Hong-Tae Jeon

On the linearization via a restricted class of dynamic feedback

We deal with the problem of linearization of nonlinear systems using a restricted class of dynamic compensator which is composed of chains of integrators, followed by static feedback in the vector field formulation. We present an upper bound on the number of integrators to linearize nonlinear systems, and show that the bound is sharp when n-2/spl ges/m/spl ges/2. This results in the checkable necessary and sufficient conditions.

Constant Altitude Flight Control for Quadrotor UAVs with Dynamic Feedforward Compensation

This study addresses the control problem of an unmanned aerial vehicle (UAV) during the transition period when the flying mode changes from hovering to translational motion in the horizontal plane. First, we introduce a compensation algorithm that improves height stabilization and reduces altitude drop. The main principle is to incorporate pitch and roll measurements into the feedforward term of the altitude controller to provide a larger thrust force. To further improve altitude control, we propose the fuzzy logic controller that improves system behavior. Simulation results presented in the paper highlight the effectiveness of the proposed controllers.

Collision-Avoidance and Optimal Path Planning of Autonomous Mobile Robot using Soft-Computing

Abstract Recently, the necessity of the autonomous mobile robot is empha sized in order to enlarge the scope of activity and actively cope with the change of work environment. This paper p roposes the algorithm which enables the mobile robot to avoid obstacles and lead it to the destination by the shortest path. And we verify the usability by a simulation. We made the algorithm with micro-GA and λ-geometry MRA. The area of simulation is limited to 320(width)X200(length) pixels and one pixel is one centimeter. When we planned the path with only λ-geometry MRA, we could find the direction for path planning but could not find the shortest path. But when we planned the path with λ-geometry MRA and micro-GA, we could find the shortest path. So the algorithm enables us to find the direction for path planning and the shortest path. Key Words : Micro-GA, λ-Geometry MRA, Optimal path planning, Collision avoidance 1. 서 론 과거 산업 현장에서 응용되고 있는 대부분의 로봇은 매니플레이터(manipulator)방식으로서 한정된 공간 안에서 제한된 작업을 수행하였지만, 최근 들어 로봇은 산업 현장뿐만 아니라 병원, 사무실, 가정, 전시장과 같은 여러 환경에서 각각의 목적에 맞는 기능을 수행하고 있다. 이에 따라 로봇은 넓은 활동 범위를 수용하고 작업 환경의 변화에 능동적으로 대처할 수 있어야 한다. 즉 작업 공간의 제한성을 해결하고 더 많은 작업 능력을 갖기 위하여 자율 이동 로봇(autonomous mobile robot)에 대한 필요성이 높아지고 있고 이와 관련된 여러 가지 연구가 진행되고 있다.자율 이동 로봇의 지능화란 어떤 임무가 주어졌을 때 자기 스스로 감지기(sensor)로 주변의 환경과 자신의 위치나 상태를 파악해서 이동하고자하는 경로 계획(path planning)을 해야 하며 이러한 경로는 주행 시간, 소모되는 에너지, 안정성에 대한 고려가 되어야 하고 계산된 경로를 따라가기 위한 경로 추종(path tracking) 제어기가 있어야 한다. 그리고 경로 계획은 크게 두 부분으로 나뉘어지는데 먼저 오프라인(off-line)으로 이미 알려진 환경의 지도나 모델을 이용하는 광역 경로 계획(global path planning)과 실시간으로 바뀌어가는 환경에 적응하기 위해 온라인(on-line)으로 상황을 판단하는 국지적 경로 계획(local path planning)이 있다.즉 이동 로봇을 실용화하기 위해서는 로봇의 위치 추정 및 장애물 회피를 위한 경로 계획 그리고 센서를 이용한 제어 기술이 요구된다. 경로 계획은 장애물이 존재하는 작업 환경 내에서 로봇의 위치로부터 목표점까지 장애물을 피해 최적 경로로 이동하는 것을 목적으로 하는데, 이러한 목적을 이루기 위해서 이동 로봇은 외부에서 획득한 환경 정보

Restricted dynamic observer error linearizability

Following the general dynamic observer error linearization problem, state equivalence to a triangular nonlinear observer canonical form with index d and the restricted dynamic observer error linearization problem are defined. In this paper, the necessary and sufficient conditions for the above two problems are given. Since our proofs are constructive, a desired state transformation can also be found in the theorem.

