• 한국자동차공학회논문집
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• 제5권2호
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• pp.13-22
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• 1997

Power flow characteristics of a hydro-mechanical transmission system(HMT) are investigated for tracked vehicle in steering. A HMT consisting of two hydrostatic pump motors(HST), several planetary gear trains and steer differential gear is considered. In order to obtain the direction and magnitude of the power flow of the HMT, network theory for the general power transmission is used. Network model for the HMT in steering is developed, which consists of shafts, nodes and transmission elements such as clutch, gear, etc. Power flow analysis procedure consists of two stages : (1) traction force analysis in steering, (2) power flow analysis in HMT. Torque and speed of every transmission element of the HMT is determined from the network analysis. Also, efficiency, mechanical and hydraulic power loss including HST, are obtained. In addition, the regenerative power flow resulting from steering can be studied in graphic display. The power flow analysis program(PCSTEER) developed in this work can be used as a useful design tool for the tracked vehicle with HMT.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.311-312
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• 2006

In this paper, steering systems for mobile robot with permanent magnet wheels are discussed. The mobile robot with permanent magnet wheels can have three different types of steering and driving configurations; two-wheels, three-wheels, four-wheels. By a Two-WD(Wheel Driving) system, driving and steering characteristics are controlled by ratio of each wheel speeds. Three-WD system is steered by a front wheel and driven by rear wheels. Four-WD system has better stability than two wheel system. Usually the permanent magnet wheel has nearly none slip. Thus turning radius of the mobile robot with three-WD and four-WD System will be increased and the steering and driving system will be complicated. To solve this problem, two magnet wheels with two dummy wheels are used in this study. fuming radius of the developed mobile robot is small and the structure of the robot is simple. It is possible to move forward, backward, to turn left and right, and to rotate freely with two-WD. This study proved that two-WD system is very suitable fur the mobile robot with permanent magnet wheels.

• 제어로봇시스템학회논문지
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• 제17권4호
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• pp.313-320
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• 2011

Multi-axle driving vehicles that are used in special environments require high driving performance, steering performance, and stability. Among these vehicles, 6WS/6WD vehicles with middle wheels have structural safety by distributing the load and reducing the pitch angle during rapid acceleration and braking. 6WS/6WD vehicles are favored for military use in off road operations because of their high maneuverability and mobility on extreme terrains and obstacles. 6WD vehicles that using in-wheel motor can generate the independent wheel torque without other mechanical parts. Conventional vehicles, however, cannot generate an opposite driving force at each side wheel. Using an independent steering and driving system, six-wheel vehicles can show better performance than conventional vehicles. Using of independent steering and driving system, the 6 wheel vehicle can improve a performance better than conventional vehicle. This vehicle enhances the maneuverability under low speed and the stability at high speed. This paper describes an independent 6WS/6WD vehicle, consists of three parts; Vehicle Model, Control Algorithm for 6WS/6WD and Simulation. First, vehicle model is application of TruckSim software for 6WS and 6WD. Second, control algorithm describes the optimum tire force distribution method in view of energy saving. Last is simulation and verification.

• 한국정밀공학회지
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• 제29권7호
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• pp.745-752
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• 2012

The pivot steering of an individual wheel motor drive vehicle is an effective steering maneuver in the narrow road, but it has become a matter of concern that the torque input of each wheel is very difficult to determine. In this study, the independent yaw moment control was proposed for the smooth pivot steering control of an in-wheel drive vehicle. For this control method, the vertical forces of tires were estimated from the trailing arm dynamic model, and the yaw moments of individual wheels were calculated from the vehicle dynamic model. Dynamic simulation results showed that the independent yaw moment control was much more effective on the minimization of the instabilities of pivot steering in comparison with the conventional direct yaw moment control with yaw rate feedback.

• 산업경영시스템학회지
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• 제29권4호
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• pp.1-7
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• 2006

This study determined the optimal positions of the movable steering wheel and pedal systems of industrial vehicle by various body dimensions. The position of objects and starting driving posture were measured by Martin-type anthropometer and goniometer. The X, Y and Z axis of movable steering wheel and pedal systems were measured horizon distance from right side to left side, horizon distance from front side to rear side and vertical distance from floor to ceiling. During the experiment in order to exclude learning effectiveness with forklift driving, 27 subjects who had male not experiences in driving a forklift used in the experiment. The relationship between the position of steering wheel and driver's posture with body dimensions was analyzed by using correlation relation and paired comparison t-test based on the measured data. The pedal location in X and Z axises was not related with various body dimensions. Also, the steering wheel was different among the angles of the right elbow and shoulder depending on the various body dimensions.

