate reading. This system is connected to the traffic signal system controller and monitors the red, arrow, yellow and green phases of an approach. Two loops in the road are used to detect vehicle approach and speed. The system takes pictures of all vehicles passing a second loop and tracks the vehicles until they go out a street intersection...

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.495-501
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• 2011

The characteristics of a discriminator estimating a tracking error in a signal tracking loop of a GPS receiver can be affected by the noise power, and the slope of the discriminator function is actually lowered as the noise power increases. In this paper, an algorithm to compensate the lowered slope of the function using the estimated C/N0 is studied, and a new design method of a code tracking which provides more accurate tracking error than a conventional one by adopting the compensation algorithm is proposed. Through the experimental results, finally, it has been check that the accuracy of the proposed DLL is enhanced about 50% when the dynamics of the vehicle is 20g/s.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2641-2647
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• 2003

Conventional DLLs estimate the delay times of satellite signals individually and feed back these measurements to the VCO independently. But VDLL estimates delay times and user position directly and then estimate the feedback term for VCO using the estimated position changes. In this process, input measurements are treated as vectors and these vectors are used for navigation. First advantage of VDLL is that noise is reduced in all of the tracking channels making them less likely to enter the nonlinear region and fall below threshold. Second is that VDLL can operate successfully when the conventional independent parallel DLL approach fails completely. It means that VDLL receiver can get enough total signal power to track successfully to obtain accurate position estimates under the same conditions where the signal strength from each individual satellite is so low or week that none of the individual scalar DLL can remain in lock when operating independently. To operate VDLL successfully, it needs to know the initial user dynamics and position and prevents total system from the divergence. The suggested integration method is to use the inertial navigation system to provide initial dynamics for VDLL and to maintain total system stable. We designed the GPS/INS integrated navigation system. This new type of integrated system contained the vector pseudorange format generation block, VDLL signal processing block, position estimation block and the conversion block from position change to delay time feedback term aided by INS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9C
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• pp.905-913
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• 2006

In the impulse radio ultra-wideband communication systems, the residual timing offset exists when the acquisition and tracking of the timing synchronization is well done. And the offset affects the performance of the system dramatically. In order to compensate the offset, we present the digital phase-locked loop that uses the reference signal in the correlation detection receiver. First, we show the degradation of BER performance that is caused by the offset, and then compensation process of the timing tracker and performance improvement. In this paper, the timing detector in the tracker operates at the sampling period of frame level uses the correlation between received and reference signal. Also, we present the performance comparison by using the computer simulation results for different Gaussian monocycle pulses.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.11
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• pp.1069-1076
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• 2007

This paper presents the road simulator control technology for reproducing the road input signal to implement the real road data. The simulator consists of the hydraulic pump, servo valve, hydraulic actuator and its control equipment. The QFT(Quantitative Feedback Theory) is utilized to control the simulator effectively. The control system illustrates a tracking performance of the closed-loop controller with low order transfer function G(s) and pre-filter F(s) for a parametric uncertain model. A force controller is designed to communicate the control signal between simulator and digital controller. Tracking specification is satisfied with upper and lower bound tolerances on the steep response of the system to the reference signal. The efficacy of the QFT force controller is verified through the numerical simulation, in which combined dynamics and actuation of the hydraulic servo system are tested. The simulation results show that the proposed control technique works well under uncertain hydraulic plant system. The conventional software (Labview) is used to make up for the real controller in the real-time basis, and the experimental works show that the proposed algorithm works well for a single road simulator.

• Journal of Advanced Navigation Technology
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• v.15 no.1
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• pp.32-38
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• 2011

In this paper, code and carrier tracking error which resulted from spoofing signal was analyzed by simulation. For a start, the types of spoofing signals and methods were classified. For the simulation, search spoofing method is assumed because a perfect position and velocity are not generally informed to spoofing device. In most cases, the tracking error is increased but a complete deception does not happen because of the inherent anti-spoofing characteristics of the GPS signal.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.289-292
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• 1997

In this paper, a continuous sliding mode controller for robot manipualator is proposed. The proposed scheme guarantees that the tracking error converges to zero maintaining the smoothness of the actual control signal. In order to estimate the acceleration data, a sliding mode observer is used, and the stability of the closed-loop system is shown.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.6
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• pp.606-614
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• 1991

A robust direct adaptive controller with respect to additive and multiplicative unmodeled dynamics is designed. A new term, proportional to the product of the bounded tracking error and normalizing signal, is added to the conventional control input for improvement of robustness and performances of an adaptive system. It is shown by the mathematical analysis and simulation results that the stability of the closed loop system is guaranteed and the performance of the system is improved.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.332-337
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• 1988

A digital series-feedback compensator algorithm for tracking time-varying signal is presented. The series-feedback compensator is composed of one closed loop pole / zero cancellation compensator and one desired-input generator. This algorithm is applied to nonlinear hydraulic position control system. The hydraulic servo system is modelled as a second order linear model and cancellation compensator is modelled from it. The desired input generator is inserted to reduce modelling error. Digital computer simulation output using this control method is present and the usefulness of this control algorithm for nonlinear hydraulic system is verified.