Implementation of Intelligent and Human-Friendly Home Service Robot

Robot systems have applied to manufacturing or industrial field for reducing the need for human presence in dangerous and/or repetitive tasks. However, robot applications are transformed from industrial field to human life in recent tendency Nowadays, final goal of robot is to make a intelligent robot that can understand what human say and learn by itself and have internal emotion. For example Home service robots are able to provice functions such as security, housework, entertainment, education and secretary To provide various functions, home robots need to recognize human`s requirement and environment, and it is indispensable to use artificial intelligence technology for implementation of home robots. In this paper, implemented robot system takes data from several sensors and fuses the data to recognize environment information. Also, it can select a proper behavior for environment using soft computing method. Each behavior is composed with intuitive motion and sound in order to let human realize robot behavior well.

An Intelligent Auto Parking System for Vehicles

Autoparking assistant systems are a new and very promising area in automotive systems engineering. Since the traffic in modern cities becomes more intense, it is getting harder for a driver. Those systems are necessary for an inexperienced one to find a proper parking slot, or to park in a narrow parking slot without damaging his car or the vehicles around. The implementation of autoparking assistant systems may reduce drivers’ stress and make parking generally more comfortable. In addition, such system can be extremely useful for senior or disabled people or for drivers with reduced mobility. The implementation of autoparking assistant systems may increase the safety of the parking, and therefore the development of such systems is a highly-demanded task. We introduce an intelligent autoparking system that automatically generates trajectory for parking using a fuzzy logic. This paper consists of three parts. In first part we introduce trajectory generation method for parallel parking without collisions. Fuzzy-logic based trajectory generation algorithm is described in second part. Experimental results presented in the third part of the paper prove effectiveness of the proposed method.

Memory Management Model Using Combined ART and Fuzzy Logic

The human being receives a new information from outside and the information shows gradual oblivion with time. But the information remains in memory and isn`t forgotten for a long time if the information is read several times over. For example, we assume that we memorize a telephone number when we listen and never remind we may forget it soon, but we commit to memory long time by repeating. If the human being received new information with strong stimulus, it could remain in memory without recalling repeatedly. The moments of almost losing one`s life in an accident or getting a stroke of luck are rarely forgiven. The human being can keep memory for a long time in spite of the limit of memory for the mechanism mentioned above. In this paper, we propose a model to explain the mechanism mentioned above using a neural network and fuzzy.

Tracking Methods of User Position for Privacy Problems in Location Based Service

Development of new information and traffic technology causes fast-growing in the field of information-based system. At recent, development of LBS(Location Based Service) makes a remarkable growth of industry as GPS(Global Positioning System) becomes wide-spread and location information becomes more important. However, there is a problem like infringement of privacy when location information is used improperly［1］. In this paper, LBS platform is proposed in order to prevent infringement of privacy. To implement, we classify user path as pattern in a zone of user life. Thereupon, location information is provided according to user` specific situation.

Interval Type-2 Fuzzy Logic Control System of Flight Longitudinal Motion

The flight control of aircraft, which has nonlinear time-varying dynamic characteristics depending on the various and unexpected external conditions, can be performed on two motions: longitudinal motion and lateral motion. In the longitudinal motion control of aircraft, pitch and trust are major control parameters and roll and yaw are control ones in the lateral motion control. Until now, a number of efficient and reliable control schemes that can guarantee the stability and maneuverability of the aircraft have been developed. Recently, the intelligent flight control scheme, which differs from the conventional control strategy requiring the various and complicate procedures such as the wind tunnel and environmental experiments, has attracted attention. In this paper, an intelligent longitudinal control scheme has been proposed utilizing Interval Type-2 fuzzy logic which can be recognized as a representative intelligent control methodology. The results will be verified through computer simulation with a F-4 jet fighter.

The Implementation of the Intelligent Exoskeleton Robot Arm Using ElectroMiogram(EMG) vital Signal

The purpose of this study is to estimate a validity of control signal through a design of Exoskeleton Robot Arm`s capable of intelligent recognition as a human arm`s motion by using realtime processed data of generated EMG signals. By an intelligent algorithm, the EMG output value of human biceps and triceps muscles contraction can be recognized and used for the control over exoskeleton arm corresponding to human`s recognition and judgement. The EMG sensing data of muscles contraction and relaxation are used as the input signal from human`s body to operate the Exoskeleton Robot Arm thus copying human arm motion. An intelligent control of Exoskeleton Robot Arm is to design the analog control circuit which processes the input data, and then to manufacture an integrated control board. And then abstracted signal is passed by DSP signal processing, Fuzzy logic algorithm is designed for a accurate prediction of weight or load through the intelligent algorithm, and design an Exoskeleton Robot Arm to express a human`s intention.