• 한국기계가공학회지
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• 제21권9호
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• pp.92-97
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• 2022

In this paper, as a research on autonomous steering for agriculture, a sensor module for furrow recognition was developed through a low-cost distance sensor combination. The developed sensor module was applied to the vehicle, and when driving in a furrow curve, the autonomous steering success rate was 100% at a curvature of 20 m or more, and 70% at a curvature of 15 m or less. The self-steering success rate according to the ground condition showed a 100% success rate regardless of soil, weeds, or mulching film.

• 한국철도학회논문집
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• 제10권6호
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• pp.709-716
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• 2007

철도차량의 주행안정성과 곡선추종성능을 동시에 획기적으로 개선하기 위한 능동조향대차의 가능성은 이론적으로는 계속적으로 검증되어 왔지만 능동제어를 위한 정보획득 문제, 부수적인 기계요소, 높은 에너지 소비, 고장에 대비한 안전기능 등과 같이 해결해야할 기술적 난제 때문에 많은 노력에도 불구하고 아직까지 상용화되지 못하고 있다. 이러한 문제점을 해결하고자, 본 논문에서는 보다 진보된 능동조향 메커니즘을 제안하고자 한다. 본 논문의 메커니즘을 이용하면 적은 제어력만 필요하기 때문에 기어와 같은 동력 전달장치가 필요 없고, 그 결과 추가되는 기계요소의 개수를 최소화 할 수 있으며 안전장치 또한 쉽게 구축이 가능하다. 본 논문에서는 제안된 능동조향대차의 개념에 관하여 소개하고 선형동적모델을 이용한 컴퓨터 모의실험을 통해 가능성을 검증하고자 한다.

• 대한전자공학회논문지SP
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• 제48권5호
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• pp.115-122
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• 2011

조향벡터(steering vector)에 에러가 있으면 적응 어레이(adaptive array)는 심한 성능저하를 겪게 된다. 이러한 에러로 인한 성능저하를 개선하기위해 DCRCB(doubly constrained robust Capon beamformer)에서는 벡터 norm 제한아래 구체 불확실 집합(spherical uncertainty set) 내의 벡터 중 출력전력을 최대로 하는 벡터를 조향벡터(steering vector)로 사용한다. 좋은 성능 개선을 위해서 불확실 집합의 반경, 즉 불확실 한계를 적절히 설정해야 하는 문제가 있다. 본 논문에서는 이를 해결하기 위해 반복탐색을 통해 조향벡터를 구하는 방식을 제안한다. 기존의 알려진 반복탐색 방식에서는 반복 종료를 위해 어떤 기준값을 결정해야 하는데, 이에 따른 어려움이 있다. 제안방식에서는 추정된 벡터와 신호부공간 거리가 더 이상 작아 지지 않으면 반복을 종료하며, 값 설정과 관련된 어떤 어려움도 없다. 시뮬레이션 결과에 따르면, 제안방식은 기존반복방식 그리고 최적의 불확실 한계로 설정된 표준 DCRCB 보다도 우수한 성능을 보여준다.

• 전자공학회논문지 IE
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• 제49권2호
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• pp.30-39
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• 2012

졸음운전은 사고발생 확률이 높고, 사고 발생 시 심각도가 높기 때문에 효율적인 졸음운전 판단 시스템이 필요하다. 그러나 생체 신호나 비전을 이용한 졸음운전 판단시스템은 비용 측면에서 활용되기가 어렵다. 이에 본 논문에서는 추가적인 비용 없이 대부분의 차량에 기본 장착되어 있는 조향각 센서(steering angle sensor)와 차량정보(brake switch, throttle position signal, vehicle speed)를 이용하여 졸음운전자의 조향패턴 중 하나인 저킹 판단을 이용한 졸음운전 판단 알고리즘을 제안한다. 본 연구에서는 각 변수의 임계값을 제시하고, HILS(Hardware in the Loop Simulation)에서 CAN을 통해 취득한 차량의 데이터와 Matlab 프로그램을 이용하여 알고리즘을 평가한다.

• 한국인터넷방송통신학회논문지
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• 제14권5호
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• pp.223-230
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• 2014

본 논문에서는 5.8GHz ISM 대역(5.725GHz~5.825GHz)의 저가 3차원 빔 조향을 위한 단일급전 마이크로스트립 기생 배열 안테나를 설계 및 제작하였다. 안테나는 단일 급전 능동소자와 가변 리액턴스 부하를 갖는 4개의 기생소자로 구성된다. 제작된 안테나의 빔 조향 범위는 가변 리액턴스 부하의 조절에 의해 방위각 ${\Phi}=0^{\circ}$, ${\Phi}=45^{\circ}$, ${\Phi}=90^{\circ}$, ${\Phi}=135^{\circ}$에서 ${\pm}28^{\circ}$의 3차원 빔 조향을 이룰 수 있었다. 빔 조향 범위 내에서 안테나의 최대이득은 7.23dBi~9.36dBi를 가지고, -10dB 이하 반사손실대역폭은 빔 조향각도에 상관없이 항상 5.8GHz ISM 대역을 포함하였다.