• International Journal of Fuzzy Logic and Intelligent Systems
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• 제13권4호
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• pp.307-314
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• 2013

We designed and implemented a fork-type automatic guided vehicle (AGV) with a laser guidance system. Most previous AGVs have used two types of guidance systems: magnetgyro and wire guidance. However, these guidance systems have high costs, are difficult to maintain with changes in the operating environment, and can drive only a pre-determined path with installed sensors. A laser guidance system was developed for addressing these issues, but limitations including slow response time and low accuracy remain. We present a laser guidance system and control system for AGVs with laser navigation. For analyzing the performance of the proposed system, we designed and built a fork-type AGV, and performed repetitions of our experiments under the same working conditions. The results show an average positioning error of 51.76 mm between the simulated driving path and the driving path of the actual fork-type AGV. Consequently, we verified that the proposed method is effective and suitable for use in actual AGVs.

• 제어로봇시스템학회논문지
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• 제11권8호
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• pp.726-732
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• 2005

This paper proposes an autolanding guidance and control algorithm with the lateral guidance law. This algorithm is basically formulated and designed in feedback linearization based on singular perturbation. Main features of this algorithm are two facts. One of those is that when a certain situation happens that airplane must realign to the runway suddenly assigned due to unexpected environment change around the landing site, the heading guidance in this algorithm is very valuable, and the other is the fact that the inner loop control of this algorithm is able to be designed directly based on the Handling Quality Requirements that most flight control systems must be satisfied with. To illustrate the potential of this algorithm, 6-DOF nonlinear simulation based on the nonlinear airplane model shown in Ref.[11] is carried out. The simulation results showed that the altitude response to the given landing trajectory is accurate, and the airplane heading alignment to the assigned runway from the lateral deviation is successful. It is noted that this algorithm is also applicable to unmanned aerial vehicle, which can be retrieved in autolanding technique, where the runway far retrieving the vehicle is in any direction for example at war field.

• 한국항공우주학회지
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• 제30권7호
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• pp.81-89
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• 2002

현재까지 개발된 다양한 형태의 유도법칙은, 유도개념에 따라 추적방식, 미사일과 표적에 의해 정의되는 방위각을 일정하게 유지시키는 유도법칙, 그리고 표적의 기동 예측에 기반한 유도법칙 등으로 분류할 수 있다. 본 논문에서는 이러한 개념적인 유도목적을 일반화한 유도법칙을 제안하였다. 제안한 유도법칙은 충돌삼각형 상에서 정의된 목표각을 사용하는데, 목표각은 매개변수의 설정에 따라 다양한 형태가 될 수 있다. 르야프노프 이론을 사용하여, 제안한 유도법칙은 목표각 오차의 반응이 1차 시스템과 동일함을 증명하였다. 그리고 자동조종장치의 동역학이 느릴 경우는, 목표각 오차 반응을 2차 시스템으로 모사할 수 있는 유도법칙도 제안하였다. 제안한 유도법칙의 유용성을 보이기 위하여 측정잡음을 포함한 시뮬레이션을 수행하고 결과를 제시하였다.

• 산업공학
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• 제15권4호
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• pp.374-381
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• 2002

In this paper, we design and implement a real-time route guidance system(RGS) in large-scale networks. Coupled with the well-known mathematical routing algorithms, we devise an RGS for knowledge aquisition and self-learning ability within the framework of the expert system. Through off-line construction of database, on-line treatment of unexpected traffic accidents, etc., the developed RGS can provide drivers with good quality real-time routing information. The practical effectiveness of the proposed system is demonstrated in terms of response time and route appropriateness.

• 대한임베디드공학회논문지
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• 제11권3호
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• pp.153-162
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• 2016

This paper proposes an optimal dynamic resource allocation method in IoT (Internet of Things) parking guidance system using Q-learning resource allocation model. In the proposed method, a resource allocation using a forecasting model based on Q-learning is employed for optimal utilization of parking guidance system. To demonstrate efficiency and availability of the proposed method, it is verified by computer simulation and practical testbed. Through simulation results, this paper proves that the proposed method can enhance total throughput, decrease penalty fee issued by SLA (Service Level Agreement) and reduce response time with the dynamic number of users.

