• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.463-467
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• 2005

In this paper, the guidance law applicable to formation flight of UAV in three-dimensional space is proposed. The concept of miss distance, which is commonly used in the missile guidance laws, and Lyapunov stability theorem are effectively combined to obtain the guidance commands of the wingmen. The propose guidance law is easily integrated into the existing flight control system because the guidance commands are given in terms of velocity, flight path angle and heading angle to form the prescribed formation. In this guidance law, communication is required between the leader and the wingmen to achieve autonomous formation. The wingmen are only required the current position and velocity information of the leader vehicle. The performance of the proposed guidance law is evaluated using the complete nonlinear 6-DOF aircraft system. This system is integrated with nonlinear aerodynamic and engine characteristics, actuator servo limitations for control surfaces, various stability and control augmentation system, and autopilots. From the nonlinear simulation results, the new guidance law for formation flight shows that the vehicles involved in formation flight are perfectly formed the prescribed formation satisfying the several constraints such as final velocity, flight path angle, and heading angle.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.196-196
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• 2000

This paper describes a lateral guidance system of an autonomous vehicle, using a neural network model of magneto-resistive sensor and magnetic fields. The model equation was compared with experimental sensing data. We found that the experimental result has a negligible difference from the modeling equation result. We verified that the modeling equation can be used in simulations. As the neural network controller acquires magnetic field values(B$\_$x/, B$\_$y/, B$\_$z/) from the three-axis, the controller outputs a steering angle. The controller uses the back-propagation algorithms of neural network. The learning pattern acquisition was obtained using computer simulation, which is more exact than human driving. The simulation program was developed in order to verify the acquisition of the teaming pattern, teaming itself, and the adequacy of the design controller. The performance of the controller can be verified through simulation. The real autonomous electric vehicle using neural network controller verified good results.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.11a
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• pp.123-126
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• 2006

본 논문은 자율주행차량과 로봇의 안내를 위한 자계위치인식시스템을 제안한다. 자계위치인식시스템은 자성체로부터 발생되는 자계를 측정하여 위치를 인식한다. 이러한 자계위치인식시스템에서 지구자계는 기본적인 왜란으로 작용한다. 본 논문에서는 지구자계의 영향을 제거하기 위해서 다수의 1축 자계센서 열을 구성하였으며, 자계센서 출력의 선형구간을 이용하여 정밀한 위치인식시스템을 개발하였다. 본 논문에서 제안하는 자계위치인식시스템은 실험을 통하여 그 실용성을 검증하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.12
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• pp.1217-1224
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• 2009

A simple and effective guidance and control scheme that enables autonomous three-dimensional path-following for a fixed wing aircraft is presented. The method utilizes the nonlinear path-following guidance law for the outer loop that creates steering acceleration command based on the desired flight path and the current position and velocity of the vehicle. The scheme considers the gravity in the guidance level, where it is subtracted from the acceleration command to form the specific force acceleration command which the aircraft is better suited to follow than the total acceleration command in the inner-loop. A roll attitude control scheme is also presented that enables inverted flight or sideslip maneuvers such as slow roll and knife-edge. A series of aerobatic maneuvers are demonstrated through simulations to show the potential of the proposed scheme.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.1
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• pp.43-56
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• 2011

An integrated system composed of guidance, navigation and control (GNC) system for autonomous proximity operations and the docking of two spacecraft was developed. The position maneuvers were determined through the integration of the state-dependent Riccati equation formulated from nonlinear relative motion dynamics and relative navigation using rendezvous laser vision (Lidar) and a vision sensor system. In the vision sensor system, a switch between sensors was made along the approach phase in order to provide continuously effective navigation. As an extension of the rendezvous laser vision system, an automated terminal guidance scheme based on the Clohessy-Wiltshire state transition matrix was used to formulate a "V-bar hopping approach" reference trajectory. A proximity operations strategy was then adapted from the approach strategy used with the automated transfer vehicle. The attitude maneuvers, determined from a linear quadratic Gaussian-type control including quaternion based attitude estimation using star trackers or a vision sensor system, provided precise attitude control and robustness under uncertainties in the moments of inertia and external disturbances. These functions were then integrated into an autonomous GNC system that can perform proximity operations and meet all conditions for successful docking. A six-degree of freedom simulation was used to demonstrate the effectiveness of the integrated system.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• v.10 no.2
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• pp.396-399
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• 2005

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.760-767
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• 2011

To strategically select the technology priority based on the understanding of technology development trends and prospects is very important. To provide such guidance for autonomous driving technology in unmanned ground combat vehicles, this report deals with followings; 1) The core technologies for autonomous driving are reviewed. 2) And domestic and foreign policies for relevant technology development are investigated. 3) Then, to estimate the technology development trend, the published patents and research papers are analyzed. 4) Based on those analyses, domestic technology level and development prospects are expected.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.335-335
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• 2000

Applications such as unmanned aerial vehicles (UAVs), autonomous underwater vehicles (AUVs) and the time varying nature of their navigation, guidance and control systems motivate an integrated approach to trajectory general ion and trajectory tracking for autonomous vehicles. In this paper, an experimental testbed was designed for studying this integrated trajectory control approach. In this paper we apply the separating approach to an autonomous nonlinear vehicle system. A new linear matrix inequality based H$_{\infty}$ control technique for periodic time-varying systems is applied to the role of trajectory tracking. Trajectory general ion is accomplished by exploit ing the differential flatness property of the vehicle system; this at lows product ion of desired feasible nominal or reference trajectories from certain ″flat'system outputs. Simulation and experimental results are presented showing stable tracking of a periodic circular trajectory.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.9 no.4
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• pp.315-320
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• 2009

The popularity of autonomous mobile robots have been rapidly increasing due to their new emerging application areas, from room cleaning, tourist guidance to space explorations. However, the development of a satisfactory control algorithm that will enable the autonomous mobile robots to navigate safely especially in dynamic environments is still an open research problem. In this paper, a newly proposed potential field based control method is implemented, analyzed, and improvements are suggested based on experimental results obtained from simulations. The experimental results are presented to show the effectiveness of the behavior-based control using the proposed potential field generation technique.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.1
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• pp.54-59
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• 2010

This paper present to study the guidance system as localization technique using sensor fusion and line tracking technique using virtual line for AGV(autonomous guided vehicle). An existing AGV could drive on decided line only. And representative guidance systems of such guidance system are magnet-gyro guidance and wired guidance. However, those have had the high cost of installation and maintenance, and the difficulty of system change according to variation of working environment. To solve such problems, we make the localization system which is fused with a laser navigation and gyro, encoder. The system is robust against noise, and flexible according to working environment through sensor fusion. For line tracking of laser navigation without wire guidance, we set the virtual line in program, and design the driving controller based on difference of angle and distance between AGV's position and decided virtual line. To experiment, we use the AGV which is made by ourselves, and experiment the line tracking repeatedly on same experimental environment. In result, maximum distance error between decided virtual line and AGV's position was less than 49.93mm, and we verified that the proposed system is efficient for line tracking of actual AGV.