• 제어로봇시스템학회논문지
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• 제18권2호
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• pp.87-93
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• 2012

In this paper, a formation guidance method for UAVs (Unmanned Aerial Vehicles) to simulate the formation flight of birds proposed. The proposed method solves all issues of approaching for formation, formation keeping, and scarce chance to be collided with each UAV during formation process. Also, we design the feedforward controller to compensate the change of speed and heading for maneuvering of the leader UAV and the feedback controller to consider the response lag of the system. The stability and performance of the proposed controller is verified via numerical simulations of the full 6-Dof model of UAV.

• Nuclear Engineering and Technology
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• 제48권3호
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• pp.831-839
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• 2016

Seismic qualification by test is widely used as a way to show the integrity and functionality of equipment that is related to the overall safety of nuclear power plants. Another means of seismic qualification is by direct integration analysis. Both approaches require a series of time histories as an input. However, in most cases, the possibility of using real earthquake data is limited. Thus, artificial time histories are widely used instead. In many cases, however, response spectra are given. Thus, most of the artificial time histories are generated from the given response spectra. Obtaining the response spectrum from a given time history is straightforward. However, the procedure for generating artificial time histories from a given response spectrum is difficult and complex to understand. Thus, this paper presents a simple time-domain method for generating a time history from a given response spectrum; the method was shown to satisfy conditions derived from nuclear regulatory guidance.

• 한국항공우주학회지
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• 제40권6호
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• pp.506-514
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• 2012

본 논문에서는 비행체의 운동 역학을 고려한 경로 추종을 위한 시선각 유도 법칙의 유도 게인 설계 기법에 대해 기술하였다. 비례-미분 게인과 접근 거리의 설계 변수로 구성된 시선각 기반 유도 법칙은 유도 게인 결정시 대부분 경험적 또는 실험적인 방법으로 설계하는 것이 일반적인데 이러한 경우 정밀하고 일관적인 경로 추종 성능 보장이 어렵고 비행체 기동 한계 및 운용 속도 등에 따라 설계 변수를 재설계해야하는 단점이 있다. 이러한 단점을 보완하기 위해 본 연구에서는 비행체의 속도에 따른 운동 역학을 고려하여 설계 변수의 개수를 최소화하고 비행 속도에 따라 유도 법칙 게인이 변화되어 정밀한 경로 추종이 가능할 뿐만 아니라 안정적이고 일관된 성능을 갖는 유도 법칙의 게인 설정 기법을 제안하였다. 제안된 기법은 비행체의 자세에 대한 1차 응답 속도를 고려한 비선형 시뮬레이션을 수행하여 추종 성능을 평가하였으며 선형 경로와 원형 경로에 대한 비행 시험 을 통해 추종 성능 및 알고리듬의 타당성을 실험적으로 확인하였다.

• Transactions on Control, Automation and Systems Engineering
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• 제4권4호
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• pp.283-288
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• 2002

This paper has shown that the impulse and the unit step responses of 2nd-order systems can be computed by an analytic method. Three different 2nd-order systems are investigated: the prototype system, the system with one LHP(left half plane) real zero and the system with one RHP(right half plane) real zero. It has also shown that the effects of the LHP or the RHP zero are very serious when the zero is getting closer to the origin on the complex plane. Based on these analytic results, this paper has presented two sufficient and necessary conditions for 2nd-order linear SISO(single-input/single-output) stable systems to have the nonovershooting and the monotone nondecreasing step response, respectively. The latter condition can be extended to the sufficient conditions for the monotone nondecreasing step response of high-order systems.

• 한국항해항만학회지
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• 제42권5호
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• pp.323-330
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• 2018

The Korean e-Navigation system is a Korean approach to correspond with implementation of IMO e-Navigation. It provides five services, among them SV20 service, a ship remote monitoring system that collects and processes sensor information related to fire, navigation, and seakeeping performance safety. The system also detects abnormal conditions such as fires, capsizing, sinking, navigation equipment failure during navigation, and calculates the safety index and determines the emergency level. According to emergency level, it provides appropriate emergency response guidance for the onboard operator. The fire safety module is composed of three sub-modules; each module is the safety index sub-module, the emergency level determination sub-module and emergency response guidance sub-module. In this study, operational concept of the fire safety module in SV20 service is explained, and fire safety assessment factors are estimated, to calculate the fire safety index. Fire assessment factors included 'Fire detector position factor,' 'Smoke diffusion rate factor,' and 'Fire-fighting facilities factor.'